Processing of complex biopolymers, particularly proteins such as keratin and silk, has been hindered by the extremely low solubility and thus accessibility to the protein backbone of these materials. Recent work shows that room temperature ionic liquids (RTILs – liquids composed of organic-based ions) are able to overcome these issues, rendering them accessible to further processing. This opens up a wide possible range of applications for turning these materials into novel structures and composites. This proposal seeks to understand the basis of protein-ionic liquid interactions such as to make more informed decisions of which of the millions of available RTILs to use, ensuring that sustainable and environmentally compatible selections can be rationally prioritised in the future.