We develop fundamental insights into how intermolecular forces drive molecular assembly into complex, functional, nanostructured liquid, gel, and solid materials, and use these to control properties and improve performance for a range of applications.
Water is the essential solvent for life and all biological processes we know of, driving lipid bilayer formation and protein folding through hydration and the hydrophobic effect. These factors are also critical in many formulations from pharmaceutical and personal care formulations to foods to industrial products, which have all evolved or been developed to operate under ambient conditions. Conventional wisdom states that the hydrogen-bond network of water is key to the hydrophobic effect. We seek to better understand water’s behaviour by replacing it with newly-developed alternatives that mimic some or all of its interactions and properties, but which are stable over much wider temperature and pressure ranges.
These new solvents include Ionic Liquids (salts that melt below or near room temperature); Deep Eutectics (mixtures of solids whose interactions between components stabilize the liquid); Water-in-Salt Electrolytes (highly concentrated salts that remain liquid at room temperature).
Engineering molecular assembly requires balancing forces between the solvent and the polar and non-polar parts of bilayer-forming amphiphilic compound like lipids and surfactants. This balance changes when water is replaced with other polar solvents, affecting bilayer stability.
In this project we are designing amphiphilic ionic liquids that form bilayers in water and combining them with other new solvents to create lubricant formulations that will not evaporate for aerospace and high-temperature applications.
In this project we explore how terrestrial lipids assemble when water is replaced with another solvent. This gives insights into cryopreservation of biological materials and helps us understand whether water is truly an essential component for biogenesis.
Water’s hydrogen-bond network cannot be maintained at low concentrations, yet amphiphiles still self-assemble in such low-water environments. We are exploring the roles of other interactions in such environments.
In this project we are examining amphiphile self-assembly in solvents where all the water is coordinated to metal salts. Modulating the coordination affects the way polar groups are hydrated, leading to new structures with new properties.
Surfactants are commonly added to electrolytes to stabilise electrode surfaces, which also gives rise to micelle formation. In this project we are exploring how very low water content affects surfactant self-assembly.
Inspired by organisms that can survive and recover from drought and dehydration, we are exploring how new solvents can be used to create hyperconcentrated “just add water” formulations. These products will reduce the environmental and economic impacts of transport to remote communities and locations.
Many ionic liquid-based solvents show great potential as safe, next-generation electrolytes for devices, but a significant impediment to their uptake is their high viscosity. We are investigating how to reduce viscosity by dilution with environmentally benign solvents without impacting their many positive features.
Many successful LCE diluents are fluorinated compounds, which are persistent pollutants in the environment. In this project we are designing non-fluorinated, environmentally benign alternatives by controlling interactions with the parent ionic liquid.
Current battery technologies rely heavily on lithium ion technology. In this project we examine how LCEs can be developed with sodium, magnesium and other ions for next-generation electrical devices.
The Warr Group is led by Professor Greg Warr. For enquiries, please get in contact at gregory.warr@sydney.edu.au.
