Microfabricated device

Abstract

A microfabricated device ( 10 ) includes a structure ( 12 ) defining a closed fluid delivery channel ( 14 ), the channel ( 14 ) having an inlet ( 16 ) and an opposed outlet ( 18 ). A conducting polymer actuator ( 20 ) is arranged within the fluid delivery channel ( 14 ). At least a part of the actuator ( 20 ) is configured to vary its cross sectional area in a direction transverse to a direction of fluid flow in the channel ( 14 ). An actuator control arrangement ( 22 ) is carried by the structure ( 12 ) for controlling the actuator ( 20 ) to cause the actuator ( 20 ) to expand and contract cyclically and sequentially along the length of the actuator ( 20 ) to vary the cross sectional area of the channel ( 14 ) cyclically and sequentially to effect a peristaltic pumping action to deliver fluid from the inlet ( 16 ) of the channel ( 14 ) to the outlet ( 18 ) of the channel ( 14 ).

1 . A microfabricated device which includes:
 a structure defining a closed fluid delivery channel, the channel having an inlet and an opposed outlet;   a conducting polymer actuator arranged within the fluid delivery channel, at least a part of the actuator being configured to vary its cross sectional area in a direction transverse to a direction of fluid flow in the channel; and   an actuator control arrangement carried by the structure for controlling the actuator to cause the actuator to expand and contract cyclically and sequentially along the length of the actuator to vary the cross sectional area of the channel cyclically and sequentially to effect a peristaltic pumping action to deliver fluid from the inlet of the channel to the outlet of the channel.   
   
   
       2 . The device of  claim 1  in which the structure includes a base and a pair of spaced side walls extending upwardly from the base, the side walls supporting a cover layer spaced from the base to define the channel. 
   
   
       3 . The device of  claim 2  in which the cover layer is applied by micromachining techniques. 
   
   
       4 . The device of  claim 2  in which the actuator is arranged in the channel between the side walls. 
   
   
       5 . The device of  claim 2  in which the actuator supports the cover layer in a spaced position relative to the base, a central part of the actuator being configured to vary its cross sectional area while side parts of the actuator function as side walls to support the base and the cover member in spaced relationship. 
   
   
       6 . The device of  claim 1  in which the actuator is a unitary, one-piece body. 
   
   
       7 . The device of  claim 1  in which the actuator is made up of a plurality of discrete actuator elements arranged in series in the channel. 
   
   
       8 . The device of  claim 1  in which the actuator control arrangement comprises an electrode array arrangement. 
   
   
       9 . The device of  claim 8  in which the electrode array arrangement comprises a plurality of electrode arrays to facilitate phased cyclic expansion and contraction of the actuator elements to effect the peristaltic pumping action. 
   
   
       10 . The device of  claim 8  in which the electrode array arrangement is deposited on the structure by a deposition technique 
   
   
       11 . The device of  claim 1  in which conducting polymers of the actuator are selected from the group consisting of polypyrrole and its derivatives, polyaniline and its derivatives, polythiophene and its derivatives poly(ethylenedioxythiphene), polyphenylene, poly(pheylenevinylidene) and its derivatives. 
   
   
       12 . The device of  claim 1  in which a fluid to be pumped by the device is an electrolyte which reduces and oxidises the actuator, the actuator being exposed to the electrolyte in the channel. 
   
   
       13 . The device of  claim 1  in which a membrane separates a fluid to be pumped through the device and an electrolyte in which the actuator is immersed. 
   
   
       14 . The device of  claim 13  in which the membrane is a polymer membrane. 
   
   
       15 . The device of  claim 12  in which the electrolyte is one of a liquid electrolyte, a polymer electrolyte, a polymer gel electrolyte and an ionic liquid. 
   
   
       16 . The device of  claim 15  in which the liquid electrolytes are aqueous and organic based solvents. 
   
   
       17 . The device of  claim 16  in which the liquid electrolytes contain supporting salts with either anion or cations being able to move in and out of the conducting polymer material. 
   
   
       18 . The device of  claim 17  in which the salts are low molecular salts selected from the group consisting of KCl, NaCl, KClO 4 , tetrabutylammonium hexafluorophosphate, tetrabutylammonium triflouromethanesulfonate. 
   
   
       19 . The device of  claim 17  in which the salts are surfactant type salts. 
   
   
       20 . The device of  claim 17  in which the salts are polyelectrolyte ionic liquids. 
   
   
       21 . The device of  claim 15  in which the polymer electrolytes and polymer gel electrolytes are poly methyl methacrylate/lithium perchlorate in a propolyene carbonate/acetonitrile mixture as a solvent. 
   
   
       22 . The device of  claim 1  in which the actuator is grown on the actuator control arrangement via electropolymerisation techniques or deposited on the substrate surface.