Other Areas of Research

Materials
Colloidal and Inertfacial Phenomena
Fluid Properties

Materials

In keeping with the goal of the University of establishing centers of excellence in specific research areas, another thrust of the Department of Chemical Engineering is in materials. This research includes both materials processing and materials characterization. Fundamental processing studies include electrochemical reactions, reactions in emulsions and microemulsions, sol-gel reactions, and fractal interpretations. Both analytical modeling and laboratory experimentation are involved.

Reactions in segregated media--micelles, microemulsions, vesicles, etc.--aimed toward developing new applications are being studied. Such media have several unique characteristics due to the dispersed nature of the reactive regions. For example, not only is it possible to handle extremely viscous, even solid materials while avoiding heat transfer problems, but also localized control of the composition of the reactive region can be achieved. These characteristics are being evaluated as a means of producing bulk quantities of ultrafine (<100nm) ceramics particles. By appropriate control of the process variables, monodisperse suspensions can be produced which aid in the production of low-defect final products. Of current interest here is the production of precursor particles for the 1-2-3 superconductor.

In work related to magnetic data storage, we are electrodepositing ultrathin layered alloy films and characterizing their morphology and properties. Typical model systems consist of alternating layers of ferromagnetic and nonmagnetic metal, for example, Ni/Cu/Ni trilayers or Co/Cu/Co multilayers. When the thickness of the individual layers is comparable to the mean free path of a conduction electron in a metal i.e., several nanometers, the films have novel magnetic properties that make them attractive candidates for new generation data storage materials. The roughness of the interface between ferro-magnetic and adjacent nonmagnetic regions can be controlled by choosing the deposition conditions and appears to affect the film's magnetic properties. Our work on electrodeposited ultrathin films is aimed at elucidating the connections between the electro-deposition process variables, the nanoscale film morphology, and the properties of the films. We are using a combination of experiments and modeling to study the processing, structure, and properties of these films.

Participating Faculty
KNona Liddell, Professor
509 335-3710

Bill Thomson, Professor
509 335-8580

Richard Zollars, Professor
509 335-4332

Recent Publications
R.F. Renner and K.C. Liddell, "Roughness Development in Electrodeposited Ultrathin Cobalt and Nickel Layers." J. Mater. Res., 15, 458 (2000).

Colloidal and Interfacial Phenomena

Adsorption into Hydrophobic Surfaces: The adsorption of nonionic surfactants appears to be well behaved, with the surface area occupied per adsorbed molecule increasing with increasing molecular weight of the surfactant, and with increasing polarity of the adsorbing surface. The behavior of anionic surfactants is quite different, however. Adsorption areas appear to first increase, then decrease, with increasing molecular weight for a series of sodium alkyl sulfates. Increasing the adsorbing surface charge density initially decreases the adsorption area, but ultimately results in a complete repulsion of the surfactant from the surface. These differences in behavior appear to arise from the interactions between the ionized groups chemically bound to the adsorbing surface and those on the surfactant. This study is examining the effect that these electrostatic interactions have on the adsorption area per molecule for a series of anionic surfactants. A newly developed theory for the adsorption of polymeric species into hydrophobic surfaces has also been modified to include the electrostatic forces necessary to model the adsorption of these ionic surfactants.

Participating Faculty
Richard Zollars, Professor
509 335-4332

Recent Publications
R. L. Zollars, "Ionic Absorbates on Hydrophobic Surfaces", invited chapter in Surfaces of Nanoparticles and Porous Surfaces, J. Schwarz and C. I. Contescu, Editors, Marcel Dekker, Inc., New York, 1999.

P. Blau and R. L. Zollars, "Sedimentation Field Flow Fractionation of Nonspherical Particles", Journal of Colloid and Interface Science, 183, 476 (1996).

Fluid Properties

A magnetic-coupled microbalance system has been assembled to allow extremely accurate measurements of densities of fluid mixtures, including the region very near dew-point conditions. Investigations are ongoing relative to development of improved equations of state, with practical applications in the petroleum industry.

A microwave type measurement system has been constructed and is being used to measure dielectric constants for aqueous solutions containing dissolved solids and organic compounds. This property is essential in modeling electrolyte solutions, with applications in petroleum production, water purification, geochemistry, etc. The microwave cell is also being used to investigate liquid-vapor phase change phenomena in hydrocarbon mixtures.

Participating Faculty
Reid Miller, Professor
509 335-4001

Recent Publications
G. S. Anderson, R. C. Miller and A. R. H. Goodwin, "Static Dielectric Constants for Liquid Water from 300 K to 350 K at Pressures to 13 MPa Using a New Radio-Frequency Resonator", J. Chem. Eng. Data, 45, 549 (2000).

E. F. May, R. C. Miller and Z. Shan, "Densities and Dew Points of Vapor Mixtures of Methane + Propane and Methane + Propane + n-Hexane Using a Dual-Sinker Densimeter", J. Chem. Eng. Data, (published on web July 19) to ap-pear (2001).

E. F. May, T. J. Edwards, A. G. Mann, C. Edwards and R. C. Miller, "Development of an Automated Phase Behavior Measurement System for Lean Hydrocarbon Fluid Mixtures, using Re-Entrant RF/Microwave Resonant Cavities", Fluid Phase Equilibria, 185, 339 (2001).

E. F. May, R. C. Miller and A. R. H. Goodwin, "Dielectric Constants and Molar Polarizabilities for Vapor Mixtures of Methane + Propane and Methane + Propane + Hexane Obtained with a Radio-Frequency Reentrant Cavity", submitted to J. Chem. Eng. Data (2001).