Patent EP-2161449-A1 (EP)
Inventor: FAJOLLE DAMIEN
IPC: B01L3/00
Filed: 2009-09-07
Abstract: The micropump for moving a first fluid (31) in a microchannel (10), comprises a chamber comprising an axial area (41) laid along the longitudinal axis of the microchannel and a lateral area (42), an inclusion of a second fluid engaging partially in the lateral area of the chamber, an electrical unit to provide a portion of the inclusion in the axial area in effect of electrical control comprising number of actuation electrodes arranged in the axial area of the chamber, and a unit for successive activation of actuation electrode to move the portion of the inclusion along the longitudinal axis. The micropump for moving a first fluid (31) in a microchannel (10), comprises a chamber comprising an axial area (41) laid along the longitudinal axis of the microchannel and a lateral area (42), an inclusion of a second fluid engaging partially in the lateral area of the chamber, an electrical unit to provide a portion of the inclusion in the axial area in effect of electrical control comprising number of actuation electrodes arranged in the axial area of the chamber, and a unit for successive activation of actuation electrode to move the portion of the inclusion along the longitudinal axis of the microchannel to cause the flow of the first fluid along the longitudinal axis of the microchannel. The unit for successive activation comprises a unit for electrical switch to enable and disable each actuation electrode, where the switch is controlled by a control unit. The portion of the inclusion is a local deformation of the inclusion, and covers an actuation electrode along the transverse section of the axial area. The chamber comprises a wall laid between the axial area and the lateral area on a portion of the length of the chamber so that the lateral area forms a secondary channel communicating with the axial area in upstream and downstream of the wall. The portion of the inclusion is optionally a secondary inclusion separated from inclusion by the wall. The first fluid is a dielectric fluid, and the second fluid is a conductive liquid, and vice-versa. The electrical unit for supplying the portion in the axial area comprises a counter-electrode electrically contacting with the inclusion, a voltage generator for applying a potential difference between the actuating electrodes and the counter-electrode, and an electrode for containment extending over the surface of the lateral area of the chamber. A second substrate is arranged for forming hood of the micropump. A second actuation electrode is incorporated in the hood and laid in the axial area of the chamber with respect to the first actuation electrode. The first fluid has an electrical permittivity inferior to that of the second fluid. The chamber comprises two lateral parts arranged next to one another each housing a drop of conductive liquid. A second substrate is arranged for forming hood of the micropump. Distance separating the first substrate and the hood in the chamber is significantly lower than the dimension of the chamber according to the median plane of the first substrate. The axial area has a width of less than its length. The spacing of inter-electrodes of actuation has a curved or angular form. The electrodes are coated with a hydrophobic material layer. The conductive liquid comprises zwitterionic species. A layer of dielectric material is arranged between the hydrophobic layer and the electrodes. The actuation electrodes are arranged in the matrix form.