technology Data Have Been Reported by Researchers at Swiss Federal Institute of Technology -->
By a News Reporter-Staff News Editor at Science Letter -- A new study on Nanotechnology is now available. According to news originating from Zurich, Switzerland, by NewsRx correspondents, research stated, "Nanotribological properties of silica surfaces, with and without adsorbed, brushlike copolymers of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) and poly(L-lysine)-graft-dextran (PLL-g-dextran) have been investigated in aqueous viscous solvent mixtures by means of colloid-probe lateral force microscopy. Lateral forces for PEG/dextran brushes have been measured as a function of shear velocity in aqueous mixtures of glycerol and ethylene glycol (EG), which are highly miscible with water, but are poor solvents for hydrophilic PEG and dextran chains."
Our news journalists obtained a quote from the research from the Swiss Federal Institute of Technology, "Prior to the friction measurements on polymer brushes, a nanoscale Stribeck curve was obtained on a bare silica surface in the selected aqueous cosolvent mixtures. The Stribeck curve for bare surfaces indicates the existence of a surface-solvating thin film due to the adsorption of hydrated ions, preventing direct silica-silica contact in the boundary-lubrication regime. A clear transition to the hydrodynamic regime is seen at high speeds for solvents with higher viscosities. The polymer brushes, however, show a shear-thinning effect with increasing shear speed and a combined influence of polymer film and solvent viscosity on the measured friction forces. The formation of an interfacial fluid-film is shown to shift the hydrodynamic regime of hydrated brushes to a lower value of U eta."
According to the news editors, the research concluded: "The correlation between the structural configuration and the corresponding frictional properties of the polymer brushes upon changing solvent quality is discussed."
For more information on this research see: Exploring Lubrication Regimes at the Nanoscale: Nanotribological Characterization of Silica and Polymer Brushes in Viscous Solvents. Langmuir, 2013;29(32):10149-10158. Langmuir can be contacted at: Amer Chemical Soc, 1155 16TH St, NW, Washington, DC 20036, USA. (American Chemical Society - www.acs.org; Langmuir - www.pubs.acs.org/journal/langd5)
The news correspondents report that additional information may be obtained from P.C. Nalam, ETH, Lab Surface Sci & Technol, Dept. of Mat, CH-8093 Zurich, Switzerland. Additional authors for this research include S.N. Ramakrishna, R.M. Espinosa-Marzal and N.D. Spencer (see also technology.html">Nanotechnology).
Keywords for this news article include: Zurich, Europe, Nanoscale, Switzerland, Nanotechnology, Emerging Technologies
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