Fig. S6.

Optical images of the mixers. (A) The passive mixer consists of a Y-type junction and a long duct of hydraulic diameter $\mathit{d}=500$ µm and length $\ell =15$ mm. The channel surfaces of the passive mixers are shown in the magnified image. (B) The active mixer consists of two inlet channels connecting to the central mixing volume of length $\ell =30$ mm, diameter $\mathit{d}=3$ mm, and outlet diameter ${\mathit{a}}_{\mathit{n}}=500$ µm with the impeller of diameter $\mathrm{\Delta }=\mathrm{2}.\mathrm{7}$ mm. The two types of impellers are shown in the magnified image. An alternative design with metal fixtures is implemented for mixing with highly viscous epoxy systems.