Monolayers and thin films of dextran hydrophobically modified

Abstract

Foram sintetizados uma série de copolímeros enxertados biodegradáveis pelo enxerto da e-captolactona sobre dextrana de diferentes pesos moleculares. Os polímeros obtidos foram caracterizados por infravermelho com transformada de Fourier, ressonãncia magnética nuclear, termogravimetria e análise elementar. Monocamadas estáveis na interface ar-água e filmes finos de revestimento por rotação foram preparados e caracterizados pela técnica de Langmuir e por medidas de angulo de contato. A compressibilidade e elasticidade estática superficial das monocamadas e a energia de superfície dos copolimeros de filme finos mostram dependência com a quantidade de e-caprolactona. Desses resultados pode-se concluir que as propriedades de superfície de polímeros enxertados podem ser moduladas pela sua composição. Adicionalmente, de acordo com esses resultados, dextranas enxertadas com e-caprolactona mostram potencial para serem usadas em diferentes aplicações onde as propriedades de superfície são importantes.A series of biodegradable graft copolymers were synthesized by grafting e-caprolactone over dextran of different molecular weights. The obtained copolymers were characterized by Fourier transform infrared spectroscopy FTIR, proton nuclear magnetic resonance 1 H NMR, thermogravimetry and elemental analysis. Stable monolayers at the air-water interface and spin coated thin films were prepared and characterized by the Langmuir technique and by contact angle measurements respectively. The compressibility and static surface elasticity of the monolayers and the surface energy of copolymer thin films show dependence with the e-caprolactone content. From these results it can be concluded that the surface properties of grafted copolymers can be modulated by their composition. Additionally, according to the obtained results, e-caprolactone grafted-dextrans show potential for being used in different applications where surface properties are important.

Extracellular polysaccharides produced by bacteria of the Leuconostoc genus

“…Already natural, chemically unmodified dextrans have film-forming properties (Pavlov et al 1999), which, when supplemented with plasticizers (glycerol, sorbitol) or other biopolymers, allow the formation of edible coatings for fruits, berries and other products (Quezada Gallo et al 2005;Davidović et al 2018;Moncayo-Martinez 2013). The film-forming properties of dextrans and their varied applications expand when their chemical modifications are used, such as esters (Liebert et al 2011), derivatives of furfuryl-and maleimido carboxylic acids (Elschner et al 2017) or alkylamines (Trivedi et al 2017), also the hydrophobically modified copolymer obtained by grafting of caprolactone over the dextran backbone (Leiva et al 2010). The film-forming properties also promote the use of dextran in nanoparticle coatings (Wasiak et al 2016), such as cerium (Yazici et al 2015), iron oxide (Naha et al 2019) or various macroporous metallic and metal oxide sponges (Walsh et al 2003).…”

Understanding and controlling the structure of thin polymer films used in photolithography

“…Therefore, a study of the surface free energy (SFE) through contact angle measurements is one of the most common techniques to study the polymer and copolymer thin films. A number of literature studies have reported the contact angles and surface free energy of polymer and copolymer thin films [333][334][335][336][337][338][339][340][341][342],…”