Título: | ASSEMBLY OF SODIUM N-LAURYL SARCOSINATE WITH DIFFERENTS POLYMERS | ||||||||||||
Autor: |
MATHEUS OUVERNEY FERREIRA |
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Colaborador(es): |
ANA MARIA PERCEBOM SETTE DA SILVA - Orientador |
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Catalogação: | 21/DEZ/2020 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=50953&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=50953&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.50953 | ||||||||||||
Resumo: | |||||||||||||
Surfactants derived from amino acids are molecules that exhibit a great interest in academic and industrial research, as they present characteristics such as low toxicity and high biodegradability. Within this class, N-Lauryl Sarcosinate stands out as an anionic surfactant whose application has been increasingly used to replace other anionic surfactants, such as sodium dodecyl sulfate, mainly in cosmetics. However, studies on its behavior are still scarce, mainly involving its interaction with other molecules, such as polymers. Polymers and surfactants are used together in several industrial processes and, knowing the result of their interactions is extremely important to control the properties of the mixture since they totally differ from the individual properties of its components. In this work, the study of the structures and thermodynamics of self-assembly of systems containing N-Lauryl Sarcosinate (LS) and polymers with different chemical nature: (PEG), (PSS), (PAA) and (PDADMAC) was performed using the techniques of calorimetry, tensiometry, isothermal calorimetric titration (ITC), dynamic light scattering (DLS) and Small-angle X-ray Scattering (SAXS).The results showed that the micellization of the LS occurs in the range from 10 to 14.6 nm to 298 K, with its value being dependent on the sensitivity of the technique used for its determination. The characterization of the micelle structure in water indicated that they have an ellipsoid shape and elongate with increasing concentration, but are very dependent on the pH of the medium. Also, this surfactant showed no signs of liquid-crystalline phases formation in the studied concentration range. The polymers PEG and PSS do not significantly affect the LS micellization thermodynamics. While PEG showed no evidence of any interaction with LS, PSS can act as a salt leading to the unidimensional growth of micelles. PAA may or may not interact strongly with LS depending on the solution s pH, and even induce the
formation of aggregates at concentrations below the critical micellar concentration (CMC). PDADMAC, which has a charge opposite to LS, has a strong electrostatic attraction with the surfactant, leading to phase separation, in much lower concentrations than CMC. The precipitate formed had the same structure found for high concentrations of pure surfactant. This study shows how the chemical nature of different polymers - neutral, anionic, and cationic - influences interactions with N-Lauryl Sarcosinate and, consequently, in their micellization processes and self-assembly structures. Therefore, it allows a better forecast and greater control of formulations properties in which it is desired to combine polymers and surfactants.
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