Shape memory behavior of liquid-crystalline elastomer/graphene oxide nanocomposites

Liquid-crystalline elastomer (LCE) nanocomposites exhibiting shape memory properties were prepared by dispersing a chemically modified graphene oxide (GO) in a smectic, lightly crosslinked epoxy resin obtained by curing p-bis(2,3-epoxypropoxy)-?-methylstilbene (DOMS) with sebacic acid (SA). Chemical grafting of DOMS monomer on GO particle surface improved interfacial adhesion between the epoxy matrix and the filler. The obtained nanocomposite films were characterized in their phase behavior, morphological and thermal properties. Furthermore, their shape memory properties were analyzed through two-way thermomechanical cycling tests. The combination of the LCE liquid crystallinity and the efficient dispersion of functionalized GO resulted in toughened, highly oriented systems endowed with enhanced shape memory response. Incorporation of 0.15 wt.% GO resulted in a significant increase of spontaneous elongation and reduced actuation temperature during cycling thermomechanical tensile testing, demonstrating the potential of these systems as shape memory materials for sensors and actuators.