Gold Nanospheres Assembled on Hydrogel Colloids Display a Wide Range of Thermoreversible Changes in Optical Bandwidth for Various Plasmonic-Based Color Switches

Abstract

An approach is presented that permits wide and reversible control of the optical bandwidth of spherical gold nanoparticles assembled on thermoreversible hydrogel colloids for various plasmonic-based thermochromisms. Temperature-dependent swelling and shrinking behaviors of the hydrogel colloids in aqueous systems manipulated assembly structures and optical signals of gold nanoparticles in the hybrid colloids. The optical bandwidths of the hybrid colloids increased with temperature, and thermoreversible bandwidth variations of the hybrid colloids were increased with the diameter of gold nanoparticles (from 15 to 51 nm). These hybrid colloids exhibited multiple colors switching during temperature changes (maximum four colors: wine <-> violet <-> dark blue <-> faint blue). For the hybrid colloids showing a small bandwidth variation, another method was introduced to display different color switching.