Thermodynamics
NC State's Department of Chemical & Biomolecular Engineering is the home of the new Laboratory for Molecular Thermodynamics and Computer Simulation, co-directed by Professors Carol Hall and Keith Gubbins. Their collaboration in this laboratory helps make NC State's chemical and biomolecular engineering thermodynamics programs among the strongest in the Nation.Professor Gubbins, a member of the National Academy of Engineering, joined the Chemical & Biomolecular Engineering Department at NC State in 1998. In his research, advanced molecular simulation methods are being used to develop realistic molecular models for the fabrication of nano-porous materials, such as silicates and active carbons, which open the way to the design of improved forms of these materials for separations and reactions. Further work is aimed at understanding the effects of confinement in these materials on phase transitions and chemical reactions.
In Professor Hall's group, molecular thermodynamics and computer simulation are used to study polymer equations of state and phase equilibria, with applica tion to polymer melts, blends, and composites, and to co-polymers. Students are also modeling the motions of entangled polymer molecules in melts and the swelling of polymer gels. Novel studies of the folding and aggregation of proteins are being performed, the goal being to understand how and why certain solutes, such as polyethylene glycol and chaperones, hinder protein aggregation. Other studies are aimed at modeling chiral drug separations that are based on crystallization.
Professor Peter Kilpatrick has long-term involvement in surfactant research and is currently interested in ways in which surfactants, proteins, and mesogens aggregate, adsorb, and generally modify interfaces. The results of these efforts have profound implications for enzyme immobilization, emulsification, understanding membrane-driven biological phenomena, and templating polymeric and ceramic microstructures. A current problem is the role that asphaltene aggregation and network formation play in the stabilization of emulsions formed during oil spills, crude oil transportation, and heavy crude upgrading. This phenomenon is very similar to the adsorption and networking of proteins at oil-water interfaces in the preparation of food and pharmaceutical emulsions and foams. The goal of this work is a mechanistic understanding for systematic design and treatment of emulsions.
Characterization and stability analysis of microstructured, or complex, liquids are of interest to Professor Spontak. Microscopy and scattering techniques are employed in Professor Spontak's lab to study asphaltene aggregates, block copolymers in selective solvents, and self-associating and hydrophobically modified polymers that produce supramolecular assemblies or gels. Professor Spontak is also active in thermodynamic modeling of microphase-ordering in block copolymer melts, and bond fluctuation simulations of end-grafted chain mixtures in confined geometries.
Computer simulation of adsorption of nitrogen at 77K in a model silica controlled pore glass, with an average pore diameter of 3.8nm, at various reduced pressures. P is the pressure of the bulk nitrogen gas, Po is the vapor pressure of nitrogen (1 atm), grey molecules are solid (glass), and white molecules are nitrogen. The glass was prepared by a spinodal decomposition and mimics the laboratory preparation of the glass, and the pores are fully connected.
