Entropy driven polymorphism in liquids and mesophases consisting of three block amphiphilic molecules

Abstract

The phase behavior and the structure of athermal systems consisting of amphiphilic three-block molecules are studied using Monte Carlo molecular simulations. A coarse grain molecular prototype is introduced that mimics the very basic features of real bola and facial T- and V-shaped amphiphilic liquid crystals. Entropy driven phase polymorphism of liquids and liquid crystals is obtained by varying the size and/or the shape of the lateral block of the molecules. Such polymorphism includes non-conventional smectics, columnars and hierarchical lamellar phases. The results indicate that the isotropic liquids possess different local order; the geometry of the most probable local molecular order (molecular domain) in the liquid offers a natural explanation for the type of the observed mesophase(s). These findings provide a coherent bottom up interpretation of the diversity of the phases exhibited by amphiphilic liquid crystals.