Areas of Research
Dr. Belfiore's Research page
Research Interests:
Electro-Optical Behavior of NanoMaterial-Reinforced Macromolecule-Metal Complexes
The primary objective of this research considers the development and analysis of hybrid materials that contain self-assembled nano-patterned arrays via simultaneous connectivity of inorganic salts to dispersed surface-modified nanomaterials and functionalized block copolymers. The presence of chemically anchored mobility-restricting nanomaterial in targeted block copolymer domains that spontaneously align will facilitate the design of materials that can withstand larger forces before failure occurs and higher temperatures prior to viscous flow or thermal degradation. These issues will be addressed by developing and characterizing organic-inorganic hybrid materials that exhibit unique architecture at the nanoscale level. Organic and inorganic building blocks, such as functionalized single-walled carbon nanotubes with tethered metal complexes, should induce synergistic modification of block copolymer properties below the order-disorder phase transition temperature. Rheological and magnetochemical measurements in the molten state support the nanoscale design of these materials. Special attention will be directed toward those metal complexes that exhibit unique magnetic and photonic properties, not observed at the macroscale, when they have nanoscale dimensions as dispersed clusters within active segments of the block copolymer. The large aspect ratio of single-walled carbon nanotubes should maximize the potential for directed connectivity between functionalized segments of the copolymer and modified surfaces of the nanomaterial. The presence of chemically anchored nanomaterial within active blocks that exhibit spontaneous nano-patterned alignment should induce synergistic effects on phase transitions and macroscopic physical properties
It is possible to explore the macroscopic consequences of ligand field stabilization (i.e., in d-block complexes) and thermally reversible coordination crosslinks, in general, in macromolecule-metal complexes, because the nanoscale structure and phase behaviour of these materials yield hybrid organic-inorganic composites with synergistic physicochemical properties. The formation of self-assembled mobility-restricting nanoclusters in solid polymeric complexes represents the underlying molecular-level phenomenon that is responsible for the unique behaviour of these materials. If ligands on more than one polymer chain occupy sites in the first-shell of a single metal center, then intermolecular coordination crosslinks form and the thermophysical properties of these complexes should be modified synergistically. These objectives are accomplished with assistance from inorganic chemistry because metal cations from the d-block and the f-block form complexes with ligands in the sidegroup of functional polymers via acid-base interactions. Hence, these cations act like magnets that induce functional polymers to occupy vacant sites in the first-shell coordination sphere of the metal center. f-Block cations can accommodate several ligands in their coordination sphere, which leads to nanoclustering of several polymeric repeat units in the vicinity of each lanthanide metal center and interesting electro-optical behaviour. At the molecular level, high-resolution carbon-13 solid state NMR, proton-carbon heteronuclear magnetic spin diffusion, and infrared spectroscopy probe micro-environmental factors that influence metal-based coordination-driven self-assembly in divalent cobalt, nickel, copper, zinc, ruthenium and palladium complexes with a variety of amorphous polymers. Fourteen trivalent metal chlorides from lanthanum to lutetium in the first-row of the f-block form complexes with poly(vinylamine) and increase its glass transition temperature significantly. Ligand substitution schemes have been proposed to explain nanocluster assemblies and gel formation, which should severely restrict polymer mobility in the vicinity of each metal cation. Terbium(III) phosphorescence (i.e., laser spectroscopy) of terbium chloride hexahydrate in interactive poly(vinylamine) host matrices with (and without) chemically anchored and plasma-functionalized single-walled carbon nanotubes reveals enhanced and considerably narrowed emission of green photons when phosphorescent-attenuating lattice waters in the first-shell are displaced by the polymer’s strong-base amino sidegroups in basic (i.e., pH =10) media. Lanthanide and transition metal compatibilizers represent an interesting application of nanocluster assemblies, where sidegroups on two immiscible polymers gravitate toward a single metal center and occupy sites in its coordination sphere. Future investigations of nanoclustering and photoluminescence will be directed toward novel block copolymers where lanthanide complexation occurs preferentially in the active blocks that form nano-patterned arrays. At Colorado State University, my research group benefits greatly from expertise at the NSF-supported laser research center, located in the Department of Electrical Engineering, where visible photon emission in macromolecular complexes with europium and terbium has been measured and photon-cascade emission in praseodymium complexes is under development. The global objective of my research is to design multicomponent solid state macromolecular systems that contain chemically anchored and functionalized nanomaterials, like plasma-treated single-walled carbon nanotubes, which exhibit interesting electro-optical behaviour.
Teaching:
Courses Taught@ Colorado State University, Department of Chemical Engineering
1) CH 331 Fluid Mechanics & Momentum Transfer
2) CH 406 Introduction to Transport Phenomena
3) CH 420 Chemical Reactor Design
4) CH 501 Classical & Statistical Thermodynamics
5) CH 502 Chemical Kinetics & Reactor Design
6) CH 503 Fundamentals of Transport Phenomena
7) CH 514 Solid State Properties of Macromolecules
8) CH 523 Thermodynamic Separation Processes
9) CH 603 Graduate Topics in Mass Transfer
Other Activities: Physical Properties of Macromolecules (table of contents) |
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Selected References: (2) LA Belfiore & SE Fenton, Nanocluster Assemblies and Molecular Orbital Interactions in Macromolecule-Metal Complexes, in Macromolecules Containing Metal & Metal-Like Elements, Volume 7, Nanoscale Interactions of Metal-Containing Polymers, Chapter 1; edited by AS Abd-El-Aziz; CE Carraher, Jr; CU Pittman, Jr; & M Zeldin; Wiley-Interscience: New York (2006), pp. 1-53, ISBN# 0-471-68440-6. (3) LA Belfiore, JJ Way & L Zhang, Transport Phenomena for Chemical Reactor Design, Kirk-Othmer Encyclopedia of Chemical Technology, Volume 25, 5th edition; Wiley: New York (2006), 269-322. (4) LA Belfiore, Effects of the Collision Integral, Thermal Diffusion, and the Prater Number on Maximum Temperature in Macroporous Catalysts with Exothermic Chemical Reaction in the Diffusion-Controlled Regime, Chemical Engineering Science, 62 (3), 655-665 (2007). (5) LA Belfiore, DC Electric Field Effects on Ehrenfest-like Relations at the Glass Transition, Polymer, submitted for publication, February (2007). (6) LA Belfiore, Soret Diffusion and Nonideal Dufour Conduction in Macroporous Catalysts with Exothermic Chemical Reaction at Large Intrapellet Damkohler Numbers, Canadian Journal of Chemical Engineering, revised manuscript submitted for publication, February (2007). |