Mechano-Chemical Coupling in the Adhesion of Thin Shell Structures: Transitions Between Weakly- and Well- Bonded States

薄壳结构黏附中的机械-化学耦合：弱键态和良好键态之间的转变(CMMI ？[0900058] PI: John L. bassan，宾夕法尼亚大学机械工程与应用力学系，PA 1994薄膜的键合和生物细胞的粘附是具有某些共同的机械、化学和热力学特性的重要课题，这些特性激发了提出的研究。总体目标是了解薄膜或外壳与衬底之间的粘附状态是如何由内在的物理和化学性质控制的。对于非协调体，这些状态受到运动相容、力平衡和化学平衡的约束。分子信息，例如，应力对键动力学的影响，将被纳入宏观模型。弱粘附状态和强粘附状态之间的转换，在提案中被称为“吸进/吸出”现象，具有广泛的含义。在各种耗散机制（包括扩散和应力对键合的影响）的影响下，对snap-in和snap-out粘合剂过渡的控制，在微电子机械系统（MEMS）、医疗甚至数据存储等应用中提供了潜力。由于制造缺陷或潮湿导致的晶圆快速脱粘是MEMS技术的一个问题。快速转变也可能是存在于白细胞自然循环中的附着-分离机制的关键。另一个令人兴奋的应用是组织工程，细胞可以通过附着在有图案的基质上排列。另一个例子是：已经有许多癌症治疗的临床试验试图打破肿瘤细胞的粘附，也许对粘附的机械化学的更好理解可以为其他治疗进步指明道路。

Mechano-chemical Coupling in the Adhesion of Thin Shell Structures:Transitions between Weakly- and Well- Bonded States (CMMI ? 0900058)PI: John L. BassaniDepartment of Mechanical Engineering and Applied MechanicsUniversity of Pennsylvania, PA 19104Bonding of thin films and adhesion of biological cells are important topics with certain common mechanical, chemical, and thermodynamic characteristics that motivate the proposed research. The overall objective is to understand how the adhered state between a thin film or shell and a substrate is controlled by intrinsic physical and chemical properties. For non-conforming bodies, these states are constrained by kinematical compatibility, force equilibrium, and chemical equilibrium. Molecular information, for example, the effects of stress on the kinetics of the bond, will be incorporated into macroscopic models. Transitions between weakly and strongly adhered states, what are referred to in the proposal as a snap-in/snap-out phenomena, have broad implications. The control of snap-in and snap-out adhesive transitions, with and without the influence of various dissipative mechanisms including the effects of diffusion and of stress on bonding, offer potential in applications ranging from micro-electro-mecahnical systems (MEMS), medical treatments, and even data storage. Snap debonding of wafers due to fabrication defects or due to moisture is a problem for MEMS technologies. Snap transitions also may be key to the attachment-detachment mechanism that are present in the natural cycles of white blood cells. Another exciting application is tissue engineering in which cells can be aligned by adhering to patterned substrates. One additional example: there have been many clinical trials for cancer treatment that attempt to breakdown the adhesion of tumor cells, and perhaps a better understanding of the mechano-chemistry of adhesion can point the way to other therapeutic advances.