Moisture‐Responsive Wrinkling Surfaces with Tunable Dynamics |
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Authors: | Songshan Zeng Rui Li Stephan G Freire Vivian M M Garbellotto Emily Y Huang Andrew T Smith Cong Hu William R T Tait Zichao Bian Guoan Zheng Dianyun Zhang Luyi Sun |
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Affiliation: | 1. Department of Chemical and Biomolecular Engineering and Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT, USA;2. Department of Mechanical Engineering, University of Connecticut, Storrs, CT, USA;3. Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA |
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Abstract: | The wrinkle dynamics (such as reversibility and stability) of human skin are affected by the external stimuli, as well as the skin's structure and mechanical properties. Inspired by these tunable responses, three types of moisture‐responsive wrinkle dynamics are achieved, for the first time, through a single film–substrate system. These dynamics include: (1) completely reversible wrinkles formation; (2) irreversible wrinkles formation I: the initially formed wrinkles can be permanently erased and never reappear; and (3) irreversible wrinkles formation II: once the wrinkles form, they can no longer be erased. The key to success is to control the stiffness and thickness ratios of the film and the substrate, and tailor the crosslink degree/gradient of the film to allow for moisture‐dependent changes of modulus and swelling degree. These unique responsive dynamics motivate the invention of a series of optical devices triggered by moisture, including anticounterfeit tabs, encryption devices, water indicators, light diffusors, and antiglare films. This study also paves the road for further understanding of the skin wrinkling dynamics and manipulation. |
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Keywords: | moisture‐responsive dynamics polydimethylsiloxane polyvinyl alcohol soft matter |
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