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The influence of humic acids methylation on the interaction of surface active agents
Bělušová, Anna ; Weidlich, Tomáš (referee) ; Smilek, Jiří (advisor)
The presented diploma thesis deals with the study of interactions between humic acids as the main component of soil organic matter with a model organic pollutant presented by cationic surfactant Septonex (which was expected to interact positively with humic acids due to its charge) through unconventional combination of dialysis and diffusion techniques realized in diffusion cells together with isothermal titration calorimetry capable of elucidating the nature of ongoing reactions from a thermodynamic point of view. The experiments were performed with a humic acid isolated by standard isolation procedure from Leonardite (1S104H) purchased from the International Society for Humic Substances, with humic acids isolated from lignite as well as modal chernozem. The aim of the submited diploma thesis is to assess the influence of carboxyl functional groups in the structure of humic acids to interactions with Septonex. For this reason, said samples of humic acids have been modified by selective methylation of their carboxyl functional groups, which can no longer participate in interactions with ionic substances. Results from diffusion cells and isothermal titration calorimetry confirmed the assumption that Septonex interacted with all types of unmodified humic acids more than with their methylated derivatives. Despite the available literature, it was surprising that the differences in the interaction of humic acids with Septonex were not diametrically different when comparing unmodified humic acids with their methylated derivatives. The extent of these interactions was assessed through the apparent equilibrium constant Kapp determined in the diffusion (dialysis) experiments and from the course of enthalpy curves from isothermal titration calorimetry. After the experiments and their evaluation, it can be concluded that humic acids and Septonex in their interactions, due to their structures, probably apply not only electrostatic interactions, especially through available carboxyl functional groups of humic acids and positively charged hydrophilic parts of Septonex molecules, but also a significant role have a hydrophobic effect, hydrogen bonds and Van der Waals forces.
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Fluorescence correlation spectroscopy in colloid systems
Janíček, Tomáš ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This work is focused on studying of stability and interaction in colloidal systems created by micelles of surfactant CTAB in solution of hyaluronic acid and water. As method chose for this work was selected fluorescence correlation spectroscopy. As dye was used Nile red. Measurements were divided firstly by size of polymeric chain and secondly by concentration of hyaluronic acid. Purpose of this work was to find out how will CTAB particles react with different sizes and concentration of hyaluronic acid. For comparison to hyaluronic acid was used Poly(sodium-4-styrenesulfonate).
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Interactions and aggregation in hyaluronan-aminoacid-surfactant systems
Venerová, Tereza ; Velebný, Vladimír (referee) ; Pekař, Miloslav (advisor)
The effect of native hyaluronan addition on CMC of excluded surfactants (Tween 20, BETADET THC 2, SDS, CTAT a CTAB) in physiological solution (0,15 M NaCl) has been investigated by fluoresence spectroscopy with Pyrene and Nile red as probes. The greatest influence on CMC has been observed in systems with cationic surfactant. System of cetyltrimethylamonnium bromid has been closely studied. Solubilization experiments with a hydrophobic dye Sudan red has been realized and aggregation number of this system has been determinated via fluorescence quenching with cetylpyridinium chloride as quencher and Pyrene as fluorescence probe. Addition of hyaluronan (native or hydrophobicaly modified) reduces aggregation number of system.
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The influence of detergents on time to failure of high density polyethylene by full notch creep test performed in corrosive bath
Kotoučková, Simona ; Tocháček, Jiří (referee) ; Bálková, Radka (advisor)
The thesis deals with the study of the influence of concentration and different types of surfactants (Igepal CO-520, Arkopal N110, Igepal CO-890, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, dodecyltrimethylammonium bromide and Dehyton PL) on the environmental stress cracking resistance of high-density polyethylene by means of Full Notch Creep Test. Furthermore, the influence of ligamental stress (3,5; 4,0 a 4,5 MPa), pH of the prepared active environment and type of the water used as a solvent for the surfactants on the time to failure was monitored. An accelerating effect was observed at increased concentration, stress and molecular weight. Faster failure was achieved after exposure to ionic types compared to nonionic. The rate of the notch opening was determined. The brittle and ductile behavior during the process of failure was evaluated by microscopic analysis of the morphology of the fracture surfaces. Based on the pH change after the test, the stability of the active environment was evaluated. Deteriorating quality of surfactant solutions was observed. Raman spectroscopy and Fourier transform infrared spectroscopy were used to detect the surfactant on the surface of the test specimen after the test.
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Determination of tensides in waste and waste waters
Sigetová, Martina ; Repková, Martina (referee) ; Vávrová, Milada (advisor)
Surfactants belong to the surface active agents with the ability to reduce surface tension, which is used mainly in detergents and cleaners. The diploma thesis is focused on the determination of surfactants in waste and waste waters. The theoretical part describes the basic properties of surfactants, their distribution, valid legislation in the EU and SR in the field of working with these materials and a variety of analytical methods for the determination of these substances. The conclusion of the thesis is to evaluate the results of measuring the concentration of anionic surfactants, which were determined in samples of waste water and sludge.
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Influence of the temperature on hydrophobic domain quality in a biopolymer-surfactant system.
Hnyluchová, Zuzana ; Kopuletá, Ema (referee) ; Mravec, Filip (advisor)
The temperature dependence on polarity has been investigated by fluorescence spectroscopy with pyrene as a probe. Pyrene was chosen thanks to its unique sensitivity to polarity of the medium. As a biopolymer was chosen 73 kDa and 1,4 MDa hyaluronic acid. Emission spectra of pyrene were measured as a function of temperature in aqous solution of CTAB in a presence and absence of sodium chloride. The results show, that the addition of specific concentration of hyaluronic acid to the sample with CTAB, mostly doesn´t have effect to change increasing/decreasing slope of polarity with the temperature.
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Influence of pH on polyectrolyte-surfactant system
Mourycová, Jana ; Omelka, Ladislav (referee) ; Pekař, Miloslav (advisor)
In this bachelor thesis, was studied influence of pH on aggregation polyelectrolyte-surfactant system using fluorescence spectroscopy and pyrene as fluorescent probe was used. As polyelectrolyte, hyaluronan with different molecular weight was used. Two surfactants cationic surfactant cetyltrimethylamonium bromide (CTAB) and nonionic surfactants polyoxyethylene (20) (TWEEN 20) were selected for interaction with hyaluronan. In the pH range from 3 to 10, no signifact changes in the aggregate non-polar core was observed. This mean system is stable against changes in the observed pH range. At system with higher concentrations of cationic surfactant (CTAB) and higher molecular weight hyaluronan occurred phase separation and gel exclusion was observed.
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Influence of surfactants and cosmetic polysaccharides on skin parameters and human skin microbiome
Pilipenco, Alina ; Hurčíková, Andrea (referee) ; Ilona,, Matějková (advisor)
The aim of this diploma thesis was to investigate the effect of surfactants and cosmetic polysaccharides on skin parameters and its microbiome. Three surfactants were tested to determine their effect: Sodium Dodecyl Sulfate (SDS), Cocamidopropyl Betaine (CAPB), Decylglucoside (DG). Distilled water was also used for comparison. For the next part of the experimental work were selected 6 polysaccharides: high molecular weight Hyaluronic Acid (HMW HA), very low molecular weight Hyaluronic Acid (VLMW HA), Sodium Caproyl Hyaluronate (CaproylHA), Sodium Carboxymethyl -Glucan (NaCMG), Schizophyllan and Glucomannan. For comparison, placebo and untreated control (only CAPB treatment) were also included in the tests. The first part of the work is a literature search on the assigned topic, which contains the following parts: skin anatomy and its biophysical properties, skin microbiome and its functions, description of used surfactants and polysaccharides. The experimental part is mainly focused on bioengineering methods for evaluation of skin parameters and qRT-PCR to determine the relative proportion of main bacterial species of skin microbiome. First, the effect on the CT gene of 16S rDNA was analysed, and Propionibacterium acnes and Staphylococcus epidermidis strains were selected for further analysis. In conclusion are presented an overview of all properties of selected substances and assessment of their application in cosmetics.
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Assessmant of surfactants levels in waters
Zajícová, Markéta ; Doležalová Weissmannová, Helena (referee) ; Vávrová, Milada (advisor)
The present Bachelor Thesis deals with problem of water contamination by synthetic surfactants. Surfactants represent the main component of washing and cleaning agents, from which they enter waste waters. The goal of Thesis was to monitor and evaluate volume of surfactants in waste waters from waste water treatment plant VFU Brno. Samples were being taken in the course of 7 days and we have monitored volume of anionic and cationic tensides in samples from influent and effluent stream of waste water treatment plant. For qualitative and quantitative determination were used mobile analytic measurement devices with photometric detection by company Merck. Results were processed and interpreted in data evaluation section in the end of this Bachelor Thesis.
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Interaction between amphiphilic fluorescent probes and hyaluronan
Střondalová, Hana ; Vala, Martin (referee) ; Mravec, Filip (advisor)
This bachelor thesis dealt with studying the interaction of amphiphilic fluorescent probes with hyaluronan because these probes could significantly help in clarifying the links between hyaluronan and surfactants. This complex could be a great benefit in targeting drug distribution. This thesis was focused on the interaction between hyaluronan and amphiphilic fluorescent probes – specifically with dodecylacridine orange. First explored was the interaction with hyaluronan, and then with the hyaluronan – surfactant system. Cetyltrimethylamonium bromide was selected as surfactant. Samples were examined using fluorescence spectroscopy. Emission and absorption spectrum of dodecyl acridine orange was measured. This experiment was based on the hypothesis that dodecylacridine orange forms dimers as acridine orange and nonylacridine orange. It was found that in a system of hyaluronan-probe, dodecyl acridine orange was pushed out of the complex by cetyltrimethylamonium bromide, which was bounded instead. Surfactant interacts with hyaluronan binding positions - with carboxyl groups.
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