Influence of the meniscus at the bottom of the solid plate on imbibition experiments

The analysis of the experiments on liquid imbibition into porous solids car ried out by using the increase of weight technique proves the influence tha t meniscus formation has on the experimental increase of weight when the bo ttom of the porous layer is put in contact with the free surface of the liq uid used to perform the penetration experiments. This process (meniscus ons et) has a temporary dependence due to the change of the distance between th e inferior base of the plate and the free surface of the liquid as a result of the imbibition, We have also found the proper experimental conditions u nder which such temporary dependence can be minimized after a short time af ter the start of contact between the porous layer and the free surface of t he liquid utilized in the penetration procedure. Thus, the weight increase because of the meniscus formation can be assumed as a constant during the g reatest part of the experiments, allowing the use of the proper mathematica l form of Washburn's equation in order to describe the imbibition of the li quid into the pores of the solid. (C) 2001 Academic Press.