Development of a new micromixer based on split/recombination for mass production and its application to soap free emulsifier

We fabricated two new types of multi-stage micromixers, YM-1 and YM-2. In these devices, mixing is achieved through the repeated splitting and recombination of the fluid flow. It was shown that the two types of micromixers presented here were capable to produce soap free emulsions at short contact times. From the investigation of the effects of the device wall material, the number of stages, etc. on the size of the droplets in the resulting emulsion, it was clarified that the emulsion was formed through efficient mixing achieved by utilizing the interactions which uniquely occur in microspaces, particularly between the device wall and fluid flow. The attained maximum production rates of emulsion in experiments were 5 1/h for YM-1 and 20 1/h for YM-2, respectively. To show the applicability of the mixers to other purposes, rapid extraction of phenol from dodecane by water was also conducted. It was found that YM-1 has a potential to continuously extract phenol even at extremely high flow rates (mixing times within I s). These results show that, although the mixers are extremely small, they have the capability to be used in fairly large-scale industrial plants. (C) 2004 Elsevier B.V. All rights reserved.