Flagellar dynamics of chains of active Janus particles fueled by an AC electric field
This is a modal window.
The media could not be loaded, either because the server or network failed or because the format is not supported.
Formal Metadata
Title |
| |
Title of Series | ||
Number of Parts | 31 | |
Author | 0000-0002-6390-5072 (ORCID) 0000-0002-2560-5650 (ORCID) | |
License | CC Attribution 3.0 Unported: You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor. | |
Identifiers | 10.5446/38863 (DOI) | |
Publisher | ||
Release Date | ||
Language |
Content Metadata
Subject Area | ||
Genre | ||
Abstract |
|
00:00
AerodynamicsParticleKette <Zugmittel>Electric power distributionParticle physicsPlain bearingElectricityVideoComputer animation
00:03
AerodynamicsParticleKette <Zugmittel>MechanicElectric currentParticle physicsChainSemiconductor device fabricationElectrodeMetalDielectricCamera lensParticleElectrodeNeutronenaktivierungKette <Zugmittel>Self-propelled anti-aircraft weaponAerodynamicsFlexibility (anatomy)Initiator <Steuerungstechnik>
00:38
Kette <Zugmittel>ParticleSemiconductor device fabricationMetalDielectricElectrodeCamera lensElectricityWednesdayParticleDirect currentComputer animation
00:47
MetalElectricityKette <Zugmittel>ParticleSemiconductor device fabricationElectrodeDielectricElectric power distributionElectric chargeParticlePlane (tool)Electric power distributionIonAmplitudeConcentratorCrystal structureAudio frequencyBarricadeElectric chargeSchwellenspannungChainMetalCharge densityAerodynamicsComputer animation
01:28
Audio frequencyKette <Zugmittel>IceRF engineeringPhase (matter)RRS DiscoveryChainCompact CassetteChainAudio frequencyMapRotary engineCylinder headConstraint (mathematics)Bending (metalworking)TrajectoryNyquist stability criterionFormation flyingHot workingParticleDirect currentModel buildingWegfahrsperreLangwelleKette <Zugmittel>ElectrodeComputer animation
02:48
Phase (matter)Chandrasekhar limitTrajectoryKette <Zugmittel>Mode of transportAerodynamicsMarine propulsionAudio frequencyVoltageDisc brakePitch (music)Scale (map)ForceParticleAudio frequencyVoltageNegativer Widerstand
03:27
AerodynamicsMarine propulsionAudio frequencyDisc brakeForceVoltageQuadrupoleIncandescent light bulbKette <Zugmittel>Electric power distributionMagnetic coreMeasurementVertical integrationParticleAerodynamicsRefractive indexKette <Zugmittel>PaperCharge densityVolumetric flow rateComputer animation
03:51
Incandescent light bulbMarine propulsionKette <Zugmittel>FeatherWatchComputer animation
Transcript: English(auto-generated)
00:04
We experimentally study the active dynamics of flexible chains of self-propelled colloidal particles. How can we understand the fascinating dynamics of biological flagella, as seen in Sperma's analogy? To answer this question, we created artificial flagella composed of self-propelled active colloidal particles
00:22
and compared their beating behaviors. First, we fabricated generous particles which are colloidal particles with distinct hemispheres. We suspended generous particles in NACL solutions and sandwiched them between two transparent two-dimensional electrodes. Due to gravity, the particles were segmented very close to the bottom electrodes.
00:43
Then we applied an AC electric field in the vertical direction, and the particles start to swim in the horizontal plane, interacting with each other. By tuning the frequency and the amplitude of the applied electric field and the ion concentration of the solution, the particles exhibit dynamical chain structures.
01:02
How do the particles interact and form such chains? Under the AC electric field with frequency higher than a certain threshold frequency, induced electric charges on the surface of the particles have opposite signs on the two hemispheres due to the difference in the response time of the dielectric and metal hemispheres.
01:24
This quadrupolar charge distribution results in attractive interaction between the particles, and this attractive interaction is responsible for the chain formation. Interestingly, we can also control the direction of motion of the generous particles by changing the frequency of the electric field.
01:44
In the low frequency regime, the particles move towards their dielectric sides. On the other hand, in the high frequency regime, they move towards their metal sides. In previous works, chain formation was only observed in the high frequency regime, but in this work, we have discovered that the chain formation at the low frequency regime
02:05
is possible by thoroughly exploring the parameter space. Depending on the constraints imposed on their heads, the chains exhibit oscillatory or rotary motions. In particular, when the formless particles of the chain are both positionally and orientationally fixed,
02:22
the chains exhibit stable fragile-like beating behavior. We studied this in detail. Such beating behavior can be observed when the formless particles are tethered on the bottom electrode or when they hit obstacles or aggregates of immobile particles. The beating chains exhibit characteristic trajectories in the real space.
02:43
However, as a matter of fact, the principal component analysis has shown that they can be interpreted as quite simple oscillations between the first and the second principal components. In our system, the self-proportional speed or the self-proportional force can be controlled by the applied voltage.
03:01
Taking this advantage, we studied how the beating frequency scales with the self-proportional force of the composing particles. Our experiment shows that the beating frequency was proportional to the self-proportional force. However, this scaling relation deviates from theoretical predictions made previously.
03:22
We have resolved this discrepancy by taking into account the quadrupole-quadrupole interactions of the generous particles. However, our measurement gives the indirect but first reliable experimental evidence on the quadrupolar charge distribution of the particles. Finally, we theoretically calculated the flow field around the beating generous chains
03:44
to examine the role of hydrodynamics in the beating behavior. For more details, please look at the paper. Thank you for watching.