Organogel formation rationalized by Hansen solubility parameters: influence of gelator structure

Abstract

Some organic compounds form gels in liquids by forming a network of anisotropic fibres. Based on extensive solubility tests of four gelators of similar structures, and on Hansen solubility parameter formalism, we have probed the quantitative effect of a structural variation of the gelator structure on its gel formation ability. Increasing the length of an alkyl group of the gelator obviously reduces its polarity, which leads to a gradual shift of its solubility sphere towards lower δ_p and δ_h values. At the same time, its gelation sphere is shifted – to a much stronger extent – towards larger δ_p and δ_h values.