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The Utilization of Light Scattering Techniques for the Study on Hydrogel Gelation
Candráková, Simona ; Smilek, Jiří (referee) ; Kalina, Michal (advisor)
This bachelor thesis focuses on the study of hydrogel gelation using light scattering methods. For these purposes two different biopolymers (agarose and sodium alginate), with different sol to gelation phase transition, were selected. In the case of agarose, the gelation is caused by temperature change. On the other side, the gelation of sodium alginate is initiated by addition of polyvalent cations. In the experimental part of the work, agarose gelation was studied by DLS, temperature gradients of agarose solutions (40 – 30 °C) were measured. During the measurement the particle size distributions in the solutions having different concentrations were monitored as well as the temperature influence on the diffusion coefficient. The DLS method provided the values of the gelling temperatures of the solutions at a concentration of 0,5 wt.% and 1,0 wt.%. Furthermore, the DLS microrheology method was used, where temperature dependences of viscoelastic characteristics of agarose solutions (40 – 30 °C) were also measured, from which the gelling temperatures of agarose solutions of 0,1 wt.% and 0,5 wt.% were evaluated. The classical rheology was also used in the work to compare the viscoelastic behaviour of the samples and to determine the gelation point of the agarose solutions. By this method were determined gelling temperatures for all studied concentration of agarose (0,1 wt.%, 0,5 wt.% and 1,0 wt.%). The DLS method was also used to monitor the interactions of sodium alginate with the addition of Ca2+ ions, these interactions were then also evaluated and discussed in the experimental part.
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Adhesion Properties of Semi-IPN Hydrogels
Candráková, Simona ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This Diploma thesis deals with optimization of the hydrogel preparation with various additions of substances affecting adhesion, studying the adhesion of prepared hydrogel systems and modifying their adhesion properties. Prepared hydrogels were agarose, alginate and gellan polymer systems with additions of acrylic acid, acrylamide, calcium chloride and Tween 20. The experimental part of the diploma thesis focuses first on optimizing the preparation of individual hydrogels, from which, according to certain criteria, suitable representatives were selected to study adhesion and its controlled modification. Agarose and gellan hydrogels were selected as suitable representatives, which were then used in rheological measurements. Based on these measurements, the effect of the adhesive force and the adhesive work of individual materials was evaluated. It was found that the best adhesion properties of the materials used are unadjusted hydrogels, in the case of hydrogels with the addition of another substance, a negative effect on adhesion was observed, when the adhesion force was reduced and also the adhesion work was reduced.
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Adhesion Properties of Semi-IPN Hydrogels
Candráková, Simona ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This Diploma thesis deals with optimization of the hydrogel preparation with various additions of substances affecting adhesion, studying the adhesion of prepared hydrogel systems and modifying their adhesion properties. Prepared hydrogels were agarose, alginate and gellan polymer systems with additions of acrylic acid, acrylamide, calcium chloride and Tween 20. The experimental part of the diploma thesis focuses first on optimizing the preparation of individual hydrogels, from which, according to certain criteria, suitable representatives were selected to study adhesion and its controlled modification. Agarose and gellan hydrogels were selected as suitable representatives, which were then used in rheological measurements. Based on these measurements, the effect of the adhesive force and the adhesive work of individual materials was evaluated. It was found that the best adhesion properties of the materials used are unadjusted hydrogels, in the case of hydrogels with the addition of another substance, a negative effect on adhesion was observed, when the adhesion force was reduced and also the adhesion work was reduced.
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The Utilization of Light Scattering Techniques for the Study on Hydrogel Gelation
Candráková, Simona ; Smilek, Jiří (referee) ; Kalina, Michal (advisor)
This bachelor thesis focuses on the study of hydrogel gelation using light scattering methods. For these purposes two different biopolymers (agarose and sodium alginate), with different sol to gelation phase transition, were selected. In the case of agarose, the gelation is caused by temperature change. On the other side, the gelation of sodium alginate is initiated by addition of polyvalent cations. In the experimental part of the work, agarose gelation was studied by DLS, temperature gradients of agarose solutions (40 – 30 °C) were measured. During the measurement the particle size distributions in the solutions having different concentrations were monitored as well as the temperature influence on the diffusion coefficient. The DLS method provided the values of the gelling temperatures of the solutions at a concentration of 0,5 wt.% and 1,0 wt.%. Furthermore, the DLS microrheology method was used, where temperature dependences of viscoelastic characteristics of agarose solutions (40 – 30 °C) were also measured, from which the gelling temperatures of agarose solutions of 0,1 wt.% and 0,5 wt.% were evaluated. The classical rheology was also used in the work to compare the viscoelastic behaviour of the samples and to determine the gelation point of the agarose solutions. By this method were determined gelling temperatures for all studied concentration of agarose (0,1 wt.%, 0,5 wt.% and 1,0 wt.%). The DLS method was also used to monitor the interactions of sodium alginate with the addition of Ca2+ ions, these interactions were then also evaluated and discussed in the experimental part.
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