Design of responsive fluorescence-switching hybrid nanocomposite through selective layering of nanoparticles

Abstract

Hybrid nanocomposite, a material where inorganic nanoparticles are introduced into a polymer matrix, has been received tremendous attentions due to its novel properties based on the synergistic effect. Herein, we report the solvent-sensitive fluorescence-switching hybrid microsphere through controlling the location of nanoparticles (NPs) in the block-copolymer (BCP) particles. Polystyrene-grafted gold nanoparticles (Au@PS) and quantum dots (QD) were arranged in different layers inside the onion-shaped polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) particles during co-assembly process. As the luminous QDs and light-absorbing Au@PS are arranged in distinctive polymer layers, the interparticle distance is too close to express effulgence of QD. However, poly(4-vinyl pyridine) is swelled in ethanol to increase the distance between dissimilar NPs and enhance luminescence properties. Fluorescence-switching occurs even when particles are made of polymer matrices with different molecular weights or dispersed in water-ethanol mixtures with various composition ratios. The phenomenon of the hybrid particles was quantified by fitting the relationship between the energy transfer efficiency and the distance between heterogeneous NPs into a Nanometal Surface Energy Transfer (NSET) model.