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Wettability-defined droplet imbibition in ceramic mesopores

Khalil, Adnan ; Schäfer, Felix ; Postulka, Niels ; Stanzel, Mathias ; Biesalski, Markus ; Andrieu-Brunsen, Annette (2022):
Wettability-defined droplet imbibition in ceramic mesopores. (Postprint)
In: Nanoscale, 12 (47), Royal Society of Chemistry, ISSN 2040-3372,
DOI: 10.26083/tuprints-00021744,
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Item Type: Article
Origin: Secondary publication service
Status: Postprint
Title: Wettability-defined droplet imbibition in ceramic mesopores
Language: English
Abstract:

Wettability-defined liquid infiltration into porous materials in nature and several industrial applications is of fundamental interest. Direct observation of wetting-controlled imbibition in mesopores is anticipated to deliver important insights into the interplay between nanoconfined liquid movement and nanoscale wettability. We present a systematic study of water imbibition into mesoporous silica thin films with wetting properties precisely adjusted through chemical functionalization. We observe the liquid infiltration, resulting in an imbibition ring around the water droplet, by top-view imaging using a camera with collimated coaxial illumination. With decreasing hydrophilicity, the maximum imbibition area around the droplet decreases, accompanied by a simultaneous change in the imbibition kinetics and imbibition mechanism. Initially, the imbibition kinetics follow a modified Lucas–Washburn law that considers a strong influence of evaporation. However, with increasing imbibition time after reaching constant imbibition ring dimensions, the imbibition area starts to increase again, causing a deviation from the applied model. This observation is ascribed to water-mediated surface activation at the imbibition front, leading to a slightly increased wettability, which is also confirmed by water adsorption measurements. Furthermore, recently described spontaneous condensation-evaporation imbalances that cause oscillations of the imbibition front could be verified and were studied with regard to changing wetting properties. By increasing the contact angle of the material and therefore the partial pressure needed for capillary condensation, the amplitude of the imbibition front oscillations decreases. These results provide insights into the wettability-defined complex movement of water in mesoporous structures, which has practical implications, e.g., for nano/microfluidic devices and water purification or harvesting.

Journal or Publication Title: Nanoscale
Volume of the journal: 12
Issue Number: 47
Place of Publication: Darmstadt
Publisher: Royal Society of Chemistry
Collation: 8 Seiten
Classification DDC: 500 Naturwissenschaften und Mathematik > 540 Chemie
Divisions: DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 1194: Interaction between Transport and Wetting Processes > Research Area A: Generic Experiments > A05: Wetting and Transport on Swellable, Immobilized Polymer Brushes and Polymer Networks
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 1194: Interaction between Transport and Wetting Processes > Research Area C: New and Improved Applications > C04: Controlled Dynamic Wetting and the Influence of Ionic Mass Transport in Mesoporous Film
Profile Areas > Thermo-Fluids & Interfaces
07 Department of Chemistry > Fachgebiet Makromolekulare Chemie
TU-Projects: DFG|SFB1194|TP A05 Biesalski
DFG|SFB1194|TP C04 Andrieu-Bruns
Date Deposited: 22 Jul 2022 12:45
Last Modified: 22 Jul 2022 12:46
DOI: 10.26083/tuprints-00021744
Corresponding Links:
URN: urn:nbn:de:tuda-tuprints-217445
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/21744
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