Effects of Template and Molecular Nanostructure on the Performance of Organic–Inorganic Photomechanical Actuator Membranes. (13th June 2019)

• Record Type: Journal Article
• Authors: Dong, Xinning; Guo, Tianyi; Kitagawa, Daichi; Kobatake, Seiya; Palffy‐Muhoray, Peter; Bardeen, Christopher J.
• Is Part Of: Advanced functional materials. Volume 30:Number 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-13
• Subjects: composite -- molecular crystal -- nanowire -- photomechanical -- porous alumina; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201902396
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: 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. Abstract : The nanostructural properties of a photomechanical bending actuator composed of organic–inorganic hybrid materials are studied. The actuators with a lower average elastic modulus (16 GPa vs 68 GPa) generate almost an order of magnitude more photomechanical work. Both the mechanical properties of porous inorganic templates and chemical characteristics of active organic components are important to the improvement of the composite's performance.