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Title: Photoresponsive gelators
Author: Draper, E. R.
ISNI:       0000 0004 6350 8709
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2016
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We describe the synthesis of new low molecular weight gelators based on three different photoresponsive molecules functionalised with amino acids or dipeptides. Photoresponsive gels are interesting from the perspective of patterning. The gelation ability of the new gelators is explored using different methods two different methods of changing the pH. The photoresponse of these gels is investigated and the rheological properties measured to determine how the gel has changed. A coumarin based dipeptide gel is formed electrochemically and by GdL. By using UV light, the dimer of the coumarin is formed in the gel and in solution, which is then investigated. Interestingly, this gel is an extremely rare example where the strength of the gel increases on irradiation. Most others examples become a solution when irradiated. The gelation of a stilbene-based gelator is carried out using GdL. Upon UV irradiation, stilbene isomerises from trans to cis. This is examined in both the gel and the solution. The stilbene molecule is then used as part of a multi-component system to investigate self-assembly or co-assembly of different molecules upon gelation. This system allows us to prove that the second network is completely independent of the self-assembled stilbene network, which is the first time that this has been proven. A series of gelators based on perylene bisimides are synthesised and the assembly of the gelators in solution and the gel are investigated. The two systems are dried down between two electrodes to monitor the change in electronic properties when irradiated with light. We have then aligned these materials to give better conductive properties. The perylene thin films are further examined with the properties of the films being measured in the presence of different hole scavengers. The perylene and stilbene gelators are then used in a multi-component gelator systems, and again the self-assembly or co-assembly is explored. The two-components are gelled in different ratios to each other and the conductive response under light again is investigated to see whether they could be used as a p-n heterojunction material. We show that the stilbene is able to act as a hole scavenger and affect the wavelength at which the photoconductivity is most effective. This provides evidence that we have managed to prepare two networks that are able to interact with one another, and hence are likely to effective as a bulk heterojunction.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available