Static and dynamic properties of the water/amorphous silica interface: a model for the undissociated surface

Abstract

Amorphous silica-water interfaces are found ubiquitously in nanoscale devices, including devices fabricated from silica as well as from silicon that acquire a surface oxide layer. The surface silanol groups serve as hydrogen-bonding sites for a variety of chemical species, and their reactivity enables convenient chemical modification, making silica surfaces strategic in bio-sensing applications. We have extended the popular BKS and SPC/E models for bulk silica and water to describe the hydrated, hydroxylated amorphous silica surface. The parameters of our model were determined using ab initio quantum chemical studies on small fragments. Our model will be useful in empirical potential studies, and as a starting point for ab initio molecular dynamics calculations. At this stage, we present a model for the undissociated surface. Our calculated value for the heat of immersion, 0.6 Jm −2 , falls within the range of reported experimental values of 0.2-0.8 Jm −2 . We also study the perturbation of water properties near the silica-water interface. The disordered surface is characterized by regions that are hydrophilic and hydrophobic, depending on the statistical variations in silanol group density. We report non-equilibrium molecular dynamics simulations of Poiseuille flow of water near an amorphous silica surface.

Water structure at solid surfaces and its implications for biomolecule adsorption

“…This would not only remove our reliance on empirical force fields, but also provide a general methodology for handling rough and atomically-detailed surfaces (anisotropic geometries). Research into such methods has already demonstrated success, [149][150][151][152] but the associated computational expense limits the data to relatively short (sub-nanosecond) trajectories. As advances in computer technology and algorithms continues to progress and we are able to get an increasinglyrefined view of interfacial water structure, the next frontier would be to provide the same detailed treatment for ions, surfactants, and large solutes as peptides and proteins.…”

Molecular Dynamics Study of the Electric Double Layer and Nonlinear Spectroscopy at the Amorphous Silica–Water Interface

“…Na Cl (28) either from the PB equations or from an MD trajectory. Equations 26 and 27 match the total number of ions and total ion charge, respectively, between MD and the PB theory in the region |z| < z d .…”

Understanding small biomolecule‐biomaterial interactions: A review of fundamental theoretical and experimental approaches for biomolecule interactions with inorganic surfaces

“…In recent years, forcefield based simulation techniques have been developed and applied in order to model the oxide/water interface,123–149 especially the TiO 2 ‐water interface 96, 150–155. The interaction of transition metal oxide surfaces with water, including dissolution and inorganic/organic species adsorption, is now being described.…”