Photoresponsive triple shape memory polymers with a self-healing function based on poly (lactic acid)/polycaprolactone blends

Abstract

Self-healing shape memory polymers (SMPs) have considerablepotential in advanced manufacturing and biomedical fields. Polypyrrole (PPy) exhibits excellent photoconversion properties, which may be utilized in SMP formulation; however, its application in this regard has not been explored. In this study, PPy-filled polymer nanocomposites were prepared to investigate their shape memory and self-healing characteristics. First, poly(lactic acid) (PLA) and polycaprolactone (PCL) were blendedto form PLA/PCL shape memory matrices. An 80:20 PLA/PCL blend showed excellent triple-shape memory performance with shape recovery rates (Rr1, Rr2, and Rr3Rr) of 92%, 87%, and 93%, respectively PPy nanoparticles were then incorporated into the blend as photothermal conversion fillers to develop photoresponsive SMPs. SMPs. The resulting PLA/PCL/PPy nanocomposites exhibited elevated surface temperatures during near-infrared (NIR) irradiation, thus demonstrating the photoconversion effect. In addition, these nanocomposites showed reversible triple-shape change behavior and excellent self-healing efficiencies upon NIR exposure, owing to the controllable melting and recrystallization of the PLA and PCL phases. Furthermore, the material properties of severed nanocomposites were restored after self-healing. These results, in addition to the biocompatibility and simple fabrication process of these materials, therefore demonstrate the potential utility of PPy-filled SMPs in several applications, including soft robotics and biomedical devices.