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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 42: French-German Session: Nanomaterials, Composites and Hybrids II

CPP 42.4: Vortrag

Mittwoch, 11. März 2026, 18:00–18:15, ZEU/0260

Magneto-active elastomers with magnetically hard vs soft particles: molecular dynamics simulations — •Júlio P. A. Santos and Sofia Kantorovich — University of Vienna, Faculty of Physics, Kolingasse 14-16, 1090 Vienna, Austria

Magneto-active elastomers (MAEs) [1-2], or magnetorheological elastomers (MREs), are composite materials whose properties - such as stiffness, surface roughness (wettability), and shape - can be controlled by low-energy magnetic fields, making them ideal for soft robotics. MAEs consist of an elastic matrix embedded with magnetic micro- or nanoparticles, magnetically either hard (MH) or soft (MS). For high concentrations of MH particles, one can use a complex arrangement of springs that randomly bond nearby MH particles [3]. However, this model oversimplifies particle behavior (as permanent point dipoles) - critical for modeling physically relevant MAEs.

We address these issues in ESPResSo [4], employing molecular dynamics to study the impact of MS particles on the surface relief of a MAE layer and to provide a critical comparison between MH- and MS-based MAEs. At zero field, MS particles do not interact magnetically, whereas MH particles form long chains within the layer. Increasing the field slowly promotes dipolar interactions between the MS particles and rapidly promotes Zeeman interactions with the applied field, leading to chains that preferentially align parallel to it. In contrast, MH chains must break before reorienting in the direction of the magnetic field, due to the greater importance of dipolar interactions relative to Zeeman, requiring larger applied fields for signficant surface structural changes.

Keywords: magneto-active elastomers; magnetic soft matter; soft robotics