Gilding of Polymers from Thin Sorption Layers of Solutions by a Combination of Photochemical and Chemical Processes

This study proposes a novel method for depositing highly conductive gold films onto polymer surfaces. Gold is widely used in electronics, optics, and catalysis due to its exceptional electrical conductivity, corrosion resistance, and ability to reflect infrared radiation. Currently, the main methods for gold deposition on dielectrics are expensive vacuum sputtering or multi-stage chemical plating, which often require toxic reagents and preliminary substrate metallization. Photochemical metallization serves as a promising and eco-friendly alternative, allowing for the direct reduction of gold ions under light radiation directly on polymer surfaces. To achieve direct gold plating on polypropylene, the surface is initially hydrophilized by mechanical treatment and etching, and then activated in a copper chloride solution. A sorption layer of gold (III) chloride (AuCl۳) and ascorbic acid is applied to the prepared plate, where intense light radiation (۸۰۰-۱,۱۰۰ W/m²) triggers the simultaneous photochemical and chemical reduction of gold ions. Using thin sorption layers of AuCl۳ and ascorbic acid significantly increases light exposure efficiency, creating crystallization centers via the photonic reduction of gold ions. Combining photochemical reduction with ascorbic acid eliminates "shadow effects" and voids by filling intercrystallite spaces, ensuring the formation of a continuous, conductive layer up to ۱۰ micrometers thick. Experimental investigations clearly show that optimal reagent concentrations (۲۰-۴۰ g/L AuCl۳ and ۳۰-۴۰ g/L ascorbic acid) guarantee high adhesion and complete gold utilization without washing losses. Process control, along with structural and phase composition analysis of the coatings, was performed using scanning electron microscopy and energy-dispersive X-ray spectroscopy.

کلیدواژه ها:

Polymer ، Gilding ، Gold (III) chloride ، Ascorbic acid ، metallization