Electrospun Nanoparticle-Nanofiber Composites via a One-Step Synthesis

A facile approach to synthesize and incorporate metal nanoparticles (NPs) into electrospun polymer nanofibers (NFs) wherein the electrospinning polymer acts as both a reducing agent for the metal salt precursor, as well as a protecting and templating agent for the ensuing NPs, is reported. Such a true one-step process at ambient conditions and free of organic solvents is demonstrated using a system comprising AgNO3 and poly(ethylene oxide) (PEO) at electrospinnable molecular weights of 600, 1000, or 2000 kDa. The PEO transforms Ag+ into AgNPs, a phenomenon that has not been previously possible at PEO molecular weights less than 20 kDa without the addition of a separate reducing agent and stabilizer or the application of heat. Results from X-ray photoelectron spectroscopy and UV-Vis absorption spectrophotometry analyses support the formation of pseudocrown ethers in high molecular weight PEO as the mechanism in the development of NPs. The AgNPs reduce fiber diameter and enhance fiber quality (reduced beading) due to increase electrical conductivity. Interestingly, several of the NFs exhibit AgNP-localized nanochain formation and protrusion from the NF surface that can be attributed to the combined effect of applied electrical field on the polymer and difference between the electrical conductivity and polarizability of the polymer and metal NPs.