Isoindigo-Based Binary Polymer Blends for Solution-Processing of Semiconducting Nanofiber Networks

Molecular self-assembly in isoindigo-based binary polymer blends as a novel platform for facile and robust formation of semiconducting nanofibers is studied. We designed structurally complementary polymers to process all-semiconducting nanocomposites. The selection of the tie-polymer for nucleation and nanofiber formation was probed by tuning crystallinity via side chain engineering. Morphology studies revealed that the crystallinity and the scale-like morphology of the tie-polymer play a crucial role in making long and well stacked nanofiber networks. The optimized blends could be solution-processed into nanotailored semiconducting thin films with no postprocessing steps required. The nanofiber formation in thin films further led to lowered elastic moduli and glass transition but higher crack-on-set strain as well as excellent charge transport properties. The formed nanofibers could also be aligned via a blade-directed shearing method to fabricate organic field-effect transistor devices. Our blending strategy shows to be a promising facile route for processing flexible and stretchable organic semiconducting thin films.