Preparação de filmes de celulose contendo nanopartículas de prata produzidas em meio de líquido iônico

• Ano de defesa: 2018
• Autor(a) principal: Silva, Douglas Santos da [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Cellulose; Nanoparticles; Silver; Films; Ionic liquid; Celulose; Nanopartículas; Prata; Filmes; Líquido iônico
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=6358512; https://repositorio.unifesp.br/handle/11600/52795

The development of methods that use biopolymers as a support for the immobilization of metallic nanoparticles is of growing interest. Among biopolymers, cellulose is the most indicated because it is natural, abundant and non-toxic, but its insolubility and its poor processability are obstacles to be overcome. This study developed a new method for producing cellulose films (CEL) containing silver nanoparticles (AgNPs) produced in ionic liquid medium, called hexadecylpiridinium salicylate (HDPSal). The cellulose used in this work was a unmodified polymer, which was dissolved in an ionic liquid, 1-butyl-3-methylimizadiole chloride (BMImCl) 2.5% (w/w). This solution was regenerated by the addition of water, affording a transparent and resistant film. In this process of dissolution and regeneration of cellulose, it was transformed from type I to type II. The silver nanoparticles (AgNPs) were produced from the chemical reduction of silver nitrate dissolved in water with tetrabutylammonium borohydride (TBABH4) in the presence of different concentrations of HDPSal. Obtaining of AgNPs in all the samples was proved by the presence of the surface plasmon resonance (SPR) band of silver in nanometric scale around 415 nm. The assays for determination of minimum inhibitory concentrations showed that the microbicidal action of these dispersions was due to the ionic liquid (HDPSal), which surrounds the silver nanoparticles, stabilizing them by electrostatic effect. All prepared AgNPs in HDPSal were impregnated at cellulose films. It was possible to confirm the impregnation of the AgNPs, in the films, by the presence of the SPR band around 420 nm in all films. The AgNP impregnation process did not cause any change in the primary structure of the cellulose, although it modified to type II. In addition to the AgNPs, HDPSal was also impregnated in the film during the process. From the recorded images on a scanning electron microscope, AgNPs smaller than 100 nm were distributed homogeneously throughout the film. All films showed antimicrobial action against E. coli and S. aureus, and higher concentration of silver films showed activity against C. albicans. In this sense, the microbicidal action at films was attributed to the silver nanoparticles.