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Surfactants of natural cosmetic
Štumarová, Kamila ; Krouská, Jitka (referee) ; Jugl, Adam (advisor)
The bachelor thesis deals with the study of critical micelle concentration (CMC) of five surfactants that can be used to produce natural cosmetic products. Polysorbate 20 and 80, decyl glucoside, sulfonated castor oil and cocamidopropyl betaine were selected from the groups of non-ionic, anionic, and amphoteric surfactants. Four different methods were chosen for the experimental part of the work, namely Du Noüy ring tensiometry, isothermal titration calorimetry (ITC), high resolution ultrasonic spectroscopy (HR-US) and fluorescence spectroscopy. It was found that the CMC of all selected surfactants could be reliably determined by ring tensiometry and fluorescence spectroscopy. In contrast, no CMC value could be calculated from the results of ultrasonic spectroscopy. Only the critical micelle concentration of sulfonated castor oil could be determined by ITC. Overall, it became apparent that the selected surfactants exhibit interesting and complex behaviour that could be studied in more detail.
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