WO3 Nanowires Enhance Molecular Alignment and Optical Anisotropy in Electrospun Nanocomposite Fibers: Implications for Hybrid Light-Emitting Systems

The molecular orientation in polymer fibers is investigated for the purpose of enhancing their optical properties through nanoscale control by nanowires mixed in electrospun solutions. A prototypical system, consisting of a conjugated polymer blended with polyvinylpyrrolidone, mixed with WO3 nanowires, is analyzed. A critical strain rate of the electrospinning jet is determined by theoretical modeling at which point the polymer network undergoes a stretch transition in the liber direction, resulting in a high molecular orientation that is partially retained after solidification. Nearing a nanowire boundary, local adsorption of the polymer and hydrodynamic drag further enhance the molecular orientation. These theoretical predictions are supported by polarized scanning near-field optical microscopy experiments, where the dichroic ratio of the light transmitted by the liber provides evidence of increased orientation nearby nanowires. The addition of nanowires to enhance molecular alignment in polymer libers might consequently enhance properties such as photoluminescence quantum yield, polarized emission, and tailored energy migration, exploitable in light-emitting photonic and optoelectronic devices and for sensing applications.

Automated summary

The molecular orientation in polymer fibers can be enhanced by mixing nanowires, resulting in improved optical properties. Experimental results showed that the molecular orientation was significantly increased near the nanowire boundaries. This method has potential applications in improving the performance of optical devices and sensors.