Direct measurement of Lighthill's energetic efficiency of a minimal magnetic microswimmer

Calero, Carles; García-Torres, José; Ortiz-Ambriz, Antonio; Sagués, Francesc; Pagonabarraga, Ignacio; Tierno, Pietro

doi:10.1039/c9nr05825g

Cited by 14 publications

(8 citation statements)

References 41 publications

(39 reference statements)

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“…In this work we raise the question to how the confinement effects are modified for active matter. In order to answer that question, we use a simple butterfly-like flat molecular motor [44][45][46][47][48][49][50][51][52][53][54] (Figure 1), to activate with its periodic folding the supercooled liquid surrounding it, confined in nano-pores of various radii (Figures 2 and 3). Experimentally our motor can be seen as a simplification of the azobenzene molecule or derivatives, which undergoes a photo-isomerization process [27,[55][56][57][58][59][60][61][62][63][64][65] when subject to a light stimulus.…”

Section: Introductionmentioning

confidence: 99%

Activation of a supercooled liquid confined in a nanopore

Mercier,

Delhaye,

Teboul

2021

Preprint

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It is well stablished that confinement of supercooled liquids in nano-pores induces various effects as a strong modification of the dynamics and a layering of the local structure. In this work we raise the issue as how these confinement effects are modified when the liquid is out of equilibrium. To answer that question, we use molecular dynamics simulations to investigate the effect of confinement on a supercooled liquid activated by the periodic folding of a molecular motor. We find that the motor's opening angle controls the activation of the medium and use that result to study the effect of different activations on the confined supercooled liquid. We observe an increase of the activation effect on the dynamics when the medium is confined. We find that the confinement slowing down dependence with the pore radius depends on the activation of the liquid. We argue that these findings result from a modification of dynamic correlation lengths with activation. In this picture the activation permits to control the liquid correlation length and dynamics inside the pore. Studying the local structure we observe a modification of the layering organization induced by the activation. We also find that the mobility inside the pore depends on the layers, being larger where the local density is small.

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Section: Introductionmentioning

confidence: 99%

Activation of a supercooled liquid confined in a nanopore

Mercier,

Delhaye,

Teboul

2021

Preprint

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“…for targeted in vivo healthcare as well as important frameworks from which to advance the understanding of locomotion strategies at the microscopic scale. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The swimming strategies employed by eukaryotic and prokaryotic cells that generate thrust by the sinusoidal-like beating and the corkscrew rotation of flagellum, respectively, have been of particular inspiration to man-made designs. [4,7,13,[21][22][23] To mimic the former, and facilitate a non-time-symmetric swimming stroke, artificial microswimmers require jointed and/or inherently flexible frameworks that are typically actuated using external stimuli, for example, magnetic/electric fields, monochromatic light, or acoustic waves.…”

Section: Doi: 101002/adma202006237mentioning

confidence: 99%

Programmable Design and Performance of Modular Magnetic Microswimmers

et al. 2021

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Synthetic biomimetic microswimmers are promising agents for in vivo healthcare and important frameworks to advance the understanding of locomotion strategies and collective motion at the microscopic scale. Nevertheless, constructing these devices with design flexibility and in large numbers remains a challenge. Here, a step toward meeting this challenge is taken by assembling such swimmers via the programmed shape and arrangement of superparamagnetic micromodules. The method's capacity for design flexibility is demonstrated through the assembly of a variety of swimmer architectures. On their actuation, strokes characterized by a balance of viscous and magnetic forces are found in all cases, but swimmers formed from a series of size‐graded triangular modules swim quicker than more traditional designs comprising a circular “head” and a slender tail. Linking performance to design, rules are extracted informing the construction of a second‐generation swimmer with a short tail and an elongated head optimized for speed. Its fast locomotion is attributed to a stroke that better breaks beating symmetry and an ability to beat fully with flex at high frequencies. Finally, production at scale is demonstrated through the assembly and swimming of a flock of the triangle‐based architectures to reveal four types of swimmer couplings.

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“…Further we explore the average propulsion speed of the pair by fixing the static field to B x = 2.15mT and by varying both the amplitude of the oscillating field B y and the driving frequency ν. In particular, we vary ν ∈ [5,30]Hz and B y ∈ [1.36, 3.16]mT and observe a maximum speed of V = 7µm/s for the extreme values of both parameters 37 . Above 30Hz, the nanorod becomes asynchronous with the swinging field and it cannot follow its fast oscillations, thus 30Hz represent a critical (or step-out) frequency.…”

Section: Propulsion Mechanismmentioning

confidence: 99%

“…In our previous work 37 , we have realized experimentally a hybrid magnetic microswimmer composed by a ferromagnetic nanorod and a paramagnetic microsphere. The couple assembled and propelled when it was actuated by a swinging magnetic field which performed periodic oscillations around a fixed axis and induced consecutive rotation and translation of the nanorod close to the surface of paramagnetic particle.…”

Section: Introductionmentioning

confidence: 99%