Dr Hua Li
PRC Research Fellow
School of Environmental and Life Sciences
Science Fiction and the Science of Friction
A scientist improving the efficiency of machinery smaller than a human cell, whilst using salt to extract harmful gas from the air, may sound like the stuff of imagination, but Dr Hua Li is real and looking to change the world.
An early career researcher, Hua’s research interests centre on advanced industrial fluids. Her fluids of choice are Ionic liquids (ILs).
Composed of salt in a liquid state, ILs are solvent-free electrolytes with unique properties making them superior to conventional industrial lubricants, adsorbents, and solvents.
With negligible vapor pressure, high ionic conductivity, and high temperature stability, ILs are set to smash the current limitations of industry and take us directly to space.
As well as using ILs to develop high performance and cost-effective lubricants, Hua is aiming to reduce the impact of industry by utilising ILs as anthropogenic gas adsorbents.
Hua is a principal research member for the UON’s Priority Research Centre for Advanced Fluids And Interfaces.
“At the PRC, we aim to connect our research to industry, and we really hope to convert what we find in small scale for use in large-scale industry.”
Lubricity on any scale
From the largest machines involved in resource mining to the smallest nanoscale devices, friction is a constant consideration in the design and maintenance of machinery.
Lubricants are essential to reduce friction and wear in industrial applications.
“But it is very difficult to lubricate lightweight metal surfaces such as aluminum, and titanium,” Hua explains.
“As a result, high density metals that cost a lot of energy, such as iron and steel are still used in industry as moving parts.”
“We are aiming to change that.”
Nanoscale devices working on an atomic or molecular level come with their own set of challenges regarding wear, friction, and heat.
“Linking tribological performance at the nanoscale and macroscale remains a considerable challenge for the development of new and more effective lubricants,” Hua explains.
Cost is another factor.
“ILs have proven to reduce friction but are quite expensive,” Hua says.
“So instead of replacing common lubricant oils, we are working on dissolving ILs into conventional lubricants.”
But the addition of just how much Ionic liquid is needed to alter lubricity?
“Even by adding one percent ILs, the lubricity significantly improves, so our work in that area is very promising,” Hua states.
Hua is also utilising the fact that ionic liquids are electrolytes to further increase their effectiveness as a lubricant.
“ILs are composed solely of cations and anions which have positive and negative charges,” Hua says.
“Lubricity can be externally controlled in situ by application of a potential to a metal surface.”
“Using this method, we can tune the structure of a boundary layer of ILs.”
Hua is correlating experimental results to computational simulations, to reveal the details of the boundary layer response, and how tribology alters with the boundary layer structure at the ionic liquid-electrode surface.
“The tunable nature of ILs enables cause/effect relationships to be teased out in ways not possible for conventional lubricants, so I am working on that.”
Not working in a vacuum
It was the potential future application of ILs that first attracted Hua to this area of study.
“In the future when we go into space, we will be working in a vacuum,” Hua says.
“Common liquids will be affected by the vacuum, but ILs are a great candidate for use in instruments and other applications in outer space.”
Hua found motivation for the other aspect of her work a bit closer to home.
“I came from China where the amount of pollutants in the air is very significant,” Hua says.
“I want to do something to contribute to fixing that, to make something better for the next generation.”
Focusing on flue gas, Hua’s immediate priority in this area is to design Ionic fluids with specific structures designed to collect or adsorb a target gas such as carbon dioxide or sulfur dioxide.
“The dream is then to design further methods to harvest the gas in pure form for reuse in other applications.”
When asked about projected time frame for such an innovation, Hua answers that support is the only variable that may delay this important innovation.
Fortunately, support does not seem to be lacking for Hua’s research.
Despite only beginning work on gas adsorption in early 2016, Hua has already secured funding from many quarters.
Hua scored a Priming Grant from The Global Connections fund, an initiative of the Australian Government aimed to promote collaboration between Australian Researchers and Small to Medium Enterprises (SMEs).
This project will see her working closely with a SME in China looking specifically at adsorption of nitric oxide (NO) from flue gas.
A grant from the National Natural Science Foundation of China will be used on a mechanism study of flue gas denitrification.
Collaborators at Deakin University as well as in several Chinese and European universities round out Team Li.
One day Hua hopes to have even more fans.
“If I can achieve something in this area, I would perhaps consider myself a hero,” she says, smiling.
But for now, it’s back to work.
Upon completing my PhD studies in Applied Science (Minerals and Materials), at Ian Wark Research Institute, University of South Australia in 2012, I was employed as a Research Associate in the Discipline of Chemistry, University of Newcastle. In January 2015 I was appointed to a full-time lecturing position in the same discipline. Currently, my research focuses on developing new and high-performance ionic liquid based lubricants, including:
- Nanostructure and Nanotribology (Nanofriction) of Ionic Liquids
As ionic liquids are composed solely of cations and anions, lubricity can be externally controlled in situ by application of a potential to an electrode surface. The ion composition in the boundary layer responds with the applied potential, and thus alters lubricity.
Experimental results will be correlated to computational simulations, so as to reveal the details of the boundary layer and how nanotribology alters with the boundary layer structure at the ionic liquid-electrode interface.
- Ionic Liquids as Lubricant Additives
Pure ionic liquids are very expensive. The high cost limits their extensive application in industry. The problem can be solved by applying ionic liquids as lubricant additives, where small amounts can markedly improve the tribological performance of commercially cheap base oils.
Tribology (friction) at both nanoscale and macroscale will be investigated so as to reveal how the ions of ionic liquids alter the lubricity at the oil-solid interfaces.
- Ionic liquids and Deep Eutectic Solvents as Atmospheric Pollutant Solvents
Anthropogenic emission of gases such as CO2, NOx and SOx of a critical challenge to the environment. Current chemical solvents for these gases use expensive, e.g. monoethanolamine which are easy to degrade, cause heavy corrosion and thus require frequent replacement. Ionic liquids and deep eutectic solvents have enormous potential in this sphere due to their designable structure and properties, higher gas solubility and specificity and enhanced stability, compared to current solvents. By exploiting these properties, this project will deliver significant economic and environmental advantages to power generation and manufacturing industries in Australia and around the world.
- Master of Engineering (Biomedical Engineering), Tianjin University - China
- Bachelor of Science / Bachelor of Arts, Tianjin University - China
- Diploma in Material Chemistry, Tianjin University - China
- Diploma in Biomedical Engineering, Tianjin University - China
Fields of Research
|030699||Physical Chemistry not elsewhere classified||30|
|039901||Environmental Chemistry (incl. Atmospheric Chemistry)||30|
|030399||Macromolecular and Materials Chemistry not elsewhere classified||40|
|Title||Organisation / Department|
|PRC Research Fellow||University of Newcastle
School of Environmental and Life Sciences
For publications that are currently unpublished or in-press, details are shown in italics.
Journal article (24 outputs)
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]
Â© 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]
Â© 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.
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]
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]
Â© 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]
Â© 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.
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]
Wang FF, Wu Y, Gao Y, Li H, Chen Z, 'Effect of humic acid, oxalate and phosphate on Fenton-like oxidation of microcystin-LR by nanoscale zero-valent iron', Separation and Purification Technology, 170 337-343 (2016) [C1]
Â© 2016 Elsevier B.V.This study investigates the effect of humic acid, oxalate and phosphate on the heterogeneous Fenton-like oxidation efficiency of microcystin-LR (MC-LR) using ... [more]
Â© 2016 Elsevier B.V.This study investigates the effect of humic acid, oxalate and phosphate on the heterogeneous Fenton-like oxidation efficiency of microcystin-LR (MC-LR) using zero-valent iron nanoparticles (nZVI) as a catalyst at neutral pH. The degradation efficiency of MC-LR in the Fenton-like system increases significantly from 59.1% to 78%, and 59.1% to 72.1% in the presence of humic acid and oxalate, respectively. These mean that humic acid and oxalate are able to form complexes with iron and iron oxide, thus promote the Fenton-like oxidation of MC-LR. However, the degradation efficiency reduces from 59.1% to 47.8% in the existence of phosphate, because phosphate adsorbs competitively with MC-LR to the nZVI surface, consequently inhibits the heterogeneous Fenton-like oxidation of MC-LR. The oxidation kinetics of MC-LR fits well with the pseudo first-order kinetic model. The results illustrate that humic acid was more effective than oxalate and phosphate to generate hydroxyl radicals. The surface changes of nZVI before and after reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR).Magnetite, maghemite, lepidocrocite and other iron complexes were detected at nZVI surfaces after reaction with MC-LR.
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]
Li H, Atkin R, Page AJ, 'Combined Friction Force Microscopy and Quantum Chemical Investigation of the Tribotronic Response at the Propylammonium NitrateÂ¿Graphite Interface', Physical Chemistry Chemical Physics, 17 16047-16052 (2015) [C1]
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]
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. Â© 2014 IOP Publishing Ltd.
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]
Â© 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]
Â© 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.
Carstens T, Gustus R, HÃ¶fft 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. Â© 2014 American Chemical Society.
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]
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]
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]
|Show 21 more journal articles|
Conference (1 outputs)
Atkin R, Li H, Sweeney J, Elbourne A, Webber G, Rutland M, Warr GG, 'Effect of surface nanostructure and ion structure on the nanotribology of the graphite: Ionic liquid interface', ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY (2014) [E3]
Grants and Funding
|Number of grants||6|
Click on a grant title below to expand the full details for that specific grant.
20172 grants / $118,000
Funding body: The University of Newcastle
|Funding body||The University of Newcastle|
|Scheme||Early Career Research HDR Candidate Scholarship|
|Type Of Funding||Internal|
Funding body: National Natural Science Foundation of China
|Funding body||National Natural Science Foundation of China|
|Scheme||National Natural Science Foundation of China|
|Type Of Funding||International - Competitive|
20163 grants / $30,800
Funding body: Univeristy of Newcastle
|Funding body||Univeristy of Newcastle|
|Scheme||Research Advantage Early Career Researcher Equipment Grant|
|Type Of Funding||Internal|
Funding body: ATSE (Australian Academy of Technological Sciences and Engineering)
|Funding body||ATSE (Australian Academy of Technological Sciences and Engineering)|
|Project Team||Doctor Hua Li|
|Type Of Funding||Other Public Sector - Commonwealth|
Removal of nitrogen oxides, such as NO2 from combustion of fossil fuels is critical due to their environmental significants. This project aims to develop deep eutectic solvents (DESs) as new, high-efficiency and low cost gas solvents for NO2 adsorption. Experimental and molecular simulation data will be combined together to identify the adsorption mechanisms of NO2 in DESs, and subsequently design DESs with the optimal chemical structure for NO2 adsorption. The project outcomes will provide fundamental knowledge for the design of new denitrifying agents and boost the development of high-performance and low-cost denitrification technologies, and thus lead to significant environmental benefits.
Funding body: Faculty of Science and Information Technology, University of Newcastle
|Funding body||Faculty of Science and Information Technology, University of Newcastle|
|Scheme||Faculty Strategic Small Grant|
|Type Of Funding||Internal|
20151 grants / $7,291
Funding body: University of Newcastle - Faculty of Science & IT
|Funding body||University of Newcastle - Faculty of Science & IT|
|Scheme||Strategic Small Grant|
|Type Of Funding||Internal|
Number of supervisions
Total current UON EFTSL
|Commenced||Level of Study||Research Title||Program||Supervisor Type|
|2016||PhD||Adsorption Processes at Perovskite Interfaces||PhD (Chemistry), Faculty of Science, The University of Newcastle||Co-Supervisor|
|2015||PhD||Polymeric Materials as Additives to Low Melting Point Salt Lubricants||PhD (Chemical Engineering), Faculty of Engineering and Built Environment, The University of Newcastle||Co-Supervisor|