阅读说明：本技术 具有多级微结构的弹性体薄膜及其制备方法与含该弹性体薄膜的柔性压力传感器 (Elastomer film with multi-stage microstructure, preparation method thereof and flexible pressure sensor containing elastomer film ) 是由 杨硕 程博闻 丁凯 王伟 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种具有多级微结构的弹性体薄膜及其制备方法与含该弹性体薄膜的柔性压力传感器,本发明采用模板法与静电纺丝相结合的工艺,所制备的弹性体薄膜单面具有随机分布的纤维网络组成的多级微结构,在稳定快速制备的同时满足低成本的需求。此外,静电纺丝技术在工业化实践中有大量应用,因此本发明的制备方法具有大规模产业化生产的应用前景。本发明制备的柔性压力传感器灵敏度高(＞63.93kPa～(-1))和较大的传感范围(＞160kPa),不仅对人体脉搏、声带发声等微小震动有强烈的响应,同时还对关节运动等较大的肢体运动有稳定的响应,在压力的实时监测中表现出良好的响应,应用潜力巨大。(The invention discloses an elastomer film with a multistage microstructure, a preparation method thereof and a flexible pressure sensor containing the elastomer film. In addition, the electrostatic spinning technology is widely applied in industrial practice, so that the preparation method has the application prospect of large-scale industrial production. The flexible pressure sensor prepared by the invention has high sensitivity (more than 63.93 kPa) ‑1 ) And a larger sensing range (more than 160 kPa) has strong response to micro vibration such as human body pulse, vocal cord sounding and the like, has stable response to larger limb movement such as joint movement and the like, shows good response in real-time monitoring of pressure, and has huge application potential.)

1. A preparation method of an elastomer film with a multilevel microstructure is characterized by comprising the following steps:

step one, processing and customizing a collecting template of electrostatic spinning;

changing a receiving device in the electrostatic spinning equipment from a roller into a collecting template, and debugging parameters of the electrostatic spinning equipment;

step three, preparing a thermoplastic polyurethane elastomer solution to obtain an electrostatic spinning solution;

step four, extracting electrostatic spinning solution, and spinning through electrostatic spinning equipment; and after spinning is finished, peeling the film from the collecting template to obtain the elastomer film with the multilevel microstructure.

2. The method as claimed in claim 1, wherein in the step one, the collecting template is a rectangular iron woven wire mesh with a pore density of 100-200 meshes.

3. The method for preparing the elastomer film with the multilevel microstructure according to claim 1, wherein in the second step, parameters of an electrospinning device are as follows: the spinning voltage is 10-11kV, the flow rate of the spinning solution is 1.0-1.2mL/h, the distance between the spinning nozzle and the receiving device is 13-15cm, and the spinning time is 2-3 h.

4. The method for preparing the elastomer film with the multilevel microstructure according to claim 1, wherein the thermoplastic polyurethane elastomer solution is prepared from thermoplastic polyurethane, tetrahydrofuran and N, N-dimethylformamide according to the ratio of 1: 2: 2 in mass ratio.

5. An elastomer film having a multilevel microstructure prepared by the preparation method of any one of claims 1 to 4.

6. A flexible pressure sensor having an elastomer film with a multilevel microstructure prepared by the preparation method of any one of claims 1 to 4.

7. The flexible pressure sensor according to claim 6, comprising a conductive layer, copper foil electrodes, wires and packaging materials, wherein the conductive layer is prepared by laminating surface layers with multilevel microstructures in a conductive elastomer film, the upper surface and the lower surface of the conductive layer are in contact with electrode surfaces of the copper foil electrodes, the copper foil electrodes are respectively connected with the wires, and finally the packaging materials are used for packaging.

8. The flexible pressure sensor of claim 7, wherein the conductive elastomer film is made by ultrasonic dipping of an elastomer film having a multilevel microstructure in a carbon nanotube dispersion.

9. The flexible pressure sensor of claim 8, wherein the carbon nanotube dispersion is formed from carbon nanotubes and a dispersion in a ratio of 1: 5000, the diameter of the carbon nano tube is 20-30nm, and the length of the carbon nano tube is 10-30 mu m; the dispersion is prepared by mixing one or more of methanol, ethanol and propanol with water in any proportion; the ultrasonic dipping power is 200W, the ultrasonic temperature is 10 ℃, and the ultrasonic time is 30-60 min.

10. The flexible pressure sensor of claim 7, wherein the copper foil electrode is 80-100 μm thick; the conducting wires are copper conducting wires or copper foils and are connected by adopting contact connection, soldering tin connection or conductive silver paste; the packaging material is polydimethylsiloxane, polyacrylate or ethylene oxide.

Technical Field

The invention belongs to the technical field of flexible pressure sensor manufacturing, and particularly relates to an elastomer film with a multistage microstructure, a preparation method of the elastomer film and a flexible pressure sensor containing the elastomer film.

Background

Under the push of numerous intelligent devices such as artificial skin, wearable electronic devices and health monitoring, flexible pressure sensors capable of monitoring and distinguishing fine pressure and deformation have received wide attention. A pressure sensor is a device that can sense a pressure signal and can convert the pressure signal into a usable electrical signal according to a certain rule, and the types of the pressure sensor are mainly three types: the sensor comprises a capacitance type, a piezoelectric type and a resistance type, wherein the resistance type flexible pressure sensor is particularly concerned by researchers due to the characteristics of simple integration process, easy signal collection, excellent sensing performance and the like, and has wide application prospect in the future.

In the past, researchers found that the formation of a microstructure on a conductive layer is an effective way to improve the sensing performance. For example, the invention patent with application number 201910156233.3 entitled "flexible pressure sensitive sensor and manufacturing method thereof" discloses a method for assembling an integrated flexible pressure sensitive sensor by preparing a bottom electrode and a pressure sensitive film through a magnetron sputtering process. Although the conductive layer with the microstructure is successfully prepared and the sensing performance is improved to a certain extent, the process is complex, has large loss and high cost, and is not suitable for being applied in industry. In order to find a more inexpensive and efficient microstructure preparation process, researchers utilize the principle of template imprinting to construct various microstructures by using lotus leaves (small, 2018, 14, 1800819), silk (adv. mater.2014, 26, 1336-. The sensing range of the sensor in the above studies is still at a low level. In addition, most of the design ideas of the current conducting layer are that a conducting material is deposited and dip-coated on the surface of the microstructure, most of the formed microstructure is solid, so that the microstructure is quickly saturated under the application of pressure, and the monitoring range of the sensor is small.

In summary, the development of the conductive layer with the multilevel microstructure has important value and significance for improving the sensitivity and the sensing range of the flexible pressure sensor, and meanwhile, a preparation process which is simple in process, low in cost and capable of realizing large-scale mass production is also urgently needed to be solved.

Disclosure of Invention

The invention provides an elastomer film with a multilevel microstructure and a preparation method thereof, aiming at the problems of low sensitivity, narrow sensing range, complex and unstable preparation process and difficulty in large-scale mass production of the conventional flexible pressure sensor.

The invention also provides a flexible pressure sensor containing the elastomer film.

The technical scheme of the invention is as follows:

a preparation method of an elastomer film with a multilevel microstructure comprises the following steps:

step one, processing and customizing a collecting template of electrostatic spinning;

changing a receiving device in the electrostatic spinning equipment from a roller into a collecting template, and debugging parameters of the electrostatic spinning equipment;

step three, preparing a Thermoplastic Polyurethane (TPU) elastomer solution to obtain an electrostatic spinning solution;

step four, extracting electrostatic spinning solution, and spinning through electrostatic spinning equipment; and after spinning is finished, peeling the film from the collecting template to obtain the elastomer film with the multilevel microstructure.

The single surface of the elastomer film with the multilevel microstructure prepared by the invention is provided with regular hill-shaped micro-bulges, and the interior of the elastomer film is provided with a randomly distributed fiber network.

In the first step, the collecting template is a rectangular iron woven wire mesh, and the pore density is 100-200 meshes.

In the second step, the parameters of the electrostatic spinning equipment are as follows: the spinning voltage is 10-11kV, the flow rate of the spinning solution is 1.0-1.2mL/h, the distance between the spinning nozzle and the receiving device is 13-15cm, and the spinning time is 2-3 h.

In the third step, the Thermoplastic Polyurethane (TPU) elastomer solution is prepared from thermoplastic polyurethane, tetrahydrofuran and N, N-dimethylformamide according to the weight ratio of 1: 2: 2 in mass ratio.

The invention also provides the elastomer film with the multilevel microstructure prepared by the preparation method of the elastomer film.

The invention also provides a flexible pressure sensor with the elastomer film with the multilevel microstructure, which is prepared by the elastomer film preparation method.

The flexible pressure sensor comprises a conducting layer, a copper foil electrode, a lead and a packaging material, wherein the conducting layer is formed by oppositely laminating surface layers with multi-stage microstructures in a conducting elastomer film, the upper surface and the lower surface of the conducting layer are in contact with electrode surfaces of the copper foil electrode, the copper foil electrode is respectively connected with the lead, and finally the packaging material is used for packaging.

The conductive elastomer film is prepared by ultrasonically dipping the elastomer film with the multilevel microstructure in the carbon nano tube dispersion liquid.

The carbon nanotube dispersion liquid is prepared by mixing carbon nanotubes and the dispersion liquid according to the weight ratio of 1: 5000, the diameter of the carbon nano tube is 20-30nm, and the length of the carbon nano tube is 10-30 mu m; the dispersion is prepared by mixing one or more of methanol, ethanol and propanol with water in any proportion; the ultrasonic dipping power is 200W, the ultrasonic temperature is 10 ℃, and the ultrasonic time is 30-60 min.

The thickness of the copper foil electrode is 80-100 mu m; the conducting wires are copper conducting wires or copper foils and are connected by adopting contact connection, soldering tin connection or conductive silver paste; the packaging material is polydimethylsiloxane, polyacrylate or ethylene oxide.

The copper foil electrode is an axe-shaped electrode obtained through a precision cutting process.

Compared with the prior art, the invention has the beneficial effects that:

1. the elastomer film prepared by the invention is different from the traditional polymer solid microstructure, and the multi-stage microstructure elastomer film with regular hill-shaped micro-protrusions on the single surface and randomly distributed fiber networks inside is prepared by process templating electrostatic spinning (a process combining templating and electrostatic spinning).

2. Compared with the traditional method for preparing the solid microstructure by silicon film etching, 3D printing, leaf transfer printing, silk printing and the like, the preparation method of the elastomer film with the multistage microstructure adopts a process of combining a template method and electrostatic spinning, and the prepared elastomer film with the multistage microstructure formed by randomly distributed fiber networks on one side meets the requirements of low cost while being stably and quickly prepared. In addition, the electrostatic spinning technology is widely applied in industrial practice, so that the preparation method has the application prospect of large-scale industrial production.

3. The flexible pressure sensor prepared by the invention has high sensitivity (more than 63.93 kPa)^-1) And a larger sensing range (more than 160 kPa) has strong response to micro vibration such as human body pulse, vocal cord sounding and the like, has stable response to larger limb movement such as joint movement and the like, shows good response in real-time monitoring of pressure, and has huge application potential.

Drawings

FIG. 1 is a collection template for electrospinning according to the present invention;

FIG. 2 is a three-dimensional model of an elastomeric film having a multi-level microstructure made in accordance with the present invention;

FIG. 3 is a flexible pressure sensor having an elastomeric membrane with a multi-level microstructure made in accordance with the present invention;

in the figure, 1, a conductive layer, 2, an electrode, 3, a lead, 4 and packaging materials;

FIGS. 4a-c are SEM images of collection templates, SEM images of elastomer films, SPM images of elastomer films and cross-sectional SEM images of elastomer films prepared in examples 1-3 of the present invention;

FIG. 5 is a schematic diagram of a pressure-current curve for a flexible pressure sensor in accordance with the present invention;

FIG. 6 is a graph of the current response of the flexible pressure sensor of the present invention for a relatively small pressure;

in fig. 7, a is a photograph of the flexible pressure sensor of the present invention attached to the knee and a graph of current versus time when the knee is bent; b is a picture of the flexible pressure sensor attached to the wrist of a person, a graph of the relationship between current and time during pulse beat and an enlarged view of single pulse beat.

Detailed Description

For a further understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings

A preparation method of an elastomer film with a multilevel microstructure comprises the following steps:

step one, processing and customizing a collecting template of electrostatic spinning;

changing a receiving device in the electrostatic spinning equipment from a roller into a collecting template, and debugging parameters of the electrostatic spinning equipment;

electrospinning is a special fiber manufacturing process in which a polymer solution or melt is jet spun in a strong electric field, under the action of which the droplets at the needle change from spherical to conical (i.e., taylor cone) and a fiber filament is obtained extending from the tip of the cone. In this way, polymer filaments of nanometer-scale diameter can be produced.

Step three, preparing a Thermoplastic Polyurethane (TPU) elastomer solution to obtain an electrostatic spinning solution;

step four, extracting electrostatic spinning solution, and spinning through electrostatic spinning equipment; and after spinning is finished, peeling the film from the collecting template to obtain the elastomer film with the multilevel microstructure.

The elastomer film with the multilevel microstructure prepared by the invention is shown in figure 2, and has regular hill-shaped micro-protrusions on one surface and a randomly distributed fiber network inside. The regular hill-shaped micro-protrusions on the surface of the elastomer film are formed by stacking hill-shaped regular microstructures due to the fact that an electrostatic spinning device of a rectangular iron woven wire mesh is used, an electric field structure is changed in the electrostatic spinning process, and more fibers are driven by electrostatic force to gather to the longitude and latitude intersections of the iron woven wire mesh; while the fibers inside the elastomeric film are formed by the stretching effect of electrostatic forces.

In the first step, the collecting template is a rectangular iron woven wire mesh, and the pore density is 100-200 meshes. The collection template of the present invention is shown in fig. 1.

In the second step, the parameters of the electrostatic spinning equipment are as follows: the spinning voltage is 10-11kV, the flow rate of the spinning solution is 1.0-1.2mL/h, the distance between the spinning nozzle and the receiving device is 13-15cm, and the spinning time is 2-3 h.

In the third step, the Thermoplastic Polyurethane (TPU) elastomer solution is prepared from thermoplastic polyurethane, tetrahydrofuran and N, N-dimethylformamide according to the weight ratio of 1: 2: 2 in mass ratio.

The invention also provides the elastomer film with the multilevel microstructure prepared by the preparation method of the elastomer film.

The invention also provides a flexible pressure sensor with the elastomer film with the multilevel microstructure, which is prepared by the elastomer film preparation method.

The flexible pressure sensor comprises a conducting layer, a copper foil electrode, a lead and a packaging material, wherein the conducting layer is formed by oppositely laminating surface layers with multi-stage microstructures in a conducting elastomer film, the upper surface and the lower surface of the conducting layer are in contact with electrode surfaces of the copper foil electrode, the copper foil electrode is respectively connected with the lead, and finally the packaging material is used for packaging. The structure of the flexible pressure sensor is shown in figure three.

The mechanism of the flexible pressure sensor prepared by the invention is as follows: the conductive layer is prepared by laminating surface layers with multilevel microstructures in the conductive elastomer film, hillock-shaped micro-protrusions in the conductive layer are contacted with each other to form a conductive path under the condition of no pressure application, and the protrusions are contacted with each other to form the initial resistance of the device; when pressure is applied, the protrusions are subjected to compressive deformation under the action of force, so that the contact area between the protrusions is increased, and further the resistance is changed; along with the increase of the applied pressure, the extrusion deformation of the protrusions is larger and larger, and when the deformation saturation is reached, the contact area between the protrusions is not changed; another response mechanism is triggered at this point, and the increasing pressure causes the contact points of the fibers within the conductive layer to increase, thereby continuing to cause a change in resistance. When the external force is eliminated, the compressive contact in the layer and the deformation of the surface bulge can be restored to the original state, so that the resistance of the device returns to the initial state. Based on the change of the resistance of the pressure sensor, the change of the resistance of the device under constant voltage or the change of the current of the device under constant voltage can be tested, and the magnitude of the applied pressure is further calculated.

The conductive elastomer film is prepared by ultrasonically dipping the elastomer film with the multilevel microstructure in the carbon nano tube dispersion liquid.

The carbon nanotube dispersion liquid is prepared by mixing carbon nanotubes and the dispersion liquid according to the weight ratio of 1: 5000, the diameter of the carbon nano tube is 20-30nm, and the length of the carbon nano tube is 10-30 mu m; the dispersion is prepared by mixing one or more of methanol, ethanol and propanol with water in any proportion; the ultrasonic dipping power is 200W, the ultrasonic temperature is 10 ℃, and the ultrasonic time is 30-60 min.

The thickness of the copper foil electrode is 80-100 mu m; the conducting wires are copper conducting wires or copper foils and are connected by adopting contact connection, soldering tin connection or conductive silver paste; the packaging material is polydimethylsiloxane, polyacrylate or ethylene oxide.

The copper foil electrode is an axe-shaped electrode obtained through a precision cutting process.

The flexible pressure sensor disclosed by the invention is widely applied, has strong response to micro vibration such as human body pulse, vocal cord sounding and the like, also has stable response to larger limb movement such as joint movement and the like, and shows good response in real-time monitoring of pressure.

The present invention will be further described with reference to the following examples.

Example 1

A preparation method of an elastomer film is prepared by the following steps:

step one, processing and customizing a collecting template of electrostatic spinning;

changing a receiving device in the electrostatic spinning equipment from a roller into a collecting template, and debugging parameters of the electrostatic spinning equipment;

step three, preparing a Thermoplastic Polyurethane (TPU) elastomer solution to obtain an electrostatic spinning solution;

step four, extracting electrostatic spinning solution, and spinning through electrostatic spinning equipment; after spinning, the film is peeled from the collecting template to obtain an elastomer film with no protrusions on the surface and randomly distributed fiber grids inside.

The surface roughness of the elastomeric film prepared in this example was 9.431.

In the first step, a rectangular iron woven wire mesh with the template length of 40cm and the width of 20cm is collected, and the pore density is 0 mesh.

In the second step, the parameters of the electrostatic spinning equipment are as follows: the spinning voltage is 11kV, the flow rate of the spinning solution is 1.0mL/h, the distance between the spinning nozzle and the receiving device is 15cm, and the spinning time is 2 h.

In the third step, the Thermoplastic Polyurethane (TPU) elastomer solution is prepared from thermoplastic polyurethane, tetrahydrofuran and N, N-dimethylformamide according to the weight ratio of 1: 2: 2 in mass ratio.

The embodiment also provides the elastomer film which is prepared by the elastomer film preparation method and has no protrusions on the surface and randomly distributed fiber grids inside.

In fig. 4, a is an SEM picture of the collection template, an SEM picture of the elastomer film, an SPM picture of the elastomer film, and a cross-sectional SEM picture of the elastomer film prepared in example 1 of the present invention.

Example 2

A preparation method of an elastomer film with a multilevel microstructure comprises the following steps:

step one, processing and customizing a collecting template of electrostatic spinning;

changing a receiving device in the electrostatic spinning equipment from a roller into a collecting template, and debugging parameters of the electrostatic spinning equipment;

step three, preparing a Thermoplastic Polyurethane (TPU) elastomer solution to obtain an electrostatic spinning solution;

step four, extracting electrostatic spinning solution, and spinning through electrostatic spinning equipment; and after spinning is finished, peeling the film from the collecting template to obtain the elastomer film with the multilevel microstructure.

The elastomer film with the multilevel microstructure prepared in the embodiment has regular hill-shaped micro-protrusions on one surface, a randomly distributed fiber network inside, and the surface roughness of the elastomer film is 13.645.

In the first step, the collecting template is a rectangular iron woven wire mesh, and the pore density is 100 meshes.

In the second step, the parameters of the electrostatic spinning equipment are as follows: the spinning voltage is 11kV, the flow rate of the spinning solution is 1.0mL/h, the distance between the spinning nozzle and the receiving device is 15cm, and the spinning time is 2 h.

In the third step, the Thermoplastic Polyurethane (TPU) elastomer solution is prepared from thermoplastic polyurethane, tetrahydrofuran and N, N-dimethylformamide according to the weight ratio of 1: 2: 2 in mass ratio.

The invention also provides the elastomer film with the multilevel microstructure prepared by the preparation method of the elastomer film.

In fig. 4, b is an SEM image of the collection template, an SEM image of the elastomer film, an SPM image of the elastomer film, and a cross-sectional SEM image of the elastomer film prepared in example 2 of the present invention.

Example 3

A preparation method of an elastomer film with a multilevel microstructure comprises the following steps:

step one, processing and customizing a collecting template of electrostatic spinning;

changing a receiving device in the electrostatic spinning equipment from a roller into a collecting template, and debugging parameters of the electrostatic spinning equipment;

step three, preparing a Thermoplastic Polyurethane (TPU) elastomer solution to obtain an electrostatic spinning solution;

step four, extracting electrostatic spinning solution, and spinning through electrostatic spinning equipment; and after spinning is finished, peeling the film from the collecting template to obtain the elastomer film with the multilevel microstructure.

The single surface of the elastomer film with the multilevel microstructure prepared in the embodiment has regular hill-shaped micro-protrusions, the interior of the elastomer film has a randomly distributed fiber network, and the surface roughness of the elastomer film is 11.104.

In the first step, the collecting template is a rectangular iron woven wire mesh, and the pore density is 200 meshes.

In the second step, the parameters of the electrostatic spinning equipment are as follows: the spinning voltage is 10kV, the flow rate of the spinning solution is 1.2mL/h, the distance between the spinning nozzle and the receiving device is 13cm, and the spinning time is 3 h.

In the third step, the Thermoplastic Polyurethane (TPU) elastomer solution is prepared from thermoplastic polyurethane, tetrahydrofuran and N, N-dimethylformamide according to the weight ratio of 1: 2: 2 in mass ratio.

The invention also provides the elastomer film with the multilevel microstructure prepared by the preparation method of the elastomer film.

In FIG. 4, c is an SEM photograph of the collection template, an SEM photograph of the elastomer film, an SPM photograph of the elastomer film, and a cross-sectional SEM photograph of the elastomer film prepared in examples 1 to 4 of the present invention.

Example 4

The embodiment provides the flexible pressure sensor with the elastomer film with the multilevel microstructure, which is prepared by the elastomer film preparation method.

The flexible pressure sensor comprises a conducting layer, a copper foil electrode, a lead and a packaging material, wherein the conducting layer is formed by oppositely laminating surface layers with multi-stage microstructures on one surface of a conducting elastomer film, the upper surface and the lower surface of the conducting layer are in contact with electrode surfaces of the copper foil electrode, the copper foil electrode is respectively connected with the lead, and finally the packaging material is used for packaging.

The conductive elastomer film is prepared by ultrasonically dipping the elastomer film with the multilevel microstructure prepared in the example 2 in the carbon nano tube dispersion liquid.

The carbon nanotube dispersion liquid is prepared by mixing carbon nanotubes and the dispersion liquid according to the weight ratio of 1: 5000, the diameter of the carbon nano tube is 20-30nm, and the length of the carbon nano tube is 10-30 mu m; the dispersion is propanol; the ultrasonic impregnation power is 200W, the ultrasonic temperature is 10 ℃, and the ultrasonic time is 45 min.

The thickness of the copper foil electrode is 90 mu m; the conducting wires are copper conducting wires and are connected by adopting conductive silver paste; the packaging material is polydimethylsiloxane.

The copper foil electrode is an axe-shaped electrode obtained through a precision cutting process.

Applying 1V voltage to two ends of a lead-out wire through a digital source meter measuring unit (SMU) to measure different conditions of the flexible pressure sensorAnd obtaining a current-voltage curve of the sensor by corresponding change of the current under the pressure, and further obtaining the sensitivity of different sections. The flexible pressure sensor shows extremely high sensitivity of 63.93kPa through detection^-1A monitoring range of up to 160kPa and an extremely low detection lower limit of 0.7Pa, the results are shown in fig. 5 and 6.

The flexible pressure sensor prepared in example 4 was attached to the knee joint as shown in fig. 7 a. When the knee joint bends and stretches each time, the electric signal fluctuates in a fluctuating-falling mode, and the frequency of the waveform is the same as that of bending of an experimenter, so that the flexible pressure sensor has better stability and force-electric response. In addition, when the flexible pressure sensor prepared in example 5 was attached to the wrist, it was shown in fig. 7 b. The sensor responds intact to the frequency and waveform of the pulse. As can be seen from the signal waveform, the wrist pulse frequency of the testee is about 62 times/min, which is the same as that of the adult. In addition, as can be seen from the illustration in fig. 7b, the flexible pressure sensor of the present invention can distinguish characteristic peaks of pulse waveforms, i.e., P (shock) wave, T (tide) wave and D (diastolic) wave, which indicates that the present invention has high sensitivity, so that weak vibrations such as pulse vibrations can be detected, and the present invention has potential for being applied to intelligent wearable electronic devices in the future.

Example 5

The embodiment provides the flexible pressure sensor with the elastomer film with the multilevel microstructure, which is prepared by the elastomer film preparation method.

The flexible pressure sensor comprises a conducting layer, a copper foil electrode, a lead and a packaging material, wherein the conducting layer is formed by oppositely laminating surface layers with multi-stage microstructures on one surface of a conducting elastomer film, the upper surface and the lower surface of the conducting layer are in contact with electrode surfaces of the copper foil electrode, the copper foil electrode is respectively connected with the lead, and finally the packaging material is used for packaging.

The conductive elastomer film is prepared by ultrasonically dipping the elastomer film with the multilevel microstructure in the carbon nano tube dispersion liquid.

The carbon nanotube dispersion liquid is prepared by mixing carbon nanotubes and the dispersion liquid according to the weight ratio of 1: 5000, the diameter of the carbon nano tube is 20-30nm, and the length of the carbon nano tube is 10-30 mu m; the dispersion is methanol; the ultrasonic dipping power is 200W, the ultrasonic temperature is 10 ℃, and the ultrasonic time is 60 min.

The thickness of the copper foil electrode is 100 mu m; the lead is a copper foil and is connected in a contact manner; the packaging material is polyacrylate.

The copper foil electrode is an axe-shaped electrode obtained through a precision cutting process.

Example 6

The invention also provides a flexible pressure sensor with the elastomer film with the multilevel microstructure, which is prepared by the elastomer film preparation method.

The flexible pressure sensor comprises a conducting layer, a copper foil electrode, a lead and a packaging material, wherein the conducting layer is formed by oppositely laminating surface layers with multi-stage microstructures in a conducting elastomer film, the upper surface and the lower surface of the conducting layer are in contact with electrode surfaces of the copper foil electrode, the copper foil electrode is respectively connected with the lead, and finally the packaging material is used for packaging.

The conductive elastomer film is prepared by ultrasonically dipping the elastomer film with the multilevel microstructure in the carbon nano tube dispersion liquid.

The carbon nanotube dispersion liquid is prepared by mixing carbon nanotubes and the dispersion liquid according to the weight ratio of 1: 5000, the diameter of the carbon nano tube is 20-30nm, and the length of the carbon nano tube is 10-30 mu m; the dispersion liquid is ethanol; the ultrasonic dipping power is 200W, the ultrasonic temperature is 10 ℃, and the ultrasonic time is 30 min.

The thickness of the copper foil electrode is 80 mu m; the conducting wires are copper conducting wires and are connected by adopting soldering tin; the packaging material is ethylene oxide.

The copper foil electrode is an axe-shaped electrode obtained through a precision cutting process.

The foregoing examples, which are merely illustrative of the present invention and are preferred embodiments, are described in some detail and are not to be construed as limiting the scope of the present patent. It should be noted that the present invention is not limited to the above-mentioned embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should be included in the scope of the present invention.