Debye-Stokes-Einstein Fractional Law in a Polymeric Liquid Crystal: A Non-Linear ESR Study by Using Spin Probes with Different Symmetries

Abstract

The reorientation of spin probes with very different aspect ratios, dissolved in a polymeric liquid crystal, is studied by non-linear Electron Spin Resonance. A scaling law between the rotational correlation time τ and the macroscopic viscosity, as measured via the dynamic shift factor a_T , is found. A discussion on the current interpretations of the scaling, which takes the form τ a ^ξ _T with 0 ≤ ξ ≤, is given.