Structural Tailoring of Polyaniline Synthesized by Acid‐Assisted Polymerization at Room Temperature: Insights Into Polaron Dynamics

This work presents a detailed study of the synthesis and characterization of polyaniline (PANI) using a novel acid‐assisted polymerization method with varying ammonium persulfate concentrations. Two distinct PANI samples were synthesized at room temperature, resulting in different morphologies. Scanning electron microscopy revealed a porous nanofibrillar morphology for PANI1, while PANI2 exhibited a densely packed morphology. Raman spectroscopy confirmed the presence of semiquinoid units, with characteristic bands at ~1602 and ~1500 cm −1 in both PANIs. UV–Vis spectroscopy revealed characteristic absorption bands at 259 and 428 nm, attributed to π – π * transitions and localized polarons transitions, respectively. Photoluminescence measurements identified emission bands at 2.26 and 2.18 eV, further supporting the presence of π – π * transitions. The observed energies suggest a mechanism involving the electron transfer coupled with reorganization energy, contributing to the observed spectral features. Fourier transform infrared spectroscopy confirmed the presence of key functional groups, including CH bending vibrations at ~1140 cm −1 . Given that PANI is a p‐type semiconductor with holes as the majority charge carriers, this work provides valuable insights into the structure–property relations of PANI synthesized via this novel synthesis method. These findings seem promising for the integration of PANI with carbon‐based materials, forming a composite system (electrode) for advanced energy storage applications.