Attachment/detachment hysteresis of fiber-based magnetic grabbers

Abstract

We developed an experimental protocol to analyze the behaviour of a model fiber-based magnetic grabber. A fiber is vertically suspended and fixed to the substrate by its upper end. A magnetic droplet is attached to the free end of the fiber and when a permanent magnet approaches the droplet, the fiber is forced to bow and finally jumps to the magnet. It appears that one can flex the micro-fibers by very small micro or even nano-Newton forces. Using this setup, we discovered a hysteresis of fiber attachment/detachment: the pathway of the fiber jumping to and off the magnet depends on the distance between the magnet and the clamped end. This phenomenon was successfully explained by the Euler-Benoulli model of an elastic beam. The observed hysteresis of fiber attachment/detachment was attributed to the multiple equilibrium configurations of the fiber tip placed in a dipole-type magnetic field.

Flexible Magnetic Filaments and their Applications

“…Besides manipulation by magnetic torques as described above, the fl exible rods also may be manipulated by application of forces from permanent magnets. [ 27 ] The behavior of fl exible magnetic rods under the simultaneous action of shear fl ow and magnetic fi eld so far has not been studied extensively. Here we can mention only, [ 28 ] where during numerical simulation of the fi lament in a shear fl ow with the velocity gradient parallel to the fi eld, a periodic interplay of buckling corresponding to S-like mode and straightening of the fi lament was observed.…”

Magnetic Rotational Spectroscopy for Probing Rheology of Nanoliter Droplets and Thin Films

“…The permanent magnets are mostly used when one needs to generate high gradients of the magnetic field [65,104,[109][110][111][112][113][114][115][116]. When the stage with a magnet rotates or moves back and forth, the nanoparticles readily follow the generated field.…”