Research Interests

Our solid state research group concentrates on the synthesis and characterization of new materials.

Many useful materials such as ceramics are produced from high temperature reactions (500 deg. - 3000 deg.C) which often take days due to slow solid-solid diffusion. We are developing new methods such as reactions between metal halides and alkali compounds which enable high quality refractory materials to be synthesized in seconds. Salt formation drives these reactions. For example MoS2, a useful lubricant, battery cathode and catalyst, is normally prepared by heating the elements to 1000 deg.C for several days. Our new synthesis produces pure, crystalline MoS2 from a self-initiated reaction between the solids MoCl5 and Na2S in just seconds. Refractory ceramics such as BN or ZrN (m.p.~3000 deg.C) can be produced in seconds from NaBF4 or ZrCl4 and Li3N.

We are exploring the use of conducting polymers as separation membranes for gases, liquids and ions. For example, free standing, robust films of the conducting polymer polyaniline have been cast from solution. Gas permeability tests on the polyaniline membranes have demonstrated a remarkable selectivity for gases which depends on the kinetic diameter of the gas and the doping level of the polymer.

UCLA has been at the forefront of activity in fullerene chemistry. Our group produced the first samples of pure superconducting K3C60 (Tc=19K) and Rb3C60 (Tc=30K) which enabled us to collaboratively determine their composition, structure and pressure dependence of superconductivity. Endohedral rare-earth fullerenes have been characterized by mass spectrometry and collisional probes. Synthesis and characterization of new forms of fullerenes should continue to yield exciting materials properties.