Highly Aligned Electrospun Polymer Fibers Produced Using a Corrugated Static Collector

Fiber alignment via electrospinning is a challenging process that requires complex optimization because of the synergistic contribution of the solution, processing, and environmental parameters. Much of the work has focused on the design of collectors that enable fiber alignment, in contrast to that of the stationary, flat collector where randomly oriented fibers are deposited. However, in most cases, the proposed collectors have either movable parts or complicated configurations. The present study focuses on a simplified design concept involving the use of a corrugated metallic collector in the production of highly aligned electrospun fibers based on three polymer systems exhibiting different physicochemical characteristics: Polyvinylpyrrolidone (PVP) (insulating), poly(3-hexylthiophene-2,5-diyl) (P3HT)-rich polymer blend (semiconducting), and poly(4-vinylpyridine-co-butyl methacrylate) (P4VPBuMA) (polyelectrolyte). The electric field profile developed in the presence of the corrugated collector was simulated by means of finite element analysis and compared to that of the conventional flat collector. Most importantly, electrospun meshes with an exceptionally high degree of alignment (up to 95%) after a prolonged electrospinning time were produced in all cases, thus demonstrating the effectiveness of this simple collector design approach on the production of highly oriented electrospun polymer fibers of various chemical compositions. Electro-optical characterization of the P3HT systems shows that oriented fibers exhibit identical optical properties to fibers with random orientation, indicating that the molecular conformation and structural state of the fibers is not affected by the alignment process during electrospinning. On the other hand, aligned fibers exhibit superior electrical properties, as evidenced by the suppression of hysteresis and an increase of photoconductance by up to 2.5 times compared to the respective characteristics of randomly oriented fibers due to an alignment-induced reduction of capacitive parasitic effects.