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Mechanical and Transport Properties of Hybrid Hydrogel Systems
Klímová, Eliška ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This master´s thesis deals with the study on mechanical and transport properties of hybrid hydrogel systems. Considering applications of hydrogels, especially in chemical industry, pharmacy, or eventually medical applications, for the study gellan and alginate-based hydrogels were selected. In order to compare individual characteristics physical and hybrid hydrogels were prepared. Gellan hydrogels were prepared in deionization aqua solution, calcium chloride dihydrate and tween 80 solution. Alginate hydrogels were prepared in calcium chloride dihydrate solution as well, and polyacrylamide with N,N´–methylenbisacrylamide. For the study of mechanical properties moisture analyser and rheology measurements were selected. Transport properties were studied using the diffusion experiments combined with UV-VIS spectroscopic detection. Concluding of this thesis is summarization of measured values, which provides comprehensive review of the problematics. It was discovered that the conveniently selected concentrations of structural components of hydrogel matrix and the additives can influence both the mechanical as well as the transport properties of studied hydrogels.
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Structural and transport properties of hybrid hydrogels with application utilization
Zhurauliova, Darya ; Pekař, Miloslav (referee) ; Smilek, Jiří (advisor)
The presented diploma thesis deals with the preparation and subsequent characterization of structural and transport properties of hybrid hydrogels based on polyvinyl alcohol and sodium alginate concerning their application potential. The thesis aims to study the current state of the solved issue on the topic of characterization of structural and transport (release) properties of hybrid hydrogels about their use in various branches of human activity and also based on literature research to propose and optimize a suitable preparation procedure and to carry out a series of experiments for their characterization. With regard to the literature research, suitable polymers capable of gelation, such as polyvinyl alcohol (PVA) and natural polysaccharide – sodium alginate, were selected for the preparation of hydrogels. The preparation of this hybrid network involved the physical cross-linking of PVA by freezing and thawing and ionic cross-linking of sodium alginate with calcium ions. By combining these polymers, viscoelastic, swelling and transport properties were determined by using physicochemical methods. Rheological measurements were performed to study the mechanical properties - specifically oscillation and amplitude tests. The structural properties of hydrogels (or xerogels) were determined, by scanning electron microscopy. The transport (release) properties of gel systems were determined by diffusion experiments with the UV-VIS spectrometry detection method, in which an organic dye (methylene blue) was used as a model probe. Another aim of this diploma thesis is to modify the internal structure of hybrid hydrogels with suitable reagents, ie., lecithin. The presence of lecithin in the hybrid hydrogel three-dimensional network serves as a model of the phospholipid bilayer, forming the cell membrane or occurring in tissues, and thus has a significant effect on rheological and transport properties. Physicochemical methods also determined the mechanical, swelling and transport properties of hybrid hydrogels with the addition of lecithin. The conclusion of this work is a summary of measured data to provide a comprehensive overview of this issue. The results suggest that the presence of sodium alginate in the PVA structure reduces the mechanical properties, although the presence of lecithin increases the strength of the hybrid hydrogels. However, by comparing all measurement results, it is possible to determine that sodium alginate, resp. lecithin affects the properties and structure of the hydrogel, which makes it possible to correct the properties of hybrid gel systems according to the required applications.
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Structural and transport properties of hybrid hydrogels with application utilization
Zhurauliova, Darya ; Pekař, Miloslav (referee) ; Smilek, Jiří (advisor)
The presented diploma thesis deals with the preparation and subsequent characterization of structural and transport properties of hybrid hydrogels based on polyvinyl alcohol and sodium alginate concerning their application potential. The thesis aims to study the current state of the solved issue on the topic of characterization of structural and transport (release) properties of hybrid hydrogels about their use in various branches of human activity and also based on literature research to propose and optimize a suitable preparation procedure and to carry out a series of experiments for their characterization. With regard to the literature research, suitable polymers capable of gelation, such as polyvinyl alcohol (PVA) and natural polysaccharide – sodium alginate, were selected for the preparation of hydrogels. The preparation of this hybrid network involved the physical cross-linking of PVA by freezing and thawing and ionic cross-linking of sodium alginate with calcium ions. By combining these polymers, viscoelastic, swelling and transport properties were determined by using physicochemical methods. Rheological measurements were performed to study the mechanical properties - specifically oscillation and amplitude tests. The structural properties of hydrogels (or xerogels) were determined, by scanning electron microscopy. The transport (release) properties of gel systems were determined by diffusion experiments with the UV-VIS spectrometry detection method, in which an organic dye (methylene blue) was used as a model probe. Another aim of this diploma thesis is to modify the internal structure of hybrid hydrogels with suitable reagents, ie., lecithin. The presence of lecithin in the hybrid hydrogel three-dimensional network serves as a model of the phospholipid bilayer, forming the cell membrane or occurring in tissues, and thus has a significant effect on rheological and transport properties. Physicochemical methods also determined the mechanical, swelling and transport properties of hybrid hydrogels with the addition of lecithin. The conclusion of this work is a summary of measured data to provide a comprehensive overview of this issue. The results suggest that the presence of sodium alginate in the PVA structure reduces the mechanical properties, although the presence of lecithin increases the strength of the hybrid hydrogels. However, by comparing all measurement results, it is possible to determine that sodium alginate, resp. lecithin affects the properties and structure of the hydrogel, which makes it possible to correct the properties of hybrid gel systems according to the required applications.
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|
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Mechanical and Transport Properties of Hybrid Hydrogel Systems
Klímová, Eliška ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This master´s thesis deals with the study on mechanical and transport properties of hybrid hydrogel systems. Considering applications of hydrogels, especially in chemical industry, pharmacy, or eventually medical applications, for the study gellan and alginate-based hydrogels were selected. In order to compare individual characteristics physical and hybrid hydrogels were prepared. Gellan hydrogels were prepared in deionization aqua solution, calcium chloride dihydrate and tween 80 solution. Alginate hydrogels were prepared in calcium chloride dihydrate solution as well, and polyacrylamide with N,N´–methylenbisacrylamide. For the study of mechanical properties moisture analyser and rheology measurements were selected. Transport properties were studied using the diffusion experiments combined with UV-VIS spectroscopic detection. Concluding of this thesis is summarization of measured values, which provides comprehensive review of the problematics. It was discovered that the conveniently selected concentrations of structural components of hydrogel matrix and the additives can influence both the mechanical as well as the transport properties of studied hydrogels.
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