Facile Synthesis of Thermally Stable Core-Shell Gold Nanoparticles via Photo-Cross-Linkable Polymeric Ligands

The thermally stable gold nanoparticles (Au NP) by introducing photo-cross-linkable azide groups (-Ns) into the polymeric ligands attached to the Au core was reported. The cross-linking reaction and the subsequent evaluation of thermal stability for the P(S-b-S-N3)-Au NPs were conducted in both solution and nanocomposite thin films. The cross-linked Au NPs were separated by centrifugation and dried and the thermal stability of the Au NPs in solution was tested by using dibutyl phthalate (DBP). The nanoparticles for un-cross-linked PS-Au NPs were aggregated and precipitated upon heating due to the dissociation of the Au-thiol bonds. The results indicated that the PS-N3 blocks in P(S-b-S-N3)-Au NPs could be successfully cross-linked through UV irradiation, and the dissociation of Au and thiol bond was completely suppressed due to the presence of the cross-linked PS-N3 shell.