Dr. Jörg Hachenberg (2003 - 2006)

++49 - 551 - 39 7612 e-mail Georg-August-Universität Göttingen I. Physikalisches Institut Friedrich-Hund-Platz 1 37077 Göttingen Germany

• Macroscopic temperature dependent properties of glasses, liquids such as elasticity, viscosity, glass transition, damping
• Microscopic processes in glasses like atomic movement, diffusion, hopping, glass deforming, internal friction
• Universality of glass properties, comparison between soft matter and metallic glasses

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Mechanical spectroscopy is used to investigate the dynamics in copolymers and other systems (see cooperations) by looking at the relaxation modes. This can be done in temperature space at frequencies ranging from quasi static to 50 Hz (Perkin Elmer DMA7, see figure) by expanding, compressing or bending the sample or at 5.4 kHz and in the MHz regime by supplementary techniques. The focus is always on the question how microscopic characteristics of a well defined sample influence the macroscopic mechanical properties and what can be learned from the observed dynamics.

PCGG activities

Cooperation(s):

• Steisel - Buback group (Synthesis of copolymers)
• Scharf - Krebs group (Polymers in reduced dimensions: Pulsed Laser Deposited thin films)
• Cho - Griesinger group (Fibrils: α-synuclein)
• Vana group (RAFT polymers)
• Diezemann - Diederichsen group (Synthetic oligopeptides)

• Solid phase synthesis and analysis of biooligomers (April 2004)
  

• Project Week in the Diederichsen Group: Solid phase peptide synthesis (SPPS) and analysis of Biooligomers

• ♦ J. Hachenberg, D. Bedorf, K. Samwer, R. Richert, A. Kahl, M. D. Demetriou, W. L. Johnson, Merging of the alpha and beta relaxations and aging via the Johari-Goldstein modes in rapidly quenched metallic glasses, Appl. Phys. Lett. 2008, 92, 131911.
• ♦ J. Hachenberg, B. Steisel, U. Nergui, D. Bedorf, M. Buback, K. Samwer, Effect of Chemical Confinement on the mechanical relaxation spectra of poly(ethene-co-methacrylic acid) copolymers, Int. J. Mater. Res. 2008, 99, 502-506.
• ♦ J. Hachenberg, K. Samwer, Indications for a slow β-relaxation in a fragile metallic glass, J. Non-Crys. Solids 2006, 352, 5110-5113.
• ♦ P. Rösner, J. Hachenberg, K. Samwer, R. Wehn, P. Lunkenheimer, A. Loidl, E. Süske, T. Scharf, H. U. Krebs, Comparision of mechanical and dielectric relaxation processes in laser-deposited poly(methyl methacrylate) films, New J. Phys. 2006, 8, 89.
• ♦ J. Hachenberg, C. Streng, E.Süske, S. Vauth, S. G. Mayr, H.-U. Krebs, K. Samwer, Kinetic roughening of laser deposited polymer films: Crossover from single particle character to continuous growth, Phys. Rev. Lett. 2004, 92, 246102.

• Talk: Jun 08 2007 Beta relaxation and aging: one effect on two timescales (Glastag)
• Poster: April 10 2006 Indications for a slow ß-relaxation in strong and fragile metallic glasses (2nd International Workshop on Dynamics in Viscous Liquids)
• Participation: Mar 26 2006 (Frühjahrstagung der DPG 2006)
• Poster: Mar 21 2006 Mechanical spectroscopy of copolymers: Chemical confinements in poly(ethylene-co-methacrylic acid) (Review Colloquium)
• Talk: Mar 21 2006 Mechanical spectroscopy of copolymers: Chemical confinement? (Review Colloquium)
• Talk: Mar 10 2006 Mechanical spectroscopy of copolymers (Seventh Workshop 2006
  Spectroscopy and Dynamics of Molecular Coils and Aggregates (Göttingen - Paris))
• Organization: Mar 10 2006 Session Chair (Seventh Workshop 2006
  Spectroscopy and Dynamics of Molecular Coils and Aggregates (Göttingen - Paris))
• Poster: Mar 08 2006 Poly[ethene-co-methacrylic acid]: Physical analysis (Seventh Workshop 2006
  Spectroscopy and Dynamics of Molecular Coils and Aggregates (Göttingen - Paris))
• Poster: Feb 07 2006 Mechanical spectroscopy of metallic glasses and copolymers (Edgar-Lüscher-Seminar)
• Talk: Sept 05 2005 Relaxations in the proximity of the glass transition (Sixth Workshop 2005)
• Talk: Jul 10 2005 (5th International Discussion Meeting on Relaxation in Complex Systems)
• Organization: Jun 15 2005 Host student of Hubert Mantz
• Poster: May 10 2005 (PhD Course in Protein Fibrilation and Aggregation)
• Poster: April 06 2005 Mechanical Spectroscopy on Metals as Model Systems (Fifth Workshop = 91st Bunsen Colloquium 2005)
• Poster: Mar 10 2005 (Frühjahrstagung der DPG 2005)
• Talk: Feb 10 2005 (Edgar-Lüscher-Seminar)
• Organization: Feb 09 2005 Host student of Anatoli Serghei
• Poster: Sept 20 2004 Spectroscopy of polymers at low frequencies (Fourth Workshop 2004)
• Talk: Mar 19 2004 Mechanical spectroscopy of polymers (Third Workshop 2004)
• Poster: Mar 10 2004 (Frühjahrstagung der DPG 2004)
• Poster: Feb 10 2004 (Edgar-Lüscher-Seminar)
• Talk: Jun 18 2003 Surface growth of laser deposited organic thin films (Seminar SS 2003)
• Talk: Mar 10 2003 (Frühjahrstagung der DPG 2003)
• Poster: Feb 10 2003 (Edgar-Lüscher-Seminar)