Preparation of Exfoliated Ag-Laponite Nanocomposites Through a Freeze-Drying of Laponite Sols

Colloidal Ag and Au nanoparticles have been intensively studied due to their potential and real applications varying from optics and catalysis to biomedicine.1-3 Many methods exist for the synthesis of Ag and Au nanoparticles, but most processes result in low nanoparticle concentrations due to aggregation into large particles.4.5 Surfactants, thiols or clays as capping agents or stabilizing reagents have been used effectively to prevent the growth and aggregation of nano-particles. In particular, high concentrations of Ag colloidal sol have been obtained using synthetic layered clay, laponite as a steric barrier to prevent aggregation of Ag nanoparticles.6 The use of clay for high concentrations of noble metal nanoparticles generates nanoparticle/clay composites that are believed to be important materials with a large variety of applications in functionalized ceramics, adsorbents, ion ex