Calendar
Water in Confined Spaces
April 3, 2007 (3:30PM - 4:30PM)
- Speaker: Pablo G. Debenedetti - 2007 Reilly Lecturer (Department of Chemical Engineering, Princeton University)
- Location: 131 DeBartolo
Confining surfaces that contain thin water films are ubiquitous in biology, materials science and engineering. Understanding the effects of surfaces on the dynamics, structure and thermodynamics of proximal water is therefore of interest in applications ranging from lab-on-a-chip technologies to the inhibition of corrosion. Molecular simulation is a powerful tool for probing the behavior of water in nano-scale confinement. Hydrophobic surfaces induce a rich phase behavior, which includes a novel ice phase, capillary drying, and liquid-liquid coexistence. Water in hydrophobic confinement is a "soft" material whose properties depend sensitively on pressure. Surfaces with patterned hydrophobicity and hydrophilicity reveal several interesting phenomena, such as geometry-dependence of hydrophobicity and pressure-induced blurring of distinctions between hydrophobic and hydrophilic hydration. Melittin, a bee-venom protein that self-assembles into tetrameric units, is a convenient system for studying water in biological confinement. Water bounded by melittin dimers shows behavior intermediate between that which occurs near purely hydrophobic and hydrophilic surfaces. Capillary drying is highly localized and requires a close approach between melittin dimers. These results have implications for biological self-assembly, the phase behavior of metastable water, and the design of superhydrophobic surfaces.
