Polyelectrolytes Near Solid Surfaces

Citation

Balzer, Christopher James (2023) Polyelectrolytes Near Solid Surfaces. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/kga2-1820. https://resolver.caltech.edu/CaltechTHESIS:05162023-233932300

Abstract

Polyelectrolytes are ubiquitous in nature and in the products we use daily. The combination of their connectivity and charge lead to many useful properties in solution and near surfaces. Electrostatic forces dominate much of the behavior of charged species near solid surfaces; however, nonelectrostatic forces arising ion specific interactions or from varying polymer chemistry play an important role in tuning electrolyte and polyelectrolyte properties. The balance of these forces depends on factors like the salt concentration, solution pH, and properties of the surface. The current work outlines the thermodynamics of charged systems and investigates the structure and phase behavior of polyelectrolytes near solid surfaces. In particular, the work covers the thermodynamic aspects of preferential adsorption of small ions in electric double layers, polyelectrolyte adsorption, polymer-mediated interactions of surfaces using strong and weak electrolytes, surface phase transitions and contact angles of complex coacervates on solid surfaces, complexation-induced conformational phase transitions of polyelectrolyte brushes, and electro-swelling of weak polyelectrolyte brushes. The wide variety of problems addressed here reflects the variety of applications of polyelectrolytes and contexts in which polyelectrolytes appear.

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