One-dimensional hairy CNT/polymer/Au nanocomposites via ligating with amphiphilic crosslinkable block copolymers

Abstract

The ability to create one-dimensional (1D) nanomaterials with precisely controlled dimensions and compositions enable investigation into the relationship between their 1D structure and intriguing properties. However, it remains challenging to develop a general approach for producing robust 1D nanomaterials of different aspect ratios. Here, we report the crafting of hairy 1D carbon nanotube (CNT)/polymer/Au nanocomposites with tunable length by capitalizing on rationally-designed amphiphilic, crosslinkable triblock copolymers as nanoreactors. Specifically, poly(ethylene glycol)-block-poly(acrylic acid)-block-poly(4-vinylbenzylazide-co-styrene) triblock copolymer (denoted PEG-b-PAA-b-(PVBA-co-PS)) with a well-controlled molecular weight of each block is synthesized and exploited to ligate on CNT via strong π-π stacking and hydrophobic interactions. Subsequent crosslinking of PVBA blocks via UV irradiation, followed by the introduction of Au precursors, leads to the formation of PEG-capped 1D CNT/crosslinked PVBA-co-PS/Au (i.e., core/shell 1/shell 2) nanocomposites. In stark contrast to conventional methods for yielding CNT-based 1D nanomaterials, our amphiphilic crosslinkable block copolymer nanoreactor strategy circumvents the alteration and/or destruction of intrinsic properties of CNT. The thickness of the outer Au shell anchored on CNT is dictated by the length of PAA blocks. Furthermore, the plasmonic property of 1D CNT/crosslinked PVBA-co-PS/Au nanocomposites can be tailored by selective separation via centrifugation. The resulting hydrophilic 1D CNT/crosslinked PVBA-co-PS/Au nanocomposite demonstrates improved catalytic activity over the Au nanoparticle counterpart. This strategy can be readily extended to construct other appealing low-dimensional hybrid nanomaterials of interest for diverse applications including sensors, catalysis, energy conversion and storage, etc.