Wetting Anomalies on Kaolin Particles Highlighting Limits of the Thin-Layer Washburn Technique
DOI:
https://doi.org/10.47451/che2025-11-01Keywords:
mural, public art, street art, urban environmentAbstract
The determination of surface free energy and wetting characteristics of powdered minerals remains a methodological challenge due to the inability to apply conventional contact-angle techniques to porous and highly absorbent materials. Kaolin is widely used as a model aluminosilicate system, yet its complex surface chemistry raises questions concerning the applicability of classical approaches such as the Washburn equation. The present study investigates the wetting behaviour of thin kaolin layers using water and cyclohexane, with the aim of evaluating deviations from Washburn-type capillary rise dynamics. A thin-layer wicking method was employed, combining controlled sample preparation, high-resolution video tracking, and statistical analysis of capillary kinetics. The work builds on established research by Chibowski, Newby, Danchenko, Rybka and others, who have highlighted both the utility and the limitations of the Washburn method for powders. The results show that the initial wetting front is strongly non-uniform and influenced by adsorption-driven and inertial effects, while subsequent stages reflect a transition to capillary-controlled motion accompanied by the formation of a diffuse partially saturated region. Despite this heterogeneity, repeated measurements demonstrated high reproducibility, yielding a consistent average capillary rise rate of approximately 4460 μm²/s for water. However, a pronounced divergence from theoretical predictions was observed: cyclohexane permeated the kaolin layer significantly faster than water, contradicting Washburn-based expectations derived from assumed contact angles. These findings indicate that the classical Washburn model does not adequately describe wetting in kaolin layers and suggest that additional factors — such as ionic interactions, partial pore saturation, or dissolved-gas effects — may govern the observed anomalies. The study thus defines clear limitations of the thin-layer Washburn technique and outlines directions for refining wetting analysis in complex mineral powders.
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Alghunaim, A., Kirdponpattara, S., & Newby, B. Z. (2015). Techniques for determining contact angle and wettability of powders. Powder Technology, 287, 201–215. https://doi.org/10.1016/j.powtec.2015.10.002
Benner, E. M., & Petsev, D. N. (2017). Evaporation effect on two-dimensional wicking in porous media. Journal of Colloid and Interface Science, 514, 21–29. https://doi.org/10.1016/j.jcis.2017.12.004
Chibowski, E., & Holysz, L. (1992). Use of the Washburn equation for surface free energy determination. Langmuir, 8(2), 710–716. https://doi.org/10.1021/la00038a066
Danchenko, Y., Andronov, V., Teslenko, M., Permiakov, V., Rybka, E., Meleshchenko, R., & Kosse, A. (2018). Study of the free surface energy of epoxy composites using an automated measurement system. Eastern-European Journal of Enterprise Technologies, 1(12(91)), 9–17. https://doi.org/10.15587/1729-4061.2018.120998
De Farias, E. C. C., Fermam, R. K. S., & De J Souza Marques De Mendonça, A. (2025). Comparison between the Wilhelmy surface tension measurement method and the pendant drop shape analysis method. Acta Polytechnica, 65(3), 276–281. https://doi.org/10.14311/ap.2025.65.0276
Kirdponpattara, S., Phisalaphong, M., & Newby, B. Z. (2013). Applicability of Washburn capillary rise for determining contact angles of powders/porous materials. Journal of Colloid and Interface Science, 397, 169–176. https://doi.org/10.1016/j.jcis.2013.01.033
Kwak, W., Park, J. K., Yoon, J., Lee, S., & Hwang, W. (2018). Measurement of surface tension by sessile drop tensiometer with superoleophobic surface. Applied Physics Letters, 112(12). https://doi.org/10.1063/1.5011439
Kwaśniewska, A., Chocyk, D., Gładyszewski, G., Borc, J., Świetlicki, M., & Gładyszewska, B. (2020). The influence of kaolin clay on the mechanical properties and structure of thermoplastic starch films. Polymers, 12(1), 73. https://doi.org/10.3390/polym12010073
Mampallil, D., Sharma, M., Sen, A., & Sinha, S. (2018). Beyond the coffee-ring effect: Pattern formation by wetting and spreading of drops. Physical Review. E, 98(4). https://doi.org/10.1103/physreve.98.043107
Myronyuk, O., Baklan, D., & Nudchenko, L. (2020). Evaluation of the surface energy of dispersed aluminium oxide using owens-wendt theory. Technology Audit and Production Reserves, 2(1(52)), 25–27. https://doi.org/10.15587/2312-8372.2020.200756
Tullis, B. P., & Wright, S. J. (2007). Wetting front instabilities: a three-dimensional experimental investigation. Transport in Porous Media, 70(3), 335–353. https://doi.org/10.1007/s11242-007-9103-x
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