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Friedrich Kremer

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Date/Time
Date(s) - 02/27/2018
4:00 pm - 5:00 pm

Location
404 Min H Kao Electrical Engineering and Computer Science Building

Categories


Dr. FriePicture of Friedrich Kremerdrich Kremer

Professor, Molecular Physics

University of Leipzig

 

 

 

 

 

 

 

Bio:

Dr. Friedrich Kremer is professor for molecular physics at the university of Leipzig since 1993. He graduated in theoretical physics (LMU Munich) and received his PhD at the university of Freiburg in experimental biology. From 1978 – 1995 he joined the Max-Planck-Institue (MPI) for solid state physics (Stuttgart) and from1985 – 1993 the MPI for polymer research (Mainz). From 1999 – 2003 he was chairman of the section “Polymerphysics” and “Chemical Physics and Polymerphysics”of the German Physical Society (DPG). His current research interests are Broadband Dielectric Spectroscopy and time-resolved 2D-IR-Spectroscopy. He authored or edited several books and published more than 350 papers in peer-reviewed journals and is advisory editor in chief of  the journal “Colloid and Polymer Science”. In 2005 he received the Karl Heinz Beckurts Award for his achievements in promoting Broadband Dielectric Spectroscopy and its applications. In 2009 he was invited to give the Whitehead Memorial Lecture at the IEEE-CEIDP meeting in Virginia Beach. In 2011 he received  the Wolfgang-Ostwald-Award of the “Deutsche Kolloid Gesellschaft”.

 

Abstract:

F.Kremer, P.Papadopoulos*, R.Figuli (born Ene)**, W.Kossack and M.Anton,

Universität Leipzig

* Max-Planck-Institut für Polymerforschung, Mainz

** Karlsruher Institut für Technologie (KIT), Karlsruhe

Spider silk is a high-performance fiber with unique mechanical properties which are currently not met by man-made materials. It consists essentially out of two proteins, major ampullate spidroin1 and spidroin2, having alanine-rich blocks interrupted by glycine-rich sequences. The former assembles to -sheeted nanocrystals which are embedded in the amorphous chains of the latter and which are interlinked by a ~ 10 % fraction of prestressed chains. This causes within the fiber a negative inner pressure which is counterbalanced by the matrix surrounding the fibrils and by the outer skin. Wetting of the fiber results in a spontaneous “supercontraction” into the equilibrated state. – In the talk a detailed description of this interplay between inner and outer constraints will be discussed based on a variety of complementary experimental methods like polarized, time-resolved FTIR – spectroscopy, measurements of the mechanical modulus and micro-X-ray scattering. It enables one to deduce a quantitative model describing the macroscopic response in the dependence on the microscopic parameters.

References:

1) Papadopoulos, P.; J.Sölter, F. Kremer “Structure-property relationships in major ampullate spider silk as deduced from polarized FTIR spectroscopy”, Eur. Phys. J. E 24, 193-199 (2007)

2) Papadopoulos, P., J. Sölter and F. Kremer “Hierarchies in the structural organization of spider silk – a quantitative model” Colloid and Polymer Science 287, Issue2, 231-236 (2009)

3) Papadopoulos, P., R. Ene, I. Weidner, F. Kremer, “Similarities in the structural organization of major and minor ampullate spider silk” Macromol. Rapid. Commun.30, 851-857 (2009)

4) Ene, R. P. Papadopoulos, F. Kremer “Combined structural model of spider dragline silk”, Soft Matter, 5, 4568-4574 (2009)

5) Ene, R., P. Papadopoulos, F. Kremer “Partial deuteration probing structural changes in supercontracted spider silk“ Polymer 51, 21, 4784-4789 (2010) DOI:10.1016/j.polymer.2010.08.061

6) Spiess, K., R. Ene, C. Keenan, J. Senker, F. Kremer, T. Scheibel “Impact of initial solvent on thermal stability and mechanical properties of recombinant spider silk films“ J.. Mater. Chem., 21, 13594-13604 (2011) DOI: 10.1039/c1jm11700a

7) Ene, R., C. Krywka, S.-G. Kang, P. Papadopoulos, M. Burghammer, E. Di Cola, M. Müller, F. Kremer “Structure changes in Nephila dragline: The influence of pressure” Polymer (2012), DOI: 10.1016/j.polymer.2012.09.045

8) Anton M., W. Kossack, C. Gutsche, R. Figuli (Ene), P. Papadopoulos, J. Ebad-Allah, C. Kuntscher, F. Kremer “Pressure-Dependent FTIR-Spectroscopy on the Counterbalance between External and Internal Constraints in Spider Silk of Nephila pilipes” Macromolecules 46, 4919−4923 (2013) DOI: 10.1021/ma400498v

9) Schneider D., N. Gomopoulos, C.Y. Koh, P. Papadopoulos, F. Kremer, E.L. Thomas, G. Fytas “Nonlinear control of high-frequency phonons in spider silk” Nature Materials (2016) DOI: 10.1038/NMAT4697

 

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