Synthesis of polyaniline/spinel ferrites core-shell nanocomposites via sucrose auto-combustion and in situ polymerization

Herein, we prepared new nanocomposites from polyaniline (PANI) as a conductive polymer, and ferrites, MFe2O4 (M = Co2+, Cu2+, Mg2+, Ni2+, and Zn2+), as metal-oxide ceramics using sucrose sol-gel auto-combustion and in situ of polymerization. The prepared nanocomposites' structural, thermal, magnetic, and electrical/dielectric characteristics were investigated. X-ray diffraction (XRD) revealed the formation of the metal-oxide ceramics with weak crystallinity due to their coating in the amorphous structure of the PANI matrix. Transmission electron microscopy (TEM) images exhibited the wrapping of the entire metal-oxide ceramic particles by the PANI matrix, thus confirming the core-shell structure formation. Vibrating sample magnetometer (VSM) results showed drastic reductions in all ferrites' magnetization by their inclusion in the non-magnetic PANI matrix. The measured coercivity values showed a noticeable lowering in the presence of PANI. Besides, the thermogravimetric analysis (TG) technique indicated apparent increases in the thermal stability of the prepared nanocomposites compared to the pure PANI. Moreover, the electrical conductivity results indicated a change from metallic-like behavior for the pure PANI to the semiconductor by including the ferrites. Furthermore, by comparing the pure PANI, the dielectric properties of nanocomposites increased by the presence of ferrites, suggesting the suitability of the entire nanocomposites to be used in energy storage devices such as capacitors.