Abstract
Macroporous silica-polymer composite was fabricated from tetraethoxysilane (TEOS) and hydrophilic polymer such as polyethylene glycol (PEG), polypropylene glycol (PPG) and polyacrylic acid (PAAc) via sol-gel process. The effect of silica-polymer interaction and molecular weight of the polymer on the macroporous structure of the composite was investigated. The composite with PEG of 3×103 molecular weight hardly showed porosity, while with that of 7.5×103 or higher molecular weight, interconnected macroporous composite was formed through phase separation. The composite with PPG of 3×103 molecular weight and that with PAAc of 5×103 showed macroporous structure, which was like particle aggregation. On the other hand, FT-IR spectrum revealed that ether group in PEG formed hydrogen bond to silanol group of silica regardless of the molecular weight of PEG. PPG also formed hydrogen bonds, but PAAc did not. This inconsistency between macroporous structure and hydrogen bond formation is not directly explainable by effect of silica-polymer interaction through hydrogen bond on the generation of the macroporous structure. Microporous silica was obtained by calcinations of the composite. Higher PEG content of the composite resulted in mesoporous silica.
