Abstract for the talk at 03.12.2007 (12:00 h)Oberseminar MATERIALS
Harald Pleiner (Max Planck Institute for Polymer Research)
Nematic liquid crystal and magnetic elastomers and gels
We discuss recent progress in the understanding of the static and dynamic properties of nematic liquid single crystal elastomers as revealed by new experiments. Various descriptions invoking softness, semi-softness, or non-softness, as well as broken symmetries are discussed and compared. The relation between linear and nonlinear elastic properties is considered. Special emphasis is laid on the role of relative rotations between the nematic orientation and the polymer network. The second part of the talk deals with magnetic gels, a novel class of materials that combines the physical and material properties of a magnetic liquid or a magneto-rheological fluid with those of a polymer network. We give a general introduction to the macroscopic description of ferrogels focusing on the novel physical aspects unknown from other materials.