Poly(3-hexylthiophene)-stat-poly(3-dodecylselenophenes): Conjugated Statistical Copolymers and Their Gels

The molecular weight of conjugated polymers plays an important role in n polymer self-assembly, which has a significant influence on their application in electronics. In this work, we report the self-assembly behavior of poly(3-hexylthiophene)-stat-poly(3-dodecylselenophenes) as both thin films and organogels at low, medium, and high degrees of polymerization. Different self-assembly behaviors are observed in pristine copolymer films, annealed copolymer films, and copolymer gels. We found that through cycle-doping, a process by which the sample is gelled and repetitively doped by solution, conjugated statistical copolymer gels have greater conductivities compared to thin films of the same polymers and maintain high conductivities after seven cycles of doping. Statistical copolymer gels at medium and high degrees of polymerization show the greatest conductivity, which is likely due to their unique morphology from that of the low degree of polymerization. Grazing incident wide-angle X-ray scattering suggests an inter charge transfer doping mechanism takes place between the polymer and dopant.