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The electrostatic self‐assembly of microgels on polymer brushes and its effects on interfacial friction
Author(s) -
Zhang Ran,
Ma Shuanhong,
Liu Guoqiang,
Cai Meirong,
Ye Qian,
Yu Bo,
Zhou Feng
Publication year - 2016
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.44215
Subject(s) - materials science , polymer , electrostatic interaction , polymer science , composite material , polymer chemistry , chemical engineering , chemical physics , chemistry , engineering
In this article, a series of monodisperse poly( N ‐isopropylacrylamide‐ co ‐acrylic acid) [P(NIPAm‐AA)] microgels were prepared with different content of acrylic acid (AA) by surfactant‐free emulsion polymerization, and their electrostatic self‐assemble and tribological behavior on polymer brushes were investigated. The ζ‐potential of microgels became more negative with the increase content of AA, which means a stronger hydration capability. For cationic poly[2‐(methacryloyloxy)ethyltrimethylammonium chloride] (PMETAC) brushes, negative P(NIPAm‐AA) microgels adsorbed on the surfaces of brushes as a result of the electrostatic interaction, and more AA content means stronger absorption ability. However, compared to the polymer brushes, P(NIPAm‐AA) 2:1 and P(NIPAm‐AA) 5:1 microgels possessed the weaker hydration capability, which led to a concomitant increase in friction of interface. In terms of P(NIPAm‐AA) 10:1 microgels, due to the weak adsorption, they could be sheared off easily, leading to the PMETAC brushes swell again, and thus, a lower friction of interface was obtained. Moreover, the tribological behavior of microgels was significantly affected by the pH, especially the P(NIPAm‐AA) 2:1 microgels exhibited good lubrication property in high pH solution due to high hydration of deprotonated carboxylic acid groups. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 44215.