Institute of Industrial Science, The University of Tokyo , 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
Department of Mechanical and Aerospace Engineering, University of California, Los Angeles , Los Angeles, California 90095, United States.
ACS Appl Mater Interfaces. 2016 Sep 14;8(36):24230-7. doi: 10.1021/acsami.6b07957. Epub 2016 Aug 31.
Wrinkles on thin film/elastomer bilayer systems provide functional surfaces. The aspect ratio of these wrinkles is critical to their functionality. Much effort has been dedicated to creating high-aspect-ratio structures on the surface of bilayer systems. A highly prestretched elastomer attached to a thin film has recently been shown to form a high-aspect-ratio structure, called a ridge structure, due to a large strain induced in the elastomer. However, the prestretch requirements of the elastomer during thin film attachment are not compatible with conventional thin film deposition methods, such as spin coating, dip coating, and chemical vapor deposition (CVD). Thus, the fabrication method is complex, and ridge structure formation is limited to planar surfaces. This paper presents a new and simple method for constructing ridge structures on a nonplanar surface using a plastic thin film/elastomer bilayer system. A plastic thin film is attached to a stress-free elastomer, and the resulting bilayer system is highly stretched one- or two-dimensionally. Upon the release of the stretch load, the deformation of the elastomer is reversible, while the plastically deformed thin film stays elongated. The combination of the length mismatch and the large strain induced in the elastomer generates ridge structures. The morphology of the plastic thin film/elastomer bilayer system is experimentally studied by varying the physical parameters, and the functionality and the applicability to a nonplanar surface are demonstrated. Finally, we simulate the effect of plasticity on morphology. This study presents a new technique for generating microscale high-aspect-ratio structures and its potential for functional surfaces.
薄膜/弹性体双层系统上的皱纹提供了功能性表面。这些皱纹的纵横比对于它们的功能至关重要。人们已经付出了很大的努力来在双层系统的表面上创建高纵横比的结构。最近,人们发现,将高度拉伸的弹性体附着到薄膜上,由于弹性体中产生的大应变,会形成一种高纵横比的结构,称为脊结构。然而,在薄膜附着过程中弹性体的预拉伸要求与传统的薄膜沉积方法(如旋涂、浸涂和化学气相沉积(CVD))不兼容。因此,制造方法复杂,脊结构的形成仅限于平面表面。本文提出了一种新的简单方法,用于使用塑料薄膜/弹性体双层系统在非平面表面上构建脊结构。将塑料薄膜附着到无应力的弹性体上,然后对所得的双层系统进行一维或二维的高度拉伸。在释放拉伸载荷时,弹性体的变形是可逆的,而塑性变形的薄膜保持伸长。弹性体中产生的长度不匹配和大应变的组合会产生脊结构。通过改变物理参数来实验研究塑料薄膜/弹性体双层系统的形态,并展示其功能和在非平面表面上的适用性。最后,我们模拟了塑性对形态的影响。本研究提出了一种新的用于生成微尺度高纵横比结构的技术及其在功能表面上的潜在应用。