V-Shaped Molecules:New Contenders for the Biaxial Nematic Phase

摘要

Since their discovery in the 1880s,the number of different thermotropic liquid-crystal phases has grown,with an increasingly complex molecular organization observed within the phases.The discovery of new phases has often been accidental,although in recent years theoretical predictions have stimulated such discoveries;the twist grain boundary phase formed on introducing molecular chirality into smectic phases is an excellent example.Another example of the prediction of a liquid-crystal phase is the biaxial nematic phase.The simplest and commercially most important liquid crystal is the uniaxial nematic phase,N_U,which is taken to have D_(propor.tob) symmetry.