Light-Controlled Complex Deformation and Motion of Shape-Memory Polymers Using a Temperature Gradient.

A unique property of photothermal effect-based shape-memory polymers (SMPs) is demonstrated using a chemically cross-linked poly(ethylene oxide) (PEO) loaded with a small amount (0.5 wt %) of gold nanoparticles (AuNPs). We show that controlled surface plasmon resonance absorption of AuNPs allows for the formation of a temperature gradient in the polymer of temporary shape, which results in anisotropic polymer chain relaxation and strain energy release. This photoinduced temperature gradient effect enables the use of a laser to create a multitude of deformations and to control sophisticated motion executing mechanical work that are otherwise inaccessible with SMPs.