Synthesis and mesomorphic behavior of terminally carboxyl oligo(ethylene oxide) monomethyl ethers‐substituted side chain liquid crystalline polysiloxanes. I

A series of alkene monomers containing carboxyl biphenyl benzoate ester or carboxyl p,p′‐phenyl benzoate ester based on mesogenic core with a carboxyl (±)‐2‐methyl ethylene glycol monomethyl ether group or various lengths of carboxyl oligo (ethylene oxide) monomethyl ethers as the terminal group were synthesized. And they were grafted onto the poly(methylhydrosiloxanes) (PMHS) by the platinum catalyzed hydrosilylation process. Their molecular structure, the thermal transitions temperature, and mesophase texture of monomers and of polymers were characterized using ¹H nuclear magnetic resonance, differential scanning calorimetry, and polarizing optical microscopy with hot stage. The polymers obtained all show smectic phase while their precursor monomers show both smectic and/or nematic phase, or in some cases, no mesophase. The factors governing mesophase texture and transition temperature are discussed. © 1993 John Wiley & Sons, Inc.