Dual Pathways of Air Cavity Evolution during Droplet Impact on Superhydrophobic Nanoporous Surfaces

Mi Zhou; Yujun Lin; Zhanli Geng; Feiyang Zhang; Limin Zhou; Yue Shen; Lijuan Zhang; Wei Ding; Elmar Bonaccurso; Longquan Chen; Thomas Wallmersperger; Binyu Zhao; Günter K. Auernhammer

doi:10.1103/1wt7-hf7l

Dual Pathways of Air Cavity Evolution during Droplet Impact on Superhydrophobic Nanoporous Surfaces

Mi Zhou ^1,2,*, Yujun Lin^2,*, Zhanli Geng ^1,*, Feiyang Zhang ^1,3,*, Limin Zhou ⁴, Yue Shen ¹, Lijuan Zhang⁴, Wei Ding ⁵, Elmar Bonaccurso ⁶ et al.

Longquan Chen⁷, Thomas Wallmersperger ⁸, Binyu Zhao ^1,2,3,†, and Günter K. Auernhammer ²

¹Key Laboratory of Green and High-end Utilization of Salt Lake Resources, Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
²Leibniz Institute of Polymer Research, 01069 Dresden, Germany
³University of Chinese Academy of Sciences, Beijing 100049, China
⁴Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
⁵Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
⁶Airbus Central R & T, Materials 1XRM, 81663 Munich, Germany
⁷School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
⁸Institute of Solid Mechanics, Technische Universität Dresden, 01069 Dresden, Germany

^*These authors contributed equally to this work.
^†Contact author: binyuzhao@isl.ac.cn

PDF

Phys. Rev. Lett. 136, 114001 – Published 16 March, 2026

DOI: https://doi.org/10.1103/1wt7-hf7l

Abstract

The impact of a liquid droplet on a solid surface generates a cylindrical air cavity along the droplet’s central axis and entraps a thin air film underneath, with a liquid film potentially sandwiched in between. We observe that the air cavity produced by impacting a water droplet on superhydrophobic nanoporous surfaces evolves via two distinct pathways within a narrow Weber number range ( $W e \approx 2 - 5$ ): bulk-bubble entrapment or air-cushion development. Ultrafast synchrotron x-ray imaging reveals three air-cavity pinch-off mechanisms: (i) inertia-dominated axial implosion due to rapid droplet recoiling, (ii) capillary-wave-driven necking triggered by liquid film rupture, and (iii) hybrid pinch-off. We demonstrate that the stability of the sandwiched liquid film critically determines the pathway selection. Whereas intact liquid films enable isolation of the air cavity and air film, leading to bulk-bubble entrapment, submillisecond liquid film rupture ( $≲ 0.5 ms$ ) redirects the air-cavity pinch-off dynamics, developing an air cushion underneath the droplet.

Physical Review Letters

Export citation

Export citation

Dual Pathways of Air Cavity Evolution during Droplet Impact on Superhydrophobic Nanoporous Surfaces

Abstract

Physics Subject Headings (PhySH)

Authorization Required

Other Options

Supplemental Material (Subscription Required)

References (Subscription Required)

Outline

Information

Filter

Filter

Article Lookup

Enter a citation

Dual Pathways of Air Cavity Evolution during Droplet Impact on Superhydrophobic Nanoporous Surfaces

Abstract

Physics Subject Headings (PhySH)

Authorization Required

Log in via your institution

Log in via APS Member Subscription

Other Options

Supplemental Material (Subscription Required)

References (Subscription Required)