Fabrication of polyurushiol/Ag composite porous films using an in situ photoreduction method

In this work, polyurushiol (PUS) was synthesized through a Friedel-Crafts reaction using bronsted acid as a catalyst. The product was then utilized in the fabrication of honeycomb porous films by breath figures (BFs). The PUS porous films were subsequently exposed to a high pressure mercury lamp for several seconds (5-30 s). An AgNO3 solution was then dripped onto the surface of films to form PUS/Ag composite porous films through the in situ photoreduction method, avoiding the use of harmful reducing agents. Key preparation factors, including solvent type, UV irradiation time and AgNO3 concentration, were systematically investigated. The composite films were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Ag particles (approximate size of 50 nm) were formed on the surface of PUS porous films when water was used as a solvent. In addition, increased AgNO3 concentration or UV irradiation time facilitated a change in the conductivity state of PUS/Ag porous films from insulator to semiconductor. The as-prepared PUS/Ag composite porous films provided excellent electronic properties and thus provided significant potential for future application in various fields.