Solvent dispersible nano-silica powder was prepared by a dual-step sol-gel process: first, SiO_2nanoparticles were synthesized through acid-catalyzed hydrolysis and condensation of tetraethyl orthosilicate in 2-propanol aqueous solution. Then, the particles were surface-modified by means of the capping agent trimethylethoxysilane (TMES). The formed product, termed TSiO_2 nanopowder, was dispersible in many organic solvents, and the dispersibility was found to depend on the amounts of TMES bounded to the SiO_2 nanoparticles. FTIR spectra of TSiO_2 samples confirm Si-O-Si linkage being formed between TMES and SiO_2 through the capping reaction. The sizes of TSiO_2 dispersed in various solvents, as determined by dynamic light scattering (DLS), fell largely over the range 2-20 nm for solvents with solubility parameters of 16-29.6 MPa^(1/2). TEM imaging of the nanoparticles indicated that they were well separated with the largest identifiable size of ~10 nm, agreeing with the results obtained from DLS.
Journal of Applied Science and Engineering 19 (4), pp.401-408