Berlin 2018 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 51: Hydrogels and Microgels

CPP 51.6: Talk

Wednesday, March 14, 2018, 16:15–16:30, C 264

Modelling of shock wave dynamics in ferrogels — •Segun Goh, Andreas M. Menzel, and Hartmut Löwen — Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany

Ferrogels are smart soft materials, consisting of a gel network and embedded magnetic particles. Novel phenomena, such as the response of elasticity to external magnetic fields, emerge consequently. Due to the difficulties in describing the touching/separating processes of magnetic particles, however, the dynamics of ferrogels remain largely unveiled. In this study, we consider a one dimensional chain consisting of magnetic dipoles and springs between them as a simple model for ferrogels. To probe the dynamics theoretically, we investigate a continuum limit of the double-well type potential governing the system and the corresponding equation of motion. It is then revealed that a type of spinodal decomposition underlies the touching/separating dynamics of the magnetic particles. We further elucidate the formation of touching/separating particle clusters as well as the migration of interfaces in terms of shock solutions. Comparisons of the continuum theory with the particle-resolved simulation are also given. We expect that these results will provide insight into understanding the dynamics of more realistic models with randomness in parameters and time-dependent magnetic fields.