Original Articles Open access

Motion behavior of a charged droplet impacting on hydrophilic and hydrophobic leaf surfaces

Authors

  • Wei Hu – articles in this journal Corresponding author Email School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu, China.
  • Zhouming Gao – articles in this journal School of Agricultural Engineering, Jiangsu University, Zhenjiang; Key Laboratory of Plant Protection Equipment, Ministry of Agriculture and Rural Affairs, Jiangsu University, Zhenjiang, Jiangsu, China.
  • Jian Chen – articles in this journal School of Agricultural Engineering, Jiangsu University, Zhenjiang; Key Laboratory of Plant Protection Equipment, Ministry of Agriculture and Rural Affairs, Jiangsu University, Zhenjiang, Jiangsu, China.
  • Xiaoya Dong – articles in this journal School of Agricultural Engineering, Jiangsu University, Zhenjiang; Key Laboratory of Plant Protection Equipment, Ministry of Agriculture and Rural Affairs, Jiangsu University, Zhenjiang, Jiangsu, China.
  • Baijing Qiu – articles in this journal School of Agricultural Engineering, Jiangsu University, Zhenjiang; Key Laboratory of Plant Protection Equipment, Ministry of Agriculture and Rural Affairs, Jiangsu University, Zhenjiang, Jiangsu, China.
Published
8 September 2025
Section
Original Articles
DOI
10.4081/jae.2025.1736

Abstract

The impact behavior of charged droplets on leaf surfaces with varying degrees of hydrophobicity was experimentally investigated. A high-speed camera was employed to quantitatively capture the impact morphology and motion dynamics of the droplets under different conditions. The study primarily focused on analyzing the effects of three key parameters: static contact angle q, applied voltage U, and droplet Weber number We on the droplet impact dynamics. The results revealed that droplets impacting hydrophobic surfaces exhibited smaller spreading diameters and higher retraction heights compared to those on hydrophilic surfaces. Furthermore, the maximum spreading ratio bmax of charged droplets on the leaf surface was reduced by approximately 10.8%, and the maximum recoiling height ratio H*max decreased by about 28% when compared to the behavior of neutral droplets. Additionally, the impact behavior of droplets on leaves under different We conditions was discussed. With the increase of droplet We from 59 to 175, droplet bmax increased by 34.9% and droplet H*max decreased by 24.1%.

Keywords

Supporting Agencies

National Natural Science Foundation of China (No. 31971790) , Priority Academic Program Development of Jiangsu Higher Education Institutions (No. PAPD2023-87)

References

  1. Appah, S., Jia, W., Ou, M., Wang, P., Asante, E.A. 2020. Analysis of potential impaction and phytotoxicity of surfactant-plant surface interaction in pesticide application. Crop Prot. 127:104961. DOI: https://doi.org/10.1016/j.cropro.2019.104961
  2. Appah, S., Jia, W., Ou, M., Wang, P., Gong, C. 2019. Investigation of optimum applied voltage, liquid flow pressure, and spraying height for pesticide application by induction charging. Appl. Eng. Agr. 35:795-804. DOI: https://doi.org/10.13031/aea.13358
  3. Dai, S., Zhang, J., Jia, W., Ou, M., Zhou, H., Dong, X., H. et al. 2022. "Experimental study on the droplet size and charge-to-Mass ratio of an air-assisted electrostatic nozzle. Agriculture 12:889. DOI: https://doi.org/10.3390/agriculture12060889
  4. Deng, Q., Wang, H., Xie, Z., Zhou, X., Tian, Y., Zhang, Q., X. et al. 2023. Behaviors of the water droplet impacting on subcooled superhydrophobic surfaces in the electrostatic field. Chem. Eng. Sci. 266:118282. DOI: https://doi.org/10.1016/j.ces.2022.118282
  5. Gao, J., Guo, Y., Tunio, M.H., Chen, X., Chen, Z. 2023. Design of a high-voltage electrostatic ultrasonic atomization nozzle and its droplet adhesion effects on aeroponically cultivated plant roots. Int. J. Agr. Biol. Eng. 162:30-37. DOI: https://doi.org/10.25165/j.ijabe.20231602.7222
  6. Gilet, T., Bourouiba, L. 2015. Fluid fragmentation shapes rain-induced foliar disease transmission. J. R. Soc. Interface 12:20141092. DOI: https://doi.org/10.1098/rsif.2014.1092
  7. Gong, C., Jia F., Kang, C. 2024. Deposition of water and emulsion hollow droplets on hydrophilic and hydrophobic surfaces. Agriculture 14:960. DOI: https://doi.org/10.3390/agriculture14060960
  8. Hu, W., Gao, Z., Dong, X., Chen, J., Qiu, B.J.A. 2024. Contact electrification of liquid droplets impacting living plant leaves. Agronomy (Basel) 14:573. DOI: https://doi.org/10.3390/agronomy14030573
  9. Kim, H.Y., Chun, J.H. 2001. The recoiling of liquid droplets upon collision with solid surfaces. Phys. Fluids 13:643-659. DOI: https://doi.org/10.1063/1.1344183
  10. Knight, R.M., Li, X., Hocter, J.S., Zhang, B., Zhao, L., Zhu, H. 2022. Optimization of induction charging of water droplets to develop an electrostatic spray scrubber intended for poultry particulate matter mitigation. T. ASABE 65:815-824. DOI: https://doi.org/10.13031/ja.14913
  11. Law, S.E. 2001. Agricultural electrostatic spray application: a review of significant research and development during the 20th century. J. Electrost. 51:25-42. DOI: https://doi.org/10.1016/S0304-3886(01)00040-7
  12. Li, X., Ratschow, A.D., Hardt, S., Butt, H.-J. 2023. Surface charge deposition by moving drops reduces contact angles. Phys. Rev. Lett. 131:228201. DOI: https://doi.org/10.1103/PhysRevLett.131.228201
  13. Lin, H., Zhou, H., Xu, L., Zhu, H., Huang, H. 2016. Effect of surfactant concentration on the spreading properties of pesticide droplets on Eucalyptus leaves. Biosyst. Eng. 143:42-49. DOI: https://doi.org/10.1016/j.biosystemseng.2016.01.003
  14. Ma, J., Liu, K., Dong, X., Huang, X., Ahmad, F., Qiu, B. 2023. Force and motion behaviour of crop leaves during spraying. Biosyst. Eng. 235: 83-99. DOI: https://doi.org/10.1016/j.biosystemseng.2023.09.012
  15. Mao, T., Kuhn, D.C., Tran, H. 1997. Spread and rebound of liquid droplets upon impact on flat surfaces. AIChE J. 43:2169-2179. DOI: https://doi.org/10.1002/aic.690430903
  16. Roth-Nebelsick, A., Konrad, W., Ebner, M., Miranda, T., Thielen, S., Nebelsick, J.H. 2022. When rain collides with plants-patterns and forces of drop impact and how leaves respond to them. J. Exp. Bot. 73:1155-1175. DOI: https://doi.org/10.1093/jxb/erac004
  17. Ryu, S.U., Lee, S.Y. 2009. Maximum spreading of electrically charged droplets impacting on dielectric substrates. Int. J. Multiph. Flow 35:1-7. DOI: https://doi.org/10.1016/j.ijmultiphaseflow.2008.09.003
  18. Salcedo, R., Llop, J., Campos, J., Costas, M., Gallart, M., Ortega, P., Gil, E. 2020. Evaluation of leaf deposit quality between electrostatic and conventional multi-row sprayers in a trellised vineyard. Crop Prot. 127:104964. DOI: https://doi.org/10.1016/j.cropro.2019.104964
  19. Theodorakis, P.E., Amirfazli, A., Hu, B., Che, Z. 2021. Droplet control based on pinning and substrate wettability. Langmuir 37:4248-4255. DOI: https://doi.org/10.1021/acs.langmuir.1c00215
  20. Wang, T., Zhai, X., Huang, X., Li, Z., Zhang, X., Zou, X., Shi, J. 2023. Effect of different coating methods on coating quality and mango preservation. Food Packaging Shelf 39:101133. DOI: https://doi.org/10.1016/j.fpsl.2023.101133
  21. White, D., Gurung, S., Zhao, D., Tabler, T., McDaniel, C., Styles, D., et al. 2018. Foam or spray application of agricultural chemicals to clean and disinfect layer cages. J. Appl. Poult. Res. 27:416-423. DOI: https://doi.org/10.3382/japr/pfx069
  22. Wu, S., Liu, J., Wang, J., Hao, D., Wang, R. 2021. The motion of strawberry leaves in an air-assisted spray field and its influence on droplet deposition. T. ASABE 64:83-93. DOI: https://doi.org/10.13031/trans.14143
  23. Xu, H., Wang, J., Wang, H., Li, B., Yu, K., Yao, J., et al. 2024. Numerical investigation of droplet impact and heat transfer on hot substrates under an electric field. Int. J. Heat Mass Transf. 229:125721. DOI: https://doi.org/10.1016/j.ijheatmasstransfer.2024.125721
  24. Xu, H., Wang, J., Wang, Z., Yu, K., Xu, H., Wang, D., Zhang, W. 2021. Impact dynamics of a charged droplet onto different substrates. Phys. Fluids 33:102111. DOI: https://doi.org/10.1063/5.0066381
  25. Xu, L., Zhu, H., Ozkan, H.E., Thistle, H.W. 2010. Evaporation rate and development of wetted area of water droplets with and without surfactant at different locations on waxy leaf surfaces. Biosyst. Eng. 106:58-67. DOI: https://doi.org/10.1016/j.biosystemseng.2010.02.004
  26. Yatsuzuka, K., Mizuno, Y., Asano, K. 1994. Electrification phenomena of pure water droplets dripping and sliding on a polymer surface. J. Electrost. 32:157-171. DOI: https://doi.org/10.1016/0304-3886(94)90005-1

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