Comparison of Two Synthesis Routes to Obtain Gold Nanoparticles in Polyimide

Gold nanoparticle containing polymer materials find applications in catalysis, facilitated transport, sensing, and separations. In this study, two routes to obtain stable gold nanoparticles in a polymer matrix, namely, in situ chemical reduction of a gold salt and the use of preformed poly(vinylpyrrolidone) protected gold nanoparticles, were followed to prepare gold containing polyimide hybrid membranes. The influence of the synthesis method on the nanoparticle size, dispersion, and surface plasmon behavior was investigated by transmission electron microscopy, UV–vis spectroscopy, and diffuse reflectance spectroscopy. Significant differences were found concerning the dispersion and aggregation of the nanoparticles. The influence of the synthesis method on the membrane structure and performance was also studied by scanning electron microscopy and in filtrations of dye solutions in ethanol and isopropanol. The filtrations were repeated while the gold nanoparticles were plasmonically heated by a green Argon ion laser beam, resulting in localized heating of the membrane and increased fluxes.