Temperature sensing of conductive shape memory polymer composites

• A novel shape memory-based stimuli sensing strategy was presented.
• AgNW–SMPU composites exhibited strain-dependent conductivity.
• The tunable resistance could be stabilized by shape fixing.
• The composites could respond to stimuli by changing the resistance.
• The resistance reversibly changed along with shape recovery under heating.

A novel strategy of stimulus sensing is unprecedentedly presented for conductive shape memory polymer composites. Temperature stimulation makes the composites recover not only the shapes but also the conductivity as the composites experience “memorizing” process from the temporary shapes to the original shapes. Silver nanowires (AgNWs) are incorporated into the surface layer of shape memory polyurethane (SMPU). The AgNW–SMPU composites are stretchable and electrically conductive, particularly exhibiting reversible strain-dependent conductivity. The resistance increases and is subsequently stabilized at relatively higher value as the composites are extended and fixed in a typical shape memory programming. Temperature stimulation enables the composites to recover the shapes, along with large decrease in resistance. The findings disclose that the conductive shape memory composites are able to respond to external stimulus by variation of the electrical signals in a desired manner, which may greatly benefit the development of smart polymer materials in flexible electronics and sensors fields.