Polyaniline–Cu hybrid conductive composites with exceptional oxidation stability

Copper is widely used in electronic applications, however, its rapid oxidation under ambient and corrosive environments significantly limits long-term performance. Here, we report highly stable polyaniline–copper (PANI–Cu) hybrid composites achieved by controlling the redox state of the PANI matrix. Three composites (PANI EB–Cu, PANI EB/LB–Cu, and PANI LB–Cu) were synthesized via a chemical reduction process. Increasing the reduction degree of PANI enhances the density of electron-donating amine groups, promoting strong coordination with copper and improving particle dispersion. As a result, PANI LB–Cu exhibits a higher work function (4.94 eV) and superior resistance to oxidation. After thermal sintering, it exhibits an electrical conductivity of 1.2 × 104 S cm-1, which remains stable over 4728 h under ambient conditions. In a seawater immersion test, PANI LB–Cu maintains its conductivity even after 560 h with minimal degradation, whereas conventional copper rapidly deteriorates. X-ray photoelectron spectroscopy reveals that the PANI matrix undergoes preferential oxidation, acting as a sacrificial layer that protects the copper from corrosion. These findings demonstrate that redox-state engineering of conducting polymers is an effective strategy for developing highly stable metal–polymer hybrid conductors for use in harsh environments.