Estudo da influência de óleos vegetais em sistemas estabilizados por tensoativos a base de nanopartículas de TiO2 para aplicação em protetores solares multifuncionais

• Ano de defesa: 2019
• Autor(a) principal: Santana, Bárbara Vasconcelos
• Orientador(a): Kaminski, Renata Cristina Kiatkoski
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Química
• Palavras-chave em Português: Química; Câncer de pele; Cristais líquidos; Emulsões; Dióxido de titânio; Óleos vegetais; Óleo de coco; Protetores solares; Microemulsão; Pentaclethra macroloba; Cocos nucifera L
• Palavras-chave em Inglês: Sunscreens; Liquid crystals; Microemulsion; Titanium dioxide
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/11965

Crystalline liquid and microemulsions systems were prepared, formed by the ternary surfactant / oil / water mixture (T / O / A), using as oil phases Pracaxi oil (Pentaclethra macroloba) and Coconut oil (Cocos nucifera L.). With the aim of studying its effects on the structure and occlusive capacities of the systems. Initially, the formulations were prepared by varying the amounts of surfactant (TWEEN 80) present in their composition and were studied by SAXS and flow rheology. It was observed that the increase in the amount of surfactant in the systems caused the occurrence of a mixture of cubic phases, giving the system gel-like viscous structure. The formulations containing 30% of surfactant presented a suitable pseudoplastic character for use in sunscreens, thus, TiO2 was added thereto and they were studied by SAXS and flow rheology. The results indicated that the addition of the nanoparticles to the formulations causes a change in the interaction between their components and in the case of the formulation containing coconut oil, there was also a change in their structure. This result may be related to a hypothesis still under study, which suggests the formation of a micellar system of the type core-shell. The physical stability of the systems was studied by flow rheology, from the analyzes it was observed that the formulations without the presence of the nanoparticles showed a tendency to maintain their stability over time. The inverse effect occurred in the formulations with the presence of TiO2, because due to the increase of surface charges in the system, it showed a decrease in its stability with time. The in vitro occlusive capacity of the formulations was measured by the Vringer method. Firstly, the amounts of water and oil of the formulations were varied with 30% surfactant. The results showed the tendency to increase the occlusive capacity in the formulations containing larger amounts of oil, by the formation of a hydrophobic film that reduces the water loss of the system. In formulations with Pracaxi oil, this occlusive capacity was increased with the addition of TiO2 due to the ability of the nanoparticles to form a film after application. The inverse behavior was observed for the systems containing the nanoparticles and the Coco oil, a fact that may indicate a change in the structure of the system, which is being studied and has already been indicated in the results of SAXS and rheology.