Eur. Phys. J. E 5, 511-517 (2001)
Effect of the network on the director fluctuations in a nematic side-group elastomer analysed by static and dynamic light scattering
M. Schönstein, W. Stille and G. StroblFakultät für Physik, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany stille@uni-freiburg.de
(Received 10 April 2001)
Abstract
Static and dynamic light scattering experiments
were performed on monodomains of a crosslinked nematic side-group polysiloxane.
The depolarized scattering caused by fluctuations of the nematic director was
analysed. Due to a superposed strong static scattering produced by heterogeneities
the fluctuating part of the scattering intensity was found to be rather small.
In contrast to low molar mass nematics, the relaxation rates and strength did
not show a significant dependence on the scattering vector. The results can
be explained by restoring torques on the director originating from the coupling
to the network elasticity which dominate those originating from the Frank elasticity.
Quantities describing the coupling as well as effective viscosities for the
director reorientation were obtained.
61.30.-v - Liquid crystals.
61.41.+e - Polymers, elastomers, and plastics.
78.35.+c - Brillouin and Rayleigh scattering; other light scattering.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001
