Magnetite/Poly(ortho-anisidine) Composite Particles and Their Electrorheological Response

Abstract

Magnetic and semiconducting Fe3O4/poly(o-anisidine) (POA) core/shell composite particles were fabricated by an oxidation process using Fe3O4 synthesized separately. The dispersion stability in a liquid medium and the electrical conductivity of synthesized particles were improved because of the conductive POA polymeric shell. The morphological, microstructural, compositional/elemental, and thermal behaviors of the particles were characterized using SEM with energy dispersive X-ray spectroscopy, TEM, XRD, and thermogravimetric analysis, respectively. A smart electro-magneto-rheological suspension containing Fe3O4/POA particles with two functionalities, magnetism and conductivity, was prepared. Its electrorheological properties were investigated at different electric field strengths using a rotational rheometer. Without an electric field, the sample demonstrated typical Newtonian fluid behavior, as expected. However, while under the electric field, it exhibited a solid-like behavior, and the dynamic (or elastic) yield stress of the ER fluid increased linearly as a function of the electric field strength in a power-law function with an index of 2.0, following the polarization mechanism.

Positional Isomeric Effects on the Physicochemical Properties of Polymeric Matrix and Polymer@TiO2 Nanocomposites

“…By contrast, PPA@TiO 2 presented a higher mass loss of 32%. These results indicate that the interaction between the TiO 2 particles and polymer chains may have limited the thermal motion of TiO 2 particles and provided thermal stability to nanoparticles [43].…”

“…Moreover, all products had a spherical morphology, which was likely induced by absorbing monomers on the surface of TiO 2 through H-bonding and electrostatic attraction after HCl acidified the TiO 2 spheres. The TiO 2 surface was modified during the acidification stage, and no other surface treatments were necessary [43]. Moreover, TEM images of the nanocomposites indicate that TiO 2 particles were successfully dispersed into the polymer matrix [47].…”

Poly(o‐anisidine), its composites, derivatives and applications: A review

“…An effective technique for the synthesis of various polymers is chemical oxidative polymerization. The monomers solution is incorporated with an oxidizer and a dopant at 0–5°C with constant stirring during this process 23 …”

“…An effective technique for the synthesis of various polymers is chemical oxidative polymerization. The monomers solution is incorporated with an oxidizer and a dopant at 0-5 C with constant stirring during this process 23 The POA was prepared through chemical oxidative polymerization, O-anisidine as a monomer, and commonly used initiators such as potassium iodate (KIO 3 ), 24 ammonium persulfate (NH 4 ) 2 S 2 O 8, 25 potassium persulfate (K 2 S 2 O 8 ), 26 potassium dichromate (K 2 Cr 2 O 7 ), 27 quinolinium fluorochromate (QFC) [C 9 H 7 NH(CrO 3 F)], 28 etc. This technique provides a thick coating or powder of POA which is segregated through the remaining mixture by filtration at a predetermined time and afterward washed with purified water, methanol and acetone until a steady mass is reached.…”