화학적 산화 중합을 통한 코어-쉘 구조의 아연 페라이트/폴리피롤 유/무기 복합재의 합성 및 전기/자기 유변물성 연구

초록

In this paper, a material having a core-shell structure was successfully synthesized by coating polypyrrole (PPy) on zinc ferrite (ZnFe2O4) through chemical oxidation polymerization. [1] Synthesized core-shell structured ZnFe2O4/PPy organic/inorganic composite particles were used as materials for electrorheological (ER) fluid and magnetorheological (MR) fluid. [2] We called it as an Electro/magneto rheological (EMR) fluid. Zinc ferrite was synthesized using a solvothermal method, and PPy was coated on zinc ferrite using a common ion effect. The morphology of the synthesized ZnFe2O4/PPy particles was confirmed by scanning electron microscopy and transmission electron microscopy. And the chemical structure was confirmed by Fourier transform infrared spectroscopy. Dispersing the synthesized particles in silicone oil, electrorheological (ER) and magnetorheological (MR) properties were measured by a rotational rheometer, and it was confirmed through optical microscopy that chain-like structure was formed by an external electric field in the fluid. Steady-state tests and oscillatory tests were conducted under various electric and magnetic fields. When the electric field and magnetic field were applied, it was confirmed that the flow curve was fitted well to the Bingham fluid model, and the significant increment of shear stress was observed by the electric and magnetic fields. It indicated that phase transition occurs in both electric and magnetic fields, so it is expected as a material for EMR fluids that respond to both electric and magnetic fields and can be used as candidates for various applications.