Issue 75, 2017, Issue in Progress

Rheological reversibility and long-term stability of repulsive and attractive nanoemulsion gels

Abstract

In this research, the stability of sodium dodecyl sulfate (SDS)-stabilized canola oil nanoemulsion gels was investigated as a function of repeated rotational shear, oscillatory strain and storage time. Nanoemulsion gels, termed nanogels, were formed from oil-in-water nanoemulsions, prepared with various concentrations of SDS to get a range of droplet sizes, interdroplet interactions, and gel strengths. Repulsive nanogels were formed with 0.5, 1 and 2 times the critical micelle concentration (CMC), while attractive nanogels were prepared with 5, 10 and 15 times the CMC of SDS. No change in droplet size of the nanoemulsions was observed over a period of 90 days and an accelerated gravitation study indicated extremely high stability against creaming. All nanogels showed a remarkable recovery in viscosity and gel strength during repeated shear and strain sweep experiments, respectively. Interestingly, the elastic storage moduli (G′) for the repulsive nanogels significantly decreased, converting the nanogels into flowable weak gels. For attractive nanogels, the decrease in G′ was less. It was proposed that generation of surface active components due to lipid oxidation may alter the interfacial composition and ultimately reduce the thickness of the charge cloud leading to a reduction in G′ in the repulsive nanogels. For attractive nanogels, the uptake of lipid oxidation products in the excess micelles and their inter-droplet transfer led to a decrease in the attractive depletion interactions and charge cloud, with subsequent loss of the gel structure. The nanogels possess great potential for use in food and related soft materials provided the loss of gel strength with time could be prevented.

Graphical abstract: Rheological reversibility and long-term stability of repulsive and attractive nanoemulsion gels

Supplementary files

Article information

Article type
Paper
Submitted
29 Aug 2017
Accepted
21 Sep 2017
First published
10 Oct 2017
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2017,7, 47818-47832

Rheological reversibility and long-term stability of repulsive and attractive nanoemulsion gels

V. V. Erramreddy, S. Tu and S. Ghosh, RSC Adv., 2017, 7, 47818 DOI: 10.1039/C7RA09605D

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements