Highly stretchable coaxial P3HT electrospun fibers with enhanced reversibility

Conjugated polymers have potential applications in many areas, including stretchable photovoltaic, wearable sensors, electronic skin, and flexible displays. The polymer must maintain electronic properties with mechanical deformation for these applications, particularly repetitive mechanical loading and unloading. Achieving such is a significant challenge, as the performance of many systems deteriorates under stretched conditions. Here, we report the fabrication of highly stretchable coaxial fibers consisting of semiconducting poly(3-hexylthiophene) (P3HT), and butyl rubber (BR) obtained using an electrospinning technique. Because of the presence of P3HT in the shell, these fibers could be easily doped using F4TCNQ. For these highly stretchable fibers, the electrical conductivity for the doped fiber did not change significantly up to 400% strain. Further, the conductivity is maintained for this applied strain under cyclic loading, showing excellent mechanical reversibility and electrical durability of the fibers. Moreover, the presence of P3HT at the shell facilitates the direct doping of the fiber without any post-treatment of the fiber mat. Besides, other polymers were successfully used as a core in the coaxial fibers, demonstrating the general applicability of our spinning approach. Highly stretchable and reversible electrospun fibers with a fracture strain of approximately 1000% were developed. The doped fibers maintain electrical conductivity up to 400% strain.