Accessing New Property Combination in Soft Gel Materials with Preferential Interactions

In the past few decades, there has been a revolution in soft matter that has given us new materials with outstanding properties.¹ This talk focuses on soft gel materials prepared from highly cross-linked polymers and ionic liquids. These materials are named ionogels and their properties are very different to traditional gels such as hydrogels or organogels.² For example, ionogels are highly conductive and not susceptible to evaporation because ionic liquids are effectively involatile in atmospheric conditions. Hence, ionogels are good candidates for flexible electronics such as ionic skins, actuators, and sensors. In this talk, we show how weak preferential interactions between ionic liquid solvents and cross-linked polymers of poly(ethylene glycol) diacrylate (PEGDA) or 1,6-hexanediol diacrylate (HDDA) ionogels can be exploited to access new property combinations that would otherwise not exist. We use a range of analytical methods to pry apart the complex molecular interactions in ionogels (e.g., cation-anion, ion-polymer, polymer-polymer)³ to help understand how interactions influence structure, transport properties, and surface composition. This talk gives a comprehensive overview of ionogel properties and rationalises them in terms of molecular scale interactions, which is important for the design of emerging soft materials or gel polymer electrolytes for energy applications.