Theory of charge formation within polyelectrolyte layers
Charge formation within surface-confined polyelectrolyte layers (PL), including biopolymer films, is of highest importance in the application of biomedical materials in demanding products. However, due to the lack of adequate analytical tools the impact of electrical charging on the intra- and intermolecular structure of surface-confined PL so far remained poorly understood. To address this problem we work on the development of theories for the charging in PL with homogeneous and non-homogeneous distribution of ionisable groups. Systematic investigations revealed that surface conductivity measurements provide a unique opportunity for the characterization of charge formation processes within PL by Donnan and surface potentials.
Figure: Ion distribution (left) and potential distribution (right) near a surface covered with a negatively charged polyelectrolyte layer (H. Ohshima, Colloids Surf. A 1995, 103, 249). The Donnan and surface potential can be calulated based on surface conductivity measurements for any degree of dissociation.
S. S. Dukhin, R. Zimmermann, C. Werner J. Colloid Interface Sci. 2004, 274, 309‑318.
S. S. Dukhin, R. Zimmermann, C. Werner J. Colloid Interface Sci. 2005, 286, 761-773.
S. S. Dukhin, R. Zimmermann, C. Werner J. Colloid Interface Sci. 2008, 328, 186-195.