4D synchrotron microtomography and pore-network modelling for direct capillary flow visualization in 3D printed microfluidic channels

• Published in: Lab on a chip 2020-06, Vol.2 (13), p.243-2411
• Main Authors: Piovesan, Agnese, Van De Looverbosch, Tim, Verboven, Pieter, Achille, Clement, Parra Cabrera, Cesar, Boller, Elodie, Cheng, Yin, Ameloot, Rob, Nicolai, Bart
• Format: Article
• Language: English
• ISSN: 1473-0197; 1473-0189
• DOI: 10.1039/d0lc00227e

Powder-based 3D printing was employed to produce porous, capillarity-based devices suitable for passive microfluidics. Capillary imbibition in such devices was visualized in situ through dynamic synchrotron X-ray microtomography performed at the European Synchrotron Radiation Facility (ESRF) with sub-second time resolution. The obtained reconstructed images were segmented to observe imbibition dynamics, as well as to compute the system effective contact angle and to generate a pore-network to model capillary imbibition. A contact angle gradient was observed resulting in a preferential wicking direction, with the central portion of the microfluidic channel filling faster than the edge areas. The contact angle analysis and the pore-network model results suggest that this is due to spatial variations in the material surface properties arising from both the 3D printing and the subsequent drying processes. We investigate fluid flow at the pore scale in novel 3D printed microfluidic channels through synchrotron microtomography and pore-network modelling.