DL plays a fundamental role in many real-world systems. For instance, milk exists only because fat droplets are covered with a double layer that prevent their coagulation into butter. DLs exist in practically all heterogeneous fluid-based systems, such as blood, paints, inks, ceramic slurries and cement slurries.
* In general, adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate (the molecules or atoms being accumulated) on the surface of the adsorbent.More on double-layers at http://en.wikipedia.org/wiki/Double_layer_(interfacial)
An electric double-layer capacitor, also known as supercapacitor, supercondenser, pseudocapacitor, electrochemical double layer capacitor(EDLC), or ultracapacitor, is an electrochemical capacitor with relatively highenergy density, typically on the order of thousands of times greater than anelectrolytic capacitor.