Electroosmosis, originating in the Debye-layer near the solid/liquid boundary within a fully-saturated porous substrate, can pump successfully against the capillary pressure arising from the surface tension of a droplet placed in series with the pump. As droplet size diminishes, the voltage required to pump electroosmotically down-scales favorably. The technological implication is that electromechanical transducers made of large arrays of small droplets, so-called 'droplet micro-manipulators', and Debye-layer 'diagnostic machines', inferring zeta-potential by measuring interface deflection of a droplet-pump-droplet configuration, become feasible. These applications will be illustrated and we will describe the current modeling of such multi-scale interfacial systems, highlighting open questions that might benefit from an applied mathematical approach.