Abstract
Long-ranged forces between surfaces in a liquid control effects from colloid stability1 to biolubrication2, and can be modified either by steric factors due to flexible polymers3, or by surface charge effects4. In particular, neutral polymer ‘brushes’ may lead to a massive reduction in sliding friction between the surfaces to which they are attached5,6,7, whereas hydrated ions can act as extremely efficient lubricants between sliding charged surfaces8. Here we show that brushes of charged polymers (polyelectrolytes) attached to surfaces rubbing across an aqueous medium result in superior lubrication compared to other polymeric surfactants. Effective friction coefficients with polyelectrolyte brushes in water are lower than about 0.0006–0.001 even at low sliding velocities and at pressures of up to several atmospheres (typical of those in living systems). We attribute this to the exceptional resistance to mutual interpenetration displayed by the compressed, counterion-swollen brushes, together with the fluidity of the hydration layers surrounding the charged, rubbing polymer segments. Our findings may have implications for biolubrication effects, which are important in the design of lubricated surfaces in artificial implants, and in understanding frictional processes in biological systems.
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References
Napper, D. H. Polymeric Stabilization of Colloidal Dispersions (Academic, London, 1983)
Dowson, D. (ed.) Proc. Inst. Mech. Eng. H Vol. 201 (special issue on biolubrication) 189–247 (1987).
de Gennes, P. G. Polymers at an interface: A simplified view. Adv. Colloid Interface Sci. 27, 189–207 (1987)
Israelachvili, J. N. Intermolecular and Surface Forces (Academic, London, 1992)
Klein, J., Kumacheva, E., Mahalu, D., Perahia, D. & Fetters, L. Reduction of frictional forces between solid surfaces bearing polymer brushes. Nature 370, 634–636 (1994)
Grest, G. S. Normal and shear forces between polymer brushes. Adv. Polym. Sci. 138, 149–182 (1999)
Kilbey, S. M. II, Schorr, P. A. & Tirrell, M. in Dynamics of Small Confining Systems IV (eds Drake, J. M., Grest, G. S., Klafter, J. & Kopelman, R.) 181–187 (Materials Research Society, Pittsburgh, PA, 1999)
Raviv, U. & Klein, J. Fluidity of bound hydration layers. Science 297, 1540–1543 (2002)
Klein, J. & Kumacheva, E. Simple liquids confined to molecularly thin layers. I. Confinement-induced liquid to solid phase transitions. J. Chem. Phys. 108, 6996–7009 (1998)
Pashley, R. M. Hydration forces between mica surfaces in aqueous electrolyte solutions. J. Colloid Interface Sci. 80, 153–162 (1981)
Raviv, U., Laurat, P. & Klein, J. Fluidity of water confined to sub-nanometre films. Nature 413, 51–54 (2001)
Tadmor, R., Rosensweig, R. E., Frey, J. & Klein, J. Resolving the puzzle of ferrofluid dispersants. Langmuir 16, 9117–9120 (2000)
Raviv, U., Giasson, S., Frey, J. & Klein, J. Viscosity of ultra-thin water films confined between hydrophobic or hydrophilic surfaces'. J. Phys. Condens. Matter 14, 9275–9283 (2002)
Gohy, J. F., Antoun, S. & Jerome, R. Self-aggregation of PMMA-b-PSGMA copolymers. Polymer 42, 8637–8645 (2001)
Abraham, T., Giasson, S., Gohy, J.-F., Jerome, R. & Stamm, M. Adsorption kinetics of a hydrophobic-hydrophilic diblock polyelectrolyte at the solid-aqueous solution interface. Macromolecules 33, 6051–6059 (2000)
Witten, T., Leibler, L. & Pincus, P. Stress-relaxation in the lamellar copolymer mesophase. Macromolecules 23, 824–829 (1990)
Wijmans, C. M., Zhulina, E. B. & Fleer, G. J. Effect of free polymer on the structure of a polymer brush and interaction between 2 polymer brushes. Macromolecules 27, 3238–3248 (1994)
Klein, J. Shear, friction, and lubrication forces between polymer-bearing surfaces. Ann. Rev. Mater. Sci. 26, 581–612 (1996)
Miklavic, S. J. & Marcelja, S. Interaction of surfaces carrying grafted polyelectrolytes. J. Phys. Chem. 92, 6718–6724 (1988)
Pincus, P. Colloid stabilization with grafted polyelectrolytes. Macromolecules 24, 2912–2919 (1991)
Misra, S., Tirrell, M. & Mattice, W. Interaction between polyelectrolyte brushes in poor solvents. Macromolecules 29, 6056–6060 (1996)
Borisov, O. B., Zhulina, E. B. & Birshtein, T. M. Diagram of states of a grafted polyelectrolyte layer. Macromolecules 27, 4795–4803 (1994)
Csajka, F. S., Netz, R. R., Seidel, C. & Joanny, J.-F. Collapse of polyelectrolyte brushes: Scaling theory and simulations. Eur. Phys. J. E 4, 505–513 (2001)
Raviv, U. et al. Properties and interactions of physigrafted end-functionalised poly(ethylene glycol) layers. Langmuir 18, 7482–7495 (2002)
Raviv, U., Tadmor, R. & Klein, J. Shear and frictional interactions between adsorbed polymer layers in a good solvent. J. Phys. Chem. B 105, 8125–8134 (2001)
de Gennes, P. G. Scaling Concepts in Polymer Physics (Cornell Univ. Press, Ithaca, NY, 1979)
Ferry, J. D. Viscoelastic Properties of Polymers, 3rd edn (Wiley, New York, 1985)
Claesson, P. M. & Ninham, B. W. pH dependent interactions between adsorbed chitosan layers. Langmuir 8, 1406–1412 (1992)
Ruths, M., Sukhishvili, S. A. & Granick, S. Static and dynamic forces between adsorbed polyelectrolyte layers (quaternized poly-4-vinylpyridine). J. Phys. Chem. B 105, 6202–6210 (2001)
Derjaguin, B. V., Churaev, N. V. & Muller, V. M. Surface Forces (Plenum, New York, 1987)
Kampf, N., Raviv, U. & Klein, J. Normal and shear forces between adsorbed and gelled layers of chitosan, a naturally occurring cationic polyelectrolyte. Macromolecules (submitted)
Acknowledgements
We thank J. Frey for the STAI synthesis, and R. Tadmor, T. Witten, D. Lukatsky and P. Pincus for discussions. We also thank the Eshkol Foundation (U.R.), the Canadian Friends of the Weizmann Institute (Charpak-Vered Fellowship, S.G.), the US-Israel BSF, the Deutsche-Israelische Program, and the Israel Science Foundation for their support of this work. J.F.G. (Chargé de Recherches by FNRS) and R.J. thank the SSTC for financial support.
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Raviv, U., Giasson, S., Kampf, N. et al. Lubrication by charged polymers. Nature 425, 163–165 (2003). https://doi.org/10.1038/nature01970
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DOI: https://doi.org/10.1038/nature01970
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