3D printing of passive microfluidic flow mixers using Triply Period Minimal Surface microlattice structures

Microfluidics are miniaturised devices useful for precision fluid handling phases when conducting a range of chemical reactions or biological processes. Such devices operate at micrometre length scales, where laminar flow dominates and so interactions are limited to diffusion between the flowing liquid interfaces unless flow is made turbulent to induce mixing.

Passive mixers are desirable for this task as they comprise geometrical features which can be incorporated during the fabrication of such devices. Designs largely remain planar due to traditional microfluidic manufacturing being conducted with 2.5D fabrication processes.

Additive Manufacturing now allows for passive mixers to now be realised in true 3D but have seen limited investigation. This study explores the efficacy of several miniaturised Triply Period Minimal Surface micro-lattice structures, formed within microfluidic channels as turbulence inducing structures for increased mixing. We explore several lattice designs and report on their efficacy for mixing reactions conducted during continuous flow conditions.