Micro-Flow Control and Micropump by Applying Electric Fields through a Porous Membrane

Abstract

Experiments of micro-flow control and micropump conducted by applying electric fields on the flow through a porous membrane have clarified that only NaCl solution in water is effective for the control of micro-flow among the liquids examined but KCl solution and a colloidal dispersion of polystyrene latex particles in water as well as NaCl solution are good as working fluids for the micropump. Although the applied voltages are less than 10 V, performance of the present micropump is found belonging to the highest class in the past methods. Effects of electro-osmosis, electrophoresis and absorption were discussed about whether or not they may become causes of the present phenomena and it is concluded that absorption is most possible as a cause. The colloidal dispersion of polystyrene latex particles is thought to be a good working liquid, because it provides the flow rate proportional to the applied voltage without generating any bubble of by-product.

Electrochemical deposition of metal ions in porous laser sintered inter‐metallic and ceramic preforms

“…Certain undesirable chemical changes can be produced by the electrolyte or gases trapped inside, but these can be driven out of the structure just by heating the preform at a temperature of about 200-300 C. The transport of ions inside the porous structure depends on a number of factors such as their concentration in the electrolyte, ionic mobility and crystal radius and diffusion coefficient (Hasegawa, 2004). …”

Moving-part-free microfluidic systems for lab-on-a-chip

“…The differential pressure produced between the channels is the highest among the currently available micropumps, in the range of 0.1-1 atm. With the application of porous frit or nanoporous structures for the channel wall, or packing of nanoparticles in the channel, EO pumps with differential pressure up to 20 atm have been developed [25][26][27], which is suitable for high volumetric pumping. The voltage used for EO micropumps is in the range of a few tens of volts and increases up to 1.5 kV for those with high differential pressure.…”

Electrorheological fluid-actuated microfluidic pump

“…Various types of pumps have been designed and fabricated using different mechanisms, e.g., gas pump is actuated and controlled by gas 6,7 and piezoelectric transducer actuator pump utilizes electrical/ mechanical energy conversion. 8 There is also the electroosmosis pump 9 for pumping ionic solutions, e.g., NaCL and KCL. Here we present an application of the electrorheological ͑ER͒ fluid in the design and fabrication of a micropump, with programmable digital control.…”