We demonstrate the fabrication and characterization of optically-tunable and stimuli-responsive electrospun microfibers
endowed with liquid crystal (LC) functionality. The highly flexible LC microfibers are electrospun from a solution of 4-
pentyl-4'-cyanobiphenyl (5CB) and polylactic acid (PLA) in chloroform/acetone solvent. In the electrospinning process,
the low molecular weight 5CB phase-separates and self-assembles to form a planarly aligned nematic core within a PLA
shell. Most importantly, the orientation of LC domains and, therefore, the optical properties of the 5CB/PLA fibers can
be tuned by application of an external electric field. These properties of LC fibers may, in turn, be utilized to fabricate a
variety of photonic textiles, and ultimately may introduce an entirely new manufacturing process where weaving will
reach well beyond the roll-to-roll manufacturing envisioned for the currently emerging flexible displays printed on
flexible plastic substrates.
Recently discovered stressed liquid crystals (SLCs) are of a great interest because they provide largest phase retardation shift achievable within shortest time interval. This effect was accomplished by decoupling the speed of a liquid crystal layer from its thickness. SLCs easily switch 5 microns of the phase retardation at sub-millisecond speeds while 50 microns requires only several milliseconds. SLCs are therefore able to modulate the IR light with the frequencies higher than 10 kHz. The SLCs are polymer/liquid crystal composites; however, their electro-optic properties differ significantly from previously developed polymer dispersed liquid crystals and polymer network/stabilized liquid crystals. The applied stressed force aligns the domains, eliminating scattering and hysteresis at the same time. The phase shift is highly linear with the applied voltage, greatly simplifying the drive electronics. The SLCs pose intriguing basic scientific questions and may be used in a lot of new electro-optical applications (micro-displays, diffractive optical elements, beam steering devices).