Electroactive shape memory composites with TiO2 whiskers for switching an electrical circuit

In this paper, electrically actuated shape memory composites were prepared by compounding shape memory polyurethane (SMPU) with conductive antimony-doped tin oxide/TiO2 (ATO/TiO2) whiskers. The resultant composites, ATO/TiO2/SMPU, can be activated by electric voltages because of heating Joule and enhancement of heating efficiency by the conductive network resulting from the overlaps of whiskers. In addition to conductivity, ATO/TiO2/SMPU composites featured lighter color than most electroactive shape memory composites, which exhibit black color due to the addition of carbon materials. The composites exhibited uniform electrical resistance and rapid heat transfer performances. When the composites with 50 wt% ATO/TiO2 whiskers were used in a switch electric circuit as the switch, the circuit can turn off within 30 s. ATO/TiO2 whiskers improved Young's moduli by at least 390% and recovery stresses by more than 250% compared with pristine SMPU. Although the recovery rates were unsatisfactory in the first test cycle, composites with 40 wt'% ATO/TiO2 whiskers and 50 wt % ATO/TiO2 whiskers still showed recovery rates higher than 96% and 94% in the third cycle, respectively. (C) 2018 Elsevier Ltd. All rights reserved.