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Published September 2023 | v1
Journal Article Open

Electroresponse of weak polyelectrolyte brushes

  • 1. ROR icon California Institute of Technology


End-tethered polyelectrolytes are widely used to modify substrate properties, particularly for lubrication or wetting. External stimuli, such as pH, salt concentration, or an electric field, can induce profound structural responses in weak polyelectrolyte brushes, which can be utilized to further tune substrate properties. We study the structure and electroresponsiveness of weak polyacid brushes using an inhomogeneous theory that incorporates both electrostatic and chain connectivity correlations at the Debye–Hückel level. Our calculation shows that a weak polyacid brush swells under the application of a negative applied potential, in agreement with recent experimental observation. We rationalize this behavior using a scaling argument that accounts for the effect of the surface charge. We also show that the swelling behavior has a direct influence on the differential capacitance, which can be modulated by the solvent quality, pH, and salt concentration.

Copyright and License

© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.


The authors acknowledge Dr. Alejandro Gallegos for useful discussions. C.B. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0020347. Z.-G.W acknowledges Hong Kong Quantum AI Lab, AIR@InnoHK of Hong Kong Government. 

This article is dedicated to Fyl Pincus, whose prolific and insightful contributions to the fields of condensed matter, polymer, and soft matter physics have left a lasting impact. The work presented here draws particular inspiration from Fyl's groundbreaking research on polyelectrolyte brushes.


C.B. and Z.-G.W. participated in the project conception, developmentment of theory, data collection, and in preparation of the manuscript.

Data Availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.


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Additional details

September 18, 2023
September 18, 2023