Development of novel method to create three-dimensional arrangements of particles using dielectrophoresis in artificially nonuniform electric field

We have developed a novel method to arrange particles three-dimensionally using dielectrophoresis in suspension under an artificially nonuniform electric field. Particles can be attracted to electric field intensity maxima and are aligned parallel to an electric field. This alignment is called a "particle chain." As a result, the particle chains are formed only on micro pillars of metal preformed at selected positions on a flat electrode, because the electric field shows a maximum intensity on tips of the pillars. Two-dimensional arrangements of the one-dimensional chains lead to three-dimensional arrangements of the particles. Since uncured polymer is utilized as a suspension medium, the arrangements are stabilized by curing the polymer on healing. Using this method, we succeed in creating three-dimensional arrangements of glass beads with a diameter of 30 mu m in silicone elastomer. In addition, we confirm particle-chain formation of silica spheres with a 5 mu m diameter, which suggests possibility of three-dimensional arrangements of micron-order silica particles and submicron-order particles with a large permittivity such as BaTiO3.