The microstructural properties of nanosized TiO2 micelles, generated in situ in a water-in-oil (w/o) microemulsion composed of water, dioctyl sulfosuccinate sodiun salt (AOT) and cyclohexane, by controlled hydrolysis of TiCl4, were investigated. The samples were characterized by analytical electron microscopy combining electron diffraction. TiO2 film consisted of isotropic grains of anatase. The grain sizes were 5 nm, which is in agreement with the average grain size [R], previously obtained by grazing-incidence wide-angle X-ray diffraction (GIWAXD), of 5.0 +/- 1.3 nm. Grains were gathered in a number of clusters, differently oriented with respect to the electron beam. (C) 2000 Elsevier Science B.V. All rights reserved.