Flexible wearable thermosensitive fibers, their preparation methods and applications

Abstract

This invention relates to a flexible wearable thermosensitive fiber, its preparation method, and its applications. The flexible wearable thermosensitive fiber includes a conductive fiber and a thermosensitive coating, an external electrode layer, and an encapsulation protective layer sequentially coated on the outer surface of any one end of the conductive fiber. The conductive fiber and the external electrode layer are not in contact. An insulating layer is also disposed between the thermosensitive coating and the external electrode layer within the axial projection area of ​​the conductive fiber. The thermosensitive coating is based on a polymer matrix, and the matrix includes a thermosensitive material. The flexible wearable thermosensitive fiber also includes a detection end lead, which penetrates the encapsulation protective layer and forms an electrical connection with the external electrode layer. This flexible wearable thermosensitive fiber has low resistance and excellent mechanical properties, enabling sensitive, accurate, and rapid temperature detection. Wearable temperature sensors made from this flexible wearable thermosensitive fiber can be well applied in the medical field for body temperature detection.

Description

Technical Field

[0001] This invention relates to the field of temperature sensing equipment technology, and in particular to a flexible wearable thermosensitive fiber, its preparation method, and its application. Background Technology

[0002] Body temperature is an important indicator of human health. Continuous, non-invasive monitoring of postoperative patients' body temperature using wearable temperature sensors can improve recovery and reduce mortality. Additionally, wearable temperature sensors can monitor blood and respiratory airflow through calorimetric flow monitoring. Because body temperature fluctuates relatively little, wearable temperature sensors used for detection should be soft, flexible, highly sensitive, biocompatible, lightweight, naturally adhere to the skin surface, and have sufficiently high resolution.

[0003] Based on different response principles, temperature-sensitive materials can be divided into thermistors, thermal resistance materials, and thermocouples. Among them, negative temperature coefficient (NTC) thermistors, represented by metal oxides, carbon-based materials, and conductive polymers, have higher sensitivity, resistivity far exceeding that of wires, and more economical costs, greatly lowering the barrier to entry for wearable temperature sensors. However, the sensing layer in traditional wearable temperature sensors, such as the nickel oxide sensing layer, is easily affected by external forces such as strain and pressure, causing errors in temperature measurement. In addition, traditional wearable temperature sensors use planar polymer substrates, which, due to their density, suffer from poor breathability, reducing wearing comfort. Summary of the Invention

[0004] Therefore, it is necessary to address the above-mentioned problems by providing a flexible wearable thermal fiber, its preparation method, and its application. This flexible wearable thermal fiber has excellent mechanical properties and can detect temperature sensitively, accurately, and quickly. Wearable temperature sensors made from this flexible wearable thermal fiber can be well applied in the medical field for body temperature detection.

[0005] This invention discloses a flexible wearable thermosensitive fiber, comprising a conductive fiber and a thermosensitive coating, an external electrode layer, and an encapsulation protective layer sequentially covering the outer surface of any one end of the conductive fiber. The conductive fiber and the external electrode layer do not contact each other. An insulating layer is further disposed between the thermosensitive coating and the external electrode layer within the axial projection area of ​​the conductive fiber. The thermosensitive coating is based on a polymer matrix, and the matrix includes a thermosensitive material.

[0006] The flexible wearable thermal fiber also includes a detection end lead wire, which penetrates the encapsulation protective layer and forms an electrical connection with the outer electrode layer.

[0007] In one embodiment, the thermosensitive material includes at least one of nano-nickel oxide, reduced graphene oxide, or copper oxide; the polymer includes at least one of polyimide, polyurethane, polyethylene terephthalate, or polyvinylidene fluoride.

[0008] And / or, the mass fraction of the thermosensitive material in the thermosensitive coating is 20%-50%.

[0009] In one embodiment, the thickness of the thermal coating is 10μm-100μm, and the diameter of the conductive fiber is 0.1mm-0.2mm.

[0010] In one embodiment, the flexible wearable thermosensitive fiber further includes an electrical signal output lead wire, which forms an electrical connection with the other end of the conductive fiber away from the thermosensitive coating.

[0011] In one embodiment, the conductive fiber is selected from tungsten wire, copper wire, stainless steel wire, carbon fiber, copper-plated nylon, or silver-plated nylon.

[0012] A method for preparing flexible wearable thermosensitive fibers as described above, characterized by comprising the following steps:

[0013] One end of a conductive fiber is immersed in a composite ink for coating and lifting, and then cured to form a thermosensitive coating. The end with the thermosensitive coating is the detection end of the conductive fiber. The composite ink is obtained by mixing a thermosensitive material with a polymer solution.

[0014] An insulating layer is formed on the surface of the thermosensitive coating, and the insulating layer is located within the axial projection area of ​​the conductive fiber;

[0015] The detection end of the conductive fiber is immersed in conductive silver paste for coating and lifting, without the conductive silver paste contacting the conductive fiber. After removal, the detection end lead is attached to the conductive silver paste on the surface of the conductive fiber, and then cured to form an external electrode layer. Simultaneously, the detection end lead is electrically connected to the external electrode layer.

[0016] The detection end of the conductive fiber is immersed in a polysiloxane solution, and then removed and cured to form an encapsulation protective layer.

[0017] In one embodiment, in the step of immersing any end of the conductive fiber into the composite ink for coating and pulling, the pulling speed is 15 mm / min-40 mm / min.

[0018] In one embodiment, the composite ink further satisfies at least one of the following conditions:

[0019] (1) The mass ratio of the thermosensitive material to the polymer solution is 20:79.95-50:49.9;

[0020] (2) The polymer solution comprises a polymer and an organic solvent, wherein the mass ratio of the polymer to the organic solvent is 1:5 to 1:8, and the organic solvent comprises at least one of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, triethyl phosphate or dimethyl sulfoxide.

[0021] (3) The composite ink also includes a surfactant, which includes at least one of cetyltrimethylammonium bromide, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyoxyethylene stearate or polyethylene glycol dioleate, and the mass ratio of the surfactant to the thermosensitive material is 0.05:20-0.1:50.

[0022] An application of a flexible wearable thermal fiber, as described above, in a wearable temperature sensor.

[0023] A wearable temperature sensor includes a flexible wearable thermal fiber as described above and a non-conductive bandage. The two ends of the flexible wearable thermal fiber penetrate from the same side of the non-conductive bandage and are fixed to the surface of the non-conductive bandage by a connecting module.

[0024] The flexible wearable thermosensitive fiber provided by this invention has several advantages. First, since the thermosensitive coating covers the outer surface of the conductive fiber, according to the formula R = ρ * L / S, reducing the thickness L of the thermosensitive coating and increasing the contact area S can effectively reduce the resistance R of the thermosensitive coating, facilitating detection. Second, the polymer in the thermosensitive coating increases its mechanical properties, especially its flexibility, thus reducing the interference of external forces on the temperature detection results. Third, the thermosensitive coating and the conductive fiber have good heat resistance, expanding the temperature detection range and making the flexible wearable thermosensitive fiber suitable for various detection environments. The thermosensitive material in the thermosensitive coating has high temperature sensitivity, improving the accuracy and sensitivity of temperature measurement. In addition, the encapsulation protective layer can block interfering substances such as water vapor, increasing the stability of the response of the flexible wearable thermosensitive fiber. In summary, the flexible wearable thermosensitive fiber provided by this invention has the advantages of easy storage and use, fast response, and good stability. It can detect temperature sensitively, accurately, and quickly, and can be well applied in the medical field, such as realizing long-term real-time monitoring of body surface temperature.

[0025] When the flexible wearable thermal fiber provided by this invention is applied to a wearable temperature sensor, the wearable temperature sensor can be prepared by weaving and fixed to the skin surface by a non-conductive bandage. In addition to sensitive, accurate and fast temperature detection, it also increases wearing comfort and breathability. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a flexible wearable thermosensitive fiber according to an embodiment of the present invention;

[0028] Figure 2 This is a cross-sectional view of a wearable temperature sensor according to an embodiment of the present invention.

[0029] Figure 3 This is a front view of a wearable temperature sensor according to an embodiment of the present invention.

[0030] Figure 4 This is a side view of a wearable temperature sensor according to an embodiment of the present invention.

[0031] Figure 5 The resistance response calibration curves of the wearable temperature sensor provided in Example 1 at different temperatures;

[0032] Figure 6 The resistance change curve of the wearable temperature sensor provided in Example 1 under bending conditions;

[0033] Figure 7 The resistance change curve of the wearable temperature sensor provided in Example 1 under pressure;

[0034] Figure 8 The response repeatability curve of the wearable temperature sensor provided in Example 1 during the heating and cooling cycle;

[0035] Figure 9 The resistance response diagram of the wearable temperature sensor provided in Example 1 to water cups at different temperatures.

[0036] In the diagram: 10, conductive fiber; 20, encapsulation protective layer; 30, external electrode layer; 40, thermosensitive coating; 50, insulating layer; 60, non-conductive bandage; 70, connecting module; 80, electrical signal output lead; 90, detection lead. Detailed Implementation

[0037] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0039] like Figure 1 The diagram shows the structure of the flexible wearable thermosensitive fiber provided by the present invention. It includes a conductive fiber 10 and a thermosensitive coating 40, an outer electrode layer 30, and an encapsulation protective layer 20 sequentially covering the outer surface of any one end of the conductive fiber 10. The conductive fiber 10 and the outer electrode layer 30 are not in contact. An insulating layer 50 is also provided between the thermosensitive coating 40 and the outer electrode layer 30 in the axial projection area of ​​the conductive fiber 10. The thermosensitive coating 40 is based on a polymer and includes a thermosensitive material in the matrix. The flexible wearable thermosensitive fiber also includes a detection end lead 90, which penetrates the encapsulation protective layer 20 and forms an electrical connection with the outer electrode layer 30.

[0040] It should be noted that the insulating layer 50 can prevent the outer electrode layer 30 from short-circuiting with the conductive fiber 10, which serves as the inner electrode layer. Considering that the tip of the conductive fiber 10 is most prone to short-circuiting with the outer electrode layer 30 due to uneven coating of the thermosensitive coating 40, the insulating layer 50 is disposed between the thermosensitive coating 40 and the outer electrode layer 30, and within the axial projection area of ​​the conductive fiber 10.

[0041] First, in the flexible wearable thermosensitive fiber provided by the present invention, since the thermosensitive coating 40 covers the outer surface of the conductive fiber 10, the ratio of the thickness of the thermosensitive coating 40 to the cross-sectional area per unit volume is reduced. According to the formula R=ρ*L / S, by reducing the thickness L of the thermosensitive coating and increasing the contact area S, the resistance value R of the thermosensitive coating can be effectively reduced, which facilitates detection.

[0042] Secondly, the thermosensitive coating 40 in the flexible wearable thermosensitive fiber of this invention uses a polymer matrix, and the matrix includes a thermosensitive material. The polymer matrix in the thermosensitive coating 40 increases the mechanical properties of the thermosensitive coating 40, especially its flexibility, thus reducing the interference of external forces on the temperature detection results. Thirdly, the thermosensitive coating 40 and the conductive fiber 10 have good heat resistance, expanding the temperature detection range and enabling the flexible wearable thermosensitive fiber to be suitable for various detection environments. The thermosensitive material in the thermosensitive coating 40 has high temperature sensitivity, improving the accuracy and sensitivity of temperature measurement.

[0043] In addition, the encapsulation protective layer 20 can block interfering substances such as moisture, increasing the stability of the flexible wearable thermosensitive fiber response.

[0044] In one embodiment, the thermistor material includes at least one of nano-nickel oxide, reduced graphene oxide, or copper oxide; preferably, the thermistor material includes nano-nickel oxide because nano-nickel oxide has a high temperature coefficient of resistance and excellent chemical stability.

[0045] In order to enable the thermosensitive coating 40 to have excellent mechanical properties and to detect temperature sensitively, accurately and quickly, the mass fraction of the thermosensitive material in the thermosensitive coating 40 is 20%-50%, including but not limited to 20%, 25%, 30%, 35%, 40%, 45% or 50%.

[0046] In one embodiment, the polymer includes at least one of polyimide, polyurethane, polyethylene terephthalate, or polyvinylidene fluoride.

[0047] To further reduce the resistance of the thermistor coating 40 and make it easier to detect, the thickness of the thermistor coating 40 is 10μm-100μm, including but not limited to 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm or 100μm.

[0048] In order to make the thermal coating 40 on the surface of the conductive fiber 10 more uniform, preferably, the diameter of the conductive fiber 10 is 0.1mm-0.2mm, including but not limited to 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm or 0.20mm.

[0049] In one embodiment, the conductive fiber 10 is selected from tungsten wire, copper wire, stainless steel wire, carbon fiber, copper-plated nylon, or silver-plated nylon.

[0050] In one embodiment, the flexible wearable thermal fiber also includes an electrical signal output lead 80, which is electrically connected to the other end of the conductive fiber 10 away from the thermal coating 40. It should be noted that when the length of the conductive fiber 10 is sufficient to connect to the source meter for measuring the resistance value, the end of the conductive fiber 10 away from the thermal coating 40 can be directly used as the electrical signal output lead 80.

[0051] In summary, the flexible wearable thermosensitive fiber provided by this invention has the advantages of being easy to store and use, having a fast response and good stability. It can detect temperature sensitively, accurately and quickly, and can be well applied in the medical field, such as realizing long-term real-time monitoring of body surface temperature.

[0052] The present invention also provides a method for preparing the flexible wearable thermosensitive fiber as described above, comprising the following steps:

[0053] S10, any one end of the conductive fiber 10 is immersed in the composite ink for coating and lifting, and then cured to form a thermal coating 40, wherein the end with the thermal coating 40 is the detection end of the conductive fiber 10.

[0054] S20, an insulating layer 50 is formed on the surface of the thermal coating 40, and the insulating layer 50 is in the axial projection area of ​​the conductive fiber 10.

[0055] S30, the detection end of the conductive fiber 10 is immersed in conductive silver paste for coating and lifting, without the conductive silver paste contacting the conductive fiber 10. After removal, the detection end lead 90 is attached to the conductive silver paste on the surface of the conductive fiber 10, and then cured to form the outer electrode layer 30, while simultaneously making the detection end lead 90 electrically connected to the outer electrode layer 30; and

[0056] S40, one end of the conductive fiber 10 with the thermosensitive coating 40 is immersed in a polysiloxane solution, and then cured to form an encapsulation protective layer 20.

[0057] In step S10, before immersing any end of the conductive fiber 10 into the composite ink for coating and lifting, the conductive fiber 10 is first subjected to pretreatment and surface silanization treatment in sequence. The pretreatment of the conductive fiber 10 can remove impurities on the surface of the conductive fiber 10, and the surface silanization treatment of the conductive fiber 10 can improve the adhesion between the composite ink and the conductive fiber 10, thereby forming a firm and stable thermal coating 40 on the surface of the conductive fiber 10.

[0058] In one embodiment, the pretreatment of the conductive fiber 10 specifically includes the following steps: first, immersing the conductive fiber 10 in a 50 vol%-60 vol% ethanol solution for ultrasonic cleaning, then rinsing it with deionized water, and then immersing it in a 5.0 wt%-10.0 wt% dilute sulfuric acid solution for ultrasonic cleaning, then rinsing it with deionized water, and finally drying it.

[0059] In one embodiment, the surface silanization treatment of the conductive fiber 10 specifically includes the following steps: immersing one end of the conductive fiber 10 in a silane mixture solution for 3-5 seconds, then removing it and air-drying it, repeating this process several times, and finally placing the conductive fiber 10 in a drying oven to dry it, forming a silane film at one end of the conductive fiber 10. It should be noted that the thermosensitive coating 40 is formed on the end of the conductive fiber 10 with the silane film.

[0060] In one embodiment, the silane mixture includes water, ethanol, and a silanizing agent; including but not limited to, the silanizing agent including at least one of 1,1,1,3,3,3-hexamethyldisilane, bis(trimethylsilyl)trifluoroacetamide, N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide, or trimethylsilane imidazole; preferably, the mass ratio of water, ethanol, and silanizing agent is (80-90):(5-15):(1-5).

[0061] The composite ink is obtained by mixing a thermosensitive material with a polymer solution. Preferably, the mass ratio of the thermosensitive material to the polymer solution is 20:79.95-50:49.9, including but not limited to 20:79, 30:70, 40:60 or 50:49.9, so that the thermosensitive coating 40 has both excellent mechanical properties and sensitive, accurate and fast temperature detection performance.

[0062] The polymer solution includes a polymer and an organic solvent. In order to disperse the heat-sensitive material and the polymer more uniformly in the composite ink, in one embodiment, the organic solvent includes at least one of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, triethyl phosphate, or dimethyl sulfoxide. Preferably, the mass ratio of the polymer to the organic solvent is 1:5 to 1:8, including but not limited to 1:5, 1:6, 1:7, or 1:8.

[0063] To further improve the uniformity of dispersion of the thermosensitive material in the composite ink, the composite ink also includes a surfactant, which includes at least one of cetyltrimethylammonium bromide, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyoxyethylene stearate, or polyethylene glycol dioleate. The mass ratio of the surfactant to the thermosensitive material is 0.05:20-0.1:50.

[0064] In one embodiment, the surfactant is added to the composite ink in the form of an aqueous surfactant solution, the concentration of which is 0.1 mol / L to 1 mol / L.

[0065] In order to control the resistance value and coating uniformity of the thermal coating 40, in the step of immersing any end of the conductive fiber 10 into the composite ink for coating and lifting, the lifting speed is 15mm / min-40mm / min, including but not limited to 15mm / min, 20mm / min, 25mm / min, 30mm / min, 35mm / min or 40mm / min.

[0066] The specific steps for curing to form the heat-sensitive coating 40 include placing the conductive fiber 10 in an oven for curing and drying at a temperature of 80℃-120℃.

[0067] In step S20, the step of forming an insulating layer 50 on the surface of the thermal coating 40 may include applying an adhesive to the tip of the conductive fiber 10 with the thermal coating 40, and then placing the conductive fiber 10 in an oven for drying at a temperature of 75°C-85°C for 0.3h-0.7h.

[0068] In step S30, the step of curing to form the outer electrode layer 30 may include placing the conductive fiber 10 in an oven for curing and drying at a temperature of 75℃-85℃ for 0.5h-1.5h.

[0069] Step S40: The polysiloxane solution includes polysiloxane and a crosslinking curing agent. In one embodiment, the polysiloxane includes at least one of polydimethylsiloxane, polymethylphenylsiloxane, aminosiloxane, and cyclomethylsiloxane; the crosslinking curing agent includes at least one of diphenylcarbamate, methyltriethoxysilane, methyltripropoxysilane, and methyltributyl ketone oxime silane. To make the encapsulation protective layer 20 more dense, thereby better isolating interfering substances such as moisture and improving the compatibility between the flexible wearable thermal fiber and human skin, the mass ratio of polysiloxane to crosslinking curing agent is 10:1 to 30:1, including but not limited to 10:1, 15:1, 20:1, 25:1, or 30:1.

[0070] In one embodiment, the step of curing to form the encapsulation protective layer 20 specifically includes: placing the conductive fiber 10 in an oven for curing at a temperature of 70°C-90°C for 0.5h-1.5h.

[0071] To prevent premature cross-linking reaction between polysiloxane and cross-linking curing agent, the polysiloxane and cross-linking curing agent are mixed, stirred evenly at room temperature, and then stored at 1℃-8℃.

[0072] The present invention also provides an application of the flexible wearable thermal fiber as described above in a wearable temperature sensor.

[0073] When the flexible wearable thermal fiber provided by this invention is applied to a wearable temperature sensor, the wearable temperature sensor can be prepared by weaving and fixed to the skin surface by a non-conductive bandage 60. In addition to sensitive, accurate and fast temperature detection, it also increases wearing comfort and breathability.

[0074] The present invention also provides a wearable temperature sensor, including the flexible wearable thermal fiber as described above and a non-conductive bandage 60. The two ends of the flexible wearable thermal fiber penetrate the non-conductive bandage 60 from the same side and are fixed to the non-conductive bandage 60 by a connecting module 70.

[0075] In order to better fix the flexible wearable thermal fiber to the non-conductive bandage 60 and reduce the interference of the displacement of the flexible wearable thermal fiber on the experimental results during the test, preferably, the connecting module 70 is fixed to the surface of the non-conductive bandage 60 by AB glue.

[0076] The following specific examples will further illustrate flexible wearable thermosensitive fibers, their preparation methods, and applications.

[0077] Example 1

[0078] One end of a 0.2 mm diameter, 99.99% pure tungsten wire was fixed, and the other end was immersed in a 55 vol% alcohol solution for ultrasonic cleaning. After 1 minute, it was rinsed with deionized water and then immersed in a 7.5 wt% dilute sulfuric acid solution for ultrasonic cleaning. After 1 minute, it was rinsed with deionized water. The ultrasonic cleaning power was 180 W. The wire was then placed in a drying oven to dry for 1 day.

[0079] According to a volume ratio of 1:9:90, silanizing reagent 1,1,1,3,3,3,-hexamethyldisilane and anhydrous ethanol were added to deionized water and stirred evenly to prepare a silane mixed solution. One end of conductive fiber 10 was immersed in the silane mixed solution, and after 3 seconds it was taken out and dried. After repeated immersion and coating 3 times, it was placed in an oven at 100℃ and dried for 1 hour to form a transparent silane film on the surface of conductive fiber 10.

[0080] 1g of polyimide was dissolved in 7g of dimethylformamide and mixed thoroughly by shaking to obtain a transparent and viscous polyimide film solution. 500mg of nickel oxide nanoparticles (McLean, 30nm diameter, 99.5% purity) and 7.5mg of a 0.1mol / L aqueous solution of the surfactant cetyltrimethylammonium bromide were dissolved in the 1g polyimide film solution and mixed thoroughly to prepare a thermosensitive composite ink. One end of the conductive fiber 10, after silanization treatment, was immersed in the composite ink for coating and pulling at a speed of 20mm / min. The fibers were then placed in an oven and cured and dried at 80℃ and 120℃ for 1 hour respectively, forming a thermosensitive coating 40 on the surface of the conductive fiber 10, resulting in a uniform black thermosensitive coating 40.

[0081] Liquid adhesive is applied to the tip of the heat-sensitive coating 40 and dried in an oven at 80°C for 0.5 hours. After drying, an insulating layer 50 is formed, which is located within the axial projection area of ​​the conductive fiber 10.

[0082] One end of the conductive fiber 10 coated with the thermosensitive coating 40 and the insulating layer 50 is immersed in conductive silver paste for coating and lifting. During the immersion process, the thermosensitive coating 40 is controlled to not be completely covered by the outer electrode layer 30. The outer electrode layer 30 is connected to one end of the detection terminal lead 90 through conductive silver paste, and then placed in an 80°C oven for curing and drying for 1 hour to obtain a uniform outer electrode layer 30.

[0083] Polydimethylsiloxane and diphenylcarbamate (DPC) were mixed at a mass ratio of 10:1 to form a viscous liquid. The mixture was stirred for 5 minutes to prepare a polymer membrane solution. After refrigerating the solution for 1 day, one end of the conductive fiber 10 coated with the outer electrode layer 30 was immersed in the polymer membrane solution to completely cover the outer electrode layer 30 and the thermal coating 40 of the conductive fiber 10. The solution was then cured in an 80°C oven for 1 hour to form a uniform and transparent encapsulation protective layer 20. This yielded a flexible wearable thermal fiber. The end of the flexible wearable thermal fiber without the thermal coating 40 served as the electrical signal output end.

[0084] Two connecting modules 70 are provided on the surface of the non-conductive bandage 60. The electrical signal output terminal and detection terminal lead-out line 90 of the thermal fiber pass through the non-conductive bandage 60 from the same side. The detection terminal lead-out line 90 of the thermal fiber is fixed by the connecting modules 70. The electrical signal output terminal of the thermal fiber is connected to the electrical signal output terminal lead-out line 80 through the connecting modules 70. Finally, the connecting modules 70 and the non-conductive bandage 60 are fixed together with AB glue to obtain a wearable temperature sensor for temperature detection. A cross-sectional view of the wearable temperature sensor is shown below. Figure 2 As shown, the front view is as follows Figure 3 As shown, the side view is as follows Figure 4 As shown.

[0085] When using a wearable temperature sensor for temperature measurement, a non-conductive bandage 60 is used to fix the flexible wearable thermal fiber to the surface of the object being measured, ensuring close contact between the flexible wearable thermal fiber and the surface. A source meter is connected to the detection lead 90 and the electrical signal output lead 80 of the flexible wearable thermal fiber to measure the resistance value of the flexible wearable thermal fiber, and the recording time is 60 seconds. The resistance value and the temperature of the surface of the object being measured exhibit an exponential function correlation. The temperature of the surface of the object being measured can be calculated based on the change in resistance value measured by the instrument.

[0086] Test case

[0087] Calibration curves of flexible wearable thermosensitive fibers for temperature detection

[0088] The flexible wearable thermosensitive fiber prepared in Example 1 was placed in a heating stage, and the resistance change characteristics of the thermosensitive fiber in the temperature range of 20℃-80℃ were recorded. The resistance response calibration curve is shown below. Figure 5 As shown, their linear relationship is Where R represents the resistance of the thermosensitive fiber, the temperature response sensitivity B is 3661K, T represents the absolute temperature of the thermosensitive fiber surface, and the correlation coefficient R0 is... 2 =0.9917.

[0089] Bending resistance test

[0090] During the use of wearable temperature sensors, the flexible wearable thermal fibers may bend and deform due to human movement or skin folds. A flexible stretching device was used to repeatedly push and pull the flexible wearable thermal fibers 500 times. The resistance change characteristics of the flexible wearable thermal fibers prepared in Example 1 of this invention were measured when the fibers were repeatedly bent 180° at room temperature. The test results are as follows: Figure 6 As shown.

[0091] Depend on Figure 6 It can be seen that the resistance change rate of the flexible wearable thermal fiber prepared in Example 1 when bent by 180° does not exceed 0.5%, and the temperature sensitivity of the flexible wearable thermal fiber at 25°C is >2.5%·°C. -1 It can be seen that the change in resistance caused by fiber bending will not cause significant error in temperature detection. Flexible wearable thermosensitive fibers have a certain degree of anti-interference against bending deformations common during wear.

[0092] Pressure resistance

[0093] Wearable temperature sensors may be subjected to various pressures such as squeezing and pressing during use, causing deformation of the flexible wearable thermal fibers. A 500g weight was used to apply pressure to the flexible wearable thermal fibers, and the resistance change characteristics caused by pressure at room temperature were measured using the flexible wearable thermal fibers prepared in Example 1 of this invention. The test results are as follows: Figure 7 As shown.

[0094] Depend on Figure 7 It is known that the resistance change rate of flexible wearable thermal fibers under the pressure of a 500g weight is no more than 0.2%, while the temperature sensitivity of flexible wearable thermal fibers at 25℃ is >2.5%·°C. -1 The experimental results show that the pressure applied during the wearing process does not cause significant errors in the temperature detection of flexible wearable thermosensitive fibers.

[0095] Repeatability test

[0096] Flexible wearable thermal fibers were placed in a heating platform and heated to temperatures of 20°C, 30°C, 40°C, 50°C, and 60°C, respectively. Then, the fibers were cooled to temperatures of 60°C, 50°C, 40°C, 30°C, and 20°C, respectively. The wearable temperature sensor prepared in Example 1 was used to measure the resistance values ​​corresponding to the temperature changes. Figure 8 As shown, the wearable temperature sensor exhibits good repeatability in its resistance response at the same temperature during both heating and cooling processes.

[0097] Response characteristics of objects at different temperatures

[0098] The wearable temperature sensor of Example 1 was fixed to the skin surface using a non-conductive bandage 60, and then the bandage 60 was brought into contact with cups containing warm water and hot water at 70°C, respectively. The change in resistance of the flexible wearable thermal fiber during contact and removal of the wearable temperature sensor from the cups at different temperatures is as follows: Figure 9 As shown, the sensor exhibits thermal sensitivity as the temperature of the object being measured changes, indicating that this flexible wearable thermal fiber can be used to measure changes in ambient temperature.

[0099] Comparative Example 1

[0100] Comparative Example 1 was conducted in accordance with Example 1, except that no insulating layer 50 was provided between the thermal coating 40 and the outer electrode layer 30. Testing of the flexible wearable thermal fiber obtained in Comparative Example 1 revealed a short circuit between the thermal coating 40 and the outer electrode layer 30, resulting in the flexible wearable thermal fiber exhibiting no significant temperature response characteristics.

[0101] Comparative Example 2

[0102] Comparative Example 2 was conducted in accordance with Example 1, except that the thermosensitive coating 40 was replaced with a copper oxide film. The flexible wearable thermosensitive fiber prepared in Comparative Example 2 was tested and found to have a temperature response sensitivity B value of 2105 K.

[0103] Example 2

[0104] One end of a copper wire with a diameter of 0.15 mm and a purity of 99.99% was fixed, and the other end was immersed in a 55 vol% alcohol solution for ultrasonic cleaning. After 1 minute, it was rinsed with deionized water and then immersed in a 7.5 wt% dilute sulfuric acid solution for ultrasonic cleaning. After 1 minute, it was rinsed with deionized water. The ultrasonic cleaning power was 180 W. The wire was then placed in a drying oven to dry for 1 day.

[0105] According to a volume ratio of 5:5:90, silanizing reagent 1,1,1,3,3,3,-hexamethyldisilane and anhydrous ethanol were added to deionized water and stirred evenly to prepare a silane mixed solution. One end of conductive fiber 10 was immersed in the silane mixed solution, and after 3 seconds it was taken out and dried. After repeated immersion and coating 3 times, it was placed in a 100℃ oven to dry for 1 hour, forming a transparent silane film on the surface of conductive fiber 10.

[0106] 1g of polyurethane was dissolved in 7g of dimethylformamide and mixed thoroughly by shaking to obtain a transparent and viscous polyurethane film solution. 600mg of nickel oxide nanoparticles and 7.5mg of a 0.1mol / L surfactant, hexadecyltrimethylammonium bromide aqueous solution, were dissolved in 1g of the polyurethane film solution and stirred thoroughly to prepare a thermosensitive composite ink. One end of a conductive fiber 10, after silanization treatment, was immersed in the composite ink for coating and pulling at a speed of 25mm / min. The fiber was then placed in an oven and cured and dried at 80℃ and 120℃ for 1 hour respectively, forming a thermosensitive coating 40 on the surface of the conductive fiber 10, resulting in a uniform black thermosensitive coating 40.

[0107] Liquid adhesive is applied to the tip of the heat-sensitive coating 40 and dried in an oven at 80°C for 0.5 hours. After drying, an insulating layer 50 is formed, which is located within the axial projection area of ​​the conductive fiber 10.

[0108] One end of the conductive fiber 10 coated with the thermosensitive coating 40 and the insulating layer 50 is immersed in conductive silver paste for coating and lifting. During the immersion process, the thermosensitive coating 40 is controlled to not be completely covered by the outer electrode layer 30. The outer electrode layer 30 is connected to one end of the detection terminal lead 90 through conductive silver paste, and then placed in an 80°C oven for curing and drying for 1 hour to obtain a uniform outer electrode layer 30.

[0109] A polymer cyclomethylsiloxane and a crosslinking curing agent diphenylcarbamate were mixed at a mass ratio of 30:1 to obtain a viscous liquid. The mixture was stirred for 5 minutes to prepare a polymer membrane solution. After being refrigerated for 1 day, one end of the conductive fiber 10 coated with the outer electrode layer 30 was immersed in the polymer membrane solution, so that the polymer membrane solution completely covered the outer electrode layer 30 and the thermal coating 40 of the conductive fiber 10. The solution was then placed in an 80°C oven for 1 hour to cure, forming a uniform and transparent encapsulation protective layer 20. A flexible wearable thermal fiber was obtained, with the end of the flexible wearable thermal fiber without the thermal coating 40 serving as the electrical signal output end.

[0110] Two connection modules 70 are provided on the surface of the non-conductive bandage 60. The output end and detection end lead-out line 90 of the thermal fiber pass through the non-conductive bandage 60 from the same side. The detection end lead-out line 90 of the thermal fiber is fixed by the connection module 70. The electrical signal output end of the thermal fiber is connected to the electrical signal output end lead-out line 80 through the connection module 70. Finally, the connection module 70 and the non-conductive bandage 60 are fixed by AB glue to obtain a wearable temperature sensor for temperature detection.

[0111] The wearable temperature sensor prepared in Example 2 was subjected to temperature response test, bending resistance test and pressure resistance test. The temperature sensitivity B value of the wearable temperature sensor was 3510K. Under the pressure of 500g weight, the resistance change rate reached 0.3%, and the resistance change rate reached 0.7% in the bending test.

[0112] Example 3

[0113] Example 3 was carried out in accordance with Example 1, except that the mass ratio of the thermosensitive material to the polymer was 20:79.

[0114] The wearable temperature sensor prepared in Example 3 was subjected to temperature response test, bending resistance test and pressure resistance test. It was found that the temperature sensitivity B value of the wearable temperature sensor was 2450K, the resistance change rate in the pressure test was 0.13%, and the resistance change rate in the bending test was 0.4%.

[0115] Example 4

[0116] Example 4 was carried out in accordance with Example 1, except that the mass ratio of the heat-sensitive material to the polymer was 50:49.

[0117] The wearable temperature sensor prepared in Example 4 was subjected to temperature response test, bending resistance test and pressure resistance test. It was found that the temperature sensitivity B value of the wearable temperature sensor was 3856K, the resistance change rate in the pressure test was 0.51%, and the resistance change in the bending test exceeded 1.16%.

[0118] Example 5

[0119] Example 5 was carried out in accordance with Example 1, except that the coating lifting speed was 15 mm / min and the thickness of the thermal coating 40 was 10 μm.

[0120] The wearable temperature sensor prepared in Example 5 was subjected to bending resistance and pressure resistance tests. It was found that the resistance of the thermistor was about 0.3 times that of Example 1. The resistance change rate in the pressure test was 0.25%, and the resistance change rate in the bending test was 0.58%.

[0121] Example 6

[0122] Example 6 was carried out in accordance with Example 1, except that the coating lifting speed was 28 mm / min and the thickness of the thermal coating 40 was 55 μm.

[0123] The wearable temperature sensor prepared in Example 6 was subjected to bending resistance and pressure resistance tests. It was found that the resistance of the thermistor was about 1.7 times that of Example 1. The resistance change rate in the pressure test was 0.18%, and the resistance change rate in the bending test was 0.45%.

[0124] Example 7

[0125] Example 7 was carried out in accordance with Example 1, except that the conductive fiber was a tungsten wire with a diameter of 0.1 mm.

[0126] The wearable temperature sensor prepared in Example 7 was subjected to bending resistance test and pressure resistance test, and it was found that the resistance change rate was 0.43% in the pressure resistance test and 0.95% in the bending resistance test.

[0127] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method of making a flexible wearable heat sensitive fiber, characterized in that, Includes the following steps: One end of a conductive fiber is immersed in a composite ink for coating and lifting, and then cured to form a thermosensitive coating. The end with the thermosensitive coating is the detection end of the conductive fiber. The composite ink is obtained by mixing a thermosensitive material with a polymer solution. The thermosensitive material is nano-nickel oxide. An insulating layer is formed on the surface of the thermosensitive coating, and the insulating layer is located within the axial projection area of ​​the conductive fiber; The detection end of the conductive fiber is immersed in conductive silver paste for coating and lifting, without the conductive silver paste contacting the conductive fiber. After removal, the detection end lead is attached to the conductive silver paste on the surface of the conductive fiber, and then cured to form an external electrode layer. Simultaneously, the detection end lead is electrically connected to the external electrode layer. The detection end of the conductive fiber is immersed in a polysiloxane solution, and then removed and cured to form an encapsulation protective layer.

2. The method for preparing flexible wearable thermosensitive fibers according to claim 1, characterized in that, In the step of immersing one end of the conductive fiber into the composite ink for coating and lifting, the lifting speed is 15mm / min-40mm / min.

3. The method for preparing flexible wearable thermosensitive fibers according to claim 1, characterized in that, The thickness of the thermal coating is 10μm-100μm, and the diameter of the conductive fiber is 0.1mm-0.2mm.

4. The method for preparing flexible wearable thermosensitive fibers according to claim 1, characterized in that, The composite ink also satisfies at least one of the following conditions: (1) The mass ratio of the thermosensitive material to the polymer solution is 20:79.95-50:49.9; (2) The polymer solution comprises a polymer and an organic solvent, wherein the mass ratio of the polymer to the organic solvent is 1:5-1:8, the polymer comprises at least one of polyimide, polyurethane, polyethylene terephthalate or polyvinylidene fluoride, and the organic solvent comprises at least one of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, triethyl phosphate or dimethyl sulfoxide; (3) The composite ink also includes a surfactant, which includes at least one of cetyltrimethylammonium bromide, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyoxyethylene stearate or polyethylene glycol dioleate.

5. The method for preparing flexible wearable thermosensitive fibers according to claim 1 or 2, characterized in that, The conductive fibers are selected from tungsten wire, copper wire, stainless steel wire, carbon fiber, copper-plated nylon, or silver-plated nylon.

6. A flexible wearable thermal fiber prepared by the method of any one of claims 1-5, characterized in that, The device includes conductive fibers and a thermosensitive coating, an external electrode layer, and an encapsulation protective layer sequentially covering the outer surface of any one end of the conductive fibers. The conductive fibers and the external electrode layer do not contact each other. An insulating layer is also provided between the thermosensitive coating and the external electrode layer within the axial projection area of ​​the conductive fibers. The thermosensitive coating is based on a polymer, and the base material includes a thermosensitive material. The flexible wearable thermal fiber also includes a detection end lead wire, which penetrates the encapsulation protective layer and forms an electrical connection with the outer electrode layer.

7. The flexible wearable thermosensitive fiber according to claim 6, characterized in that, The flexible wearable thermosensitive fiber also includes an electrical signal output lead wire, which forms an electrical connection with the other end of the conductive fiber away from the thermosensitive coating.

8. The application of a flexible wearable thermosensitive fiber as described in any one of claims 6-7 in a wearable temperature sensor.

9. A wearable temperature sensor, characterized in that, Includes the flexible wearable thermal fiber as described in any one of claims 6-7 and a non-conductive bandage, wherein the two ends of the flexible wearable thermal fiber penetrate from the same side of the non-conductive bandage and are fixed to the surface of the non-conductive bandage by a connecting module.

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