Structure-property correlations in hybrid polymer-nanoparticle electrospun fibers and plasmonic control over their dichroic behavior.

Electrospinning constitutes a simple and versatile approach of fabricating polymer heterostructures composed of nanofibers. A preferred alignment of polymer crystallites stems from complex shear elongational forces and generates a strong intrinsic optical anisotropy in typical electrospun fibers of semicrystalline polymers. While it can prove useful for certain devices, this intrinsic anisotropy can be extremely detrimental for other key applications such as high-performance polymer-based lighting and solar-energy harvesting platforms. We report a dramatic reduction in the intrinsic dichroism of electrospun poly(ethylene oxide) fibers resulting from the incorporation of inorganic nanoparticles in the polymer matrix. This effect is shown to originate from a controllable randomization of the orientational ordering of the crystalline domains in the hybrid nanofibers and not merely from a reduction in crystallinity. This improved understanding of the crystalline structure-optical property correlation then leads to a better control over the intrinsic anisotropy of electrospun fibers using localized surface-plasmon enhancement effects around metallic nanoparticles.