KR100619354B1 - Nano particle filter using aluminum anodizing oxide template and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a nano-granular filter using an anodized aluminum template and a method for manufacturing the same, and to a nickel-filled layer formed by removing the anodized film after performing nickel plating on the top thereof using a common anodized aluminum template. It provides a nano-granular filter using anodized aluminum oxide template and a method of manufacturing the same.

The nano-granular filter according to the present invention can arbitrarily adjust the gap and the size of the nickel filling layer has the advantage of selectively filtering particles having anisotropic structure as well as particles having anisotropic structure.

Aluminum Anodized, Template, Nano Granular Filter, Nickel Plated, Nickel Filled Layer, Anisotropic, Isotropic

Description

Nano particle filter using aluminum anodizing oxide template and manufacturing method

1a to 1e are views for explaining the manufacturing process of the anodized aluminum template according to the prior art.

Figure 2 is a scanning electron microscope (SEM) picture (x500) showing the pore structure of the aluminum oxide template according to the prior art.

3A to 3D are views for explaining a manufacturing process of the nanoparticle filter according to an embodiment of the present invention.

※ Explanation of code about main part of drawing ※

100: aluminum substrate 110: anodized film

120: pore 130: nickel plated layer

130a, 130a`: upper nickel layer 130b, 130b`: nickel filled layer

The present invention relates to a nano particulate filter using an anodized aluminum template and a method of manufacturing the same. More specifically, the present invention relates to a nano-granular filter capable of selectively filtering particles having an anisotropic structure, particles having an isotropic structure, and the like, using a common aluminum anodized template, and a method of manufacturing the same.

Anodized aluminum oxide (hereinafter referred to as AAO) refers to an aluminum substrate in which nanometer-sized pores (30-100 nm) are regularly arranged on an oxidized aluminum surface by anodizing aluminum. The AAO is used as a framework for making nanostructures such as nanotubes or nanowires, and the AAO template itself may be used as a nanomask.

This aluminum anodization technology has a long history. Already in 1923 a technique has been reported for anodizing the surface of commercial aluminum for the purpose of protection and decoration of the inner aluminum. Structures containing nanopores spontaneously generated during anodization are also widely known under the commercial name alumite.

Recently, as industrial demands and interests on nanostructures have increased, research on fine multilayered structures, nanowires, nanoparticles, and the like has been actively conducted, and electrochemical manufacturing methods for these nanostructures are economical and cost effective. Its simplicity and flexibility for complex geometries are emerging.

In line with this research, AAO is an aluminum oxide film that is anodized in a strong acid atmosphere and has recently been newly illuminated because of its porous material having nanopores with high regularity and anisotropy.

The pore diameter can be adjusted by controlling the anodization variable from 5nm to 300nm, and the length is from 1㎛ to 50㎛, and the density of the pores can also be made of high density nanowire with 10 ⁹ ~ 10 ¹¹ ㎝ ^-2 Template material. In particular, the nanopores are arranged in a relatively regular and almost parallel to the ideal template for the electrochemical production of nanowires having anisotropy.

At present, the structure and formation of AAO has not been clearly established and much research is being carried out as it is attracting attention as a template material for nanowires. When current flows to the aluminum anode in the electrolyte, an initial barrier layer of Al ₂ O ₃ is formed. At this time, if the voltage is sufficient, the film is locally destroyed and heat is generated. This heat accelerates more local erosion resulting in a microporous coating and current. At this time, Keller et al.'S explanation that the generated oxygen combines with Al inside to form a new boundary layer and the film grows by repeating this process several times is convincingly accepted. Keller et al. Said that a regular hexagonal cell was formed, and one nanopore existed at the center thereof, and the pore diameter was determined according to the electrolyte.

In this regard, the manufacturing process of the anodized aluminum template according to the prior art with reference to Figures 1a to 1e as follows.

First, the surface of the high purity aluminum substrate 10 having a predetermined thickness is mirror polished by electropolishing (see FIG. 1A).

Next, the mirror polished aluminum substrate 10 is subjected to first anodization using an electrolyte to form an AAO film 20 having nanopores 30 (see FIG. 1B).

This is etched in a conventional basic solution such as NaOH to remove the initial oxide film 20 (negative oxide) and to form the etching portion 40 (see Fig. 1c).

Next, for example, after fixing the type and concentration of the electrolyte by using an electrolyte such as sulfuric acid, while controlling the characteristics of the nano-pores 60 of the AAO membrane 50 by adjusting variables such as temperature and anodization voltage 2 Secondary anodization is performed (see FIG. 1D). At this time, the thickness of the AAO, that is, the length of the nanopores 60 is determined by the anodization time.

Finally, this is caused by partial dissolution using some acid solution known as a widening solution to widen the diameter of the nanopores 60 formed in the oxide film 50 and thus the length of the pores 60 and the oxide film 50. AAO having various diameters is manufactured under the same properties as in FIG. 1 (see FIG. 1E).

The scanning microscope photograph (* 500) of the AAO template which has a pore structure produced from this is shown in FIG.

Meanwhile, the AAO template may be used to manufacture nanowires by filling materials such as metals, ceramics, and polymers in the pores according to application purposes while controlling the size of the pores to be formed. The nanodevices using the nanowires may be applied to ultra-high direct hard disks, highly integrated memory devices, various electronic devices, and biochip devices.

In addition, the AAO template may be used as a nano-granular filter by controlling the size of the pores through the final cross section process and aluminum etching process. However, in the case of the nano-granular filter fabricated using the AAO template directly, the filter is clogged by the liquid due to the capillary phenomenon caused by the large aspect ratio, and isotropic with the anisotropic particles. The disadvantage was that the particles could not be filtered selectively.

Accordingly, in the present invention, as a result of extensive research to solve the above problems, by using a conventional aluminum anodized template to perform nickel plating in the upper and pores of the anodized film having excellent filtering characteristics Nano granular filters could be produced, and the present invention was completed based thereon.

Accordingly, an object of the present invention is to provide a nano-granular filter using an anodized aluminum template and a method for producing the same, which can selectively filter particles having an anisotropic structure, particles having an isotropic structure, and the like as needed.

Another object of the present invention is to provide a nano-granular filter using an anodized aluminum template and a method for manufacturing the same, which can easily change the filter size as desired in order to filter particles having a desired shape and a predetermined particle size range as needed. have.

According to an aspect of the present invention for achieving the above object,

(a) Anodic Aluminum Oxide (AAO) in which anodized film having a plurality of nano-sized pores is formed on the aluminum substrate by performing electro-polishing, anodizing, and etching processes on the aluminum substrate. ) Providing a template;

(b) performing nickel plating on the top of the AAO template to fill nickel in the plurality of pores and simultaneously form a nickel layer on the top of the AAO template; And

(c) depositing the AAO template in an anodized etching solution to remove the anodized film on the aluminum substrate;

Provided is a method for producing a nano particulate filter comprising a.

Here, the anodized film etching solution is preferably selected from the group consisting of a phosphoric acid solution, sulfuric acid solution, chromic acid solution, hydroxyl solution and a mixture solution thereof.

In the present invention is also prepared by the method according to the above aspect,

Top nickel layer;

Bottom aluminum substrate; And

A plurality of pillar-shaped nickel filling layers orthogonal to the nickel layer and spaced at a predetermined interval therebetween;

There is provided a nano particulate filter comprising:

According to another aspect of the invention,

(a) electrolytic polishing, anodizing and etching an aluminum substrate to provide a conventional AAO template having an anodized film having a plurality of nanosized pores formed on the aluminum substrate;

(b) performing nickel plating on the top of the AAO template to fill nickel in the plurality of pores and simultaneously form a nickel layer on the top of the AAO template;

(c) depositing the AAO template in an anodized etching solution to remove the anodized film on the aluminum substrate; And

(d) stacking and fixing the at least one pair of structures obtained in step (c) such that each nickel filling layer is disposed to cross each other;

Provided is a method for producing a nano particulate filter comprising a.

Here, the anodized film etching solution is preferably selected from the group consisting of a phosphoric acid solution, sulfuric acid solution, chromic acid solution, hydroxyl solution and a mixture solution thereof.

In the present invention it is also prepared by the method according to the other aspect,

Top nickel layer;

Bottom aluminum substrate; And

A plurality of pillar-shaped nickel filling layers orthogonal to the nickel layer and spaced at a predetermined interval therebetween;

At least a pair of structures having a nano-granular filter is provided, characterized in that each of the nickel filling layer is stacked so as to cross each other.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

3A to 3D are views for explaining a manufacturing process of the nanoparticle filter according to an embodiment of the present invention.

According to the present invention, first, an anode having a plurality of nanopores 120 on an aluminum substrate 100 by electrolytic polishing, anodizing, and etching the aluminum substrate 100 according to a conventional AAO template manufacturing method. An oxide film 110 is formed (see FIG. 3A).

The method of manufacturing the AAO template is not particularly limited as long as it is a method known by those skilled in the art, but will be described with reference to (1) to (4) described below for the purpose of illustration.

(1) electrolytic polishing

Sulfuric acid, phosphoric acid, and DI (Deionized Water) are mixed in a volume ratio of 2: 2: 3, and an aluminum substrate is added thereto, followed by electropolishing using a constant current method (20mA / cm 2).

(2) anodization

Anodizing is performed for 10 to 20 minutes using 0.3 MH ₃ PO ₄ using a carbon electrode on the cathode and an aluminum substrate electrolytically polished on the anode.

(3) etching

Anodized aluminum plate group is soaked in 0.5MH ₃ PO ₄ solution for 30-40 minutes to widen the pores of porous alumina.

(4) final sample cross section

The final sample is cross cut to complete an AAO template having an anodized coating with nanosized tubular pores.

Next, nickel plating is performed on the top of the conventional AAO template manufactured as described above, thereby filling the nickel 130 in the plurality of nanopores 120 and forming a nickel layer 130 on the top thereof (see FIG. 3B). .

In this case, the nickel plating is not particularly limited as long as it is a plating method known by a person of ordinary skill in the art, but preferably a current density of about 0.1 to 0.5ASD and a plating time of 30 while maintaining a plating temperature of about 50 ° C. It is preferably carried out under plating conditions of about 1 minute to about 1 hour. At this time, it is preferable to use a well-known watt bath (NiSO ₄ 135g / L, NiCl ₂ 22.5g / L, H ₃ BO ₃ 17.5g / L) as the plating solution.

Next, the AAO template is deposited on the anodizing film etching solution to remove the anodizing film 110 on the aluminum substrate 100 (see FIG. 3C).

In this case, as the anodized film etching solution, a 0.3 to 0.4 M phosphoric acid (H ₃ PO ₄ ) solution, a dilute sulfuric acid solution, a chromic acid solution, an aqueous solution, and a mixed solution thereof may be used.

Nano-granular filter according to an aspect of the present invention manufactured through the process as described above, as shown in Figure 3c, (i) the top nickel layer (130a), (ii) the bottom aluminum substrate 100, and (Iii) A plurality of pillar-shaped nickel filling layers 130b orthogonal to the nickel layer 130a and the aluminum substrate 100 and spaced at a predetermined interval therebetween.

Here, particles of various particle diameters can be filtered as desired by controlling the separation distance of the nickel filling layer 130b and the thickness of the filling layer 130b itself through the above-described etching process during fabrication of AAO. .

Further, according to another aspect of the present invention, by overlapping and fixing the at least one pair of nano-granular filter structures formed as described above so that the nickel filling layers 130b and 130b` are disposed to cross each other, as shown in FIG. 3D. And nickel filling layers 130b and 130b` between the nickel layers 130a and 130a` and the aluminum substrates 100 and 100` which are formed to face the upper and lower ends 130a and 100 and both sides 100 and 130a, respectively. They are arranged to intersect with each other to provide nano-granular filters that can perform finer and more precise filtering.

Here, by varying the distance between the nickel filling layer (130b, 130b`) and the size of the filling layer (130b, 130b`) itself freely through the above-described etching process during manufacturing AAO, various particle diameters as desired You can filter the particles of. In addition, when manufacturing and arranging each AAO template so that the final filter has a square filtering hole, there is an advantage of selectively filtering particles having anisotropic structure and particles having an isotropic structure.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, and the nano-granular filter using the AAO template according to the present invention and a method of manufacturing the same are not limited thereto, and the technical idea of the present invention. It is apparent that modifications and improvements are possible by those skilled in the art.

As described above, the nano-granular filter according to the present invention is not only a relatively simple manufacturing method by using a conventional AAO, but also the gap between the nickel filling layer and the size of the filling layer itself through an etching process in manufacturing AAO. By controlling freely, there is an advantage that the particles having anisotropic structure and the particles having the isotropic structure can be selectively filtered as necessary.

In addition, by controlling the size of the nano-pore during AAO fabrication can be easily changed to the filter size as desired, there is an advantage that can be separated and recovered by filtering particles having a desired shape and a predetermined particle size range as needed.

All modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

Claims (6)

(a) Anodic Aluminum Oxide (AAO) in which anodized film having a plurality of nano-sized pores is formed on the aluminum substrate by performing electro-polishing, anodizing, and etching processes on the aluminum substrate. ) Providing a template; (b) performing nickel plating on the top of the AAO template to fill nickel in the plurality of pores and simultaneously form a nickel layer on the top of the AAO template; And (c) depositing the AAO template in an anodized etching solution to remove the anodized film on the aluminum substrate; Method for producing a nano-granular filter using anodized aluminum oxide template comprising a. The method of claim 1, wherein the anodized film etching solution is prepared from the group consisting of phosphoric acid solution, sulfuric acid solution, chromic acid solution, aquatic solution and a mixture solution thereof, the nano-particle filter using an anodized aluminum template Way. Prepared according to the method of claim 1, Top nickel layer; Bottom aluminum substrate; And A plurality of pillar-shaped nickel filling layers orthogonal to the nickel layer and spaced at a predetermined interval therebetween; Nano granular filter, characterized in that having a. (a) electrolytic polishing, anodizing and etching an aluminum substrate to provide a conventional AAO template having an anodized film having a plurality of nanosized pores formed on the aluminum substrate; (b) performing nickel plating on the top of the AAO template to fill nickel in the plurality of pores and simultaneously form a nickel layer on the top of the AAO template; (c) depositing the AAO template in an anodized etching solution to remove the anodized film on the aluminum substrate; And (d) stacking and fixing the at least one pair of structures obtained in step (c) such that each nickel filling layer is disposed to cross each other; Method for producing a nano-granular filter using anodized aluminum oxide template comprising a. The method of claim 4, wherein the anodized film etching solution is prepared from the group consisting of phosphoric acid solution, sulfuric acid solution, chromic acid solution, aquatic solution, and a mixed solution thereof. Way. Prepared according to the method of claim 4 or 5, Top nickel layer; Bottom aluminum substrate; And A plurality of pillar-shaped nickel filling layers orthogonal to the nickel layer and spaced at a predetermined interval therebetween; At least a pair of structures having a nano-particle filter, characterized in that each of the nickel filling layer is stacked so as to cross each other.

Images