Alenka Luzar of the University of California, San Francisco, is supported by the Theoretical and Computational Chemistry Program for theoretical research directed toward assessing time scales of water dynamics in restricted environments on different length scales ranging from molecular events of hydrogen bond dynamics to kinetics of surface-induced evaporation on a mesoscopic scale. On the molecular scale, a new methodology to analyze hydrogen bond kinetics will be developed and applied to solutions of selected amino acids and alanine-based oligopeptides with varying chain length. This effort will utilize a combination of formal theory and molecular dynamics simulations, and will involve direct collaboration with neutron scattering experimentalists. On mesoscopic scales, the development of powerful umbrella sampling/Monte Carlo algorithms, in conjunction with a coarse-grained model of confined aqueous systems, will enable calculations of activation barriers for capillary evaporation at increased surface separations. This effort aims to extract a scaling law for the barrier height in order to bridge the gap between macroscopic measurements and limited-size model systems. Finally, in a related project, the occurrence of spontaneous liquid-vapor microphase transitions in a hydrophobic pocket will be explored in molecular dynamics simulations. Outcomes from this research are expected to impact disciplines concerned with dynamic aspects of interfacial water and hydrophobicity, ranging from colloids and materials science to biophysics.
Understanding the molecular aspects of water dynamics in restricted geometries is central to variety of problems in biophysics and cell biology. This research is expected to impact a number of fields where the effects of water are important, from the development of new bioactive compounds and improved optical fibers to research into biological structures such as proteins and self-assembling materials studied in nanotechnology. As well, research outcomes will assist in the design of surfaces that have optimized dewetting ability. Such surfaces are promising for practical applications such as rain-repellent coatings.
