Mechanics of Miniature Surface Craters for Reversible Adhesion

该奖项支持陨石坑表面力学的基础研究。可逆粘合剂被设计成形成临时粘合，并且理想地可以是可重复使用的并且能够牢固粘合。这种可逆粘合剂可以广泛应用于垂直安装和攀爬、可释放晶片和芯片处理以及可重复使用的生物集成电子器件。众所周知，可逆粘附可通过表面相互作用如货车德瓦尔斯（vdW）、毛细管力和静电力以及体积效应如吸力来实现。由于表面相互作用的粘附已经被很好地研究了壁虎启发的微纤维具有不同的尖端形状，包括凹形。但在微尺度下，吸力的贡献被普遍忽略。然而，制造具有大纵横比的微纤丝可能是昂贵且耗时的。如果一系列中尺度的陨石坑可以提供高的粘合强度和可逆性，它们可能成为微纤维的实际替代品。这项研究的结果将指导坑状表面的设计和优化，并在广泛的尺度范围内对吸力效应的争论给出明确的答案。它还将为开发用于工程和医学领域各种应用的新型上级粘合剂开辟一条道路。在以往教育和外联活动良好记录的基础上，通过NASCENT REU和妇女工程项目（WEP），PI将继续为少数民族学院的本科生和高中生提供专门设计的研究机会这项研究的研究目标是测试聚合物表面上的微型陨石坑阵列可以显著改善聚合物表面的可逆性的假设。具有压敏强度的粘合力。本研究的前提是，可以针对不同的应用程序，通过选择适当的几何和机械性能，以及预加载程序的弹坑表面。这种剪裁的核心是对粘附和脱粘机制的基本多尺度理解。该研究小组计划通过以下三个研究方向，在广泛的尺度范围内对有坑聚合物表面的可逆粘附力进行基本了解：（i）制造尺寸从厘米到微米的表面坑。(ii)牵引-分离关系和拉脱力的测量。(iii)建模与仿真。该项目将由一个协同团队进行，该团队在微细加工，粘附力学，建模和仿真方面具有互补的专业知识。

This award supports fundamental research on the mechanics of cratered surfaces. Reversible adhesives are designed to form temporary bonds, and ideally can be reusable and capable of strong bonding. Such reversible adhesives can find wide applications in vertical mounting and climbing, releasable wafer and chip handling, as well as reusable bio-integrated electronics. It is well known that reversible adhesion can be achieved through surface interactions such as van der Waals (vdW), capillary, and electrostatic forces as well as volume effects such as suction. Adhesion due to surface interactions has been well studied for gecko-inspired microfibrils with different tip shapes including the concave shape. But the contribution from suction has been widely neglected at microscale. However, manufacturing microfibrils with large aspect ratio can be expensive and time-consuming. If an array of meso-scale craters could provide combined high adhesive strength and reversibility, they may become a practical substitute for microfibrils. The results of this research will guide the design and optimization of cratered surfaces and give a definitive answer to the debate of the suction effect across a broad range of scales. It will also create a pathway for developing a new class of superior adhesives for various applications in engineering and medicine. Building upon the strong track record of previous educational and outreach activities, the PIs will continue to provide research opportunities specifically designed for undergraduate and high-school students from minority institutes through NASCENT REU and women in engineering programs (WEP) at UT Austin.The research objective of this research is to test the hypothesis that arrays of miniature craters on polymer surfaces can lead to significantly improved reversible adhesion with pressure-sensitive strengths. The premise of this research is that cratered surfaces can be tailored for various applications, by choosing proper geometric and mechanical properties, as well as the preloading program. Central to this tailoring is a fundamental multi-scale understanding of the adhesion and decohesion mechanisms. The research team plans to develop a fundamental understanding of reversible adhesion of cratered polymeric surfaces in a broad range of scales through the following three research thrusts: (i) Fabrication of surface craters with sizes ranging from centimeters to micrometers. (ii) Measurements of traction-separation relations and pull-off forces. (iii) Modeling and simulation. The project will be carried out by a synergetic team with complementary expertise in microfabrication, adhesion mechanics, modeling, and simulation.