Interlayer charge conversion through intercalation of polycations into a synthetic swelling mica

In order to develop a layered host material that can intercalate anionic substances, low molecular weight (8500) poly(diallyldimethylammonium chloride) (PDDA) was intercalated into a synthetic sodium fluortetrasilisic mica (Na-TSM). PDDA could coil up and create free cationic sites within the interlayer galleries of the polysilicate. The degree of polymer coiling and excess cationic charge depended on the loading of the PDDA in the host solid. The conformational change of PDDA with increasing loading was supported by powder X-ray diffraction (XRD) data as well as by calculations of Gibbs adsorption free energy through fitting experimental adsorption isotherms, which implies three different stages of the adsorption. XRD patterns indicated that PDDA/Na-TSM intercalation compounds with high polymer loading have two different interlayer environments, in which PDDA chains are coiled and stretched, respectively. The surface layer charge conversion from anionic to cationic was also directly confirmed by zeta-potential measurements. In order to evaluate the anion accepting ability of the PDDANaTSM compounds, the intercalation of a bulky acidic blue dye into the cationic interlayer was studied. The acidic dye was site-selectively intercalated into the layers in which PDDA polycation coiled. © 2007 Materials Research Society.