Rheology properties of Dodecyl-β-D-maltoside stabilised mineral oil-in-water emulsions

Niraula, B. and King, T.C. and Misran, M. (2003) Rheology properties of Dodecyl-β-D-maltoside stabilised mineral oil-in-water emulsions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 231 (1-3). pp. 159-172. ISSN 0927-7757

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Abstract

Rheology properties of dodecyl-β-D-maltoside stabilized mineral oil-water (o-w) emulsions were studied. A strain controlled Rheometer was used for this purpose. Shear sweep was carried out to observe the η(γ) behavior, whereas oscillatory sweep was carried out to observe the G�(�) and G�(�) behaviors. All rheology properties examined in this work including η(γ), �(γ) G�(�) and G�(�) were found to be exhibiting typical non-linear power law dependence. η-γ profiles suggested that these sample do not exhibit zero shear rate limiting viscosity and terminal relaxation time, that η of these samples decays exponentially as a function of both the γ and surfactant concentration with a characteristic power law index, exponent of which decreases with surfactant concentration. Plot of �(γ) suggested that � was not a linear function of γ at low-shear rate domain, but an exponentially growing function with a certain power exponent. At zero shear rate the stress response was not zero, implying that samples under investigation were shear thinning non-ideal plastic-like materials, with characteristic �Y response. Much like η which increased with surfactant concentration at any given shear rate, both �Y and η0 increased with surfactant concentration. Analysis of � dependence of dynamic moduli suggested that at a very low � domain below 1Hz, the G� response of these samples was dominant over G� response, and that the G� response was a more or less a linear function of �, suggesting that these samples are solid-like materials. On the other hand, at higher � domain beyond 1Hz, the G� response of these samples was dominant over G� response, but neither G�(�) was found to be a linear function of � 2, nor G�(�) a linear function of �, implying that the samples under examination were neither liquid-like nor solid-like materials. These in turn suggested that these samples cannot be characterized by Maxwell model type fluid flow behavior. Both the dynamic moduli decreased with surfactant concentration. Cole-Cole plot representing G� response against G� strongly deviated from the usual semi-circle characteristic of Maxwell model type fluid flow behavior, further confirming that these samples do not exhibit Maxwell model type fluid flow behavior. While tanδ grew linearly as a function of �, it was comparably high in both the low and high � domain, implying that these o-w emulsion exhibited more liquid-like viscous behavior than solid-like elastic behavior. The tanδ was both � and surfactant concentration dependent. While it decreased with both the surfactant concentration and � at low-frequency domain, it was almost independent of both the surfactant concentration and �.

Item Type: Article
Uncontrolled Keywords: Cole-Cole plot Emulsion Lauryl maltoside Loss modulus Phase angle Rheology Shear thinning non-Newtonian flow Storage modulus Visco-elastic property Yield stress Emulsions Rheometers Shear strength Surface active agents Water Oscillatory sweep Colloids chemical compound dodecyl beta dextro maltoside mineral oil surfactant unclassified drug article concentration (parameters) elasticity flow kinetics flow measurement liquid model oscillation priority journal sample viscosity
Subjects: Q Science > QD Chemistry
Divisions: Faculty of Science > Dept of Chemistry
Depositing User: miss munirah saadom
Date Deposited: 09 Jul 2013 00:43
Last Modified: 20 Oct 2014 07:57
URI: http://eprints.um.edu.my/id/eprint/6857

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