Mesophase Behaviors, Mesomorphic and Optical Properties of Side-Chain Liquid Crystalline Polymers Bearing Cholesteric and Nematic Mesogens

Abstract

A series of side-chain liquid crystalline polymers (LCPs) have been prepared. Their chemical structures and properties have been fully investigated. Homopolymers P₁ and P₇ show a nematic phase and a smectic A phase, respectively, and copolymers P₂-P₆ reveal a cholesteric phase. The reflection wavelengths of P₂-P₆ exhibit blue shift. P₂-P₆ display selective reflection at temperatures below the glass transition on first cooling cycle, which cannot be observed on the first heating. The isotropic phase transition temperatures and glass transition temperatures of the polymers increase with the increase of cholesteric mesogens in the polymer systems.

Keywords:

• Liquid crystalline polymers
• Mesomorphic properties
• Mesophase behaviors
• Optical properties

Notes

^a Feed molar ratio M₂/M₁+M₂ for the polymers.

^b Specific rotation of the polymers, 0.1 g in 10 mL CHCl₃ at 28°C.

^c The max selective reflection wavelengths of the polymers at 80°C.

^d Mesomorphic temperature range (ΔT = T _i − T _g).

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