Molecular Engineering of Main-Chain Liquid Crystal Elastomers: The Effect of Spacer Length on the Thermal Actuation
발표자
()
초록
내용
Liquid crystal elastomers (LCEs) are smart materials renowned for the reversible shape transformation driven by change in the nematic order under heat, light and solvent. In the thermotropic LCEs, the contraction parallel to the director orientation occurs when heated above nematic-isotropic temperature (Tni). Here, we report the synthesis of a series of surface aligned LCEs prepared by aza-Michael addition between diacrylate functionalized nematic monomers and alkylamine chain extenders followed by photopolymerization. In particular, we used the spacer length of nematic monomers as a handle to manipulate thermal, mechanical as well as actuation properties of the LCEs. Specifically, both Tni and actuation temperature significantly reduce with decreasing methylene spacer from 11 to 3. Thus, molecular engineering of the LC monomers can bring a significant impact on the actuation behavior of the LCEs, which can advance in the design of programmed shape switching materials.