Electroosmotic devices

Abstract

Electroosmotic (EO) devices are provided which are not subject to mechanical wear and tear and with no moving parts, and having improved flow rates and electrical properties. Atomic layer deposition can be used to prepare three electrical terminal active zeta potential modulated EO devices from porous membranes. First, second, and further thin layers of materials can be formed with the pores. Thus, embedded electrodes can be formed along the length of the pores. The zeta potential in the pores can be modified by use of a voltage potential applied the embedded electrode, thereby achieving active control of surface zeta potential within the pores and active control of flow through the pores.

1 . An electroosmotic device comprising:
 a substrate comprising at least one pore extending from a first major surface of the substrate to a second major surface of the substrate, the at least one pore comprising one of a macropore, a micropore, or a nanopore;   at least one first material disposed on at least the inner surface of the at least one pore, wherein the at least one first material is electrically conductive,   at least one second material disposed at least on the at least one first material in the at least one pore, wherein the at least one second material is an electrical insulator,   at least one anode electrode adjacent to the first major surface; and   at least one cathode electrode adjacent to the second major surface.   
     
     
         2 . The device according to  claim 1 , wherein the at least one first material is in electrical communication with a first voltage source, independently biased from a second voltage source applying a voltage difference between the at least one cathode electrode and the at least one anode electrode. 
     
     
         3 . The device according to  claim 1 , the device further comprising a pump housing and at least two fluid chambers to provide inlet flow and outlet flow. 
     
     
         4 . The device according to  claim 1 , wherein the substrate comprises aluminum oxide or silicon. 
     
     
         5 . The device according to  claim 1 , wherein the at least one first material comprises at least one of metal, a metal alloy, a semiconductor, a conducting metal nitride, or a conducting oxide. 
     
     
         6 . The device according to  claim 1 , wherein the first material comprises at least one of Ti, Au, Pt, Al, Cu, Ag, W, nitride thereof, or ZnO 
     
     
         7 . The device according to  claim 1 , wherein the at least one second material comprises an oxide or metal oxide. 
     
     
         8 . The device according to  claim 1 , wherein the at least one second material comprises an oxide selected from the group consisting of HfO 2 , ZrO 2 , Al 2 O 3 , TiO 2 , or SiO 2 . 
     
     
         9 . The device according to  claim 1 , wherein the at least one first material has a thickness of at least 10 nm. 
     
     
         10 . The device according to  claim 1 , wherein an aspect ratio of the at least one pore is about 5 to about 1,200. 
     
     
         11 . The device according to  claim 1 , wherein the substrate is about 10 microns to about 200 microns thick. 
     
     
         12 . The device according to  claim 1 , wherein the at least one pore has a pore size that is between about 50 nm and about ten microns. 
     
     
         13 . The device according to  claim 1 , further comprising at least one electrically conductive mesh adjacent to the substrate and defining at least one of the at least one cathode electrode or the at least one anode electrode. 
     
     
         14 . A method of preparing an electroosmotic device comprising:
 obtaining a substrate comprising a first major surface, a second major surface, and at least one pore extending from the first major surface to the second major surface, the pore comprising one of a macropore, a micropore, or a nanopore;   forming at least one first material on at least the inner surface of the at least one pore, wherein the at least one first material is electrically conductive;   depositing at least one second material on at least one first material, wherein the second material is an electrical insulator; and   providing at least one anode electrode adjacent to the first major surface and at least one cathode electrode adjacent to the second major surface.   
     
     
         15 . The method of  claim 14 , wherein the step of forming comprises providing a thickness for the at least one first material of at least about 10 nm. 
     
     
         16 . The method of  claim 14 , wherein the step of forming comprises depositing at least one electrically conductive material on the at least the inner surface of the pores to define the at least one first material. 
     
     
         17 . The method of  claim 16 , wherein the at least one first material is deposited by atomic layer deposition (ALD). 
     
     
         18 . The method of  claim 17 , wherein the ALD is carried out at a deposition temperature of about 100° C. to about 350° C. 
     
     
         19 . The method of  claim 17 , wherein ALD is carried out for at least 300 ALD cycles. 
     
     
         20 . The method of  claim 17 , wherein the ALD is carried out with a dwell time adapted to avoid blocking the pores but provide conformal coverage. 
     
     
         21 . The method of  claim 14 , wherein the at least one second material is deposited by atomic layer deposition (ALD). 
     
     
         22 . The method of  claim 14 , wherein the step of providing the substrate further comprising selecting the substrate such that the at least one pore has an aspect ratio of about 300 to about 1,200. 
     
     
         23 . The method of  claim 14 , wherein the step of forming comprises implanting at least one dopant into the at least the inner surface of the pores to define the at least one first material. 
     
     
         24 . The method of  claim 14 , wherein the step of providing further comprises positioning at least one electrically conductive mesh adjacent to the substrate to define at least one of the at least one cathode electrode or the at least one anode electrode. 
     
     
         25 . A method for using an electroosmotic device comprising:
 providing an electroosmotic device comprising a substrate having at least one pore that is a macropore, a micropore, or a nanopore, at least one first material formed on the inner surface of the at least one pore, at least one second material disposed on the at least one first material, at least one anode electrode adjacent to a first major surface of the substrate, and at least one cathode electrode adjacent to a second major surface of the substrate, wherein the at least one first material is electrically conductive and the at least one second material is an electrical insulator;   applying a first voltage across the anode and cathode to generate electroosmotic flow through the at least one pore; and   applying a second voltage independently biased from the first voltage to the at least one first material to modify the electroosmotic flow.   
     
     
         26 . The method of  claim 25 , wherein the modification of electroosmotic flow is an increase in flow rate, a decrease in flow rate, or a reversal of flow. 
     
     
         27 . The method of  claim 25 , wherein the step of applying the first voltage comprises selecting the first voltage to be five volts or less. 
     
     
         28 . An electroosmotic device comprising:
 a substrate comprising at least one pore extending from a first major surface of the substrate to a second major surface of the substrate, the at least one pore comprising one of a macropore, a micropore, or a nanopore;   a plurality of dopant atoms embedded into at least the inner surface of the at least one pore to define at least one first material at the at least the inner surface of the at least one pore, the at least one first material being electrically conductive;   at least one second material disposed at least on the at least one first material in the at least one pore, wherein the at least one second material is an electrical insulator,   at least one anode electrode adjacent to the first major surface; and   at least one cathode electrode adjacent to the second major surface.   
     
     
         29 . The device according to  claim 28 , wherein the at least one first material is in electrical communication with a first voltage source, independently biased from a second voltage source applying a voltage difference between the at least one cathode electrode and the at least one anode electrode. 
     
     
         30 . The device according to  claim 28 , the device further comprising a pump housing and at least two fluid chambers to provide inlet flow and outlet flow. 
     
     
         31 . The device according to  claim 28 , wherein the substrate comprises aluminum oxide or silicon. 
     
     
         32 . The device according to  claim 28 , wherein the plurality of dopants comprise p-type or n-type dopants. 
     
     
         33 . The device according to  claim 28 , wherein the at least one second material comprises an oxide or metal oxide. 
     
     
         34 . The device according to  claim 28 , wherein the at least one second material comprises an oxide selected from the group consisting of HfO 2 , ZrO 2 , Al 2 O 3 , TiO 2 , or SiO 2 . 
     
     
         35 . The device according to  claim 28 , wherein the at least one first material has a thickness of at least 10 nm. 
     
     
         36 . The device according to  claim 28 , wherein an aspect ratio of the at least one pore is about 5 to about 1,200. 
     
     
         37 . The device according to  claim 28 , wherein the substrate is about 10 microns to about 200 microns thick. 
     
     
         38 . The device according to  claim 28 , wherein the at least one pore has a pore size that is between about 50 nm and about ten microns. 
     
     
         39 . The device according to  claim 28 , further comprising at least one electrically conductive mesh adjacent to the substrate and defining at least one of the at least one cathode electrode or the at least one anode electrode.