KR102377307B1 - Fiber-type temperature sensor with compressed micro-wrinkels and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a fibrous temperature sensor having compressed fine wrinkles and a manufacturing method for manufacturing the same. The manufacturing method comprises: a first step of coating the stretchable fibers with an elastic polymer solution in a stretched state and relaxing the compressed fine wrinkle layer on the stretchable fibers; and, after the first step, a second step of coating the temperature-sensitive layer by stretching the elastic fiber so that the fine wrinkles are flattened, and then coating the temperature-sensitive layer and relaxing it to coat the compressed temperature-sensitive layer.

Description

Fiber-type temperature sensor with compressed micro-wrinkles and manufacturing method for manufacturing the same

The present invention relates to a fibrous temperature sensor having compressed fine wrinkles and a manufacturing method for manufacturing the same.

In recent years, fiber-type sensors are in high demand due to their characteristics, such as being included in smart clothing, smart gloves, skin/organ-attachment devices, and fibers of artificial organs, enabling human health management and clinical information collection. Since the fiber-type sensor has the advantages of high air permeability, light weight, and easy deformation, weaving an electronic fiber using it can provide various biological signals (eg, pulse, respiration, electrocardiogram, and temperature). However, since stresses occurring during a wide range of motions in daily life can significantly affect the electrical properties of fibrous sensors, they are highly insensitive to interference induced by deformation (e.g., tensile or compressive deformation). There is a growing need to develop deformable and stretchable fiber-type sensors.

To date, in order to develop a fibrous sensor for stable monitoring of such bio-signals, in particular, highly deformable and stretchable that can be conformally adhered to human skin and avoid mechanical and electrical interference. Many efforts have been made to develop fibrous sensors, and strategies such as incorporating specific fractal designs, such as coil shapes, snake patterns, or pixel-like arrangements, into fibrous sensors are now being implemented.

Specifically, looking at the prior art of fabricating a fiber-type temperature sensor with reduced physical stimulation, a research team at Renmin University of China, Yapei Wang, manufactured a coil-type temperature sensor by winding up a fiber on a support. However, there is a problem in that it is difficult to apply it to fabric production due to the thick thickness of the structure in which the fiber is wound on the support, and it is difficult to secure stability with the fiber itself. Second, the Sungkyunkwan University, Nae-Eung Lee research team reduced the responsiveness to physical stimuli by slanting the fabric with a temperature fiber made of a serpentine structure. Electrical stability and temperature sensitive response were secured for the fabricated sensor, but similarly, when a tensile force was applied directly to the fiber, it showed a rapid change in resistance.

Therefore, unlike the conventional fiber-type temperature sensor as described above, the development of a fiber-type temperature sensor having inherently superior elasticity and strain-insensitivity characteristics still remains to be solved.

An object of the present invention is to provide a fiber-type temperature sensor having strain-insensitivity to physical stimuli, which leads to poor temperature sensing due to interference of electrical signals, and a method for manufacturing the fiber-type temperature sensor.

The present invention, elastic fibers; a compressed micro-wrinkle layer coated on the elastic fiber; and a compressed temperature-sensitive layer coated over the entire surface of the compressed micro-wrinkle layer.

In the present invention, the compressed fine wrinkle layer is a layer composed of periodic fine wrinkles formed on the fiber surface, for example, in a state in which the elastic fiber is stretched, a coating layer coated on the elastic fiber is compressed through the relaxation of the elastic fiber to naturally means a layer of dense wavy structure.

The wrinkle of the compressed fine wrinkle layer is characterized in that it is a wrinkle perpendicular to the longitudinal direction of the elastic fiber. This is naturally formed through the preparation of the compressed fine wrinkle layer as described above, and when the elastic fiber is stretched in the longitudinal direction and then relaxed, the compressed wrinkle perpendicular to the longitudinal direction is formed.

In addition, only when the fine wrinkle layer is compressed perpendicularly to the longitudinal direction of the stretchable fiber, the effect of preventing the breakage of the fiber-type temperature sensor according to the longitudinal extension of the stretchable fiber, an object of the present invention, may appear.

The fiber-type temperature sensor is stretch-deformed and the temperature-sensitive fine wrinkle structure on the stretchable fiber is reversibly unfolded, whereby the compressive strain energy of the fiber surface cancels the tensile stress of the fiber due to the deformation. Thus, due to the residual compressive stress on the fiber surface, such unfolding behavior prevents changes in the electrical resistance and mechanical properties of the fiber-like temperature sensor, which the deformation of the stretchable fiber may cause.

The spacing of the wrinkles is characterized in that 10 to 500㎛.

The surface of the compressed fine wrinkle layer is characterized in that the hydrophilic treatment. When the surface of the compressed fine wrinkles layer is hydrophilic, by the hydrophilic property of the conductive polymer layer, which is one of the components of the compressed temperature-sensitive layer, specifically PEDOT:PSS of the present invention, the compressed fine wrinkles layer and the compressed The temperature-sensitive layer has the effect of bonding well to each other. This hydrophilic treatment is effected via oxygen plasma, which will be described in more detail below.

The compressed fine wrinkle layer is characterized in that it is made of an insulating elastic polymer.

Since the insulating elastic polymer does not conduct electricity, a measurement value of the electrical resistance of the conductive polymer layer may be more accurate. This improves the temperature measurement accuracy of the fiber-type temperature sensor of the present invention.

The insulating elastic polymer is specifically characterized in that it consists of polyurethane.

The insulating elastic polymer is used to minimize the difference in modulus and the tensile-strain energy between the elastic fiber and the compressed temperature-sensitive layer.

The compressed temperature-sensitive layer has a property of changing electrical resistance according to a change in temperature, and includes a function of sensing the temperature around the fiber-type temperature sensor.

The compressed temperature-sensitive layer, like the formation of the compressed fine wrinkle layer, is characterized in that the compressed fine wrinkle layer is coated thereon in an unfolded state and then contracted again.

The compressed temperature-sensitive layer is characterized in that it comprises a conductive polymer layer and carbon particles dispersed on the conductive polymer layer.

The conductive polymer is poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS.

The conductive polymer and the carbon particles may be further dispersed in the temperature-sensitive solution.

The carbon particles include graphene or carbon nanotubes, specifically, single-walled carbon nanotubes (SWCNTs).

The fiber-type temperature sensor is characterized in that it further comprises a water-resistant protective layer coated on the temperature-sensitive layer.

The water-resistant protective layer is further laminated and coated on the temperature-sensitive layer, and serves to protect the fiber-type temperature sensor from damage caused by external humidity and stimulation.

The water-resistant protective layer may be, specifically, Ecoflex elastic polymer.

The present invention relates to a first step of coating a compressed fine wrinkle layer on a stretchable fiber by coating it with an elastic polymer solution in a stretched state and releasing it; And after the first step, the second step of coating the temperature-sensitive layer by coating the temperature-sensitive layer after stretching the stretchable fiber so that the fine wrinkles are flattened and then relaxing the compressed temperature-sensitive layer, manufacturing a fiber-type temperature sensor provide a way

The elastic polymer solution is characterized in that it is a solution capable of dissolving the elastic fibers. In the method for manufacturing the fiber-type temperature sensor, the elastic polymer solution dissolves the surface of the stretchable fiber, so that the bond between the stretchable fiber and the elastic polymer layer is integrally solidified to form a strong bond. characterized.

In the first step, the coating is characterized in that the dip coating of the elastic fiber to the elastic polymer solution. The dip coating is a coating process in which an object is immersed in a solution and taken out, and is one of the coating methods for applying a solution to the surface of the object.

The coating of the temperature-sensitive layer is characterized in that the coating with the temperature-sensitive polymer solution.

The temperature-sensitive polymer solution is basically a solution of a conductive polymer, and it is characterized in that carbon particles are further dispersed in the solution.

The temperature-sensitive polymer solution, specifically, is characterized in that it contains water, PEDOT:PSS and carbon particles.

After the first step and before the second step, it characterized in that it further comprises a hydrophilic treatment of the surface after stretching the elastic fiber so that the fine wrinkles are flattened, wherein the elastic fiber is selected to be less than 300% - to elongate

The hydrophilic treatment is characterized in that the oxygen plasma treatment.

The oxygen plasma treatment is one of plasma modification methods for modifying the surface of a material, and has an effect of improving adhesion by adsorbing oxygen particles to the surface of the material to modify the surface to be hydrophilic.

By the oxygen plasma treatment, in the present invention, specifically, the effect of improving the adhesion between the elastic polymer layer coated on the elastic fiber and the temperature-sensitive layer is exhibited.

The fiber-type temperature sensor of the present invention can provide a fiber-type temperature sensor having mechanical strain-insensitivity due to compressed fine wrinkles and a method for manufacturing the fiber-type temperature sensor.

In addition, the present invention can be applied to a next-generation miniaturized wearable device that can measure various biosignals even under various body movements in daily life by applying the fiber-type temperature sensor having mechanical deformation-insensitivity.

In addition, the present invention provides a stable fiber-type temperature sensor with constant electrical properties due to excellent deformation-insensitivity to various movement deformations occurring in daily life, specifically stretching and wrinkling deformation, and excellent durability against repeated use and washing. can provide

1 shows a schematic diagram of a method for manufacturing a fibrous temperature sensor with the compressed fine wrinkles.
Figure 2a shows a schematic diagram of the elastomeric polymer solution and the temperature sensitive solution.
Figure 2b shows a schematic diagram and electron microscopy image of the temperature sensitive solution.
Figure 3a shows scanning electron microscope images of the fiber-type temperature sensor of the present invention at 100um, 5um, and 200nm.
Fig. 3b shows a scanning electron microscope image of micro-wrinkles of the fibrous temperature sensor of the present invention prepared with line-strain of 0%, 100%, 200% and 300%.
Figure 4a shows optical microscopy and scanning electron microscopy images of a fiber-like temperature sensor surface under different applied strains of 0% and 60%.
Fig. 4b shows the results of FEM simulation analysis of the stress distribution applied to the fibrous temperature sensor surface when different applied strains of 0%, 30%, and 60% were applied.
Figure 4c shows a graph of compressive stress and tensile stress versus values inversely proportional to the distance between the microwrinkle structures under different applied strains of 0%, 30%, and 60%.
5A shows a graph of values inversely proportional to the distance between the micro-wrinkle structures for different 0%, 30%, and 60% applied strains.
Figure 5b shows a graph of the predicted value and the experimental value of the wrinkle effect ( γ _w ) for a value inversely proportional to the distance between the fine wrinkle structures.
5c shows a graph of stress versus strain according to the components of a fiber-type temperature sensor.
5D shows a graph of the resistance change value with respect to deformation according to a value inversely proportional to the distance between the fine wrinkle structures.
6A shows a graph of the resistance change value with respect to deformation according to the mass fraction of SWCNTs.
6B shows a graph of thermal sensitivity and strain insensitivity versus mass fraction of SWCNTs.
FIG. 6C shows a graph of resistance change values with respect to temperature according to the presence or absence of a protective layer.
6D shows a graph of the resistance change value with respect to deformation according to the pattern and structure of the temperature sensor.
Fig. 6e shows a graph of the resistance change value with respect to temperature, according to the deformation.
7A shows a graph of resistance change values with respect to temperature according to heating and cooling.
7B shows a graph of the resistance change value with respect to deformation according to the number of exercise.
7C shows a graph of the resistance change value with respect to the number of deformations according to the ambient temperature.
7D shows a graph of the resistance change value with respect to time according to the contact and removal of the hand.
8A shows a state in which the fiber-type temperature sensor is manufactured in an array form and an image in which the array is partially heated.
Figure 8b shows a graph of resistance measurement values versus temperature partially applied to the array type.
Fig. 9a shows a photograph of a smart glove in which the fiber-type temperature sensor is inserted, and a thermal image photograph when a bending operation is performed in a different ambient temperature environment after wearing the glove.
Fig. 9B shows a graph of the resistance measurement value versus the number of bending operations according to the change in the ambient temperature environment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

The terminology used in the present application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, step, operation, component, part, or combination thereof described in the specification is present, and includes one or more other features or steps. , it should be understood that it does not preclude the possibility of the existence or addition of an operation, a component, a part, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

A method for manufacturing the fiber-type temperature sensor of the present invention was performed as follows.

Example

A process of manufacturing the fiber type temperature sensor is schematically shown in FIG. 1 , and based on this, a method for manufacturing the fiber type temperature sensor will be described in detail.

1. In order to manufacture the fiber-type temperature sensor of the present invention, first, spandex (diameter of 400 μm; Kwangrim fiber, South Korea), which is an elastic fiber as a core support, was pre-stretched to less than 300%.

2. Then, it was coated on the pre-stretched spandex using a polyurethane solution, which is an elastic polymer solution. The pre-stretched polyurethane coated spandex was again relaxed, and the polyurethane layer on the spandex formed a dense, wavy, compressed micro-wrinkle layer. Thereafter, the polyurethane-coated spandex was subjected to oxygen plasma treatment for 1 minute to modify the polyurethane surface to be hydrophilic.

3. Subsequently, the polyurethane coated spandex was stretched once again, and a temperature sensitive solution, specifically, a temperature sensitive solution of PEDOT:PSS and SWCNTs, was coated on the stretched polyurethane coated spandex. In order to coat the temperature-sensitive solution, an easy coating method, dipping, was used, and the dipping process was performed by immersing the polyurethane-coated spandex in the temperature-sensitive solution and removing it. It was again relaxed to form fibers with a compressed micro-wrinkle layer consisting of spandex/polyurethane/PEDOT:PSS and SWCNTs.

4. Finally, a protective layer, specifically, Ecoflex (~50 μm thickness, Ecoflex 0030; Smooth-on, Inc., USA) elastic polymer is coated on the fiber coated with the temperature-sensitive powder, and the fiber of the present invention The type temperature sensor was completed.

Figure 2a shows a schematic diagram of the elastomeric polymer solution and the temperature sensitive solution.

In order to form the fine wrinkle structure of the fiber-type temperature sensor, the elastic polymer solution shown in Fig. 2 (a) was prepared, and in particular, the elastic polymer solution was prepared using polyurethane (Polyurethane, PU). Specifically, 0.5 g of polyurethane (Sigma-Aldrich, USA) in 10 g of chloroform (DaeJung Chemicals, South Korea) was dispersed using sonication for 1 hour.

Figure 2b shows a schematic diagram and electron microscopy image of the temperature sensitive solution.

In order to induce a change in resistance to temperature in the fiber-type temperature sensor, two temperature-sensitive materials, that is, a conductive polymer and carbon particles are dispersed, and the temperature-sensitive mixed solution shown in FIG. 2 (a), that is, the A temperature sensitive solution was prepared. Specifically, PEDOT:PSS (1.3 wt% in water, Clevious PH 1000; Heraeus, Germany) as the conductive polymer and SWCNTs (Sigma-Aldrich, USA) as the carbon particles were added to demineralized water, followed by an electrode ultrasonicator (Sonics Inc., USA) was prepared by sonication at 750 W for 6 hours in an ice water bath. In an example of the present invention, the total concentration of the temperature-sensitive dispersion containing PEDOT:PSS and SWCNTs was fixed at 6 mg/mL, and the mass fraction of SWCNTs was varied in the temperature-sensitive solution (0, 2.5, 5.0, 7.5, and 10.0 wt%).

The shape of the temperature-sensitive solution thus prepared is disclosed through a schematic diagram and an electron microscope image in FIG. 2B . To observe the morphology of the temperature-sensitive solution, a field-emission scanning electron microscope (Hitachi, S-4300) was used.

evaluation example

The fiber-type temperature sensor manufactured by the present invention was analyzed as follows.

Figure 3a shows a scanning electron microscope image taken of the fiber-type temperature sensor of the present invention at 100um, 5um, and 200nm, Figure 3b is a bone prepared with 0%, 100%, 200%, and 300% line-strain. It shows a scanning electron microscope image of the micro-wrinkle of the fiber-type temperature sensor of the present invention. From the image, it can be confirmed that the fiber-type temperature sensor manufactured by applying a larger value of line-strain has a denser fine wrinkle structure.

Figure 4a shows optical microscopy and scanning electron microscopy images of a fiber-like temperature sensor surface under different applied strains of 0% and 60%. Here, through the two types of microscopic images, it is possible to visually confirm the change in the fine wrinkle structure that occurs when deformation is applied to the fiber-type temperature sensor of the present invention.

Fig. 4b shows the results of FEM simulation analysis of the stress distribution applied to the fibrous temperature sensor surface when different applied strains of 0%, 30%, and 60% were applied. To elucidate the reversible mechanism of the corrugated microstructure on the fibrous temperature sensor, the stress distributions in various micro-wrinkled fibers containing the heat-reactive composite and PU support were calculated using finite-element method (FEM) simulations.

FEM simulation analysis was performed using commercial software (COMSOL Multiphysics version 5.2a, license number 5084832, Altsoft, South Korea) to investigate the stress distribution on the corrugation of the fiber temperature sensor. Here, a two-dimensional model of spandex fibers coated with a heat-reactive wrinkle layer was used. The model was automatically meshed with free triangular elements, and the mesh size ranged from 0.3823 to 0.9229 μm. One edge of the fiber was fixed and the other edge was stretched along the horizontal direction. When a tensile force is applied by stretching the compressed pleats of the fiber-type temperature sensor, the compressed pleats may be stretched along the stretch-deformed elastic fibers. Thereafter, the stress according to the compressed wrinkle portion can be visually confirmed through stress simulation analysis.

In contrast to the flat layer surface, as shown in Fig. 4b, the micro-corrugated surface was compressed with the stored strain energy and experienced inconsistent stress. This is because the wrinkling of the fiber surface minimizes the total energy on the fiber surface, resulting in increased mismatch in stress between the skin layer and the soft fibers. Interestingly, the micro-wrinkle structure around the residual stress compensated for the stress generation and prevented the change in the electrical resistance of the fibrous temperature sensor under the applied tensile strain.

Figure 4c shows a graph of compressive stress and tensile stress versus values inversely proportional to the distance between the microwrinkle structures under different applied strains of 0%, 30%, and 60%;

The stress distribution is expressed as the sum of the residual stress (σ _c ) and the applied tensile stress (σ _t ) around the edge of the micro-wrinkle: σ _total =σ _c +σ _t . The external tensile stress was maximized around the edge of the micro-wrinkle. This behavior of the pleated fibers with residual stress can be reversible and prevent electrical losses (eg resistance change) of the fibrous temperature sensor of the present invention under strain or deformation. Thus, the inclusion of micro-wrinkle structures on the surface of the fibers makes it possible to achieve fiber-like temperature sensors that are inherently strain-insensitive.

0.011, 0.025, 및 0.055 μm^-1)를 사용했다. 가장 조밀하게 장착된 미세-주름의 경우에서 (300%의 선-변형에 의해 생성됨, 1/λ

0.055 μm^-1), 인장 응력은 적용된 변형(<60%) 하에서 압축 잔여 응력을 초과했다 (도4c 내 상부 구역 참조). 하지만, 다른 섬유형 온도 센서에 대해, 인장 응력은 높은 변형 (60%) 하에서 우세했고 (도4c 내 하부 구역 참조), 이는 곧 섬유형 온도 센서의 전기적인 저항의 변화로 이어진다. 따라서, 본 발명의 내재적으로 변형-감응성 섬유형 온도 센서를 위해, 300% 선-변형 (1/λ

0.055 μm^-1)으로 제조된 조밀하게 장착된 미세-주름을 이용했다. To measure the stress distribution, four different fiber-type temperature sensors: a flat-surface fiber-like temperature sensor and three different micro-corrugated fiber-like temperature sensors (1/λ

0.011, 0.025, and 0.055 μm ⁻¹ ) were used. In the case of the most densely mounted micro-wrinkles (created by 300% line-strain, 1/λ

0.055 μm ⁻¹ ), the tensile stress exceeded the compressive residual stress under the applied strain (<60%) (see upper region in Fig. 4c). However, for other fiber-type temperature sensors, the tensile stress was dominant under high strain (60%) (see lower region in Fig. 4c), which leads to a change in the electrical resistance of the fiber-type temperature sensor. Therefore, for the inherently strain-sensitive fiber-type temperature sensor of the present invention, 300% pre-strain (1/λ)

Densely mounted micro-wrinkles made of 0.055 μm ⁻¹ ) were used.

5A shows a graph of values inversely proportional to the distance between the micro-wrinkle structures for different 0%, 30%, and 60% applied strains.

10 μm)을 갖는 섬유 상의 미세-주름의 파장(λ)은 적용된 선-변형이 증가함에 따라(<300%) 현저하게 감소했다. 잔여 압축 응력은 가해진 면외 변위로 인해 저장된 변형 에너지에 의해 섬유 표면 상에 발생했다.As shown in Figure 5a above, a similar amplitude ( A

The wavelength (λ) of micro-wrinkles on fibers with 10 μm) decreased significantly (<300%) with increasing applied line-strain. Residual compressive stress was generated on the fiber surface by the stored strain energy due to the applied out-of-plane displacement.

Figure 5b shows a graph of the predicted value and the experimental value of the wrinkle effect ( γ _w ) for a value inversely proportional to the distance between the fine wrinkle structures.

Iw/I0) 유무에 따른 단위 길이 사이의 비율을 추정했다: γ _w

(2π/λ)√(0.5((λ/4)²+A²)). 선-변형(ε)을 고려하면, γw는 √π/8+2(ε-_c))로 표현될 수 있다. 여기서, ε_c은 중대한 변형을 나타내고, 이는 섬유의 물질 특성에 의해 결정된다. 상기 도5b를 통해, 본 발명의 섬유형 온도 센서의 성능에 대한 예측값과 실제 실험값이 일치하는 것을 확인할 수 있다.To calculate the predicted value of the wrinkle effect ( γ _w ) on the elastic sensor fiber, the micro-wrinkle ( γ _w ) on the elastic fiber

Iw / I0 ) estimated the ratio between unit lengths with and without: γ _w

(2π/λ)√(0.5((λ/4) ² +A ² )). Considering the line-strain (ε), γw can be expressed as √π/8+2(ε- _c )). Here, ε _c represents a significant strain, which is determined by the material properties of the fibers. 5B, it can be confirmed that the predicted value for the performance of the fiber-type temperature sensor of the present invention matches the actual experimental value.

5c shows a graph of stress versus strain according to the components of a fiber-type temperature sensor. With the aid of the micro-wrinkle structure in the fibrous temperature sensor, the fiber with micro-wrinkle structure, coated or not coated with the heat-sensitive composite agent, exhibits similar stress to the fiber without micro-wrinkle structure and indicates excellent deformability. The fibers without the micro-wrinkle structure with the heat-sensitive composite experienced higher stress than the other fibers.

5D shows a graph of the resistance change value with respect to deformation according to a value inversely proportional to the distance between the fine wrinkle structures. The results, as shown in Fig. 5d, specify the relationship between the corrugations on the fiber and the relative change in resistance (ΔR/R ₀ ) when lateral strain is applied to the fiber-like temperature sensor. To specify the resistance change, we determined the initial resistance (R ₀ ) at approximately room temperature (~ 20 °C). R ₀ did not show a significant change under the applied strain. The surface corrugation increased the length of the outer conductive sensing layer in the fiber. As a result, it is possible to eliminate the elongation of the fiber-type temperature sensor and the change in electrical resistance due to deformation.

In order to measure the electrical properties of the fiber-type temperature sensor of the present invention, specifically, the tensile strain was loaded using a custom equipment (Neo-Plus, South Korea), and 1.0 mA was used using a source meter (PXIE-1073). With a constant current of , the electrical response of the fiber-type temperature sensor of the present invention under tensile strain was measured.

6A shows a graph of the resistance change value with respect to deformation according to the mass fraction of SWCNTs. Specifically, changes in stretchability and conductivity were investigated using fiber-type temperature sensors coated with different mass fractions of SWCNTs, 0, 2.5, 5.0, 7.5, and 10.0 wt%.

6B shows a graph of thermal sensitivity and strain insensitivity versus mass fraction of SWCNTs. As shown in Fig. 6b, the conductivity of the stretchable and fibrous temperature sensor without resistance change was significantly improved with increasing the mass fraction of SWCNTs in the coating material. These results were attributed to the additional electron hopping between the interfaces of PEDOT:PSS and SWCNTs, which inhibited the ionic interaction of PEDOT and PSS. The thermal sensitivity (defined as ΔR/(R 0 ΔT), up to 0.9%/°C, ΔR/(R ₀ ΔT)) of the fiber-type temperature sensor with increasing content of SWCNTs due to the reduced ratio of PEDOT:PSS, which is highly responsive to thermal energy decreased (see black line in Fig. 6b). Moreover, the strain-insensitivity, defined as (ΔL/L ₀ )/(ΔR/R ₀ ), was saturated with 5 wt % SWCNTs in the heat-sensitive conductive paste (see blue line in FIG. 6b ).

For the experiments of the present invention, as the fibrous temperature sensor of the present invention, 5 wt% in PEDOT:PSS composite material (maximum temperature sensitivity of ∼0.9%/°C), with high strain-insensitivity up to tensile strain ∼60% Highly temperature-sensitive, micro-wrinkled fibers with SWCNTs filler were used.

6C shows a graph of the resistance change value with respect to temperature according to the presence or absence of the protective layer. After laminating a protective layer of Ecoflex on micro-wrinkled fibers (in 5 wt % SWCNTs/ PEDOT:PSS) with a conductive heat-reactive layer, the fibrous temperature sensor of the present invention is subjected to different mechanical deformations up to 1000 cycles. Against this, it exhibited stable strain-insensitivity of electrical signals. In addition, in order to analyze the additional effect of the protective layer, the effect of humidity on the fiber-type temperature sensor of the present invention was minimized. For this purpose, using a vacuum drying oven (ThermoStable SOV-30, DAIHAN Scientific, South Korea), the change in resistance to temperature was measured with the effect of minimized humidity. The fiber-type temperature sensor of the present invention enables current flow so that the high mass content of CNTs is highly dominated and unaffected by the presence of water molecules, making it more insensitive against humidity. In addition, the protective Ecoflex layer exhibits relatively waterproof, hydrophobic properties, which reduces the degradation of conductivity compared to the sensor without the protective layer.

6D shows a graph of the resistance change value with respect to deformation according to the pattern and structure of the temperature sensor.

To further improve elasticity without changing the electrical resistance, as shown in Fig. 6d, the fibrous temperature sensor of the present invention was knitted into a deformable fiber having a snake pattern. In addition to the intrinsic stretchability of the pleat-fiber-like temperature sensor, the patterned fiber-like temperature sensor embedded into the soft fabric, under the condition of being stretched with minimal change in electrical resistance (see inset image in Fig. It is possible to significantly improve the deformability (up to 180%; inherently <60% without fractal design) of fiber-type temperature sensors. Due to this capability, the fiber-type temperature sensor of the present invention exhibited the highest strain-insensitivity among the reported fiber-type temperature sensors so far.

Fig. 6e shows a graph of the resistance change value with respect to temperature, according to the deformation.

To describe the linear and reversible behavior between temperature and electrical resistance, we used a simple model described as a function of temperature in the Arrhenius-like equation.

ln(R)=ln(R _∞ )+ Ea/2kT=ln(R _∞ )+B/T (1)

Here, k denotes the Boltzmann constant, Ea denotes the activation energy, and B denotes the thermal index. R and R _∞ represent the resistance of the sensor at temperature T and infinite temperature, T _∞ , respectively. In our calculations, we obtained the thermal index (B = 955.8 K), activation energy (Ea = 166 meV), and TCR = 1.05 after plotting the linear fit results. The estimated B of the fiber-type temperature sensor of the present invention exhibits a relatively low value, indicating the ability to sensitively monitor a specific range of human skin temperature. Interestingly, the change in TCR was not significant (standard deviation of ~0.06) with increasing elongational strain of the fiber-type temperature sensor of the present invention, showing a special inherent strain-insensitivity. Owing to the presence of a densely mounted micro-wrinkle and strain-free TCR in the fiber-type temperature sensor of the present invention, the sensor exhibited excellent strain-insensitivity under tensile stress induced by lateral strain, and the sensor exhibited excellent strain-insensitivity. hinted that it could be implemented without an expensive post-signal process

7A shows a graph of resistance change values with respect to temperature according to heating and cooling. Loads from 20 to 120 °C were plotted against the applied temperature (see red line in Figure 7a). Here, ΔR/R ₀ decreased due to the negative thermal coefficient (NTC) of the sensing composite layer. The slope of ΔR/R ₀ specified the temperature sensitivity of the sensor (0.6%/°C–0.9%/°C), and the change in the relative resistance of our temperature sensor was due to the NTC behavior of the conductive composites with PEDOT:PSS and SWCNTs. decreased as the temperature increased up to 120°C. Moreover, negligible hysteresis was observed during the process of applying and removing thermal loads (see red and blue lines in Fig. 7a), indicating the excellent thermal sensitivity of the sensing layers of PEDOT:PSS and CNTs.

7B shows a graph of the resistance change value with respect to deformation according to the number of exercise. This is to test the durability of the fiber-type temperature sensor, and the fiber-type temperature sensor of the present invention showed similar resistance change values in all of the one-time deformation range, 100-time deformation range, and 1000-time deformation range.

7C shows a graph of the resistance change value with respect to the number of deformations according to the ambient temperature. In addition, it was confirmed that the on/off response when a thermal load was applied and removed (20 and 50 °C) to the fiber-type temperature sensor was highly repeatable.

7D shows a graph of the resistance change value with respect to time according to the contact and removal of the hand. In addition, the fiber temperature sensor exhibited a short response time (6 s) and recovery time (30 s) upon finger contact, and the temperature was measured to be ~32 °C.

8A shows a state in which the fiber-type temperature sensor is manufactured in an array form and an image in which the array is partially heated. In order to measure the temperature-dependent resistance measurement value of the fiber-type temperature sensor of the present invention, an electronic fiber including the fiber-type temperature sensor was knitted in the form of an array of 9 cm Х 9 cm, 3 Х 3 arrays. Multiple detections in response to human finger skin temperature depending on the location of the array were performed by placing a portion of the array in cold contact and in another portion body temperature (a careful contact of ˜10 kPa). The low temperature cooled the skin of one human finger through contact with a vial containing ice water. After application of the temperature, thermal imaging (IR) images of the electronic fiber for different temperatures were obtained using an IR C3 camera (FLIR system, USA), which is shown in Fig. 8a.

Figure 8b shows a graph of resistance measurement values versus temperature partially applied to the array type. The resistance according to the partially applied temperature of the array form was measured, and the change in the electrical resistance of the electronic fiber caused by the different temperatures is shown through the graph of FIG. 8B . The graph corresponded precisely to the thermal imaging image of the electronic fiber taken through a thermal imaging camera.

As shown in the thermal image image and the graph showing the change in electrical resistance, the electronic fiber shows an excellent change in electrical resistance according to the ambient temperature, so that the fiber-type temperature sensor of the present invention is used for measuring the ambient temperature. It has been proven that it can be used.

Fig. 9a shows a photo of a smart glove in which the fiber-type temperature sensor is inserted, and a thermal image photo when a bending operation is performed in a different ambient temperature environment after wearing the glove, and Fig. 9b is a change in ambient temperature environment Shows a graph of the resistance measurements versus the number of bending operations according to .

The fiber-type temperature sensor of the present invention is inserted into a smart glove to apply a continuous deformation (e.g., bending or unfolding) generated by a gesture, while providing for different temperatures when the glove is placed in an oven or refrigerator. The time-dependent resistance within the reaction was measured.

During repeated gripping of the gloved hand, as shown in FIG. 9A , when temperature stimulation and tensile stimulation were simultaneously applied, a thermal image of the smart glove according to the hand gripping motion and ambient temperature change was obtained. As can be seen from the thermal image, the fiber-type temperature sensor of the present invention shows a constant thermal image despite the deformation of the fiber-type temperature sensor under the same temperature condition (low temperature or high temperature). In addition, the number of gripping times of the hand wearing the smart glove, and the change in electrical resistance of the glove according to the repeated temperature change around it were recorded, and as shown in FIG. It can be confirmed that it has a stable and uniform electrical resistance value against repeated temperature changes. Therefore, by inserting the fiber-type temperature sensor of the present invention into the glove, it is possible to monitor the ambient temperature in real time, and it is possible to measure the external temperature regardless of bending the finger. This also proves that the fiber-type temperature sensor of the present invention can be used for a wide range of electronic textile applications, since it can be inserted into textile-type clothing in addition to gloves.

Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can.

Claims (22)

elastic fibers;
a compressed micro-wrinkle layer coated on the elastic fiber; and
a compressed temperature-sensitive layer coated over the entire face of the compressed micro-wrinkle layer;
A first step of coating the elastic fibers in a stretched state with an elastic polymer solution and then relaxing the compressed micro-wrinkle layer on the elastic fibers; and
Manufactured through a second step of coating the temperature-sensitive layer that is compressed by coating and relaxing the temperature-sensitive layer after stretching the elastic fiber so that the fine wrinkles are flattened after the first step,
Fiber-type temperature sensor. According to claim 1,
The wrinkle of the compressed fine wrinkle layer, characterized in that the wrinkle is perpendicular to the longitudinal direction of the elastic fiber,
Fiber-type temperature sensor. According to claim 1,
Characterized in that the spacing of the wrinkles is 10 to 500 μm,
Fiber-type temperature sensor. delete According to claim 1,
The surface of the compressed micro-wrinkle layer is characterized in that the hydrophilic treatment,
Fiber-type temperature sensor. According to claim 1,
The compressed fine wrinkle layer is characterized in that it is made of an insulating elastic polymer,
Fiber-type temperature sensor. According to claim 1,
The compressed micro-wrinkle layer is characterized in that made of polyurethane,
Fiber-type temperature sensor. delete According to claim 1,
wherein the compressed temperature-sensitive layer comprises a conductive polymer layer and carbon particles dispersed on the conductive polymer layer,
Fiber-type temperature sensor. 10. The method of claim 9,
The conductive polymer layer is characterized in that PEDOT: PSS,
Fiber-type temperature sensor. 10. The method of claim 9,
The carbon particles are characterized in that they include graphene or carbon nanotubes,
Fiber-type temperature sensor. According to claim 1,
Further comprising a water-resistant protective layer coated on the temperature-sensitive layer,
Fiber-type temperature sensor. A first step of coating the elastic fibers in a stretched state with an elastic polymer solution and then relaxing the compressed micro-wrinkle layer on the elastic fibers; and
After the first step, the second step of coating the temperature-sensitive layer by stretching the elastic fiber so that the fine wrinkles are flattened, and then coating the temperature-sensitive layer and relaxing it to coat the compressed temperature-sensitive layer,
A method of manufacturing a fiber-type temperature sensor. 14. The method of claim 13,
The elastic polymer solution is characterized in that it is a solution capable of dissolving the elastic fibers,
A method of manufacturing a fiber-type temperature sensor. 15. The method of claim 14,
characterized in that the elastic polymer solution is a solution capable of dissolving the surface of the stretchable fiber to form a bond by integrally coagulating the surface of the stretchable fiber and the elastic polymer layer,
A method of manufacturing a fiber-type temperature sensor. 15. The method of claim 14,
In the first step, the coating is characterized in that the dip coating of the elastic fiber into the elastic polymer solution,
A method of manufacturing a fiber-type temperature sensor. 15. The method of claim 14,
The coating of the temperature-sensitive layer is characterized in that the coating with a temperature-sensitive polymer solution,
A method of manufacturing a fiber-type temperature sensor. 18. The method of claim 17,
The temperature-sensitive polymer solution is characterized in that the conductive polymer solution,
A method of manufacturing a fiber-type temperature sensor. 19. The method of claim 18,
The temperature-sensitive polymer solution is characterized in that carbon particles are dispersed,
A method of manufacturing a fiber-type temperature sensor. 19. The method of claim 18,
The temperature-sensitive polymer solution is characterized in that it contains water, PEDOT: PSS and carbon particles,
A method of manufacturing a fiber-type temperature sensor. 15. The method of claim 14,
After the first step and before the second step, after stretching the elastic fiber so as to flatten the fine wrinkles, the method further comprising hydrophilic treatment of the surface,
A method of manufacturing a fiber-type temperature sensor. 22. The method of claim 21,
The hydrophilic treatment is characterized in that oxygen plasma treatment,
A method of manufacturing a fiber-type temperature sensor.

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