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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| Format: | Article |
| Language: | English |
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MDPI AG
2021-06-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/26/13/3946 |
| _version_ | 1797411526217302016 |
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| author | Rui A. Gonçalves Yeng-Ming Lam Björn Lindman |
| author_facet | Rui A. Gonçalves Yeng-Ming Lam Björn Lindman |
| author_sort | Rui A. Gonçalves |
| collection | DOAJ |
| description | 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, L<sub>β</sub> and L<sub>α</sub>, 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 L<sub>α</sub> phase was found to have a bilayer structure, generally found for most surfactants; a L<sub>β</sub> 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, L<sub>β</sub> and L<sub>α</sub> 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 L<sub>β</sub>–L<sub>α</sub> transition, we identified the possibility of a triggered phase transition via dilution with water. |
| first_indexed | 2024-03-09T04:47:23Z |
| format | Article |
| id | doaj.art-e1c9c9ed6dc74e968e35a7afc58bd7a0 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T04:47:23Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-e1c9c9ed6dc74e968e35a7afc58bd7a02023-12-03T13:14:50ZengMDPI AGMolecules1420-30492021-06-012613394610.3390/molecules26133946Double-Chain Cationic Surfactants: Swelling, Structure, Phase Transitions and Additive EffectsRui A. Gonçalves0Yeng-Ming Lam1Björn Lindman2School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, SingaporeSchool of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, SingaporeSchool of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, SingaporeDouble-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, L<sub>β</sub> and L<sub>α</sub>, 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 L<sub>α</sub> phase was found to have a bilayer structure, generally found for most surfactants; a L<sub>β</sub> 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, L<sub>β</sub> and L<sub>α</sub> 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 L<sub>β</sub>–L<sub>α</sub> transition, we identified the possibility of a triggered phase transition via dilution with water.https://www.mdpi.com/1420-3049/26/13/3946double-chain surfactantlamellar gellamellar liquid crystalhair conditionersurfactant packingadditive effects |
| spellingShingle | Rui A. Gonçalves Yeng-Ming Lam Björn Lindman Double-Chain Cationic Surfactants: Swelling, Structure, Phase Transitions and Additive Effects Molecules double-chain surfactant lamellar gel lamellar liquid crystal hair conditioner surfactant packing additive effects |
| title | 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_short | Double-Chain Cationic Surfactants: Swelling, Structure, Phase Transitions and Additive Effects |
| title_sort | double chain cationic surfactants swelling structure phase transitions and additive effects |
| topic | double-chain surfactant lamellar gel lamellar liquid crystal hair conditioner surfactant packing additive effects |
| url | https://www.mdpi.com/1420-3049/26/13/3946 |
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