Nanoconfined Fluids

Pores a thousand times thinner than a human hair can now be routinely generated in silica, supramolecular assemblies, reverse micelles, zeolites, and even proteins. When a liquid like water is squeezed into such a channel, barely a few nanometers wide, nearly every molecule is touching a wall, and the familiar rules that govern liquids begin to break down. We use theory and computer simulations to explore how water and other fluids behave when trapped inside nanoscale silica pores. We can tune the pore's size, surface chemistry, and roughness in the simulation and watch how those changes alter the way molecules move, cluster, and react.

Why does this matter? Nanoporous materials are already at work in catalysts, water filters, drug-delivery capsules, and sensors. Designing better ones requires knowing the molecular rules that govern confined chemistry, such as does a chemical reaction run faster, slower, or differently inside a tiny pore than in bulk solution? An additional challenge is to understand how can we probe what happens in these pores? We are addressing this by simulating different kinds of spectra for nanoconfined fluids — validated by comparison with experimental measurements — and examining the configurations and motions of the fluid they report on.