Spatially selective modification of gold nanorods

In this contribution, we present the new approach for plasmon assisted grafting of anisotropic gold nanorods (AuNRs) with spatial selectivity, which was used for creation of nanoparticles with amphiphilic surface. The surface modification was carried out in two stages with implementation of: (I) the plasmon-activated iodonium salt (IS), and (II) the aryl diazonium salt (ADT). The plasmon assisted activation of IS was performed under the illumination of AuNRs with wavelength corresponded to the longitudinal plasmon resonance of AuNRs and resulted in grafting of organic moieties (Ar-(CF3)2) to AuNRs edges. The AuNRs lateral sides remains ungrafted and were further decorated with ADT-COOH. As result of varying substituents in the chemical structures of iodonium and diazonium salts the amphiphilic NPs with spatially divided hydrophobic (grafted to AuNRs edges) and hydrophilic (grafted to AuNRs lateral sides) chemical groups were obtained. Corresponded UV-Vis and Raman measurements confirm the success of AuNRs chemical grafting. As result, the AuNRs with spatially separated chemical moieties were created in very simple way, primarily in solution and without the need of sophisticated technique of NPs mobilization or their surface screening.