Shaping of microparticles in electric-field cages

US5948328A · kind A · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Stefan Fiedler · Berlin, DE
• Andreas Voigt · Regensburg, DE
• Thomas Schnelle · Berlin, DE
• Guenter R. Fuhr · Berlin, DE
• Torsten Mueller · Zirndorf, DE
• Rolf Hagedorn · Berlin, DE
• Jan Hornung · Berlin, DE
• Henning Glasser · Berlin, DE
• Bernd Wagner · Looft, DE

Key dates

• Filing date: Aug 23, 1996
• Grant date: Sep 7, 1999
• Expiry date: Aug 23, 2016

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J19/087
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

In the method proposed, microparticles suspended in a liquid or droplets suspended in a liquid with which they are immiscible are shaped by high-frequency electric fields in a three-dimensional electrode array of a size in the micrometer or submicrometer range and subsequently consolidated by prior art chemical bonding procedures or by physical methods. The disposition, geometry and control of the electrodes determine the shape of the particles. The particles themselves must have a conductivity and/or relative dielectric constant lower than the solution surrounding them. For some, this can be achieved only at certain frequencies in the kHz and MHz band which are determined by the passive electrical properties of the particles and the surrounding solution. The particles or droplets are repelled by the electrodes so that they are shaped in the free solution without making contact with any surface and can then be consolidated. This makes it possible to shape micrometer and submicrometer size particles of the kind required in chromatography, affinity biochemistry and medicine, as well as for filter systems.