ISOTOPE SUBSTITUTION OF INTERFACIAL FLUIDS IN VERMICULITE CLAYS

We are using neutron diffraction to investigate the interlayer structu re of alkyl-ammonium substituted vermiculite clays. In the case of pro pyl- and butyl-ammonium these clays exhibit macroscopic expansion to f orm 1D colloidal gels with interlayer spacings of up to 1000 Angstrom. Experiments in conjunction with isotope substitution were used to com pare the position and orientation of counterions and water molecules c onfined between the clay surfaces in methyl-ammonium and butyl-ammoniu m vermiculite.