Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system
We report new dirhamnolipid ester forming reverse wormlike micelles in nonpolar solvents without the addition of any primer. Therefore, these compounds represent a rare case of a binary system showing this gel-like behavior. In this study, the influence of the concentration of the rhamnolipid ester...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Beilstein-Institut
2020-11-01
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| Series: | Beilstein Journal of Organic Chemistry |
| Subjects: | |
| Online Access: | https://doi.org/10.3762/bjoc.16.232 |
| _version_ | 1818719298378530816 |
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| author | David Liese Hans Henning Wenk Xin Lu Jochen Kleinen Gebhard Haberhauer |
| author_facet | David Liese Hans Henning Wenk Xin Lu Jochen Kleinen Gebhard Haberhauer |
| author_sort | David Liese |
| collection | DOAJ |
| description | We report new dirhamnolipid ester forming reverse wormlike micelles in nonpolar solvents without the addition of any primer. Therefore, these compounds represent a rare case of a binary system showing this gel-like behavior. In this study, the influence of the concentration of the rhamnolipid ester and the ester alkyl chain length on the rheological properties of the reverse wormlike micelles in toluene was investigated in detail. Highly viscoelastic solutions were obtained even at a relatively low concentration of less than 1 wt %. The phase transition temperatures indicate that the formation of reverse wormlike micelles is favored for dirhamnolipid esters with shorter alkyl chain lengths. Oscillatory shear measurements for the viscoelastic samples reveal that the storage modulus (G') and the loss modulus (G'') cross each other and fit the Maxwell model very well in the low-ω region. As is typical for wormlike micelle systems, the normalized Cole–Cole plot of G''/G''max against G'/G''max was obtained as a semicircle centered at G'/G''max = 1. The formation of network structures was also verified by polarized light microscopy. The sample was birefringent at ambient temperature and anisotropic at an elevated temperature. Differential scanning calorimetry analysis yielded a transition enthalpy of about ΔHSG/GS = ±7.2 kJ/mol. This value corresponds to a strong dispersion energy and explains the formation of the highly viscous gels by the entanglement of wormlike micelles through the interaction of the alkyl chains. |
| first_indexed | 2024-12-17T20:04:43Z |
| format | Article |
| id | doaj.art-cf00e70a649c40488ff2abbeeca84b50 |
| institution | Directory Open Access Journal |
| issn | 1860-5397 |
| language | English |
| last_indexed | 2024-12-17T20:04:43Z |
| publishDate | 2020-11-01 |
| publisher | Beilstein-Institut |
| record_format | Article |
| series | Beilstein Journal of Organic Chemistry |
| spelling | doaj.art-cf00e70a649c40488ff2abbeeca84b502022-12-21T21:34:21ZengBeilstein-InstitutBeilstein Journal of Organic Chemistry1860-53972020-11-011612820283010.3762/bjoc.16.2321860-5397-16-232Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) systemDavid Liese0Hans Henning Wenk1Xin Lu2Jochen Kleinen3Gebhard Haberhauer4Institut für Organische Chemie, Universität Duisburg-Essen, Universitätsstraße 7, D-45117 Essen, GermanyEvonik Operations GmbH, Evonik Industries AG, Goldschmidtstraße 100, D-45139 Essen, GermanyEvonik Operations GmbH, Evonik Industries AG, Goldschmidtstraße 100, D-45139 Essen, GermanyEvonik Operations GmbH, Evonik Industries AG, Goldschmidtstraße 100, D-45139 Essen, GermanyInstitut für Organische Chemie, Universität Duisburg-Essen, Universitätsstraße 7, D-45117 Essen, GermanyWe report new dirhamnolipid ester forming reverse wormlike micelles in nonpolar solvents without the addition of any primer. Therefore, these compounds represent a rare case of a binary system showing this gel-like behavior. In this study, the influence of the concentration of the rhamnolipid ester and the ester alkyl chain length on the rheological properties of the reverse wormlike micelles in toluene was investigated in detail. Highly viscoelastic solutions were obtained even at a relatively low concentration of less than 1 wt %. The phase transition temperatures indicate that the formation of reverse wormlike micelles is favored for dirhamnolipid esters with shorter alkyl chain lengths. Oscillatory shear measurements for the viscoelastic samples reveal that the storage modulus (G') and the loss modulus (G'') cross each other and fit the Maxwell model very well in the low-ω region. As is typical for wormlike micelle systems, the normalized Cole–Cole plot of G''/G''max against G'/G''max was obtained as a semicircle centered at G'/G''max = 1. The formation of network structures was also verified by polarized light microscopy. The sample was birefringent at ambient temperature and anisotropic at an elevated temperature. Differential scanning calorimetry analysis yielded a transition enthalpy of about ΔHSG/GS = ±7.2 kJ/mol. This value corresponds to a strong dispersion energy and explains the formation of the highly viscous gels by the entanglement of wormlike micelles through the interaction of the alkyl chains.https://doi.org/10.3762/bjoc.16.232dirhamnolipid estergemini surfactantrheologyreverse wormlike micelle (rwlm) |
| spellingShingle | David Liese Hans Henning Wenk Xin Lu Jochen Kleinen Gebhard Haberhauer Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system Beilstein Journal of Organic Chemistry dirhamnolipid ester gemini surfactant rheology reverse wormlike micelle (rwlm) |
| title | Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system |
| title_full | Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system |
| title_fullStr | Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system |
| title_full_unstemmed | Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system |
| title_short | Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system |
| title_sort | dirhamnolipid ester formation of reverse wormlike micelles in a binary primerless system |
| topic | dirhamnolipid ester gemini surfactant rheology reverse wormlike micelle (rwlm) |
| url | https://doi.org/10.3762/bjoc.16.232 |
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