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Multidimensional characterization of polyelectrolytes and interpolyelectrolyte complexes in aqueous solutions
Murmiliuk, Anastasiia ; Štěpánek, Miroslav (advisor) ; Šachl, Radek (referee) ; Hoffmann, Ingo (referee)
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...
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Effect of acid-base equilibria on the association behaviour of polyelectrolytes
Staňo, Roman ; Košovan, Peter (advisor) ; Heyda, Jan (referee)
Title: Effect of acid-base equilibria on the association behaviour of polyelec- trolytes Author: Roman Staňo Department: Department of physical and macromolecular chemistry Supervisor: RNDr. Peter Košovan, Ph.D., Department of physical and macro- molecular chemistry Abstract: Macromolecules bearing charged monomeric units are omnipresent in the nature. Living systems utilize complex mechanisms to regulate the charge on biomacromolecules, hence controlling their structure or activity. Recently, there has been a surge in the preparation of bioinspired macromolecular mate- rials, such as drug delivery systems or self-healing hydrogels, possessing a high degree of responsivity to the external stimuli, such as pH. However, the fundamen- tal understanding of pH-based charge regulation in both natural and synthetic systems seems to be lacking, presumably because of the deficiency of suitable theoretical models and computational methods. Herein, we used coarse-grained simulations to shed light on the underyling physical principles of the relation between the pH, ionization, multivalency and structure of macromolecules. We presented a novel model of complex coacervates, and used it to describe phase equilibria and ion partitioning in such systems. Next, we explored the effects of multivalent ions and charged...
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Multidimensional characterization of polyelectrolytes and interpolyelectrolyte complexes in aqueous solutions
Murmiliuk, Anastasiia ; Štěpánek, Miroslav (advisor) ; Šachl, Radek (referee) ; Hoffmann, Ingo (referee)
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...
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Effect of acid-base equilibria on the association behaviour of polyelectrolytes
Staňo, Roman ; Košovan, Peter (advisor) ; Heyda, Jan (referee)
Title: Effect of acid-base equilibria on the association behaviour of polyelec- trolytes Author: Roman Staňo Department: Department of physical and macromolecular chemistry Supervisor: RNDr. Peter Košovan, Ph.D., Department of physical and macro- molecular chemistry Abstract: Macromolecules bearing charged monomeric units are omnipresent in the nature. Living systems utilize complex mechanisms to regulate the charge on biomacromolecules, hence controlling their structure or activity. Recently, there has been a surge in the preparation of bioinspired macromolecular mate- rials, such as drug delivery systems or self-healing hydrogels, possessing a high degree of responsivity to the external stimuli, such as pH. However, the fundamen- tal understanding of pH-based charge regulation in both natural and synthetic systems seems to be lacking, presumably because of the deficiency of suitable theoretical models and computational methods. Herein, we used coarse-grained simulations to shed light on the underyling physical principles of the relation between the pH, ionization, multivalency and structure of macromolecules. We presented a novel model of complex coacervates, and used it to describe phase equilibria and ion partitioning in such systems. Next, we explored the effects of multivalent ions and charged...
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