Effect of Al(NO3)3 on suppression of the reduction of Ag ions in a poly(vinylpyrrolidone)/AgClO4 complex membrane

• Incorporation of Al(NO3)3 into poly(vinylpyrrolidone)/AgClO4 complex.
• The use of Al(NO3)3 to suppress the reduction of Ag+ ions originating from the AgClO4 salt.
• Formation of silver nanoparticles in PVP/AgClO4 film in the absence of Al(NO3)3.

Our previous study showed that the incorporation of Al(NO3)3 into a polymer/AgBF4 complex could enhance the long-term stability of film capable of showing the antibacterial effect and olefin/paraffin separation, because the Ag+ ions were not easily converted into Ag nanoparticles. In this study, the effect of Al(NO3)3 on the suppression of the reduction of the Ag+ ions originating from the AgClO4 in the polymer was investigated, because AgClO4 is more cost effective than AgBF4. As a result, the use of Al(NO3)3 was found to suppress the reduction of Ag+ ions originating from the AgClO4 salt, whereby the stability of the Ag+ ions was largely enhanced even though it is well known that these ions are readily reduced to Ag nanoparticles. Actually, Ag nanoparticles were shown to easily form from the poly(vinylpyrrolidone)/AgClO4 complex in the absence of Al(NO3)3, as confirmed by transmission electron microscopy (TEM) and UV–vis spectra.