Axel Mellinger


Assistant Professor
Physics

Dow Science Complex 222
989-774-3336
alex.mellinger@cmich.edu

Education

Physics Diploma, Technische Universität München, 1992
Ph.D., Physics, Max-Planck Institut für extraterrestrische Physik, Garching, Germany, 1995
Habilitation, Department of Physics, University of Potsdam, 2005

Research Fields

  • Ferroelectret polymers: new concepts for piezoelectric sensors and actuators
  • Non-destructive 3D space-charge and polarization tomography
  • Polymer-dispersed liquid crystals with ferroelectric host polymers
  • Microscopic mechanisms of charge storage in electret polymers
  • Photo- and thermally stimulated discharge currents in charge-storing fluorinated and cycloolefin polymers

Current Research Projects

  • Dielectric barrier discharges in ferroelectret polymers. Ferroelectrets (i.e., charged cellular polymers) are rendered piezoelectric by means of barrier discharges inside the air-filled voids. Unlike traditional piezoceramics, they are mechanically flexible and can be manufactured to cover large areas. However, much remains to be learned about the microscopic processes of charging and charge-trapping. Achieving this goal requires a multi-technique approach, combining spectroscopic plasma diagnostics with space-charge mapping and electromechanical characterization techniques.
  • Non-destructive 3D space-charge and polarization tomography. The ability to accurately and non-destructively measure polarization and space-charge distributions is of prime importance in the research on electrets and organic electronics. Applications include the accumulation of space charge in high-voltage cable insulations, the development and optimization of pyroelectric and piezoelectric sensors, and basic research into the mechanisms of charge storage in electret polymers.

Selected Publications

  • X. Qiu, R. Gerhard and A. Mellinger, "Turning Polymer Foams or Polymer-Film Systems into Ferroelectrets: Dielectric Barrier Discharges in the Voids", IEEE Trans. Diel. Electr. Insul. 18(1), 34-42 (2011).
  • A. Mellinger and O. Mellinger, "Breakdown Threshold of Dielectric Barrier Discharges in Ferroelectrets: Where Paschen's Law Fails", IEEE Trans. Diel. Electr. Insul. 18(1), 43-48 (2011).
  • R. Flores Suárez, L. M.Ganesan, W. Wirges, R. Gerhard and A. Mellinger, "Imaging Liquid Crystals Dispersed in a Ferroelectric Polymer Matrix by Means of Thermal-pulse Tomography", IEEE Trans. Diel. Electr. Insul. 17(4), 1123-1127 (2010).
  • L. M. Ganesan, W. Wirges , A. Mellinger and R. Gerhard, "Piezo-optical and electro-optical behaviour of nematic liquid crystals dispersed in a ferroelectric copolymer matrix", J. Phys. D: Appl. Phys. 43, 015401 (2010).
  • X. Qiu, R. Gerhard and A. Mellinger, "In-situ Acoustical Investigation of the Polarization Build-up in Cellular Polypropylene Ferroelectrets", IEEE Trans. Diel. Electr. Insul. 17(4), 1043-1049 (2010).
  • C.-D. Pham, A. Petre, L. Berquez, R. Flores Suárez, A. Mellinger, W. Wirges and R. Gerhard, "3D high-resolution mapping of polarization profiles in thin poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) films using thermal techniques", IEEE Trans. Diel. Electr. Insul., 16(3), 676-681 (2009).
  • A. Mellinger, "A Color All-Sky Panorama Image of the Milky Way", Publications of the Astronomical Society of the Pacific 121, 1180-1187 (2009).