Three-step decay of time correlations at polymer-solid interfaces
Institute of Physics, Johannes-Gutenberg-University - 55099 Mainz, Germany, EU
2 Institute of Physics, Martin-Luther-University - 06099 Halle, Germany, EU
Accepted: 26 March 2012
Two-step decay of relaxation functions, i.e., time scale separation between microscopic dynamics and structural relaxation, is the defining signature of the structural glass transition. We show that for glass-forming polymer melts at an attractive surface slow desorption kinetics introduces an additional time scale separation among the relaxational degrees of freedom leading to a three-step decay. The inherent length scale of this process is the radius of gyration in contrast to the segmental scale governing the glass transition. We show how the three-step decay can be observed in incoherent scattering experiments and discuss its relevance for the glass transition of confined polymers by analogy to surface critical phenomena.
PACS: 82.35.Gh – Polymers on surfaces; adhesion / 64.70.Q- – Theory and modeling of the glass transition / 81.05.Qk – Reinforced polymers and polymer-based composites
© EPLA, 2012