Polymers with dual light-triggered functions of shape memory and healing using gold nanoparticles

Shape-memory and stimuli-healable polymers (SMP and SHP) are two types of emerging smart materials. Among the many stimuli that can be used to control SMP and SHP, light is unique because of its unparalleled remote activation and spatial control. Generally, light-triggered shape memory and optically healable polymers are different polymers and it is challenging to endow the same polymer with the two light-triggered functions because of their structural incompatibility. In this paper, we describe a general polymer design that allows a single material to exhibit both light-controlled shape memory and optical healing capabilities. We show that by chemically cross-linking a crystalline polymer and loading it with a small amount of gold nanoparticles (AuNPs), the polymer displays optically controllable shape memory and fast optical healing based on the same localized heating effect arising from the surface plasmon resonance of AuNPs. The photothermal effect controls, on the one hand, the shape memory process by tuning the temperature with respect to Tm of the crystalline phase and, on the other hand, activates the damage healing through crystal melting and recrystallization. Moreover, we show that these two features can be triggered separately in a sequential manner.