Abstract: An acrylic acid/acrylic ester copolymer was employed as a dispersant for Bi4Ti3O₁₂ aqueous
suspensions. Surface chemistry of the suspensions was investigated by several techniques. Zeta-potential measurements showed that the isoelectric point
(IEP) of Bi₄Ti₃O₁₂ was shifted from pH=4 for pure Bi₄Ti₃O₁₂ to low pH regions in the presence of copolymer. FTIR spectra indicated that
copolymers adsorbed on Bi₄Ti₃O₁₂ surface via physical interaction. The adsorption amount varied with different copolymer content and reached
to the maximum values when 1.5wt% (dry mass base) copolymer was added, then decreased because of the deadsorption of the copolymer. The rheology of
Bi₄Ti₃O₁₂ aqueous suspensions was also studied. The results suggested that the stabilization of the suspensions was improved remarkably
by the adsorption of the copolymer on Bi₄Ti₃O₁₂ surface. The stability of the suspensions was attributed to the electrostatic mechanism
when the copolymer concentration was less than 1.5wt% and may be the depletion mechanism when the copolymer concentration was higher than 2.0wt%.

Key words: copolymer, bismuth titanate, adsorption, rheology