Au Nanoparticles As Nucleation Seeds for Carboxylic Acid Nanorods

This presentation describes the synthesis, characterization, and immobilization of oleylamine capped Au nanoparticles (OA-AuNPs) as well as their capability as nucleation seeds. The NPs were synthesized by one phase reaction in toluene, in which OA serves as a reducing as well as a stabilizing agent to control the particle size. The NPs were characterized by AFM, TEM, XRD, and TGA. The OA-AuNPs were used to induce nanorod formation of carboxylic acids with different carbon chain lengths. AFM images show nanorods of carboxylic acids with dimensions consistent with the C-form crystal structure nucleated near the NPs. The cross sectional dimension of the nanorods is as small as one crystalline unit cell. Unlike previous studies of carboxyl-terminated nanoparticles, some nanorods are near but not directly attached to methyl-terminated OA-AuNPs. It is hypothesized that the extremely narrow nanorods are formed due constraints imposed by the highly curved NP surface. This work contributes to the understanding of nanoconfinement effect on crystallization. It offers a new method to create hybrid nanostructures that employs the dual functionalities of the inorganic nanoparticle and organic nanorod.