Side-chain cholesteric liquid crystalline elastomers derived from nematic bis-olefinic crosslinking units

摘要

The synthesis of the nematic crosslinking agent (4'-allyloxy-benzoyl)-4"-undec-10-en-1-oyl-benzoyl)-p-benzenediolate (M-1), the cholesteric monomer cholesteryl undec-10-en-1-oate (M-2) and side-chain cholesteric liquid crystalline elastomers is described. The chemical structures of the obtained monomers and elastomers were confirmed by FTIR and H-1 NMR spectroscopy. Their mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction measurements. The influence of the crosslinking M-1 units on phase behavior of different elastomers prepared by a one-step hydrosilation reaction was discussed. The elastomers containing less than 20 mol-% of the crosslinking M-1 units showed elasticity, reversible phase transition and cholesteric texture. The experimental results demonstrated that the glass transition temperatures and isotropization temperatures of P-2 similar to P-6 increased with increasing the concentration of crosslinking M-1 units. [References: 30]