Thomas Pinnavaia
University Distinguished Professor Office: 435 Chemistry
Phone: 517-355-9715 186 /
Websites: Research Group - Area
Awards & Honors
Genealogy/Graduates
Inorganic Materials Chemistry: Porous Structures and Nanocomposites
(Research Description PDF - 1125 kb)Functional Mesostructures. We are developing supramolecular assembly routes to mesostructured metal oxides with pore structures and surface areas effective for materials applications in adsorption and chemical catalysis. These oxides can have surface areas >1000 m2/g and uniform framework pore sizes in the range 2 - 500 nm. In characterizing these inorganic materials, we use a variety of physical techniques including NMR spectroscopy, X-ray powder diffraction, thermal analysis, among many others. We also collaborate with physicists in applying theoretical models and specialized experimental techniques such as pair distribution function analysis in order to better understanding these structures and make them more functional for materials applications. One class of mesostructured silicas of current interest have the framework pores functionalized with thiolate ligands for the trapping Hg2+ and other heavy cations from water. These materials show great promise for use as trapping agents for the purification of water. A TEM image of a typical mesostructure with a wormhole framework structure is shown at right. Note the uniformity of the framework channels (dark spaces), which in this case are about 3.0 nm in diameter.
When Hg2+ cations bind to thiolate ligands covalently immobilized on the pore walls, they bind strongly by forming electrically neutral and cationic metal complexes in which the thiolate group bridges to two metal centers and causes the metal to adopt two- or four-fold coordination, depending on the mercury loading, which can be as high as 6.33 mmole per gram of functionalized silica and corresponding to a mercury loading of 56% by weight!
Polymer Nanocomposites. Another general area of interest is the synthesis and properties of polymer nanocomposites. These are materials in which inorganic nanoparticles are dispersed in an organic polymer matrix in order to dramatically improve the strength and other performance properties of the polymer. The key to forming such novel materials is understanding and manipulating the guest-host intercalation chemistry occurring between the polymer and the inorganic nanoparticle. Once this understanding is achieved, it is possible to design nanocomposites with remarkable properties. Shown at right, for example, is a comparison of the damage suffered by a pristine epoxy polymer (lower specimen) when it is exposed to toluene and the corresponding polymer toughened through nanoparticle reinforcement (upper specimen).
Selected Publications
Thiol-functionalized Mesostructured Silica Vesicles, Jainisha Shah and Thomas J. Pinnavaia, Chem. Commun. 2005, 12, 1598?1600.Modeling the Local Structure and Energetics of Protozeolitic Nanoclusters in Hydrothermally Stable Aluminosilicate Mesostructures, Hong Li, S. D. Mahanti, and Thomas J. Pinnavaia, J. Phys. Chem. B 2005, 109, 2679?2685.
Assembly of Large-Pore Silica Mesophases with Wormhole Framework Structures from a,w-Diamine Porogens, Park I.; Wang, Z.; Pinnavaia, T. J.; Chem. Mater. 2005; 17(2); 383-386.
Lamellar Mesostructured Silicas with Chemically Significant Hierarchical Morphologies, A. J. Karkamkar, S.-S. Kim, S. D. Mahanti, T. J. Pinnavaia, Adv. Func. Mater. 2004, 14, 507?512.
Assembly of Wormhole Aluminosilicate Mesostructures from Zeolite Seeds, Liu, Y., Pinnavaia, T. J., J. Mater. Chem. 2004, 14, 1099?1103.
Gas-Oil Cracking Activity and Product Selectivity of the Hydrothermally-Stable Mesoporous Aluminosilicates (MSU-S) Assembled from Zeolite Seeds, Triantafyllidis, K.S.; Lappas, A.A.; Vasalos, I.A.; Liu, Y.; Pinnavaia, T.J., Stud. Surf. Sci Catal. 2004, 154, 2853?2860.
