Effect of Different Reaction Solvents on the Hydrophobic and Structural Properties of Silica Cryogels
The experimental results on the microstructural and physical properties of the TEOS-based silica cryogels have been reported. The cryogels were produced by two-step sol-gel process followed by vacuum freeze drying. The wet gels were synthesized via acid-base catalysis using tetraethoxysilane (TEOS) as a silica precursor, the different solvents containing ethanol (EtOH), methanol (MeOH) and tert-butanol (TBA), the molar ratio of TEOS / solvent were varied from 1:6 to 1:13. Further, the microstructure and specific surface area of the cryogels were analysed by Scanning Electron Microscopy (SEM) and nitrogen absorption/desorption isotherms. The hydrophobicity of the cryogels was studied by contact angle. It was found that the highest specific surface area (1040.17 m2 / g) was obtained with the solvent of MeOH. The lowest density (0.074 g/cm3) was acquired with the solvent of EtOH.
Yuan Ming Huang
L. F. Su et al., "Effect of Different Reaction Solvents on the Hydrophobic and Structural Properties of Silica Cryogels", Materials Science Forum, Vols. 663-665, pp. 1238-1241, 2011