Facile and controllable incorporation of gold nanoparticles within one-dimensional self-assemblies of hyperbranched polymers

Abstract

Using a mono-pyrene terminated hyperbranched polyglycidol (mPTHP) as a building block, one-dimensional (1D) mPTHP and mPTHP/gold nanoparticle (Au NP) nanostructures are fabricated in the presence of HAuCl4. By simply mixing mPTHP and different concentrations of aqueous HAuCl4 solution at room temperature, mPTHP nanofibers and nanotubes are obtained through Au(III) ion induced self-assembly processes. Upon elevating the reaction temperature from room temperature to 60 °C, Au NPs are in situ generated within 1D mPTHP assemblies via an analogous “polyol process”, forming mPTHP/Au NP hybrid nanofibers and nanotubes. Careful control of the HAuCl4 concentration enables in situ generated Au NPs to be either distributed along the center-line of nanofibers or symmetrically aligned into a double-line along the nanofibers and the inner surface of nanotubes. Further investigation reveals that the involvement of a small amount of NaBr in the reaction system of mPTHP and different amounts of HAuCl4 results in the formation of pseudo-nanotubes decorated with double-lined Au NP chains along their inner surfaces. Moreover, the size of Au NPs can be effectively tuned in terms of HAuCl4 concentration. All 1D mPTHP and mPTHP/Au NP nanostructures described in our current work are achieved through one-pot aqueous reactions in the absence of any additional reducing agents, surfactants and organic solvents, so that they are facile, green and low-cost strategies. To the best of our knowledge, this is the first example to synthesize 1D hyperbranched polymer/metal NP hybrid nanostructures with controllable spatial distribution of NPs using such a facile and green protocol.