Overview of research
The focus of our work is in demonstrating innovative processing strategies for engineering functional devices and microstructures. They produce highly selective membranes and catalysts with tailored properties and may also be used for the fabrication of chemical sensors, electronic and optical components. We combine synthetic chemistry, processing, and characterization with careful evaluation of microstructures and functionality in challenging applications. Our recent publications focus on molecular sieve synthesis, crystal structure elucidation, pattern formation, morphology control, and incorporation in engineering devices. Our work is strengthened by substantial industrial interactions.
Materials Synthesis, Structure Elucidation and Modification
Microporous structures are attractive materials for many applications, including adsorption, catalysis and ion exchange. High Resolution Electron Microscopy (HREM), Powder X-ray and Neutron Diffraction as well as single crystal techniques are used in our group to elucidate the crystal structures of molecular sieve materials including new ones synthesized in our laboratory. For example, we determined the structure of titanosilicate materials synthesized by Engelhard Co. researchers and contributed to the development of the first highly selective adsorbent for natural gas purification from nitrogen. We also synthesized and determined the structure of the first layered silicate with three-dimensional porosity within the layers. These new microporous layers could be used to make polymer silicate nanocomposites that combine mechanical strength with molecular sieving properties.
Molecular Sieve Films
A processing scheme for the formation of microporous molecular sieve films is being developed. Fundamentally, this is (1) preparation of a colloidal suspension of molecular sieve crystals of nanometer dimensions; (2) deposition of a thin seed film of this suspension; and (3) secondary grain growth of the deposited zeolite nanocrystals to form a continuous film. This allows for optimization of the individual steps and rational designs tailored for the specific film application. Recently, by use of this scheme we prepared the first high flux, high selectivity molecular sieve film for xylene isomer separation.
Hydrothermal Crystal Growth
A program on zeolite nucleation and growth with the goal of developing predictive models for zeolite film formation combines experiments (in collaboration with E Kokkoli) with multi-scale simulation (in collaboration with SA Auerbach, PA Monson and DG Vlachos) and illustrates the importance of the interplay of chemistry and transport in zeolite growth and morphology.
Advancing the state-of-the art in patterned materials formation requires mimicking Nature's ability to impart functionality and multiscale ordering in single-step self-organized, self-regulated processes. We initiated a program to explore the potential of self-regulated reaction-transport systems for pattern formation in practical materials.