|Mono-Dispersed Polymer Beads Production
by Microchannel and Its Applications
School of Engineering, The University of Tokyo, Tokyo, Japan
Nippon Gomu Kyokaishi,(2006),79(2),83-87 General Review in Japanese
A new scheme for the polymer beads production using a microfluidic technique is described. This technique is based on the fact that droplets formation at a junction in microchannels is caused by shear stress acting on the dispersed-phase flow by the continuous-phase flow. The Reynolds number in a microchannel was very low which indicated the flow in the microchannel was laminar, therefore, uniform droplet formation was generated. The diameter of the droplets is widely varied from 50% to 300% to the diameter of the dispersed phase flow. Various monomers were used as a dispersed phase, and aqueous solution of polyvinyl alcohol as a continuous phase. Droplets produced in the microchannel were introduced from the drain to the server, and then polymerized by the thermal polymerization method or photo polymerization method. The droplet diameter was monodisperse with CV of less than 5%. Various polymer beads were produced by changing the geometry of the microchannel structure. By using this technique, two colored polymer beads, with different electrical potential for the electronics paper, were produced. We are now approaching to the mass production of the two colored polymer beads which is used for the manufacturing of electronic papers.
Microchannel, Microfluidic device, Microsphere, Mono-disperse, Bi-colored beads, Double emulsion