Ph.D. Victoria University, New Zealand, 1986
B.S. Victoria University, New Zealand, 1978
Liquid Surface Physics
My research is centered around liquid surfaces, the structural phase transitions that can occur on them, and the surface forces that induce these structural transitions. The physics of liquid surfaces, thin films, and competitive surface adsorption is rather poorly understood despite its importance in many technological and biological processes such as catalysis, electrolysis, and osmosis. Depending upon the liquids and the surfaces under consideration, the liquid can become structured where the composition and molecular orientational alignment varies with depth into the liquid. These effects are strongly influenced by the van der Waals interaction between the liquid and the surface, the presence and strength of the dipole—image dipole interaction in the vicinity of a surface (for polar liquids), and the liquid thermodynamics, namely, the proximity to any bulk fluid phase transitions. If the system of interest is near a second-order phase transition (or critical point) then this surface structuring may extend for hundreds of molecules into the liquid.
We have been studying this liquid structuring using a variety of optical techniques, such as, interferometry and ellipsometry. Currently we are using x-ray and neutron reflectometry/scattering (at a number of national facilities within the U.S.) and atomic force microscopy to provide us with additional information about the composition, orientational ordering and surface forces that are acting. This work is being conducted in collaboration with scientists in Germany, France, Great Britain and the U.S.
In the coming nanotechnology revolution, micro and nano-fluidics will play a key role in many processes involving complex fluids. For example, one of the dreams of the future is the creation of smart pills containing hundreds of micro-pills where each micro-pill would only release drugs into the blood stream at sites where a chemical deficiency was detected -- a much safer and more efficient strategy than the currently used 'saturation' delivery scheme. Of course, in order to understand the dynamics of micro-pills in the vicinity of a wall (eg. your blood vessel) the adsorption structure and surfaces forces that act (and which we are studying) will be important.
- National Science Foundation
Recent Selected Publications
B. M. Law, M. D Brown, L. Marchand, L. B. Lurio, W. A. Hamilton, I. Kuzmenko, T. Gog, S. Satija, E. Watkins and J. Majewski, "Adsorption at liquid interfaces: A comparison of multiple experimental techniques", European Physical Journal 168, 127 (2009).
E. J. Stalcup, R. Seemann, S. Herminghaus and B. M. Law "Dissipation mechanisms in ionic liquids", J. Coll. Interf. Sci., 338, 523 (2009).
S. P. McBride and B. M. Law, "Viscosity dependent liquid slip at molecularly smooth hydrophobic surfaces", Phys. Rev. E 80, 060601(R) (2009).