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Effects of Template and Molecular Nanostructure on the Performance of Organic–Inorganic Photomechanical Actuator Membranes
Author(s) -
Dong Xinning,
Guo Tianyi,
Kitagawa Daichi,
Kobatake Seiya,
PalffyMuhoray Peter,
Bardeen Christopher J.
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201902396
Subject(s) - materials science , photochromism , template , diarylethene , photoisomerization , nanostructure , membrane , composite material , elastic modulus , nanotechnology , chemical engineering , isomerization , catalysis , organic chemistry , chemistry , biology , engineering , genetics
Porous anodic aluminum oxide (AAO) membranes template the growth of photochromic crystalline nanowires. The resulting organic–inorganic composite can function as a photomechanical bending actuator. 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. There is a significant variation in both morphology and elastic modulus for two commercially available AAO templates with nominally identical pore diameters of 200 nm. After these templates are filled with diarylethene molecules that undergo a ring‐open to ring‐closed photoisomerization, the light‐generated curvature and mechanical work are evaluated using two different methods. The templates with a lower average elastic modulus (16 GPa vs 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.