2021 |
Wang J, Zhang X, Li H, Wang C, Li H, Keller S, et al., 'pH-Dependent surface charge at the interfaces between aluminum gallium nitride (AlGaN) and aqueous solution revealed by surfactant adsorption', Journal of Colloid and Interface Science, 583 331-339 (2021)
© 2020 Hypothesis: The net surface charge of AlGaN/GaN structures, where AlGaN is in contact with the solution, is controlled by the pH-dependent protonation and deprotonation of ... [more]
© 2020 Hypothesis: The net surface charge of AlGaN/GaN structures, where AlGaN is in contact with the solution, is controlled by the pH-dependent protonation and deprotonation of the surface hydroxyl groups and possibly the electron-deficient surface electronic states. We hypothesize that atomic force microscopy (AFM) force measurements of ionic surfactant adsorption can reveal how the AlGaN surface properties vary with pH. Experiments: AFM force curves and images were used to probe the AlGaN/solution interface in water as a function of pH, and with added cationic surfactant cetyltrimethylammonium bromide (CTAB) or anionic surfactant sodium dodecylsulfate (SDS). Findings: The AlGaN/solution interface is negatively charged at pH 12, has an isoelectric point near pH 5.5, and is positively charged at pH values less than 5.5. Surfactant adsorption data suggests AlGaN surface is somewhat hydrophobic at acidic pH. Compared to gallium nitride (GaN), at pH 2, AlGaN has a lower charge density and hydrophobicity, but at other values of pH, the surface properties of AlGaN and GaN are similar.
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2020 |
Miao S, Wood J, Jiang HJ, Imberti S, Atkin R, Warr G, 'Unusual origin of choline phenylalaninate ionic liquid nanostructure', JOURNAL OF MOLECULAR LIQUIDS, 319 (2020)
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2020 |
Cook A, Jones TW, Wang JTW, Li H, Atkin R, Duffy NW, et al., 'Passivation by pyridine-induced PbI2 in methylammonium lead iodide perovskites', RSC Advances, 10 23829-23833 (2020) [C1]
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2020 |
Lopez R, Li H, Norret M, Iyer S, Biggs S, Atkin R, 'Robust Hydrophobic Coatings Using Polymer Blends for the Surface Protection of Marble', Colloids and Surfaces A: Physicochemical and Engineering Aspects, 599 (2020)
© 2020 Elsevier B.V. The use of marble in construction is limited by its susceptibility to water spill and weathering. Here, a series of poly (2,2,2-trifluoroethyl methacrylate) (... [more]
© 2020 Elsevier B.V. The use of marble in construction is limited by its susceptibility to water spill and weathering. Here, a series of poly (2,2,2-trifluoroethyl methacrylate) (PTFEMA) and poly (methacrylic acid) (PMAA) blend films have been coated on a marble surface to test their water spill and weathering protection capability. The morphologies of the coated polymer films on marble (i.e. surface defects and roughness) were investigated using atomic force microscopy (AFM). The hydrophobicity, adhesion strength and wear resistance of the coated films on marble were evaluated using water contact angle measurement, peel test and nanoindentation, respectively. An optimal combination of characteristics was seen when blending small amounts of PMAA (5% < x < 20 %) with PTFEMA. For these blends, the adhesion to marble and wear resistance of the coated films increased strongly over a pure PTFEMA coating, while maintaining a beneficial high water contact angle.
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2020 |
Warr GG, Atkin R, 'Solvophobicity and amphiphilic self-assembly in neoteric and nanostructured solvents', CURRENT OPINION IN COLLOID & INTERFACE SCIENCE, 45 83-96 (2020)
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2020 |
Pan H, Geysens P, Putzeys T, Gennaro A, Yi Y, Li H, et al., 'Physicochemical study of diethylmethylammonium methanesulfonate under anhydrous conditions', Journal of Chemical Physics, 152 (2020)
© 2020 Author(s). The protic ionic liquid diethylmethylammonium methanesulfonate ([DEMA][OMs]) was analyzed in depth by differential scanning calorimetry (DSC), nuclear magnetic r... [more]
© 2020 Author(s). The protic ionic liquid diethylmethylammonium methanesulfonate ([DEMA][OMs]) was analyzed in depth by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, and broadband dielectric spectroscopy (BDS) under anhydrous conditions. Karl Fischer titration, NMR, and FT-IR spectra confirmed the high purity of [DEMA][OMs]. The melting point (37.7 °C) and the freezing point (14.0 °C) obtained by DSC agree well with the values determined by BDS (40.0 °C and 14.0 °C). The dc conductivity (sdc) above the melting/freezing point obeys the Vogel-Fulcher-Tammann (VFT) equation well, and thus, the proton conduction in [DEMA][OMs] is assumed to be dominated by the vehicle mechanism. In contrast, the sdc below the melting/freezing point can be fitted by the Arrhenius equation separately, and therefore, the proton conduction is most likely governed by the proton hopping mechanism. The non-negligible influence of previously reported low water content on the physicochemical properties of [DEMA][OMs] is found, indicating the importance of reducing water content as much as possible for the study of "intrinsic"properties of protic ionic liquids.
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2020 |
Rakov DA, Chen F, Ferdousi SA, Li H, Pathirana T, Simonov AN, et al., 'Engineering high-energy-density sodium battery anodes for improved cycling with superconcentrated ionic-liquid electrolytes', Nature Materials, 19 1096-1101 (2020)
© 2020, The Author(s), under exclusive licence to Springer Nature Limited. Non-uniform metal deposition and dendrite formation in high-density energy storage devices reduces the e... [more]
© 2020, The Author(s), under exclusive licence to Springer Nature Limited. Non-uniform metal deposition and dendrite formation in high-density energy storage devices reduces the efficiency, safety and life of batteries with metal anodes. Superconcentrated ionic-liquid electrolytes (for example 1:1 ionic liquid:alkali ion) coupled with anode preconditioning at more negative potentials can completely mitigate these issues, and therefore revolutionize high-density energy storage devices. However, the mechanisms by which very high salt concentration and preconditioning potential enable uniform metal deposition and prevent dendrite formation at the metal anode during cycling are poorly understood, and therefore not optimized. Here, we use atomic force microscopy and molecular dynamics simulations to unravel the influence of these factors on the interface chemistry in a sodium electrolyte, demonstrating how a molten-salt-like structure at the electrode surface results in dendrite-free metal cycling at higher rates. Such a structure will support the formation of a more favourable solid electrolyte interphase, accepted as being a critical factor in stable battery cycling. This new understanding will enable engineering of efficient anode electrodes by tuning the interfacial nanostructure via salt concentration and high-voltage preconditioning.
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2020 |
Bryant SJ, Atkin R, Gradzielski M, Warr GG, 'Catanionic Surfactant Self-Assembly in Protic Ionic Liquids', JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 11 5926-5931 (2020)
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2020 |
Li H, Niemann T, Ludwig R, Atkin R, 'Effect of Hydrogen Bonding between Ions of Like Charge on the Boundary Layer Friction of Hydroxy-Functionalized Ionic Liquids', JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 11 3905-3910 (2020)
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2020 |
Evans CW, Ho D, Lee PKH, Martin AD, Chin IL, Wei Z, et al., 'A dendronised polymer architecture breaks the conventional inverse relationship between porosity and mechanical properties of hydrogels.', Chem Commun (Camb), (2020)
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2020 |
Karton A, Brunner M, Howard MJ, Warr GG, Atkin R, 'Erratum: The High Performance of Choline Arginate for Biomass Pretreatment Is Due to Remarkably Strong Hydrogen Bonding by the Anion (Journal of Chemical Theory and Computation (2018) 6:3 (4115-4121) DOI: 10.1021/acssuschemeng.7b04489)', ACS Sustainable Chemistry and Engineering, (2020)
© 2020 American Chemical Society. All rights reserved. In our original article,1 we have incorrectly modeled the cholinium cation in [Arg][Ch] and [Gly][Ch] ILs as a 3- trimethyla... [more]
© 2020 American Chemical Society. All rights reserved. In our original article,1 we have incorrectly modeled the cholinium cation in [Arg][Ch] and [Gly][Ch] ILs as a 3- trimethylaminopropan-1-ol cation. This error affects the Hbonds for the [Arg][Ch] E E EX and [Gly][Ch] E E EX systems (X = HOH, HOMe, HOPh, H2NMe, and H2C LNH) reported in Table 2 of the original article (page 4118). The H-bonds reported in this table are consistent with the experiment in that they demonstrate that for any given H-bond donor (X) the Hbond in [Arg][Ch] E E EX is significantly stronger than that in [Gly][Ch. E.
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2020 |
Brunner M, Imberti S, Warr GG, Atkin R, 'Liquid Structure of Single and Mixed Cation Alkylammonium Bromide Urea Deep Eutectic Solvents', JOURNAL OF PHYSICAL CHEMISTRY B, 124 8651-8664 (2020)
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2020 |
Miao S, Atkin R, Warr GG, 'Amphiphilic nanostructure in choline carboxylate and amino acid ionic liquids and solutions', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 22 3490-3498 (2020)
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2020 |
Li H, Choi YS, Rutland MW, Atkin R, 'Nanotribology of hydrogels with similar stiffness but different polymer and crosslinker concentrations', Journal of Colloid and Interface Science, 563 347-353 (2020)
© 2019 Elsevier Inc. Hypothesis: The stiffness has been found to regulate hydrogel performances and applications. However, the key interfacial properties of hydrogels, like fricti... [more]
© 2019 Elsevier Inc. Hypothesis: The stiffness has been found to regulate hydrogel performances and applications. However, the key interfacial properties of hydrogels, like friction and adhesion are not controlled by the stiffness, but are altered by the structure and composition of hydrogels, like polymer volume fraction and crosslinking degree. Experiments: Colloidal probe atomic force microscopy has been use to investigate the relationship between tribological properties (friction and adhesion) and composition of hydrogels with similar stiffness, but different polymer volume fractions and crosslinking degrees. Findings: The interfacial normal and lateral (friction) forces of hydrogels are not directly correlated to the stiffness, but altered by the hydrogel structure and composition. For normal force measurements, the adhesion increases with polymer volume fraction but decreases with crosslinking degree. For lateral force measurements, friction increases with polymer volume fraction, but decreases with crosslinking degree. In the low normal force regime, friction is mainly adhesion-controlled and increases significantly with the adhesion and polymer volume fraction. In the high normal force regime, friction is predominantly load-controlled and shows slow increase with normal force.
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2019 |
Cooper PK, Staddon J, Zhang S, Aman ZM, Atkin R, Li H, 'Nano- and macroscale study of the lubrication of titania using pure and diluted ionic liquids', Frontiers in Chemistry, 7 (2019)
© 2019 Cooper, Staddon, Zhang, Aman, Atkin and Li. Titanium is a strong, corrosion-resistant light - weight metal which is poised to replace steel in automobiles, aircraft, and wa... [more]
© 2019 Cooper, Staddon, Zhang, Aman, Atkin and Li. Titanium is a strong, corrosion-resistant light - weight metal which is poised to replace steel in automobiles, aircraft, and watercraft. However, the titanium oxide (titania) layer that forms on the surface of titanium in air is notoriously difficult to lubricate with conventional lubricants, which restricts its use in moving parts such as bearings. Ionic liquids (ILs) are potentially excellent lubricants for titania but the relationship between IL molecular structure and lubricity for titania remains poorly understood. Here, three-ball-on-disk macrotribology and atomic force microscopy (AFM) nanotribology measurements reveal the lubricity of four IL lubricants: trioctyl(2-ethylhexyl)phosphonium bis(2 ethylhexyl)phosphate (P8,8,8,6(2) BEHP), trihexyl(tetradecyl)phosphonium bis(2 ethylhexyl)phosphate (P6,6,6,14 BEHP), trihexyl(tetradecyl)phosphonium bis(2,4,4 trimethylpentyl)phosphinate (P6,6,6,14 (iC8)2PO2), and trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide (P6,6,6,14 TFSI). The macrotribology measurements demonstrated that friction decreased in P6,6,6,14 TFSI by four times (µ = 0.13) compared to in hexadecane, even at 60 °C and loads up to 10 N. On the other hand, P8,8,8,6(2) BEHP reduced friction most effectively in the AFM nanotribology measurements. The results were interpreted in terms of the lubrication regime. The lower viscosity of P6,6,6,14 TFSI coupled with its good boundary lubrication made it the most effective IL for the macrotribology measurements, which were in the mixed lubrication regime. Conversely, the cation structure the P8,8,8,6(2) BEHP allowed it to adsorb strongly to the surface and minimized energy dissipation in the nanotribology measurements, although its high bulk viscosity inhibited its performance in the mixed regime. These results reinforce the importance of carefully selecting IL lubricants based on the lubrication regime of the sliding surfaces.
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2019 |
Hammond OS, Li H, Westermann C, Al-Murshedi AYM, Endres F, Abbott AP, et al., 'Nanostructure of the deep eutectic solvent/platinum electrode interface as a function of potential and water content', NANOSCALE HORIZONS, 4 158-168 (2019)
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2019 |
Stefanovic R, Chen Z, FitzGerald PA, Warr GG, Atkin R, Page AJ, Webber GB, 'Effect of halides on the solvation of poly(ethylene oxide) in the ionic liquid propylammonium nitrate.', Journal of Colloid and Interface Science, 534 649-654 (2019) [C1]
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2019 |
Bryant SJ, Jafta CJ, Atkin R, Gradzielski M, Warr GG, 'Catanionic and chain-packing effects on surfactant self-assembly in the ionic liquid ethylammonium nitrate', JOURNAL OF COLLOID AND INTERFACE SCIENCE, 540 515-523 (2019)
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2019 |
Haeckl K, Li H, Aldous IM, Tsui T, Kunz W, Abbott AP, et al., 'Potential Dependence of Surfactant Adsorption at the Graphite Electrode/Deep Eutectic Solvent Interface', JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 10 5331-5337 (2019)
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2019 |
Niemann T, Li H, Warr GG, Ludwig R, Atkin R, 'Influence of Hydrogen Bonding between Ions of Like Charge on the Ionic Liquid Interfacial Structure at a Mica Surface', JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 10 7368-7373 (2019)
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2019 |
Lam MT, Adamson WD, Miao S, Atkin R, Warr GG, 'DTAB micelle formation in ionic liquid/water mixtures is determined by ionic liquid cation structure', JOURNAL OF COLLOID AND INTERFACE SCIENCE, 552 597-603 (2019)
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2019 |
Mao X, Brown P, Cervinka C, Hazell G, Li H, Ren Y, et al., 'Self-assembled nanostructures in ionic liquids facilitate charge storage at electrified interfaces', NATURE MATERIALS, 18 1350-+ (2019)
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2019 |
Zheng C, Brunner M, Li H, Zhang D, Atkin R, 'Dissolution and suspension of asphaltenes with ionic liquids', Fuel, 238 129-138 (2019)
© 2018 Asphaltenes, which comprise polycyclic aromatic hydrocarbon cores with attached short aliphatic side chains, are the most polar fraction of crude oils. Asphaltenes are pron... [more]
© 2018 Asphaltenes, which comprise polycyclic aromatic hydrocarbon cores with attached short aliphatic side chains, are the most polar fraction of crude oils. Asphaltenes are prone to precipitation, which requires expensive cleaning procedures using solvents like toluene or xylene. The toxicity and high vapour pressures of toluene and xylene means there is an urgent need for new liquids that are able to dissolve or suspend asphaltenes but are less environmentally problematic. This study reports treatment results of asphaltenes with 16 different ionic liquids covering three different types of cation charge groups, namely, cholinium, imidazolium and phosphonium with a wide variety of anions. The two oil-miscible ionic liquids, trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylphentyl)phosphinate and trihexyl(tetradecyl)phosphonium bis(2-ethylhexyl)phosphate, solubilised or suspended a significant fraction of raw asphaltenes. Elemental analysis, TGA and FTIR revealed that asphaltenes recovered from these ionic liquids had increased aliphatic and oxygen content compared to the raw material, and decomposed at lower temperatures during TGA test. The relative hydrophobicity of the ionic liquid is the major factor controlling the asphaltene mass in the ionic liquid, followed by the strength of interactions between ionic liquid and asphaltene alkyl groups. These findings provide a platform for the development of new ionic liquid based cleaners for asphaltene deposits.
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2019 |
Halder P, Kundu S, Patel S, Setiawan A, Atkin R, Parthasarthy R, et al., 'Progress on the pre-treatment of lignocellulosic biomass employing ionic liquids', Renewable and Sustainable Energy Reviews, 105 268-292 (2019)
© 2019 Elsevier Ltd The effective pre-treatment methods are required for the destruction of the complex biomass structure to economically produce high grade fuels and valuable pla... [more]
© 2019 Elsevier Ltd The effective pre-treatment methods are required for the destruction of the complex biomass structure to economically produce high grade fuels and valuable platform chemicals. Ionic liquids have high potential for energy efficient biomass pre-treatment due to their low vapour pressure, emission profile, recyclability and tuneable properties; some ionic liquids can even be prepared from renewable biomass feedstocks. However, a number of issues currently impede the large scale uptake of ionic liquids including their cost of production, detailed understanding the macro, micro and molecular level deconstruction mechanisms which inhibits process optimisation and modelling, and the need for techno-economic astable sessment on large scale trials. So far, laboratory to bench scale IL pre-treatments of various lignocellulosic biomasses were studied by changing various process parameters where the aims were to investigate the biomass dissolution mechanism and understand the pre-treatment performance of ILs. This review outlines current research gaps and potential applications for ionic liquids in the destruction of biomass into its components followed by separation of lignin, hemicellulose and cellulose rich fractions.
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2019 |
Jiang HJ, Imberti S, Simmons BA, Atkin R, Warr GG, 'Structural Design of Ionic Liquids for Optimizing Aromatic Dissolution', CHEMSUSCHEM, 12 270-274 (2019)
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2019 |
Chua ET, Brunner M, Atkin R, Eltanahy E, Thomas-Hall SR, Schenk PM, 'The Ionic Liquid Cholinium Arginate Is an Efficient Solvent for Extracting High-Value Nannochloropsis sp. Lipids', ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 7 2538-2544 (2019)
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2019 |
Hjalmarsson N, Bergendal E, Wang Y-L, Munavirov B, Wallinder D, Glavatskih S, et al., 'Electro-Responsive Surface Composition and Kinetics of an Ionic Liquid in a Polar Oil', LANGMUIR, 35 15692-15700 (2019)
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2019 |
Brunner M, Li H, Zhang Z, Zhang D, Atkin R, 'Pinewood pyrolysis occurs at lower temperatures following treatment with choline-amino acid ionic liquids', Fuel, 236 306-312 (2019)
© 2018 Elsevier Ltd Pinewoods are the dominant species in Australian softwood plantations and an important source of renewable lignocellulosic biomass. This work examines interact... [more]
© 2018 Elsevier Ltd Pinewoods are the dominant species in Australian softwood plantations and an important source of renewable lignocellulosic biomass. This work examines interactions between cholinium amino acid (Ch[AA]) ionic liquid (IL) ¿ Water mixtures and pinewood. The Ch[AA] ILs employed were cholinium arginate (Ch[Arg]), cholinium glycinate (Ch[Gly]), and cholinium aspartate (Ch[Asp]), with water contents between 32 and 42 wt%. Pinewood and Ch[AA] ILs were mixed at 90 °C for all samples, and also 120 °C for Ch[Arg], as it dissolved the most biomass at 90 °C. Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), x-ray diffraction (XRD), and compositional (CHNS) analysis were performed on the raw and treated biomass samples to reveal the changes in physical and chemical properties. While Ch[Arg] solubilised the greatest mass of biomass during treatment, the most pronounced changes in decomposition properties was obtained using Ch[Gly]. The TGA analysis revealed the maximum in the derivative weight loss data shifted to lower temperatures by 29 °C.
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2019 |
Wang J, Zhang X, Wang C, Li H, Li H, Keller S, et al., 'pH-dependent surface properties of the gallium nitride Solution interface mapped by surfactant adsorption', Journal of Colloid and Interface Science, 556 680-688 (2019)
© 2019 Hypothesis: The surface charge of gallium nitride (GaN) in contact with solution is controlled by pH via surface protonation and deprotonation, similar to silica. Ionic sur... [more]
© 2019 Hypothesis: The surface charge of gallium nitride (GaN) in contact with solution is controlled by pH via surface protonation and deprotonation, similar to silica. Ionic surfactants adsorb on surfaces via electrostatic and hydrophobic interactions and can be utilized to reflect the surface charge of GaN. Experiments: The surface charge properties of Ga-polar GaN in solution were probed as a function of pH using atomic force microscopy (AFM). AFM soft-contact images and force curves were used to study the pH-dependent adsorption of the cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecylsulfate (SDS) on GaN surfaces. To further confirm the AFM results, GaN/AlGaN/GaN heterostructure-based ion sensing devices were used to measure the surfactant adsorption over the same pH range. Findings: SDS aggregates adsorb on GaN below pH 2.75 while CTAB aggregates adsorb above pH 10. This shows that the GaN surface carries substantial net positive charge at low pH, and negative charge at high pH. There is no clear SDS or CTAB adsorption on the GaN surface between pH 3 and 9.75, which indicates the surface is weakly charged. GaN/AlGaN/GaN heterostructure-based devices confirm these results, and demonstrate the utility of these devices for measuring surfactant adsorption.
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2019 |
Niemann T, Neumann J, Stange P, Gartner S, Young TGA, Paschek D, et al., 'The Double-Faced Nature of Hydrogen Bonding in Hydroxy-Functionalized Ionic Liquids Shown by Neutron Diffraction and Molecular Dynamics Simulations', ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 58 12887-12892 (2019)
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2018 |
To TQ, Procter K, Simmons BA, Subashchandrabose S, Atkin R, 'Low cost ionic liquid-water mixtures for effective extraction of carbohydrate and lipid from algae', FARADAY DISCUSSIONS, 206 93-112 (2018) [C1]
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2018 |
Addicoat M, Atkin R, Canongia Lopes JN, Costa Gomes M, Firestone M, Gardas R, et al., 'Structure and dynamics of ionic liquids: General discussion', Faraday Discussions, 206 291-337 (2018)
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2018 |
Abbott A, Abe H, Aldous L, Atkin R, Bendová M, Busato M, et al., 'Phase behaviour and thermodynamics: General discussion', Faraday Discussions, 206 113-139 (2018)
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2018 |
Jiang HJ, Atkin R, Warr GG, 'Nanostructured ionic liquids and their solutions: Recent advances and emerging challenges', CURRENT OPINION IN GREEN AND SUSTAINABLE CHEMISTRY, 12 27-32 (2018)
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2018 |
Chen Z, Tonouchi Y, Matsumoto K, Saimura M, Atkin R, Nagata T, et al., 'Partially Naked Fluoride in Solvate Ionic Liquids', JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 9 6662-6667 (2018)
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2018 |
Cooper PK, Li H, Yepuri NR, Nelson A, Webber GB, Le Brun AP, et al., 'Ionic Liquid Adsorption at the Silica-Oil Interface Revealed by Neutron Reflectometry', Journal of Physical Chemistry C, 122 24077-24084 (2018) [C1]
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2018 |
Karton A, Brunner M, Howard MJ, Warr GG, Atkin R, 'The High Performance of Choline Arginate for Biomass Pretreatment Is Due to Remarkably Strong Hydrogen Bonding by the Anion', ACS Sustainable Chemistry and Engineering, 6 4115-4121 (2018) [C1]
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2018 |
McDonald S, Murphy T, Imberti S, Warr GG, Atkin R, 'Amphiphilically Nanostructured Deep Eutectic Solvents', Journal of Physical Chemistry Letters, 9 3922-3927 (2018) [C1]
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2018 |
Borisenko N, Lahiri A, Pulletikurthi G, Cui T, Carstens T, Zahlbach J, et al., 'The Au(111)/IL interfacial nanostructure in the presence of precursors and its influence on the electrodeposition process', FARADAY DISCUSSIONS, 206 459-473 (2018)
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2017 |
Bryant SJ, Atkin R, Warr GG, 'Effect of Deep Eutectic Solvent Nanostructure on Phospholipid Bilayer Phases', LANGMUIR, 33 6878-6884 (2017)
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2017 |
Stefanovic R, Ludwig M, Webber GB, Atkin R, Page AJ, 'Nanostructure, hydrogen bonding and rheology in choline chloride deep eutectic solvents as a function of the hydrogen bond donor', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19 3297-3306 (2017) [C1]
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2017 |
Hoffmann V, Lahiri A, Borisenko N, Carstens T, Pulletikurthi G, Borodin A, et al., 'Nanostructure of the H-terminated p-Si(111)/ionic liquid interface and the effect of added lithium salt', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19 54-58 (2017) [C1]
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2017 |
To TQ, Shah K, Tremain P, Simmons BA, Moghtaderi B, Atkin R, 'Treatment of lignite and thermal coal with low cost amino acid based ionic liquid-water mixtures', FUEL, 202 296-306 (2017) [C1]
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2017 |
Chen Z, Greaves TL, Warr GG, Atkin R, 'Mixing cations with different alkyl chain lengths markedly depresses the melting point in deep eutectic solvents formed from alkylammonium bromide salts and urea', CHEMICAL COMMUNICATIONS, 53 2375-2377 (2017) [C1]
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2017 |
Mozes R, Cooper PK, Atkin R, Li H, 'Ionic Liquids as Grease Base Liquids', LUBRICANTS, 5 (2017) [C1]
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2017 |
Li H, Rutland MW, Watanabe M, Atkin R, 'Boundary layer friction of solvate ionic liquids as a function of potential', FARADAY DISCUSSIONS, 199 311-322 (2017) [C1]
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2017 |
Jiang HJ, Imberti S, Atkin R, Warr GG, 'Dichotomous Well-defined Nanostructure with Weakly Arranged Ion Packing Explains the Solvency of Pyrrolidinium Acetate', JOURNAL OF PHYSICAL CHEMISTRY B, 121 6610-6617 (2017)
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2017 |
Cooper PK, Wear CJ, Li H, Atkin R, 'Ionic Liquid Lubrication of Stainless Steel: Friction is Inversely Correlated with Interfacial Liquid Nanostructure', ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 5 11737-11743 (2017)
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2017 |
Chen Z, Ludwig M, Warr GG, Atkin R, 'Effect of cation alkyl chain length on surface forces and physical properties in deep eutectic solvents', JOURNAL OF COLLOID AND INTERFACE SCIENCE, 494 373-379 (2017) [C1]
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2017 |
Hjalmarsson N, Atkin R, Rutland MW, 'Switchable long-range double layer force observed in a protic ionic liquid', CHEMICAL COMMUNICATIONS, 53 647-650 (2017) [C1]
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2017 |
Cook A, Ueno K, Watanabe M, Atkin R, Li H, 'Effect of Variation in Anion Type and Glyme Length on the Nanostructure of the Solvate Ionic Liquid/Graphite Interface as a Function of Potential', JOURNAL OF PHYSICAL CHEMISTRY C, 121 15728-15734 (2017) [C1]
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2017 |
Chen Z, McDonald S, FitzGerald P, Warr GG, Atkin R, 'Small angle neutron scattering study of the conformation of poly (ethylene oxide) dissolved in deep eutectic solvents', JOURNAL OF COLLOID AND INTERFACE SCIENCE, 506 486-492 (2017) [C1]
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2017 |
Cummings J, Tremain P, Shah K, Heldt E, Moghtaderi B, Atkin R, et al., 'Modification of lignites via low temperature ionic liquid treatment', FUEL PROCESSING TECHNOLOGY, 155 51-58 (2017) [C1]
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2017 |
Gebbie MA, Smith AM, Dobbs HA, Lee AA, Warr GG, Banquy X, et al., 'Long range electrostatic forces in ionic liquids', CHEMICAL COMMUNICATIONS, 53 1214-1224 (2017) [C1]
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2017 |
Cowie S, Cooper PK, Atkin R, Li H, 'Nanotribology of Ionic Liquids as Lubricant Additives for Alumina Surfaces', JOURNAL OF PHYSICAL CHEMISTRY C, 121 28348-28353 (2017) [C1]
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2017 |
Bryant SJ, Wood K, Atkin R, Warr GG, 'Effect of protic ionic liquid nanostructure on phospholipid vesicle formation', SOFT MATTER, 13 1364-1370 (2017) [C1]
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2016 |
Li H, Somers AE, Howlett PC, Rutland MW, Forsyth M, Atkin R, 'Addition of low concentrations of an ionic liquid to a base oil reduces friction over multiple length scales: A combined nano- and macrotribology investigation', Physical Chemistry Chemical Physics, 18 6541-6547 (2016) [C1]
© the Owner Societies 2016. The efficacy of ionic liquids (ILs) as lubricant additives to a model base oil has been probed at the nanoscale and macroscale as a function of IL conc... [more]
© the Owner Societies 2016. The efficacy of ionic liquids (ILs) as lubricant additives to a model base oil has been probed at the nanoscale and macroscale as a function of IL concentration using the same materials. Silica surfaces lubricated with mixtures of the IL trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate and hexadecane are probed using atomic force microscopy (AFM) (nanoscale) and ball-on-disc tribometer (macroscale). At both length scales the pure IL is a much more effective lubricant than hexadecane. At the nanoscale, 2.0 mol% IL (and above) in hexadecane lubricates the silica as well as the pure IL due to the formation of a robust IL boundary layer that separates the sliding surfaces. At the macroscale the lubrication is highly load dependent; at low loads all the mixtures lubricate as effectively as the pure IL, whereas at higher loads rather high concentrations are required to provide IL like lubrication. Wear is also pronounced at high loads, for all cases except the pure IL, and a tribofilm is formed. Together, the nano- and macroscales results reveal that the IL is an effective lubricant additive - it reduces friction - in both the boundary regime at the nanoscale and mixed regime at the macroscale.
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2016 |
Riazi H, Murphy T, Webber GB, Atkin R, Tehrani SSM, Taylor RA, 'Specific heat control of nanofluids: A critical review', International Journal of Thermal Sciences, 107 25-38 (2016) [C1]
© 2016 Elsevier Masson SAS. All rights reserved. Specific heat is a key thermal property in energy systems and is directly linked with heat storage and transfer. Concentrated sola... [more]
© 2016 Elsevier Masson SAS. All rights reserved. Specific heat is a key thermal property in energy systems and is directly linked with heat storage and transfer. Concentrated solar thermal (CST) power plants which incorporate thermal storage show promise to deliver affordable, renewable and reliable electricity without harmful emissions. As compared to wind and photovoltaic installations, which are intermittent, CST systems (with thermal storage) represent a technology which can be dispatched to provide a good match with energy demand - or at least to maximize revenue. At present, molten salts represent the dominant thermal storage medium. However, the low specific heat value of molten salts severely limits their applicability. Increasing the specific heat of molten salts could allow for a sizable reduction in storage volume, or for more energy to be stored in the same volume. Recently, researchers have shown that the specific heat of fluids can be altered through the addition of nanoparticles, although the fundamental governing mechanisms for the observed changes in this property have not yet been agreed upon. This paper provides a comprehensive review of recent, albeit sometimes contrary, nanofluid specific heat studies. Since a critical review of the ongoing work in this field has not yet been compiled, this paper provides insights into the range and magnitude of specific heat changes. This review also discusses possible underlying enhancement mechanisms, the impacts of colloidal stability, and uses these to rationalize the diverse range of results seen in the literature. Through reviewing the salient literature, it is hoped that this paper will help to guide future efforts in controlling the specific heat of nanosalts.
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2016 |
Cooper PK, Li H, Rutland MW, Webber GB, Atkin R, 'Tribotronic control of friction in oil-based lubricants with ionic liquid additives.', Phys Chem Chem Phys, 18 23657-23662 (2016) [C1]
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2016 |
Saito S, Watanabe H, Hayashi Y, Matsugami M, Tsuzuki S, Seki S, et al., 'Li(+) Local Structure in Li-Tetraglyme Solvate Ionic Liquid Revealed by Neutron Total Scattering Experiments with the (6/7)Li Isotopic Substitution Technique.', The journal of physical chemistry letters, 7 2832-2837 (2016) [C1]
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2016 |
Hjalmarsson N, Atkin R, Rutland MW, 'Effect of Lithium Ions on Rheology and Interfacial Forces in Ethylammonium Nitrate and Ethanolammonium Nitrate', Journal of Physical Chemistry C, 120 26960-26967 (2016) [C1]
© 2016 American Chemical Society. The effect of added Li+ to two ionic liquids (ILs), ethylammonium nitrate (EAN) and ethanolammonium nitrate (EtAN), has been investigated using r... [more]
© 2016 American Chemical Society. The effect of added Li+ to two ionic liquids (ILs), ethylammonium nitrate (EAN) and ethanolammonium nitrate (EtAN), has been investigated using rheology and colloidal probe atomic force microscopy (AFM). Rheology data revealed a complex viscosity dependence that can be ascribed to the different bulk nanostructures. AFM force curves revealed steps for the neat ILs, analogous to those in previous studies. The addition of Li+ broadened the steps, which is likely an effect of ion clusters formed. Friction measurements corroborate this data and also showed that the structure of EtAN is much more prone to change as Li+ is added. These results demonstrate the complex behavior of ILs on interfaces and the effect of perturbing such interactions. (Graph Presented).
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2016 |
Dolan A, Sherman DA, Atkin R, Warr GG, 'Kamlet-Taft Solvation Parameters of Solvate Ionic Liquids', CHEMPHYSCHEM, 17 3096-3101 (2016) [C1]
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2016 |
McDonald S, Elbourne A, Warr GG, Atkin R, 'Metal ion adsorption at the ionic liquid-mica interface', Nanoscale, 8 906-914 (2016) [C1]
© 2016 The Royal Society of Chemistry. Mica has been employed in many studies of ionic liquid (IL) interfaces on account of its atomic smoothness and well defined surface properti... [more]
© 2016 The Royal Society of Chemistry. Mica has been employed in many studies of ionic liquid (IL) interfaces on account of its atomic smoothness and well defined surface properties. However, until now it has been unclear whether ions dissolved in ILs can compete with the IL cation and adsorb to mica charge sites. In this work amplitude modulated atomic force microscopy (AM-AFM) has been used to probe metal ion adsorption at the interface of mica with propylammonium nitrate (PAN), a room temperature IL. Lithium, sodium, potassium, magnesium and calcium nitrate salts were added to PAN at a concentration of ~60 mM. Aluminum nitrate was also investigated, but only at 5 mM because its solubility in PAN is much lower. The AM-AFM images obtained when the metal ions were present are strikingly different to that of pure PAN, indicating that the ions compete effectively with the propylammonium cation and adsorb to negatively charged sites on the mica surface despite their much lower concentration. This is a consequence of electrostatic attractions between the mica charge sites and the metal ions being significantly stronger than for the propylammonium cation; compared to the metal ions the propylammonium charged group is relatively constrained sterically. A distinct honeycomb pattern is noted for the PAN + Al3+ system, less obviously for the divalent ions and not at all for monovalent ions. This difference is attributed to the strength of electrostatic interactions between metal ions and mica charge sites increasing with the ion charge, which means that divalent and (particularly) trivalent ions are located more precisely above the charged sites of the mica lattice. The images obtained allow important distinctions between metal ion adsorption at mica-water and mica-PAN interfaces to be made.
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2016 |
Hjalmarsson N, Atkin R, Rutland MW, 'Is the boundary layer of an ionic liquid equally lubricating at higher temperature?', Physical Chemistry Chemical Physics, 18 9232-9239 (2016) [C1]
© the Owner Societies 2016. Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethyl... [more]
© the Owner Societies 2016. Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C. Force curves revealed a strong fluid dynamic influence at room temperature, which was greatly reduced at elevated temperatures due to the reduced liquid viscosity. A fluid dynamic analysis reveals that bulk viscosity is manifested at large separation but that EAN displays a nonzero slip, indicating a region of different viscosity near the surface. At high temperatures, the reduction in fluid dynamic force reveals step-like force curves, similar to those found at room temperature using much lower scan rates. The ionic liquid boundary layer remains adsorbed to the solid surface even at high temperature, which provides a mechanism for lubrication when fluid dynamic lubrication is strongly reduced. The friction data reveals a decrease in absolute friction force with increasing temperature, which is associated with increased thermal motion and reduced viscosity of the near surface layers but, consistent with the normal force data, boundary layer lubrication was unaffected. The implications for ILs as lubricants are discussed in terms of the behaviour of this well characterised system.
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2016 |
Sweeney J, Webber GB, Atkin R, 'Poly(ethylene oxide) Mushrooms Adsorbed at Silica-Ionic Liquid Interfaces Reduce Friction', LANGMUIR, 32 1947-1954 (2016) [C1]
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2016 |
Murphy T, Hayes R, Imberti S, Warr GG, Atkin R, 'Ionic liquid nanostructure enables alcohol self assembly', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 18 12797-12809 (2016) [C1]
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2016 |
Murphy T, Callear SK, Warr GG, Atkin R, 'Dissolved chloride markedly changes the nanostructure of the protic ionic liquids propylammonium and ethanolammonium nitrate', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 18 17169-17182 (2016) [C1]
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2016 |
Murphy T, Callear SK, Yepuri N, Shimizu K, Watanabe M, Lopes JNC, et al., 'Bulk nanostructure of the prototypical 'good' and 'poor' solvate ionic liquids [Li(G4)][TFSI] and [Li(G4)][NO3]', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 18 17224-17236 (2016) [C1]
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2016 |
Black JJ, Murphy T, Atkin R, Dolana A, Aldous L, 'The thermoelectrochemistry of lithium-glyme solvate ionic liquids: towards waste heat harvesting', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 18 20768-20777 (2016) [C1]
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2016 |
Begic S, Li H, Atkin R, Hollenkamp AF, Howlett PC, 'A comparative AFM study of the interfacial nanostructure in imidazolium or pyrrolidinium ionic liquid electrolytes for zinc electrochemical systems', Physical Chemistry Chemical Physics, 18 29337-29347 (2016) [C1]
© the Owner Societies 2016. The electrochemical systems containing zinc dicyanamide salt (Zn(dca)2) in both 1-ethyl-3-methylimidazolium dicyanamide ([C2mim][dca]) and N-butyl-N-me... [more]
© the Owner Societies 2016. The electrochemical systems containing zinc dicyanamide salt (Zn(dca)2) in both 1-ethyl-3-methylimidazolium dicyanamide ([C2mim][dca]) and N-butyl-N-methylpyrrolidinium dicyanamide ([C4mpyr][dca]) ionic liquids (ILs) have been studied by atomic force microscopy (AFM) on a highly oriented pyrolytic graphite (HOPG) surface under different conditions and applied potentials. The results reveal the following: (1) interfacial layers exist in both ILs, even after the addition of 3 wt% water and 9 mol% Zn(dca)2 salt. (2) The number of layers is different for the different ILs, with the [C2mim][dca]-based samples exhibiting a much more limited interfacial structure compared to the [C4mpyr][dca] at almost all of the tested conditions. (3) For the [C4mpyr][dca]-based samples, without added zinc salt, the number of detected interfacial layers increases with negative potential. With added zinc, the [C4mpyr][dca] sample shows about the same number of layers independent of the applied potentials, namely between 5-7. Likewise, for the [C2mim][dca] samples, with the zinc added the sample shows the same number of layers at the applied potentials, but for this system only 1-2 layers are detected. And (4) the addition of Zn(dca)2 into the [C2mim][dca] IL does not cause a large change in the interfacial ordering, whereas the addition of the same salt into the [C4mpyr][dca] samples is marked by a stark increase in both the number and the consistency of the perceived interfacial layers. These results are significant because they show a marked difference in the interfacial nanostructure between two zinc-based electrochemical systems that were previously shown to have distinctly different electrochemical behaviour, despite their chemical similarity.
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2016 |
Chen Z, McLean B, Ludwig M, Stefanovic R, Warr GG, Webber GB, et al., 'Nanostructure of Deep Eutectic Solvents at Graphite Electrode Interfaces as a Function of Potential', Journal of Physical Chemistry C, 120 2225-2233 (2016) [C1]
© 2016 American Chemical Society. Atomic force microscopy (AFM), density functional theory (DFT) calculations, and contact angle measurements have been used to investigate the liq... [more]
© 2016 American Chemical Society. Atomic force microscopy (AFM), density functional theory (DFT) calculations, and contact angle measurements have been used to investigate the liquid-highly ordered pyrolytic graphite (HOPG) electrode interface for three deep eutectic solvents (DESs) as a function of applied potential. The DESs examined are 1:2 mixtures of choline chloride and urea (ChCl:urea), choline chloride and ethylene glycol (ChCl:ethylene glycol), and choline chloride and glycerol (ChCl:glycerol). DFT calculations reveal that in all cases the molecular component is excluded from the graphite interface at all potentials, while chloride and choline are attracted into the Stern layer at positive and negative potentials, respectively. AFM force curves confirm these trends and also show that the first near surface liquid layer in contact with the Stern layer is rich in the molecular component. The extent of near surface layering increases with potential and the hydrogen bonding capacity of the molecular component. The variation in the macroscopic contact angle with potential is consistent with changes in the Stern layer composition.
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2016 |
Wang Z, Li H, Atkin R, Priest C, 'Influence of Water on the Interfacial Nanostructure and Wetting of [Rmim][NTf2] Ionic Liquids at Mica Surfaces', Langmuir, 32 8818-8825 (2016) [C1]
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2016 |
Elbourne A, McLean B, Voitchovsky K, Warr GG, Atkin R, 'Molecular Resolution in situ Imaging of Spontaneous Graphene Exfoliation', JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 7 3118-3122 (2016) [C1]
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2016 |
Dolan DA, Sherman DA, Atkin R, Warr GG, 'Back Cover: Kamlet Taft Solvation Parameters of Solvate Ionic Liquids (ChemPhysChem 19/2016)', ChemPhysChem, 17 3147 (2016)
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2016 |
Carstens T, Ispas A, Borisenko N, Atkin R, Bund A, Endres F, 'In situ scanning tunneling microscopy (STM), atomic force microscopy (AFM) and quartz crystal microbalance (EQCM) studies of the electrochemical deposition of tantalum in two different ionic liquids with the 1-butyl-1-methylpyrrolidinium cation', Electrochimica Acta, 197 374-387 (2016) [C1]
© 2015 Elsevier Ltd. All rights reserved. The electrochemical reduction of 0.1 M TaF5 in two hydrophobic ionic liquids (1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) triflu... [more]
© 2015 Elsevier Ltd. All rights reserved. The electrochemical reduction of 0.1 M TaF5 in two hydrophobic ionic liquids (1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate ([Py1,4]FAP) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) amide ([Py1,4]TFSA) is probed using three in situ techniques: scanning tunneling microscopy (STM), atomic force microscopy (AFM), and electrochemical quartz crystal microbalance (EQCM). These techniques reveal that under similar conditions TaF5 is more easily reduced in the liquids with [TFSA]- than [FAP]-anions. Increasing the temperature reduced the viscosity and density of the ionic liquids which facilitates TaF5 electroreduction, in particular, in [Py1,4]TFSA. A herringbone reconstruction of the Au electrode was observed by STM for both ionic liquids with and without TaF5. Ta deposition was proved by STM and EQCM in [Py1,4]TFSA. Cracked layers, with ionic liquid trapped inside, were obtained by direct plating from the [TFSA]- ionic liquid. No Ta containing deposits could be obtained in the liquid with the [FAP]- anion.
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2016 |
Chen Z, McDonald S, Fitzgerald PA, Warr GG, Atkin R, 'Structural effect of glyme-Li+ salt solvate ionic liquids on the conformation of poly(ethylene oxide)', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 18 14894-14903 (2016) [C1]
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2016 |
Bryant SJ, Atkin R, Warr GG, 'Spontaneous vesicle formation in a deep eutectic solvent', Soft Matter, 12 1645-1648 (2016) [C1]
© The Royal Society of Chemistry 2016. Solvent penetration experiments and small-angle X-ray scattering reveal that phospholipids dissolved in a deep eutectic solvent (DES) sponta... [more]
© The Royal Society of Chemistry 2016. Solvent penetration experiments and small-angle X-ray scattering reveal that phospholipids dissolved in a deep eutectic solvent (DES) spontaneously self-assemble into vesicles above the lipid chain melting temperature. This means DESs are one of the few nonaqueous solvents that mediate amphiphile self-assembly, joining a select set of H-bonding molecular solvents and ionic liquids.
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2016 |
Li H, Somers AE, Rutland MW, Howlett PC, Atkin R, 'Combined Nano- and Macrotribology Studies of Titania Lubrication Using the Oil-Ionic Liquid Mixtures', ACS Sustainable Chemistry & Engineering, 4 5005-5012 (2016) [C1]
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2015 |
Chen Z, Fitzgerald PA, Kobayashi Y, Ueno K, Watanabe M, Warr GG, Atkin R, 'Micelle structure of novel diblock polyethers in water and two protic ionic liquids (EAN and PAN)', Macromolecules, 48 1843-1851 (2015) [C1]
© 2015 American Chemical Society. Small angle neutron scattering has been used to probe the self-assembled structures formed by novel block copolymers in water and two protic ioni... [more]
© 2015 American Chemical Society. Small angle neutron scattering has been used to probe the self-assembled structures formed by novel block copolymers in water and two protic ionic liquids (ILs), ethylammonium nitrate (EAN) and propylammonium nitrate (PAN). The block copolymers consist of solvophilic poly(ethylene oxide) (PEO) tethered to either poly(ethyl glycidyl ether) (PEGE) or poly(glycidyl propyl ether) (PGPrE) solvophobic blocks. Four block copolymers (EGE109EO54, EGE113EO115, EGE104EO178, and GPrE98EO260) have been investigated between 10 and 100 °C, showing how aggregate structure changes with increasing the EO block length, by changing the insoluble block from EGE to the more bulky, hydrophobic GPrE block, and with temperature. EO solubility mainly depends on the hydrogen bond network density, and decreases in the order H2O, EAN, and then PAN. The solubility of the EGE and GPrE blocks decreases in the order PAN, EAN then water because the large apolar domain of PAN increase the solubility of the solvophobic blocks more effectively than the smaller apolar domains in EAN, and water, which is entirely hydrophilic; GPrE is less soluble than EGE because its larger size hinders solubilization in the IL apolar domains. Large disk-shaped structures were present for EGE109EO54 in all three solvents because short EO chains favor flat structures, while GPrE98EO260 formed spherical structures because long EO chains lead to curved aggregates. The aggregate structures of EGE113EO115 and EGE104EO178, which have intermediate EO chain lengths, varied depending on the solvent and the temperature. Solubilities also explain trends in critical micelle concentrations (cmc) and temperatures (cmt).
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2015 |
Cummings J, Shah K, Atkin R, Moghtaderi B, 'Physicochemical interactions of ionic liquids with coal; The viability of ionic liquids for pre-treatments in coal liquefaction', Fuel, 143 244-252 (2015) [C1]
Copyright © 2014 Published by Elsevier Ltd. All rights reserved. Three Australian sub-bituminous coals were treated with three different ionic liquids (ILs) at a temperature of 10... [more]
Copyright © 2014 Published by Elsevier Ltd. All rights reserved. Three Australian sub-bituminous coals were treated with three different ionic liquids (ILs) at a temperature of 100 °C. The thermal behaviour of these treated coals were compared against raw coals via pyrolysis experiments in a Thermogravimetric Analyser. Morphological comparisons were also made via Scanning Electron Microscopy. Among the studied ILs, 1-butyl-3-methylimidazolium chloride [Bmim][Cl] was found to perform the most consistently in being able to alter the thermal and morphological properties of most of the coals used. It is posited that this may be due to the large difference in charge density between the delocalised charge of the large bmim cation and the chloride anion which allows this IL to disrupt the cross linked network of coal. It was also found that the interactions of the ionic liquids are coal specific, for instance none of the ionic liquids were able to change the thermal properties of coal A. Moreover, the results indicated that among the studied coals, coal R showed the highest mass loss during pyrolysis in TGA and coal C showed the highest amount of swelling and fragmentation in SEM images. The results displayed in this study indicate that the potential for ionic liquids to be used as pre-treatments in coal liquefaction is promising. Crown
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2015 |
Elbourne A, Cronshaw S, Voïtchovsky K, Warr GG, Atkin R, 'Near surface properties of mixtures of propylammonium nitrate with n-alkanols 1. Nanostructure', Physical Chemistry Chemical Physics, 17 26621-26628 (2015) [C1]
This journal is © the Owner Societies. In situ amplitude modulated-atomic force microscopy (AM-AFM) has been used to probe the nanostructure of mixtures of propylammonium nitrate ... [more]
This journal is © the Owner Societies. In situ amplitude modulated-atomic force microscopy (AM-AFM) has been used to probe the nanostructure of mixtures of propylammonium nitrate (PAN) with n-alkanols near a mica surface. PAN is a protic ionic liquid (IL) which has a bicontinuous sponge-like nanostructure of polar and apolar domains in the bulk, which becomes flatter near a solid surface. Mixtures of PAN with 1-butanol, 1-octanol, and 1-dodecanol at 10-70 vol% n-alkanol have been examined, along with each pure n-alkanol, to reveal the effect of composition and n-alkanol chain length. At low concentrations the butanol simply swells the PAN near-surface nanostructure, but at higher concentrations the nanostructure fragments. Octanol and dodecanol first lower the preferred curvature of the PAN near-surface nanostructure because, unlike n-butanol, their alkyl chains are too long to be accommodated alongside the PAN cations. At higher concentrations, octanol and dodecanol self-assemble into n-alkanol rich aggregates in a PAN rich matrix. The concentration at which aggregation first becomes apparent decreases with n-alkanol chain length.
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2015 |
Sweeney J, Webber GB, Atkin R, 'Near surface properties of mixtures of propylammonium nitrate with n-alkanols 2. Nanotribology and fluid dynamics', Physical Chemistry Chemical Physics, 17 26629-26637 (2015) [C1]
This journal is © the Owner Societies. Colloid probe friction force microscopy (FFM) has been used to study the lubricity of propylammonium nitrate (PAN) mixed with n-alkanols con... [more]
This journal is © the Owner Societies. Colloid probe friction force microscopy (FFM) has been used to study the lubricity of propylammonium nitrate (PAN) mixed with n-alkanols confined between sliding silica and mica surfaces. Mixtures of PAN with butanol, hexanol, octanol and dodecanol were investigated for various n-alkanol volume fractions to elucidate the effect of n-alkanol hydrocarbon chain length and concentration on shear forces. For all n-alkanols friction decreases with n-alkanol vol%. The trends in friction reduction with n-alkanol vol% do not correlate with changes in the bulk phase viscosity or the near surface nanostructure, and colloid probe atomic force microscope (AFM) fluid dynamic measurements showed that none of the mixtures shear thin. Thus, the reduction in friction is attributed to the n-alkanol disrupting solvophobic interactions between boundary layer propylammonium ions adsorbed to the mica and near surface liquid layers. The lowest friction is obtained for pure dodecanol, which is attributed to the dodecanol forming a robust boundary layer. Friction for the other pure n-alkanols is higher because the lateral attractions between adsorbed n-alkanols are too weak to facilitate the formation of a strong boundary layer, commensurate with the decreased hydrocarbon chain length.
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2015 |
McDonald S, Wood JA, FitzGerald PA, Craig VSJ, Warr GG, Atkin R, 'Interfacial and bulk nanostructure of liquid polymer nanocomposites', Langmuir, 31 3763-3770 (2015) [C1]
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2015 |
Li H, Atkin R, Page AJ, 'Combined Friction Force Microscopy and Quantum Chemical Investigation of the Tribotronic Response at the Propylammonium Nitrate Graphite Interface', Physical Chemistry Chemical Physics, 17 16047-16052 (2015) [C1]
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2015 |
Elbourne A, McDonald S, Voïchovsky K, Endres F, Warr GG, Atkin R, 'Nanostructure of the Ionic Liquid-Graphite Stern Layer', ACS Nano, 9 7608-7620 (2015) [C1]
© 2015 American Chemical Society. Ionic liquids (ILs) are attractive solvents for devices such as lithium ion batteries and capacitors, but their uptake is limited, partially beca... [more]
© 2015 American Chemical Society. Ionic liquids (ILs) are attractive solvents for devices such as lithium ion batteries and capacitors, but their uptake is limited, partially because their Stern layer nanostructure is poorly understood compared to molecular solvents. Here, in situ amplitude-modulated atomic force microscopy has been used to reveal the Stern layer nanostructure of the 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIm TFSI)-HOPG (highly ordered pyrolytic graphite) interface with molecular resolution. The effect of applied surface potential and added 0.1 wt/wt % Li TFSI or EMIm Cl on ion arrangements is probed between ±1 V. For pure EMIm TFSI at open-circuit potential, well-defined rows are present on the surface formed by an anion-cation-cation-anion (A-C-C-A) unit cell adsorbed with like ions adjacent. As the surface potential is changed, the relative concentrations of cations and anions in the Stern layer respond, and markedly different lateral ion arrangements ensue. The changes in Stern layer structure at positive and negative potentials are not symmetrical due to the different surface affinities and packing constraints of cations and anions. For potentials outside ±0.4 V, images are featureless because the compositional variation within the layer is too small for the AFM tip to detect. This suggests that the Stern layer is highly enriched in either cations or anions (depending on the potential) oriented upright to the surface plane. When Li<sup>+</sup> or Cl<sup>-</sup> is present, some Stern layer ionic liquid cations or anions (respectively) are displaced, producing starkly different structures. The Stern layer structures elucidated here significantly enhance our understanding of the ionic liquid electrical double layer.
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2015 |
McLean B, Li H, Stefanovic R, Wood RJ, Webber GB, Ueno K, et al., 'Nanostructure of [Li (G4)] TFSI and [Li (G4)] NO 3 solvate ionic liquids at HOPG and Au (111) electrode interfaces as a function of potential', Physical Chemistry Chemical Physics, 17 325-333 (2015) [C1]
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2015 |
Chen Z, FitzGerald PA, Warr GG, Atkin R, 'Conformation of poly(ethylene oxide) dissolved in the solvate ionic liquid [Li(G4)]TFSI.', Phys Chem Chem Phys, 17 14872-14878 (2015) [C1]
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2015 |
Hjalmarsson N, Wallinder D, Glavatskih S, Atkin R, Aastrup T, Rutland MW, 'Weighing the surface charge of an ionic liquid', Nanoscale, 7 16039-16045 (2015) [C1]
© The Royal Society of Chemistry 2015. Electrochemical quartz crystal microbalance has been used to measure changes in the composition of the capacitive electrical double layer fo... [more]
© The Royal Society of Chemistry 2015. Electrochemical quartz crystal microbalance has been used to measure changes in the composition of the capacitive electrical double layer for 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)-trifluorophosphate, an ionic liquid, in contact with a gold electrode surface as a function of potential. The mass difference between the cation and anion means that the technique can effectively "weigh" the surface charge accurately with high temporal resolution. This reveals quantitatively how changing the potential alters the ratio of cations and anions associated with the electrode surface, and thus the charge per unit area, as well as the kinetics associated with these interfacial processes. The measurements reveal that it is diffusion of co-ions into the interfacial region rather than expulsion of counterions that controls the relaxation. The measured potential dependent double layer capacitance experimentally validates recent theoretical predictions for counterion overscreening (low potentials) and crowding (high potentials) at electrode surfaces. This new capacity to quantitatively measure ion composition is critical for ionic liquid applications ranging from batteries, capacitors and electrodeposition through to boundary layer structure in tribology, and more broadly provides new insight into interfacial processes in concentrated electrolyte solutions.
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2015 |
Wydro MJ, Warr GG, Atkin R, 'Amplitude-modulated atomic force microscopy reveals the near surface nanostructure of surfactant sponge (L(3)) and lamellar (L(a)) phases.', Langmuir, 31 5513-5520 (2015) [C1]
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2015 |
Lahiri A, Carstens T, Atkin R, Borisenko N, Endres F, 'In Situ Atomic Force Microscopic Studies of the Interfacial Multilayer Nanostructure of LiTFSI-[Py
© 2015 American Chemical Society. In this paper, we present results on the nanoscale interactions of LiTFSI-[Py1, 4]TFSI with Au(111) using cyclic voltammetry and atomic force mic... [more]
© 2015 American Chemical Society. In this paper, we present results on the nanoscale interactions of LiTFSI-[Py1, 4]TFSI with Au(111) using cyclic voltammetry and atomic force microscopy (AFM). Raman spectroscopy was used to understand the Li+ ion coordination with the TFSI- ion and showed that with increase in LiTFSI concentration in [Py1, 4]TFSI, the Li+ ion solvation structure significantly changes. Correspondingly, the force-distance profile in AFM revealed that at lower concentrations of LiTFSI (0.1 M) a multilayered structure is obtained. On increasing the concentration of LiTFSI (0.5 and 1 M), a significant decrease in the number of interfacial layers was observed. With change in the potential, the interfacial layers were found to vary with an increase in the force required to rupture the layers. The present study clearly shows that Li+ ions vary the ionic liquid/Au(111) interface and could provide insight into the interfacial processes in ionic liquid based lithium batteries.
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2015 |
Elbourne A, Voïtchovsky K, Warr GG, Atkin R, 'Ion structure controls ionic liquid near-surface and interfacial nanostructure', Chemical Science, 6 527-536 (2015) [C1]
© The Royal Society of Chemistry 2015. A unique, but unifying, feature of ionic liquids (ILs) is that they are nanostructured on the length scale of the ions; in many ILs well-def... [more]
© The Royal Society of Chemistry 2015. A unique, but unifying, feature of ionic liquids (ILs) is that they are nanostructured on the length scale of the ions; in many ILs well-defined polar and apolar domains exist and may percolate through the liquid. Near a surface the isotropic symmetry of the bulk structure is broken, resulting in different nanostructures which, until now, have only been studied indirectly. In this paper, in situ amplitude modulated atomic force microscopy (AM-AFM) has been used to resolve the 3-dimensional nanostructure of five protic ILs at and near the surface of mica. The surface and near surface structures are distinct and remarkably well-defined, but are very different from previously accepted descriptions. Interfacial nanostructure is strongly influenced by the registry between cations and the mica surface charge sites, whereas near surface nanostructure is sensitive to both cation and anion structure. Together these ILs reveal how interfacial nanostructure can be tuned through ion structure, informing "bottom-up" design and optimisation of ILs for diverse technologies including heterogeneous catalysis, lubrication, electrochemical processes, and nanofluids. This journal is
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2015 |
Chen Z, Kobayashi Y, Webber GB, Ueno K, Watanabe M, Warr GG, Atkin R, 'Adsorption of Polyether Block Copolymers at Silica-Water and Silica-Ethylammonium Nitrate Interfaces.', Langmuir, 31 7025-7031 (2015) [C1]
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2015 |
An H, Liu G, Atkin R, Craig VSJ, 'Surface Nanobubbles in Nonaqueous Media: Looking for Nanobubbles in DMSO, Formamide, Propylene Carbonate, Ethylammonium Nitrate, and Propylammonium Nitrate', ACS Nano, 9 7596-7607 (2015) [C1]
© 2015 American Chemical Society. Surface nanobubbles produced by supersaturation during the exchange of ethanol for water are routinely observed on hydrophobic surfaces, are stab... [more]
© 2015 American Chemical Society. Surface nanobubbles produced by supersaturation during the exchange of ethanol for water are routinely observed on hydrophobic surfaces, are stable for days, and have contact angles that are very much greater than observed macroscopically. Here, we test the hypothesis that nanobubbles can also be observed in nonaqueous solvents in order to ascertain if their anomalous lifetimes and contact angles are related to properties of the solvent. Nanobubbles were seen in the protic solvents formamide, ethylammonium nitrate, and propylammonium nitrate, but not in propylene carbonate or dimethyl sulfoxide. Solvents in which nanobubbles were observed exhibit a three-dimensional hydrogen-bonding network. Like in aqueous systems, the nanobubbles were stable for days and exhibited high contact angles (~165°).
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2015 |
Chen Z, FitzGerald PA, Warr GG, Atkin R, 'Conformation of poly(ethylene oxide) dissolved in the solvate ionic liquid [Li(G4)]TFSI', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 17 14872-14878 (2015)
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2015 |
Hayes R, Warr GG, Atkin R, 'Structure and Nanostructure in Ionic Liquids', Chemical Reviews, 115 6357-6426 (2015) [C1]
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2015 |
Cummings J, Kundu S, Tremain P, Moghtaderi B, Atkin R, Shah K, 'Investigations into Physicochemical Changes in Thermal Coals during Low-Temperature Ionic Liquid Treatment', Energy and Fuels, 29 7080-7088 (2015) [C1]
© 2015 American Chemical Society. Two Australian thermal coals were treated with four different ionic liquids (ILs) at temperatures as low as 100 °C. The ILs used were 1-butylpyri... [more]
© 2015 American Chemical Society. Two Australian thermal coals were treated with four different ionic liquids (ILs) at temperatures as low as 100 °C. The ILs used were 1-butylpyridinium chloride ([Bpyd][Cl]), 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCM]), 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), and 1-butyl-3-methylimidazolium tricyanomethanide ([Bmim][TCM]). Visual comparisons were made between the raw and IL-treated coals via optical microscopy. Changes in thermal behavior of these treated coals were compared against raw coals via pyrolysis experiments in a thermogravimetric analyzer (TGA). Changes in functional group composition in the treated coals were probed via Fourier transform infrared (FTIR) spectroscopy. The recovered ILs were also analyzed via FTIR and nuclear magnetic resonance (NMR) spectroscopies to observe any changes after recovery. Low-temperature IL treatment of each of the coals resulted in fragmentation and fracturing, reducing the average particle size. An increase in mass loss in the treated coals was also observed when compared to each raw coal, indicating an increase in lower molecular weight fragments after treatment. This was corroborated by a large increase in aliphatic hydrocarbons being observed in the treated coals, along with a decrease in oxygenated functional groups and mineral matter in one coal. The recovered ILs were shown to be unchanged by this treatment process, indicating their potential recyclability. These results indicate the potential for ILs to be implemented as solvent treatments for coal conversion processes.
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2015 |
Murphy T, Atkin R, Warr GG, 'Scattering from ionic liquids', Current Opinion in Colloid and Interface Science, 20 282-292 (2015) [C1]
© 2015. Research into the properties and applications of ionic liquids (ILs) has accelerated over the last few decades, driven principally by the advanced reaction kinetics and sp... [more]
© 2015. Research into the properties and applications of ionic liquids (ILs) has accelerated over the last few decades, driven principally by the advanced reaction kinetics and specificity they offered for synthesis and catalysis. ILs display many highly desirable properties, including high electrical and thermal conductivities and wide electrochemical windows, all of which can be tuned by altering the nature of their constituent ions. The discovery that ILs mediate surfactant self-assembly increased interest further. X-ray and neutron scattering are powerful tools for elucidating structure in both simple and complex, mesostructured liquids that were soon applied to IL-based systems. Early work revealed that many IL solvents are themselves nanostructured, and comprise distinct polar and apolar domains produced by the solvophobic segregation of alkyl moieties. Over the last decade scattering techniques have been used to characterise the nanostructure of a diverse range of ILs. Recently, nanostructure changes in ILs produced by the dissolution of salts, polymers, small molecules and amphiphiles have begun to be elucidated. X-ray and neutron scattering have, and will continue to, play a fundamental role in understanding structure-property relationships in IL-based systems.
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2015 |
Shimizu K, Freitas AA, Atkin R, Warr GG, FitzGerald PA, Doi H, et al., 'Structural and aggregate analyses of (Li salt + glyme) mixtures: The complex nature of solvate ionic liquids', Physical Chemistry Chemical Physics, 17 22321-22335 (2015) [C1]
© the Owner Societies 2015. The structure and interactions of different (Li salt + glyme) mixtures, namely equimolar mixtures of lithium bis(trifluoromethylsulfonyl)imide, nitrate... [more]
© the Owner Societies 2015. The structure and interactions of different (Li salt + glyme) mixtures, namely equimolar mixtures of lithium bis(trifluoromethylsulfonyl)imide, nitrate or trifluoroacetate salts combined with either triglyme or tetraglyme molecules, are probed using Molecular Dynamics simulations. structure factor functions, calculated from the MD trajectories, confirmed the presence of different amounts of lithium-glyme solvates in the aforementioned systems. The MD results are corroborated by S(q) functions derived from diffraction and scattering data (HEXRD and SAXS/WAXS). The competition between the glyme molecules and the salt anions for the coordination to the lithium cations is quantified by comprehensive aggregate analyses. Lithium-glyme solvates are dominant in the lithium bis(trifluoromethylsulfonyl)imide systems and much less so in systems based on the other two salts. The aggregation studies also emphasize the existence of complex coordination patterns between the different species (cations, anions, glyme molecules) present in the studied fluid media. The analysis of such complex behavior is extended to the conformational landscape of the anions and glyme molecules and to the dynamics (solvate diffusion) of the bis(trifluoromethylsulfonyl)imide plus triglyme system.
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2015 |
Dolan A, Atkin R, Warr GG, 'The origin of surfactant amphiphilicity and self-assembly in protic ionic liquids', Chemical Science, 6 6189-6198 (2015) [C1]
© 2015 The Royal Society of Chemistry. The nature of amphiphilic self-assembly in alkylammonium protic ionic liquids (PILs) is examined by systematically varying the ionic structu... [more]
© 2015 The Royal Society of Chemistry. The nature of amphiphilic self-assembly in alkylammonium protic ionic liquids (PILs) is examined by systematically varying the ionic structure and composition, H-bonding capacity, and nanostructure of both the PIL and micelle-forming cationic surfactant, and contrasted with self-assembly in water. Using small-angle neutron scattering, micelle structure and concentrations are determined for primary-quaternary dodecylammonium salts in nitrate and thiocyanate PILs. While the solvophobic driving force depends only on the average polarity of the PIL, surprisingly strong, specific interactions of the head group and counterion with the PIL H-bond network are found. This suggests the importance of developing designer amphiphiles for assembling soft matter structures in PILs.
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2014 |
Jiang HJ, FitzGerald PA, Dolan A, Atkin R, Warr GG, 'Amphiphilic self-assembly of alkanols in protic ionic liquids.', J Phys Chem B, 118 9983-9990 (2014) [C1]
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2014 |
Page AJ, Elbourne A, Stefanovic R, Addicoat MA, Warr GG, Voïtchovsky K, Atkin R, '3-Dimensional atomic scale structure of the ionic liquid-graphite interface elucidated by AM-AFM and quantum chemical simulations.', Nanoscale, 6 8100-8106 (2014) [C1]
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2014 |
Hayes R, Imberti S, Warr GG, Atkin R, 'Effect of Cation Alkyl Chain Length and Anion Type on Protic Ionic Liquid Nanostructure', JOURNAL OF PHYSICAL CHEMISTRY C, 118 13998-14008 (2014) [C1]
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2014 |
Sweeney J, Webber GB, Rutland MW, Atkin R, 'Effect of ion structure on nanoscale friction in protic ionic liquids.', Phys Chem Chem Phys, 16 16651-16658 (2014) [C1]
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2014 |
Shah K, Atkin R, Stanger R, Wall T, Moghtaderi B, 'Interactions between vitrinite and inertinite-rich coals and the ionic liquid - [bmim][Cl]', Fuel, 119 214-218 (2014) [C1]
The interactions between vitrinite and inertinite-rich coals and the ionic liquid butylimidazolium chloride ([bmim][Cl]) heated to 100 C have been characterised. Differences in th... [more]
The interactions between vitrinite and inertinite-rich coals and the ionic liquid butylimidazolium chloride ([bmim][Cl]) heated to 100 C have been characterised. Differences in the interactions of coal macerals and ionic liquids have been identified. [bmim][Cl] is able to dissolve 22 wt% of a high-vitrinite coal fraction compared to 14 wt% of a high-inertinite coal fraction. The vitrinite-rich coal fraction tends to swell to a greater extent compared to the inertinite-rich coal fraction, which was fractured and fragmented rather than swelled. © 2013 Published by Elsevier Ltd. All rights reserved.
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2014 |
Smith JA, Webber GB, Warr GG, Zimmer A, Atkin R, Werzer O, 'Shear dependent viscosity of poly(ethylene oxide) in two protic ionic liquids', Journal of Colloid and Interface Science, 430 56-60 (2014) [C1]
Steady shear viscosity measurements have been performed on 100. kDa poly(ethylene oxide) (PEO) dissolved in the protic ionic liquids ethylammonium nitrate (EAN) and propylammonium... [more]
Steady shear viscosity measurements have been performed on 100. kDa poly(ethylene oxide) (PEO) dissolved in the protic ionic liquids ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) and in water. The zero shear viscosity in all three solvents increases with polymer concentration, falling into three concentration regimes corresponding to dilute, semi-dilute and network solutions. Huggins plots reveal three distinct solvent conditions: good (water), good-theta (EAN) and theta (PAN). However, differences in the transition concentrations, power law behaviour of the viscosities, and relaxation times arising from shear thinning in the two ILs can be directly related to the effects of solvent nanostructure. © 2014 Elsevier Inc.
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2014 |
Borisenko N, Atkin R, Lahiri A, El Abedin SZ, Endres F, 'Effect of dissolved LiCl on the ionic liquid-Au(111) interface: an in situ STM study', JOURNAL OF PHYSICS-CONDENSED MATTER, 26 (2014) [C1]
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2014 |
Li H, Wood RJ, Endres F, Atkin R, 'Influence of alkyl chain length and anion species on ionic liquid structure at the graphite interface as a function of applied potential', Journal of Physics Condensed Matter, 26 (2014) [C1]
Atomic force microscopy (AFM) force measurements elucidate the effect of cation alkyl chain length and the anion species on ionic liquid (IL) interfacial structure at highly order... [more]
Atomic force microscopy (AFM) force measurements elucidate the effect of cation alkyl chain length and the anion species on ionic liquid (IL) interfacial structure at highly ordered pyrolytic graphite (HOPG) surfaces as a function of potential. Three ILs are examined: 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([HMIM] FAP), 1-ethyl-3- methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([EMIM] FAP), and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM] TFSA). The step-wise force-distance profiles indicate the ILs adopt a multilayered morphology near the surface. When the surface is biased positively or negatively versus Pt quasireference electrode, both the number of steps, and the force required to rupture each step increase, indicating stronger interfacial structure. At all potentials, push-through forces for [HMIM] FAP are the highest, because the long alkyl chain results in strong cohesive interactions between cations, leading to well-formed layers that resist the AFM tip. The most layers are observed for [EMIM] FAP, because the C2 chains are relatively rigid and the dimensions of the cation and anion are similar, facilitating neat packing. [EMIM] TFSA has the smallest push-through forces and fewest layers, and thus the weakest interfacial structure. Surface-tip attractive forces are measured for all ILs. At the same potential, the attractions are the strongest for [EMIM] TFSA and the weakest for [HMIM] FAP because the interfacial layers are better formed for the longer alkyl chain cation. This means interfacial forces are stronger, which masks the weak attractive forces. © 2014 IOP Publishing Ltd.
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2014 |
Li H, Cooper PK, Somers AE, Rutland MW, Howlett PC, Forsyth M, Atkin R, 'Ionic liquid adsorption and nanotribology at the silica-oil interface: Hundred-fold dilution in oil lubricates as effectively as the pure ionic liquid', Journal of Physical Chemistry Letters, 5 4095-4099 (2014) [C1]
© 2014 American Chemical Society. The remarkable physical properties of ionic liquids (ILs) make them potentially excellent lubricants. One of the challenges for using ILs as lubr... [more]
© 2014 American Chemical Society. The remarkable physical properties of ionic liquids (ILs) make them potentially excellent lubricants. One of the challenges for using ILs as lubricants is their high cost. In this article, atomic force microscopy (AFM) nanotribology measurements reveal that a 1 mol % solution of IL dissolved in an oil lubricates the silica surface as effectively as the pure IL. The adsorption isotherm shows that the IL surface excess need only be approximately half of the saturation value to prevent surface contact and effectively lubricate the sliding surfaces. Using ILs in this way makes them viable for large-scale applications.
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2014 |
Borisenko N, Atkin R, Endres F, 'Influence of molecular organization of ionic liquids on electrochemical properties', Electrochemical Society Interface, 23 59-63 (2014) [C2]
Ionic liquids (IL) exhibit a remarkably diverse interfacial chemistry, with multiple interfacial layers present at the IL/solid interface. Ionic liquids (ILs) are pure salts with ... [more]
Ionic liquids (IL) exhibit a remarkably diverse interfacial chemistry, with multiple interfacial layers present at the IL/solid interface. Ionic liquids (ILs) are pure salts with melting points typically less than 100°C. It has remarkable physical properties, which include wide electrochemical stability windows, high ionic conductivity and negligible vapor pressure. The adsorption strength of ILs onto solid surfaces is much higher than for typical organic solvents or water. The structure and composition of the interfacial layer can be tuned by varying the surface potential and the ionic structure, and by addition of solutes. This allows us to envision that IL interfacial properties can be readily matched to a particular application once the required fundamental understanding is elucidated. STM and AFM results show that the IL cation has a strong influence on the structure and composition of the interface.
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2014 |
Murphy T, Hayes R, Imberti S, Warr GG, Atkin R, 'Nanostructure of an ionic liquid-glycerol mixture', Physical Chemistry Chemical Physics, 16 13182-13190 (2014) [C1]
The nanostructure of a 50:50 vol% mixture of glycerol and ethylammonium formate (EAF), a protic ionic liquid (IL), has been investigated using neutron diffraction and empirical po... [more]
The nanostructure of a 50:50 vol% mixture of glycerol and ethylammonium formate (EAF), a protic ionic liquid (IL), has been investigated using neutron diffraction and empirical potential structure refinement (EPSR) fits. EPSR fits reveal that the mixture is nanostructured. Electrostatic interactions between IL charge groups leads to the formation of ionic regions. These solvophobically repel cation alkyl groups which cluster together to form apolar domains. The polar glycerol molecules are preferentially incorporated into the charged domains, and form hydrogen bonds with EAF groups rather than with other glycerol molecules. However, radial distribution functions reveal that glycerol molecules pack around each other in a fashion similar to that found in pure glycerol. This suggests that a glycerol channel runs through the ionic domain of EAF. The absence of significant glycerol-glycerol hydrogen bonding indicates that glycerol molecules are able to span the polar domain, bridging EAF charge groups. Glycerol can adopt six distinct conformations. The distribution of conformers in the EAF mixture is very different to that found in the pure liquid because hydrogen bonds form with EAF rather than with other glycerol molecules, which imparts different packing constraints. © 2014 The Owner Societies.
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2014 |
Murphy T, Varela LM, Webber GB, Warr GG, Atkin R, 'Nanostructure-thermal conductivity relationships in protic ionic liquids', Journal of Physical Chemistry B, 118 12017-12024 (2014) [C1]
© 2014 American Chemical Society. The thermal conductivities of nine protic ionic liquids (ILs) have been investigated between 293 and 340 K. Within this range, the thermal conduc... [more]
© 2014 American Chemical Society. The thermal conductivities of nine protic ionic liquids (ILs) have been investigated between 293 and 340 K. Within this range, the thermal conductivities are between 0.18 and 0.30 W·m-1·K-1. These values are higher than those typically associated with oils and aprotic ILs, but lower than those of strongly hydrogen bonding solvents like water. Weak linear decreases in thermal conductivity with temperature are noted, with the exception of ethanolammonium nitrate (EtAN) where the thermal conductivity increases with temperature. The dependence of thermal conductivity on IL type is analyzed with use of the Bahe-Varela pseudolattice theory. This theory treats the bulk IL as an array of ordered domains with intervening domains of uncorrelated structure which enable and provide barriers to heat propagation (respectively) via allowed vibrational modes. For the protic ILs investigated, thermal conductivity depends strongly on the IL cation alkyl chain length. This is because the cation alkyl chain controls the dimensions of the IL bulk nanostructure, which consists of charged (ordered domains) and uncharged regions (disordered domains). As the cation alkyl chain controls the dimensions of the disordered domains, it thus limits the thermal conductivity. To test the generality of this interpretation, the thermal conductivities of propylammonium nitrate (PAN) and PAN-octanol mixtures were examined; water selectively swells the PAN charged domain, while octanol swells the uncharged regions. Up to a certain concentration, adding water increases thermal conduction and octanol decreases it, as expected. However, at high solute concentrations the IL nanostructure is broken. When additional solvent is added above this concentration the rate of change in thermal conductivity is greatly reduced. This is because, in the absence of nanostructure, the added solvent only serves to dilute the salt solution.
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2014 |
Addicoat MA, Stefanovic R, Webber GB, Atkin R, Page AJ, 'Assessment of the density functional tight binding method for protic ionic liquids', Journal of Chemical Theory and Computation, 10 4633-4643 (2014) [C1]
© 2014 American Chemical Society. Density functional tight binding (DFTB), which is ~100-1000 times faster than full density functional theory (DFT), has been used to simulate the... [more]
© 2014 American Chemical Society. Density functional tight binding (DFTB), which is ~100-1000 times faster than full density functional theory (DFT), has been used to simulate the structure and properties of protic ionic liquid (IL) ions, clusters of ions and the bulk liquid. Proton affinities for a wide range of IL cations and anions determined using DFTB generally reproduce G3B3 values to within 5-10 kcal/mol. The structures and thermodynamic stabilities of n-alkyl ammonium nitrate clusters (up to 450 quantum chemical atoms) predicted with DFTB are in excellent agreement with those determined using DFT. The IL bulk structure simulated using DFTB with periodic boundary conditions is in excellent agreement with published neutron diffraction data.
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2014 |
Hayes R, Bernard SA, Imberti S, Warr GG, Atkin R, 'Solvation of Inorganic Nitrate Salts in Protic Ionic Liquids', JOURNAL OF PHYSICAL CHEMISTRY C, 118 21215-21225 (2014) [C1]
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2014 |
Carstens T, Gustus R, Höfft O, Borisenko N, Endres F, Li H, et al., 'Combined STM, AFM, and DFT study of the highly ordered pyrolytic graphite/1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide interface', Journal of Physical Chemistry C, 118 10833-10843 (2014) [C1]
The highly ordered pyrolytic graphite (HOPG)/1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIm]Tf2N) interface is examined by ultrahigh vacuum scanning tunnelin... [more]
The highly ordered pyrolytic graphite (HOPG)/1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIm]Tf2N) interface is examined by ultrahigh vacuum scanning tunneling microscopy (UHV-STM), atomic force microscopy (UHV-AFM) (and as a function of potential by in situ scanning tunneling microscopy (STM)), in situ atomic force microscopy (AFM), and density functional theory (DFT) calculations. In situ STM and AFM results reveal that multiple ionic liquid (IL) layers are present at the HOPG/electrode interface at all potentials. At open-circuit potential (OCP), attractions between the cation alkyl chain and the HOPG surface result in the ion layer bound to the surface being cation rich. As the potential is varied, the relative concentrations of cations and anions in the surface layer change: as the potential is made more positive, anions are preferentially adsorbed at the surface, while at negative potentials the surface layer is cation rich. At -2 V an unusual overstructure forms. STM images and AFM friction force microscopy measurements both confirm that the roughness of this overstructure increases with time. DFT calculations reveal that [OMIm]+ is attracted to the graphite surface at OCP; however, adsorption is enhanced at negative potentials due to favorable electrostatic interactions, and at -2 V the surface layer is cation rich and strongly bound. The energetically most favorable orientation within this layer is with the [OMIm]+ octyl chains aligned "epitaxially" along the graphitic lattice. This induces quasi-crystallization of cations on the graphite surface and formation of the overstructure. An alternative explanation may be that, because of the bulkiness of the cation sitting along the surface, a single layer of cations is unable to quench the surface potential, so a second layer forms. The most energetically favorable way to do this might be in a quasi-crystalline/multilayered fashion. It could also be a combination of strong surface binding/orientations and the need for multilayers to quench the charge. © 2014 American Chemical Society.
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2014 |
Smith JA, Webber GB, Warr GG, Zimmer A, Atkin R, Werzer O, 'Shear dependent viscosity of poly(ethylene oxide) in two protic ionic liquids', JOURNAL OF COLLOID AND INTERFACE SCIENCE, 430 56-60 (2014)
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2014 |
Atkin R, Borisenko N, Drüschler M, Endres F, Hayes R, Huber B, Roling B, 'Structure and dynamics of the interfacial layer between ionic liquids and electrode materials', Journal of Molecular Liquids, 192 44-54 (2014) [C1]
In this overview paper we present a combined in situ STM, AFM and EIS study on the structure and dynamics of the interfacial layers between Au(111) and two extremely pure ionic li... [more]
In this overview paper we present a combined in situ STM, AFM and EIS study on the structure and dynamics of the interfacial layers between Au(111) and two extremely pure ionic liquids, namely [Py1,4]FAP and [EMIM]FAP. The combination of these methods provides valuable information for both neutral and electrified interfaces. In situ STM and AFM results reveal that a multilayered ion morphology is present at the IL-Au(111) interface, with stronger near surface layering detected at higher electrode potentials. The in situ STM measurements show that the structure of the interfacial layers is dependent on the applied electrode potential, the number of subsequent STM scans and the scan rate. Furthermore, in the case of [Py1,4]FAP, the Au(111) surface undergoes herringbone reconstruction, Au(111)(22×3), in the cathodic potential regime, and the ultra-slow formation of vacancies in the herringbone structure is probed with in situ STM. EIS measurements reveal the presence of two distinct capacitive processes at the interface taking place on different time scales. The time scale of the fast process is typically in the millisecond range and is governed by the bulk ion transport in the IL, which exhibits a Vogel-Fulcher-Tammann-type temperature dependence. The slow process takes place on a time scale of seconds and is Arrhenius activated. The contribution of this process to the overall interfacial capacitance is particularly large in the potential regime where the herringbone structure is probed. Furthermore, we analyze the temperature dependence of the interfacial capacitance. © 2013 Elsevier B.V. All rights reserved.
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2014 |
Smith J, Webber GB, Warr GG, Atkin R, 'Silica particle stability and settling in protic ionic liquids', Langmuir, 30 1506-1513 (2014) [C1]
Silica particle suspensions of 10 wt % have been investigated in the protic ionic liquids (ILs) ethylammonium nitrate (EAN), ethanolammonium nitrate (EtAN), propylammonium nitrate... [more]
Silica particle suspensions of 10 wt % have been investigated in the protic ionic liquids (ILs) ethylammonium nitrate (EAN), ethanolammonium nitrate (EtAN), propylammonium nitrate (PAN), and dimethylethylammonium formate (DMEAF). Static and dynamic light scattering reveal that single particles coexist in dynamic equilibrium with flocculated networks at room temperature. These types of systems are classified as weakly flocculated and are quite rare. As weakly flocculated systems generally exist only within a narrow range of conditions, the effect of temperature was probed. When temperature is increased, the thermal motion of suspended particles increases, favoring dispersion, but in ILs suspensions, heating reduces the stabilizing effect of the interfacial structure of the IL. When subjected to a small increase in temperature, particle suspensions in ILs become unstable, indicated by the absence of a peak corresponding to single particles in the light scattering data. For EAN and DMEAF, further increasing temperatures above 40 C returns the systems to a weakly flocculated state in which thermal energy is sufficient to break particles away from aggregates. Weakly flocculated suspensions in EAN and EtAN settle more rapidly than predicted by the Stokes equation, as the particles spend a significant portion of time in large, rapidly settling flocs. Surprisingly, suspensions in PAN and DMEAF settle slower than predicted. Oscillatory rheology indicates that these suspensions are viscoelastic, due to a persistent, long-range structure in the suspension that slows settling. In aggregated systems, settling is very rapid. © 2014 American Chemical Society.
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2014 |
Topolnicki IL, Fitzgerald PA, Atkin R, Warr GG, 'Effect of protic ionic liquid and surfactant structure on partitioning of polyoxyethylene non-ionic surfactants', ChemPhysChem, 15 2485-2489 (2014) [C1]
The partitioning constants and Gibbs free energies of transfer of poly(oxyethylene) n-alkyl ethers between dodecane and the protic ionic liquids (ILs) ethylammonium nitrate (EAN) ... [more]
The partitioning constants and Gibbs free energies of transfer of poly(oxyethylene) n-alkyl ethers between dodecane and the protic ionic liquids (ILs) ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) are determined. EAN and PAN have a sponge-like nanostructure that consists of interpenetrating charged and apolar domains. This study reveals that the ILs solvate the hydrophobic and hydrophilic parts of the amphiphiles differently. The ethoxy groups are dissolved in the polar region of both ILs by means of hydrogen bonds. The environment is remarkably water-like and, as in water, the solubility of the ethoxy groups in EAN decreases on warming, which underscores the critical role of the IL hydrogen-bond network for solubility. In contrast, amphiphile alkyl chains are not preferentially solvated by the charged or uncharged regions of the ILs. Rather, they experience an average IL composition and, as a result, partitioning from dodecane into the IL increases as the cation alkyl chain is lengthened from ethyl to propyl, because the IL apolar volume fraction increases. Together, these results show that surfactant dissolution in ILs is related to structural compatibility between the head or tail group and the IL nanostructure. Thus, these partitioning studies reveal parameters for the effective molecular design of surfactants in ILs. Surfactants in ionic liquids: The dissolution and solvation of the hydrophilic and hydrophobic components of non-ionic surfactants in ionic liquids are affected by solvent nanostructure and hydrogen bonding. The polar domains of protic ionic liquids ethyl- and propylammonium nitrate are, thermodynamically speaking, remarkably water-like. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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2014 |
Li H, Wood RJ, Rutland MW, Atkin R, 'An ionic liquid lubricant enables superlubricity to be "switched on" in situ using an electrical potential.', Chem Commun (Camb), 50 4368-4370 (2014) [C1]
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2013 |
Elbourne A, Sweeney J, Webber GB, Wanless EJ, Warr GG, Rutland MW, Atkin R, 'Adsorbed and near-surface structure of ionic liquids determines nanoscale friction', CHEMICAL COMMUNICATIONS, 49 6797-6799 (2013) [C1]
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2013 |
Hayes R, Imberti S, Warr GG, Atkin R, 'The Nature of Hydrogen Bonding in Protic Ionic Liquids', ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 52 4623-4627 (2013) [C1]
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2013 |
Li H, Rutland MW, Atkin R, 'Ionic liquid lubrication: Influence of ion structure, surface potential and sliding velocity', Physical Chemistry Chemical Physics, 15 14616-14623 (2013) [C1]
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2013 |
Segura JJ, Voïtchovsky K, Elbourne A, Wanless EJ, Warr GG, Atkin R, 'Adsorbed and near surface structure of ionic liquids at a solid interface', Physical Chemistry Chemical Physics, 15 3320-3328 (2013) [C1]
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2013 |
Li H, Endres F, Atkin R, 'Effect of alkyl chain length and anion species on the interfacial nanostructure of ionic liquids at the Au(111)-ionic liquid interface as a function of potential', Physical Chemistry Chemical Physics, 15 14624-14633 (2013) [C1]
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2013 |
Smith JA, Webber GB, Warr GG, Atkin R, 'Rheology of Protic Ionic Liquids and Their Mixtures', JOURNAL OF PHYSICAL CHEMISTRY B, 117 13930-13935 (2013) [C1]
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2013 |
Sharma SC, Atkin R, Warr GG, 'The Effect of Ionic Liquid Hydrophobicity and Solvent Miscibility on Pluronic Amphiphile Self-Assembly', The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces and Biophysical, 117 14568-14575 (2013) [C1]
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2013 |
Hayes R, Imberti S, Warr GG, Atkin R, 'The Nature of Hydrogen Bonding in Protic Ionic Liquids', Angewandte Chemie, 125 4721-4725 (2013) [C1]
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2012 |
Wakeham D, Eschebach DS, Webber GB, Atkin R, Warr GG, 'Surface composition of mixtures of ethylammonium nitrate, ethanolammonium nitrate, and water', Australian Journal of Chemistry, 65 1554-1556 (2012) [C1]
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2012 |
Carstens T, Hayes RL, Abedin SZE, Corr BJ, Webber GB, Borisenko N, et al., 'In situ STM, AFM and DTS study of the interface 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate/Au(1 1 1)', Electrochimica Acta, 82 48-59 (2012) [C1]
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2012 |
Sweeney JT, Hausen F, Hayes RL, Webber GB, Endres F, Rutland MW, et al., 'Control of nanoscale friction on gold in an ionic liquid by a potential-dependent ionic lubricant layer', Physical Review Letters, 109 155502 (2012) [C1]
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2012 |
Asencio RA, Cranston ED, Atkin R, Rutland MW, 'Ionic liquid nanotribology: Stiction suppression and surface induced shear thinning', Langmuir, 28 9967-9976 (2012) [C1]
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2012 |
Wakeham D, Warr GG, Atkin R, 'Surfactant adsorption at the surface of mixed ionic liquids and ionic liquid water mixtures', Langmuir, 28 13224-13231 (2012) [C1]
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2012 |
Endres F, Borisenko N, El Abedin SZ, Hayes RL, Atkin R, 'The interface ionic liquid(s)/electrode(s): In situ STM and AFM measurements', Faraday Discussions, 154 221-233 (2012) [C1]
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2012 |
Hayes RL, Borisenko N, Corr BJ, Webber GB, Endres F, Atkin R, 'Effect of dissolved LiCl on the ionic liquid-Au(111) electrical double layer structure', Chemical Communications, 48 10246-10248 (2012) [C1]
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2012 |
Hayes RL, Imberti S, Warr GG, Atkin R, 'How water dissolves in protic ionic liquids', Angewandte Chemie - International Edition, 51 7468-7471 (2012) [C1]
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2012 |
Wakeham D, Niga P, Ridings C, Andersson G, Nelson A, Warr GG, et al., 'Surface structure of a 'non-amphiphilic' protic ionic liquid', Physical Chemistry Chemical Physics, 14 5106-5114 (2012) [C1]
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2012 |
Werzer O, Cranston ED, Warr GG, Atkin R, Rutland MW, 'Ionic liquid nanotribology: mica-silica interactions in ethylammonium nitrate', Physical Chemistry Chemical Physics, 14 5147-5152 (2012) [C1]
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2011 |
Werzer O, Warr GG, Atkin R, 'Conformation of poly(ethylene oxide) dissolved in ethylammonium nitrate', Journal of Physical Chemistry B, 115 648-652 (2011) [C1]
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2011 |
Hayes RL, Borisenko N, Tam MK, Howlett PC, Endres F, Atkin R, 'Double layer structure of ionic liquids at the Au(111) electrode interface: An atomic force microscopy investigation', Journal of Physical Chemistry C, 115 6855-6863 (2011) [C1]
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2011 |
Werzer O, Warr GG, Atkin R, 'Compact poly(ethylene oxide) structures adsorbed at the ethylammonium nitrate-silica interface', Langmuir, 27 3541-3549 (2011) [C1]
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2011 |
Werzer O, Atkin R, 'Interactions of adsorbed poly(ethylene oxide) mushrooms with a bare silica-ionic liquid interface', Physical Chemistry Chemical Physics, 13 13479-13485 (2011) [C1]
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2011 |
Hayes RL, Imberti S, Warr GG, Atkin R, 'Amphiphilicity determines nanostructure in protic ionic liquids', Physical Chemistry Chemical Physics, 13 3237-3247 (2011) [C1]
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2011 |
Hayes RL, Imberti S, Warr GG, Atkin R, 'Pronounced sponge-like nanostructure in propylammonium nitrate', Physical Chemistry Chemical Physics, 13 13544-13551 (2011) [C1]
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2011 |
Atkin R, Borisenko N, Druschler M, El Abedin SZ, Endres F, Hayes RL, et al., 'An in situ STM/AFM and impedance spectroscopy study of the extremely pure 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate/Au(111) interface: Potential dependent solvation layers and the herringbone reconstruction', Physical Chemistry Chemical Physics, 13 6849-6857 (2011) [C1]
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2011 |
Wakeham D, Nelson A, Warr GG, Atkin R, 'Probing the protic ionic liquid surface using X-ray reflectivity', Physical Chemistry Chemical Physics, 13 20828-20835 (2011) [C1]
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2010 |
Atkin R, Bobillier SMC, Warr GG, 'Propylammonium nitrate as a solvent for amphiphile self-assembly into micelles, lyotropic liquid crystals, and microemulsions', Journal of Physical Chemistry B, 114 1350-1360 (2010) [C1]
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2010 |
Smith JA, Werzer O, Webber GB, Warr GG, Atkin R, 'Surprising particle stability and rapid sedimentation rates in an ionic liquid', Journal of Physical Chemistry Letters, 1 64-68 (2010) [C1]
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2010 |
Endres F, 'Physical chemistry of ionic liquids.', Phys Chem Chem Phys, 12 1648 (2010)
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2010 |
Marquet PR, Andersson G, Snedden A, Kloo L, Atkin R, 'Molecular scale characterization of the titania-dye-solvent interface in dye-sensitized solar cells', Langmuir, 26 9612-9616 (2010) [C1]
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2010 |
Niga P, Wakeham D, Nelson A, Warr GG, Rutland M, Atkin R, 'Structure of the ethylammonium nitrate surface: An X-ray reflectivity and vibrational sum frequency spectroscopy study', Langmuir, 26 8282-8288 (2010) [C1]
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2010 |
Wakeham D, Niga P, Warr GG, Rutland MW, Atkin R, 'Nonionic surfactant adsorption at the ethylammonium nitrate surface: A neutron reflectivity and vibrational sum frequency spectroscopy study', Langmuir, 26 8313-8318 (2010) [C1]
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2010 |
Endres F, Hofft O, Borisenko N, Gasparotto LH, Prowald A, Al-Salman R, et al., 'Do solvation layers of ionic liquids influence electrochemical reactions?', Physical Chemistry Chemical Physics, 12 1724-1732 (2010) [C1]
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2010 |
Hayes RL, Warr GG, Atkin R, 'At the interface: Solvation and designing ionic liquids', Physical Chemistry Chemical Physics, 12 1709-1723 (2010) [C1]
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2009 |
Wakeham D, Hayes RL, Warr GG, Atkin R, 'Influence of temperature and molecular structure on ionic liquid solvation layers', Journal of Physical Chemistry B, 113 5961-5966 (2009) [C1]
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2009 |
Hayes RL, El Abedin SZ, Atkin R, 'Pronounced structure in confined aprotic room-temperature ionic liquids', Journal of Physical Chemistry B, 113 7049-7052 (2009) [C1]
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2009 |
Atkin R, De Fina L-M, Kiederling U, Warr GG, 'Structure and self assembly of pluronic amphiphiles in ethylammonium nitrate and at the silica surface', Journal of Physical Chemistry B, 113 12201-12213 (2009) [C1]
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2009 |
Atkin R, El Abedin SZ, Hayes RL, Gasparotto LHS, Borisenko N, Endres F, 'AFM and STM studies on the surface interaction of (BMP)TFSA and (EMIm)TFSA ionic liquids with Au(111)', Journal of Physical Chemistry C, 113 13266-13272 (2009) [C1]
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2009 |
Howard SC, Atkin R, Craig VSJ, 'Effect of electrolyte species on the adsorption of a cationic surfactant to silica: The common intersection point', Colloids and Surfaces A: Physicochemical and Engineering Aspects, 347 109-113 (2009) [C1]
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2009 |
Mann JP, McCluskey A, Atkin R, 'Activity and thermal stability of lysozyme in alkylammonium formate ionic liquids: Influence of cation modification', Green Chemistry, 11 785-792 (2009) [C1]
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2008 |
Atkin R, Warr GG, 'The smallest amphiphiles: Nanostructure in protic room-temperature ionic liquids with short alkyl groups', The Journal of Physical Chemistry. B, 112 4164-4166 (2008) [C1]
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2007 |
Atkin R, Warr GG, 'Structure in confined room-temperature ionic liquids', JOURNAL OF PHYSICAL CHEMISTRY C, 111 5162-5168 (2007) [C1]
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2007 |
Atkin R, Warr GG, 'Phase behavior and microstructure of microemulsions with a room-temperature ionic liquid as the polar phase', JOURNAL OF PHYSICAL CHEMISTRY B, 111 9309-9316 (2007) [C1]
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2006 |
Thordarson P, Atkin R, Kalle WHJ, Warr GG, Braet F, 'Developments in using scanning probe microscopy to study molecules on surfaces - From thin films and single-molecule conductivity to drug-living cell interactions', AUSTRALIAN JOURNAL OF CHEMISTRY, 59 359-375 (2006) [C1]
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2005 |
Atkin R, Warr GG, 'Self-assembly of a nonionic surfactant at the graphite/ionic liquid interface', JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 127 11940-11941 (2005) [C1]
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2005 |
Dowding PJ, Atkin R, Vincent B, Bouillot P, 'Oil core/polymer shell microcapsules by internal phase separation from emulsion droplets. II: Controlling the release profile of active molecules', LANGMUIR, 21 5278-5284 (2005) [C1]
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2005 |
Atkin R, Bradley M, Vincent B, 'Core-shell particles having silica cores and pH-responsive poly(vinylpyridine) shells', SOFT MATTER, 1 160-165 (2005) [C1]
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2004 |
Atkin R, Davies P, Hardy J, Vincent B, 'Preparation of aqueous core/polymer shell microcapsules by internal phase separation', MACROMOLECULES, 37 7979-7985 (2004) [C1]
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2004 |
Burnett GR, Atkin R, Hicks S, Eastoe J, 'Surfactant-free "Emulsions" generated by freeze-thaw', LANGMUIR, 20 5673-5678 (2004) [C1]
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2004 |
Dowding PJ, Atkin R, Vincent B, Bouillot P, 'Oil core-polymer shell microcapsules prepared by internal phase separation from emulsion droplets. I. Characterization and release rates for microcapsules with polystyrene shells', LANGMUIR, 20 11374-11379 (2004) [C1]
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2003 |
Atkin R, Craig VSJ, Wanless EJ, Biggs SR, 'Adsorption of 12-s-12 Gemini Surfactants at the Silica - Aqueous Solution Interface', Journal of Physical Chemistry Part B, 2978-2985 (2003) [C1]
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2003 |
Atkin R, Craig VSJ, Wanless EJ, Biggs SR, 'Mechanism of cationic surfactant adsorption at the solid-aqueous interface', Advances in Colloid and Interface Science, 219-304 (2003) [C1]
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2003 |
Atkin R, Craig VSJ, Wanless EJ, Biggs SR, 'The influence of chain length and electrolyte on the adsorption kinetics of cationic surfactants at the silica-aqueous solution interface', Journal of Colloid and Interface Science, 236-244 (2003) [C1]
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2003 |
Atkin R, Craig VSJ, Hartley PG, Wanless EJ, Biggs SR, 'Adsorption of Ionic Surfactants to a Plasma Polymer Substrate', Langmuir, 4222-4227 (2003) [C1]
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2001 |
Atkin R, Craig VSJ, Biggs SR, 'Adsorption kinetics and structural arrangements of cetylpyridinium bromide at the silica-aqueous interface', Langmuir, 17 6155-6163 (2001) [C1]
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2000 |
Atkin R, Craig VSJ, Biggs SR, 'Adsorption kinetics and structural arrangements of cationic surfactants on silica surfaces', Langmuir, 16 9374-9380 (2000) [C1]
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