Synthesis and Characterization of high molecular weight side chain liquid crystalline/photoactive polymers

Abstract

Various liquid crystalline and photoactive azobenzene monomers were synthesized and attached to copoly(methyl methacrylate-glycidyl methacrylate) [copoly (MMA-GMA)] to get high molecular weight side chain liquid crystalline (LC)/photoactive copolymers. Further, spacers are generated in situ and reactive groups are obtained after the modification. All monomers and polymers were thoroughly characterized by FTIR, 1H and 13C NMR, UV-VIS spectrophotometry, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy. All side chain LC polymers showed higher thermal stability than that of copoly(MMA-GMA). Three LC and one azo monomer exhibited characteristic nematic mesophase where as one LC monomer has shown nematic and sanded smectic-A texture. The rate of trans-cis isomerization of polymer was lower than that of the monomer and both monomers and polymers showed slow back isomerization. Present approach offers convenient way to synthesize high/desired molecular weight photoactive LC polymers. © 2008 Wiley Periodicals, Inc.