Research on an Off-Chip Microvalve for Pneumatic Control in Microfluidic Chips

Abstract

A compact, rapid, and portable off-chip pneumatic control valve is significant for the miniaturization and integration of external pneumatic systems for microfluidic chips. In this work, an off-chip microvalve with a high-speed electromagnetic switch actuator and a polydimethylsiloxane (PDMS) material valve body has been designed to be easily encapsulated, simulated using MATLAB/Simulink software, and tested in a micromixer. Multi-physical coupling mathematical models are developed based on the elastic deformation force of the valve membrane, the driving force of the valve core, and the fluid force in the microchannel. Two single microvalves are used to form a three-way microvalve, which can control the air pressure in a pneumatic microchannel on the microfluidic chip. The relationship between the flow–duty cycle, the flow–pressure difference of the single electromagnetic microvalve, and the load pressure of the three-way microvalve is simulated and analyzed. Sample mixing performance controlled by the proposed off-chip three-way microvalve was tested to evaluate the pneumatic control capability, and the results show that the undertaking can fully satisfy the needs of a pneumatic microfluidic chip for most applications.

Reversible Thermally-Responsive Copolymer Valve for Manipulating Water Wicking

“…This indicates the thermal response cyclability of N-PNAGA/PSt samples. In contrast to other kinds of valves, the as-prepared thermally responsive valves do not require complex and expensive external equipment, , and exhibit temperature-adaptive responsiveness, , and multicycle ability, , which shed some light on developing reversible responsive valves.…”

Actuation for flexible and stretchable microdevices

“…In addition, the time taken to recover the deformation of flexible membranes is another critical factor in the design of flexible membrane-based electromagnetic actuators. 116…”

“…In addition, the time taken to recover the deformation of flexible membranes is another critical factor in the design of flexible membrane-based electromagnetic actuators. 116 Magnetorheological (MR) fluid changes its apparent viscosity when exposed to a magnetic field. This phenomenon happens because the magnetic microparticle suspended in MR fluid aligns with the magnetic flux lines.…”

“…The actuation happens by the temperature-induced strain of the shape memory alloy (SMA), and the recovery motion occurs through the elastic forces of the capsule material acting as a spring. 116 (B) A Lorentz force-based shape morphing structure shows arbitrary shapes under selective current supply through liquid metal conductors. 111 (C) A magnetorheological (MR) fluid-based flexible actuator deforms under blockage of the fluid flow by magnetic particles that concentrated at the locally applied magnetic field.…”

“…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.…”