Heterogeneous relaxation dynamics of nano-confined salol probed by DMAW. Schranz1, M. R. Puica1, J. Koppensteiner1, H. Kabelka1 and A. V. Kityk2
1 Nonlinear Physics Group, Faculty of Physics of the University of Vienna - Boltzmanngasse 5, A-1090 Wien, Austria
2 Institute for Computer Science, Technical University of Czestochowa - Armii Krajowej 17, PL 42-200 Czestochowa, Poland
received 7 December 2006; accepted in final form 19 June 2007; published August 2007
published online 18 July 2007
We present novel low-frequency (0.1 Hz50 Hz) measurements of the complex elastic susceptibility of the glass-forming liquid salol confined to nanoporous Vycor glass. Our data can be perfectly interpreted with the assumption of a radial distribution of Vogel-Fulcher temperatures T0(r) inside the pores, resulting from an increase of the molecular relaxation time with decreasing distance from the rough pore surface as recently found by computer simulations (Scheidler et al., Europhys. Lett. 59, 701 (2002)). The results show for the first time, that the dynamic elastic response is extremely sensitive for separating confinement-induced acceleration effects of the molecular dynamics and surface-induced slowing-down due to rough pore interfaces.
64.70.Pf - Glass transitions.
61.20.Lc - Time dependent properties; relaxation.
62.25.+g - Mechanical properties of nanoscale materials.
© Europhysics Letters Association 2007