Measurement of the electrostatic interaction between polyelectrolyte brush surfaces by optical tweezers

Daiki Murakami, Ai Takenaka, Motoyasu Kobayashi, Hiroshi Jinnai, Atsushi Takahara

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We demonstrated an optical tweezers method to measure the electrostatic interaction between the strong polyelectrolyte brushes, poly(2-(methacryloyloxy) ethyltrimethylammonium chloride) (PMTAC), grafted on silica particles in aqueous media. The weak electrostatic interaction was successfully detected with a resolution of less than 0.1 μN m-1. The apparent Debye length, including the charge distribution in the polymer brush and the surface potential, decreased as the salt concentration in the medium increased. The experimentally obtained surface charge density was much smaller than that estimated from the amount of polyelectrolyte on the surface. Furthermore, the dissociation of ionic groups was enhanced by decreasing the grafting density of the polyelectrolyte brush. The results suggest that the majority of chloride counterions was immobilized in the dense polyelectrolyte brush layer to neutralize the high charge density.

Original languageEnglish
Pages (from-to)16093-16097
Number of pages5
JournalLangmuir
Volume29
Issue number52
DOIs
Publication statusPublished - Dec 31 2013

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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