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Thursday, 05 November 2015

Prof Nicholas D. Spencer offers an ICN2 Seminar about lubrication with polymers on surfaces

The ICN2 seminar by Prof Nicholas D. Spencer, from the Department of Materials at the ETH Zürich (Switzerland), was introduced by Prof Daniel Ruiz, Group leader of the ICN2 Nanostructured Functional Materials Group.

Prof Nicholas D. Spencer, from the Department of Materials at the ETH Zürich (Switzerland), visited ICN2 on November 5, 2015. His Seminar entitled "Lubrication with polymers on surfaces" was introduced by Prof Daniel Ruiz, Group leader of the ICN2 Nanostructured Functional Materials Group.

The principal areas of the speaker's research are surface functionalization and characterization, with a particular emphasis on their application in tribology, implant materials, and biosensors. Atomic force microscopy and the surface forces apparatus play an important role in his group, as well as imaging versions of more traditional surface analytical methods, such as XPS and SIMS. Recently, optical and other methods for the in situ measurement of surface-macromolecule interactions have been increasingly emphasized. Over the last few years, he has been working intensively in the area of surface-chemical and surface-morphology gradients.

During his talk, Prof Nicholas D. Spencer explained how nature lubricates with water, but water is an appallingly bad lubricant by itself. Nature often overcomes this limitation by using molecules that adsorb to surfaces and contain highly hydrophilic side-chains (sugars) that render the surfaces slippery. According to the speaker, polymer brushes are man's attempt to imitate this mechanism, and when grafted on surfaces they have been shown, over the last couple of decades, to be highly effective in lubrication. Their effect on friction can be dramatic, especially in cases where contact pressures are relatively low (such as in the contact of soft surfaces).

While some issues with wear remain, their application in both oil and aqueous environments opens new possibilities in a number of applications. Some of these are quite unexpected, such as their significant influence on the rheology of dense slurries of significant potential impact on the construction industry, and, indirectly, on the environment.