Reconfigurable Photonic Crystals Enabled by Pressure-Responsive Shape Memory Polymers

Smart shape memory polymers can memorize and recover their permanent shape in response to an external stimulus (e.g., heat). They have been extensively exploited for a wide spectrum of applications ranging from biomedical devices to aerospace morphing structures. However, most of the existing shape memory polymers are thermoresponsive and their performance is hindered by heat-demanding programming and recovery steps. Although pressure is an easily adjustable process variable like temperature, pressureresponsive shape memory polymers are largely unexplored. Here, we report a series of shape memory polymers that enable unusual "cold" programming and instantaneous shape recovery triggered by applying a contact pressure at ambient conditions. Moreover, the interdisciplinary integration of scientific principles drawn from two disparate fields - the fast-growing photonic crystal and shape memory polymer technologies enables fabrication of reconfigurable photonic crystals, and simultaneously provides a simple and sensitive optical technique for investigating the intriguing shape memory effects at nanoscale.