Characterizing Hydration at Nanostructured Surfaces – Applications to Materials Design and Protein Interaction Prediction

By understanding the molecular underpinnings of solvation (of water and other liquids) adjacent to complex nanostructured surfaces, that is, surfaces with chemical patterns and/or texture at the nanoscale, our group strives to inform the design of the next generation of advanced materials, and to facilitate efficient and accurate prediction of biomolecular interactions and assembly. In this presentation, I will provide examples of our recent work in both of these areas.

I will first highlight our efforts towards the rational design of superhydrophobic surfaces, that is, hydrophobic surfaces, which utilize roughness to impede the wetting of the surface. While such surfaces display numerous desirable properties, including water-repellency, self-cleaning, and interfacial slip, a key bottleneck in the widespread adoption has been the irreversible loss of superhydrophobicity, which accompanies the wetting of the surface texture at elevated pressures. Using molecular dynamics simulations in conjunction with enhanced sampling techniques, we discovered that water density fluctuations play a crucial role in the dewetting of the surface texture, stabilizing a non-classical dewetting pathway, which involves a number of transitions between distinct dewetted morphologies, and lower free energetic barriers to dewetting. Importantly, we were able to use these insights to augment the surface texture, and demonstrate for the first time, that the barriers to dewetting on textured surfaces could be eliminated altogether, thereby allowing the surface to spontaneously recover its superhydrophobicity.

I will then describe our efforts in uncovering the role that water plays in mediating the interactions and self-assembly of complex molecules, including proteins, peptides, and surfactants. The extent to which the inherent structure of water is perturbed by these complex molecules, determines the thermodynamics and the kinetics of their assembly. However, accurately characterizing perturbation is challenging, because proteins have incredibly complex surfaces that disrupt the inherent structure of water in countless different ways, depending not only on the chemistry of the underlying protein surface, but also on the precise topography and chemical pattern of amino acids. I will discuss our recent efforts on quantitatively characterizing this disruption of water structure, with the goal of using this information to efficiently predict the interfaces through which these complex monomers interact with one another and self-assemble.