Electroosmotic pump

Abstract

Provided is a novel electroosmotic pump capable of being driven by AC voltage. An electroosmotic pump ( 2 ) includes a porous dielectric membrane ( 21 ), a first water-permeable electrode ( 22 ), and a second water-permeable electrode ( 23 ). The first water-permeable electrode ( 22 ) is disposed on one side of the porous dielectric membrane ( 21 ). The second water-permeable electrode ( 23 ) is disposed on the other side of the porous dielectric membrane ( 21 ). A principal surface of the porous dielectric membrane ( 21 ) close to the first water-permeable electrode ( 22 ) and a principal surface thereof close to the second water-permeable electrode ( 23 ) have mutually different hydrophilicities.

1 . An electroosmotic pump comprising:
 a porous dielectric membrane;   a first water-permeable electrode disposed on one side of the porous dielectric membrane; and   a second water-permeable electrode disposed on the other side of the porous dielectric membrane,   wherein a principal surface of the porous dielectric membrane close to the first water-permeable electrode and a principal surface of the porous dielectric membrane close to the second water-permeable electrode have mutually different hydrophilicities.   
     
     
         2 . The electroosmotic pump according to  claim 1 , wherein the porous dielectric membrane includes a hydrophilic layer on one of the principal surfaces. 
     
     
         3 . An electroosmotic pump comprising:
 a porous dielectric membrane;   a first water-permeable electrode disposed on one side of the porous dielectric membrane; and   a second water-permeable electrode disposed on the other side of the porous dielectric membrane,   wherein one surface of the porous dielectric membrane and the other surface of the porous dielectric membrane have mutually different zeta potentials or mutually different streaming potentials.   
     
     
         4 . An electroosmotic pump comprising:
 a porous dielectric membrane;   a first water-permeable electrode disposed on one side of the porous dielectric membrane; and   a second water-permeable electrode disposed on the other side of the porous dielectric membrane,   wherein the porous dielectric membrane is configured so that when an AC voltage is applied between the first water-permeable electrode and the second water-permeable electrode, a liquid in the porous dielectric membrane is given a force to selectively move from one of the side close to the first water-permeable electrode and the side close to the second water-permeable electrode to the other side.   
     
     
         5 . The electroosmotic pump according to  claim 1 , wherein
 the porous dielectric membrane includes a first porous dielectric membrane and a second porous dielectric membrane which are stacked on each other,   one of the principal surfaces of the porous dielectric membrane is formed by the first porous dielectric membrane, and   the other principal surface of the porous dielectric membrane is formed by the second porous dielectric membrane.   
     
     
         6 . The electroosmotic pump according  claim 1 , further comprising a power source operable to apply an AC voltage between the first water-permeable electrode and the second water-permeable electrode, wherein the power source is configured to apply an AC voltage with a frequency of 1 MHz or less. 
     
     
         7 . The electroosmotic pump according  claim 1 , wherein the porous dielectric membrane has a thickness in a range of 5 μm to 100 μm. 
     
     
         8 . The electroosmotic pump according to  claim 1 , wherein a ratio of the area of the water-permeable electrode to the square of thickness of the porous dielectric membrane ((the area of the water-permeable electrode)/(the thickness of the porous dielectric membrane) 2 ) is more than 100. 
     
     
         9 . The electroosmotic pump according to  claim 1 , wherein the porous dielectric membrane has an average pore diameter in a range of 10 nm to 50 μm. 
     
     
         10 . The electroosmotic pump according to  claim 1 , wherein each of the first and second water-permeable electrodes has a through hole passing through the water-permeable electrode in a thickness direction thereof. 
     
     
         11 . The electroosmotic pump according to  claim 1 , wherein the porous dielectric membrane has a through hole passing through the porous dielectric membrane in a thickness direction thereof. 
     
     
         12 . The electroosmotic pump according to  claim 1 , wherein
 the principal surface of the porous dielectric membrane close to the first water-permeable electrode has a higher hydrophilicity than the principal surface of the porous dielectric membrane close to the second water-permeable electrode, and   the first water-permeable electrode includes a hydrophilic layer as a surface layer on the side opposite to the porous dielectric membrane.