MWCNTs filled PCL covalent adaptable networks: Towards reprocessable, self-healing and fast electrically-triggered shape-memory composites

Abstract

Electrically triggered shape memory polymers efficiency has been proven by numerous studies making them promising novel structural materials for high-end applications. In this field, poly(ε-caprolactone) covalent adaptable networks (PCL-CAN) are particularly appealing since they benefit from excellent shape memory (SM) properties combined with network reconfiguration making easy the design of self-actuated devices of complex shape. Preparation of conducting PCL-CAN networks by melt blending multi-walled carbon nanotubes (MWCNTs) with four-arm star-shaped PCL end-capped with maleimide and furan groups is here investigated. The conventional tensile tester and dynamic mechanical analysis demonstrated the reinforcement of the composite mechanical properties paired with excellent shape memory properties (recovery and fixity ratios about 99%). The simultaneous measurement of the sample resistivity was also integrated to these experiments allowing to follow its evolution during the SM cycles. Rheological measurements highlighted the impact of MWCNTs on the recyclability and self-healing properties of the composite. Electrical triggering of the shape recovery through Joule resistive heating is also deeply studied. The combination of all these properties in the developed material offers unique opportunities to design self-folding multi-materials which is illustrated through the design of smart multi-layered composites. This high-performance composite is especially attractive for reconfiguration of the permanent shape of complex geometry self-deploying devices and their thermal and electrical triggering.