A detailed molecular theory will be discussed that describes the response of weak polyelectrolyte gels to changes in salt concentration and pH of the bath solution. Our approach includes specifically the molecular details and conformational degrees of freedom of the polymeric gel. We find that the physical properties of polyacid gels in good solvent depend on the coupling between molecular interactions and charge regulation. Furthermore, we use Poisson Boltzmann theory and theoretically informed coarse-grained simulations to show the importance of charge inhomogeneity and associated coulomb interactions. Large regions of excess charge in a diffuse layer surrounding the gel are found in nanometer sized gels, collapsed gels, and gels in low salinity or high dielectric constant media. Collapse of gels by compensation of polymer charge can be induced by addition of salt.

Computational modeling of polyelectrolyte gels: Charge regulation and nanoscale phase behavior

244th National Meeting (2012)

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