TY - JOUR
T1 - The electrostatic self-assembly of microgels on polymer brushes and its effects on interfacial friction
AU - Zhang, Ran
AU - Ma, Shuanhong
AU - Liu, Guoqiang
AU - Cai, Meirong
AU - Ye, Qian
AU - Yu, Bo
AU - Zhou, Feng
N1 - Publisher Copyright:
© 2016 Wiley Periodicals, Inc.
PY - 2016/12/10
Y1 - 2016/12/10
N2 - 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.
AB - 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.
KW - friction
KW - hydrophilic polymers
KW - microgels
KW - wear and lubrication
UR - http://www.scopus.com/inward/record.url?scp=84982899625&partnerID=8YFLogxK
U2 - 10.1002/app.44215
DO - 10.1002/app.44215
M3 - 文章
AN - SCOPUS:84982899625
SN - 0021-8995
VL - 133
JO - Journal of Applied Polymer Science
JF - Journal of Applied Polymer Science
IS - 46
M1 - 44215
ER -