Joan E Curry
Associate Department Head, Environmental Science
Member of the Graduate Faculty
Professor, BIO5 Institute
Professor, Environmental Science
Primary Department
(520) 626-5081
Research Interest
Joan Curry, PhD, stands in the field of research related to interfacial chemistry, which is a focus within physical chemistry. Within interfacial chemistry, she focuses on chemistry of molecules at the interfaces where solids and liquids come together. The term solid here includes mineral and bacterial surfaces found in soils and sediments, metal and oxide machine surfaces and cell surfaces found in the human body. Molecules can be water and ions that bathe soil surfaces, organics that lubricate machine parts and large biomacromolecules, such as proteins and lipopolysaccharides, attached to cells that mediate cell adhesion. Her specific interests are: 1) determining the effect of confinement on liquids in general and lubricants in particular and 2) characterizing the adhesive properties of cell surface biomacromolecules. The primary goal of this work is to understand how biomacromolecules that cover cell surfaces influence the interaction and adhesion of cells with other cells and with solid surfaces. Cells can be either bacteria or human cells. It is important to understand bacterial adhesion because it is the first step in biofilm formation, which has numerous undesirable consequences ranging from heat exchanger fouling to medical implant infections. Currently, very little is known about how bacterial surface biomacromolecules mediate adhesion and therefore it is still not possible to control or manipulate the process. Human cell adhesion is also mediated by biomacromolecules, in particular proteins that bind to one another through specific lock and key mechanisms. The structure of many cell adhesion proteins is well known but their function is still poorly understood. In collaboration with Ronald Heimark (Surgery), Dr. Curry is working to understand how heavy metals such as cadmium affect the binding of cell adhesion proteins called cadherins. This work will help scientists understand better how heavy metals may lead to birth defects and in adults could accelerate cardiovascular disease. This work is experimental and involves direct force measurements between biomembrane covered mica surfaces with the Surface Forces Apparatus (SFA). With the SFA it is possible to measure the magnitude and distance dependence of molecular forces acting between two flat surfaces with angstrom and nanonewton resolution.

Publications

Curry, J. E., & Cushman, J. H. (1997). Normal-strain induced change in lattice-type for confined cyclohexane films. Materials Research Society Symposium - Proceedings, 464, 115-120.

Abstract:

One to three layer cyclohexane films confined between mica-like surfaces are studied to elucidate changes in the film's lattice-type. The laterally confined film in equilibrium with the bulk fluid that is well into the liquid regime of its phase diagram. Monte Carlo simulations are conducted at constant chemical potential, temperature, and V = Ah, where A is the lateral area and h is the separation between the walls. One and two layers of fluid freeze as h increases. The one layer fluid has a triangular lattice, while the two layer fluid exhibits first a square lattice and then a triangular lattice with increasing surface separation. In contrast to previous studies, solidlike order is induced primarily by the strong fluid-solid interaction and is largely a function of pore width. A shift in the relative alignment of the surfaces perturbs the solidlike fluid structure but does not cause the sudden shear melting transition associated with epitaxial alignment of the fluid atoms with the surface. There is a correlation between the shear stress calculated in the computer experiments and that measured in Surface Forces Apparatus experiments.

Hogan, D. E., Curry, J. E., Pemberton, J. E., & Maier, R. M. (2017). Rhamnolipid biosurfactant complexation of rare earth elements. JOURNAL OF HAZARDOUS MATERIALS, 340, 171-178.
BIO5 Collaborators
Joan E Curry, Raina Margaret Maier
Curry, J. E., & Cushman, J. H. (1998). Structure in confined fluids: Phase separation of binary simple liquid mixtures. Tribology Letters, 4(2), 129-136.

Abstract:

One- to five-layer cyclohexane and octamethyltetracyclosiloxane (OMCTS) films confined between mica-like surfaces are studied to elucidate changes in the lattice type and composition of the films. Grand canonical ensemble Monte Carlo computer simulations are used to study the laterally confined film. In contrast to previous studies, solid-like order is induced primarily by the strong fluid-solid interaction and is largely a function of pore width. Solid-like order within the layers causes the composition of the pore fluid to shift from the bulk composition, favoring either cyclohexane or OMCTS, depending on the pore width. A shift in the relative alignment of the surfaces perturbs the solid-like fluid structure but does not cause the sudden shear melting transition associated with epitaxial alignment of the fluid atoms with the surface.

Curry, J. E., & Kim, S. (2014). Adhesion: Coated Surface, Effects of Humidity. Dekker Encyclopedia of Nanoscience and Nanotechnology, Third Edition.
Curry, J. E., & Christenson, H. K. (1996). Adsorption, wetting, and capillary condensation of nonpolar fluids in mica slits. Langmuir, 12(23), 5729-5735.

Abstract:

The adsorption behavior of n-pentane and cyclohexane in mica slits at room temperature has been studied as a function of chemical potential and gap width with multiple-beam interferometry. The measured film thicknesses close to saturation for large slit widths (effectively isolated surfaces) range up to 7 nm with n-pentane (at a relative vapor pressure of 0.9996) and 3 nm with cyclohexane (at a relative vapor pressure of 0.995). The thickness of these adsorbed wetting films is slightly larger than that predicted by van der Waals theory. The difference may be accounted for by thermal fluctuations of the adsorbed liquid-vapor interface. At smaller slit widths a capillary condensation transition occurs as the slit fills up with liquid. The separation at which this occurs is in good agreement with a film-thickening mechanism due to van der Waals forces across the gap only for the thickest films (t ≥ 6 nm). For thinner films the capillary condensation transition occurs at larger than expected slit widths, and the deviations are large for t ≤ 3 nm. We speculate that these larger-than-expected condensation separations are related to a fluctuation-enhanced film thickness in this regime. The work demonstrates the utility of measurements in a system consisting of a single slit-pore, without the complications of polydispersity and connectivity of pore networks. The results show that vapor adsorption isotherms can be measured with multiple-beam interferometry, i.e., in the surface force apparatus.