Tomar Gaurav, Sharma Ashutosh, Shenoy Vijay, Biswas Gautam
Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, UP 208016, India.
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Jul;76(1 Pt 1):011607. doi: 10.1103/PhysRevE.76.011607. Epub 2007 Jul 30.
The surface of a soft elastic film becomes unstable and forms a self-organized undulating pattern because of adhesive interactions when it comes in contact proximity with a rigid surface. For a single film, the pattern length scale lambda , which is governed by the minimization of the elastic stored energy, gives lambda approximately 3h , where h is the film thickness. Based on a linear stability analysis and simulations of adhesion and debonding, we consider the contact instability of an elastic bilayer, which provides greater flexibility in the morphological control of interfacial instability. Unlike the case of a single film, the morphology of the contact instability patterns, debonding distance, and debonding force in a bilayer can be controlled in a nonlinear way by varying the thicknesses and shear moduli of the films. Interestingly, the pattern wavelength in a bilayer can be greatly increased or decreased compared to a single film when the adhesive contact is formed by the stiffer or the softer of the two films, respectively. In particular, lambda as small as 0.5h can be obtained. This indicates a new strategy for pattern miniaturization in elastic contact lithography.
当柔软的弹性薄膜与刚性表面接触接近时，由于粘附相互作用，其表面会变得不稳定并形成自组织起伏图案。对于单个薄膜，图案长度尺度λ由弹性储能的最小化决定，约为λ≈3h，其中h是薄膜厚度。基于线性稳定性分析以及粘附和脱粘的模拟，我们考虑了弹性双层的接触不稳定性，这在界面不稳定性的形态控制方面提供了更大的灵活性。与单个薄膜的情况不同，双层中接触不稳定性图案的形态、脱粘距离和脱粘力可以通过改变薄膜的厚度和剪切模量以非线性方式进行控制。有趣的是，当通过双层中较硬或较软的薄膜形成粘附接触时，双层中的图案波长与单个薄膜相比可以大大增加或减小。特别是，可以获得低至0.5h的λ。这表明了弹性接触光刻中图案小型化的一种新策略。
