A novel electromagnetic micropump with PDMS membrane supported by a stainless-steel microstructure

Abstract

As a main component, membrane micropumps play a key role in developing microfluidic systems. This part pumps fluids by deflecting a membrane using a micro-actuator with a deflection range of a few micrometers during a few seconds. Most electromagnetic micropumps have low lifetime and fracture toughness or low recovery speed. Micropumps with metallic mass-spring structures can overcome the mentioned disadvantages or limitations. This study investigated the fabrication and characterization of a novel electromagnetic micropump. The proposed micropump consists of a stainless-steel mass-spring structure, a polydimethylsiloxane (PDMS) body and membrane, a permanent NdFeB magnet, a micro-coil, and a 3D printed spacer. To characterize the micropump, the effects of the frequency and duty cycle of the electric current applied to the micro-coil on the micropump flow rate and the membrane deflection vs. time were investigated. A membrane deflection of ±8 µm was obtained in 4 s by applying 1000 mA electrical current to the micro-coil. The maximum volumetric flow rate of 523 nL/s was obtained at a frequency of 125 mHz and a duty cycle of 50%. The von Mises stress distribution in the micropump membrane and variations of the fluid velocity in the microchannels were analyzed using the finite element method (FEM).

Actuation for flexible and stretchable microdevices

“…Some electromagnetic actuators utilise mass-spring structures that can be easily fabricated by the microwire electro-discharge machining. 112 Magnetic nanoparticle-suspended elastomeric materials can be synthesised through ultrasonication, giving rapid and uniform nanoparticle dispersion compared with high-speed shear mixing. 117 These elastomers are then spin-coated to fabricate the flexible magnetic responsive actuators through a layer-by-layer approach.…”

“…Magnetic actuators use the potential energy of the magnetic fields to produce mechanical motion. 109 The working principles of magnetic actuators are based on permanent magnets, 110 electromagnets, 111,112 magnetorheological fluid, 113 magnetic hydrogel, 44 magnetic shape memory materials, 114 and magnetostriction. 115 Among these schemes, the most straightforward is utilising attractive and repulsive forces between permanent magnets.…”

“…This journal is © The Royal Society of Chemistry 2024 electromagnets, 111,112 magnetorheological fluid, 113 magnetic hydrogel, 44 magnetic shape memory materials, 114 and magnetostriction. 115 Among these schemes, the most straightforward is utilising attractive and repulsive forces between permanent magnets.…”

“…Magnetic microactuators also utilise membranes 111,112,116 and flexible structures 113,117,118 for actuation purposes. Attractive and repulsive forces generated by an electromagnetic coil deflect the flexible membranes attached to permanent magnets.…”

“…Attractive and repulsive forces generated by an electromagnetic coil deflect the flexible membranes attached to permanent magnets. 112 For example, Liu et al 116 developed a normally closed microvalve using an electromagnetic coil surrounding a ferromagnetic core, Fig. 3A.…”