Synergistic enhancement of conductivity in natural rubber – PEDOT:PSS composites using glycerol, polyethylene glycol, and CNTs

This study presents the preparation and analysis of conductive composite films based on natural rubber (NR) and PEDOT:PSS. The percolation fitted model was applied to evaluate the electrical behavior of the composites, resulting in a percolation threshold at a PEDOT:PSS volume fraction of 0.67. SEM and IR analyses confirmed that continuous conductive networks were not formed below this threshold. To enhance conductivity in the sub-threshold regime, glycerol and polyethylene glycol (PEG) were added as non-conductive additives, resulting in up to two orders improvement in conductivity compared to the additive-free system. Further enhancement was achieved through the incorporation of glycerol and carbon nanotubes (CNTs), increasing conductivity to 1.01 × 10⁻² S/m at the volume fraction PEDOT:PSS of 0.2 below the percolation threshold. SEM and IR analyses indicated the improvement in dispersion and interfacial interaction. These findings highlight additive-assisted strategies as effective in lowering the percolation threshold and offer a scalable route for developing flexible, low-cost conductive polymer composites.