Influence of silanols condensation on surface properties of micelle-templated silicas: A modelling study

The dehydration of model mesoporous silicas has been studied via molecular dynamics simulations. By progressively dehydrating the system, initially characterized by an even distribution of surface silanols, patches with hydrophobic or hydrophilic character are formed on the pores surface. It is found that the local concentration of silanols is strictly correlated to the local structure of pores surface, namely hydrophobic and hydrophilic patches are located in high- and low-curvature surface regions, respectively, in line with experimental evidences. Simulations suggest that the microscopic origin of both the uneven Si-OH distribution and the pores surface deformation should be related to the dehydroxylation process, which is governed by interactions among the silica matrix.