(732f) Novel Pressure-Responsive Shape Memory Polymers

Shape memory polymers (SMPs) are stimuli-responsive materials that can change their shape upon application of an external stimulus (e.g., heat and light).  They have been extensively exploited for a wide spectrum of technological applications ranging from smart biomedical devices to aerospace morphing structures. Most of the currently available SMPs are thermoresponsive and they suffer from slow response speed and heat-demanding programming and recovery steps.  Although pressure is an easily adjustable process variable like temperature, pressure-responsive SMPs are largely unexplored. Here we demonstrate a new class of pressure-sensitive SMPs that enable the instantaneous recovery of the memorized shapes by applying a very small pressure. By combining these novel SMPs with self-assembled colloidal crystals, we have developed tunable macroporous photonic crystal films showing large optical stop band shifts triggered by a small pressure change. Rewritable photonic crystal microstructures, such as optical waveguides, can be easily printed on the pressure-responsive SMP films. We have also demonstrated that nanoporous smart coatings exhibiting tunable anti-glare properties can be fabricated by using the new SMPs. These pressure-responsive SMPs could find important applications in anti-counterfeiting and biometric recognition markets.