Enhancement on electric responses of BaTiO3 particles with polymer‐coating

To enhance electric response by polymer coating, BaTiO₃/polymer shell–core composite particles were prepared by emulsion polymerization with polyimide, chitosan, polystyrene, polyacrylic acid, and polyacrylamide. Their micro structure was characterized by transmission electron microscopy, Fourier transform infrared, and automatic X‐ray diffraction, their properties were investigated using optical contact angle and dielectric constant, and their electric responses were studied indirectly by dynamic viscoelasticity analyzer. The results showed that BaTiO₃ cores remained in cubic, the surface hydrophilic of the particles changed as follows: BaTiO₃ > BaTiO₃/PI > BaTiO₃/PAM > BaTiO₃/Chitosan > BaTiO₃/PAA > BaTiO₃/PS, and the dielectric constants of the particles varied with the order of that BaTiO₃ > BaTiO₃/PI > BaTiO₃/PAM > BaTiO₃/Chitosan > BaTiO₃/PAA > BaTiO₃/PS. Eventually, the particles' electric response activities exhibited the order of BaTiO₃/PI > BaTiO₃/PAM > BaTiO₃/Chitosan > BaTiO₃/PAA > BaTiO₃/PS > BaTiO₃. Furthermore, the electric response of the particles showed a chief dependence on polymer‐coating, surface hydrophilic, and dielectric constant. As a result, BaTiO₃ particles' electric response was much enhanced by polymer‐coating, and their compatibility to aqueous continuous phase was ameliorated. For the BaTiO₃/polymer particles, fine surface hydrophile and high dielectric constant dominated the strong response to electric field. Ultimately, BaTiO₃/PI and BaTiO₃/PAM particles possessed the strongest electric response in the five composite particles. The conclusion suggests an effective approach to prepare excellent hydrous electrorheological elastomers. POLYM. COMPOS., 34:897–903, 2013. © 2013 Society of Plastics Engineers