Speaker
Prof.
Friedrich Kremer
(Institute of Experimental Physics I, University of Leipzig, Germany)
Description
The question on what length-scale molecular and especially glassy dynamics of polymers takes place is of fundamental importance and has multifold practical implications as well. Recent results based on Broadband Dielectric Spectroscopy [1,2] for nanometric thin (≥5 nm) layers of poly(styrene) [3], poly(methylmethacrylate) [4,5] and poly(cis-1,4-isoprene) [6] will be presented, delivering the concurring result that deviations from glassy dynamics of the bulk never exceed margins of ±3 K independent of the layer thickness, the molecular weight of the polymer under study and the underlying substrate. A further exciting perspective is the measurement of the dynamics of condensed isolated polymer chains [7]. The experiments lead to the conclusions that glassy dynamics takes place on the length scale a few polymer segments (≤ ~ 0.5 nm) while the conformation of the chain as a whole is strongly modified due to geometrical confinement.
References
1. F.Kremer, A. Schoenhals (Eds.) Broadband Dielectric Spectroscopy, Springer, Berlin 2003
2. Kremer F., E. U. Mapesa, M. Tress, M. Reiche, “Molecular Dynamics of Polymers at Nanometric Length Scales: From Thin Layers to Isolated Coils” in:“Recent Advances in Broadband Dielectric Spectroscopy”, Y. P. Kalmykov (Eds.), NATO Science for Peace and Security Series B: Physics and Biophysics, Chapter 12, Springer (2012), DOI 10.1007/978-94-007-5012-8, ISBN: 978-9-400-75011-1
3. Tress, M, M. Erber, E.U. Mapesa, H. Huth, J. Müller, A. Serghei, C. Schick, K.-J. Eichhorn, B. Voit and F. Kremer, “Glassy Dynamics and Glass Transition in Nanometric Thin Layers of Polystyrene“, Macromolecules 43, 9937-9944 (2010) DOI: 10.1021/ma102031k
4. Erber, M., M. Tress, E.U. Mapesa, A. Serghei, K.-J. Eichhorn, B. Voit and F. Kremer “Glassy dynamics and glass transition in thin polymer layers of PMMA deposited on different substrates“, Macromolecules 43, 7729 (2010), DOI: 10.1021/ma100912r
5. Mapesa, E.U., M. Erber, M. Tress, K.-J. Eichhorn, A. Serghei, B. Voit and F. Kremer “Glassy dynamics in nanometer thin layers of polystyrene“, Europ. Phys. J. - Special Topics 189, 173-180 (2010), DOI: 10.1140/epjst/e2010-01320-2
6. Mapesa, E.U., M. Tress, G. Schulz, H. Huth, C. Schick, M. Reiche, F. Kremer “Segmental and chain dynamics in nanometric layers of poly (cis-1,4-isoprene) as studied by Broadband Dielectric Spectroscopy and temperature-modulated Calorimetry”, Soft Matter, (2013) DOI: 10.1039/C3SM51311D
7. Tress, M., E.U. Mapesa, W. Kossack, W.K. Kipnusu, M. Reiche, F. Kremer, “Glassy Dynamics in Condensed Isolated Polymer Chains”, Science, (2013), MS no: RE1238950/JEC/MAT SCI.
Primary author
Prof.
Friedrich Kremer
(Institute of Experimental Physics I, University of Leipzig, Germany)
