Photo-induced design of reflective metallized gold@polymer coatings with tuned architecture

Abstract

This paper presents an efficient, eco-friendly, low cost and totally photo-induced approach to obtain new gold metallized coatings with highly reflective feature. Depending on gold precursor used and experimental conditions, the metal nanoparticles are distributed full depth or concentrated at the surface of the polymer matrix. The spatial organization and distribution of gold nanoparticles (AuNPs) is obtained through a perfect tuning of two concurrent processes, i.e. photo-polymerization of the binder and photo-reduction of the gold precursor to Au(0) nanoparticles, the balance of which is influenced depthwise, by internal filter effects associated to the absorption of gold particles or precursor. Two distinct classes of architectures were obtained. One of them was a bi-layered coating, i.e. a polymer rich sub-layer with a metal cover layer with a sharp delimitation between them; as for itself, the second type of metal@polymer coating exhibited a clear depthwise gradient of Au NPs concentration with a quasi-compact metal layer at the air surface. The mechanisms underlying these two types of architectures are discussed.The metal@polymer coatings developed with this innovative approach are full of promise in many fields of application such as large scale functionalized surfaces, adaptive optical devices (plasmonic and mirror), flexible conductive surfaces and aesthetics.