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Lignin molecular arrangements in Langmuir and Langmuir–Blodgett films: the influence of extraction processes by D. Pasquini; D.T. Balogh; O.N. Oliveira Jr.; A.A.S. Curvelo is a Materials Science article available to read on EtoBox.

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The influence of the extraction process has been investigated in the formation of Langmuir and Langmuir-Blodgett films of lignins. In order to focus on the extraction process, lignins from a single source, sugar cane bagasse, were extracted via four methods, viz. acetone-oxygen (AO), soda (SO), ethanol-water (EW) and acetone/water/sulfuric acid (SAC). Langmuir films were spread onto ultra pure water by dissolving the lignin in a mixture of N,N-dimethylacetamide (DMA) and chloroform. The major effect arises from the presence of strong polar groups, which depends on the extraction process. Lignins with larger contents of carbonyl, such as AO and EW, yielded more expanded surface pressure-area isotherms and lower surface potentials (or dipole moments). Carbonyl groups therefore contribute negatively to the surface potential, i.e. the oxygen in the carbonyl linkage somehow points to the air when the film is in the compressed state. When the subphase conditions were altered by changing temperature, pH and ionic strength, the monolayers from EW lignin were the most affected, presumably because of the different degrees of difficulty in removing the COOH groups from the water/film interfac

Who reads Lignin molecular arrangements in Langmuir and Langmuir–Blodgett films: the influence of extraction processes?

Author

D. Pasquini; D.T. Balogh; O.N. Oliveira Jr.; A.A.S. Curvelo

Publisher

Elsevier Science; Elsevier ; Elsevier BV (ISSN 0927-7757)

Published

2005

Language

EN

Field

Materials Science (Physical Sciences)