| 초록 |
Liquid crystal elastomers (LCEs) are a class of smart materials renowned for their reversible shape transformation under heat, light and solvent. In the thermotropic LCEs, the contraction parallel to the director orientation occurs when heated above nematic-isotropic temperature (Tni). 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 and rheological as well as actuation properties of the resulting 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. |
