Shape Memory Effect Exhibited by Smectic-C Liquid Crystalline Elastomers

It was long expected and recently shown that main-chain liquid crystalline elastomers (MC-LCEs) may serve as high performance soft actuators due to a coupling of their intrinsic characteristics of high, yet labile, ordering and network strain. Here, we present the synthesis of new siloxane-based smectic MC-LCEs. These new materials exhibit a unique thermomechanical behavior known as the shape memory effect, which has never been observed before in such LCEs. To achieve targeted transition temperatures required for facile actuation at low temperatures, specifically temperatures ranging from 15 to 65 °C, we have designed and prepared such elastomers incorporating two distinct mesogenic groups, termed 5H and 5tB, coupled with hydride-terminated poly(dimethylsiloxane) spacers.