Preparation of Conductive Gold Nanowires in Confined Environment of Gold-Filled Polymer Nanotubes

Mitschang F, Langner M, Vieker H, Beyer A, Greiner A. Preparation of Conductive Gold Nanowires in Confined Environment of Gold-Filled Polymer Nanotubes. Macromolecular Rapid Communications. 2015;36(3):304-310.Continuous conductive gold nanofibers are prepared via the tubes by fiber templates process. First, poly(l-lactide) (PLLA)-stabilized gold nanoparticles (AuNP) with over 60 wt% gold are synthesized and characterized, including gel permeation chromatography coupled with a diode array detector. Subsequent electrospinning of these AuNP with template PLLA results in composite nanofibers featuring a high gold content of 57 wt%. Highly homogeneous gold nanowires are obtained after chemical vapor deposition of 345 nm of poly(p-xylylene) (PPX) onto the composite fibers followed by pyrolysis of the polymers at 1050 degrees C. The corresponding heat-induced transition from continuous gold-loaded polymer tubes to smooth gold nanofibers is studied by transmission electron microscopy and helium ion microscopy using both secondary electrons and Rutherford backscattered ions

Transition-Metal-Functionalized PAMAM Dendrimers Encapsulated in PPX Tubes as Reusable Catalysts

Composite nanofibers of polyurethane and catalytically active Pd- or Cu-functionalized poly­(amido amine) dendrimers were electrospun and subsequently coated with poly­(<i>p</i>-xylylene) by the chemical vapor deposition. After removal of the inner polyurethane template matrix, the dendrimers remained encapsulated inside the confinement and the leaching behavior of the caged dendritic catalysts was studied. The tube system was successfully used as a readily reusable tea bag type catalyst for Suzuki–Miyaura couplings and alkyne/azide click reactions