Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 2: Focus: Field Controllable Functional Polymers I

CPP 2.9: Vortrag

Montag, 16. März 2015, 12:15–12:30, C 264

Mesoscopic modeling of ferrogels and magnetic elastomers — Peet Cremer¹, Giorgio Pessot¹, Mitsusuke Tarama^1,2, Elshad Allahyarov¹, Hartmut Löwen¹, and •Andreas M. Menzel¹ — ¹Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany — ²Kyoto University, Kyoto, Japan

Ferrogels and magnetic elastomers consist of colloidal magnetic particles embedded in a crosslinked polymer matrix. Tunable elastic moduli that can be switched by an external magnetic field represent one of their outstanding features. Our goal is to understand and identify such controllable material properties on the magnetic particle level using both particle-matrix and simplified dipole-spring models.

We studied how the particle arrangement and orientation of the magnetic moments can influence the elastic moduli when the strength of the magnetic interaction is controlled. In one case, we used the particle distribution of a real experimental sample as an input. Here, the convenient technical assumption of affine deformations must be dropped. Furthermore, we demonstrated that the relaxation dynamics of the materials can be tuned by the particle arrangement, by external magnetic fields, and by an orientational memory. Apart from that we showed that a pronounced switchable nonlinear stress-strain behavior is found under suitable circumstances.

In the future, we aim at a connection of our characterization to more microscopic and to macroscopic scales. We have already taken the first steps into these directions by comparing to minimum Monte-Carlo simulations and by performing a simplified coarse-graining procedure.