Using solution history to control hydrogel properties of a perylene bisimide

Ginesi, R. E., Murray, N. R., Dalgliesh, R., Doutch, J. and Draper, E. R. (2023) Using solution history to control hydrogel properties of a perylene bisimide. Chemistry: A European Journal, 29(37), e202301042. (doi: 10.1002/chem.202301042) (PMID:37067953)

Abstract

pH dependence on water soluble aggregates is well-known in the field of low molecular weight gelators (LMWGs), with different aggregates sometimes having very different properties depending on their final pH. This aggregation determines their applications and performance. Here, we investigate the pH dependence of perylene bisimide gels; initially solutions are formed at a high pH and gels form as the pH is decreased. We find it is not only the final pH but also the starting pH that can impact the resulting gel. We use small angle neutron scattering (SANS), rheology, 1H NMR spectroscopy and absorption spectroscopy to examine the effect of starting pH on gelation kinetics and final gel properties. Adjusting the solution from pH 9 (where there are few or no aggregates) to pH 6 results in the formation of different worm-like micelles than the ones directly formed at pH 6, leading to again gels with different mechanical properties. This work highlights the importance of controlling the pH of solutions before gelation, but also opens up more possible morphologies and therefore more properties from the same molecule.

• Item Type: Articles
• Additional Information: The authors would like to thank the EPSRC (EP/S032673/1) and (EP/R513222/1), and the UKRI (MR/V021087/1) for funding. We acknowledge beamtime allocation at ISIS neutron Muon and Neutron Source, Rutherford Appleton Laboratories, Didcot, UK (experiment number RB2210011 and RB2220192). This work benefitted from 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 Ginesi, Miss Rebecca and Murray, Mr Nicholas
• Authors: Ginesi, R. E., Murray, N. R., Dalgliesh, R., Doutch, J., and Draper, E. R.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Chemistry: A European Journal
• Publisher: Wiley
• ISSN: 0947-6539
• ISSN (Online): 1521-3765
• Published Online: 17 April 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Chemistry: A European Journal 29(37):e202301042
• Publisher Policy: Reproduced under a Creative Commons license

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
306112		Electrochromic Gels for Smart Windows	Emily Draper	Engineering and Physical Sciences Research Council (EPSRC)	EP/S032673/1	Chemistry
305200		DTP 2018-19 University of Glasgow	Mary Beth Kneafsey	Engineering and Physical Sciences Research Council (EPSRC)	EP/R513222/1	MVLS - Graduate School