Reversible photoreduction as a trigger for photoresponsive gels

Draper, E. R. , Schweins, R., Akhtar, R., Groves, P., Chechik, V., Zwijnenburg, M. A. and Adams, D. J. (2016) Reversible photoreduction as a trigger for photoresponsive gels. Chemistry of Materials, 28(17), pp. 6336-6341. (doi: 10.1021/acs.chemmater.6b02677)

Abstract

We present here a new type of photoresponsive, reversible low molecular weight gel. All previous examples rely on a photoisomerisation, ring-closing or dimerization. We show that photoreduction of a perylene bisimide gelator results in the formation of a stable radical anion. The formation of the radical anion results in a change in the packing of the perylene bisimides in the self-assembled aggregates, leading to a change in fibrous network and an increase in the rheological properties of the gels. An increase in the rheological properties is extremely rare for a photoresponsive gel; normally, irradiation results in a gel-to-sol transition, and the gel falling apart. As the radical anion decays, which takes several hours in air, the original gel properties are restored. This photoreduction can be cycled many times. Finally, we show that the mechanical properties are different between irradiated and nonirradiated sections in a patterned gel.

• Item Type: Articles
• Additional Information: E.D. thanks the EPSRC for funding (EP/L021978/1). M.Z. and D.A. thank the EPSRC for Fellowships (EP/I004424/1 and EP/L021978/1 respectively). The experiment at the Institut Laue Langevin was allocated beam time under experiment number 9-11-1756. This work benefitted from the SasView software, originally developed by the DANSE project under NSF award DMR-0520547.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Draper, Emily and Adams, Dave
• Authors: Draper, E. R., Schweins, R., Akhtar, R., Groves, P., Chechik, V., Zwijnenburg, M. A., and Adams, D. J.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Chemistry of Materials
• Publisher: American Chemical Society
• ISSN: 0897-4756
• ISSN (Online): 1520-5002
• Published Online: 23 August 2016
• Copyright Holders: Copyright © 2016 American Chemical Societ
• First Published: First published in Chemistry of Materials 28(17): 6336-6341
• Publisher Policy: Reproduced under a Creative Commons license