Synthesis, structures, and properties of side‐chain cholesteric liquid‐crystalline polysiloxanes

Abstract

AbstractThe synthesis of three cholesteric monomers and side‐chain liquid‐crystalline polymers was described. The structure–property relationships of monomers IM–IIIM and polymers IP–IIIP were discussed. Their phase behavior and optical properties were investigated by differential scanning calorimetry, thermogravimetric analyses (TGA), and polarizing optical microscopy. Monomers IM–IIIM exhibited cholesteric oily‐streak texture and focal‐conic texture. Polymers IIP and IIIP revealed smectic A fan‐shaped texture and cholesteric grandjean texture, respectively. Experimental results demonstrated that the selective reflection of IM–IIIM shifted to the short‐wavelength region with increasing the flexible spacer length or decreasing the rigidity of the mesogen. Polymers with a longer flexible spacer had lower glass‐transition temperatures and wider mesomorphic temperature ranges. TGA showed that the temperatures at which 5% weight loss occurred were greater than 300°C for all the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3944–3950, 2003