High-speed NMR imaging of capillary action in thin nontransparent porous media

An improved high-speed NMR profiling method is introduced that enables us to measure capillary action in thin, nontransparent porous media. Liquid profiles can be measured as fast as 10 ms with a spatial resolution of 14.5μm. Capillary absorption of microliter-sized droplets into nontransparent nylon-6,6 porous membranes was studied. In nylon-6,6 sharp fronts obeying a one-dimensional Darcy model were observed. In paper the uptake did not follow this model: retardation in uptake, broader fluid fronts, and swelling was observed. These measurements nicely demonstrate the possibilities and versatility of the developed method.