Patent Application
20120129682
This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Applications No. 10-2010-0116816, filed on Nov. 23, 2010, the entire contents of which are hereby incorporated by reference.
The present disclosure herein relates to a method of fabricating a nanowire porous medium and to a nanowire porous medium fabricated by the method.
Nanowires have larger surface area than typical materials such that nanowires have excellent absorption capacity with respect to materials such as gases, ions and atoms and can selectively absorb specific materials by surface treatment. Based on these advantages, many researches and developments are being actively progressed in order to apply nanowires to high functional•high efficiency filter materials, energy storage media materials, reinforcing agents of composite materials or the like by recently fabricating the nanowires into a film of more than few cm or a structure having a three-dimensional shape.
However, in spite of having many advantages as described above, products applied with the nanowires have not come into wide use because of complex manufacturing processes, low durability and high-priced materials.
The present disclosure provides a method of fabricating a nanowire porous medium which can be fabricated by easier and simpler processes.
The present disclosure also provides a nanowire porous medium having excellent functionality and durability.
Embodiments of the inventive concept provide methods of fabricating a nanowire porous medium including: preparing a nanowire solution and a polymer solution, respectively; mixing the nanowire solution with the polymer solution to form a first mixed solution; mixing and stirring water and an organic solvent to form a second mixed solution including a large amount of bubbles; mixing and stirring the first and second mixed solutions to form a third mixed solution; and forming a nanowire porous medium by freeze-drying the third mixed solution.
In some embodiments, the above method may further include performing a surface treatment process with respect to the nanowire porous medium. The performing of the surface treatment process may use plasma.
In other embodiments of the inventive concept, a nanowire porous medium includes a polymer and nanowires. In one example, the nanowire porous medium according to the inventive concept includes a vanadium pentoxide (V2O5) and polyvinyl alcohol.
The accompanying drawings are included to provide a further understanding of the inventive concept, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain principles of the inventive concept. In the drawings:
Preferred embodiments of the present invention will be described below in more detail. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.
Referring to
Continuously, referring to
Continuously, referring to
Continuously, in fourth step S40, water and organic solvent are mixed and stirred to form a second mixed solution including bubbles. The organic solvent may be at least one selected from the group consisting of acetic acid (C2H4O2), aceton (C3H6O), acetonitrile (C2H3N), benzene (C6H6), 1-butanol (C4H10O), 2-butanol (C4H10O), 2-butanone (C4H8O), t-butyl alcohol (C4H10O), carbon tetrachloride (CCl4), chlorobenzene (C6H5Cl), chloroform (CHCl3), cyclohexane (C6H12), 1,2-dichloroethane (C2H4Cl2), diethyl ether (C4H10O), diethylene glycol (C4H10O3), diglyme (C6H14O3), 1,2-dimethoxy-ethane (C4H10O2), dimethylether (C2H6O), dimethyl-formamide (DMF, C3H7NO), dimethyl sulfoxide (DMSO, C2H6OS), dioxane (C4H8O2), ethanol (C2H6O), ethyl acetate (C4H8O2), ethylene glycol (C2H6O2), glycerin (C3H8O3), heptane (C7H16), hexamethylphosphoramide (HMPA, C6H18N3OP), hexamethylphosphorous triamide (HMPT, C6H18N3P), hexane (C6H14), methanol (CH4O), methyl t-butyl ether (MTBE, C5H12O), methylene chloride (CH2Cl2), N-methyl-2-pyrrolidinone (NMP, CH5H9NO), nitromethane (CH3NO2), pentane (C5H12), petroleum ether (ligroine), 1-propanol (C3H8O), 2-propanol (C3H8O), pyridine (C5H5N), tetrahydrofuran (THF, C4H8O), toluene (C7H8), triethyl amine (C6H15N), o-xylene (C8H10), m-xylene (C8H10), and p-xylene (C8H10). The fourth step may be performed using a stirrer and/or a mixer.
Continuously, in fifth step S50, the first mixed solution and the second mixed solution are mixed to form a third mixed solution.
Then, in sixth step S60, a nanowire porous medium is formed by freeze-drying the third mixed solution. For this purpose, the third mixed solution is first put into a container and a freeze-drying process may be performed. The nanowire porous medium may have various shapes depending on the shapes of the container. For example, the nanowire porous medium may have a shape like a film or a bulk. The step of the freeze-drying of the third mixed solution may be performed under a pressure of about 0-10 mTorr. Therefore, the nanowire porous medium including the nanowires and the polymer may be formed by removing solvent in the third mixed solution.
Subsequently, in seventh step S70, surface treatment may be performed on the nanowire porous medium in order to selectively attach a radical having a property like hydrophilic or hydrophobic. The surface treatment may be performed using plasma.
Referring to
First step: First, a nanowire solution was prepared. About 0.4 g of ammonium meta-vanadate (NH4VO3) was prepared as nanowires. After putting 0.4 g of ammonium meta-vanadate (NH4VO3) and 4 g of an ion-exchange resin into about 80 ml of distilled water, they were mixed sufficiently using a stirrer. Although it showed a yellow color in the beginning, the solution of vanadium pentoxide nanowire having a reddish-brown color was prepared after 72 hours.
Second step: A polymer solution was prepared. About 2 g of polyvinyl alcohol was prepared as a polymer. After mixing this with about 98 ml of distilled water, they are sufficiently mixed for about 1 hour using the stirrer at 60° C. Although it showed a white color in the beginning, the polymer solution of polyvinyl alcohol having clear color was prepared after about 1 hour.
Third step: a first mixed solution was prepared by mixing about 100 ml of the nanowire solution with about 100 ml of the polymer solution and stirring for about 1 hour with the stirrer.
Fourth step: a second mixed solution was prepared by mixing about 90 ml of distilled water with about 10 ml of tetrahydrofuran (THF). The second mixed solution was sufficiently mixed for about 30 minutes using the stirrer and a mixer in order to form a large amount of bubbles in the second mixed solution.
Fifth step: a third mixed solution was made by mixing about 200 ml of the first mixed solution with about 100 ml of the second mixed solution for about 30 minutes by the stirrer and the mixer.
Sixth step: the third mixed solution was put into a container having a circular shape such as a chalet, and put the container in a refrigerator maintaining at about 5° C. to freeze. Then, it was frozen for about 1 day. The container was put in a freeze-dryer maintaining at a temperature of about −80° C. and a nanowire porous medium containing vanadium pentoxide (V2O5) and polyvinyl alcohol was fabricated by drying.
The surface treatment of the seventh step was not performed in the present exemplary embodiment.
The nanowire porous medium fabricated according to the present exemplary embodiment is shown in
Referring to
Meanwhile, a comparative experiment was performed to examine effects caused by an addition of organic solvent in the fabricating method of the nanowire porous medium according to the inventive concept. In the comparative experiment, THF, which was the organic solvent in the above exemplary embodiment, was not added, and the rest processes were the same as the exemplary embodiment.
A portion of a nanowire porous medium fabricated according to a comparative example is enlarged and shown in
Referring to
The nanowire porous medium containing vanadium pentoxide (V2O5) and polyvinyl alcohol, which was fabricated in the present exemplary embodiment, has excellent absorption capacity and durability in particular.
Likewise, a nanowire porous medium can be easily fabricated to a desired shape and size by the fabricating method of the nanowire porous medium according to the inventive concept. Also, the nanowire porous medium according to the inventive concept includes nanowires having a large surface area and a polymer having excellent durability, thereby enabling to be used in real life as filters or absorbents for removing contaminants or used in variety for the purposes of energy storage and structural reinforcement of composites, etc.
In a fabricating method of a nanowire porous medium according to the inventive concept, water and organic solvent are mixed and stirred to form a large amount of bubbles, and the bubbles are used such that porosity can be formed more easily and in a large quantity. Therefore, the nanowire porous medium can be fabricated more easily and simply. Also, the nanowire porous medium according to the inventive concept contains the nanowires that increase absorption capacity, and the polymer that increases flexibility and durability.
The above-disclosed subject matter is to be considered illustrative and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the inventive concept. Thus, to the maximum extent allowed by law, the scope of the inventive concept is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2010-0116816 | Nov 2010 | KR | national |
