Shape Matters: A Gold Nanoparticle Enabled Shape Memory Polymer Triggered by Laser Irradiation

With incorporation of gold nanoparticles, i.e., nanorods (AuNR) and nanospheres (AuNS), into a polyurethane-based shape-memory polymer (SMP) EG-72D matrix, SMP nanocomposite films capable of being remotely triggered by low-power laser are fabricated and characterized using UV-vis-NIR spectroscopy, X-ray scattering, and dynamic mechanical analysis (DMA). It is demonstrated that, with incorporation of very low concentration of gold nanorods (approximate to 0.1 wt%), the mechanically programmed EG-72D/AuNR nanocomposite presents rapid response to low power laser irradiation (785 nm, approximate to 10 mW). Comparative studies on the laser irradiation response of EG-72D/AuNS and EG-72D/AuNR nanocomposite films suggest that AuNRs have significantly higher photothermal conversion efficiency than AuNS and on-resonance laser irradiation, matching the wavelength of the incident laser with the longitudinal plasmon resonance of AuNR, is necessary to induce the fast response of gold nanoparticle enabled SMP nanocomposites.