Structure and Chemical Interactions at Model Polymer Interfaces

分子和聚合物界面的结构和化学关联将在两种类型的材料系统中产生：1)柔性链分子和聚合物作为薄膜吸附在固体表面上；2)无机薄膜，特别是金属，（在真空中）沉积在分子和聚合物表面上。通过使用自组装单层制备的定义良好的底物，以及精确控制所选官能团的阵列，并通过应用先进的定量表征工具，对单层-亚单层水平的分子特征敏感，所有相关性将被尽可能定量地驱动。钉住晶格的关键概念，定义为当界面形成时吸附或成核发生的特定位置阵列，将上述两个系统的实验联系起来，并将指导本工作的过程。在柔性链分子吸附的情况下，将发展出由钉住晶格决定的平面内排列与化学键合（势井深度）以及吸附（钉住）位点的相关迁移动力学与在吸附（自组装）链组装相中形成的面外结构之间的相关性。这些关联将通过发展一个简单的理论框架统一起来，该理论框架将集中于描述自由体积（缺陷构型）的分布。在金属原子沉积（真空中）的情况下，将开发出将成核（钉住）位置（官能团）分布及其化学（金属-有机）与金属膜形态联系起来的相关性。这项特别的努力将集中在真空沉积实验研究上，由原位红外光谱、x射线光电发射和光谱椭偏仪监测，但也将包括与他人合作的有限理论研究。上述努力的预期结果是发展一个理论和实验上一致的框架，用于设计广泛变化的，精确定义的功能化单层，并用于理解从近平衡分子吸附到高度放热金属原子化学吸附的广泛吸附的吸附/化学吸附性质。该研究将有效地将这些结果与实际材料科学问题联系起来，包括聚合物表面和界面特性，如粘附性和润湿性，以及聚合物的金属化。＊＊＊

9310151 Allara Correlations of structure and chemistry at molecular and polymer interfaces will be generated for two types of materials systems: 1) flexible chain molecules and polymers adsorbed as thin films at solid surfaces and 2) inorganic films, specifically metals, deposited (in vacuo) onto molecular and polymer surfaces. All correlations will be driven to be as quantitative as possible by the use of well-defined substrates prepared from self-assembled monolayers with precisely controlled arrays of selected functional groups and by the application of advanced, quantitative characterization tools, sensitive to molecular features at the monolayer-submonolayer level. The key concept of a pinning lattice, defined as the specific array of sites upon which adsorption or nucleation takes place when an interface is formed, interrelates the experiments with the above two systems and will guide the course of this work. In the case of flexible chain molecule adsorption, correlations will be developed which relate the in-plane arrangements, dictated by the pinning lattice, with the chemical bonding (potential well depth) and the associated dynamics of mobility of the adsorption (pinning) sites with the out-of-plane structures which develop in the adsorbed (self- assembled) chain assembly phases. These correlations will be unified by the development of a simple theoretical framework which will focus on attempts to describe the distribution of free volume (defect configurations). In the case of the metal atom deposition (in-vacuo), correlations will be developed which relate the nucleation (pinning) site (functional groups) distributions and their chemistry (metal-organic) to the morphology of the metal films. This particular effort will focus on experimental in-vacuo deposition studies, monitored by insitu infrared spectroscopy, x- ray photoemission and spectroscopic ellipsometry, but also will include limited theoretical studies in collaboration with others. The expected outcome of the above efforts is the development of a coherent framework, both theoretical and experimental, for designing widely varying, precisely defined functionalized monolayers and for understanding the adsorption/chemisorption properties over a wide range of adsorbates from near-equilibrium molecular adsorption to highly exothermic metal atom chemisorption. The research will be designed to efficiently relate these results to practical materials science issues involving polymer surface and interface properties such as adhesion and wetting and to metallization of polymers. ***