U.S.-Australia Cooperative Research on the Synthesis of Ordered Composites on a Nanometer Sized Scale by Manipulation of Layered Compounds

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This award supports a visit by Dr. Abraham Clearfield of Texas A&M University to CSIRO, Melbourne, Australia, to work with Dr. Terry Turney. The researchers propose to combine the expertise in materials synthesis of the two institutions to synthesize novel inorganic nanocomposite materials with two related synthetic procedures. In the first, clays and other layered compounds are pillared by a variety of polycations and thermally treated to decompose the pillar into a layer of oxide sandwiched between the host layers. Compounds to be pillared include clays, tetravalent phosphates, layered hydrous oxides, layered titanates, silicic acids, layered spinels of the type K and layered double hydroxides. The latter class of compounds is pillared by polyanions. These pillared compounds will then be treated thermally to decompose the pillar into sheets of oxide sandwiched between layers of the host, thus creating ceramic nanocomposites. In the second synthetic procedure, two or more layered compounds will be exfoliated into their individual layers, mixed and reconstituted into a single phase. The exfoliates will be prepared by either attaching pendent hydrophilic organic groups to the layers or intercalating a polyether amine between the layers. A wide variety of di-, tri- and tetravalent metal compounds may be manipulated in this fashion. Reconstitution of the exfoliates will be effected by thermal removal of the organic, by acid treatment to remove intercalated amines, or by gentle alkaline hydrolysis of the phosphonates. The final annealed solids will be interlayered phosphates, hydroxides or oxides, and will constitute new types of such solids with novel catalytic, magnetic and electrical properties.