Deep eutectic solvents (DES) are mixtures of organic salts and hydrogen bond donors, that form strongly hydrogen-bonded room temperature liquids. DES share many features with ionic liquids (ie. tunable physicochemical properties) which makes them viable green solvents that are less toxic than typical ILs. Recently a series of "hydrophobic" DES have been reported which do not mix with water, and are composed of menthol with long chain fatty acids. We have demonstrated that these solvents have internal nanoscale structure, and preferentially solubilise hydrophobic species. We wish to determine if these species swell the hydrophobic region of the solvent, and thus whether these solvents can be used to sequester species such as styrene, to alter reactivity ratios in co-polymerisations or to alter the micellisation of surfactants to control synthesis of mesoporous inorganic materials.