Grants and Contributions:

Grant or Award spanning more than one fiscal year (2017-2018 to 2018-2019).

Absorption of liquid into paper towel is a complex process: it involves a surface tension driven flow in ax000D
porous and elastic network that swells and deforms when in contact with liquid. Analysis of surface tensionx000D
driven flow in a capillary dates back a century to the work of Lucas and Washburn on capillary rise. Whilex000D
early work on capillary driven flow focused primarily on the regime where capillary forces balance viscousx000D
forces, if the walls of the pore (or of the porous media) are flexible then elastic forces arise due to thex000D
deformation of the pore. The dynamics of elasto-capillary rise have only recently been explored, and it has beenx000D
shown that for sufficiently flexible channels the fluid penetration is retarded compared to rigid channels. Inx000D
paper towel, plies are not only elastic, but also porous and so we propose here to extend recent work onx000D
elasto-capillary flow to include porous walls. We aim to determine the relative importance of surface tension,x000D
elasticity and porosity over length and time scales which are relevant to paper towel and tissue absorption in anx000D
effort to improve the performance of these products.