Electrical and thermal stimuli responsive thermoplastic shape memory polymer composites containing rGO, Fe3O4 and rGO–Fe3O4 fillers.

This work addresses a facile and broadly applicable method of fabricating a new thermoplastic shape memory polymer (SMP) composite by blending three biopolymers such as polyvinyl alcohol, polyvinyl pyrrolidone and polyethylene glycol. Reduced Graphene (rGO) is used as electrical conductive fillers. Iron Oxide (Fe3O4) and rGO-Fe3O4 combination provides thermo-electric stimulus. Under the thermal stimulus, shape recovery rate of the SMP with hybrid fillers was faster, having quick response time (28 s) compared to electrical stimulus response time (75 s). The conductivity of the SMP matrices increased by 7, 10 and 15 orders of magnitude by incorporating Fe3O4, rGO and rGO- Fe3O4 fillers, respectively. Moreover, the proposed shape memory polymer containing rGO-Fe3O4 filler exhibits a higher Young’s modulus (>80%) compared to neat polymer (1.75 GPa at room temperature and 0.6 GPa at glass transition temperature, Tg). A maximum stress of 2.5 MPa and 4% recoverable strain was achieved in the SMP with 10 and 15 wt% of hybrid fillers and interestingly no stored strain evolves, upon cooling below Tg. The developed SMP may be applied in morphing wing and other smart actuator applications