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.