Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid Solutions
The colloidal stability of sulfate (SL) and polyimidazolium-modified sulfate (SL-IP-2) latex particles was studied in an ionic liquid (IL) of ethylammonium nitrate (EAN) and its water mixtures. Aggregation rates were found to vary systematically as a function of the IL-to-water ratio. Repulsive elec...
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MDPI AG
2021-12-01
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| Series: | Colloids and Interfaces |
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| Online Access: | https://www.mdpi.com/2504-5377/6/1/2 |
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| author | Dóra Takács Matija Tomšič Istvan Szilagyi |
| author_facet | Dóra Takács Matija Tomšič Istvan Szilagyi |
| author_sort | Dóra Takács |
| collection | DOAJ |
| description | The colloidal stability of sulfate (SL) and polyimidazolium-modified sulfate (SL-IP-2) latex particles was studied in an ionic liquid (IL) of ethylammonium nitrate (EAN) and its water mixtures. Aggregation rates were found to vary systematically as a function of the IL-to-water ratio. Repulsive electrostatic interactions between particles dominated at low IL concentrations, while they were significantly screened at intermediate IL concentrations, leading to destabilization of the dispersions. When the IL concentration was further increased, the aggregation of latex particles slowed down due to the increased viscosity and finally, a striking stabilization was observed in the IL-rich regime close to the pure IL solvent. The latter stabilization is due to the formation of IL layers at the interface between particles and IL, which induce repulsive oscillatory forces. The presence of the added salt in the system affected differently the structure of the interfaces around SL and SL-IP-2 particles. The sign of the charge and the composition of the particle surfaces were found to be the most important parameters affecting the colloidal stability. The nature of the counterions also plays an important role in the interfacial properties due to their influence on the structure of the IL surface layers. No evidence was observed for the presence of long-range electrostatic interactions between the particles in pure ILs. The results indicate that the presence of even low concentrations of water and salt in the system (as undesirable impurities) can strongly alter the interfacial structure and thus, the aggregation mechanism in particle IL dispersions. |
| first_indexed | 2024-03-09T19:58:36Z |
| format | Article |
| id | doaj.art-0127c1042e1041c8b9f6fbef8c5f40b5 |
| institution | Directory Open Access Journal |
| issn | 2504-5377 |
| language | English |
| last_indexed | 2024-03-09T19:58:36Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Colloids and Interfaces |
| spelling | doaj.art-0127c1042e1041c8b9f6fbef8c5f40b52023-11-24T00:49:44ZengMDPI AGColloids and Interfaces2504-53772021-12-0161210.3390/colloids6010002Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid SolutionsDóra Takács0Matija Tomšič1Istvan Szilagyi2MTA-SZTE Lendület Biocolloids Research Group, Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, H-6720 Szeged, HungaryFaculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, SloveniaMTA-SZTE Lendület Biocolloids Research Group, Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, H-6720 Szeged, HungaryThe colloidal stability of sulfate (SL) and polyimidazolium-modified sulfate (SL-IP-2) latex particles was studied in an ionic liquid (IL) of ethylammonium nitrate (EAN) and its water mixtures. Aggregation rates were found to vary systematically as a function of the IL-to-water ratio. Repulsive electrostatic interactions between particles dominated at low IL concentrations, while they were significantly screened at intermediate IL concentrations, leading to destabilization of the dispersions. When the IL concentration was further increased, the aggregation of latex particles slowed down due to the increased viscosity and finally, a striking stabilization was observed in the IL-rich regime close to the pure IL solvent. The latter stabilization is due to the formation of IL layers at the interface between particles and IL, which induce repulsive oscillatory forces. The presence of the added salt in the system affected differently the structure of the interfaces around SL and SL-IP-2 particles. The sign of the charge and the composition of the particle surfaces were found to be the most important parameters affecting the colloidal stability. The nature of the counterions also plays an important role in the interfacial properties due to their influence on the structure of the IL surface layers. No evidence was observed for the presence of long-range electrostatic interactions between the particles in pure ILs. The results indicate that the presence of even low concentrations of water and salt in the system (as undesirable impurities) can strongly alter the interfacial structure and thus, the aggregation mechanism in particle IL dispersions.https://www.mdpi.com/2504-5377/6/1/2ionic liquidaggregationlatex particlelight scatteringcolloidal stability |
| spellingShingle | Dóra Takács Matija Tomšič Istvan Szilagyi Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid Solutions Colloids and Interfaces ionic liquid aggregation latex particle light scattering colloidal stability |
| title | Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid Solutions |
| title_full | Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid Solutions |
| title_fullStr | Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid Solutions |
| title_full_unstemmed | Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid Solutions |
| title_short | Effect of Water and Salt on the Colloidal Stability of Latex Particles in Ionic Liquid Solutions |
| title_sort | effect of water and salt on the colloidal stability of latex particles in ionic liquid solutions |
| topic | ionic liquid aggregation latex particle light scattering colloidal stability |
| url | https://www.mdpi.com/2504-5377/6/1/2 |
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