Interlayer Charge Conversion Through Intercalation of Polycations into a Synthetic Swelling Mica
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0988-QQ03-03
Interlayer Charge Conversion Through Intercalation of Polycations into a Synthetic Swelling Mica Hideo Hata, Yoji Kobayashi, and Thomas E. Mallouk Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802
ABSTRACT 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. INTRODUCTION Layered inorganic compounds have attracted widespread interest as versatile host materials because of their unique 2D-structure and chemical reactivity. The intercalation reactions of layered materials have been widely utilized for creating inorganic – organic assemblies with structures controlled by host – guest and guest – guest interactions, leading to a rich variety of properties and applications [1,2]. However, most conventional layered host materials have anionic layer charge except for layered double hydroxides (LDHs), so the guests are typically restricted to neutral and cation species. In addition, LDHs can be easily dehydrated below 775 K, are susceptible to contamination by atmospheric carbon dioxide, and are not stable in acids [3]. Following the pioneering studies of sequential adsorption of opposite charged polyelectrolytes by Decher et. al. [4], the Layer-by-Layer technique has been extensively studied in polymer and colloid chemistry. The key principle of this technique is alternating overcompensation of the surface charge. Based on this principle, our group recently reported the interlayer charge conversion of a clay mineral through the intercalation of high molecular weight (
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