New LMM Organosiloxanes with Photoisomerising AZO Groups

Abstract

A new LMM photo-reactive chiral azo-containing organosiloxane (C₁₀Azo*B) and its racemic analogue (C₁₀Azo±B) have been synthesised and their mesomorphic properties investigated. The materials are denoted C₁₀Azo*B and C₁₀Azo(±)B where C_n refers to the number of methylene units in the alkyl spacer, Azo* and Azo(±) denote the chiral and racemic photoisomerising azobenzene-based mesogenic moiety and B refers to the pentamethyldisiloxane tail. Both LMM siloxane derivatives exhibit a single enantiotropic smectic A phase. Results on the consequences of incorporating these new materials into a related fast switching, LMM ferroelectric organosiloxane host will be given. In addition results will be presented on the photoisomerisation of the azo materials and their use in optically manipulating the magnitude of spontaneous polarisation in a ferroelectric liquid crystal.