PDMS Membrane with Integrated Nozzle-Diffuser Structure for Peristaltic Pumping of Fluids in Microfluidic Structures

In this contribution we present a concept, where a tiny nozzle-diffuser structure is directly integrated into the center of a flexible poly(dimethylsiloxane) (PDMS) membrane, which is placed into a small fluid cavity with symmetric inlet and outlet geometry. The actuation of the membrane is achieved with an electromagnetic coil from the outside and a small magnetic ring, which has also been integrated into the membrane. The sinusoidal excitation leads to a vibrational movement of the membrane in the fluid cavity, and due to the asymmetric hydrodynamic resistance of the cone-shaped opening in the center of the membrane, which essentially resembles a nozzle-diffuser structure, a unidirectional fluid flow evolves in the system. This pump mechanism can be further miniaturized and integrated into microfluidic systems. In this paper we present details on the device concept, we report on the fabrication procedure, and we show experimental results with a first functional prototype.