On-surface synthesis of metal nanostructures on solid and hydrated polymer nanofibers coated with polydopamine

We introduce a bioinspired approach for synthesizing noble metal nanostructures on electrospun polymer nanofibers. Two different polymer nanofibers, poly (vinyl alcohol) and poly (ɛ-caprolactone), were prepared by electrospinning followed by coatings with polydopamine (pD) through the oxidative polymerization of dopamines. The pD coating generates a local reductive environment on the surface of the polymer nanofibers. Gold and silver nanostructures were synthesized by simply immersing the pD-coated nanofibers into an aqueous solution of metal ion precursors. While the metal ions were reduced locally on the surface of the pD layer on the poly (ɛ-caprolactone) nanofibers, resulting in large metal nanoparticles, they could easily infiltrate into the pD layer on the hydrophilic poly (vinyl alcohol) nanofibers and formed smooth polymer–metal hybrid nanostructures. This work emphasizes how the underlying polymer matrix beneath the pD layer affects the morphological differences of the metal nanostructures on the surface of the nanofibers.