Laponite As A Rheology Modifier Of Alginate Solutions: Physical Gelation And Aging Evolution

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The rheological behavior of alginate and Laponite/alginate solutions was studied. It was observed that the Cross viscosity model successfully describes the steady-state shear behavior of this polysaccharide. The scaling behavior analyzed for the entangled regime is in good agreement with polyelectrolyte solutions (G(e)similar to c(p)(3/2)), with interactions generated between the alginate and the charged surfaces of the Laponite platelets. Therefore, the effect of Laponite as a rheology modifier is influenced by the alginate concentration. Higher alginate concentrations hindered the formation of the house of cards microstructure. Frequency sweep tests were performed to analyze the transition from solid-like to liquid-like behavior in a solid-like dominated domain. Soft physical gels were obtained at low alginate concentrations. The gel point was determined (1.65 wt.% of alginate and 2 wt.% of Laponite) through the Kramers-Kronig damping factor, and time sweep tests revealed the evolution of the storage (GI and loss modulus (G") as functions of the waiting time (t(w)). The growing elasticity revealed that Laponite/alginate solutions undergo aging. (C) 2016 Elsevier Ltd. All rights reserved.15718Secretaria de Education Superior, Ciencia, Tecnologia e Innovation (SENESCYT-Ecuador)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq-Brazil) [401297/2014-4, 308660/2015-3]SENESCYT [AR2Q-8590]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq