Morphology and properties of silica/novolac hybrid xerogels synthesized using sol–gel polymerization at solvent vapor-saturated atmosphere

• Sol–gel polymerization in vapor of solvent saturated atmosphere is developed.
• Highly porous novolac–silica hybrid xerogels are successfully synthesized.
• Novolac–silica hybrid gel was dried in ambient condition with low shrinkage.
• Required time for preparation of gel reduced from 5 days to about 5 h.
• By incorporation of silica into the novolac xerogel structure, the pore size decreases.

Highly porous novolac–silica hybrid xerogels were successfully synthesized via the novel method of sol–gel polymerization in solvent vapor-saturated atmosphere. This method removes the need for supercritical drying and yields the hybrid xerogels with reduced shrinkage in comparison with conventional sol–gel process. Tetraethoxysilane (TEOS) was used as the precursor of silica-based inorganic phase. The chemical and structural characterization of the prepared hybrid xerogels were performed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis, respectively. Thermal and mechanical properties of the hybrid samples were investigated by differential scanning calorimetry (DSC), and compressive strength analysis. The resultant hybrid xerogels show a nanostructured colloidal hybrid network with high porosity (above 80%) and low density (below 0.25 g cm−3). Si mapping images shows the good distribution of silica phase throughout the hybrid structure.