Stability of suspensions of ferroelectric BaTiO3 particles in hydrocarbon carrier liquids

The stability of suspensions of ferroelectric (BaTiO₃) nm-particles, using heptane as carrier liquid and oleic acid as stabilizer, is investigated by means of electrooptic Kerr rotation and optical transmittance. On suspension up to 0.006 solid volume fraction, with permanent dipole moments existing at 5 nm<r<20 nm (14 mC/cm² at 20 nm), 10-90% reversible changes in the transmittance were observed while the Kerr rotation was apparently unaffected. This can be explained by a field-induced reversible agglomeration of about 5% of the particles. Irreversible agglomeration is also observed for high solid volume fractions and low stabilizer content