KR102502819B1 - Graphene fiber temperature sensor and preparing method of the same - Google Patents

Abstract

a first fiber section; and a second fiber portion connected to the first fiber portion, wherein the first fiber portion and the second fiber portion include graphene, and the first fiber portion and the second fiber portion have different degrees of reduction. Phosphorus, graphene fiber temperature sensor.

Description

Graphene fiber temperature sensor and manufacturing method thereof {GRAPHENE FIBER TEMPERATURE SENSOR AND PREPARING METHOD OF THE SAME}

The present application relates to a graphene fiber temperature sensor and a manufacturing method thereof.

A wearable temperature sensor is used to measure a person's body temperature or the temperature of a surrounding environment. In general, research is being conducted in the form of a patch attached to a person's skin or clothes or in the form of a fiber that directly measures temperature using conductive fibers.

Thermistor type, which uses the property that resistance changes according to temperature, has been mainly studied for the conventional fiber-type temperature sensor. The thermistor-type temperature sensor has a simple structure, but has a disadvantage in that an external power source is required to measure the temperature and a conductive fiber having high conductivity is additionally required to transmit the measured result.

A thermocouple-type temperature sensor does not require an external power source and is advantageous in transmitting measured signals. However, a general thermocouple-type temperature sensor requires additional processing such as soldering to join two different materials, and is based on a metal base. It is difficult to construct a flexible sensor by using a material of

Therefore, it is required to develop a high-performance fiber temperature sensor that can be flexibly bent while being in the form of a fiber for use in smart clothes.

Republic of Korea Patent Publication No. 10-2019-0057812 is a patent related to an electronic textile temperature sensor and clothing using the same. The above patent provides a temperature sensor having flexibility and elasticity by using a conductive fiber, but does not mention a temperature sensor made of a thermocouple-type flexible fiber.

The present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a graphene fiber temperature sensor.

In addition, it is an object of the present invention to provide a method for manufacturing the graphene fiber temperature sensor.

Another object of the present invention is to provide a wearable device including the graphene fiber temperature sensor.

However, the technical problem to be achieved by the embodiments of the present application is not limited to the technical problems described above, and other technical problems may exist.

A first aspect of the present application as a technical means for achieving the above technical problem is a first fiber unit; and a second fiber portion connected to the first fiber portion, wherein the first fiber portion and the second fiber portion include graphene, and the first fiber portion and the second fiber portion have different degrees of reduction. A graphene fiber temperature sensor is provided.

According to one embodiment of the present application, the first fiber part and the second fiber part may have a difference in Seebeck coefficient due to a difference in reduction degree, but is not limited thereto.

According to one embodiment of the present application, electromotive force may be generated at the interface between the first fiber part and the second fiber part due to the difference in the Seebeck coefficient, but is not limited thereto.

According to one embodiment of the present application, the first fiber portion or the second fiber portion may have a Seebeck coefficient that decreases as the degree of reduction increases, but is not limited thereto.

According to one embodiment of the present application, an end of the first fiber part and an end of the second fiber part may be electrically connected, but is not limited thereto.

According to one embodiment of the present application, the graphene may include graphene oxide or reduced graphene oxide, but is not limited thereto.

According to one embodiment of the present application, the first fiber part and the second fiber part may be in the form of a thermocouple, but are not limited thereto.

In addition, the second aspect of the present application, preparing a graphene fiber; reducing the graphene fibers; It is an object of the present invention to provide a method for manufacturing a graphene fiber temperature sensor comprising a.

According to one embodiment of the present application, the step of electrically connecting both ends of the graphene fiber may be further included, but is not limited thereto.

According to one embodiment of the present application, the step of preparing the graphene fibers may include preparing them by performing wet spinning, but is not limited thereto.

According to one embodiment of the present application, reducing the graphene fibers may include reducing all of the graphene fibers and additionally reducing some of the graphene fibers, but is not limited thereto.

According to one embodiment of the present application, the additional reduction of a portion of the graphene fibers may be using a reducing agent at a concentration different from that used to reduce all of the graphene fibers, but is not limited thereto. .

According to one embodiment of the present application, the reducing agent may include one selected from the group consisting of hydroiodic acid, hydrazine, ascorbic acid, sodium borohydride, sulfuric acid, potassium hydroxide, and combinations thereof, but is not limited thereto. .

According to one embodiment of the present application, by further reducing a portion of the graphene fiber, one graphene fiber may be divided into a first fiber portion and a second fiber portion having different Seebeck coefficients, but is limited thereto It is not.

In addition, a third aspect of the present disclosure aims to provide a wearable device including the graphene fiber temperature sensor according to the first aspect of the present disclosure.

The above-described problem solving means are merely exemplary and should not be construed as intended to limit the present disclosure. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and detailed description of the invention.

Unlike a thermistor temperature sensor that requires an external power supply for temperature measurement or a conventional thermocouple-type temperature sensor that has difficulty in configuring a flexible sensor using a metal-based material, the graphene fiber temperature sensor according to the present invention uses a flexible fiber. It is a thermocouple type temperature sensor used. Accordingly, an external power source is not required, which is advantageous in transmitting a measured signal, and a flexible temperature sensor can be configured.

In addition, the graphene fiber temperature sensor according to the present invention reduces all of the single graphene fiber and reduces the reduced A temperature sensor can be manufactured without additional processes such as soldering by implementing an integrated thermocouple type temperature sensor in which two parts with different degrees of reduction exist in a single graphene fiber through a method of further reducing a part of the graphene fiber. there is.

In addition, since the graphene fiber temperature sensor according to the present invention is a material having conductivity by itself, a separate wire for transmitting a signal of the temperature sensor is not required.

In addition, since the graphene fiber temperature sensor according to the present disclosure is flexible, it may be woven by itself or used in combination with other fiber structures.

In addition, the graphene fiber temperature sensor according to the present disclosure may be connected to a wearable device and used to measure the temperature of the body or the surrounding environment.

However, the effects obtainable herein are not limited to the effects described above, and other effects may exist.

(A) of FIG. 1 is an image of a graphene fiber temperature sensor according to an embodiment of the present invention, and (B) is an image of a graphene fiber temperature sensor according to an embodiment of the present invention connected to another fiber structure.
2 (A) is a graph showing the resistance of graphene fibers reduced in hydroiodic acid solutions of different concentrations according to an experimental example of the present application, and (B) is graphene reduced in hydroiodic acid solutions of different concentrations. It is a graph showing the Seebeck coefficient of a fiber.
3 is a graph measuring electromotive force according to temperature of a graphene fiber reduced with a reducing agent of 0.97 wt% and 30.6 wt% according to an experimental example of the present application and an integral graphene fiber temperature sensor manufactured according to an example of the present application. am.
4 is a graph measuring the magnitude of electromotive force generated by applying temperature to a graphene fiber temperature sensor according to an experimental example of the present application.
5 is a graph measuring a change in electromotive force generated when a finger contacts an interface having a different degree of reduction in a graphene fiber temperature sensor according to an experimental example of the present disclosure.

Hereinafter, embodiments of the present application will be described in detail so that those skilled in the art can easily practice with reference to the accompanying drawings. However, the present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. And in order to clearly describe the present application in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout this specification, when a part is said to be "connected" to another part, this includes not only the case of being "directly connected" but also the case of being "electrically connected" with another element in between. do.

Throughout the present specification, when a member is referred to as being “on,” “above,” “on top of,” “below,” “below,” or “below” another member, this means that a member is located in relation to another member. This includes not only the case of contact but also the case of another member between the two members.

Throughout the present specification, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

As used herein, the terms "about," "substantially," and the like are used at or approximating that number when manufacturing and material tolerances inherent in the stated meaning are given, and are intended to assist in the understanding of this disclosure. Accurate or absolute figures are used to prevent undue exploitation by unscrupulous infringers of the stated disclosure. In addition, throughout the present specification, “steps of” or “steps of” do not mean “steps for”.

Throughout the present specification, the term "combination thereof" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It means including one or more selected from the group consisting of.

Throughout this specification, reference to "A and/or B" means "A, B, or A and B".

Hereinafter, a graphene fiber temperature sensor, a manufacturing method of the graphene fiber temperature sensor, and a wearable device including the graphene fiber temperature sensor of the present application will be described in detail with reference to embodiments, examples, and drawings. However, the present application is not limited to these embodiments and examples and drawings.

A first aspect of the present application as a technical means for achieving the above technical problem is a first fiber unit; and a second fiber portion connected to the first fiber portion, wherein the first fiber portion and the second fiber portion include graphene, and the first fiber portion and the second fiber portion have different degrees of reduction. A graphene fiber temperature sensor is provided.

Conventional thermocouple-type temperature sensors are manufactured by bonding two different materials, so additional processing such as soldering is required. However, since the graphene fiber temperature sensor according to the present invention is a temperature sensor composed of a first fiber part and a second fiber part having different degrees of reduction in a single graphene fiber, a thermocouple type temperature sensor can be manufactured without an additional bonding process. there is.

According to one embodiment of the present application, the first fiber part and the second fiber part may have a difference in Seebeck coefficient due to a difference in reduction degree, but is not limited thereto.

The Seebeck effect refers to a phenomenon in which thermoelectromotive force is generated in a circuit when two different types of metals or semiconductors are joined together and a temperature difference is applied to the junction. The higher the Seebeck coefficient, the higher the electromotive force. It can be.

According to one embodiment of the present application, the first fiber portion or the second fiber portion may have a Seebeck coefficient that decreases as the degree of reduction increases, but is not limited thereto.

Using the fact that the Seebeck coefficient decreases as the degree of reduction increases, the first fiber part and the second fiber part may have different degrees of reduction, so that a difference in Seebeck coefficient between the first fiber part and the second fiber part may occur. , but is not limited thereto.

According to one embodiment of the present application, electromotive force may be generated at the interface between the first fiber part and the second fiber part due to the difference in the Seebeck coefficient, but is not limited thereto.

According to one embodiment of the present application, the first fiber part and the second fiber part may be in the form of a thermocouple, but are not limited thereto.

By using the Seebeck effect, the temperature on one side is maintained at a constant temperature and the temperature at the other end can be known by measuring the value of the thermal electromotive force. At this time, the two types of metal conductors being joined are called thermocouples.

In the graphene fiber temperature sensor according to the present disclosure, the first fiber part and the second fiber part have different degrees of reduction, and accordingly, the first fiber part and the second fiber part may have different Seebeck coefficients. no.

Since the Seebeck coefficients of the first fiber part and the second fiber part are different, the function of the temperature sensor can be performed by measuring the magnitude of the electromotive force generated when temperature is applied at the interface between the first fiber part and the second fiber part. It is not limited thereto.

According to one embodiment of the present application, an end of the first fiber part and an end of the second fiber part may be electrically connected, but is not limited thereto.

The temperature applied to the contact point of the first fiber part and the second fiber part may be measured by electrically connecting ends of the first fiber part and the second fiber part, but the present invention is not limited thereto.

For example, a measuring instrument is connected to the ends of the first fiber part and the second fiber part, and the electromotive force generated at both ends is measured to measure the temperature applied to the contact point of the first fiber part and the second fiber part. However, it is not limited thereto.

According to one embodiment of the present application, the graphene may include graphene oxide or reduced graphene oxide, but is not limited thereto.

Graphene produced by chemical vapor deposition has the advantage of being higher in purity than other graphenes and capable of producing graphene of a desired size, but has a disadvantage in that the amount of graphene produced is very small. On the other hand, reduced graphene produced by reducing graphene oxide produced by acid treatment of graphite has the advantage of being able to be produced in large quantities, but has a disadvantage in that it is difficult to realize the characteristics of pure graphene.

The graphene used herein may be a graphene fiber temperature sensor made of reduced graphene oxide obtained by reducing graphene oxide, rather than high-purity graphene produced by chemical vapor deposition (CVD). It is not limited thereto.

In addition, the second aspect of the present application, preparing a graphene fiber; reducing the graphene fibers; It is an object of the present invention to provide a method for manufacturing a graphene fiber temperature sensor comprising a.

With respect to the manufacturing method of the graphene fiber temperature sensor according to the second aspect of the present disclosure, detailed descriptions of portions overlapping with those of the first aspect of the present disclosure have been omitted. The same can be applied to the second aspect of the present application.

According to one embodiment of the present application, the step of preparing the graphene fibers may include preparing them by performing wet spinning, but is not limited thereto.

For example, a graphene oxide fiber may be prepared through wet spinning using a graphene oxide liquid crystal, but is not limited thereto.

According to one embodiment of the present application, reducing the graphene fibers may include reducing all of the graphene fibers and additionally reducing some of the graphene fibers, but is not limited thereto.

According to one embodiment of the present application, the additional reduction of a portion of the graphene fibers may be using a reducing agent at a concentration different from that used to reduce all of the graphene fibers, but is not limited thereto. .

Since the manufacturing method of a graphene fiber temperature sensor according to the present invention reduces all of a single graphene fiber and further reduces a part of the reduced graphene fiber using a reducing agent having a different concentration, the manufacturing method of a conventional temperature sensor Unlike, an additional process such as bonding may not be required, but is not limited thereto.

In addition, in addition to reducing the graphene fibers using a reducing agent, the graphene fibers may be reduced using a thermal or optical method, but is not limited thereto.

According to one embodiment of the present application, by further reducing a portion of the graphene fiber, one graphene fiber may be divided into a first fiber portion and a second fiber portion having different Seebeck coefficients, but is limited thereto It is not.

Due to the difference in reduction degree between the first fiber part and the second fiber part, the Seebeck coefficients of the first fiber part and the second fiber part may be different, but the present invention is not limited thereto.

Since the Seebeck coefficients of the first fiber part and the second fiber part are different, electromotive force is generated. Accordingly, the graphene fiber temperature sensor according to the present disclosure may measure temperature by measuring electromotive force at the ends of the first fiber part and the second fiber part in the form of a thermocouple, but is not limited thereto.

According to one embodiment of the present application, the reducing agent may include one selected from the group consisting of hydroiodic acid, hydrazine, ascorbic acid, sodium borohydride, sulfuric acid, potassium hydroxide, and combinations thereof, but is not limited thereto. .

According to one embodiment of the present application, the step of electrically connecting both ends of the graphene fiber may be further included, but is not limited thereto.

Electromotive force may be measured by electrically connecting both ends of the first fiber part and the second fiber part in order to measure the temperature applied to the junction of the first fiber part and the second fiber part, but is not limited thereto .

For example, the first fiber part and the second fiber part may be electrically connected by connecting a measuring instrument to both ends, but is not limited thereto.

In addition, a third aspect of the present disclosure aims to provide a wearable device including the graphene fiber temperature sensor according to the first aspect of the present disclosure.

With respect to the wearable device according to the third aspect of the present application, detailed descriptions of parts overlapping with the first and/or second aspects of the present application are omitted, but even if the description is omitted, the first aspect and/or the second aspect of the present application The content described in the second aspect can be equally applied to the third aspect of the present application.

The present invention will be described in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[Example 1]

In order to manufacture a graphene fiber temperature sensor, first, a graphene oxide fiber was prepared through wet spinning using a graphene oxide liquid crystal.

Subsequently, the entire prepared graphene oxide fiber was reduced with a 0.97 wt% hydroiodic acid solution, and only a portion of the reduced graphene oxide fiber was further reduced using a 30.6 wt% hydroiodic acid solution to form one graphene fiber. fabricated a graphene fiber temperature sensor with two parts with different degrees of reduction.

For convenience of explanation, the portion reduced only with 0.97 wt% hydroiodic acid solution is referred to as a first fiber portion, and the portion further reduced with a 30.6 wt% hydroiodic acid solution is referred to as a second fiber portion.

However, the first fiber part and the second fiber part are arbitrarily referred to for convenience of explanation, and the reduction degree of the first fiber part may be higher than the reduction degree of the second fiber part, and the reduction of the first fiber part degree may be lower than the degree of reduction of the second fiber portion.

Since the degree of reduction of the first fiber part and the second fiber part are different, the Seebeck coefficient is also changed. temperature can be measured.

(A) of FIG. 1 is an image of a graphene fiber temperature sensor according to an embodiment of the present invention, and (B) is an image of a graphene fiber temperature sensor according to an embodiment of the present invention connected to another fiber structure.

Referring to (A) of FIG. 1, the graphene fiber is divided into a first fiber part and a second fiber part based on the center of the graphene fiber, and the first fiber part and the second fiber part are integral and cannot be distinguished with the naked eye. You can see that it is flexible enough to build.

In addition, referring to (B) of FIG. 1 , it can be confirmed that the graphene fiber temperature sensor according to the present disclosure is flexible and can be applied to a wearable device by being coupled to other fabric tissues.

[Experimental Example 1]

2 (A) is a graph showing the resistance of graphene fibers reduced in hydroiodic acid solutions of different concentrations according to an experimental example of the present application, and (B) is graphene reduced in hydroiodic acid solutions of different concentrations. It is a graph showing the Seebeck coefficient of a fiber.

Referring to (A) of FIG. 2 , it can be seen that the reduced graphene oxide fiber in a very low concentration iodine hydrochloric acid solution (0.97 wt%) also has electrical conductivity. Therefore, it can be confirmed that the measured signal can be transmitted without connecting a separate wire.

In addition, referring to (B) of FIG. 2 , it can be confirmed that the Seebeck coefficient decreases as the reduction degree of the graphene fiber increases. Through this, by manufacturing a single graphene fiber so that two portions having different degrees of reduction exist, the temperature can be sensed by measuring the electromotive force generated according to the temperature applied to the portion having different degrees of reduction.

[Experimental Example 2]

3 is a graph measuring electromotive force according to temperature of a graphene fiber reduced with a reducing agent of 0.97 wt% and 30.6 wt% according to an experimental example of the present application and an integrated graphene fiber manufactured according to an example of the present application.

Referring to Figure 3, (A) is a graph measuring the electromotive force generated when the graphene fiber reduced with a 0.97 wt% hydroiodic acid solution is connected to copper, and (B) is a graph measuring the electromotive force generated with a 30.6 wt% hydroiodic acid solution. This graph measures the electromotive force generated when the reduced graphene fiber is connected to copper.

Referring to FIG. 3 , it can be seen that the electromotive force generated in the integrated graphene fiber according to the present application coincides with the difference in electromotive force generated when (A) and (B) are connected to copper.

Through this, it was confirmed that a thermocouple-type temperature sensor can be manufactured without a separate bonding process such as soldering.

[Experimental Example 3]

4 is a graph measuring the magnitude of electromotive force generated by applying temperature to a graphene fiber temperature sensor according to an experimental example of the present application.

Referring to FIG. 4, the change in electromotive force generated according to the temperature applied to the contact points of the first fiber part and the second fiber part having different degrees of reduction was clearly confirmed, and the correlation coefficient between the temperature difference and the electromotive force was 0.999, which is very showed high linearity. Through this, it was confirmed that the integrated graphene fiber according to the present disclosure can be used as a temperature sensor.

[Experimental Example 4]

5 is a graph measuring a change in electromotive force generated when a finger contacts an interface having a different degree of reduction in a graphene fiber temperature sensor according to an experimental example of the present disclosure.

Referring to FIG. 5 , it can be seen that the electromotive force is clearly distinguished between when the finger is in contact and when the finger is not in contact.

In addition, it was confirmed that the time constant of the sensor during the five measurements had a very fast response speed of 0.4 seconds.

The above description of the present application is for illustrative purposes, and those skilled in the art will understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present application is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts thereof should be construed as being included in the scope of the present application.

Claims (15)

a first fiber section; and
a second fiber part connected to the first fiber part;
Including,
The first fiber part and the second fiber part exist on one fiber,
The first fiber part and the second fiber part include graphene,
The first fiber portion and the second fiber portion have different degrees of reduction,
The first fiber part and the second fiber part have a difference in Seebeck coefficient due to a difference in reduction degree,
Electromotive force is generated at the interface of the first fiber part and the second fiber part due to the difference in the Seebeck coefficient,
Graphene fiber temperature sensor.
delete delete According to claim 1,
The first fiber portion or the second fiber portion has a Seebeck coefficient decreasing as the degree of reduction increases,
Graphene fiber temperature sensor.
According to claim 1,
Wherein the end of the first fiber part and the end of the second fiber part are electrically connected,
Graphene fiber temperature sensor.
According to claim 1,
The graphene includes graphene oxide or reduced graphene oxide,
Graphene fiber temperature sensor.
According to claim 1,
The first fiber part and the second fiber part are in the form of a thermocouple,
Graphene fiber temperature sensor.
preparing a graphene fiber;
reducing the graphene fibers;
including,
In the manufacturing method of the graphene fiber temperature sensor according to claim 1,
Reducing the graphene fibers,
reducing all of the graphene fibers and further reducing some of the graphene fibers;
By further reducing a portion of the graphene fiber, one graphene fiber is divided into a first fiber portion and a second fiber portion having different Seebeck coefficients,
Manufacturing method of the graphene fiber temperature sensor according to claim 1
According to claim 8,
Further comprising the step of electrically connecting both ends of the graphene fiber,
A method of manufacturing a graphene fiber temperature sensor according to claim 1 .
According to claim 8,
The step of preparing the graphene fiber,
Which comprises producing by performing wet spinning,
A method of manufacturing a graphene fiber temperature sensor according to claim 1 .
delete According to claim 8,
Further reducing a portion of the graphene fibers is to use a reducing agent at a concentration different from that used to reduce all of the graphene fibers.
A method of manufacturing a graphene fiber temperature sensor according to claim 1 .
According to claim 12,
The reducing agent comprises hydroiodic acid, hydrazine, ascorbic acid, sodium borohydride, sulfuric acid, potassium hydroxide and combinations thereof selected from the group consisting of,
A method of manufacturing a graphene fiber temperature sensor according to claim 1 .
delete A wearable device comprising the graphene fiber temperature sensor according to any one of claims 1 and 4 to 7.

Images