Preparation of PVP–PVA–exfoliated graphite cross-linked composite hydrogels for the incorporation of small tin nanoparticles

The direct exfoliation of graphite was achieved in water using water-soluble poly(vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA). Prepared wrapped graphene dispersion was employed for the synthesis of chemically cross-linked PVP/PVA/exfoliated graphite (G) composite hydrogels. The swelling behaviour of these hydrogels was studied in aqueous solution of stannous chloride, followed by treatment in a bath of sodium borohydride (NaBH4). The previous PVP/PVA–graphene aqueous dispersion was analyzed by UV–Visible and Raman spectroscopy. The morphology of the composite hydrogels was observed by field-emission scanning electron microscopy (FE-SEM). The successive modifications of the composite hydrogels, in particular the incorporation of tin nanoparticles (SnNPs) were monitored by (FT-IR) Fourier transform-infrared spectroscopy. The size and shape of the incorporated SnNPs were controlled by transmission electron microscopy (TEM).