Abstract: A method and apparatus for moving droplets passed a porous obstructions in microfluidic devices is presented. The invention describes the process of using of an enabling droplet to allow a droplet to pass an obstruction. The enabling droplet and the unfiltered droplet approach the obstruction from opposite sides, merge together within the obstruction, and the interface on the enabling side of the droplet is actuated to pull fluid through the obstruction. This technique was successful for filters with pore sizes between 2 ?m and 72 without the use of surfactants. This invention can (1) move droplets past physical obstructions, (2) allow fluid within a particle to pass an obstruction while limiting the motion of man-made or biological particles within the droplet, (3) sort particles based on size in droplet-based microfluidic devices, or (4) provide an interface between continuous and discrete flow regions on a microfluidic device.

Abstract: The present invention relates to electrospray emitters that have a rigid substrate layer, a second layer, a channel formed in one of the rigid substrate layer and an exit orifice in flow communication with the channel. The second layer is attached to the first layer. The exit orifice is capable of holding an electric charge. The electrospray emitter may be used with such devices as a mass spectrometer, a colloidal thruster or an ion mobility device. Additionally, it may be used to coat a surface.

Abstract: An electrostatic actuator comprising: first and second comb arrays of electrodes arranged on a base, the electrodes of the first and second comb arrays being interleaved; a third comb array of electrodes spring mounted over the first and second comb arrays, the electrodes of the third comb array being essentially aligned with the electrodes of the second comb array; means for applying a first voltage to the third comb array and a second voltage to the first and second comb arrays to generate an attractive force acting on the third comb array to move the third comb array toward the second comb array; and, means for applying the first voltage to the second and third comb arrays and the second voltage to the first comb array to generate a repulsive force acting on the third comb array to move the third comb array away from the second comb array.

Abstract: The present invention relates to electrospray emitters that have a rigid substrate layer, a second layer, a channel formed in one of the rigid substrate layer and an exit orifice in flow communication with the channel. The second layer is attached to the first layer. The exit orifice is capable of holding an electric charge. The electrospray emitter may be used with such devices as a mass spectrometer, a colloidal thruster or an ion mobility device. Additionally, it may be used to coat a surface.

Abstract: An electrostatic actuator comprising: first and second comb arrays of electrodes arranged on a base, the electrodes of the first and second comb arrays being interleaved; a third comb array of electrodes spring mounted over the first and second comb arrays, the electrodes of the third comb array being essentially aligned with the electrodes of the second comb array; means for applying a first voltage to the third comb array and a second voltage to the first and second comb arrays to generate an attractive force acting on the third comb array to move the third comb array toward the second comb array; and, means for applying the first voltage to the second and third comb arrays and the second voltage to the first comb array to generate a repulsive force acting on the third comb array to move the third comb array away from the second comb array.