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Utilization of thermal and structural analyses in study on the formation of polyelectrolyte complexes
Řiháčková, Barbora ; Sedláček, Petr (referee) ; Krouská, Jitka (advisor)
This bachelor thesis deals with a study of the polyelectrolyte complexes made by chitosan and humic acids. The work was motivated by the research in the field of new materials which can be potentially useful for agricultural and medical applications. A degree and a character of the interactions were studied by isothermal titration calorimetry and dynamic light scattering method. The calorimetric experiments proved that decreasing concentration of samples causes decreasing of reaction enthalpy. Moreover, the temperature changes during the titration are not influenced by water molecules as environment but mostly by the interactions between the functional groups of chitosan and humic acids. The formation of polyelectrolyte complexes was proved also by measurements of intensity of scattered light and Z-average of particle size.
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Light Scattering Techniques in the Study on Formation of Polyelectrolyte Complexes in the System Biopolymer-Surfactant
Valečková, Vendula ; Smilek, Jiří (referee) ; Kalina, Michal (advisor)
This master thesis is dealing with the use of light scattering techniques in the study on formation of polyelectrolyte complexes in the system biopolymer-surfactant. Sodium hyaluronate was chosen as biopolymer and cetyltrimethylammonium bromide and karbethopendecinium bromide were selected as surfactants. The first precipitation experiments were performed to determine the optimal concentration range of surfactants for subsequent titration measurements performed on Zetasizer Nano ZS and for SEC-MALS analysis. The key parameters obtained from these measurements were the values of critical aggregation concentrations in hyaluronate-surfactant systems. It was found out that the increasing molecular weight of hyaluronan in these systems is causing reduction of obtained values of critical aggregation concentrations. Changes of Z-average particle size, zeta potential, polydispersity index, conformation plot, radius of gyration and molecular weight in the hyaluronan-surfactant system were monitored during experiments.
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Utilization of the polyelectrolyte complexes in medicine and cosmetics.
Karásková, Iva ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This thesis is focused on the possibilities of polyelectrolyte complexes of humic acid and chitosan. In the experimental part, based on a literature search, were optimized appropriate procedures for preparing such complexes in hydrogel form. The main aspects of the preparation, the effect was studied, the influence of the direction of the addition, the concentration, pH and ionic strength. Furthermore, the encapsulation method was tested to give chitosan pearls. Work was aimed for cosmetic and medical applications.
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Microcalorimetric and Light Scattering Methods in the Study of Interactions in Biopolymer - Surfactant System
Šojdrová, Kamila ; Mravec, Filip (referee) ; Krouská, Jitka (advisor)
Biopolymer surfactant systems have been studied by using different physico chemical methods. As the biopolymer, it was chosen high (1400–1600 kDa), medium (250–450 kDa) and low (8–15 kDa) molecular weight sodium hyaluronate. Two cationic surfactants – cetyltrimethylammonium bromide (CTAB) and carbethopendecinium bromide (Septonex) were selected to provide polyelectrolyte complexes with oppositely charged hyaluronan. The critical aggregation concentration of the surfactant in the system was monitored by dynamic light scattering (Zetasizer Nano ZS). SEC-MALS method was used for the description of the conformation of sodium hyaluronate of different molecular weights and polyelectrolytes complexes hyaluronan surfactant after reaching the aggregation point. Isothermal titration calorimetry (ITC) was used to determine the critical aggregation concentration of the surfactant by monitoring the thermal changes accompanying the aggregation of the system. It was found out that the increasing molecular weight of hyaluronan in these systems decreases the critical aggregation concentrations and conversely.
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Characterization of polyelectrolyte complexes using structural and thermal analysis
Řiháčková, Barbora ; Smilek, Jiří (referee) ; Krouská, Jitka (advisor)
This master thesis deals with study of chitosan-lignohumate, chitosan-polystyrenesulfonate, chitosan-alginate and chitosan-carrageenan polyelectrolyte complexes. The work was motivated by research of finding suitable alternative substance for lignohumate. The molecular weights of substances were characterized using SEC-MALLS. A degree and a character of the interactions between polyelectrolyte were studied by isothermal titration calorimetry and dynamic light scattering method. The calorimetric experiments proved that decreasing concentration of samples causes decreasing of heat flow. The best calorimetric measurements were provided by adding chitosan into polymer solution. The interactions between chitosan and polyanions and influence of mixing order were proved also by measuring intensity of zeta potential, Z-average of particle size and turbidity. New chitosan-based materials have a big potential in agriculture and medicine.
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Nanoparticles based on complexes of hydrophilic block polyelectrolytes and new gemini ionic surfactants
Šomšáková, Katarína ; Uchman, Mariusz Marcin (advisor) ; Trhlíková, Olga (referee)
This bachelor thesis deals with preparation and study of the aqueous solutions of block polyelectrolyte poly(2-vinylpyridine)-b-poly(ethylen oxide), P2VP-PEO with gemini surfactants 6,6'-(ethan-1,2-diylbis(oxy)) bis(3-dodecylbenzenesulfonate acid), 6,6'- (buthan-1,4-diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) and 6,6'-(hexane-1,6- diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) complexes and with P2VP-PEO and sodium dodecylsulfate, SDS, complexes, and compares their physico-chemical properties. Formed particles were characterized by static and dynamic light scattering, zeta potential, isothermal titration calorimetry and transmission cryo-electron microscopy. Even small amount of surfactant leads to coassembly of P2VP-PEO with surfactants, formed by PEO shell and P2VP/surfactant core. The nanoparticles of block polyelectrolyte and gemini surfactants in 0.1M HCl are stable and their size depends on the spacer lenght and the surfactant/polymer ratio.
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Microcalorimetric and Light Scattering Methods in the Study of Interactions in Biopolymer - Surfactant System
Šojdrová, Kamila ; Mravec, Filip (referee) ; Krouská, Jitka (advisor)
Biopolymer surfactant systems have been studied by using different physico chemical methods. As the biopolymer, it was chosen high (1400–1600 kDa), medium (250–450 kDa) and low (8–15 kDa) molecular weight sodium hyaluronate. Two cationic surfactants – cetyltrimethylammonium bromide (CTAB) and carbethopendecinium bromide (Septonex) were selected to provide polyelectrolyte complexes with oppositely charged hyaluronan. The critical aggregation concentration of the surfactant in the system was monitored by dynamic light scattering (Zetasizer Nano ZS). SEC-MALS method was used for the description of the conformation of sodium hyaluronate of different molecular weights and polyelectrolytes complexes hyaluronan surfactant after reaching the aggregation point. Isothermal titration calorimetry (ITC) was used to determine the critical aggregation concentration of the surfactant by monitoring the thermal changes accompanying the aggregation of the system. It was found out that the increasing molecular weight of hyaluronan in these systems decreases the critical aggregation concentrations and conversely.
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Nanoparticles based on complexes of hydrophilic block polyelectrolytes and new gemini ionic surfactants
Šomšáková, Katarína ; Uchman, Mariusz Marcin (advisor) ; Trhlíková, Olga (referee)
This bachelor thesis deals with preparation and study of the aqueous solutions of block polyelectrolyte poly(2-vinylpyridine)-b-poly(ethylen oxide), P2VP-PEO with gemini surfactants 6,6'-(ethan-1,2-diylbis(oxy)) bis(3-dodecylbenzenesulfonate acid), 6,6'- (buthan-1,4-diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) and 6,6'-(hexane-1,6- diylbis(oxy)) bis(3- dodecylbenzenesulfonate acid) complexes and with P2VP-PEO and sodium dodecylsulfate, SDS, complexes, and compares their physico-chemical properties. Formed particles were characterized by static and dynamic light scattering, zeta potential, isothermal titration calorimetry and transmission cryo-electron microscopy. Even small amount of surfactant leads to coassembly of P2VP-PEO with surfactants, formed by PEO shell and P2VP/surfactant core. The nanoparticles of block polyelectrolyte and gemini surfactants in 0.1M HCl are stable and their size depends on the spacer lenght and the surfactant/polymer ratio.
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Light Scattering Techniques in the Study on Formation of Polyelectrolyte Complexes in the System Biopolymer-Surfactant
Valečková, Vendula ; Smilek, Jiří (referee) ; Kalina, Michal (advisor)
This master thesis is dealing with the use of light scattering techniques in the study on formation of polyelectrolyte complexes in the system biopolymer-surfactant. Sodium hyaluronate was chosen as biopolymer and cetyltrimethylammonium bromide and karbethopendecinium bromide were selected as surfactants. The first precipitation experiments were performed to determine the optimal concentration range of surfactants for subsequent titration measurements performed on Zetasizer Nano ZS and for SEC-MALS analysis. The key parameters obtained from these measurements were the values of critical aggregation concentrations in hyaluronate-surfactant systems. It was found out that the increasing molecular weight of hyaluronan in these systems is causing reduction of obtained values of critical aggregation concentrations. Changes of Z-average particle size, zeta potential, polydispersity index, conformation plot, radius of gyration and molecular weight in the hyaluronan-surfactant system were monitored during experiments.
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Characterization of polyelectrolyte complexes using structural and thermal analysis
Řiháčková, Barbora ; Smilek, Jiří (referee) ; Krouská, Jitka (advisor)
This master thesis deals with study of chitosan-lignohumate, chitosan-polystyrenesulfonate, chitosan-alginate and chitosan-carrageenan polyelectrolyte complexes. The work was motivated by research of finding suitable alternative substance for lignohumate. The molecular weights of substances were characterized using SEC-MALLS. A degree and a character of the interactions between polyelectrolyte were studied by isothermal titration calorimetry and dynamic light scattering method. The calorimetric experiments proved that decreasing concentration of samples causes decreasing of heat flow. The best calorimetric measurements were provided by adding chitosan into polymer solution. The interactions between chitosan and polyanions and influence of mixing order were proved also by measuring intensity of zeta potential, Z-average of particle size and turbidity. New chitosan-based materials have a big potential in agriculture and medicine.
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