Micro-flow control and micropump by applying electric fields through a porous membrane

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.