Abstract
Spin-coating method is a simple way to synthesize nanostructured silica films. However, the thin films by spin-coating have low thermal stability because the reactions proceed at room temperature. In this study, we have developed a vapor treatment using a silica source for spin-on nanostructured silica films to improve the structural stability. The vapor treatment promotes condensations of silanol groups. The silica wall is densified and hardly contracts under a calcinations process. This indicates that vapor treatments effectively enhance structural stability. We have studied effect of vapor treatments on mechanical strength and hydrothermal stability of the nanoporous silica films prepared from tetraethoxysilane (TEOS)/Brij 30 (C12(EO)4) mixtures. The results of pressure tests and hot water-resisting tests show that the vapor-treated films exceed non-treated films in mechanical strength and hydrothermal stability. The vapor-treated nanoporous silica films are promising materials as low-k films with high mechanical strength and high porosity.
