Liquid Crystal Elastomers

Abstract

Liquid crystal elastomers (LCEs) are cross-linked networks of polymeric chains containing liquid crystal mesogens. The molecular order in a solid crystal, a liquid crystal, and a liquid is compared schematically in Fig. 6.1. Computer simulations of a nematic (From the Ancient Greek νη̂ μα (néma, thread). The word nematic was coined by G. Friedel (Annales de Physique 9(18):272–474, 1922) (see also de Gennes and Prost (The Physics of Liquid Crystals, 2nd ed, Clarendon Press, Oxford, 1993)).) LCE are illustrated in Fig. 6.2. Fig. 6.1Fig. 6.2Molecular dynamics simulation of structure and physical responses in a thermotropic nematic elastomer: the material sample extends on cooling as the liquid crystal mesogens align in the nematic phase at low temperature, with the orientation of nematic director n shown, and contracts on heating as the mesogens are unaligned in the isotropic phase at high temperatures [370]