Document Type : Research Paper


1 Associate Professor, Aerospace Research Institute, Ministry of Science, Research and Technology, Tehran, Iran

2 Professor, Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran

3 Ph.D., Student, Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran

4 Professor, Max Planck Institute of Colloids and Interfaces, Germany


Superhydrophobic coatings can be made by creating a micro-sized structure on a surface providing super-repellent properties which has many applications in aerospace, defense, automotive, biomedical and engineering. Numerical simulation of drop dynamics and motion on a superhydrophobic surface helps us understand control and building surface textures and find optimum micro structured coatings of maximum hydrophobicity. In the present work, the dynamics of drops on superhydrophobic inclined micro-structured surfaces is studied, using a finite element method. Effect of microstructures on droplet behavior on a superhydrophobic surface is investigated using different microstructures. The governing equations and important dimensionless numbers are described and a numerical algorithm is introduced. The validation of the numerical algorithm is performed by simulation of drop motion attached to an inclined surface. In addition, droplet movement on the micro structured surface is numerically simulated on smooth and microstructure surfaces in the same conditions. Comparison of the results shows the effect of microstructure coating on the surface hydrophobicity properties.


Main Subjects

[1] K. Manoharan and S. Bhattacharya1, “Superhydrophobic surfaces review: Functional application, fabrication techniques and limitations”, Journal of Micromanufacturing, vol. 2, no. 1, pp. 59–78, 2019.
[2]  S. Dey and B. Giri, “luoride fact on human health and health problems: a review”, Med Clin Rev 2016; vol.2, no. 1, pp.1–6, 2016.
[3] F.H. Rajab, Z. Liu and L. Li, “Long term superhydrophobic and hybrid superhydrophobic/superhydrophilic surfaces produced by laser surface micro/nano surface structuring”, Appl Surf Sci, vol. 466, pp. 808–821, 2019.
[4] P. Pou, J. Del Val, A. Riveiro, “Laser texturing of stainless steel under different processing atmospheres: from superhydrophilic to superhydrophobic surfaces”, Appl Surf Sci2019, vol. 475, pp. 896–905, 2019.
[5] D. Huerta-Murillo, A. García-Girón, J.M. Romano, ”Wettability modification of laser-fabricated hierarchical surface structures in Ti-6Al-4V titanium alloy” Appl Surf Sci 2019, vol. 463, pp. 838–846, 2019.
[6] P. Wang, X. Qian and J. Shen, “Superhydrophobic coatings with edible biowaxes for reducing or eliminating liquid residues of foods and drinks in containers”, Bioresources 2018, vol. 13, no. 1, pp. 1–2., 2018.
[7] Z. Y. Deng, W. Wang, L. H. Mao, C. F. Wang and S. Chen, “Versatile Superhydrophobic and Photocatalytic Films Generated from TiO2–SiO2 at PDMS and Their Applications on Fabrics”, J. Mater. Chem. A, vol. 2, pp. 4178–4184, 2014.
[8] L. F. Que, Z. Lan, W. X. Wu, J. H. Wu, J. M. Lin and M. L. Huang, “High-efficiency Dye-sensitized Solar Cells Based on Ultra-long Single Crystalline Titanium Dioxide Nanowires”, J. Power Sources, vol. 266, pp. 440–447, 2014.
[9] Z. Liu, Y. Gou, J. Wang, and S. Cheng, “Frost Formation on a Super-hydrophobic Surface under Natural Convection Conditions”, International Journal of Heat and Mass Transfer, vol. 51, pp. 5975–5982, 2008.
[10] M. He, J. Wang, H. Li, X. Jin, J. Wang, B. Liu, and Y. Song, “Super-hydrophobic Film Retards Frost Formation”, Soft Matter, vol. 6, pp. 2396–2399, 2010.
[11] L. Mishchenko, B. Hatton, V. Bahadur, J. A. Taylor, T. Krupenkin, and J. Aizenberg, “Design of Ice-free Nanostructured Surfaces Based on Repulsion of Impacting Water Droplets”, ACS Nano, vol. 4, pp. 7699–7707, 2010.
[12] K. Javadi, S. H. Davoudian, "Surface Wettability Effect on the Rising of a Bubble Attached to a Vertical Wall", IJMPF, Elsevier, vol. 109, pp. 178-190, 2018.
[13] T. Nishino, M. Meguro, K. Nakamae, M. Matsushita and Y. Ueda, “The Lowest Surface Free Energy Based on −CF3 Alignment”, Langmuir, vol. 15, pp. 4321–4323, 1999.
[14] R. Kamali Moghadam1, M. Taeibi Rahni, Kh. Javadi, S. Heyat Davoudian, R. Miller, “Influence of New Superhydrophobic Micro-structures on Delaying Ice Formation”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 595, 2020.
[15] G. Zhu, J. Yao, L. Zhang, H. Sun, A. Li, and B. Shams, “Investigation of the Dynamic Contact Angle Using a Direct Numerical Simulation Method”, Langmuir, vol. 32, pp. 1736−11744, 2016.
[16] H. Jia, X. Xiao, Y. Kang, “Investigation of a free rising bubble with mass transfer by an arbitrary Lagrangian–Eulerian method”, International Journal of Heat and Mass Transfer, vol. 137, pp. 545–557, 2019.
[17] S. McKee, M. F. Tome, V. G. Ferreira, J. A. Cuminato, A. Castelo, F. S. Sousa, N. Mangiavacchi, “The MAC method”, Computers & Fluids, vol. 37, pp. 907–930, 2008.
[18] P. Yue, C. Zhou, J. J. Feng, C. F. Ollivier-Gooch, H. H. Hu, “Phase-field simulations of interfacial dynamics in viscoelastic fluids using finite elements with adaptive meshing”, J. Comput. Phys, vol. 219, pp. 47–67, 2006.
[19] M. van Sint Annaland, N. G. Deen, J. A. M. Kuipers, “Numerical simulation of gas bubbles behaviour using a three-dimensional volume of fluid method”, Chem. Eng. Sci. vol. 60, pp. 2999–3011, 2005.
[20] Y. Tanaka, Y. Washio, M. Yoshino, T. Hirata, “Numerical simulation of dynamic behavior of droplet on solid surface by the two-phase lattice Boltzmann method”, Computers & Fluids, vol. 40, 68–78, 2011.
[21] P. Tourkine, M. Le Merrer, and D. Quere, “Delayed Freezing on Water Repellent Materials”, Langmuir, vol. 25, pp. 7214–7216, 2009.
[22] G. Zhu, J. Yao, L. Zhang, H. Sun, A. Li, and B. Shams, “Investigation of the Dynamic Contact Angle Using a Direct Numerical Simulation Method”, Langmuir, vol. 32, pp. 1736−11744, 2016.
[23] R. Clift, J. R. Grace, and M. E. Weber, Bubbles, Drops, and Particles, Academic Press, 1978.
[24] H-Y. Kim, H. J. Lee, and B. H. Kang, “Sliding of Liquid Drops Down an Inclined Solid Surface”, Journal of Colloid and Interface Science, vol. 247, pp. 372–380, 2002