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Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure
Published on: April 17, 2018
Roughness-enhanced collection of condensed droplets
Joachim Trosseille1, Anne Mongruel2, Laurent Royon3
1Physique et Mécanique des Milieux Hétérogènes, CNRS, ESPCI Paris - PSL University, Sorbonne Université, Sorbonne Paris Cité, 75005, Paris, France. joachim.trosseille@espci.fr.
The European Physical Journal. E, Soft Matter
|November 28, 2019
Summary
Surface roughness from sand-blasting surprisingly enhances droplet shedding for passive dew harvesting. This method increases nucleation sites and drop coalescence, improving water collection efficiency by about 30%.
Area of Science:
- Materials Science
- Surface Engineering
- Water Harvesting
Background:
- Droplet pinning limits gravity shedding, hindering low condensation processes like passive dew harvesting.
- Passive dew harvesting offers a sustainable alternative water source, but efficiency is often limited by droplet removal.
Purpose of the Study:
- To investigate the effect of surface roughness on droplet shedding during condensation.
- To enhance the efficiency of passive dew harvesting systems.
Main Methods:
- Experimental analysis of droplet behavior on sand-blasted surfaces with varying roughness.
- Observation of nucleation, coalescence, and shedding dynamics under controlled condensation conditions.
- Evaluation of water collection rates on modified substrates, including edge effects.
Main Results:
- Moderate sand-blasting, increasing surface roughness, paradoxically improved droplet shedding compared to smoother substrates.
- Enhanced nucleation site density and sub-micron scale droplet coalescence accelerated drop sliding.
- Substrate edges facilitated water collection through early sliding of larger drops, acting as natural wipers.
- Combined effects of sand-blasting and edge design increased dew condensation collection rates by approximately 30%.
Conclusions:
- Controlled surface roughening via sand-blasting is an effective strategy to overcome droplet pinning in condensation.
- Optimized surface treatments can significantly enhance the performance of passive dew harvesting technologies.
- The synergistic effect of surface modification and substrate geometry offers a promising approach for efficient water collection.
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