Interaction Between Surfaces
Measurement of the interaction between surfaces is a fairly new technology in surface chemistry. The results are relevant in the understanding of colloidal stability as well as the design of new surfaces.
Surface force apparatuses
In a surface force apparatus two mica surfaces are made to approach each other down to contact with an accuracy of 1 Å. During this approach the repulsive force between the surfaces is simultaneously measured. This measuring technology forms the basis of molecular understanding of molecules and aggregates at surfaces.
Atomic force microscopes (AFM)
Measuring the interaction between surfaces using AFM (see above) can be achieved by gluing a colloidal particle to the tip. This is termed the colloidal probe technique. By sliding the colloidal probe over the surface frictional properties can be obtained.
Elastohydrodynamic Rig
This instrument characterizes the molecular species and conformation in thin films during dynamic lubrication. It measures the film thickness and traction coefficient (friction coefficient) of lubricants in the elastohydrodynamic (EHL) lubricating regime. The instrument measures the lubricating properties in the contact formed between a steel ball loaded against a rotating glass, steel or alumina disc.