ABSTRACT
We observed the spontaneous shape change of a uniaxially oriented liquid–crystalline elastomer composed of smectic main-chain liquid–crystalline polyesters in a cyclic heating–cooling process. Although the elastomer contracted by about 650% on heating up to the isotropic phase, the sample length recovered by about 450% on cooling to room temperature in the first heating–cooling process. In contrast, the elastomer exhibited completely reversible deformation in the second heating–cooling process. The shape change occurred with almost no change in the orientational order of mesogens in the temperature region of the liquid–crystalline phase. The mechanism of the spontaneous thermotropic shape change is discussed.
GRAPHICAL ABSTRACT
Disclosure statement
No potential conflict of interest was reported by the authors.