Multivalent counterions diminish the lubricity of polyelectrolyte brushes
- Univ. of Chicago, Chicago, IL (United States); Argonne National Lab. (ANL), Lemont, IL (United States); Nanyang Technological Univ. (Singapore)
- Univ. of Chicago, Chicago, IL (United States); Argonne National Lab. (ANL), Lemont, IL (United States)
- Univ. of Massachusetts, Lowell, MA (United States)
- Ben-Gurion Univ. of the Negev, Midreshet Ben-Gurion (Israel)
Polyelectrolyte brushes provide wear protection and lubrication in many technical, medical, physiological, and biological applications. Wear resistance and low friction are attributed to counterion osmotic pressure and the hydration layer surrounding the charged polymer segments. However, the presence of multivalent counterions in solution can strongly affect the interchain interactions and structural properties of brush layers. We evaluated the lubrication properties of polystyrene sulfonate brush layers sliding against each other in aqueous solutions containing increasing concentrations of counterions. The presence of multivalent ions (Y3+, Ca2+, Ba2+), even at minute concentrations, markedly increases the friction forces between brush layers owing to electrostatic bridging and brush collapse. Furthermore, our results suggest that the lubricating properties of polyelectrolyte brushes in multivalent solution are hindered relative to those in monovalent solution.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1463685
- Journal Information:
- Science, Vol. 360, Issue 6396; ISSN 0036-8075
- Publisher:
- AAASCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Quantification of Mono- and Multivalent Counterion-Mediated Bridging in Polyelectrolyte Brushes
The effect of multivalent counterions to the structure of highly dense polystyrene sulfonate brushes