Effect of Organic Modification Temperature on the Microstructure of Nanoscale Titania

Nanoscale titania aqueous dispersion was prepared firstly, and then nanoa2titania particles was transfered into methylbenzene in which stearic acid was dissolved from water by distillation so that the surface modification was carried out in organic system. Nanoscale titania was modified with stearic acid at different temperatures.The samples were characterized by Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscope (XPS), thermogravimetry(TG), derivative thermogravimetry (DTG) and transmission electron microscopye(TEM). The results show that stearic acid is bound on the surface of nanoscale titania by bidentate structure, and even monolayer coverage is obtained. With modification temperature increasing, the crystallite size of nanoscale titania increase, the mass fraction of chemisorbed stearic acid on the surface of nanoscale titania decrease, and the thickness of stearic acid layer changes from 1nm to 2-3nm.The modification temperature has little effect on interactions between stearic acid and titania.