Photomechanical nanocrystals themselves are organized on macroscopic length scales using a porous inorganic template. The resulting organic-inorganic composite can function as a photomechanical bending actuator. This hybrid organic–inorganic photomechanical material acts as a bending actuator. Using ultraviolet and visible photons as power inputs, as little as 0.1 mg of reacted material generates enough force to tilt a 1.28 g mirror and steer a laser beam. The motion can be cycled multiple times in air and under water. Actuator figures-of-merit such as energy-to-work conversion efficiency and stiffness are probably limited by the high elastic modulus of the inorganic template, providing an obvious pathway for optimization.<br/>In order to investigate how the nanostructural properties of both the organic and inorganic components affect the photomechanical response, the composite mechanical properties are characterized using a variety of methods. The templates with a lower average elastic modulus (16 GPa versus 68 GPa) generate almost an order of magnitude more photomechanical work. The dependence of the photomechanical response on the chemical structure of the photochrome is assessed by comparing the performance of a diarylethene that undergoes a crystal expansion to that of one that undergoes a contraction, which leads to a decrease in curvature. Both the inorganic template and the organic active component play important roles in the overall photomechanical response, with substantial room to improve the performance.

Effects of template and molecular nanostructure on the performance of organic-inorganic photomechanical actuator membranes based on aligned nanocrystals

2019 Fall National Meeting

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