Selective localization of multi-walled carbon nanotubes in bi-component biodegradable polyester blend for rapid electroactive shape memory performance

In this study, we reported a rapid electroactive ternary shape memory polymer (SMP) composites containing multiwalled carbon nanotubes (MWCNTs) and two biodegradable polyesters, namely poly(propylene carbonate) (PPC) and poly(lactic acid) (PLA). To do this, binary polymer blends were firstly prepared, and a good shape memory behavior was observed for blends with co-continuous phase morphology, where by PPC acted as the switching domain due to its good elasticity and PLA acted as the fixing domain due to its high modulus. Then MWCNTs were incorporated into PPC/PLA co-continuous phase (PPC70/PLA30, PPC50/PLA50) by simple melting blending to realize the electroactive shape memory properties. It was found that MWCNTs tended to locate more in the PPC phase than in the PLA phase. The selective localization of MWCNTs not only led to an improvement in the recovery force, but also imparted composites with high electrical conductivity in a low percolation threshold. The composites showed rapid electroactive shape memory behavior, which reached a shape recovery ratio of 97% within 30 s at 30 V. Our work provides a simple approach to utilize the selective localization of MWCNTs in the continuous phase to fabricate rapid electrical actuated SMPs with low MWCNTs loadings, which can be scaled up industrially.