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Universal spreading of water drops on complex surfaces
B B J Stapelbroek1, H P Jansen, E S Kooij
1Physics of Fluids Group, MESA+ Institute for Nanotechnology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands. j.h.snoeijer@utwente.nl.
Soft Matter
|March 21, 2014
Summary
Water spreading on complex surfaces shows an initial inertial phase (r ~ t(1/2)). The transition to the final state is universally governed by the contact angle, irrespective of surface details.
Area of Science:
- Fluid dynamics
- Surface science
- Materials science
Background:
- The rapid spreading of liquid drops on solid surfaces is a fundamental phenomenon.
- Understanding the influence of surface properties on droplet dynamics is crucial for various applications.
Purpose of the Study:
- To experimentally investigate the early stages of liquid spreading on complex surfaces.
- To analyze the impact of surface micro-texturing, chemical patterning, and softness on spreading dynamics.
Main Methods:
- Experimental deposition of water droplets onto various engineered substrates.
- High-speed imaging to track the wetted area radius over time.
- Analysis of the spreading dynamics across different surface complexities.
Main Results:
- An inertial regime (r ~ t(1/2)) is observed for all tested complex substrates.
- Deviations from pure power-law spreading occur for partially wetting substrates.
- The crossover dynamics to the equilibrium radius exhibit universal behavior, dependent only on the final contact angle.
Conclusions:
- Surface complexity influences spreading dynamics, but an initial inertial regime is robust.
- The final stage of spreading is universally governed by the contact angle, simplifying theoretical models.
- This universal crossover dynamics offers insights into liquid-solid interactions on diverse surfaces.
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