Tribological properties of hydrophilic polymer brushes under wet conditions

Motoyasu Kobayashi, Atsushi Takahara

Research output: Contribution to journalArticle

102 Citations (Scopus)

Abstract

This article demonstrates a water-lubrication system using high-density hydrophilic polymer brushes consisting of 2,3-dehydroxypropyl methacrylate (DHMA), vinyl alcohol, oligo(ethylene glycol)methyl ether methacrylate, 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTAC), 3-sulfopropyl methacrylate potassium salt (SPMK), and 2-methacryloyloxyethyl phosphorylcholine (MPC) prepared by surface-initiated controlled radical polymerization. Macroscopic frictional properties of brush surfaces were characterized by sliding a glass ball probe in water using a ball-on-plate type tribotester under the load of 0.1-0.49 N at the sliding velocity of 10-5-10-1 m s-1 at 298 K. A poly(DHMA) brush showed a relatively larger friction coefcient in water, whereas the polyelectrolyte brushes, such as poly(SPMK) and poly(MPC), revealed significantly low friction coefficients below 0.02 in water and in humid air conditions. A drastic reduction in the friction coefficient of polyelectrolyte brushes in aqueous solution was observed at around 10-3-10-2 m s-1 owing to the hydrodynamic lubrication effect, however, an increase in salt concentration in the aqueous solution led to the increase in the friction coefficients of poly(MTAC) and poly(SPMK) brushes. The poly(SPMK) brush showed a stable and low friction coefficient in water even after sliding over 450 friction cycles, indicating a good wear resistance of the brush film.

Original languageEnglish
Pages (from-to)208-216
Number of pages9
JournalChemical Record
Volume10
Issue number4
DOIs
Publication statusPublished - Aug 1 2010

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Biochemistry
  • Chemical Engineering(all)
  • Materials Chemistry

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