Theoretical investigation of solvation and inter-chain interactions for phosphate ester dispersants on tetragonal BaTiO3 (001) in non-aqueous solvents: An ab initio molecular dynamics simulation approach

Tetragonal BaTiO3 is a key material for manufacturing multi-layer ceramic capacitors (MLCCs), and a highly dispersed BaTiO3 suspension, where the surfaces are conjugated by phosphate ester dispersants, is an essential technology for the production of ultra-thin films and small-sized ceramic capacitors. Therefore, understanding the interactions of conjugated polymers with solvents is critical to designing improved dispersants and solvents for commercial MLCC applications. In this work, we theoretically investigate the solvation and inter-chain interactions of mono-alkyl and ethoxy phosphate esters under methanol, ethanol, isopropanol, 1-butanol, and toluene, on tetragonal BaTiO3 (001) using the ab initio molecular dynamics (AIMD) simulations. Our results show that the total number of solvent molecules surrounding mono-alkyl and ethoxy phosphate esters decreases in the order of methanol > ethanol > isopropanol > 1-butanol > toluene, indicating that solvation via van der Waals forces and hydrogen bonding declines with increasing the hydrophobicity of solvent molecules. Also, the solvation interaction energy has a linear correlation with the experimental differential of zeta potential, suggesting that the calculated energy is associated with electrostatic environment at the dispersant/solvent/BaTiO3 interface. Therefore, the solvation interaction energy is an important factor that describes the liquid-solid interfaces as well as a dispersion stability of BaTiO3 suspension.

Automated summary

The interaction between conjugated polymers and BaTiO3 in different solvents was studied. The results showed that the degree of solvation through van der Waals forces and hydrogen bonding decreased with the increasing hydrophobicity of the solvents. In addition, the solvation interaction energy had a linear correlation with the experimental differential of zeta potential, indicating that the calculated energy was associated with the electrostatic environment at the dispersant/solvent/BaTiO3 interface.