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

薄壳结构粘合中的机械力-化学耦合：弱结合状态和良好结合状态之间的转变(Cmmi？0900058)PI：John L.Bassani宾夕法尼亚大学机械工程和应用机械系，宾夕法尼亚大学19104薄膜的结合和生物细胞的粘合是具有某些共同的机械、化学和热力学特征的重要课题，它们推动了拟议的研究。总体目标是了解薄膜或外壳与衬底之间的附着状态是如何由固有的物理和化学特性控制的。对于非协调体，这些状态受运动学兼容性、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。弱结合态和强结合态之间的转变，在提案中被称为卡合/卡出现象，具有广泛的含义。卡扣式和卡扣式胶粘剂过渡的控制具有或不受各种耗散机制的影响，包括扩散和应力对粘接的影响，在从微电子机械系统(MEMS)、医疗甚至数据存储的应用中提供了潜力。由于制造缺陷或潮湿导致的晶片快速脱粘是MEMS技术面临的一个问题。Snap转变也可能是白细胞自然周期中附着-脱离机制的关键。另一个令人兴奋的应用是组织工程，在组织工程中，细胞可以通过附着到图案化的基质上来排列。另一个例子：已经有许多癌症治疗的临床试验试图破坏肿瘤细胞的粘连，也许更好地理解粘连的机械力-化学可以为其他治疗进展指明方向。

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.