Transformative Skin: Controlled Electromechanical Instability on Polymer Surfaces

这项资助的研究目的是阐明新型聚合物体系的基本机制，这些体系能够在电压控制下动态地改变其表面图案和粗糙度。这些所谓的变形性皮肤是基于PI最近发现的一种新的表面机电不稳定模式。这种不稳定性导致了丰富多样的表面图案，从随机取向的折痕和陨石坑到特征尺寸从毫米到几十纳米可调的排列线条。拟议的项目将整合一套实验、理论和计算工具，以系统地了解表面机电不稳定性。具体目标包括开发1)同时产生不稳定图案并表征其在电压下的三维地形的实验系统，2)分析不稳定图案形成的非线性场理论，以及3)耦合场模型和数值方法来模拟不稳定图案的形成和演化。如果成功，这种跨学科的合作将导致对表面机电不稳定性的首次系统了解，有可能显著扩大功能表面和电聚合物的使用。这种新型的可转化皮肤具有广泛的重要应用，包括按需超疏水、自适应光学、受控粘合、转印和防污。相反，表面机电不稳定性会在能源应用中引发各种聚合物的电气击穿和故障，包括绝缘电缆、有机电容器、聚合物致动器和发电机。目前的项目将通过利用或消除不同应用中相同的不稳定性，为明智地设计电-聚合物系统提供理论基础。研究生和本科生将接受与软材料和活性材料有关的数值方法和实验方法的培训。这笔赠款还包括一项协调努力，从科学和工程领域代表性不足的人群中招募学生，进入这一令人兴奋的新研究领域。

The research objective of this grant is to elucidate the fundamental mechanism of novel polymer systems capable of dynamically transforming their surface patterns and roughness under the control of electrical voltages. These so-called transformative skins are based on a new mode of surface electromechanical instability recently discovered by the PIs. The instability leads to a rich variety of surface patterns ranging from randomly oriented creases and craters to aligned lines with tunable feature sizes from millimeters to tens of nanometers. The proposed project will integrate a suite of experimental, theoretical, and computational tools to systematically understand the surface electromechanical instability. Specific goals include the development of 1) an experimental system to simultaneously generate instability patterns and characterize their three-dimensional topography under voltages, 2) a non-linear field theory to analyze the formation of the instability patterns, and 3) coupled-field models and numerical methods to simulate the formation and evolution of the instability patterns.If successful, this interdisciplinary collaborative effort will lead to the first systematic understanding of surface electromechanical instabilities, with the potential to significantly expand the use of functional surfaces and electrical polymers. The novel transformative skins have a broad range of important applications, including on-demand super-hydrophobicity, adaptive optics, controlled adhesion, transfer printing, and antifouling. Conversely, surface electromechanical instabilities can trigger electrical breakdowns and failures of various polymers in energy applications, including insulating cables, organic capacitors, polymer actuators, and generators. The current project will provide a theoretical foundation for judicious design of electrical-polymer systems by either harnessing or eliminating the same instability for different applications. Graduate and undergraduate students will receive training in both numerical and experimental methods related to soft and active materials. This grant further includes a coordinated effort to recruit students from underrepresented populations in science and engineering to enter into this exciting new field of research.