Ultra-sensitive flexible temperature sensor based on fluff structure and preparation method thereof

Abstract

The invention belongs to the technical field of flexible sensors, and particularly provides an ultra-sensitive flexible temperature sensor based on a fluff structure and a preparation method thereof, which are used for improving the signal response strength and response speed of the temperature sensor. The ultra-sensitive flexible temperature sensor comprises a flexible electronic skin and a villus sensing structure, wherein the villus sensing structure is vertically arranged on the flexible electronic skin; the bionic fluff three-dimensional structure design is adopted, the thermoelectric material is arranged on the bionic fluff structure to form the fluff sensing structure, the temperature of the external environment (airflow) can be rapidly sensed through the slender fluff structure, the sensitivity and precision of the device are greatly improved, meanwhile, the structural complexity is reduced, the size of the sensor is effectively reduced, and the cost is reduced. Therefore, the method is suitable for more application scenes, such as machine perception and man-machine interaction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flexible sensors, and particularly provides an ultra-sensitive flexible temperature sensor based on a villus structure and a preparation method thereof. BACKGROUND

[0002] Temperature is an important detection parameter of production activities and working processes, so the flexible temperature sensing technology plays an increasingly important role in the fields of wearable devices, electronic skin, medical detection, industrial production, etc. The measurement value of a temperature sensor is often affected by a temperature gradient, but when measuring the temperature of an environment (air flow), the temperature of the environment and the temperature of the device are not much different. For the planar two-dimensional structure of a traditional temperature sensor, it is difficult for the temperature sensor to form a large temperature gradient when measuring air flow, so that it is difficult to adapt to the rapid change of a small temperature, and it also leads to poor time response characteristics of the temperature sensor to the temperature of the air flow, thereby generating measurement errors. However, there is a great demand for collecting environmental temperature information in the fields of human-computer interaction, bionic robots, wearable devices, etc. Therefore, it is urgent to develop a flexible temperature sensor with high sensitivity, high precision and high integration. SUMMARY

[0003] The application aims to provide an ultra-sensitive flexible temperature sensor based on a villus structure and a preparation method thereof, so as to improve the signal response strength and response speed of the temperature sensor. The application adopts a bionic villus three-dimensional structure design, effectively increases the temperature difference between the two ends of the thermoelectric material, and enhances the heat exchange contact area between the villus and the environment, thereby significantly improving the signal response strength and response speed. Finally, a flexible temperature sensor with high sensitivity, high precision and high integration is obtained.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0005] An ultra-sensitive flexible temperature sensor based on a villus structure, characterized in that it comprises a flexible electronic skin and a villus sensing structure; wherein the flexible electronic skin comprises a substrate layer 101, a first electrode layer 102, a first insulation layer 103, a second electrode layer 104 and a first protective layer 105, and the villus sensing structure comprises a villus 201, a thermoelectric material layer 202, a second insulation layer 203, a third electrode layer 204 and a second protective layer 205.

[0006] The villi are arranged perpendicular to the plane of the base layer, the bottom end of the villi is fixedly arranged in the base layer, and the side surface of the villi covers the thermoelectric material layer; the first electrode layer is arranged on the base layer and is electrically connected to the bottom end of the thermoelectric material layer; the first isolation layer is arranged on the first electrode layer, and the second isolation layer is coated on the side surface of the thermoelectric material layer; the second electrode layer is arranged on the first isolation layer, and the third electrode layer is coated on the side surface of the second isolation layer and the top of the villi and the thermoelectric material layer, so that the top of the thermoelectric material layer is electrically connected to the second electrode layer through the third electrode layer, and the first isolation layer and the second isolation layer jointly realize the electrical isolation of the first electrode layer and the second electrode layer; the first protective layer is arranged on the second electrode layer, the second protective layer is coated on the outer surface of the third electrode layer, and the first protective layer and the second protective layer jointly form a protective layer of the ultra-sensitive flexible temperature sensor.

[0007] Furthermore, the fluff is made of insulating fibers such as aramid fibers, nylon fibers or glass fibers.

[0008] Furthermore, the length of the villi ranges from 0.1 mm to 50 mm, and the diameter ranges from 10 μm to 2000 μm.

[0009] Furthermore, the thermoelectric material layer is made of one or more inorganic or organic materials with thermoelectric properties, such as silver selenide, bismuth telluride, carbon material, and pedot.

[0010] Furthermore, the base layer, the first protective layer, and the second protective layer are made of one of SEBS and PDMS, and the three can be made of the same material or different materials.

[0011] Furthermore, the first electrode layer, the second electrode layer and the third electrode layer are made of Ag thin film.

[0012] At the same time, the present invention provides a method for preparing the ultra-sensitive flexible temperature sensor based on the villi structure, which is characterized by comprising the following steps:

[0013] The polymer solution is solidified to form the base layer of the flexible electronic skin, and the hairs are fixed vertically in the base layer;

[0014] Depositing a conductive film on the surface of the base layer to form a first electrode layer, and coating a polymer on the surface of the first electrode layer to form a first insulating layer;

[0015] Depositing thermoelectric material on the surface of the hair side to form a thermoelectric material layer, and coating the surface of the thermoelectric material layer with polymer to form a second insulating layer;

[0016] Cutting off the tip of the villi to expose the top of the thermoelectric material layer;

[0017] Conductive films are deposited on the surfaces of the first insulating layer and the second insulating layer to form the second electrode layer and the third electrode layer respectively, and polymers are coated on the surfaces of the second electrode layer and the third electrode layer to form the first protective layer and the second protective layer respectively.

[0018] Based on the above technical solution, the beneficial effects of the present invention are:

[0019] When sensing changes in ambient (airflow) temperature, existing bulk thermoelectric materials or sheet thermoelectric films cannot form a large temperature difference due to their own structural reasons, and are large in size, so they can only be improved through external measures. On this basis, the present invention provides an ultra-sensitive flexible temperature sensor based on a fuzz structure, which creatively arranges thermoelectric materials on a bionic fuzz structure. The slender fuzz structure alone can quickly sense the external environment (airflow) temperature, greatly improving the sensitivity and accuracy of the device, while reducing structural complexity and effectively reducing the size of the sensor, making it suitable for more application scenarios (such as machine perception and human-computer interaction). BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the ultra-sensitive flexible temperature sensor based on the fuzz structure in the present invention; wherein, 101 is the base layer, 102 is the first electrode layer, 103 is the first insulating layer, 104 is the second electrode layer, and 105 is the first protective layer; 201 is the fuzz, 202 is the thermoelectric material layer, 203 is the second insulating layer, 204 is the third electrode layer, and 205 is the second protective layer.

[0021] Figure 2 This is a flow chart of the preparation method of the ultra-sensitive flexible temperature sensor based on the villi structure in the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0023] Example 1

[0024] This embodiment provides an ultra-sensitive flexible temperature sensor based on a fuzz structure, the structure of which is as follows: Figure 1 As shown, it includes: flexible electronic skin and a hair sensing structure; this embodiment adopts a bionic hair structure, and the hair sensing structure is vertically set on the flexible electronic skin. When the air flow flows through the surface of the hair sensing structure, the hairs at different heights have different temperatures, and the carriers in the thermoelectric material move in a directional manner to generate an electric potential difference. Finally, the two electrode layers of the flexible electronic skin show a voltage difference, and a voltage signal is output, thereby realizing sensitive detection of the ambient temperature.

[0025] Specifically, the flexible electronic skin includes: a base layer 101, a first electrode layer 102, a first insulating layer 103, a second electrode layer 104 and a first protective layer 105; the hair sensing structure includes: hair 201, a thermoelectric material layer 202, a second insulating layer 203, a third electrode layer 204 and a second protective layer 205;

[0026] The villi are arranged perpendicular to the plane of the base layer, the bottom end of the villi is fixedly arranged in the base layer, and the side surface of the villi covers the thermoelectric material layer; the first electrode layer is arranged on the base layer and is electrically connected to the bottom end of the thermoelectric material layer; the first isolation layer is arranged on the first electrode layer, and the second isolation layer is coated on the side surface of the thermoelectric material layer; the second electrode layer is arranged on the first isolation layer, and the third electrode layer is coated on the side surface of the second isolation layer and the top of the villi and the thermoelectric material layer, so that the top of the thermoelectric material layer is electrically connected to the second electrode layer through the third electrode layer, and the first isolation layer and the second isolation layer jointly realize the electrical isolation of the first electrode layer and the second electrode layer; the first protective layer is arranged on the second electrode layer, the second protective layer is coated on the outer surface of the third electrode layer, and the first protective layer and the second protective layer jointly form a protective layer of the ultra-sensitive flexible temperature sensor.

[0027] At the same time, this embodiment also provides a method for preparing the ultra-sensitive flexible temperature sensor based on the villi structure, the process of which is as follows: Figure 2 As shown, the specific steps include:

[0028] (1) preparing a SEBS solution according to a mass ratio of styrene-ethylene-butylene-styrene block copolymer (SEBS) to n-hexane of 1:15 to 1:20;

[0029] (2) Take a 5 mm glass fiber as the fluff 201 and fix it vertically in the SEBS solution;

[0030] (3) Drying the SEBS solution to form a base layer 101, and firmly fixing the bottom ends of the hairs 201 vertically to the surface of the base layer 101;

[0031] (4) The device obtained in step (3) is subjected to chemical silver plating to deposit a silver film on the substrate layer and the surface of the fuzz, and the silver film on the substrate layer forms the first electrode layer 102;

[0032] (5) evenly scraping the aqueous PU solution onto the surface of the first electrode layer 102 to a thickness of 100 μm, and drying to obtain a PU film;

[0033] (6) Evenly apply the SEBS solution on the PU film to a thickness of 100 μm, and form a first insulating layer 103 after drying;

[0034] (8) The silver film on the hair 201 is completely immersed in a sodium selenide solution for 60 minutes to obtain a layer of Ag2Se film, forming a thermoelectric material layer 202;

[0035] (9) Evenly apply the SEBS solution on the thermoelectric material layer 202 to a thickness of 100 μm, and obtain the second insulating layer 203 after drying;

[0036] (10) Cutting off a portion of the tip of the villi 201 in order to remove the second insulating layer 203 at the tip and expose the top of the thermoelectric material layer 202;

[0037] (11) chemically silver-plating the surface of the device obtained in step (10) to form a second electrode layer 104 and a third electrode layer 204;

[0038] (12) evenly scraping the aqueous PU solution onto the surface of the device obtained in step (11) to a thickness of 100 μm, and drying to obtain a PU film;

[0039] (13) The SEBS solution is evenly coated on the PU film with a coating thickness of 100 μm. After drying, the first protective layer 105 and the second protective layer 205 are obtained.

[0040] Example 2

[0041] This embodiment provides an ultra-sensitive flexible temperature sensor based on a fuzz structure. Its structure is the same as that of Example 1, except that the thermoelectric material layer uses pedot. The ultra-sensitive flexible temperature sensor is prepared by the following steps:

[0042] (1) preparing a SEBS solution according to a mass ratio of styrene-ethylene-butylene-styrene block copolymer (SEBS) to n-hexane of 1:15 to 1:20;

[0043] (2) Take a 5 mm glass fiber as the fluff 201 and fix it vertically in the SEBS solution;

[0044] (3) Drying the SEBS solution to form a base layer 101, and firmly fixing the bottom ends of the hairs 201 vertically to the surface of the base layer 101;

[0045] (4) coating the surface of the hair 201 with a pedot solution and drying it to form a thermoelectric material layer 202;

[0046] (5) forming a first electrode layer 102 by chemically plating silver on the surface of the substrate layer 101 to obtain a silver thin film;

[0047] (6) evenly scraping the aqueous PU solution onto the surface of the first electrode layer 102 and the thermoelectric material layer 202 to a thickness of 100 μm, and then drying to obtain a PU film;

[0048] (7) The SEBS solution is uniformly scraped on the PU film, with a scraping thickness of 100 μm, and after drying, the first insulation layer 103 and the second insulation layer 203 are obtained;

[0049] (8) A part of the tip of the villus 201 structure is cut off, so as to remove the insulation layer 203 of the tip and expose the top part of the thermoelectric material layer 202;

[0050] (9) The device surface obtained in step (8) is chemically plated with silver to form the second electrode layer 104 and the third electrode layer 204;

[0051] (10) The aqueous PU solution is uniformly scraped on the device surface obtained in step (9), with a scraping thickness of 100 μm, and after drying, the PU film is obtained;

[0052] (11) The SEBS solution is uniformly scraped on the PU film, with a scraping thickness of 100 μm, and after drying, the first protection layer 105 and the second protection layer 205 are obtained.

[0053] In summary, the present application provides a flexible temperature sensor, and the villus sensing structure has the characteristics of high sensitivity, high precision and low delay. The overall device structure is simple, integrally formed, and convenient for integrated application, and can meet various application scenarios, and has great application potential.

[0054] The above is only a specific embodiment of the present application, and any feature disclosed in the specification can be replaced by other equivalent or similar purpose alternative features, unless specifically stated. All features disclosed, or steps in all methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. An ultra-sensitive flexible temperature sensor based on a fuzz structure, characterized in that: include: Flexible electronic skin and a hair sensing structure; wherein the flexible electronic skin comprises: a base layer (101), a first electrode layer (102), a first insulating layer (103), a second electrode layer (104) and a first protective layer (105); and the hair sensing structure comprises: hair (201), a thermoelectric material layer (202), a second insulating layer (203), a third electrode layer (204) and a second protective layer (205); The villi are arranged perpendicular to the plane of the base layer, the bottom end of the villi is fixedly arranged in the base layer, and the side surface of the villi covers the thermoelectric material layer; the first electrode layer is arranged on the base layer and is electrically connected to the bottom end of the thermoelectric material layer; the first isolation layer is arranged on the first electrode layer, and the second isolation layer is coated on the side surface of the thermoelectric material layer; the second electrode layer is arranged on the first isolation layer, and the third electrode layer is coated on the side surface of the second isolation layer and the top of the villi and the thermoelectric material layer, so that the top of the thermoelectric material layer is electrically connected to the second electrode layer through the third electrode layer, and the first isolation layer and the second isolation layer jointly realize the electrical isolation of the first electrode layer and the second electrode layer; the first protective layer is arranged on the second electrode layer, the second protective layer is coated on the outer surface of the third electrode layer, and the first protective layer and the second protective layer jointly form a protective layer of the ultra-sensitive flexible temperature sensor.

2. The ultra-sensitive flexible temperature sensor based on the fuzz structure according to claim 1, characterized in that: The fluff is made of aramid fiber, nylon fiber or glass fiber.

3. The ultra-sensitive flexible temperature sensor based on the fuzz structure according to claim 1, characterized in that: The length of the villi ranges from 0.1 mm to 50 mm, and the diameter ranges from 10 μm to 2000 μm.

4. The ultra-sensitive flexible temperature sensor based on the fuzz structure according to claim 1, characterized in that: The thermoelectric material layer is made of one or more of silver selenide, bismuth telluride, carbon material, and pedot.

5. The ultra-sensitive flexible temperature sensor based on the fuzz structure according to claim 1, characterized in that: The base layer, the first protective layer and the second protective layer are respectively made of SEBS or PDMS.

6. The ultra-sensitive flexible temperature sensor based on the fuzz structure according to claim 1, characterized in that: The first electrode layer, the second electrode layer and the third electrode layer are made of Ag thin films.

7. The method for preparing the ultra-sensitive flexible temperature sensor based on the villi structure according to claim 1, characterized in that: The following steps are involved: The polymer solution is solidified to form the base layer of the flexible electronic skin, and the hairs are fixed vertically in the base layer; Depositing a conductive film on the surface of the base layer to form a first electrode layer, and coating a polymer on the surface of the first electrode layer to form a first insulating layer; Depositing thermoelectric material on the surface of the hair side to form a thermoelectric material layer, and coating the surface of the thermoelectric material layer with polymer to form a second insulating layer; Cutting off the tip of the villi to expose the top of the thermoelectric material layer; Conductive films are deposited on the surfaces of the first insulating layer and the second insulating layer to form the second electrode layer and the third electrode layer respectively, and polymers are coated on the surfaces of the second electrode layer and the third electrode layer to form the first protective layer and the second protective layer respectively.

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