Abstract

Plasmonic nanoparticle assemblies have been exhibiting unique collective properties absent in their individual counterparts. However, it is an important challenge to manipulate those properties due to the difficulty in controlling the arrangement and distance between plasmonic nanoparticles. Herein, we propose an alternative strategy for manipulating the distance between gold nanoparticles on the plasmonic vesicles to afford tunable collective properties by changing temperature. To reach this goal, a thermally responsive vesicle is self-assembled from an azobenzene-terminated homopolymer, poly(2-(2-ethoxyethoxy)ethyl acrylate) (Azo-PEEA). Gold nanoparticles are then decorated on its membrane to afford plasmonic vesicle, which can be grouped and fused into larger plasmonic vesicle when heated. Consequently, the gold nanoparticles are getting closer, creating local hot spots at the gap between adjacent gold nanoparticles, leading to the red shift of local surface plasmon resonance (LSPR) peaks and better surface-enhanced Raman scattering (SERS). Besides, the structure and the collective optical properties of the plasmonic vesicles can be reserved at various conditions, e.g., different pH values, high salt concentration and relatively high temperature once they are heated up to 35 ℃.

文章链接： Nanoscale 2018, 10, 17354-17361.