# Multiscale phenomena in molecular matter

Jul 3 – 6, 2017
Europe/Warsaw timezone

## Scaling of the dielectric response of supercooled disordered phases

Jul 4, 2017, 1:00 PM
20m
oral presentation Soft matter and glass formers

### Speaker

Dr Miroslaw Galazka (Institute of Nuclear Physics Polish Academy of Sciences)

### Description

Spectrum of a dielectric permittivity for supercooled disordered phases most often is composed of two relaxation processes [1]: a main relaxation process (called $\alpha$ process) followed by resolved, unresolved (also called ‘excess wing phenomena’), or both secondary processes ($\beta$ processes). Although there are many models describing dielectric relaxation [2-6] none of them describes the relaxation processes in supercooled disordered phases with a good precision, because of some simplifications introduced. Debye model [2] describes relaxation for non-interacting electric dipoles or electric dipoles in diluted non-polar medium whereas Debye-like models, i.e. Cole-Cole [3], Cole-Davidson [4], Havriliak-Negami [5], describe relaxation for non-interacting electric dipoles in viscous medium. Therefore, some scaling equations of the dielectric response were proposed [7-9] to describe molecular dynamics as a function of frequency of measuring field for various temperatures. However, they are limited to scaling of the imaginary part of dielectric permittivity only [7-9], and Nagel and co-authors model [7-8] refers in fact to systems with ‘special’ values of long-range and short-range correlation parameters of molecular interactions. Therefore, we have proposed a general form of scaling equation [10-11] that can be applied to the imaginary part of permittivity $\epsilon$”($f$) as well as to the real part of permittivity $\epsilon$’($f$)-$\epsilon_\infty$. The proposed scaling of the dielectric response applied to supercooled disordered phases, i.e. supercooled isotropic liquid phase and supercooled plastic-crystal phase, shows that behavior of resolved and/or unresolved $\beta$ relaxations strictly depends on the parameters of the main relaxation process. One can conclude that the main relaxation process and the secondary ones are not independent processes. References [1] A. Kudlik et al., $\textit{J. Non-Cryst. Solids}$ $\textbf{235-237}$ (1998) 406. [2] F. Kremer, A. Söchnhals, $\textit{Broadband Dielectric Spectroscopy}$, Springer-Verlag Berlin Heidelberg (2003). [3] K. S. Cole, R. H. Cole, $\textbf{J. Chem. Phys.}$ $\textbf{9}$ (1941) 341. [4] D. W. Davidson, R. H. Cole, $\textit{J. Chem. Phys.}$ $\textbf{18}$ (1951) 1417. [5] S. Havriliak, C. A. Negami, $\textit{J. Polym. Sci. Part C}$ $\textbf{14}$ (1966) 99. [6] L. A. Dissado, R. M. Hill, $\textit{Proc. R. Soc. A}$ $\textbf{390}$ (1983) 131. [7] N. Menon, S. R. Nagel, $\textit{Phys. Rev. Lett.}$ $\textbf{71}$ (1993) 4095. [8] P. K. Dixon, L. Wu, S. R. Nagel, B. D. Williams, J. P. Carini, $\textit{Phys. Rev. Lett.}$ $\textbf{65}$ (1990) 1108. [9] Z. Dendzik, M. Paluch, Z. Gburski, J. Zioło, $\textit{J. Phys.: Condens. Matt.}$ $\textbf{9}$ (1997) L339. [10] M. Gałązka, E. Juszyńska-Gałązka, N. Osiecka, M. Massalska-Arodź, A. Bąk, $\textit{J. Appl. Phys.}$ $\textbf{118}$ (2015) 064101. [11] M. Gałązka, E. Juszyńska-Gałązka, N. Osiecka, A. Bąk, $\textit{Phase Transitions}$ $\textbf{89}$ (2016) 341. Acknowledgments Partial support by the 2014-2016 PAS-CNR bilateral project “Studies of phase polymorphism and dynamics in selected soft materials” and by the 2017-2019 PAS-CNR bilateral project “Multidisciplinary studies of structural and dynamic properties of glass-forming compounds” is acknowledged.

### Primary author

Dr Miroslaw Galazka (Institute of Nuclear Physics Polish Academy of Sciences)

### Presentation materials

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