Abstract
To investigate the use of magnetic microbeads for swimming at low Reynolds number, the flexible structure of microchains comprising superparamagnetic microbeads under the influence of oscillating magnetic fields is examined experimentally and theoretically. For a ductile chain, each particle has its own phase angle trajectory and phase-lag angle to the overall field. This present study thoroughly discusses the synchronicity of the local phase angle trajectory between each dyad of beads and the external field. The prominently asynchronous trajectories between the central and outer beads significantly dominate the flexible structure of the oscillating chain. In addition, the dimensionless local Mason number (Mnl) is derived as the solo controlling parameter to evaluate the structure of each dyad of beads in a flexible chain. The evolution of the local Mason number within an oscillating period implies the most unstable position locates near the center of the chain around 0.6P<t<0.8P. Moreover, a chain with a certain length in the influence of the oscillating field would behave the most significant deformation and have the most flexible structure.
Highlights
We further study the flexible mechanism of a chain both theoretically and experimentally in the presence of an oscillating field
The effect of the local Mason number on the behaviors of a flexible chain is demonstrated by using Eq (3) to determine the value of local Mn for each dyad of chains subjected to various experimental conditions
It is seen that the P14 chain appears the most significant S-shape among those flexible chains, which qualitatively demonstrate the P14 chain has the most flexible structure and corresponds to the distribution of equilibrium value of Mnmax presented in figure 5
Summary
Magnetic microbeads chains have recently drawn high attention due to their promising potential microfluidic systems[1,2,3,4,5] and biomedical applications.[6,7,8,9,10,11] Magnetic actuation enables motion of the magnetic micro devises to be controlled wirelessly without affecting biological viability but with the extra benefit that the direction of motion can be determined by the field.[12,13] One of the challenges in proposing the micro devices to move in the low-Reynolds-number regime should be that a microswimmer must deform without structural instability in a way that is not invariant under time-reversal. A novel dimensionless parameter RT, including both effects of the Mason number and length of the chain, is derived by Gao et al.[22] to characterize rotational bead chain dynamics. Motivated by these works, we further study the flexible mechanism of a chain both theoretically and experimentally in the presence of an oscillating field. We thoroughly discuss the synchronicity of the local phase angle trajectory between each dyad of beads and the external field for a ductile chain. The local Mason number (denoted as Mnl) is derived as the solo controlling parameter to more accurately evaluate the structural stability of a flexible chain in an oscillating field
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
