Longitudinal surface plasmon resonance of gold nanoparticles as an indicator for interparticle fusions controlled by tetronics

Seed - growth (S - G) method was used to synthesize gold (Au) nanoparticles (NPs) in the presence of water soluble star polymers "tetronics" to investigate a unique photophysical behavior of Au NPs. They produced absorbance in the visible region due to longitudinal surface plasmon resonance (ISP) specifically meant for the one dimensional Au NPs such as rods, wires, and ribbons. The S - G method did not produce such morphologies rather interparticle fusions driven by the micellar assemblies of tetronic allowed Au NPs to arrange in one dimensional morphologies to generate strong ISP in the visible region. This phenomenon was mainly dependent on the pH of the medium and was only facilitated at low pH. The results showed that it was originated from the self-aggregated templating behavior of tetronic micelles under acidic reaction conditions which brought NPs together and triggered the interparticle fusions to generate one dimensional assemblies suitable for the production of LSR. The method can be applied as a sensor where photophysical response of Au NPs is pH dependent. (C) 2020 Elsevier B.V. All rights reserved.