Molecular study on the formation of porous silica networks in an all-atom-approach

Abstract

Reactive molecular dynamics (RMD) is used to describe porous silica networks starting from orthosilicic acid molecules. The ReaxFF [1] uses empirical interatomic potentials to calculate bond order potential to describe chemical bonding without the use of time extensive and computationally expensive quantum mechanical calculations. The condensation reactions are simulated resulting in a network of silica and dissociated water molecules, of which the latter are removed gradually from the system. This follows the condensation, gelation, and mimics the drying process as observed in silica aerogels. The structural evolution of the silica backbone in the network is investigated through the partial pair distribution function of the Si-O bond. RMD simulations offer extended insights over experimental procedures to investigate the reactions and the resulting structure because they present a detailed insight into the atomic-scale phenomena that underlie the formation of the gel network. The resulting model systems will be investigated for their structural, mechanical and thermal properties.