Ni–P and TiO2 codeposition on silk textile via supercritical CO2 promoted electroless plating for flexible and wearable photocatalytic devices

Abstract

This study reported integration of Ni–P/TiO2 incorporated structure on silk textiles to produce a flexible, highly reliable, and photocatalytic composite material toward applications in functional wearable devices. Supercritical carbon dioxide (Sc–CO2) promoted electroless plating was utilized to codeposit photocatalytic TiO2 and electrically conductive Ni–P metallization layer on silk textile. Silk was chosen as the substrate for its flexibility and stretchability. Ni–P was utilized due to its high corrosion resistance, electrical conductivity, and high wear resistance. TiO2 was selected for its photocatalytic activity and acting as a reinforcement filler to fulfill requirements for applications in wearable devices. Surface morphology, composition, crystal structure, electrical resistance, corrosion resistance, adhesive test, and photocatalytic activity assessments were conducted to evaluate the practicability for wearable photocatalytic devices. With the assistance of sc–CO2, palladium (II) acetylacetonate catalyst was successfully embedded into the silk substrate at around 330 nm in depth. The coatings on the silk were confirmed to be amorphous Ni–P phase and TiO2 anatase phase. Uniform Ni–P/TiO2 composite layer with strong adherence was successfully co–deposited on the silk textile. Ni–P/TiO2 composite layer deposited with 30 g/L of TiO2 (critical concentration) in the electrolyte showed higher corrosion resistance while comparing to those of TiO2–free specimen. The Ni–P/TiO2 composite layer deposited with the critical concentration of TiO2 in the electrolyte performed the highest photocatalytic activity.