Long and Medium-Term Research: Studies of the Effect of Polymer/Solvent Self-Diffusion and Thermodynamics Coupling on Mutual-Diffusion

该奖项是根据长期和中期研究， 外国卓越中心计划，使美国 科学家和工程师将进行三到十二个月的 在国外被证明卓越的研究中心进行研究。 的 该计划的奖项提供了联合研究的机会， 利用独特或互补的设施、专门知识和 国外的实验条件。 该奖项将支持为期十二个月的博士后研究访问 约翰·M博士宾夕法尼亚州立大学的Zielinski工作 Hans Sillescu博士在Institut fur 美因茨大学物理化学系。 扩散速率的知识在设计适当的 用于许多应用的产品包括：（1）脱挥发分， (2)药物的时间控制释放，（3）涂料的干燥， 涂层，（4）包装或屏障膜和（5）分离 流程. 尽管聚合物/溶剂扩散的重要性 系数，然而，这种类型的数据很少， 可在文献中获得，特别是在不同的溶剂下 浓度的 由于越来越强调减少 商业加工的排放量， 此时聚合物体系中的渗透剂分子是必要的 如果不是必要话。 相互扩散过程固有地与聚合物耦合， 溶剂自扩散及其热力学相互作用。 的 脉冲梯度自旋回波（PGSE）核磁共振 (NMR)技术和全息光栅先前已经 用于测量溶剂自扩散系数。 只 然而，最近，仪器的进步使这些 也可用于解决聚合物自扩散的技术。 虽然直接获取数据非常重要， 还需要补充理论研究， 聚合物/溶剂系统的扩散特性可以 预测先验。 自系数和互系数的耦合 是现有扩散理论中最薄弱的环节 因此， 深入的实验和理论研究 个体自扩散系数和 提出了聚合物/溶剂互扩散系数。 该奖项的建议提供资金的津贴为12 个月

This award is under the Long and Medium-Term Research at Foreign Centers of Excellence Program, which enables U.S. scientists and engineers to conduct three to twelve months of research abroad at research centers of proven excellence. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twelve-month postdoctoral research visit by Dr. John M. Zielinski of Pennsylvania State University to work with Professor Doctor Hans Sillescu at the Institut fur Physikalische Chemie der Universitat Mainz. Knowledge of the diffusion rate is essential in designing adequate products for numerous applications including: (1) devolatilization, (2) medicinal time-controlled release, (3) drying of paints and coatings, (4) packaging or barrier membranes and (5) separation processes. Despite the importance of polymer/solvent diffusion coefficients, however, proportionately little data of this type are available in the literature, particularly at varying solvent concentrations. Due to the escalating emphasis on reducing emissions from commercial processes, diffusion studies of penetrant molecules in polymer systems at this time are warranted if not essential. Mutual-diffusion processes are inherently coupled to polymer and solvent self-diffusion and their thermodynamic interaction. The Pulsed Gradient Spin Echo (PGSE) nuclear magnetic resonance (NMR) technique and holographic grating have previously been employed to measure solvent self-diffusion coefficients. Only recently, however, have advances in instrumentation rendered these techniques viable for addressing polymer self-diffusion as well. Although acquiring data directly is extremely important, complementary theoretical studies are also required so that diffusional characteristics for polymer/solvent systems can be predicted a priori. The coupling of the self-and mutual coefficients is the weakest link in existing diffusion theories. Consequently, an indepth experimental and theoretical study of the relationship between the individual self-diffusion coefficients and the polymer/solvent mutual-diffusion coefficient is proposed. This award recommendation provides funds for a stipend for twelve months.