Shape memory polymers (SMPs) are stimuli-responsive materials that remember their original shape that can be recovered from a temporary fixed shape by exposure to external stimuli such as heat, light, electricity, moisture, solvent, or magnetic field.
Air Force researchers have identified glassy azobenzene as one such SMP material that can bend bi-directionally when exposed to blue-green light of 440–514 nm. It retains the photo-deformed state upon removal of light for a significant period of time. It can then be returned to its original state by specific light activation. SMPs have already found commercial utility in building materials and ophthalmic devices. They will further intrude into areas like photo-responsive switches; additional medical devices such as stents, shunts, and sutures; and self-repairing vehicle structures, to name only a few potential applications.
- Fast: Short exposures generate fixity with eye-safe, linearly polarized 442 nm light (same wavelength used in photo-curable dental fillings), and all-optical shape release with right-handed circularly polarized 442 nm light
- Thermal and optical fixity: Flexibility to combine thermal and optically fixable shape memory is also included in the SMPs of this technology
- Tunable: Photo-fixed temporary shapes can be tuned by adjusting the alignment of the linear polarization to the sample
- US patent 9,475,912 available for license
- Potential for collaboration with Air Force researchers