Polyelectrolytes are synthetic or biological macromolecules with multiply charged backbones. These charges are compensated by counterions. Polyelectrolytes interact strongly with surfaces of opposite charge, a phenomenon that is widely exploited to prepare stabilized surfaces (e.g. colloids and fibers) and to assemble nanolayered films such as multilayers. The driving forces for polyelectrolyte adsorption and/or interaction to/with oppositely charged interfaces are usually analyzed in terms of electrostatics. However, in aqueous solutions, the driving forces for adsorption are best described by ion-exchange or place-exchange reactions among and between charged polyelectrolyte segments and counterions. In particular, the release of bound counterions, along with their waters of hydration, is a universal driving force for adsorption. In this talk, simple equilibrium arguments will be used to describe what drives polyelectrolytes to charged interfaces and how salt concentration moderates the driving forces.

Driving forces for polyelectrolyte adsorption at charged interfaces

244th National Meeting (2012)

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