Polyaniline/Carboxymethyl Cellulose (PANI/CMC) Conductive Polymer Composites: A Review of Synthesis, Properties, and Applications

Intrinsically conducting polymers (ICPs), most notably polyaniline (PANI), have fundamentally bridged the gap between conventional insulating plastics and metallic conductors. However, the commercial and industrial integration of PANI remains hindered by its rigid aromatic backbone, which results in poor organic solubility and inherent mechanical brittleness. This review critically evaluates the strategic development of PANI-based composites utilizing carboxymethyl cellulose (CMC)—a sustainable, anionic biopolymer—as a stabilizing matrix and molecular template. We provide a detailed examination of the in situ oxidative polymerization process, elucidating how the carboxylate and hydroxyl functional groups of CMC facilitate a synergistic triple-force interaction involving electrostatic anchoring, multi-point hydrogen bonding, and directed π-π stacking. This molecular synergy is shown to fundamentally alter the physicochemical landscape of the polymer, resulting in superior water dispersibility, enhanced thermal stability, and a tran-sition to a flexible, film-forming morphology via the molecular lubricant effect. Furthermore, this review assesses the functional performance of PANI/CMC hybrids across high-impact tech-nological frontiers: in electrochemical energy storage, where CMC acts as a structural buffer to enhance capacitance retention; in room-temperature gas sensing for VOC detection; and in environmental remediation, where the dual-mode binding sites achieve superior sequestration of organic dyes and heavy metal ions (Pb2+, Cd2+, Cr6+). These characteristics underscore the potential of PANI/CMC composites as a cornerstone for the next generation of sustainable, high-performance conductive materials in green electronics and environmental engineering.