Abstract: Friction at hydrophobic surfaces in aqueous media is ubiquitous (e.g. prosthetic implants, contact lenses), but is not well understood. Here we measure directly both normal forces and sliding friction in an aqueous environment at a stable, smooth, strongly hydrophobic surface, using a surface force balance. Our results reveal remarkable – and unexpected – effects of trapped hydrated ions, and shed strong light on lubrication and frictional dissipation at hydrophobic surfaces in water.

Speaker: 

Klein gained his BA in Physics at the University of Cambridge, where in 1977 he also received his M.A. and PhD at the Cavendish Laboratory (Department of Physics). He did his postdoc at the Weizmann Institute in Israel, and from 1980-1984 was a Senior Scientist at the Weizmann Institute and a University Demonstrator at the Cavendish Laboratory. In 1984 he was appointed Professor at the Weizmann Institute (full Professor from 1987), and subsequently headed its Polymer Research department and was Chairman of its Scientific Council. From 2000-2007 Klein was concomitantly the Dr. Lee’s Professor of Chemistry at the University of Oxford and Head of its Physical and Theoretical Chemistry Department (2000-2005). His interests in soft matter have ranged from the dynamics and interfacial properties of polymers to the behaviour of confined fluids, nanotribology and biological lubrication.