(37f) Broadband Light-Responsive Smart Nanocomposites Enabled By Graphene Oxide-Reinforced Shape Memory Polymers
Light-responsive shape memory polymers (SMPs) have previously been developed by exploring cyclic photofixing and photocleaving of covalently grafted chromophores induced by long (~ 60 min) ultraviolet light illumination. This slow response speed greatly impedes practical applications of these smart polymeric materials. Here we report a new type of multifunctional nanocomposites that enable instantaneous response to broadband laser illumination. Graphene oxide nanoplatelets are blended with a variety of multi-stimuli-responsive shape memory polymers, which exhibit unconventional all-room-temperature shape memory effects. Macroporous graphene oxide-SMP photonic crystal membranes are then fabricated by a templating approach using self-assembled colloidal crystals as structural templates. The periodic macropores are deformed by an evaporation-induced âcoldâ programming process. Laser illumination can trigger rapid recovery (in seconds) of the memorized 3-D ordered photonic crystal structure of the deformed macropores, leading to strong Bragg diffraction of the incident laser. The basic shape memory mechanisms of these light-responsive nanocomposites have been systematically investigated by mechanical and thermomechanical techniques (e.g., nanoindentation, optical reflection measurements, TGA and DMA tests). This new type of smart nanocomposites could find important applications as protective layers for countering high-energy laser weapons.