Patent Document ID: 20020166766
Application ID: 09813571
Patent Flag: 0

Claim One:
1. A method of fractionation of a mixture of particles comprising: providing a first electrode positioned in the first plane and a second electrode positioned in a second plane different from the first plane, an electrolyte solution located therebetween and a plurality of particles suspended at an interface between the electrolyte solution and the second electrode, wherein the second electrode comprises a planar electrode having a surface and an interior, the surface or the interior having been patterned to modify the spatial distribution of the interfacial electric field, and wherein the particles comprise at least two types of particles, each particle type having a distinguishable relaxation frequency; and generating an electric field between the first and the second electrode by applying an AC voltage between the two electrodes, said electric field having a frequency that is less than or equal to the relaxation frequency of at least one of said particle types but greater than the relaxation frequencies of other particle types, wherein the electric field in combination with the patterning of the electrode produces fractionation of the particles having relaxation frequencies greater than or equal to the frequency of the electric field from other particles.