Shaped tetragonal barium titanate (BaTiO3) particles were prepared by the s
ol-emulsion-gel method with systematic variation of the concentration of a
non-ionic surfactant in the organic phase ("oil phase") of water-in-oil (w/
o) emulsions above or below the critical micelle concentration (CMC). An ac
etate-based sol with equivalent oxide ratio BaO : TiO2 = 1 : 1 was selected
for the study. Micelle formation of the surfactant and their self-aggregat
ion apparently played an important role in controlling the shape and size o
f the droplets and accordingly shape and size of the final barium titanate
particles resulting therefrom. Transmission electron microscopy (TEM) revea
led that with low concentration of the surfactant (2-5 vol%) ill-formed sph
eres were obtained. Spherical particles were formed with increasing the sur
factant concentration to 7 vol%. At 12 vol% of the surfactant, rod-like par
ticles were first found to form, which with further increase in surfactant
concentration to 15-20 vol%, gradually transformed to cube-like/lamellar ty
pe particles. Attempts have been made to explain the various particle shape
s in terms of surfactant aggregation.