Model Studies of Reversibly Interacting Surfaces

PI建议研究表面和界面之间的相互作用，其中添加了表征良好的粘附分子分布。该分子基于嵌段共聚物，由位于固/液或液/液界面的疏水性和亲水性部分组成。实验旨在研究水介质中两个这样的界面之间的各种吸引相互作用。这些吸引相互作用是可逆的，并且是由嵌段共聚物亲水性部分的官能团之间的特定相互作用产生的。提议的实验包括研究附着在聚合物链末端的功能基团之间的疏水相互作用，附着在聚合物链末端的功能基团之间的氢键相互作用，以及生物物理学界已经很好地表征的模型受体/配体对之间的强氢键相互作用。实验将确定来自单个粘附分子的集体力在承载多个粘附基团的表面之间产生可量化的吸引力相互作用的方式。拟进行的研究将定义表面的作用、粘附分子的空间分布（均匀分布或聚集）的影响以及粘附分子在平面界面中的横向迁移。设计了一系列对界面相互作用能敏感的接触实验，这些实验跨越几个数量级。由于纳米科学和纳米技术的最新进展，分子水平的信息和适当设计生物材料或自组装系统所需的信息（相关的长度尺度通常在微米范围内）之间的研究提供了必要的联系。实验方法和理论模型的发展可以用来建立“纳米”和“微观”性质之间的联系，这将是本研究的一个重要成果。西北大学的科学家和他们的合作者也可以使用一个具有增强研究“软”材料能力的微力学实验室。此外，研究生和本科生将接受表面科学和力学方面的培训，以及聚合物科学的物理和化学方面的培训。

The PI proposes to study interactions between surfaces and interfaces to which well-characterized distributions of adhesion molecules have been added. The molecules are based on block copolymers consisting of hydrophobic and hydrophilic portions that are localized at a solid/liquid or liquid/liquid interface. Experiments are designed to study a variety of attractive interactions between two such interfaces in aqueous media. These attractive interactions are reversible, and result from specific interactions between functional groups attached to the hydrophilic portions of the block copolymers. Proposed experiments include studies of hydrophobic interactions between functional groups that are attached to the ends of the polymer chains, hydrogen-bonding interactions between functional groups that are attached to the ends of the polymer chains, and strong hydrogen-bonding interactions between a model receptor/ligand pair that has been well-characterized by the biophysics community. The experiments will determine the ways that collective forces from individual adhesion molecules result in quantifiable attractive interactions between surfaces bearing multiple adhesive groups. The proposed research will define the role of the surface, the effects of spatial distribution of adhesive molecules (uniformly distributed or clustered) and the lateral mobility of the adhesive molecules in the plane interface. A series of contact experiments have been designed that are sensitive to interfacial interaction energies spanning several orders to magnitude.The research provides a necessary link between the molecular-level information that is becoming increasingly available as a result of recent advances in nanoscience and nanotechnology, and the information that is needed for the appropriate design of biomaterials or self-assembling systems, where the relevant length scales are often in the micron range. Development of experimental methods and theoretical models that can be utilized to make this connection between 'nanoscopic' and 'microscopic' properties will be an important outcome of this research. A micromechanics laboratory with enhanced capabilities for studies of 'soft' materials will also be available to scientists throughout Northwestern University and the their collaborators. In addition, graduate and undergraduate students will be trained in aspects of surface science and mechanics, and in both physical and chemical aspects of polymer science.