Preparation of silica gels in electrostatic field

The investigation is focused on the pore distribution and morphology of the gels prepared under electrostatic fields from hydrochloric acid-catalyzed TEOS (tetraethyl orthosilicate) systems (acetone as solvent). Hydrochloric acid of 1.0 and 0.6 M, and electrostatic field of 3kV/52mm and 3kV/8mm were adopted. The sols were put in electrostatic fields after certain minutes of stirring, and the acquired wet gels were moved away for aging when gelation finished. After aging in sealed containers for a week, they were dried in ambient condition, and additionally some of them were calcinated at 600°C after drying. SEM analyses showed that these xerogels had variant pore distribution or distinct morphological characteristics, which were related to the direction of electric field and could be attributed to the influence of electrostatic field on the redistribution of colloidal particles and water, and that xerogels with gradient pore distribution might be expected if proper parameters were adopted.