Incorporation of an elastomer into poly(3‐hexylthiophene) bilayers: towards a flexible conductive polymer film

Flexible, wconductive polymer films are crucial for next‐generation wearable electronics, soft robotics and biomedical devices. Traditional conducting polymers like poly(3‐hexylthiophene) (P3HT) are rigid due to strong π–π interactions. We investigated mixtures of polydimethylsiloxane (PDMS), a highly flexible elastomer, and P3HT bilayers to understand their interaction and characterize the resulting nanoscale organization and electronic properties. Composite P3HT:PDMS films were fabricated at the air–water interface, allowing precise control over nanoscale morphology. Characterization revealed complete phase separation with crystalline P3HT nanofibers in a PDMS matrix. Sequential doping with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F 4 TCNQ) led to a 4%–5% contraction in the π–π stacking distance, indicating polaron formation while maintaining phase separation. Electronic conductivity measurements revealed a percolation threshold at 30% PDMS content. Films with 10% PDMS achieved conductivities around 0.1 S cm –1 , comparable to pure P3HT. Multilayer films (five layers) reached conductivities up to 1.5 S cm –1 , showing minimal adverse impact on charge transport.