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. ***
