Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 5: Polymer Networks and Dynamics I: Elastomers and Magnetic Materials

CPP 5.6: Talk

Monday, March 20, 2017, 12:00–12:15, ZEU 255

Switchable nonlinear stress-strain properties and dynamic behavior of magnetic gels — Peet Cremer, Giorgio Pessot, Hartmut Löwen, and •Andreas M. Menzel — Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany

Magnetic gels, ferrogels, and magnetorheological elastomers consist of magnetic colloidal particles embedded in a permanently crosslinked, possibly swollen, elastic polymer matrix. Many of their material properties can be reversibly switched from outside using magnetic fields.

Two of such switchable features are presented and analyzed. First, these are nonlinear stress-strain properties of materials containing chain-like particle aggregates [1,2]. We had previously identified intermediate plateau-like regimes on the stress-strain curves that are tunable by external magnetic fields [1]. Now, we report on the effect of different magneto-mechanical couplings between the magnetic moments and the elastic matrix that qualitatively influence the overall behavior [2]. Second, we determine linear dynamic properties, starting from mesoscopic particle-based models [3]. We analyze the influence of different particle arrangements and magnetic interactions on the linear dynamic storage and loss moduli. Depending on the frequency of the stimulus, qualitatively different trends are observed.

Both aspects are important for the application of magnetorheological gels and elastomers, e.g., as soft actuators or tunable dampers.

[1] Cremer et al., Appl. Phys. Lett. 107, 171903 (2015).

[2] Cremer et al., Phys. Chem. Chem. Phys. 18, 26670 (2016).

[3] Pessot et al., J. Chem. Phys. 145, 104904 (2016).