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Wettability-defined droplet imbibition in ceramic mesopores
Adnan Khalil1, Felix Schäfer, Niels Postulka
1Ernst-Berl-Institut für Technische und Makromolekulare Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany. annette.andrieu-brunsen@tu-darmstadt.de.
Nanoscale
|December 8, 2020
Summary
Controlling surface wettability of mesoporous silica films precisely tunes water imbibition dynamics. Changes in hydrophilicity affect liquid movement and evaporation, revealing insights into nanoscale fluid behavior in porous materials.
Area of Science:
- Materials Science
- Surface Chemistry
- Nanotechnology
Background:
- Wettability-driven liquid infiltration in porous media is crucial for natural processes and industrial applications.
- Understanding nanoscale wettability and liquid movement in mesopores is essential for advanced material design.
Purpose of the Study:
- To systematically investigate water imbibition in mesoporous silica thin films with chemically tuned wettability.
- To observe and analyze the interplay between nanoscale wettability, liquid movement, and evaporation dynamics.
Main Methods:
- Chemical functionalization of mesoporous silica thin films to precisely adjust surface wettability.
- Top-view imaging using collimated coaxial illumination to observe water droplet imbibition.
- Analysis of imbibition kinetics, area changes, and oscillations using a modified Lucas-Washburn law.
Main Results:
- Decreasing hydrophilicity reduced the maximum imbibition area and altered imbibition kinetics and mechanisms.
- Water-mediated surface activation at the imbibition front led to increased wettability over time.
- Spontaneous condensation-evaporation imbalances caused imbibition front oscillations, with amplitude decreasing at higher contact angles.
Conclusions:
- Wettability is a critical factor governing water movement in mesoporous silica.
- Observed phenomena like surface activation and oscillation damping offer insights for designing nano/microfluidic devices and water management systems.
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