Arrangements of Interlayer Quaternary Ammonium Ions in a Layered Silicate, Octosilicate

The ion exchange of octosilicate With a series of quaternary organoammonium ions was examined. The ion exchange proceeds almost quantitatively to replace the interlayer sodium ions. When n-alkyltrimethylammonium ions were exchanged with sodium ions, the basal spacings increased with the alkyl chain length, showing the formation of paraffin type surfactant aggregates in the interlayer space. When the organic cations with complex molecular geometry (dimethyldioctadecylammonium, N-(alpha-trimethylammonioacetyl)-didodecyl-L-glutamate, and O,O',O ''-tridodecanoyl-N-(omega-trimethyl ammoniodecanoyl)-tris(hydroxymethyl)aminomethane) were used, the basal spacings changed as a function of the molecular weight of the intercalated guest species. It is speculated that the molecular geometries of the intercalated species are flexible to form densely packed nanostructures in the interlayer space.