Nano-porous monolithic SiO2 aerogel as insulation material was prepared from silicon alkoxide as the precursor materials, followed by ethanol supercritical drying in this paper. In order to improve the mechanical properties of silica aerogel monoliths, the ceramic fibers were mixed in the pure aerogel, or integrating inorganic fiber materials as skeleton materials with low thermal conductivity supporting. Instron 5566, 5500R Material Testing Machine was used to measure the mechanical intensity. SEM was used to characterize the morphology of the silica aerogel monoliths. The thermal properties of the silica aerogels were determined by using the Hot Disk device. The results show that new type composite materials had a low effect on the thermal conductivities of the silica aerogel monoliths, but improved the mechanical intensity clearly. It made a great progress in the practical application of the SiO2 aerogel monoliths.

Surface modification is a process in which Si-CH3 groups of trimethylchlorosilane (TMCS) replace -OH groups on the inner surface of SiO2 aerogels, so the surface property of aerogels has shown hydrophobic performance which could be changed back to hydrophilic by 450 heat treatment. This aerogels with surface property controlled are prepared via sol-gel process with polyethoxydisiloxanes (E-40) used as precursor, and have typical porous structures dried at ambient pressure: high porosity (above 90 %), super specific surface area (about 1000 m2/g), low bulk density (down to 3.03 kg/m3) and average pore size is about 20 nm. This paper presents adsorption mechanisms in aerogels and illustrates that the adsorption capacity of aerogels is three or four times as much as that of activated carbon fiber (ACF) and granule of activated carbon (GAC). So SiO2 aerogels are potentially important to be used as absorbents being quite efficient to adsorb toxic substances.

A simple and clean route to synthesize nano-scale mesoporous silver-silica composite aerogels was described here. The composite aerogels were obtained by adding a silver colloid to an about-to-gel silica sol prepared and then dried in supercritical anhydrous ethyl alcohol. The silver colloid and composite aerogels with silver content of 0wt%, 0.5wt%, 1wt% and 3.5wt% were characterized by UV-visible absorption spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD) and N2 Brunauer-Emmett-Teller (BET). The results show that silver nanoparticles with size about 40nm are successfully impregnated into the spongy porous structure of silica. The surface area decreases from 845 to 443m2/g with the increase of silver content. And the nanoscopic surface and bulk properties of each component are retained in the solid composite.

In this paper, ordered mesoporous silica film as a novel antireflective coating was directly synthesized via evaporation induced self-assembly (EISA) process with cetyltrimethylammonium bromide (CTAB) as template surfactant. The mesoporous silica film exhibits ordered 2D hexagonal microstructure as demonstrated by transmission electron microscopy (TEM) and small angle X-ray diffraction (SAXRD). The average transmittance of the coated glass is about 98%, which indicates an increasing transmitted light of 7.5% in the wavelength between 400nm and 800nm. The mechanical performance and hydrophobicity tests prove that the films have excellent scratch resistance and long-time stability. The results of the characterizations and tests show that the film prepared by this convenient method would be very useful and promising for lots of commercial applications.

The adsorption properties of hydrophobic silica aerogels were studied. Polyethoxy- disiloxanes (E-40), ethanol (EtOH), hydrogen fluoride (HF) were used as silican precursor, solvent and catalyst, respectively, followed by solvent substitution and surface modification to prepare silica aerogels. Scanning electronic microscopy, nitrogen adsorption analyzer, contact angle measurement and Fourier transform infrared spectroscopy were used to characterize the structure and properties of silica aerogels. The conclusion is that the silica aerogels are with good hydrophobicity and the gas adsorption capacities is excellent for toxic gases such as benzene and carbon tetrachloride, which is 2~3 times higher than that of activated carbon fiber (ACF) or granule of activated carbon (GAC). Moreover, the adsorption capacity for organic solvent is 20-30 times of its own weight, which is much larger than that of GAC or Poly vinyl alcohol (PVA). In addition, the adsorption capacity of silica aerogels remains almost the same value after two times of adsorption- desorption processes, which means that the process is recyclable, low-cost and environmental friendly.