A tunable magnetic axis microdevice using polymer-dispersed liquid crystal doped with magnetic nanoparticles

Abstract

This work proposes a magnetic microdevice with a tunable magnetic axis. The proposed device was realized by patterning a polymer-dispersed liquid crystal (PDLC) material doped with magnetic nanoparticles. An in situ technique of re-polarizing the magnetic axis of the device using small magnetic fields was also presented. The PDLC-based microdevice was fabricated using the standard polymerization-induced phase separation method and a simple lithography process. The re-polarization was achieved by applying a moderate magnetic field of less than 30 mT. The locomotion of the device, including translational motion, rotational motion, and magnetic re-polarization, was demonstrated in a polydimethylsiloxane microfluidic channel by using two pairs of Helmholtz coils. The measured results also showed that the time required for magnetic re-polarization decreases with the intensity of the magnetic field applied. The velocities of the devices driven in the microfluidic channel with different magnetic field gradients were also measured.