Comb polymer architecture, ionic strength, and particle size effects on the BaTiO₃ suspension stability

We investigate the stability of aqueous barium titanate suspensions as a function of dispersant architecture, ionic strength, counterion valency, and particle size. Both pure polyelectrolytes, poly(acrylic acid) and poly(methacrylic acid) (PMAA), and comb polymer dispersants composed of a PMAA backbone with methoxy-poly(ethylene oxide) (mPEO) teeth of varying molecular weights are studied. While each dispersant imparts stability to barium titanate suspensions at low ionic strength (<∼0.01M), only the PMAA-mPEO comb polymer with the longest teeth provides stability at higher ionic strengths independent of particle size and counterion valency. Our findings provide new insight into the design of comb polymer dispersants for stabilizing aqueous ceramic suspensions over a broad range of processing conditions.