Preparation of Ultrathin Nanocomposite Films from Exfoliated Aluminosilicate/Coumarin Dye Complexes and Cationic Polyelectrolytes by Layer-by-Layer Deposition

Abstract

ABSTRACTMultilayer nanocomposite films have been prepared from exfoliated aluminosilicate/coumarin dye complex through layer-by-layer self-assembly using cationic polyelectrolytes. Coumarin dye molecules were intercalated into the layered aluminosilicate by an ion exchange reaction. Particles of the hectorite/dye complex were delaminated by extensive shaking and sonication of their water suspension into 2∼3 nm-thin silicate layers with molecules of the dye adsorbed on their surface. Atomic force microscopy and transmission electron microscopy data are in agreement with such a model. Ultrathin multilayered films were prepared using layer-by-layer self-assembly from the aluminosilicate platelets and a cationic polyelectrolyte polydiallyldimethylammonium chloride (PDAC). Linear build-up of the films up to 20 cycles was demonstrated and investigated using absorption spectroscopy and spectrofluorometer. The resulting transparent films have exhibited strong characteristic blue-green fluorescence due to coumarin dye molecules adhered to the exfoliated hectorite platelets.