Article

Abstract

• Surfaces with tunable topological features enable important applications, such as optical devices, precision metrology, adhesion, and  wetting. In this study, we demonstrate a facile method to fabricate and control the surface morphologies by combining thin film wrinkling  and thermal expansion. This approach utilizes self-assembled surface wrinkling induced by shape recovery of shape memory polymers and  localized thermal expansion caused by Joule heating. Recovering the prestrain in the SMP substrate induces global wrinkling of the thin film  on the substrate. Joule heating in the SMP by a heating wire embedded in the substrate induces thermal expansion of the substrate in a  localized area, which leads to disappearance of the wrinkling pattern. This effect is reversed when heating is stopped, leading to reversible  and repeatable tuning of the surface morphology in a controllable localized surface region. With metal coating, the SMP surface  can be switched from specular to diffuse reflectance with respond to external Joule heating. Finally, we demonstrate a smart micromirror  device with its diffuse reflectance tunable between 13.5% to 81.9% in visible light region. This approach provides a method to modulate  surface diffusivity by controlling its surface morphologies, with potential applications in optical display and optical microelectromechanical (MEMS) devices.

Creator

• Villada, Andres
• Yin, Xiaobo
• Xiao, Jianliang
• Chen, Yizhou
• Zhai, Yao
• Zou, Zhanan
• Wang, Yu

Date Issued

• 2019-05

Academic Affiliation

• Mechanical Engineering
• Materials Science & Engineering Program

Journal Title

• Applied Physics Letters

Journal Issue/Number

• 19

Journal Volume

• 114

Last Modified

• 2020-11-13

Resource Type

• Postprint

Rights Statement

• In Copyright

Language

• English [eng]

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