Porous materials and systems and methods of fabricating thereof

Abstract

A porous material with a specific surface area higher than 10/mm, and methods and system for manufacturing such a porous material. The porous material includes a plurality of pores having a substantially uniform size with a variation of less than about 20%, wherein the size is larger than about 100 nm and smaller than about 5 mm. A system including the porous material can be configured as one of a desalination system, a super-fine bubble generation system, a capacitor system, or a battery system.

1 . A porous material with a specific surface area higher than 10/mm, the specific surface area depending on different pore sizes, wherein the porous material comprises a plurality of pores having a substantially uniform size with a variation of less than about 20%, wherein the size is larger than about 100 nm and smaller than about 5 mm. 
     
     
         2 . The porous material of  claim 1 , wherein the porous material is substrateless membrane. 
     
     
         3 . The porous material of  claim 1 , comprising a plurality of grain boundary regions filled with a solid material to increase a mechanical strength of the porous material, wherein the specific surface area is higher than 4100/mm, wherein the size variation is less than about 10%, and wherein the grain boundary regions have a size of about 5 μm-15 cm. 
     
     
         4 . A system configured to fabricate a porous material, the system comprising:
 a particle template formation portion configured to fabricate a particle template;   an infiltration portion configured to infiltrate the particle template with an infiltrant substance, and   a template removal portion configured to remove the particle template and keep the infiltrant substance substantially intact, to thereby form a sub strateless porous material with a specific surface area higher than 10/mm, wherein the porous material comprises a plurality of pores having a substantially uniform size with a variation less than 20%, wherein the size is larger than about 100 nm and smaller than about 5 mm.   
     
     
         5 . The system of  claim 4 , further comprising a baking portion configured to dry the particle template fabricated through the particle template formation portion to thereby enhance mechanical strength of the colloidal particle template. 
     
     
         6 . The system of  claim 5 , wherein the particle template formation portion comprises an electrophoresis assembly apparatus including:
 an electrophoresis tank;   a DC power supply;   a magnetic stirrer;   a reference electrode; and   a working electrode; wherein:
 an electrophoresis solution containing a suspension of particles is disposed in the electrophoresis tank; 
 the reference electrode and the working electrode are substantially vertically arranged in the electrophoresis tank; and 
 the working electrode provides a surface for electrophoretically fabricating the particle template. 
   
     
     
         7 . The system of  claim 6 , wherein the reference electrode has a shape of a round rod and is disposed adjacent to an air-liquid interface or lower than the interface by about 0-5 cm. 
     
     
         8 . The system of  claim 7 , wherein the working electrode comprises a flexible and movable conductive tape, and a leak-proof inlet is arranged on a sidewall of the electrophoresis tank such that the flexible and movable conductive tape can be fed into the electrophoresis tank. 
     
     
         9 . The system of  claim 4 , wherein the infiltration portion comprises an electrophoretic deposition (EPD) apparatus including:
 an EPD tank;   a DC power supply;   a reference electrode; and   a working electrode; wherein:
 an EPD solution is placed in the EPD tank; and 
 the working electrode is configured to carry the colloidal particle template, the colloidal particle template providing a surface for electrophoretic deposition of the infiltrant substance on the colloidal particle template inside the EPD tank. 
   
     
     
         10 . The system of  claim 4 , wherein the template removal portion comprises a chemical etching apparatus including an etching tank having an etching solution disposed therein, whereby the particle template is removed by the etching solution to only keep the infiltrant substance. 
     
     
         11 . The system of  claim 10 , wherein a leak-proof inlet and a leak-proof outlet are arranged at sidewalls of the etching tank for leak-free feeding of a flexible and movable conductive tape carrying the colloidal particle template and the infiltrant substance into and out of the etching tank, respectively. 
     
     
         12 . The system of  claim 11 , further comprising a blade configured to separate the infiltrant substance from the flexible and movable conductive tape to obtain the porous material and to recycle the flexible and movable conductive tape. 
     
     
         13 . A method of fabricating a porous material, comprising:
 (1) fabricating, with a particle template formation portion, a particle template;   (2) infiltrating, with an infiltration portion, the particle template with an infiltrant substance; and   (3) removing, with a template removal portion, the particle template and keep the infiltrant substance intact to thereby form a substrateless porous material with a surface-area-to-volume ratio higher than about 10/mm, wherein the porous material comprises a plurality of pores having a substantially uniform size with a variation of less than about 20%, wherein the size is larger than about 100 nm and smaller than about 5 mm.   
     
     
         14 . The method of  claim 13 , further comprising baking the particle template immediately after the step (1) and before the step (2) to enhance mechanical strength of the particle template, wherein said baking is performed at a temperature of about 90-500° C., a relative humidity of >75, for a duration of about 0.5-2 hrs. 
     
     
         15 . The method of  claim 14 , wherein:
 an electrophoresis solution containing a suspension of colloidal particles is disposed in an electrophoresis tank;   a reference electrode and a working electrode are substantially vertically disposed in the electrophoresis tank;   the reference electrode has a shape of a round rod;   the working electrode provides a surface for electrophoretically fabricating the particle template; and   an electric field between the reference electrode and the working electrode is in a range of about 0.1 V/cm-1000 V/cm.   
     
     
         16 . The method of  claims 15 , further comprising providing the suspension of particles including a powder substance selected from at least one of polystyrene, SiO 2 , or PMMA, wherein the power substance has a particle size of about 100 nm-5 mm, and wherein the electrophoresis solution comprises an ionic solution configured to provide electrical charges to surfaces of the colloidal particles. 
     
     
         17 . The method of  claim 16 , wherein the electrophoresis solution comprises at least one of:
 an ethanol solution with a pH value of about 4-9, NH 4 OH/HNO 3 , or SDS.   
     
     
         18 . The method of  claim 17 , wherein the working electrode is static or configured to move at a speed of about 100 nm/sec-10 cm/sec. 
     
     
         19 . The method of  claim 13 , further comprising heating the particle template carrying the infiltrant substance to about 500° C. for less than 24 hours to thereby thermally remove the colloidal particle template while keeping the infiltrant substance substantially intact and oxidizing metal structure surfaces, wherein the particle template comprises polymers. 
     
     
         20 . The method of  claim 14 , further comprising chemically removing the particle template while keeping the infiltrant substance substantially intact and avoiding oxidizing metal structure surfaces, and wherein said chemically removing comprises etching at a temperature of about 40-80° C. for about 1-4 hours.