A Novel Passive Polymeric Micromixer Using 3D Porous Structure

In microfluidic related chemical and biological applications, mixing on the micro scale is important and has been considered as one of the most challenging tasks. With a trend for polymeric microfluidic systems, a simple yet efficient passive micromixer is highly preferred [1–4]. We developed a novel passive micromixer with 3D porous microstructure on a polymer chip. The fabrication process uses high-intensity focused ultrasound to selectively foam gas-impregnated polymers. The selective ultrasonic foaming technique is simple, low-cost, and biocompatible. The porous microstructure is easily controlled by adjusting the parameters of the ultrasonic foaming process. The 3D porous microstructure can split, stretch, fold and break the mixing flows in microfluidic channels and thus dramatically improve the mixing efficiency.