This paper reports modelling, fabrication and testing of two micromixe
rs, The principle of mixing used for the devices was diffusion because
of the small value of the Reynolds number in microcapillaries. The fi
rst mixer separates the main flow into partial flows, which are latera
lly alternated in order to increase the boundary surface between the l
iquids. The second mixer superposes two fluids by injection of one liq
uid into the other. The fabrication technology is based on etching of
silicon and anodically bonding with Pyrex glass. The performance of th
e mixers has been verified by mixing phenolphthalein solution and ammo
nia dissolved in water. Reasonable mixing was achieved at pressures of
around 4 kPa (lateral mixing) and 7 kPa (vertical mixing) with flow r
ates of approximately 1 mu l min(-1). The measurements were compared w
ith diffusive mixing simulations with a CFD simulator and agreement of
both was observed.