02766nas a2200265   4500008004100000022001400041245005700055210005700112260000800169490000700177520201300184653001302197653002002210653002202230653001902252653001302271653000902284653002002293653001702313653000902330100002802339700001802367700002702385856008802412       2017                        eng d  a1744-683X00aCapillary uptake in macroporous compressible sponges0 aCapillary uptake in macroporous compressible sponges  cSEP0 v133 a<p><span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; background-color: rgb(248, 248, 248);">The capillarity-driven uptake of liquid in swellable, highly porous sponges is of significant industrial importance. Sponges prepared using polymers and their composites with carbon nanotubes and graphene have been reported, with extraordinary solvent uptake capacities and with the ability to separate oil from water. However, the effect of systematic variation of sponge characteristics on solvent uptake has not been investigated. Here, we report experiments that study capillary uptake in a variety of flexible, centimetre-sized macroporous cylindrical sponges. We used ice-templating to prepare a series of model macroporous sponges in which the porosity, modulus and composition were systematically varied. We investigated two kinds of sponge: (a) those composed purely of cross-linked polymers and (b) those prepared as composites of inorganic particles and polymers. Both kinds of sponge are flexible and exhibit elastic recovery after large compressive deformation. All sponges were characterized thoroughly with respect to their pore microstructure and elastic modulus. When one end of a sponge is plunged into a large reservoir, water rises through capillary action against gravity. We observed a transition from an inertial capillary regime, where the liquid column height rose linearly with time, t, to a viscous capillary regime, where the liquid height rose with time t(0.5). We showed that these results can be rationalized using analyses developed for rigid sponges. We combined differential momentum balance equations for uptake in rigid capillaries with the phenomenological Ergun-Forchheimer relations to account for the effect of the sponge microstructure. This approach works remarkably well in the viscous capillary regime and shows that capillary uptake is governed primarily by the total porosity and pore dimensions of soft sponges.</span></p>10aaerogels10aBuilding blocks10aCatalyst Supports10aContact-angels10aDynamics10aflow10aOrganic Liquids10aPorous-Media10aRise1 aChatterjee, Soumyajyoti1 aDoshi, Pankaj1 aKumaraswamy, Guruswamy  uhttp://library.ncl.res.in/content/capillary-uptake-macroporous-compressible-sponges