화학공학소재연구정보센터
Reactive & Functional Polymers, Vol.131, 44-55, 2018
Electro-optical property and stability of liquid crystal physical gels controlled by copolymerization
A series of side chain liquid crystal copolymers with different copolymerization ratios have been successfully synthesized by copolymerization of (4'-cyanobiphenyl-4-oxy) acrylate] (M0ACB, rigid component) and (4-cyanobiphenyl-4'-oxy) hexyl acrylate (M6ACB, flexible component). The liquid crystal physical gel (LC-PGel) can be prepared by blending the copolymer with 5CB. The introduction of the flexible component improves the compatibility of the copolymers and 4-pentyl-4'-cyanobiphenyl (5CB), so that the transparent gel can be obtained above the 5CB clear point. The gelation ability of the copolymer and the mechanical properties of the liquid crystalline physical gels formed by the side chain liquid crystal copolymers can be effectively regulated by changing copolymerization ratios. Further studies have found that the surface anchoring between the copolymers and 5CB also can be regulated by changing the proportion of two components in the copolymer and the composition of copolymer with the maximum surface anchoring is POACB (0.80)-co-P6ACB (0.20). The copolymerization ratios can further regulate the electro-optical properties of the LC-PGel .by changing the surface anchoring. The stronger surface anchoring can lead to higher driving voltage and contrast ratio of LC-PGel. However, after orientation in an electric field, the increased surface anchoring can help the LC-PGel recover faster to its original state.