Dynamics of liquid imbibition through paper with intra-fibre pores

We present a combined experimental and theoretical investigation of the dynamics of liquid imbibition through paper. The Washburn equation is widely used to describe the dynamics of capillary flow through paper, but this classical model has limited accuracy, which often makes it difficult to use in...

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Bibliographic Details
Published inJournal of fluid mechanics Vol. 845; pp. 36 - 50
Main Authors Chang, Sooyoung, Seo, Jaedeok, Hong, Seokbin, Lee, Duck-Gyu, Kim, Wonjung
Format Journal Article
LanguageEnglish
Published Cambridge, UK Cambridge University Press 25.06.2018
Subjects
Accuracy
Capillary flow
Cellulose
Cellulose fibers
Contact angle
Dynamics
Fibers
Flow control
Imbibition
JFM Papers
Mathematical models
Model accuracy
Physics
Point of care testing
Pores
Porosity
Porous materials
Porous media
capillary flows
microfluidics
porous media
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Summary:We present a combined experimental and theoretical investigation of the dynamics of liquid imbibition through paper. The Washburn equation is widely used to describe the dynamics of capillary flow through paper, but this classical model has limited accuracy, which often makes it difficult to use in developing analytic systems such as paper-based microfluidic devices. We here report that the internal cavity of the cellulose fibres composing paper is significantly responsible for the limited accuracy of the Washburn equation. Our experiments demonstrated that liquid can be absorbed in the internal cavity of the cellulose fibres as well as in the inter-fibre pores formed by the fibre network. We developed a mathematical model for liquid imbibition by considering the flow through the intra-fibre pores based on experimental measurements of the intra-structure of cellulose fibres. The model markedly improves the prediction of the liquid absorption length, compared with the results of the Washburn equation, thus revealing the physics behind the limits of the Washburn equation. This study suggests that the accurate description of capillary imbibition through paper require parameters characterizing the internal pores of the cellulose fibres comprising the paper. Our results not only provide a new insight into porous media flows with different sized pores, but also provide a theoretical background for flow control in paper-based microfluidic systems.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2018.235