A nanofiber thermal conductivity measuring device and a measuring method thereof

Abstract

The present disclosure provides a kind of nanofiber thermal conductivity measuring device, the measuring device includes: middle hollow base, first and second side wall are formed around the hollow place and oppositely arranged third and fourth side wall;Two conductive electrodes are formed on the first and second side wall respectively;And support layer, adhesive layer and suspension electrode are sequentially stacked from bottom to top, the suspension electrode is supported on the first and second side wall by support layer, current is applied to the suspension electrode by two conductive electrodes to make it as hot end, the thermal resistance of suspension electrode is greater than the thermal resistance of the nanofiber to be measured, and the two ends of nanofiber are supported on the suspension electrode and the fourth side wall respectively.The suspension electrode in the present disclosure has the characteristics of long electrode length and small current flow area, so it has much greater thermal resistance than conventional single fiber measuring device, and can solve the problem of low signal-to-noise ratio in low thermal conductivity nanofiber thermal conductivity measurement.

Description

Technical Field

[0001] This disclosure belongs to the field of nanomaterial thermal conductivity measurement technology, and specifically relates to a device and method for measuring the thermal conductivity of nanofibers. Background Technology

[0002] Low-dimensional materials refer to materials with sufficiently small spatial dimensions in one dimension, typically on the nanometer scale. Nanofibers are a typical example of low-dimensional materials. Studies have shown that as the fiber diameter decreases, the thermal conductivity of some nanofiber materials increases significantly in the axial direction of the fiber. For example, the thermal conductivity of a 9.8 nm diameter carbon nanotube exceeds 2000 W / m·K (Fujii M, Zhang X, Xie H, et al. Measuring the thermal conductivity of a single carbon nanotube[J]. Physical review letters, 2005, 95(6): 065502.), which is much higher than the thermal conductivity of carbon itself. Therefore, developing devices and methods for characterizing the thermal conductivity of nanofibers is crucial for understanding the size effect of their thermal conductivity and guiding their optimization.

[0003] Existing research has extensively characterized the thermal conductivity of low thermal resistance fibers made of materials such as carbon and metal oxides at the single-fiber scale (the bulk thermal conductivity of these materials is typically greater than 2 W / m·K). However, research on the characterization of the thermal conductivity of low thermal conductivity nanofibers, such as ionomer nanofibers used in fuel cell catalyst layers (the bulk thermal conductivity of these fibers is approximately 0.2 W / m·K), is still lacking. Currently available devices for measuring the thermal conductivity of single nanofibers are mostly designed for low thermal resistance nanofibers, resulting in low signal-to-noise ratios and poor measurement accuracy for materials with low thermal conductivity. Therefore, there is an urgent need for a testing device specifically designed for the thermal conductivity of low thermal conductivity nanofibers. Summary of the Invention

[0004] This disclosure aims to address at least one of the technical problems existing in the prior art.

[0005] Therefore, the present disclosure provides a device for measuring the thermal conductivity of nanofibers, which can accurately and effectively measure the thermal conductivity of nanofibers with low thermal conductivity.

[0006] To achieve the above objectives, the present disclosure adopts the following technical solution:

[0007] This disclosure provides a device for measuring the thermal conductivity of nanofibers, comprising:

[0008] The base has a hollowed-out center, and a first sidewall and a second sidewall, as well as a third sidewall and a fourth sidewall, are formed around the hollowed-out area.

[0009] A first conductive electrode and a second conductive electrode are respectively formed on the first sidewall and the second sidewall; and

[0010] The structure consists of a support layer, an adhesive layer, and a suspension electrode stacked sequentially from bottom to top. The suspension electrode is supported by the support layer on the first and second sidewalls. Both ends of the suspension electrode are connected to the first and second conductive electrodes, respectively. Current is applied to the suspension electrode through the first and second conductive electrodes, making the suspension electrode a hot end. The thermal resistance of the suspension electrode is greater than the thermal resistance of the nanofiber to be tested. Both ends of the nanofiber are supported on the suspension electrode and the fourth sidewall, respectively.

[0011] In some embodiments, the thermal resistance of the suspension electrode should be greater than or equal to 10% of the thermal resistance of the nanofiber.

[0012] In some embodiments, the length of the suspension electrode does not exceed 250 μm and the cross-sectional area through which the current flows does not exceed 2.5 μm. 2 .

[0013] In some embodiments, the distance between the suspension electrode and the fourth sidewall is no more than 25 μm.

[0014] In some embodiments, the coefficient of thermal expansion of the material used to make the suspension electrode does not exceed 1.8 × 10⁻⁶. -5 ℃ -1 The coefficient of thermal expansion of the material used to make the support layer does not exceed 1.8 × 10⁻⁶. -5 ℃ -1 .

[0015] In some embodiments, the adhesive layer is made of metal to ensure the bonding between the suspension electrode and the support layer.

[0016] In some embodiments, the distance from the bottom of the support layer to the bottom of the substrate should be greater than or equal to 200 μm.

[0017] In some embodiments, the substrate is made of an insulating material and the temperature of the substrate is kept consistent with the ambient temperature.

[0018] In some embodiments, the thermal conductivity of the nanofibers does not exceed 10 W·(m·K). -1 .

[0019] The measurement method provided in the second aspect of this disclosure according to any embodiment of the measuring apparatus of the first aspect of this disclosure includes:

[0020] 1) Calibrate the temperature coefficient of resistance of the suspension electrode to determine the relationship between the resistance of the suspension electrode and temperature;

[0021] 2) The thermal conductivity of the suspension electrode is calibrated according to the relationship between the resistance and temperature of the suspension electrode and the following formula:

[0022]

[0023] Where λ is the thermal conductivity of the suspension electrode, q v Where is the heating power of the suspension electrode, and L is the length of the suspension electrode. t0 is the average temperature of the suspension electrodes, and t0 is the ambient temperature. This is the average temperature rise of the suspension electrodes;

[0024] 4) Support the two ends of the nanofiber on the suspension electrode and the fourth sidewall, respectively. Based on the relationship between the average temperature rise of the suspension electrode and the heating power under different heating powers, and using a one-dimensional thermal conductivity model, the average temperature rise of the suspension electrode after placing the nanofiber should satisfy the following formula:

[0025]

[0026] Among them, W f H represents the width of the nanofiber. f Where λ is the thickness of the nanofiber, W is the width of the suspension electrode, H is the thickness of the suspension electrode, and λ is the thickness of the nanofiber. f The thermal conductivity of nanofibers;

[0027] 4) Combine formulas (1) and (2) to calculate the thermal conductivity of the nanofiber.

[0028] The present disclosure provides a device for measuring the thermal conductivity of nanofibers, which has the following characteristics and beneficial effects:

[0029] This disclosure provides a device and method for measuring the thermal conductivity of nanofibers. The suspension electrode, serving as the hot end, features a long electrode length and a small current flow area, resulting in a thermal resistance far greater than that of conventional single-fiber measuring devices. This solves the problem of low signal-to-noise ratio in measuring the thermal conductivity of low-thermal-conductivity nanofibers. Simultaneously, the support layer beneath the suspension electrode effectively increases its mechanical strength, ensuring test repeatability and device durability. Therefore, this disclosure can accurately and effectively measure the thermal conductivity of low-thermal-conductivity nanofibers. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the nanofiber thermal conductivity measuring device provided in the embodiments of this disclosure;

[0031] Figure 2In the embodiments of this disclosure, (a) and (b) are respectively a temperature control history diagram for calibrating the temperature coefficient of suspension electrode resistance and a diagram showing the relationship between suspension electrode resistance and temperature during the measurement of thermal conductivity using the above-described measuring device.

[0032] Figure 3 In the figure, (a), (b), (c), and (d) are respectively the voltage control process at both ends of the suspension electrode, the relationship between the resistance of the suspension electrode and the heating power of the suspension electrode, the relationship between the average temperature rise of the suspension electrode and the heating power of the suspension electrode, and the value of the thermal conductivity of the suspension electrode during the calibration process.

[0033] Figure 4 This is a graph showing the relationship between the average temperature rise of the suspension before and after the nanofibers are placed and the heating power of the suspension electrodes.

[0034] In the picture:

[0035] 1. Base; 11. First sidewall; 12. Second sidewall; 13. Third sidewall; 14. Fourth sidewall;

[0036] 21. First conductive electrode; 22. Second conductive electrode;

[0037] 3. Support layer;

[0038] 4. Adhesive layer;

[0039] 5. Suspension electrodes;

[0040] 6. Nanofibers. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0042] Conversely, this application covers any alternatives, modifications, equivalent methods, and schemes made within the spirit and scope of this application as defined by the claims. Furthermore, to provide the public with a better understanding of this application, certain specific details are described in detail below. However, this application can be fully understood by those skilled in the art even without these detailed descriptions.

[0043] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the foundation or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0045] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] See Figure 1 This disclosure provides a device for measuring the thermal conductivity of nanofibers. The nanofiber to be measured, 6, is a low thermal conductivity nanofiber, with a thermal conductivity not exceeding 10 W·(m·K). -1 The measuring device in this embodiment includes:

[0047] The base 1 has a hollowed-out center, and a first sidewall 11 and a second sidewall 12, as well as a third sidewall 13 and a fourth sidewall 14, are formed around the hollowed-out area.

[0048] The first conductive electrode 21 and the second conductive electrode 22 are respectively formed on the first sidewall 11 and the second sidewall 12 of the substrate;

[0049] The support layer 3, the adhesive layer 4, and the suspension electrode 5 are stacked sequentially from bottom to top. The suspension electrode 5 is supported by the support layer 3 on the first sidewall 11 and the second sidewall 12 of the substrate 1. An adhesive layer 4 is processed between the suspension electrode 5 and the support layer 3 to ensure good bonding between the two. The two ends of the suspension electrode 5 are connected to the first conductive electrode 21 and the second conductive electrode 22, respectively. Current is applied to the suspension electrode 5 through the first conductive electrode 21 and the second conductive electrode 22 to make the suspension electrode 5 a hot end. The thermal resistance of the suspension electrode 5 is greater than the thermal resistance of the nanofiber 6. The two ends of the nanofiber 6 are supported on the suspension electrode 5 and the fourth sidewall 14 of the substrate 1, respectively.

[0050] In some embodiments, the substrate 1 serves as the main support component and cold end of the measuring device, maintaining a consistent ambient temperature. The central hollow design ensures that the suspension electrode 5 only contacts the first conductive electrode 21 and the second conductive electrode 22 at its two ends, respectively. Other locations can be considered as adiabatic boundary conditions under vacuum, thus ensuring that the measurement results do not change due to the substrate being placed on different media, increasing the robustness of the measuring device. The substrate 1 is made of an insulating material; preferably, it can be formed by photolithography of silicon, silicon nitride, silicon oxide, gallium arsenide, germanium, or silicon carbide. In this embodiment, a silicon substrate with a central hollow design is used.

[0051] In some embodiments, the first conductive electrode 21 and the second conductive electrode 22 are made of conductive materials, and their thermal resistance should be much smaller than that of the nanofiber 6 to be measured. Therefore, the two conductive electrodes also serve as cold ends during the measurement process, consistent with the boundary conditions of the subsequent calculation model. In this embodiment, the two conductive electrodes are fabricated by magnetron sputtering and symmetrically disposed on the first sidewall 11 and the second sidewall 12 of the substrate 1 by ion beam etching.

[0052] In some embodiments, the suspension electrode 5, acting as a hot end during measurement, should be made of a conductive material with a thermal resistance higher than that of the nanofiber being measured. Furthermore, to obtain a good measurement signal-to-noise ratio, the thermal resistance of the suspension electrode 5 should be greater than or equal to 10% of the thermal resistance of the nanofiber 6. Even further, to balance good manufacturability with high thermal resistance requirements, the length of the suspension electrode 5 should not exceed 250 μm, and the cross-sectional area through which the current flows should not exceed 2.5 μm. 2The lower limits of the length of the suspension electrode 5 and the cross-sectional area through which the current flows are determined by the manufacturing process. The distance between the suspension electrode 5 and the fourth sidewall 14 of the substrate 1 does not exceed 25 μm to ensure that the fiber thermal resistance does not exceed the accurate measurement range of the device. Furthermore, the material used to manufacture the suspension electrode 5 should also meet the requirement that the suspension electrode will not crack due to thermal expansion during heating; furthermore, the coefficient of thermal expansion of the material used to manufacture the suspension electrode 5 does not exceed 1.8 × 10⁻⁶. -5 ℃ -1 In this embodiment, the suspension electrode 5 is made of gold, with a coefficient of thermal expansion of 1.42 × 10⁻⁶. -5 ℃ -1 The suspension electrode 5 has a length of 200 μm (i.e., the dimension along the distance from the first sidewall to the second sidewall), a width of 4 μm (i.e., the dimension along the distance from the third sidewall to the fourth sidewall), and a thickness of 250 nm (i.e., the dimension along the stacking direction from the suspension electrode 5 to the support layer 3). The gold electrode is fabricated by magnetron sputtering, with a power control of 500 W and a sputtering rate control of 0.25 nm / min. The distance between the suspension electrode 5 and the fourth sidewall 14 is 20 μm.

[0053] In some embodiments, due to the relatively weak mechanical strength of the suspension electrode 5, a support layer 3 is provided below the suspension electrode 5 to ensure its mechanical strength and prevent it from breaking or detaching from the conductive electrode due to device vibration, temperature changes, or thermal stress during measurement. To balance good machinability with support layer strength, the thickness of the support layer 3 is not less than 150 μm, and the distance between the bottom of the support layer 3 and the bottom of the device (i.e., the bottom of the substrate) should be greater than or equal to 200 μm. Furthermore, the coefficient of thermal expansion of the material used to make the support layer 3 does not exceed 1.8 × 10⁻⁶. -5 ℃ -1 To prevent the support layer from cracking due to thermal expansion during heating, in this embodiment, the support layer 3 is made of silicon nitride, which has a coefficient of thermal expansion of 3.2 × 10⁻⁶. -6 ℃ -1 The support layer 3 has a length of 200 μm, a width of 4 μm, and a thickness of 200 nm. The support layer 3 is prepared by low-pressure chemical vapor deposition, with specific parameters including: the gases used are NH3 (flow rate of 280 mL / min) and SiH2Cl2 (flow rate of 70 mL / min), the temperature is 800 °C, and the growth rate is 4 nm / min.

[0054] In some embodiments, the adhesive layer 4 is used to enhance the interaction between the support layer 3 and the suspension electrode 5, further improving the mechanical strength and durability of the suspension electrode 5, and is generally made of a metallic material. In this embodiment, the adhesive layer 4 is made of chromium, with a coefficient of thermal expansion of 4.9 × 10⁻⁶. -6 ℃ -1The adhesion layer 4 has a length of 200 μm, a width of 4 μm, and a thickness of 50 nm. The adhesion layer 4 was prepared by magnetron sputtering at a power of 200 W and a sputtering rate of 0.12 nm / min.

[0055] The preparation process of the measuring device in this embodiment is as follows:

[0056] 1) Cleaning silicon substrates by plasma: the gas atmosphere is oxygen, the plasma source power is 400W, and the pressure is 80mTorr;

[0057] 2) Design and fabricate electrode photolithography masks;

[0058] 3) Fabrication of silicon nitride support layer by magnetron sputtering: The gases used were NH3 (flow rate of 280 mL / min) and SiH2Cl2 (flow rate of 70 mL / min), the temperature was 800℃, and the growth rate was 4 nm / min;

[0059] 4) A chromium adhesion layer was fabricated by magnetron sputtering: power 200W, speed 0.12nm / min, thickness 50nm;

[0060] 5) Fabrication of gold suspension electrodes by magnetron sputtering: power 500W, speed 0.25nm / min, thickness 250nm;

[0061] 6) Remove some unwanted silicon substrate by photolithography: Expose with MA6 broadband light source for 7s, develop with 2.38% TMAH developer for 45s;

[0062] 7) Obtain the desired suspension electrode, adhesion layer, support layer and conductive electrode structure by ion beam etching: ion energy: 300eV, beam current: 802mA, neutralization current: 100mA;

[0063] 8) Remove the adhesive backing by ultrasonic cleaning, using acetone and isopropanol as solvents;

[0064] 9) Design and fabricate a back-side overprinting mask;

[0065] 10) Back cover photolithography.

[0066] This disclosure also proposes a method for measuring the thermal conductivity of nanofibers using the above-described device. During measurement, the device needs to be placed in a vacuum environment, and the ambient temperature, typically 20–30°C, must be recorded. The measurement method specifically includes the following steps:

[0067] 1) The temperature coefficient of resistance of the suspension electrode 5 is calibrated to determine the relationship between the resistance of the suspension electrode and temperature. Specifically, the temperature is controlled by a sample stage with a vacuum chamber, and the resistance of the suspension electrode 5 at different temperatures is measured. The measurement results in this embodiment are as follows: Figure 2 As shown, Figure 2 Figures (a) and (b) show the temperature control history diagram and the relationship between the suspension electrode resistance and temperature, respectively, of the measurement device provided in this embodiment for calibrating the temperature coefficient of the suspension electrode resistance. The results show that the resistance of the gold suspension electrode has a linear relationship with temperature, y = 1.0506x + 862.07, and its linearity R... 2 =1.0000, where y represents resistance and x represents temperature. The resistance measurement has a small error bar, and the metal suspension electrode has good electrical characteristics.

[0068] 2) The thermal conductivity of the suspension electrodes is calibrated according to the following formula based on the relationship between the resistance and temperature of the suspension electrodes:

[0069]

[0070] Where λ is the thermal conductivity of the suspension electrode, q v Let t be the heating power of the suspension electrode, L be the length of the suspension electrode, t be the average temperature of the suspension electrode, and t0 be the ambient temperature. This is the average temperature rise of the suspension electrodes.

[0071] The specific operating procedure is as follows: First, different voltages are applied to both ends of the suspension electrode 5 through conductive electrodes 21 and 22, and the current through the suspension electrode 5 is measured. Each voltage is stabilized for 5 minutes. Figure 3 As shown in (a); the resistance of suspension electrode 5 over time was calculated according to Ohm's law, and the resistance measurements over the last 2 minutes were averaged to obtain the relationship between the resistance of suspension electrode 5 and heating power, as shown in Figure (a). Figure 3 As shown in (b), the suspension electrode heating power x and suspension electrode heating power y satisfy the relationship: y = 3.1613x + 886.93, and its linearity R 2 =0.9999; Based on the relationship between suspension electrode resistance and temperature obtained in step 1), calculate the relationship between the average temperature rise y of the suspension electrode and the heating power x, as shown in the figure. Figure 3 As shown in (c), the suspension electrode heating power x and the average temperature rise y of the suspension electrode satisfy the relationship: y = 3.0100x, and its linearity R 2 =0.9999; Finally, the thermal conductivity of the suspension electrode is calculated according to formula (1), such as Figure 3 As shown in (d).

[0072] 3) Using a micro-operating system, place one end of the nanofiber 6 to be tested at the center of the suspension electrode 5, and the other end at the center of the fourth sidewall 14 of the substrate 1. The nanofiber used is a perfluorosulfonic acid resin fiber with a diameter of 430 nm. Referring to step 2), calculate the relationship between the average temperature rise of the suspension electrode and the heating power under different heating powers, as shown in the figure. Figure 4As shown. Through derivation using a one-dimensional thermal conductivity model, it can be seen that the temperature rise of the suspension electrode after placing the nanofibers satisfies:

[0073]

[0074] Among them, W f H represents the width of nanofiber 6. f λ is the thickness of nanofiber 6 (the cross-section of the nanofiber is simplified to a rectangle here), W is the width of suspension electrode 5, H is the thickness of suspension electrode 5, and λ is the thickness of nanofiber 6. f The thermal conductivity of nanofiber 6 is given.

[0075] 4) Based on the thermal conductivity of the suspension electrode calibrated in step 2) and the temperature rise requirement of the suspension electrode obtained in step 3), i.e., by combining formulas (1) and (2), the thermal conductivity of the nanofiber can be calculated to be 2.5 W·(m·K). -1 This is far higher than the thermal conductivity of the ionomer film, which is 0.2 W·(m·K). -1 .

[0076] It is understood that the nanofiber thermal conductivity measuring device and method provided in this embodiment can accurately and effectively measure the thermal conductivity of low thermal conductivity nanofibers, solving the problem of low accuracy in measuring the thermal conductivity of low thermal conductivity nanofibers such as organic polymer nanofibers.

[0077] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0078] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A device for measuring the thermal conductivity of nanofibers, characterized in that, include: The base has a hollowed-out center, and a first sidewall and a second sidewall, as well as a third sidewall and a fourth sidewall, are formed around the hollowed-out area. The first conductive electrode and the second conductive electrode are respectively formed on the first sidewall and the second sidewall; as well as The structure consists of a support layer, an adhesive layer, and a suspension electrode stacked sequentially from bottom to top. The suspension electrode is supported by the support layer on the first and second sidewalls. Both ends of the suspension electrode are connected to the first and second conductive electrodes, respectively. Current is applied to the suspension electrode through the first and second conductive electrodes, making the suspension electrode a hot end. Both ends of the nanofiber are supported on the suspension electrode and the fourth sidewall, respectively. The thermal resistance of the suspension electrode should be greater than or equal to 10% of the thermal resistance of the nanofiber. The length of the suspension electrode does not exceed 250 μm, and the cross-sectional area through which the current flows does not exceed 2.5 μm. 2 The distance between the suspension electrode and the fourth sidewall does not exceed 25 μm.

2. The measuring device according to claim 1, characterized in that, The coefficient of thermal expansion of the material used to manufacture the suspension electrode does not exceed 1.8 × 10⁻⁶. -5 ℃ -1 The coefficient of thermal expansion of the material used to make the support layer does not exceed 1.8 × 10⁻⁶. -5 ℃ -1 .

3. The measuring device according to claim 1, characterized in that, The adhesive layer is made of metal and is used to ensure the bonding between the suspension electrode and the support layer.

4. The measuring device according to claim 1, characterized in that, The distance from the bottom of the support layer to the bottom of the substrate should be greater than or equal to 200 μm.

5. The measuring device according to claim 1, characterized in that, The substrate is made of insulating material, and the temperature of the substrate is kept consistent with the ambient temperature.

6. The measuring device according to any one of claims 1 to 5, characterized in that, The thermal conductivity of the nanofibers does not exceed 10 W·(m·K). -1 .

7. A measurement method using the measuring device according to any one of claims 1 to 6, characterized in that, include: 1) Calibrate the temperature coefficient of resistance of the suspension electrode to determine the relationship between the resistance of the suspension electrode and temperature; 2) Based on the relationship between the resistance and temperature of the suspension electrodes, the thermal conductivity of the suspension electrodes is calibrated according to the following formula: in, The thermal conductivity of the suspension electrode. This refers to the heating power of the suspension electrodes. The length of the suspension electrode. The average temperature of the suspension electrodes. For ambient temperature, This is the average temperature rise of the suspension electrodes; 3) The two ends of the nanofiber are supported on the suspension electrode and the fourth sidewall, respectively. Based on the relationship between the average temperature rise of the suspension electrode and the heating power under different heating powers, and using a one-dimensional thermal conductivity model, the average temperature rise of the suspension electrode after placing the nanofiber should satisfy the following formula: in, The width of the nanofiber. The thickness of the nanofibers. The width of the suspension electrode. The thickness of the suspension electrode. The thermal conductivity of nanofibers; 4) Combine formulas (1) and (2) to calculate the thermal conductivity of the nanofiber.

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