We report a facile approach to immobilizing gold nanoparticles (AuNPs) into electrospun polyethyleneimine (PEI)/polyvinyl alcohol (PVA) nanofibers for catalytic applications. In this study, electrospun PEI/PVA nanofibers with a mean diameter of 490 nm were first crosslinked with glutaraldehyde vapor to render them water stable. Then, the water-insoluble nanofibrous mats were used as nanoreactors to complex AuCl^{4 −} anions via binding with the free amine groups of PEI for subsequent formation and immobilization of AuNPs. The formed AuNPs with a diameter of 11.8 nm within the nanofibers do not significantly change the morphology of the nanofibers; while importantly the mechanical property of the fibers was greatly improved compared to the crosslinked fibers without AuNPs. Scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, energy dispersive spectroscopy, and thermogravimetric analysis were used to characterize these hybrid nanofibers. Furthermore, we show that the AuNP-containing nanofibers display an excellent catalytic activity and reusability for the transformation of 4-nitrophenol to 4-aminophenol. The present approach to fabricating AuNP-containing nanofibers may be extended for producing other nanoparticle-containing composite nanofibrous materials for various applications in catalysis, sensing, and biomedical sciences.

A new approach to immobilizing zero-valent iron nanoparticles (ZVI NPs) into electrospun polymer nanofibers with enhanced mechanical properties for environmental applications is presented. In this approach, multiwalled carbon nanotubes (MWCNTs) are mixed with polyacrylic acid (PAA)/polyvinyl alcohol (PVA) mixture polymer solution for subsequent electrospinning to form uniform nanofibers. The MWCNT-incorporated PAA/PVA nanofibers are crosslinked and then used as a nanoreactor to complex Fe(III) ions through binding with the PAA carboxyl groups for the reductive formation of ZVI NPs. The MWCNT-incorporated PAA/PVA nanofibers before and after immobilization with ZVI NPs are characterized using scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and mechanical property measurements. We show that the mechanical properties of uniform nanofibrous mats with and without ZVI NPs are significantly enhanced even with only 1.0 wt% MWCNTs incorporated. The MWCNT-reinforced PAA/PVA nanofibrous mats containing ZVI NPs (1.6 nm) display excellent capability to decolorize model dyes such as methyl blue, acridine orange, and acid fuchsine with a decoloration percentage of more than 90%. Likewise, the same nanofibrous mats are found to be able to effectively degrade trichloroethylene, a model chlorinated hydrocarbon contaminant, with a degradation efficiency approaching 93%. The MWCNT-reinforced PAA/PVA nanofibrous mats may be used for generating other functionalized nanofiber-based complex materials with enhanced mechanical properties for applications in environmental remediation, catalysis, sensing, and biomedical sciences.

Poly(ethyleneterephthalate) (PET) is a multi-purpose and widely used synthetic polymer in many industrial fields because of its remarkable advantages such as low cost, light weight, high toughness and resistance to chemicals, and high abrasion resistance. However, PET suffers from poor dyeability due to its non-polar nature, benzene ring structure as well as high crystallinity. In this study, PET fabrics were firstly treated with an alkaline solution to produce carboxylic acid functional groups on the surface of the PET fabric, and then was modified by polyelectrolyte polymer through the electrostatic layer-by-layer self-assembly technology. The polyelectrolyte multilayer-deposited PET fabric was characterized using scanning electron microscopy SEM, contact angle, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The dyeability of PET fabrics before and after surface modification was systematically investigated. It showed that the dye-uptake of the polyelectrolyte multilayer-deposited PET fabric has been enhanced compared to that of the pristine PET fabric. In addition, its dyeability is strongly dependent on the surface property of the polyelectrolyte multilayer-deposited PET fabric and the properties of dyestuffs.