employee
Penza State University (Department of Chemistry and methods of teaching chemistry, associate professor)
Penza, Russian Federation
The colloidal-chemical properties of Pickering emulsions based on SAE 5W-30 motor oil and hydrocracked transformer oil (GK), stabilized with hydrophobic silicon dioxide (Aerosil R972) in the presence of the nonionic surfactant polysorbate-60 (or Tween-60), were studied. Using stalagmometry with an ST-2 stalagmometer with a curved capillary, the effective interfacial tension at the oil/water interface was measured, and the surface tension of transformer oil at the oil/air interface was qualitatively estimated depending on the presence of aerosil particles. It was shown that the introduction of Aerosil R972 increases the effective interfacial tension at the oil/water interface by 4-21 mJ/m² due to the so-called "booking effect" - the mechanical resistance of a structured layer of particles to droplet detachment. Independent confirmation of this effect was obtained at the transformer oil/air interface, where the introduction of aerosil increases the displacement of the stalagmometer piston at the moment of bubble detachment by 80%. Using droplet profile analysis, the contact angles of aerosil particles with the oil phase and the aqueous phase were measured at different concentrations of Tween-60 for both oils. At a Tween-60 concentration of 0.09%, the contact angle is θ ≈ 85-92°, which corresponds to the maximum particle adsorption energy and optimal conditions for stabilizing a direct oil/water emulsion. Emulsions with optimal compositions maintain aggregation stability for at least two months without signs of separation. The dataset is interpreted within the framework of a model of competitive adsorption of particles and surfactant molecules, identifying three compositional regions with qualitatively different stabilization mechanisms.
PICKERING EMULSION, AEROSIL R972, POLYSORBATE-60, INTERFACIAL TENSION, CONTACT ANGLE, MOTOR OIL, TRANSFORMER OIL, ARMORING EFFECT, COMPETITIVE ADSORPTION
1. B.P. Binks, Langmuir, 33, 28, 6947–6963 (2017). DOI:https://doi.org/10.1021/acs.langmuir.7b00860.
2. Y. Chevalier, M.A. Bolzinger, Colloids Surf. A, 439, 23–34 (2013). DOI:https://doi.org/10.1016/j.colsurfa.2013.02.054.
3. A.V. Nushtaeva, N.G. Vilkova, Proceedings of Higher Educational Institutions of the Volga Region. Natural Sciences, 4 (20), 74–85 (2017).
4. G. Kaptay, Colloids Surf. A, 282–283, 387–401 (2006). DOI:https://doi.org/10.1016/j.colsurfa.2005.12.021.
5. A.V. Nushtaeva, Colloid J., 81, 4, 487-492 (2019). DOI:https://doi.org/10.1134/S0023291219040104.
6. A.O. Adilbekova, A.B. Ertaeva, Chemical Bulletin of Kazakh National University, 100, 1, 30–49 (2021).
7. M. Zanini, L. Isa, J. Phys.: Condens. Matter, 28 (31), Article 313002 (2016). DOI:https://doi.org/10.1088/0953-8984/28/31/313002.
8. M.Yu. Koroleva, D.A. Bydanov, E.V. Yurtov, Russian Colloid Journal, 81, 1, 61–69 (2019). DOI:https://doi.org/10.1134/S0023291219010087.
9. B.P. Binks, J.A. Rodrigues, Colloids Surf. A, 345, 1-3, 195–201 (2009). DOI:https://doi.org/10.1016/j.colsurfa.2009.05.001.
10. T.S. Horozov, B.P. Binks, Angew. Chem. Int. Ed., 45, 5, 773–776 (2006). DOI:https://doi.org/10.1002/anie.200503131.
11. F. Gautier, M. Destribats, R. Perrier-Cornet, J. Dechézelles, J. Giermanska, V. Héroguez, S. Ravaine, F. Leal-Calderon, V. Schmitt, Phys. Chem. Chem. Phys., 9, 48, 6455–6462 (2007). DOI:https://doi.org/10.1039/b710226g.
12. N.G. Vilkova, S.I. Mishina, E.D. Deputatov, Khim. Khim. Tekhnol., 63, 3, 23–29 (2020). DOI:https://doi.org/10.6060/ivkkt.20206303.6126.
13. A. Bensadok, S. Benammar, F. Lapicque, G. Nezzal, J. Hazard. Mater., 152, 1, 423–430 (2008). DOI:https://doi.org/10.1016/j.jhazmat.2007.06.121.
14. E. Guzman, F. Ortega, R.G. Rubio, Cosmetics, 9, 4, Article 68 (2022). DOI:https://doi.org/10.3390/cosmetics9040068.
15. D. Zangh, A. Lee, Food Hydrocoll., 131, Article 107803 (2022). DOI:https://doi.org/10.1016/j.foodhyd.2022.107803
