WO2019010670A1

WO2019010670A1 - Flexible stretchable strain sensor and preparation method therefor

Info

Publication number: WO2019010670A1
Application number: PCT/CN2017/092799
Authority: WO
Inventors: 李晖; 陈静; 高钦武; 王磊
Original assignee: 中国科学院深圳先进技术研究院
Priority date: 2017-07-13
Filing date: 2017-07-13
Publication date: 2019-01-17

Abstract

A flexible stretchable strain sensor, comprising a flexible substrate (1), wherein a flexible microchannel (10) is arranged in the flexible substrate (1), a liquid conductor or a semi-liquid conductor (3) is arranged in the microchannel (10), and electrodes (2) are arranged at both ends of the microchannel. A wearable device having the flexible stretchable strain sensor. A preparation method for the flexible stretchable strain sensor, comprising the following steps: preparing the flexible substrate (1) having the microchannel (10); and injecting the liquid conductor or the semi-liquid conductor (3) into the microchannel (10), and inserting the electrodes (2) at both ends of the microchannel. The flexible stretchable strain sensor provided by the present invention has the geometrical characteristics of high flexibility, stretchability and being thin, may be directly integrated with any flexible actuator, has high sensitivity and strong anti-interference capability, and may still work normally when the strain reaches 300%.

Description

Flexible tensile strain sensor and preparation method thereof

[0001] The present invention belongs to the technical field of sensor fabrication and packaging, and in particular, to a flexible tensile strain sensor and a preparation method thereof.

Background technique

[0002] As the application requirements of information generation become higher and higher, the expected values and idealization requirements of various performance parameters such as the range, accuracy, and stability of the measured information are gradually increased. The sensor system applied to wearable devices has gradually shown its limitations in some applications, including the current lack of flexibility of the sensor, and the inability to achieve true stretchability. Once the strain or bending angle is too large, the structure of the entire sensor will be obtained. Destruction and failure; low sensitivity, easy to be disturbed by human physiological signal noise, resulting in fuzzy and incomplete signal acquisition.

[0003] Since the launch of the Google Incidents Conference in 2012, the launch of "Google Glass" has greatly stimulated the market's interest in wearable devices. The emergence of a wide variety of wearable devices in just a few years has brought us a variety of conveniences. For example, smart watch body temperature pulse detection and step counting function, high-sensitivity electronic skin transmits skin tactile information to the brain, and uses three-dimensional microelectrodes to realize cerebral cortex control prostheses. As one of the core components, the sensor will affect the functional design and future development of the wearable device. In the actual use of wearable devices, many times require sensors to be transparent, flexible, stretchable, free to bend or even fold, high sensitivity, etc., especially the working environment is directly on the complex irregular skin surface of the human body with large deformation. For example, deformation detection of joints, etc.

[0004] Flexible sensors in the prior art are mainly prepared in the following manner.

[0005] 1. Using a contact printing method to fabricate a field effect transistor by using a semiconductor nanowire attached to a flexible material, the source electrode is grounded through a pressure sensitive rubber, and external pressure causes a change in conductivity of the varistor, thereby changing the properties of the transistor. A change in the detected output signal is obtained to obtain a corresponding load.

[0006] 2. Using a carbon nanotube sprayed on a PDMS sheet to form a rectangular conductive array to form a transparent sensor array with good transparency, the twisted carbon nanotubes and the mesh structure formed thereby enable macroscopic wires to follow the elastic material. Stretching and stretching the same to ensure conductivity. [0007] 3. With the conductive textile, it is made into a flexible electrode embedded in the PDMS, and the upper electrode and the bottom electrode respectively generate capacitances, and the multi-dimensional force can be detected by measuring the relative change of the four capacitance values.

[0008] 4. Porous nylon, which is similar to skin mechanical properties, is used as a substrate to electrochemically deposit polypyrrole as a conductive dopant in the matrix. When the load is loaded, the conductivity of the sensor is increased to measure the external load.

[0009] 5. Using a highly elastic and durable telescopic spiral electrode, PDMS is used as the main structural material. Create a highly distorted array of tactile sensors. It can accommodate complex work surfaces without damaging the sensor array and the sensing array on the metal interconnect.

[0010] Although the strain sensor described above has a certain flexibility, it does not achieve true stretchability, lacks skin-like flexibility, and cannot fully realize the external load under the condition of covering a three-dimensional complex static/dynamic surface. Measurement. When the strain or bending angle is large, the entire system will destroy the failure. Compared with the surface of human skin, the same kind of rigidity still shows a certain degree of discomfort, which makes the human body feel uncomfortable and difficult to integrate, which greatly limits the stability, accuracy and accuracy of the measurement. In addition, human physiological signals are easily interfered by external factors such as perspiration, muscle contraction, etc., and users cannot eliminate these influencing factors, resulting in ambiguity and incompleteness of data collection, and poor reliability.

technical problem

[0011] The object of the present invention is to overcome the above deficiencies of the prior art, and to provide a flexible tensile strain sensor and a preparation method thereof, the stability, accuracy, accuracy and reliability of the flexible tensile strain sensor.

Problem solution

Technical solution

[0012] The technical solution of the present invention is: a flexible tensile strain sensor, comprising a flexible substrate, the flexible substrate has a flexible microchannel, the microchannel is provided with a liquid conductor or a semi-liquid conductor, Electrodes are provided at both ends of the microchannel.

[0013] Optionally, the flexible substrate is made of a degradable polyester material or a silicone rubber material.

[0014] Optionally, a liquid conductor eutectic gallium indium is disposed in the microchannel.

[0015] Optionally, the microchannels are strip-shaped, line-shaped, serpentine, circular or curved; or/and, the microchannels are provided with one or at least two. [0016] The present invention also provides a wearable device having the above-described flexible stretch strain sensor.

[0017] The present invention also provides a method for preparing a flexible tensile strain sensor, comprising the following steps:

[0018] preparing a flexible substrate having microchannels; injecting a liquid conductor or a semi-liquid conductor into the microchannel, and inserting electrodes at both ends of the microchannel.

[0019] Optionally, preparing the flexible substrate comprises the following steps:

[0020] preparing a microchannel mold and a flexible material solution, mixing the flexible material solution to remove air bubbles;

[0021] adding the flexible material solution after mixing and removing bubbles into the microchannel mold to form a flexible matrix body

[0022] dropping a flexible material solution after mixing and removing the bubbles on the substrate, and forming a flexible material solution into a film of a flexible material;

[0023] pressing the flexible substrate body against the incompletely cured film of flexible material such that the flexible substrate body and the flexible material film form a flexible substrate having microchannels.

[0024] Optionally, injecting the liquid conductor or the semi-liquid conductor into the microchannel comprises the following steps:

[0025] two syringes are inserted into both ends of the microchannel, one of the syringes has a liquid conductor; the other syringe draws air in the microchannel, and a syringe having a liquid conductor injects a liquid conductor into the microchannel , fill the liquid conductor with the microchannel and pull out the syringe.

Optionally, inserting the electrodes at both ends of the microchannel includes the following steps:

[0027] Two electrodes are respectively inserted at both ends of the microchannel, and the microchannel is sealed with a flexible material solution.

[0028] Optionally, mixing and removing the bubbles of the flexible material solution comprises the steps of:

[0029] The Ecoflex series silicone rubber solution is placed in a container of a centrifugal mixer, the rotation speed of the centrifugal mixer is 300-400 rpm, and after maintaining the turn for 10-15 s, the rotation speed of the centrifugal mixer is increased to 1400- 1600 rp m, maintaining a turn of 25-30 s, obtaining a mixed silicone rubber solution;

[0030] The mixed silicone rubber solution is placed in a vacuum suction device, and the vacuum pump of the vacuum suction device is activated to obtain a silicone rubber solution after removing bubbles;

[0031] Forming the flexible substrate body comprises the steps of:

[0032] spraying at least one release agent film on the surface of the microchannel mold, and then using a pipette to fill the microchannel mold with a silicone rubber solution after removing bubbles; [0033] The microchannel mold is moved to an oven, baked at 80 degrees Celsius for 45-60min, after demolding to obtain a flexible matrix body;

[0034] dripping the silicone rubber solution after removing the bubbles on the substrate, and rotating into a homogenizing machine to form a layer of silicone rubber film, the speed of the homogenizing machine is set to 350-400 rpm, and the uniformity of the glue is 25-30 seconds;

[0035] After the silicone rubber film is in a semi-solidified state, the flexible substrate body after demolding is pressed on the silicone rubber film, and the flexible substrate body and the silicone rubber film are sealed and sealed, and left at room temperature for 45-60 minutes to obtain A flexible substrate with microchannels.

Advantageous effects of the invention

Beneficial effect

[0036] A flexible tensile strain sensor and a preparation method thereof are provided by the present invention, and the strain sensor is made of a highly flexible Ecoflex series material as a basic material. Pour into an internal microchannel or microchannel array by microlithography previously prepared by photolithography, followed by spin coating a film of the same material to seal the entire microchannel. The liquid conductor eutectic gallium indium is injected to fill the entire channel. Finally, the electrode is resealed at both ends of the microchannel to complete the preparation. After the sensor is operated, the resistance of the microchannel length and cross section is changed due to the external load. A constant current source is applied across the electrodes. The resistance signal is changed into a voltage signal that is convenient for measurement, and the corresponding strain value is obtained by analyzing the voltage signal. The flexible sensor can still work normally after the strain reaches 300%, and it can work with almost any complicated three-dimensional surface.

DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings to be used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some implementations of the present invention. For example, other drawings may be obtained from those of ordinary skill in the art in light of the inventive work.

1 is a schematic plan view of a flexible tensile strain sensor according to an embodiment of the present invention;

2 is a schematic plan view showing a microchannel having a serpentine shape in a flexible tensile strain sensor according to an embodiment of the present invention;

3 is a method for preparing a flexible and stretchable strain sensor according to an embodiment of the present invention. a schematic plan view of the glue solution;

4 is a schematic plan view showing a mixture of a silicone rubber solution in a method for preparing a flexible tensile strain sensor according to an embodiment of the present invention;

5 is a schematic plan view of a silicone rubber solution in which a bubble is removed in a method for preparing a flexible tensile strain sensor according to an embodiment of the present invention;

6 is a schematic plan view of a method for preparing a flexible tensile strain sensor according to an embodiment of the present invention, in which a microchannel mold is filled with a silicone rubber solution;

7 is a schematic plan view showing a method for preparing a flexible tensile strain sensor according to an embodiment of the present invention, after baking a silicone rubber solution on a microchannel mold;

8 is a schematic plan view of a method for preparing a flexible tensile strain sensor according to an embodiment of the present invention, in which a silicone rubber solution is dropped onto a substrate;

9 is a schematic plan view showing a method of manufacturing a flexible tensile strain sensor according to an embodiment of the present invention, in which a flexible substrate body and a film are pressed together;

10 is a schematic plan view of a flexible tensile strain sensor obtained in a method for preparing a flexible tensile strain sensor according to an embodiment of the present invention.

Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0049] It is to be noted that when an element is referred to as being "fixed" or "in" another element, it can be directly on the other element or the same. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or the same element.

[0050] It should also be noted that the left, right, upper, lower, and the like orientations in the embodiments of the present invention are only relative concepts or reference to the normal use state of the product, and should not be considered as having Restrictive.

As shown in FIG. 1 , a flexible stretchable strain sensor provided by an embodiment of the present invention includes a flexible substrate 1 which can be made of a silicone rubber material (for example, Ecoflex series) or the like. The flexible substrate 1 has a flexible microchannel therein, and the length and cross section of the flexible microchannel can be changed by an external force, and The microchannel 10 is a closed cavity in which a semi-liquid conductor or a liquid conductor 3 is disposed, and the semi-liquid conductor or liquid conductor 3 can fill the microchannel 10. The two ends of the microchannel 10 are provided with an electrode 2, and the end of the electric plate is in contact with the semi-liquid conductor or the liquid conductor 3 in the microchannel 10. After the sensor is operated, the length of the microchannel 10 is caused by the external load. And the cross section changes to change the electrical resistance of the semi-liquid conductor or the liquid conductor 3. A constant current source is applied to the electrodes 2 at both ends. The resistance signal is changed into a voltage signal for convenient measurement, and the corresponding strain value is obtained by analyzing the voltage signal. The sensor mainly collects the liquid conductor or the semi-liquid conductor resistance change signal in the sealed microchannel 10 during operation, and has high flexibility. The stretchability and thin geometry make it easy to integrate directly with any flexible actuator. It has high sensitivity and strong anti-interference ability. The flexible sensor can work normally after the strain reaches 300%, especially suitable for wearable. The field of equipment is especially large deformation, and the stability, accuracy, accuracy and reliability are high.

[0052] Alternatively, the flexible tensile strain sensor may have a thickness of less than 1 mm, that is, the flexible substrate 1 may have a thickness of less than 1 mm, which is well suited for use in smart wearable devices.

[0053] Optionally, the flexible substrate 1 may be made of a degradable polyester material or a silicone rubber material. In this embodiment, the flexible substrate 1 is made of a silicone rubber material of the Ecoflex series as a basic material. In specific applications, the German BASF may be used. The company's aliphatic aromatic random copolyester (Ecoflex), its monomers can be: adipic acid, terephthalic acid, 1,4-butanediol. Degradable materials are generally considered to be plastics that can be decomposed into low molecular weight by means of solar radiation or microorganisms in the soil. In addition to being degradable, they should also have properties that are easy to process and meet the requirements of use. Completely biodegradable plastics are chemically synthesized. They are easily degraded by the use of aliphatic polyesters, polyvinyl alcohol (PVA) and polyethylene glycol. The biodegradable plastics are studied by utilizing the biodegradable properties of these polymers, and the research on aliphatic polyesters is outstanding. Among the many aliphatic polyesters, polycaprolactone (PCL) is widely used. It is a thermoplastic crystalline polyester that can be hydrolyzed into small molecules by lipase and then further assimilated by microorganisms. For surgical products, adhesive films, release agents and other products. Aliphatic polyester and nylon for amine lipid exchange reaction, synthesis of polyacrylate copolymer (CPAE), synthesis of natural polymers in plants and animals, plant cellulose, starch, etc., chitosan, poly in animals Glucosamine, animal glue, and algae from marine life can produce valuable biodegradable materials. Biodegradable polyester is a new type of polymeric material that can be synthesized by fermentation, chemical methods and enzymatic catalysis.

[0054] Optionally, a liquid conductor eutectic gallium indium is disposed in the microchannel 10 as a liquid conductor, and of course, To set up other liquid metal conductors. The electrode 2 may be inserted from both ends of the flexible substrate 1 in the longitudinal direction or both ends of the microchannel 10 to the front end to be in contact with the semi-liquid conductor or the liquid conductor 3 in the microchannel 10. The electrode 2 and the flexible substrate 1 can be sealed by a sealing material to further improve the reliability. The sealing material may be a silicone rubber solution material (Ecoflex).

[0055] In a specific application, the microchannel 10 may be in the form of a strip, a line, or a serpentine. As shown in FIG. 2, the serpentine microchannel 10 of the flexible tensile strain sensor 100 has a reciprocating shape. It is more deformable and can be used on the surface of human skin at a relatively large area. The accuracy and stability of sensing can be further improved. Of course, the microchannel 10 can also have other structural shapes, such as a circular shape, an arc shape, a tapered shape or a profile, etc., all of which fall within the scope of the present invention.

[0056] Optionally, the microchannel may be provided with one or at least two, the microchannel may be one or more, and at least two microchannels may form a microchannel array, and the microchannel in the microchannel array It may be in the form of a rectangular array or a circular array or the like.

[0057] In the tensile test of the flexible tensile strain sensor, the sensitivity is high, and the acquired signal exhibits good linearity and repeatability, and has high stability, accuracy, accuracy, and reliability. The strain reaches 300% and still works normally. It can adhere well to complex three-dimensional dynamic and static surfaces, such as large deformed human joints (elbow joints, knee joints), with good affinity with the skin, and almost normal for people to work. did not affect. It is the ideal flexible sensor for wearing equipment.

[0058] The present invention also provides a wearable device having the above-described flexible stretch strain sensor. Wearable devices can be smart watches, smart bracelets, smart glasses, smart clothing, virtual reality helmets, and more. Through the application of a flexible tensile strain sensor, the flexible tensile strain sensor exhibits a thickness of less than 1 mm and exhibits very good flexibility. The tensile strain reaches 300% and still works properly, which is comparable to human skin. Biocompatible Ecoflex materials can be used as the basic material, and there is almost no discomfort in the integration into wearable devices. Moreover, the sensor collects the sealed microchannel 10 resistance signal, which eliminates the interference of external noise on the signal, and the collected data is more accurate. The microchannel 10, which is characterized by photolithography, greatly increases the sensitivity of the sensor. Of course, the flexible tensile strain sensor provided by the embodiment of the present invention can also be applied to other devices, and is also within the protection range of the present invention.

[0059] Embodiments of the present invention also provide a method for preparing a flexible tensile strain sensor, as shown in FIGS. 3 to 10 Show, including the following steps:

[0060] A flexible substrate 1 having a sealed microchannel 10 is prepared; a semi-liquid conductor or a liquid conductor 3 is injected into the microchannel 10, and an electrode 2 is inserted at both ends of the microchannel 10. The semi-liquid conductor or liquid conductor 3 can fill the microchannel 10, and the end of the electrode 2 is in contact with the semi-liquid conductor or the liquid conductor 3.

[0061] Optionally, preparing the flexible substrate 1 comprises the following steps:

[0062] preparing a microchannel mold 41 and a flexible material solution, and mixing the flexible material solution to remove air bubbles;

[0063] adding the flexible material solution after mixing and removing bubbles into the microchannel mold 41 to form a flexible matrix body 11;

[0064] a flexible material solution mixed with and removed from the bubble is dropped onto the substrate 42, and the flexible material solution is formed into a film of a flexible material (silicone rubber film 12);

Pressing the flexible substrate body 11 against the incompletely cured film of the flexible material (silicone rubber film 12) to form the flexible substrate body 11 and the flexible material film (silicone rubber film 12) with microchannels 1

0 flexible substrate 1;

[0066] Optionally, injecting the semi-liquid conductor or the liquid conductor 3 into the microchannel 10 includes the following steps:

[0067] Two syringes may be inserted into both ends of the microchannel 10, one of which has a liquid conductor 3 therein; another syringe draws air in the microchannel 10, and a syringe having a liquid conductor 3 is directed to the micro The liquid conductor 3 is injected into the channel 10, the liquid conductor 3 is filled with the microchannel 10, and the syringe is pulled out.

[0068] Optionally, inserting the electrode 2 at both ends of the microchannel 10 includes the following steps:

[0069] Two electrodes 2 are respectively inserted into both ends of the microchannel 10, and the microchannel 10 is sealed with a flexible material solution.

[0070] Optionally, mixing and removing the bubbles of the flexible material solution comprises the steps of:

[0071] The Ecoflex series silicone rubber solution can be placed in a container of a centrifugal mixer, the rotation speed of the centrifugal mixer is 300-400 rpm, and the rotation speed of the centrifugal mixer is increased to 1400 after maintaining the daytime for 10-15 s. -1

600 rpm, maintaining the daytime for 25-30 s, to obtain a mixed silicone rubber solution;

[0072] Putting the mixed silicone rubber solution into a vacuum suction device, and opening the vacuum pump of the vacuum suction device

The silicone rubber solution after the bubble removal is obtained; it is understood that the flexible material solution is not limited to the silicone rubber solution.

[0073] Forming the flexible substrate body 11 includes the following steps: [0074] spraying at least one release agent film on the surface of the microchannel mold 41, and then using a pipette to fill the microchannel mold 41 with a silicone rubber solution after removing bubbles;

[0075] The microchannel mold 41 is moved to an oven, baked at 80 degrees Celsius for 45-60 minutes, after demolding to obtain a flexible substrate body 11;

[0076] The silicone rubber solution after removing the bubbles is dropped on the substrate 42 and rotated into a homogenizer to form a silicone rubber film 12, and the speed of the homogenizer is set to 350-400 rpm, and the uniformity is 25-30. second;

[0077] After the silicone rubber film 12 is in a semi-solidified state, the demolded flexible substrate body 11 is pressed against the silicone rubber film 12, and the flexible substrate body 11 and the silicone rubber film 12 are sealed and sealed, and left at room temperature. 45-60 min, a flexible substrate 1 with microchannels 10 is obtained.

[0078] In a specific application, the following processes may be referred to:

[0079] A microchannel mold 41 (material is SU-8 photoresist) prepared by photolithography; liquid metal conductor eutectic gallium indium ((EGaln); highly flexible Ecoflex series material; ease release 200 demoulding Specifically, the following steps are included:

[0080] First step: As shown in FIG. 3 and FIG. 4, equal amounts of Ecoflex 1 A and 1B are respectively placed in a container of the centrifugal mixer to ensure that the two silicone rubbers are sufficiently uniformly mixed. The centrifugal mixer rotates at 300-400 rpm for 10-15 s, then increases to 1400-1600 rpm for 25-30 s.

[0081] Second step: As shown in FIG. 4 and FIG. 5, the silicone rubber solution in the first step is placed in a vacuum suction device, and the vacuum pump is driven until all the bubbles in the solution are removed.

[0082] The third step: as shown in FIG. 6, the surface of the microchannel mold 41 is sprayed with a release agent film 12, and then the liquid rubber is used to fill the mold with the silicone rubber solution obtained in the second step, as shown in the figure. 6 is shown.

[0083] The fourth step: The filled microchannel mold 41 is moved to the oven and baked at 80 degrees Celsius for 45-60 m in, as shown in Fig. 7, to obtain a flexible substrate main body 11.

[0084] Step 5: Drip an appropriate amount of the silicone rubber solution obtained in the second step onto the substrate 42 and rotate it into a homogenizer to form a film 12, and the speed of the homogenizer is set to 350-400 rpm. The daytime is 25-30s, as shown in Figure 8.

[0085] Step 6: The film 12 formed in the fifth step is in a semi-solidified state, and the demolded microchannel silicone rubber is removed.

(Flexible substrate body 11) Gently press on the film 12, and the adhesive is sealed and left to stand at room temperature for 45-60 minutes, as shown in Fig. 9. [0086] Step 7: Two micro-injectors are inserted into the microchannels 10, one syringe is used to pump the air inside the microchannels 10, and the liquid conductor-EGaln is drained, and a syringe is used to continuously inject the liquid conductors (EGaln) to In the microchannel 10. When the liquid conductor (EGaln) fills the entire microchannel 10吋, insert the electrode 2, take a small amount of silicone rubber solution (obtained in the second step) to seal the port, so that a flexible stretchable electronic strain sensor can be obtained, as shown in Fig. 10. Shown. The method is simple to prepare, can realize mass production at one time, and improves daytime and cost effectiveness. It is especially suitable for the field of wearable devices, especially large deformations.

[0087] A flexible tensile strain sensor and a preparation method thereof are provided by an embodiment of the present invention, and the strain sensor is made of a highly flexible Ecoflex series material. The inner microchannel 10 or microchannel 10 array is inverted by pouring into a micro mold prepared by a photolithography process, and then a thin film 12 of the same material is spin-coated to seal the entire microchannel 10. The liquid conductor eutectic gallium indium is injected to fill the entire channel. Finally, the electrode 2 is inserted at both ends of the microchannel 10 to be sealed again to complete the preparation. After the sensor is operated, the length and cross section of the microchannel 10 are changed due to the action of the external load, thereby changing the resistance. A constant current source is applied across the electrodes 2. The resistance signal is changed to a voltage signal that is convenient for measurement, and the corresponding strain value is obtained by analyzing the voltage signal. The flexible sensor still works properly when the strain reaches 300%. Works with virtually any complex 3D surface.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the present invention. Within the scope of protection of the invention.

Claims

Claim

[Claim 1] A flexible stretchable strain sensor, comprising: a flexible substrate having flexible microchannels therein, wherein the microchannels are provided with a liquid conductor or a semi-liquid conductor, the micro Electrodes are provided at both ends of the channel.

[Claim 2] A flexible tensile strain sensor according to claim 1, wherein the flexible substrate is made of a degradable polyester material or a silicone rubber material.

[Claim 3] A flexible tensile strain sensor according to claim 1, wherein a liquid conductor eutectic gallium indium is disposed in the microchannel.

[Aspect 4] A flexible tensile strain sensor according to any one of claims 1 to 3, wherein the microchannel is in the form of a strip, a line, a serpentine, a circle or an arc. Or or /, the microchannel is provided with one or at least two.

[Claim 5] A wearable device, characterized in that the wearable device has a flexible stretch strain sensor according to any one of claims 1 to 4.

[Claim 6] A method for preparing a flexible tensile strain sensor, comprising: preparing a flexible substrate having microchannels; and injecting a liquid conductor or a semi-liquid conductor into the microchannel Insert the electrodes at both ends of the channel.

[Claim 7] A method of manufacturing a flexible tensile strain sensor according to claim 6, wherein the preparing the flexible substrate comprises the following steps:

Preparing a microchannel mold and a flexible material solution, mixing the flexible material solution to remove bubbles; adding the flexible material solution after mixing and removing the bubbles into the microchannel mold to form a flexible matrix body;

A flexible material solution mixed and removed from the bubble is dropped onto the substrate, and the flexible material solution is formed into a film of a flexible material;

The flexible substrate body is pressed against the incompletely cured film of flexible material such that the flexible substrate body and the flexible material film form a flexible substrate having microchannels.

[Claim 8] A method of manufacturing a flexible tensile strain sensor according to claim 7, wherein injecting the liquid conductor or the semi-liquid conductor into the microchannel comprises the following steps: Two syringes are inserted into both ends of the microchannel, one of the syringes has a liquid conductor; the other syringe draws air in the microchannel, and a syringe having a liquid conductor injects a liquid conductor into the microchannel to make a liquid The conductor is filled with microchannels and the syringe is pulled out.

[Claim 9] A method of manufacturing a flexible tensile strain sensor according to claim 6, wherein inserting an electrode at both ends of the microchannel includes the following steps:

Two electrodes were inserted into each end of the microchannel, and the microchannel was sealed with a flexible material solution.

[Claim 10] A method of manufacturing a flexible tensile strain sensor according to claim 7, wherein mixing and removing the bubble of the flexible material solution comprises the following steps:

The Ecoflex series silicone rubber solution is placed in a container of a centrifugal mixer, the rotation speed of the centrifugal mixer is 300-400 rpm, and after maintaining the crucible for 10-15 s, the rotation speed of the centrifugal mixer is increased to 1400-1600 rpm, keeping The mixture is 25-30 s, and a mixed silicone rubber solution is obtained;

Putting the mixed silicone rubber solution into a vacuum suction device, and opening the vacuum pump of the vacuum suction device to obtain a silicone rubber solution after removing bubbles;

Forming the flexible substrate body includes the following steps:

Spraying at least one release agent film on the surface of the microchannel mold, and then filling the microchannel mold with a liquid silicone rubber solution by using a pipette; moving the microchannel mold into the oven at 80 Bake at 45 ° C for 45-60 min, and obtain a flexible matrix body after demolding;

The silicon rubber solution after removing the bubbles is dropped on the substrate, and is rotated into a homogenizer to form a silicone rubber film. The speed of the homogenizer is set to 350-400 rpm, and the uniformity of the glue is 25-30 seconds; The film is in a semi-solidified state, and the flexible substrate body after demolding is pressed on the silicone rubber film, and the flexible substrate body and the silicone rubber film are sealed and sealed, and left at room temperature for 45-60 minutes to obtain a flexible substrate with microchannels. .