Preparation and Characterization of Core–Shell‐Structured Polyaniline Nanocomposites With Combined Electrical Conductivity, Magnetic Properties, and Fluorescence Performance

A Ni 0.5 Zn 0.5 Fe 2 O 4/ SiW 11 Ni/PANI core–shell nanocomposite was prepared via one‐step inverse microemulsion polymerization, achieving integrated control of conductivity, soft magnetism, and blue photoluminescence. Spinel Ni–Zn ferrite (∼15 nm, 59.95 emu/g) was first synthesized by ultrasonic co‐precipitation–reflux. A Keggin‐type nickel‐substituted silicotungstate heteropoly salt served as a bifunctional dopant, enhancing PANI's conductivity and providing blue‐light emission. During microemulsion polymerization, heteropolyanions intercalated into protonated PANI chains, uniformly coating the ferrite surface to form a core–shell structure. XRD, TEM, FT‐IR, VSM, and other techniques confirmed the formation of uniform spherical particles (30–70 nm). The optimal sample exhibited a conductivity of 4.74 × 10 −1 S/cm, along with good soft magnetism and stable blue emission. Lewis acid–base interactions, temperature‐sensitive magnetic response, and the effect of ferrite loading on electrochemical transport were systematically verified. An optimal ferrite addition of 1.5 g significantly improved the electrode conductive network and ion diffusion kinetics. This mild one‐step method integrates magnetic, electrical, and optical functions. The multifunctional nanocomposite shows potential for miniaturized energy storage electrodes, multimodal bioimaging, and wide‐temperature magnetic sensors.