Ouchi Tetsu, Hayward Ryan C
Department of Polymer Science and Engineering , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States.
ACS Appl Mater Interfaces. 2020 Feb 26;12(8):10031-10038. doi: 10.1021/acsami.9b22662. Epub 2020 Feb 14.
Surface deformation modes, such as wrinkling, creasing, and cracking, enable a plethora of surface morphologies under mechanical loading, which have been widely exploited to provide flexibility and stretchability to electronic devices. As each phenomenon offers a distinct set of potential advantages, controlling the types and spatial locations of deformation modes is key for their successful application. In this study, we demonstrate a method to simultaneously harness multiple surface deformation modes-wrinkles, creases, and cracks-in patterned multilayer films. The wrinkling of metal-coated stiff patterned films provides flexibility and stretchability, while the reversible formation of creases in the intervening regions of the bare elastomer is used to template the formation of patterned cracks in the metal. While conventional cracks can be difficult to precisely control, the patterned cracks demonstrated here remain straight over long distances and show tunable lateral spacings from hundreds of micrometers to centimeters. Finally, the reversible opening and closing of these cracks under mechanical loading provides mechanically gated electrical switches with small and tunable critical switching strains of 0.05-0.18 and high on/off ratios of >10, enabling the preparation of mechanical NAND and NOR logic gates each composed of multiple patterned switches on a single elastomer surface.
诸如起皱、折痕和开裂等表面变形模式，能在机械载荷作用下产生大量的表面形态，这些形态已被广泛用于赋予电子设备柔韧性和拉伸性。由于每种现象都具有一系列独特的潜在优势，控制变形模式的类型和空间位置是其成功应用的关键。在本研究中，我们展示了一种在图案化多层膜中同时利用多种表面变形模式——皱纹、折痕和裂纹——的方法。金属涂层刚性图案化薄膜的起皱提供了柔韧性和拉伸性，而在裸弹性体中间区域可逆形成的折痕则用于在金属中模板化图案化裂纹的形成。虽然传统裂纹可能难以精确控制，但此处展示的图案化裂纹在很长距离内保持笔直，并显示出从数百微米到厘米的可调横向间距。最后，这些裂纹在机械载荷下的可逆开合提供了机械门控电开关，其具有0.05 - 0.18的小且可调的临界开关应变以及>10的高开关比，能够在单个弹性体表面制备由多个图案化开关组成的机械与非门和或非门逻辑门。
