Star-Like Polyaniline Nanostructures via Core-First Grafting and Strontium Cobalt Oxides Doping: Morphology and Conductivity Enhancement

Abstract Branched PANI architectures have recently gained attention for their ability to overcome the transport limitations of traditional linear polyaniline (h-PANI) by forming more efficient conductive networks. Accordingly, star-like polyaniline (s-PANI) was synthesized via a core-first oxidative grafting strategy using 1,3,5-tris(4-aminophenoxy)benzene (TAPOB) as a trifunctional initiator. Linear h-PANI was prepared under comparable conditions as a reference. Structural characterization via FTIR and 1 HNMR confirmed successful covalent branching in s-PANI, and SEM revealed interconnected nanofibrous network distinct from the rod-like morphology of h-PANI. To evaluate their performance, strontium cobaltite (Sr 2 Co 3 O x ​) nanoparticles were synthesized via a citrate–nitrate combustion route and incorporated during polymerization to form s-PANI/Sr 2 Co 3 O x and h-PANI/Sr 2 Co 3 O x composites. SEM and EDX analyses demonstrated that the star-like architecture enhances nanoparticle dispersion and embedding compared to the linear PANI. Dielectric and electrical measurements revealed that the s-PANI composite promotes pronounced interfacial polarization and non-Debye relaxation behavior, accompanied by enhanced permittivity and dielectric loss and reduced relaxation times. Additionally, the s-PANI/Sr 2 Co 3 O x composite exhibited a three-order-of-magnitude increase in DC conductivity (from 10 − 8 to 10⁻ 5 S/cm), surpassing the percolation threshold and outperforming linear PANI. These findings demonstrate that molecular-level branching plays a central role in influencing charge transport, highlighting star-like PANI/Sr 2 Co 3 O x composites as promising materials for antistatic coatings and electrostatic discharge protection.