Formation of ultrathin multilayer and hydrated gel from montmorillonite and linear polycations

Organized ceramic/polymer nanocomposites were designed from montmorillonite clay (Mont), cationic poly(ethylenimine) (PEI) or poly(dimethyldiallylammonium chloride) (PDDA) and proteins. Ordered multilayers with a controllable number of layers were prepared by alternate adsorption of delaminated montmorillonite (0.03 wt % dispersion) and polycations. Quartz crystal microbalance, X-ray diffraction, and scanning electron microscopy monitoring of the assembly have shown formation of ordered films with bilayer thickness of 3.3 nm for Mont/PEI and 3.6 nm for Mont /PDDA. Increased viscosity near the substrate was recognized at higher concentrations of Mont (1 wt %). At these and higher concentrations super hydrated (water content 99.4 wt %) solid gels of Mont and polycations were produced by mixing of their aqueous dispersions. Its open card-house structure was revealed with a scanning electron microscopy study.