Issue 11, 2020

A single-component photorheological fluid with light-responsive viscosity

Abstract

Viscoelastic fluids whose rheological properties are tunable with light have the potential to deliver significant impact in fields relying on a change in flow behavior, such as in-use tuning of combined efficient heat-transfer and drag-reduction agents, microfluidic flow and controlled encapsulation and release. However, simple, single-component systems must be developed to allow integration with these applications. Here, we report a single-component viscoelastic fluid, capable of a dramatic light-sensitive rheological response, from a neutral azobenzene photosurfactant, 4-hexyl-4′butyloxymonotetraethylene glycol (C6AzoOC4E4) in water. From cryo-transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS) and rheology measurements, we observe that the photosurfactant forms an entangled network of wormlike micelles in water, with a high viscosity (28 Pa s) and viscoelastic behaviour. UV irradiation of the surfactant solution creates a less dense micellar network, with some vesicle formation. As a result, the solution viscosity is reduced by four orders of magnitude (to 1.2 × 10−3 Pa s). This process is reversible and the high and low viscosity states can be cycled several times, through alternating UV and blue light irradiation.

Graphical abstract: A single-component photorheological fluid with light-responsive viscosity

Supplementary files

Article information

Article type
Paper
Submitted
06 Dec 2019
Accepted
05 Mar 2020
First published
12 Mar 2020

Nanoscale, 2020,12, 6300-6306

Author version available

A single-component photorheological fluid with light-responsive viscosity

E. A. Kelly, N. Willis-Fox, J. E. Houston, C. Blayo, G. Divitini, N. Cowieson, R. Daly and R. C. Evans, Nanoscale, 2020, 12, 6300 DOI: 10.1039/C9NR10350C

To request permission to reproduce material from this article, 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 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