Fabrication and fluidic characterization of static micromixers made of low temperature cofired ceramic (LTCC)

Abstract

Microreaction devices used for chemical synthesis must possess a high resistance against corrosive chemicals. Therefore, microreaction devices were made of glass, steel or ceramics. Photolithographic steps combined with etching processes as well as micropowder blasting or micromilling processes were applied for the formation of appropriate structures. The low temperature cofired ceramics (LTCC) technology combines easy structuring, assembling and packaging techniques with the high chemical resistance of a glass ceramic material. In contrast to the known ceramic technologies, the LTCC technology enables a fast and easy fabrication of microfluidic devices. Here, we present two micromixers made of LTCC and its fluidic characterization. Laser ablation was used for the structuring of green tapes which were layered and cofired to form the micromixers. X-type fluidic barriers were realized inside a 1mm2 squared meandered channel of about 160mm length. A meandered channel mixer without X-type mixing structures was used as a reference. The pressure drop was measured for aqueous media with various viscosities and the friction factors were calculated. An exponential equation for the friction factor prediction is given. The residence time distribution was determined for both devices by pulse trace experiments and the dispersion model was used to describe the residence time distribution for low Reynolds numbers.