Surface Properties of Saponin—Chitosan Mixtures
The surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that saponin-chitosan mixtures present some remarkab...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-11-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/21/7505 |
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| author | Marcel Krzan Natalia García Rey Ewelina Jarek Agnieszka Czakaj Eva Santini Francesca Ravera Libero Liggieri Piotr Warszynski Björn Braunschweig |
| author_facet | Marcel Krzan Natalia García Rey Ewelina Jarek Agnieszka Czakaj Eva Santini Francesca Ravera Libero Liggieri Piotr Warszynski Björn Braunschweig |
| author_sort | Marcel Krzan |
| collection | DOAJ |
| description | The surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that saponin-chitosan mixtures present some remarkable properties, such as a strong amphiphilicity of the saponin and high dilational viscoelasticity. We believe this points to the presence of chitosan in the adsorption layer, despite its complete lack of surface activity. We explain this phenomenon by electrostatic interactions between the saponin as an anionic surfactant and chitosan as a polycation, leading to surface-active saponin-chitosan complexes and aggregates. Analysing the SFG intensity of the O-H stretching bands from interfacial water molecules, we found that in the case of pH 3.4 for a mixture consisting of 0.1 g/L saponin and 0.001 g/L chitosan, the adsorption layer was electrically neutral. This conclusion from SFG spectra is corroborated by results from surface tensiometry showing a significant reduction in surface tension and effects on the dilational surface elasticity strictly at saponin/chitosan ratios, where SFG spectra indicate zero net charge at the air–water interface. |
| first_indexed | 2024-03-09T18:48:14Z |
| format | Article |
| id | doaj.art-b055f3eafab04117b446c26975ac5050 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T18:48:14Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-b055f3eafab04117b446c26975ac50502023-11-24T06:05:22ZengMDPI AGMolecules1420-30492022-11-012721750510.3390/molecules27217505Surface Properties of Saponin—Chitosan MixturesMarcel Krzan0Natalia García Rey1Ewelina Jarek2Agnieszka Czakaj3Eva Santini4Francesca Ravera5Libero Liggieri6Piotr Warszynski7Björn Braunschweig8Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Krakow, PolandInstitute of Physical Chemistry and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, GermanyJerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Krakow, PolandJerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Krakow, PolandInstitute of Condensed Matter and Technologies for Energy, Consiglio Nazionale delle Ricerche, Via Marini 6, 16149 Genova, ItalyInstitute of Condensed Matter and Technologies for Energy, Consiglio Nazionale delle Ricerche, Via Marini 6, 16149 Genova, ItalyInstitute of Condensed Matter and Technologies for Energy, Consiglio Nazionale delle Ricerche, Via Marini 6, 16149 Genova, ItalyJerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Krakow, PolandInstitute of Physical Chemistry and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, GermanyThe surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that saponin-chitosan mixtures present some remarkable properties, such as a strong amphiphilicity of the saponin and high dilational viscoelasticity. We believe this points to the presence of chitosan in the adsorption layer, despite its complete lack of surface activity. We explain this phenomenon by electrostatic interactions between the saponin as an anionic surfactant and chitosan as a polycation, leading to surface-active saponin-chitosan complexes and aggregates. Analysing the SFG intensity of the O-H stretching bands from interfacial water molecules, we found that in the case of pH 3.4 for a mixture consisting of 0.1 g/L saponin and 0.001 g/L chitosan, the adsorption layer was electrically neutral. This conclusion from SFG spectra is corroborated by results from surface tensiometry showing a significant reduction in surface tension and effects on the dilational surface elasticity strictly at saponin/chitosan ratios, where SFG spectra indicate zero net charge at the air–water interface.https://www.mdpi.com/1420-3049/27/21/7505saponinchitosansaponin—chitosan interactionsbio-compatible systemsbiodegradable surfactants |
| spellingShingle | Marcel Krzan Natalia García Rey Ewelina Jarek Agnieszka Czakaj Eva Santini Francesca Ravera Libero Liggieri Piotr Warszynski Björn Braunschweig Surface Properties of Saponin—Chitosan Mixtures Molecules saponin chitosan saponin—chitosan interactions bio-compatible systems biodegradable surfactants |
| title | Surface Properties of Saponin—Chitosan Mixtures |
| title_full | Surface Properties of Saponin—Chitosan Mixtures |
| title_fullStr | Surface Properties of Saponin—Chitosan Mixtures |
| title_full_unstemmed | Surface Properties of Saponin—Chitosan Mixtures |
| title_short | Surface Properties of Saponin—Chitosan Mixtures |
| title_sort | surface properties of saponin chitosan mixtures |
| topic | saponin chitosan saponin—chitosan interactions bio-compatible systems biodegradable surfactants |
| url | https://www.mdpi.com/1420-3049/27/21/7505 |
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