On the abundance and general nature of the liquid–liquid phase transition in molecularsystems

Abstract

Even a single-component liquid may have more than two kinds of isotropic liquid states.The transition between these different states is called a liquid–liquid transition (LLT). AnLLT has been considered to be a rather rare phenomenon, in particular for molecularliquids. Very recently, however, we found an LLT in triphenyl phosphite, which may be thefirst experimental observation of an LLT for molecular liquids. Here we report convincingevidence of the second example of LLT for another molecular liquid, n-butanol. Despitelarge differences in the chemical structure and the molecular shape between triphenylphosphite and n-butanol, the basic features of the transformation kinetics are strikinglysimilar. This suggests that an LLT may not be a rare phenomenon restricted to specificliquids, but may exist in various molecular liquids, which have a tendency to formlong-lived locally favoured structures due to anisotropic interactions (e.g., hydrogenbonding).