Functionalized electrospun nanofibers integrated with Ag/Au nanoparticles as a platform for enhanced nonlinearity

Abstract

The potential openings promised by nanotechnology for enabling advances in optics are astounding. Electrospinning is a well established technique in which polymers/co-polymers are blended together to produce novel polymeric materials of desired properties to suit diverse domains of applications in the arena of optics, agriculture, energy, biotechnology. The addition of nanoscale fillers to surface and interior of electrospun nanofibers is an efficient method for the modification of physical properties as well as the performance of polymer matrix. Assembling and confining silver (Ag)/gold (Au) nanoparticles in nanofibers whose size is of the order of wavelength of light can efficiently trap and scatter leading to enhanced light matter interaction. In the present study we observed the nonlinear absorption of these Ag/Au functionalized Casein (CAN)/Polyvinyl Alcohol (PVA) electrospun nanofibers and compared it with that of Au/Ag nanoparticles dispersed in polymer solution. UV–Vis absorption studies and morphological analysis of the prepared materials confirms the incorporation of Au/Ag nanoparticles into the polymer matrix. Open aperture Z-scan measurements at 532 nm, 5 ns laser pulses shows that nanofibers with Au/Ag nanoparticles exhibited higher nonlinear absorption coefficient than its nanocomposite solution. This enhancement in two photon absorption is correlated with the morphology of composite nanofibers and electric field enhancement of nanoparticles into the polymer matrix. Optical limiting performance of the prepared nanocomposites and composite nanofibers offer a better result than the bare polymer due to the two photon absorption of the Au/Ag nanoparticles in nonresonant/resonant regime, thus making it suitable for optical limiting applications.