ESR 06: Wetting-dewetting flow in vibrating sessile drop and nanoparticle self-assembly

To investigate the dynamics of drop vibration on a solid substrate, especially the wetting-dewetting behaviour, and to characterize
the self-assembly of solid particles on interfaces and contact lines.
Expected Results:
– An experimental setup for investigation of vibrating drop of nanosuspensions;
– experimental data for the drop shape and wetting dynamics at substrates of different wettabilities;
– experimental data for particle self-assembly at liquid-solid interface and at
contact line.

  • Study of Vibrating Drops

    A custom experimental setup has been developed by ESR 6 to investigate the dynamic behavior of liquid droplets on laterally vibrated substrate. This setup employs high-speed imaging techniques to capture and analyze the dynamic behavior of droplets. Additionally, Laser-Induced Fluorescence is used to visualize the internal flow patterns within the droplets. Below, is reported a sketch illustrating the core components of this setup.

  • Exploring the Dynamic Behavior of a Water Droplet on a Vibrating Superhydrophobic Surface

    The results of the dynamic behavior of a 10-microliter water droplet on a vibrating superhydrophobic surface at 40 Hz are presented in the video below. Key parameters essential for the study of droplet dynamics are obtained using a custom image processing code designed for this specific application. The video reveals the temporal evolution of critical parameters: maximum droplet width, maximum height, and lateral displacement of the center of mass. Playback of the video has been reduced to 5% of its original speed.

    Additionally, a video that provides insight into the internal flow dynamics of an identical droplet undergoing the same conditions is also reported. This video showcases the transition from undisturbed flow, initially induced by evaporation, to a rotating internal flow resulting from the droplet’s rolling behavior caused by the applied vibration.