The research interests of the materials chemistry group are in the preparation and chemical and physical properties of novel inorganic materials.
The chemistry of materials is one of the two ares of chemistry experiencing the greatest growth at the present time both in academic institutions and industry. This popularity can be associated with the pervasiveness of solids throught our lives, from semiconductors through energy storage to geological/biological systems, and to a number of recent breakthroughs, including high-temperature inorganics superconductors.
One aspect of our work is in finding new synthetic routes to prepare metastable compounds that cannot be prepared by traditional techniques. Primary emphasis is on reacting ions in solution with solids, so that the ions diffuse into the solids giving, for example, enhanced superconductivity. In many cases it is possible to form previously unknown open structures by diffusing ions out of existing structures creating vacant tunnels or layers in which chemistry may be perfomed or separations/catalysis carried out. These reactions can be followed using electrochemical, x-ray, gravimetric and standard chemical methods, among others.
A second aspect is the study of ionic motion in solids and its use in electrochromic devices and batteries. Here much emphasis is on the intercalation compounds of the transition metal oxides and sulfides, and the research involves both high and low temperature chemistry. Of particular interest are the tungsten bronze compounds, NaxWO3, which can be prepared with a variety of tunnel sizes. Single crystals of these compounds are being grown and characterized using x-ray analysis. Closely related is an investigation of naturally occuring single crystal aluminoscilicates which can swell in the presence of water and other solvents and have been implicated as playing a critical role in diagenetic processes. These compounds are excellent systems for performing chemistry on the molecular level, and have the potential for revolutionizing the are of nanocomposites.
Hydrothermal synthesis of new metastable phases: preparation and intercalation of a new layered titanium phosphate, Yingjeng James Li and M. Stanley Whittingham, Solid State Ionics, 63, 391 (1993)
Variable-Range-Hopping Conduction and the Poole-Frenkel Effect in a Copper Polyaniline Vermiculite , M. Kellicutt, I. S. Suzuki, C. R. Burr, M. Suzuki, M. Ohashi and M. Stanley Whittingham, Phys. Rev. B47, 13664, (1993)
Intercalation Compounds, in Fast Ion Transport in Solids, eds. B. Scrosati et al, NATO ASI series, 250, 69 (1993).
Tungsten Oxides and Bronzes: Synthesis, Diffusion and Reactivity, Jing-Dong Guo and M. Stanley Whittingham, Int. J. Modern Physics, 7, 4145 (1993).
Hydrothermal Synthesis of a New Molybdate with a Layered Structure, Jingdong Guo, Peter Zavalij and M. Stanley Whittingham, Chem. Mater., 6, 357 (1994).
Hydrothermal Synthesis of New Oxide Materials Using the Tetramethyl Ammonium Ion, Proc. Int. Meeting on Soft Chemistry, Nantes, France, Sept. 1993, M. Stanley Whittingham, J. Li, J-d Guo and P. Zavalij, Materials Science Forum Vols. 152/153, 99, (1994).
Preparation and Characterization of a MoO3 with Hexagonal Structure, J. Guo, P. Zavalij, and M. S. Whittingham, Eur. J. Solid State Chem, 31 (1994) November.
Hydrothermal Synthesis of Electrode Materials: Pyrochlore Tungsten Trioxide WO3 Film, J. Guo, Y. J. Li, and M. S. Whittingham, J. Power Sources, (1994) In press.
Metastable Hexagonal Molybdates: Hydrothermal Preparation, Structure and Reactivity, J.-D. Guo, P. Zavalij, and M. S. Whittingham, J. Solid State Chem, in press (1994).
The Hydrothermal Synthesis of New Oxide Materials, M. S. Whittingham, J.-D. Guo, R. Chen, T. Chirayil, G. Janauer, and P. Zavalij, Solid State Ionics, 75 (1995) February.
"The Role of Synthesis and Structure in Solid State Ionics - Electrodes to Superconductors," in Recent Advances in Fast Ion Conducting Materials and Devices, eds. B.V.R. Chowdari et al. (World Scientific, 1990).
"Mixed Conductors - Synthesis, Properties and Applications," MRS Bulletin, September 1989.
"Chemistry of Hight Temperature Superconductors," American Chemical Society Symposium Series #352 (1987).
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