Rheology and dynamic light scattering of octa-ethyleneglycol-monododecylether/chitosan solutions.
Carbohydr Polym
; 98(1): 321-30, 2013 Oct 15.
Article
em En
| MEDLINE
| ID: mdl-23987351
In this work we used rheometry and DLS to probe relaxation phenomena in solutions of chitosan and octa-ethyleneglycol-monododecylether. The dispersions had a marked pseudoplastic behavior, which became less evident, as surfactant concentration was increased. Arrhenius plots showed that systems with surfactant presented a characteristic temperature at which apparent enthalpy of activation (varying from 3 to 40 kJ mol(-1)) changed: this change was correlated to a possible transition of colloidal aggregates to a wormlike configuration. DLS intensity correlation functions were described by KWW equation: pure chitosan solutions had relaxation rate distributions centered at a characteristic relaxation rate around 4.6×10(-6) µS(-1); as surfactant was added, a new component, with a faster characteristic relaxation rate with a magnitude order of 10(-3) µs(-1), appeared. It was shown that the dependence between these relaxation rates and surfactant concentration could be used to describe DLS-related relaxation phenomena as an Arrhenius-activated process, agreeing with results obtained using rheometry.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Reologia
/
Espalhamento de Radiação
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Quitosana
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Etilenoglicóis
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Luz
Idioma:
En
Revista:
Carbohydr Polym
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Reino Unido