Tunable shape-memory behaviors in amorphous polymers through bound solvent

Abstract

Shape-memory polymers (SMP) have been widely applied in biomedical areas as vascular stents, occlusion devices, fracture fixators, etc. The shape recovery region is the key factor for the performance of the SMP-based devices. In this paper, we describe a feasible method to tune the shape-recovery region of amorphous polymers. A lightly crosslinked acrylate polymer is synthesized and treated by isopropyl alcohol for a different amount of time. The dynamic mechanical analysis shows that the glass transition region is lowered by 25–75°C through varying the immersion time in isopropyl alcohol. The dry and wet polymers all show excellent thermally-induced shape-memory behaviors, while the shape-recovery region can be adjusted as much as 70°C. The method is universal, which can be applied to other polymer-solvent systems to achieve tunable shape-memory behaviors.