Optimized phosphate ester structure for the dispersion of nano-sized barium titanate in proper non-aqueous media

Suspension stability of nano-sized (50 nm) barium titanate (BaTiO3) with different non-aqueous solvents and phosphate esters has been investigated by means of zeta potential, hydrophilic lipophilic balance (HLB) value, adsorption, sedimentation and viscosity measurements. Without dispersants addition, the proper viscosity of the non-aqueous solvent is an essential dispersion factor for stabilizing the nano-sized BaTiO3 suspensions, such as 1-methoxy-2-propanol. On the other hand, three typical phosphate esters were synthesized and used as dispersants, including mono-alkyl, di-alkyl (Di-), and mono-ethoxy (EO-) type. Due to the soft and appropriate molecular length of ethoxy group, the 2-ethoxy ethyl dihydrogen (1EO-) phosphate esters not only shows the efficient adsorption over the nano-BaTiO3 powders, but also superior dispersion properties in high solid concentration (40 wt.%) status.