The effect of synthesis parameters on pore diameter of superhydrophobic silica aerogel prepared at ambient pressure

Abstract

Silica aerogels were prepared by the sol-gel method and dried at ambient pressure with sodium silicate precursor. The prepared aerogel is superhydrophobic. The effect of various synthesis conditions on pore structure and diameter was investigated. The results of N2 adsorption-desorption isotherms, BET theory, BJH method, and field emission scanning electron microscopy images showed that by changing the surface modification method, the porosity of the samples changes. The order of increasing the average pore diameter for different protic solvents is isopropanol < methanol < ethanol. The specific surface area and total pore volume also increase with the increasing concentration of citric acid citric. The sample surface modified with HMDZ has smaller average pore diameters and total pore volume than the sample surface modified with TMCS. With increasing temperature, the average pore diameter and total pore volume increase, and the BET surface decreases.