Preparation of Azide functionalized nanoparticle and their use for click chemistry

Abstract

In this research, azide functionalized nanoparticles are prepared by grafting azide-end ligands on the surface of nanoparticle. Azide functionalized nanoparticles are coupled with specific designed polymers and functionalized graphene oxide by using click chemistry. In chapter 2, thermally stable core??shell gold nanoparticles (Au NPs) with highly grafted polymer shells were synthesized by combining reversible addition-fragmentation transfer (RAFT) polymerization and click chemistry of copper-catalyzed azide-alkyne cycloaddition (CuAAC). First, alkyne-terminated poly(4-benzylchloride-b-styrene) (alkyne-PSCl-b-PS) was prepared from the alkyne-terminated RAFT agent. Then, an alkyne-PSCl-b-PS chain was coupled to azide-functionalized Au NPs via the CuAAC reaction. Careful characterization using FTIR, UV??Vis, and TGA showed that PSCl-b-PS chains were successfully grafted onto the Au NP surface with high grafting density. Finally, azide groups were introduced to PSCl-b-PS chains on the Au NP surface to produce thermally stable Au NPs with crosslinkable polymer shell (Au-PSN3-b-PS 1). To demonstrate the importance of having the highly packed polymer shell on the nanoparticles, Au-PSN3-b-PS 1 particles were added into the PS and PS-b-poly(2-vinylpyridine) matrix, respectively. Consequently, it was found that Au-PSN3-b-PS 1 nanoparticles were well dispersed in the PS matrix and PS-b-P2VP matrix without any aggregation even after annealing at 220 ??C for 2 days. Our simple and powerful approach could be easily extended to design other core??shell inorganic nanoparticles. In chapter 3, CuPt nanorods with controlled size, aspect ratio and uniformity were carefully chosen and synthesized. Then, the surface of CuPt nanorods are modified by simple ligand exchange method using azide-functionalized ligands with a thiol end-group. It is well-known that the thiol group has a much stronger affinity to many metal surfaces including Au, Ag, Pt, etc than oleylamine and oleic acid....