One‐Pot Photochemical Synthesis of Gold Nanoplates Using Nonionic Diblock Copolymers and their Surface Functionalization

Abstract

Two‐dimensional gold nanoplates (AuNPLs) have been of significant interest because they are ideal substrates for surface modification and surface‐enhanced Raman spectroscopy. Conventionally, AuNPLs are synthesized using a seed‐mediated growth method employing cetyltrimethylammonium bromide (CTAB) as a shape‐directing agent (SDA). The CTAB‐based method, however, suffers from cumbersome multistep growth, unsuccessful surface modification, and high cytotoxicity. Therefore, the development of facile and CTAB‐free synthesis of AuNPLs is required to address these challenges. Herein, we present a one‐pot photochemical synthesis of AuNPLs with an average diameter of 1.5 μm using a nonionic diblock copolymer, Brij‐58, as both an SDA and a reductant. The growth of AuNPLs is thermodynamically and kinetically investigated by controlling the reactant concentrations, reaction temperatures, and head‐to‐tail ratios of Brij polymers. Furthermore, the synthesis is conducted in the presence of seed particles, resulting in a larger diversity of structures. Notably, the obtained AuNPLs are successively conjugated with thiolated DNA, thus demonstrating the surface potential of the AuNPLs as a reversible assembly platform for bioanalytical applications.