Buckling of elastic filaments by discrete magnetic moments

Boltz, Horst-Holger; Klumpp, Stefan

doi:10.1140/epje/i2017-11576-6

Cited by 5 publications

(3 citation statements)

References 32 publications

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“…Similarly, localized force dipoles and their mutual interactions by distortion of their elastic environment are treated in the theory of defects in crystal structures [103]. In a different context, the question of whether the separated state of the two magnetic particles is stable, and at which point this state collapses and the particles touch each other, has recently been studied in the context of magnetosome filaments [104]. These elastic elements are found, for instance, in magnetotactic bacteria that detect the magnetic field of the earth for their orientation.…”

Section: Discussionmentioning

confidence: 99%

Reversible magnetomechanical collapse: virtual touching and detachment of rigid inclusions in a soft elastic matrix

et al. 2018

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Soft elastic composite materials containing particulate rigid inclusions in a soft elastic matrix are candidates for developing soft actuators or tunable damping devices. The possibility to reversibly drive the rigid inclusions within such a composite together to a close-to-touching state by an external stimulus would offer important benefits. Then, a significant tuning of the mechanical properties could be achieved due to the resulting mechanical hardening. For a long time, it has been argued whether a virtual touching of the embedded magnetic particles with subsequent detachment can actually be observed in real materials, and if so, whether the process is reversible. Here, we present experimental results that demonstrate this phenomenon in reality. Our system consists of two paramagnetic nickel particles embedded at finite initial distance in a soft elastic polymeric gel matrix. Magnetization in an external magnetic field tunes the magnetic attraction between the particles and drives the process. We quantify our experimental results by different theoretical tools, i.e., explicit analytical calculations in the framework of linear elasticity theory, a projection onto simplified dipole-spring models, as well as detailed finite-element simulations. From these different approaches, we conclude that in our case the cycle of virtual touching and detachment shows hysteretic behavior due to the mutual magnetization between the paramagnetic particles. Our results are important for the design and construction of reversibly tunable mechanical damping devices. Moreover, our projection on dipole-spring models allows the formal connection of our description to various related systems, e.g., magnetosome filaments in magnetotactic bacteria.

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Section: Discussionmentioning

confidence: 99%

Reversible magnetomechanical collapse: virtual touching and detachment of rigid inclusions in a soft elastic matrix

et al. 2018

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“…Their dipole moment can either arise from an unscreened magnetic or electric moment, or from screened short-ranged electric interactions, also arising from polar colloidal clusters 106 . It has previously been shown that a chain of magnetic particles can exhibit intrinsic mechanical properties reminiscent of elastic strings or rods [107][108][109][110][111][112] depending on the additional particle interactions. In colloidal suspensions, magnetic interactions often cause flocculation due to the strong attraction at short distances 113 .…”

Section: Introductionmentioning

confidence: 99%

Membrane penetration and trapping of an active particle

Daddi-Moussa-Ider

Goh

Liebchen

et al. 2019

The Journal of Chemical Physics

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The interaction between nano-or micro-sized particles and cell membranes is of crucial importance in many biological and biomedical applications such as drug and gene delivery to cells and tissues. During their cellular uptake, the particles can pass through cell membranes via passive endocytosis or by active penetration to reach a target cellular compartment or organelle. In this manuscript, we develop a simple model to describe the interaction of a self-driven spherical particle (moving through an effective constant active force) with a minimal membrane system, allowing for both penetration and trapping. We numerically calculate the state diagram of this system, the membrane shape, and its dynamics. In this context, we show that the active particle may either get trapped near the membrane or penetrates through it, where the membrane can either be permanently destroyed or recover its initial shape by self-healing. Additionally, we systematically derive a continuum description allowing to accurately predict most of our results analytically. This analytical theory helps identifying the generic aspects of our model, suggesting that most of its ingredients should apply to a broad range of membranes, from simple model systems composed of magnetic microparticles to lipid bilayers. Our results might be useful to predict mechanical properties of synthetic minimal membranes. arXiv:1901.07359v1 [cond-mat.soft]

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“…Magnetic hard spheres are realized in the macroworld as heavy balls [18] and granulates [19], yet a plethora of possibilities are found in the mesoscopic regime of magnetic colloids [20][21][22][23][24][25][26][27][28][29][30][31], magnetic nanoparticles [32][33][34] (in particular, when the magnetic interaction energy dominates thermal fluctuations), colloidal particles with an induced electric dipole moment [35,36] and dipolar dusty plasmas [37]. As these particles and their clusters constitute the main building blocks of prospective materials such as ferromagnetic filaments [38][39][40] for the creation of microdevices and for magnetorheological fluids and ferrogels with tunable and unusual visco-elastic properties [41][42][43][44], an understanding of their structure is of prime interest.…”

Section: Introductionmentioning

confidence: 99%

Ground state of dipolar hard spheres confined in channels

2018

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We investigate the ground state of a classical two-dimensional system of hard-sphere dipoles confined between two hard walls. Using lattice sum minimization techniques we reveal that at fixed wall separations, a first-order transition from a vacuum to a straight one-dimensional chain of dipoles occurs upon increasing the density. Further increase in the density yields the stability of an undulated chain as well as nontrivial buckling structures. We explore the close-packed configurations of dipoles in detail, and we find that, in general, the densest packings of dipoles possess complex magnetizations along the principal axis of the slit. Our predictions serve as a guideline for experiments with granular dipolar and magnetic colloidal suspensions confined in slitlike channel geometry.

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Buckling of elastic filaments by discrete magnetic moments

Cited by 5 publications

References 32 publications

Reversible magnetomechanical collapse: virtual touching and detachment of rigid inclusions in a soft elastic matrix

Reversible magnetomechanical collapse: virtual touching and detachment of rigid inclusions in a soft elastic matrix

Membrane penetration and trapping of an active particle

Ground state of dipolar hard spheres confined in channels

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