KR101846084B1 - Fabrication method of conductive fibers - Google Patents

Abstract

More particularly, the present invention relates to a method of fabricating a conductive metal (e.g., Pt) thin film on a predetermined fiber (e.g., cotton fiber) surface using a low temperature atomic layer deposition (ALD) Coating, it is possible to easily adjust the resistance itself according to the thickness of the coating film, to uniformly coat the conductive thin film on the fine fiber, to minimize the heterogeneity as the conductive fiber, to easily adjust the resistance, Lt; RTI ID = 0.0 > low-resistance < / RTI > conductive fibers.

Description

TECHNICAL FIELD [0001] The present invention relates to a conductive fiber,

More particularly, the present invention relates to a method of fabricating a conductive metal (e.g., Pt) thin film on a predetermined fiber (e.g., cotton fiber) surface using a low temperature atomic layer deposition (ALD) Coating, it is possible to easily adjust the resistance itself according to the thickness of the coating film, to uniformly coat the conductive thin film on the fine fiber, to minimize the heterogeneity as the conductive fiber, to easily adjust the resistance, Lt; RTI ID = 0.0 > low-resistance < / RTI > conductive fibers.

A wearable computer (or wearable computer), which was originally announced by Ivan Sutherland of MIT in the past, is a combination of a computer and clothing that allows computers to be used anywhere, anytime, anywhere. Technology. In this regard, a number of studies have been carried out in order to make it possible to wear it on the body or clothes through miniaturization and light weight, and recently, various types of wearable computers have been commercialized and utilized in various fields including military and medical fields have.

In addition, the wearable computer combined with the textile fashion field has created a new field of smart clothing, a new concept. Smart clothing is a technology that embodies wearable systems on clothing using conductive fibers that combine conductive materials with clothing fibers.

These conductive fibers are electrically conductive fibers. Conductive fibers with excellent flexibility are the core materials of computers that can be worn. As interest in computers that can be worn increases, the development of conductive fibers is actively under way.

On the other hand, low resistance (i.e., high electrical conductivity) is basically required to be applied to a computer material that can be worn with conductive fibers, and various attempts have been made to realize low resistance of conductive fibers.

However, the conductive fiber needs to have a proper resistance value according to its specific use, has high flexibility, has a low degree of heterogeneity at the time of wearing, and has a certain level of durability. In addition, conventional conductive fiber fabrication methods require high energy, such as high temperature, resulting in inefficiency in the manufacturing process, and in some cases, there is a problem that raw fiber can be damaged due to high temperature or the like.

In addition to low resistance and flexibility, a new type of conductive material, which can easily adjust the resistance itself as desired, minimizes the heterogeneity of the fibers, improves the durability through the provision of uniform conductivity, Development of fiber fabrication methods is required.

Korean Patent Publication No. 10-2012-0017436

The present invention has been made to solve the problems of the prior art as described above, and it is an object of the present invention to provide a new type of conductive fiber capable of simultaneously realizing low resistance, flexibility, ease of resistance control, minimized heterogeneity, uniformity of conductivity, durability, And a manufacturing method thereof.

In order to accomplish the above object, the present invention provides a method of coating a conductive thin film by depositing a metal on the surface of a fiber by using an atomic layer deposition (ALD) method, wherein the number of unit cycles of the atomic layer deposition process is changed Wherein the thickness of the conductive thin film is adjusted so that the resistance of the conductive fiber can be controlled.

Also, the present invention provides a method for producing a conductive fiber, wherein the fiber is a cotton fiber, hemp fiber, silk fiber, or Nomax synthetic fiber.

Further, the present invention provides a method for producing a conductive fiber, wherein the metal is platinum (Pt).

Also, the present invention provides a method for fabricating a conductive fiber, wherein the deposition of the metal is performed at a low temperature of from room temperature to 300 ° C.

Also, the conductive thin film is coated with a thickness in the range of 100 to 1000 ANGSTROM.

Also, the conductive fiber has a resistance of 2? 50? / Cm per unit length according to the thickness of the coating film.

Further, the conductive fiber is used as a material of a wearable computer (e.g., a heater or a pressure sensor).

A) disposing cotton fibers in the reaction chamber; b) feeding and adsorbing the vaporized metal precursor over the face fibers in the reaction chamber; c) supplying a purge gas to remove excess vaporized metal precursor from the reaction chamber; d) forming a conductive thin film by supplying and reacting a reaction gas onto the surface fiber on which the metal precursor is adsorbed; e) supplying a purge gas to remove excess reaction gas and reaction by-products from the reaction chamber; And f) repeating the steps b) to e) sequentially until a conductive thin film having a desired thickness is obtained.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to efficiently form a conductive thin film on raw fiber at a low temperature.

In particular, there is an advantage that the resistance value can be easily adjusted by using the change of the coating thickness through the ALD cycle adjustment as well as the low resistance (about 2 Ω per unit length) is given to the conductive fiber.

In addition, since the conductive fiber is directly applied to the surface which is currently used as a clothing material, it is possible to minimize the inherent heterogeneity of existing conductive fibers.

In addition, the excellent step coverage of the ALD process can uniformly coat the metal thin film on many fine fibers forming the fiber and can ensure excellent durability.

The conductive fiber fabricated according to the present invention is expected to be applicable to various devices and sensors of a computer that can be worn and can contribute to the development of a computer itself which can be planted in everyday clothing without any sense of difference.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic representation of a process cycle of an atomic layer deposition (ALD) process used to coat a conductive thin film on a fiber according to the present invention.
FIG. 2 is a graph showing a growth rate and a resistivity of a thin film according to the deposition temperature in the low-temperature ALD Pt process of the present invention. FIG.
3 is a SEM image of ALD Pt deposited on SiO ₂ at a deposition temperature of 80 ° C.
FIG. 4 is a graph showing a resistance change according to a coating thickness (ALD cycle number) in the low temperature ALD Pt process of the present invention.
Figure 5 is an SEM image of conductive fibers deposited with ALD Pt on cotton fibers at a deposition temperature of 80 ° C in accordance with one embodiment of the present invention.
FIG. 6 is a view showing the structure of a pressure sensor and its performance as an application example of the conductive fiber fabricated according to the present invention.
FIG. 7 shows an example of application of the conductive fiber fabricated according to the present invention, showing the structure of a heater and its performance.

Hereinafter, the present invention will be described in detail.

A method of fabricating a conductive fiber according to the present invention includes coating a conductive thin film by depositing a metal on the surface of a fiber using an atomic layer deposition (ALD) method, wherein the conductive thin film is formed by changing the number of unit cycles of the atomic layer deposition process And the resistance of the conductive fiber can be controlled by adjusting the coating thickness of the conductive thin film.

That is, the present invention uses the atomic layer deposition (ALD) method to uniformly coat a conductive metal thin film on a raw fiber to provide low resistance and adjust the ALD process condition (ALD cycle adjustment) It is a very easy-to-adjust technology.

The atomic layer deposition (ALD) is a process in which a precursor and a reactant capable of causing a chemical reaction with each other are cyclically repeated (see FIG. 1) . The reaction of the precursors is performed only on the surface of the precursor, and since the thin film is deposited on a cycle basis, excellent step coverage can be achieved, and the thickness can be controlled at the atomic level. The advantage of the thin film characteristic and suppression of impurity formation have.

In the present invention, the fiber, which is a main material for producing the conductive fiber, may be any fiber material actually used for producing clothes. For example, natural fibers such as Cotton, Hemp or Silk; And Nomax (flame retardant fiber containing Kevlar fiber) as a synthetic fiber, and cotton fibers are preferably used. That is, the present invention can produce a conductive fiber by applying yarn or cloth of a cotton material, which is a typical clothing material, to solve the inherent heterogeneity problem inherent in existing conductive fibers and to secure excellent flexibility.

In the present invention, the metal may be any metal capable of imparting conductivity to the nonconductive fiber, such as platinum (Pt), gold (Au), silver (Ag), copper (Cu) Platinum (Pt) is used. Meanwhile, the process of coating the surface of the nonconductive fiber with atomic layer deposition (ALD) using platinum (Pt) as a metal is also abbreviated as "ALD Pt process".

When the atomic layer deposition (ALD) is performed according to the present invention, the metal precursor may be a metal organic or a metal halide depending on the kind of a ligand bonded to a metal atom.

The reaction gas for forming the conductive thin film to react with the metal precursor is oxygen from the side which may be used, such as _{H 2 O, H 2 O 2} , O 2 and O _3, to minimize the formation of oxide containing a hydroxyl group (O ₂ ) Is preferably used.

The present invention is also advantageous in that the deposition of the conductive metal thin film can be performed on a fiber surface having a low temperature ranging from room temperature to 300 ° C, for example, from 80 to 300 ° C, more specifically, from 80 to 100 ° C or so. As a result, it is possible to reduce production cost and effectively prevent damages caused by heat of the fiber raw material to be deposited.

In one embodiment, according to the present invention, a conductive Pt film can be deposited at a deposition temperature of 80 캜 at a rate of 0.2 Å / cycle.

The conductive fiber may have a resistance of 2 to 50 Ω / cm per unit length (for example, 250 to 2000 times of ALD cycle) depending on the thickness of the coating film. That is, the conductive fiber fabricated according to the present invention has a resistance of at least 2 Ω per unit length and has a low resistance. In addition, since the resistance value can be easily adjusted, various types of elements and sensors of a computer .

The thickness of the conductive thin film can be variously adjusted according to the number of ALD cycles, for example, in the range of 100 to 1000 angstroms (for example, 500 to 5000 times of ALD cycles).

The conductive fibers fabricated in accordance with the present invention may be used as a conductive material in the manufacture of wearable computer materials, such as sensors or devices mounted on wearable computers (e.g., fiber-based pressure sensors and heaters) Can be widely used.

The method for producing a conductive fiber of the present invention comprises:

a) disposing cotton fibers in the reaction chamber (and heating to a predetermined temperature if necessary);

b) feeding and adsorbing the vaporized metal precursor over the face fibers in the reaction chamber;

c) supplying a purge gas to remove excess vaporized metal precursor from the reaction chamber;

d) forming a conductive thin film by supplying and reacting a reaction gas onto the surface fiber on which the metal precursor is adsorbed;

e) supplying a purge gas to remove excess reaction gas and reaction by-products from the reaction chamber; And

f) repeating the steps b) to e) sequentially until a conductive thin film having a desired thickness is obtained.

Hereinafter, the present invention will be described more specifically by way of examples. However, these examples are provided only for the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

Example 1: Preparation of silica (SiO ₂ ) ALD Pt coating on substrate

ALD Pt coating was performed on silica (SiO ₂ ) substrate by deposition temperature according to the following process:

a) A silica (SiO ₂ ) substrate was placed in the reaction chamber.

[(1,2,5,6-η) -1,5-hexadiene] dimethylplatinum (II) (HDMP) which is a vaporized Pt precursor on the surface of a silica (SiO ₂ ) ) For 3 seconds. At this time, to obtain a proper vapor pressure of the Pt precursor, a bubbler containing the precursor was heated to 50 DEG C and the flow rate of the carrier gas was maintained at 50 sccm.

c) Excess vaporized Pt precursor, except for the Pt precursor adsorbed physically or chemically on the substrate surface, was removed from the reaction chamber by supplying argon purging gas at a flow rate of 50 sccm for 3 seconds.

d) Oxygen (O ₂ ) was added as a reaction gas to the silica substrate on which the Pt precursor was adsorbed for 6 seconds and reacted with the adsorbed Pt precursor to form a conductive thin film. At this time, the flow rate of oxygen (O ₂ ) was maintained at 200 sccm.

e) Surplus reaction gas and reaction by-products were removed from the reaction chamber by supplying argon purging gas at a flow rate of 50 sccm for 3 seconds.

f) The cycle was repeated until the conductive thin film was formed to a desired thickness and Pt was coated by atomic layer deposition (ALD).

FIG. 2 shows the growth rate and resistivity of the thin film according to the deposition temperature. Even at a low deposition temperature of 80 ° C, the conductive thin film was deposited, and the growth rate of the thin film was found to be 0.2 Å / cycle.

FIG. 3 is an SEM image of ALD Pt deposited on SiO ₂ at a deposition temperature of 80 ° C. (* film growth rate: 0.2 Å / cycle, cycle: 1000 times, film thickness: 200 Å).

Example  2: Cottonseed ( Cotton thread ) For fiber ALD Pt  coating

The same as Example 1, except that ALD Pt coating was performed on cotton thread fibers for general garments instead of silica (SiO ₂ ) substrate.

FIG. 4 shows the resistance change according to the coating thickness (the number of ALD cycles). As the thickness of the coating increases, the resistance decreases and the resistance value is also very low, which is about 2? 50? / Cm.

5 is an SEM image of the conductive fiber fabricated according to Example 2. It was confirmed that Pt was uniformly coated with excellent step coverage over the whole cotton fibers (* deposition temperature: 80 캜, thin film growth rate: 0.2 Å / cycle, cycle: 1000 times, thin film thickness: 200 Å).

Example  3: ALD Pt  Pressure sensors and heaters using coated cotton fibers

A pressure sensor and heater for a wearable computer were fabricated using the conductive fiber fabricated according to Example 2 (* deposition temperature: 80 캜, film thickness: 200 Å).

FIGS. 6 and 7 illustrate the structure and performance of the pressure sensor and the heater manufactured according to Example 3, and it was confirmed that the conductive fiber according to the present invention exhibits excellent sensing performance and thermal performance.

Claims (12)

The conductive thin film is coated by depositing metal on the fiber surface using Atomic Layer Deposition (ALD)
The metal precursor used in the atomic layer deposition method is [(1,2,5,6-.eta.) - 1,5-hexadiene] dimethylplatinum (II) (HDMP)
Characterized in that the deposition of the metal is carried out at < RTI ID = 0.0 > 80-100 C. &
Method of making conductive fiber.
The method according to claim 1,
Characterized in that the fibers are cotton fibers, Hemp fibers, silk fibers or Nomax synthetic fibers.
Method of making conductive fiber.
3. The method of claim 2,
Characterized in that the fibers are cotton fibers for clothing.
Method of making conductive fiber.
The method according to claim 1,
Characterized in that the metal is platinum (Pt).
Method of making conductive fiber.
The method according to claim 1,
Wherein the resistance of the conductive fiber can be controlled by adjusting the coating thickness of the conductive thin film by changing the number of unit cycles of the atomic layer deposition process.
Method of making conductive fiber.
The method according to claim 1,
Wherein the conductive thin film is coated to a thickness ranging from 100 to 1000 ANGSTROM.
Method of making conductive fiber.
The method according to claim 1,
Wherein the conductive fiber has a resistance of 2 to 50? / Cm per unit length depending on the thickness of the coating film.
Method of making conductive fiber.
The method according to claim 1,
Characterized in that the conductive fibers are used as a material of a wearable computer.
Method of making conductive fiber.
9. The method according to any one of claims 1 to 8,
Characterized in that the conductive fibers are used as a material for elements or sensors constituting a wearable computer.
Method of making conductive fiber.
10. The method of claim 9,
Characterized in that the device is a fiber based heater.
Method of making conductive fiber.
10. The method of claim 9,
Characterized in that the sensor is a fiber based pressure sensor.
Method of making conductive fiber.
a) disposing cotton fibers in the reaction chamber;
b) feeding and adsorbing the vaporized metal precursor [(1,2,5,6-η) -1,5-hexadiene] dimethylplatinum (II) (HDMP) onto the surface fibers in the reaction chamber;
c) supplying a purge gas to remove excess vaporized metal precursor from the reaction chamber;
d) supplying a reaction gas onto the surface fiber on which the metal precursor is adsorbed and reacting at 80 to 100 캜 to form a conductive thin film;
e) supplying a purge gas to remove excess reaction gas and reaction by-products from the reaction chamber; And
f) repeating the steps b) to e) sequentially until a conductive thin film having a desired thickness is obtained.
Method of making conductive fiber.

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