Fabrication of anisotropic microparticles by laser ablation and laser heating

Laser ablation and laser heating were used as micro-cutting and micro-bonding tools for fabrication of anisotropic microparticles. By using the techniques, two kinds of anisotropic microparticles to which a polymer film or magnetic particles was attached on their one hemisphere were fabricated from transparent spherical acrylic polymer particles of about 10 μm. In the fabrication of the anisotropic particles to which a polymer film attached, a mono-particle layer of the acrylic polymer particles formed on water surface was transferred on to a target plate coated with a polymer film and the plate was heated so that the particles strongly adhered to the polymer film. The plate was irradiated by 1064 nm or 532 nm pulse light from a Q-switched YAG laser to cause the ablation of the target. The ablation blew off the polymer film together with the acrylic polymer particles from the target plate, which gave the anisotropic particles. Anisotropic particles to which magnetic particles attached on their one hemisphere were fabricated by laser heating. A magnetic particle layer formed on water surface was transferred onto a quartz plate and then the monoparticle layer of the acrylic polymer particles was transferred onto the magnetic particle layer. The magnetic particles were heated by irradiation of 808 nm light from a CW diode laser, which caused the adhesion of the magnetic particles to the polymer particles. Rotation of the obtained magnetically anisotropic particles under rotating magnetic field was demonstrated. - Highlights: • Laser ablation and laser heating were used for fabrication of anisotropic particles. • Anisotropic microparticles having a polymer film or magnetic particles on their one hemisphere were fabricated. • The magnetically anisotropic microparticles rotated under a rotating magnetic field