Multidimensional characterization of polyelectrolytes and interpolyelectrolyte complexes in aqueous solutions

Multidimensional characterization of polyelectrolytes and interpolyelectrolyte complexes in aqueous solutions Abstract: This PhD thesis is dedicated to the study of polyelectrolytes and their self-assembly in aqueous solutions. The morphology and ionization state of individual polymer chains were investigated as well as their co-assembly with oppositely charged species. First, the charge regulation of short and long weak polyelectrolytes in aqueous solution was investigated to deeper understand their pH-responsive properties. The changes of ionization degree and charge of oligopeptides composed of 5 amino acids with acid side-chains and 5 with basic side chains were followed upon varying the pH in order to reveal the effect of interactions between the like-charged and oppositely charged groups. It was shown that intra-molecular electrostatic interactions and conformational flexibility caused the suppression of the total charge and enhancement of ionization of the peptides. To get an insight into the distribution of local H+ concentration in the proximity of a polyelectrolyte chain, a modified polyelectrolyte structure was used with a fluorescent pH- indicator, covalently attached at the end of the chain. Ionization of the pH-responsive fluorophore revealed its effective pK which was compared with the local..