Hybrid Electroactive Shape Memory Polymer Composites with Room Temperature Deformability

Polymeric blend shape memory polymers (SMPs) can be constructed from two immiscible polymeric matrices. The shape recovery behavior of these composite systems can be easily controlled by varying the ratio of the polymer blends. It has been recently discovered that the functionality of SMPs can be further enhanced with electroactive ability through the use of conductive fillers. However, the fillers may negatively interact with the SMPs and cause a reduction in the elongation at failure thereby diminishing the shape recovery performance. It is proposed that a plasticizer can be utilized to alter the microstructure of the SMPs with conductive fillers. In this study, a new hybrid SMP is developed by combining single-walled carbon nanotubes (SWCNT) into a poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU) SMP system containing poly(ethylene glycol) (PEG) plasticizer. The incorporation of PEG is able to lower the activation temperature, while enhancing dispersion of SWCNT. The presence of SWCNT can stabilize the SMP system and significantly enhance the shape-fixing capability after deformation at room temperature conditions. By carefully controlling the formulation, an electroactive SMP can be created by optimizing the amount of SWCNT and PEG plasticizer.