Preparation and Performance Study of Hydroxypropyl Methylcellulose/Polyaniline Composite Conductive Films

This study developed a highly conductive polyaniline (PANI) composite film. The synthesis involved first reacting epichlorohydrin (ECIP) with hydroxyl groups on hydroxypropyl methylcellulose (HMPC), creating reactive sites. Subsequently, aniline (An) was grafted onto the HMPC backbone via ECIP bridging, followed by oxidative polymerization to yield polyaniline grafted hydroxypropyl methylcellulose (PANI-g-HMPC). Further internal doping of the PANI was achieved by grafting 3-chloro-2-hydroxypropyltrimethylammonium chloride (QA) onto PANI-g-HMPC. This approach effectively overcame critical defects of conventional PANI, including poor stability and film-forming ability, low film strength, poor PANI dispersion in composite films, and low conductivity etc. Furthermore, this work introduces, for the first time, the use of glutaraldehyde (GA) to address the hygroscopicity of PANI-g-QA/HMPC film by aldol reaction to consume hydroxyl groups of HMPC, successfully preparing a hydrophobic PANI-g-QA/HMPC/GA composite film. The optimized composite film exhibits a high conductivity of 1.582 S/cm and a tensile strength of 120 MPa, approximately double that of the typical in situ polymerized PANI composite films. The resulting PANI-g-QA/HMPC/GA composite film holds broad application prospects in fields such as conductive films, conductive coatings, conductive paste et al.