Study of Silica Aerogels Prepared by Sol-gel Process Dried at Ambient Pressure

A new method to produce hydropbic silica aerogels was introduced.SiO2 alcogels were prepared by tetraethoxysilane(TEOS)via sol-gel process,then the surface was modified by hexmethyldisilazane(HMDZ),and finally dried at ambient pressure.The structure and properties of the silica aerogels have been investigated by SEM,FTIR,BET.It has been observed that the aerogels,which are made up of uniform spherical nanoparticles with diameters of about 13 nm,are of coherent network structures.The diameter of the pore sizes is in the range of 2-110 nm,and the density of the aerogels is low(110 kg/m3).The specific surface area of the aerogels can be as high as 827.56 m2/g.The aerogels show an excellent hydrophobic feature.