Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects
Double-chain amphiphilic compounds, including surfactants and lipids, have broad significance in applications like personal care and biology. A study on the phase structures and their transitions focusing on dioctadecyldimethylammonium chloride (DODAC), used inter alia in hair conditioners, is prese...
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sg-ntu-dr.10356-1538872023-07-14T16:05:35Z Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects Gonçalves, Rui A. Lam, Yeng Ming Lindman, Björn School of Materials Science and Engineering Engineering::Materials Double-Chain Surfactant Lamellar Gel Double-chain amphiphilic compounds, including surfactants and lipids, have broad significance in applications like personal care and biology. A study on the phase structures and their transitions focusing on dioctadecyldimethylammonium chloride (DODAC), used inter alia in hair conditioners, is presented. The phase behaviour is dominated by two bilayer lamellar phases, Lβ and Lα, with "solid" and "melted" alkyl chains, respectively. In particular, the study is focused on the effect of additives of different polarity on the phase transitions and structures. The main techniques used for investigation were differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS and WAXS). From the WAXS reflections, the distance between the alkyl chains in the bilayers was obtained, and from SAXS, the thicknesses of the surfactant and water layers. The Lα phase was found to have a bilayer structure, generally found for most surfactants; a Lβ phase made up of bilayers with considerable chain tilting and interdigitation was also identified. Depending mainly on the polarity of the additives, their effects on the phase stabilities and structure vary. Compounds like urea have no significant effect, while fatty acids and fatty alcohols have significant effects, but which are quite different depending on the nonpolar part. In most cases, Lβ and Lα phases exist over wide composition ranges; certain additives induce transitions to other phases, which include cubic, reversed hexagonal liquid crystals and bicontinuous liquid phases. For a system containing additives, which induce a significant lowering of the Lβ-Lα transition, we identified the possibility of a triggered phase transition via dilution with water. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Published version This research was funded by Procter & Gamble and Agency for Science, Technology and Research (A*STAR), Singapore (APG2013/016), Singapore Ministry of Education Academic Research Fund Tier 1 (2019-T1-002-35), and the Fundação para a Ciência e a Tecnologia (FCT), the Portuguese Agency for Scientific Research, through the Project UID/QUI/00313/2020, assigned to the Coimbra Chemistry Centre (CQC). 2022-06-03T02:56:20Z 2022-06-03T02:56:20Z 2021 Journal Article Gonçalves, R. A., Lam, Y. M. & Lindman, B. (2021). Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects. Molecules, 26(13), 3946-. https://dx.doi.org/10.3390/molecules26133946 1420-3049 https://hdl.handle.net/10356/153887 10.3390/molecules26133946 34203337 2-s2.0-85109571612 13 26 3946 en APG2013/016 2019-T1-002-35 Molecules © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). application/pdf |
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Engineering::Materials Double-Chain Surfactant Lamellar Gel Gonçalves, Rui A. Lam, Yeng Ming Lindman, Björn Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects |
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Double-chain amphiphilic compounds, including surfactants and lipids, have broad significance in applications like personal care and biology. A study on the phase structures and their transitions focusing on dioctadecyldimethylammonium chloride (DODAC), used inter alia in hair conditioners, is presented. The phase behaviour is dominated by two bilayer lamellar phases, Lβ and Lα, with "solid" and "melted" alkyl chains, respectively. In particular, the study is focused on the effect of additives of different polarity on the phase transitions and structures. The main techniques used for investigation were differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS and WAXS). From the WAXS reflections, the distance between the alkyl chains in the bilayers was obtained, and from SAXS, the thicknesses of the surfactant and water layers. The Lα phase was found to have a bilayer structure, generally found for most surfactants; a Lβ phase made up of bilayers with considerable chain tilting and interdigitation was also identified. Depending mainly on the polarity of the additives, their effects on the phase stabilities and structure vary. Compounds like urea have no significant effect, while fatty acids and fatty alcohols have significant effects, but which are quite different depending on the nonpolar part. In most cases, Lβ and Lα phases exist over wide composition ranges; certain additives induce transitions to other phases, which include cubic, reversed hexagonal liquid crystals and bicontinuous liquid phases. For a system containing additives, which induce a significant lowering of the Lβ-Lα transition, we identified the possibility of a triggered phase transition via dilution with water. |
author2 |
School of Materials Science and Engineering |
author_facet |
School of Materials Science and Engineering Gonçalves, Rui A. Lam, Yeng Ming Lindman, Björn |
format |
Article |
author |
Gonçalves, Rui A. Lam, Yeng Ming Lindman, Björn |
author_sort |
Gonçalves, Rui A. |
title |
Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects |
title_short |
Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects |
title_full |
Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects |
title_fullStr |
Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects |
title_full_unstemmed |
Double-chain cationic surfactants: swelling, structure, phase transitions and additive effects |
title_sort |
double-chain cationic surfactants: swelling, structure, phase transitions and additive effects |
publishDate |
2022 |
url |
https://hdl.handle.net/10356/153887 |
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1773551239380860928 |