Effect of pH on the Synthesis of Silica Sol-Gel Tetraethylorthosilicate-Trimethylchlorosilan (TEOS-TMCS)

Sol-gel synthesis of silica employing the co-precursor trimethylchlorosilane (TMCS) and precursor tetraethylorthosilicate (TEOS) was accomplished. The purpose this investigation to ascertain how pH affected properties synthetic silica. synthesized hydrophobic characterized using FTIR, TGA, GSA determine effect adjustment on functional group characters, thermal properties, pore morphology. ratio between TEOS/TMCS fixed at 75:25 varied (4, 6, 7, 8, 10) calcination temperature (without calcination, 300℃ 500℃). FTIR analysis showed that number C-H Si-OH groups in xerogel decreased with increasing temperature. Xerogel formed 6 provides highest stability among other pHs. results from BET revealed changes directly affect physical characteristics surface, making resulting gel network less rigid more susceptible shrinkage volume diameter atmosphere. Meanwhile, an alkaline medium, continuous condensation will occur so decrease. high imply 7 is ideal for preparing xerogels.