Engineering rheological response in chitosan–sophorolipid systems through controlled interactions

Abstract

The purpose of this study was to understand the impact of the biopolymer chitosan on the rheological behaviour of the biosurfactant sophorolipid as well as the effects of ionization and electrolyte addition on the chitosan-sophorolipid system. METHODS: Rotation mechanical rheometry was used to study the rheological response of the chitosan-SL systems. Frequency sweeps were conducted to analyse the rheological properties of the system at low-frequency ranges, and bulk viscosity of the system was studied at high shear rates for each sample. RESULTS: The biosurfactant sophorolipid on its own has very low viscosity. The bulk rheology results show that the addition of chitosan enhances the viscosity and viscoelastic properties of the chitosan-sophorolipid system indicating the presence of synergistic interactions between the two systems. Electrolyte addition had a significant impact on the system's rheological response. Addition of salt built the viscosity of pure chitosan. However due to charge screening effects, it resulted in a decrease in viscosity for the chitosan-sophorolipid system. On further increasing the salt concentration, an increase in viscosity was observed but not beyond the value obtained for the chitosan-SL system without any salt. An increase in pH results in increased ionization of the carboxylic acid groups in acidic SL, which in turn enhances the synergistic interactions between chitosan and SL. CONCLUSION: The strong charge interactions between chitosan and sophorolipid lead to formation of an integrated gel-like network, thus building the viscosity of the system. A variation in parameters like biopolymer concentration, electrolyte and ionic strength has the potential to modify the bulk rheological properties of the chitosan-SL system. CONCLUSION: Les fortes interactions de charge entre le chitosan et le sophorolipide conduisent a la formation d'un r eseau de type gel int egr e, renforc ßant ainsi la viscosit e du syst eme. Une variation de param etres tels que la concentration en biopolym ere, l' electrolyte et la force ionique a le potentiel de modifier les propri et es rh eologiques globales du syst eme chitosan-SL.

High Performance Conditioning Shampoo with Hyaluronic Acid and Sustainable Surfactants

“…It was shown that for both surfactant systems, the samples that did not contain any HA were low viscosity, Newtonian systems. This is understandable given that HA has the ability to help build viscosity and the surfactants alone typically have lower viscosities at a concentration of 10%, confirmed by Pingali, Benhur and Amin, as well as Moore et al [17,18]. As the concentration of HA increased in both systems, they become non-Newtonian, shear-thinning and high viscosity samples.…”

“…After analyzing the importance of each parameter, the objective is to develop a solution combining hyaluronic acid and alkyl polyglucoside or acidic sophorolipid to minimize surface tension, increasing foamability and the reduction in the wet combing force as a shear-thinning, non-Newtonian sample. Pingali, Benhur and Amin study the rheological response of sophorolipid in combination with chitosan [17]. They were able to show that the viscosity of sophorolipid alone is quite low and therefore demonstrates Newtonian behavior.…”

Methylcellulose-Chitosan Smart Gels for Hairstyling

“…For maximum benefit, proper spreadability is required for any hair product. According to Pingali et al [13], varying chitosan concentrations have a ranging viscosity between 10 −1 and 10 1 Pa.s, which is an ideal range for spreadability, pumping, and rubbing. Chitosan is commercially produced from chitin.…”

“…Not only is methylcellulose largely available, but it is also a very affordable option for a biopolymer [22]. There has been a large amount of research conducted surrounding chitosan and its ability to build up viscosity [13,14]. Several different articles have been used to understand how chitosan concentrations affect the viscosity of the sample [13,14,17,18].…”

“…There has been a large amount of research conducted surrounding chitosan and its ability to build up viscosity [13,14]. Several different articles have been used to understand how chitosan concentrations affect the viscosity of the sample [13,14,17,18]. Previous articles that have been studied prior to beginning this research have shown that ranging chitosan concentrations from 0.25% to 2.5% had consistent behavior where at low shear rates it remained a constant zero viscosity since the rate of disentanglement was the same as the rate of fresh entanglements.…”