Impact dynamics of non-Newtonian droplet on superhydrophobic surfaces

Mehdi H. Biroun, Luke Haworth, Hossein Abdolnezhad, Arash Khosravi, Prashant Agrawal, Glen McHale, Hamdi Torun, Ciro Semprebon, Masoud Jabbari, Yongqing Fu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Droplet impact behaviour on a solid surface is critical for many industrial applications such as spray coating, food production, printing, and agriculture. For all these applications, a common challenge is to modify and control the impact regime and contact time of the droplets. This challenge becomes more critical for non-Newtonian liquids with complex rheology. In this research, we explored the impact dynamics of non-Newtonian liquids (by adding different concentrations of Xanthan into water) on superhydrophobic surfaces. Our experimental results show that by increasing the Xanthan concentration in water, the shapes of the bouncing droplet are dramatically altered, e.g., its shape at the separation moment is changed from a conventional vertical jetting into a “mushroom”-like one. As a result, the contact time of the non-Newtonian droplet could be reduced by up to50%. We compare the impact scenarios of Xanthan liquids with those of glycerol solutions having a similar apparent viscosity, and results show that the differences in the elongation viscosity induce different impact dynamics of the droplets. Finally, we show that by increasing the Weber number for all the liquids, the contact time is reduced and the maximum spreading radius is increased.
Original languageEnglish
JournalLangmuir
Publication statusAccepted/In press - 3 Mar 2023

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