Synthesis of nanometer-sized TiO2 particles by a microemulsion method

Nanometer-sized titania particles have been prepared by chemical reactions between TiCl4 solution and ammonia in reversed microemulsion systems. Cyclo hexane and a mixture of poly (oxyethylene)(5) nonyle phenol ether and poly (oxyethylene)(9) nonyle phenol ether with weight ratio 1:1 are used as oil phase and nonionic surfactant, respectively. The product is characterized b y transmission electron microscopy, Raman spectroscopy, differential therma l and thermogravimetric analyses. Size distribution of particles determined from electron micrographs fits well with a lognormal function whose values for median and width are 5.4 nm and 1.4 nm. The crude product is amorphous and transforms into anatase heated at temperature from 200 to 750 degrees C, into rutile at temperatures higher than 750 degrees C. (C)1999 Acta Meta llurgica Inc.