Mesoscopic Simulations of the Phase Behavior of Aqueous EO 19 PO 29 EO 19 Solutions Confined and Sheared by Hydrophobic and Hydrophilic Surfaces

Type
Article

Authors
Liu, Hongyi
Li, Yan
Krause, Wendy E.
Pasquinelli, Melissa A.
Rojas, Orlando J.

Online Publication Date
2011-12-19

Print Publication Date
2012-01-25

Date
2011-12-19

Abstract
The MesoDyn method is used to investigate associative structures in aqueous solution of a nonionic triblock copolymer consisting of poly(propylene oxide) capped on both ends with poly(ethylene oxide) chains. The effect of adsorbing (hydrophobic) and nonadsorbing (hydrophilic) solid surfaces in contact with aqueous solutions of the polymer is elucidated. The macromolecules form self-assembled structures in solution. Confinement under shear forces is investigated in terms of interfacial behavior and association. The formation of micelles under confinement between hydrophilic surfaces occurs faster than in bulk aqueous solution while layered structures assemble when the polymers are confined between hydrophobic surfaces. Micelles are deformed under shear rates of 1 μs -1 and eventually break to form persistent, adsorbed layered structures. As a result, surface damage under frictional forces is prevented. Overall, this study indicates that aqueous triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (Pluronics, EO mPO nEO m) act as a boundary lubricant for hydrophobic surfaces but not for hydrophilic ones. © 2011 American Chemical Society.

Citation
Liu H, Li Y, Krause WE, Pasquinelli MA, Rojas OJ (2012) Mesoscopic Simulations of the Phase Behavior of Aqueous EO 19 PO 29 EO 19 Solutions Confined and Sheared by Hydrophobic and Hydrophilic Surfaces . ACS Applied Materials & Interfaces 4: 87–95. Available: http://dx.doi.org/10.1021/am200917h.

Acknowledgements
This work was partially supported by the National Textile Center under Grant C05-NS09. We thank Dr. Juan Hinestroza at Cornell University for helpful discussions.

Publisher
American Chemical Society (ACS)

Journal
ACS Applied Materials & Interfaces

DOI
10.1021/am200917h

PubMed ID
22136187

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