Optimization of Oxidant Type, Acid Dopant, and Molar Ratio for Controlling the Structural and Electrical Properties of Polyaniline

Abstract

polyaniline is one of the most attractive intrinsically conducting polymers due to its easy synthesis, environmental stability, and tunable electrical properties. In this work, PANI was chemically synthesized by oxidative polymerization in acidic medium by varying the oxidant type (Ferric chloride or Potassium permanganate), acid dopant (Hydrochloric acid or Sulfuric acid), and aniline/oxidant molar ratio (1:1 and 1:2). The obtained samples were characterized by FTIR, XRD, UV–Vis, TGA, and four-point probe conductivity measurements. FTIR confirmed the successful formation of PANI, while XRD revealed a semi-crystalline structure with crystallite sizes ranging from 4.733 to 6.514 nm. Electrical conductivity strongly depended on synthesis conditions, reaching a maximum value of 4.739 S·cm⁻¹. UV–Vis analysis confirmed the formation of polaronic charge carriers, and TGA demonstrated good thermal stability with degradation temperatures above 500 °C. These results highlight the key role of synthesis parameters in controlling the structural organization and electrical performance of PANI.