CN115290231A - Microstructure elastomer film, preparation method thereof, flexible pressure sensor and preparation method thereof - Google Patents
Microstructure elastomer film, preparation method thereof, flexible pressure sensor and preparation method thereof Download PDFInfo
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Images
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/18—Measuring force or stress, in general using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/024—Detecting, measuring or recording pulse rate or heart rate
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/024—Detecting, measuring or recording pulse rate or heart rate
- A61B5/0245—Detecting, measuring or recording pulse rate or heart rate by using sensing means generating electric signals, i.e. ECG signals
Abstract
The invention provides a microstructure elastomer film, which comprises a substrate and a microstructure layer attached to the surface of a matrix; the microstructure layer is provided with a granular microstructure which is small in the lower end part connected with the substrate, large in the upper end, rough in surface and fluffy in the interior; or a mountain-vein-shaped microstructure which is connected with the substrate, has a large lower end part, a small upper end, a rough surface and a fluffy interior; or a fabric-like microstructure with interlaced fibers. The invention also provides a preparation method of the microstructure elastomer film based on the spraying process, and the invention also provides a flexible pressure sensor and a preparation method thereof.
Description
Technical Field
The invention belongs to the technical field of pressure sensors, and particularly relates to a micro-structure elastomer film, a preparation method of the micro-structure elastomer film, a flexible pressure sensor and a preparation method of the flexible pressure sensor.
Background
The flexible pressure sensor has the characteristics of lightness, thinness and flexibility, can be attached to the surface with a complex shape, is convenient to carry, and has wide application prospects in the fields of electronic skin, health monitoring, human-computer interaction, motion recognition and the like. The piezoresistive flexible pressure sensor has the advantages of simple structure, easy signal reading and convenient manufacture, and is widely concerned. The sensing mechanism of the piezoresistive flexible pressure sensor can be divided into bulk phase conduction and surface conduction. Bulk phase conduction means that conductive fillers are uniformly dispersed in an elastomer, but the sensor adopting the mechanism is greatly influenced by the viscoelasticity and temperature change of the material, so that an output signal is unstable. The surface microstructure is a device structure developed aiming at the defect of bulk phase conductivity, the surface microstructure of the elastic film of the sensor deforms when being pressed, the contact area between the conductive film and the interdigital electrode is enlarged, and the contact resistance is reduced, so that the force-electricity conversion is realized.
In recent years, the performance of microstructure-type flexible pressure sensors has been greatly improved under the efforts of researchers. The microstructures currently used by researchers are mostly obtained from the surface of the microstructure by a transfer printing method. For example, in the invention patent with application number 202111156003.0 entitled "a method for manufacturing a flexible pressure sensor and application thereof", sand paper is used as a template, multi-walled carbon nanotubes (MWCNTs) are used as a conductive material, and Polydimethylsiloxane (PDMS) is used as a flexible substrate to obtain a microstructure flexible sensing layer, but the problem of small linear interval exists. In order to expand the linear range of the sensor, the invention patent with the application number of 201910240874.7 and the name of 'an elastomer film and a preparation method thereof and a flexible pressure sensor containing the elastomer film' adopts the selective laser sintering 3D printing technology to prepare the microstructure template, and the obtained microstructure sensing film has good linear response in the pressure range of 200kPa, thereby improving the performance of the sensor.
However, the transfer method has disadvantages that prevent commercialization of the flexible pressure sensor. Firstly, the transfer printing method is limited by the operation layers such as the size of a template, the leveling requirement of an elastomer, the separation of a film and the template and the like, and cannot realize large-area production; secondly, the microstructure of the template is abraded in the process of multiple use, so that the production quality is unstable; finally, the processing of the template and the usual elastomeric material (PDMS) make the template method more expensive, while the complexity of the transfer operation makes it less efficient. The preparation of the microstructure elastomer film by a non-transfer printing method is also reported, for example, the preparation of the microstructure film with a certain area can be realized by adopting an electrostatic spinning technology in the application number of 202110855000.X, namely the elastomer film with a multilevel microstructure, the preparation method thereof and a flexible pressure sensor containing the elastomer film, but the problems of low production efficiency and small linear range exist. In conclusion, the development of a method for preparing the high-performance micro-structure elastomer film in a non-transfer printing manner, a large area, high efficiency and low cost has important significance for promoting the commercial application of the flexible pressure sensor.
Disclosure of Invention
The invention aims to provide a preparation method of a micro-structure elastomer film and a preparation method of a flexible pressure sensor, the preparation method of the micro-structure elastomer film is easy to industrialize, and the flexible pressure sensor prepared based on the micro-structure film has a good linear relation between a current signal and pressure within a wide range of 20000kPa and can be used for monitoring radial artery pulse.
The invention provides a microstructure elastomer film, which comprises a substrate and a microstructure layer attached to the surface of a matrix;
the microstructure layer is provided with a granular microstructure which is small in lower end part connected with the substrate, large in upper end, rough in surface and fluffy in the interior; or a mountain-vein-shaped microstructure which is connected with the substrate, has a large lower end part, a small upper end, a rough surface and a fluffy interior; or a fabric-like microstructure with interlaced fibers.
Preferably, the substrate is a polyethylene terephthalate film, a thermoplastic polyurethane elastomer film, a polyethylene film, a polypropylene film or a polyimide film;
the thickness of the substrate is 50-100 μm.
The present invention provides a method of making a microstructured elastomeric film as described above, comprising the steps of:
a) Dissolving a thermoplastic elastomer material in a solvent to prepare an elastomer solution with the concentration of 10-120 mg/mL;
the thermoplastic elastomer material is one or more of hydrogenated styrene-butadiene block copolymer and thermoplastic polyurethane; the solvent is one or more of tetrahydrofuran, butyl acetate, 1, 4-dioxane, cyclohexanone and N, N-dimethylformamide;
b) And uniformly spraying the elastomer solution on the surface of a substrate, and removing the solvent to obtain the microstructure elastomer film.
Preferably, the elastomer solution is sprayed onto the substrate surface using an air-assisted spray gun; the carrier gas pressure of the spraying is 0.1-0.8 MPa; the diameter of the nozzle is 0.8-2.5 mm; the spraying distance is 20-50 cm.
Preferably, the microstructured elastomeric film has a thickness of 50 to 300 μm.
Preferably, the solvent is removed by heating or volatilization at room temperature.
The present invention provides a flexible pressure sensor comprising a microstructured elastomeric film as described above.
The invention provides a preparation method of a flexible pressure sensor, which comprises the following steps:
1) Obtaining a microstructured elastomeric film according to the preparation method described above;
2) Forming a conductive layer on the surface of the micro-structure elastomer film to obtain a sensing film;
3) And combining and packaging one side of the conducting layer of the sensing film and the interdigital electrode to obtain the flexible pressure sensor.
Preferably, spraying conductive ink on the surface of the micro-structure elastomer film to form a conductive layer;
or forming a metal conducting layer on the surface of the microstructure elastomer film through magnetron sputtering or vacuum evaporation.
Preferably, the conductive ink is an organic dispersion of a conductive carbon material; the thickness of the conductive layer is 1-2 μm.
The invention provides a micro-structure elastomer film, which comprises a substrate and a micro-structure layer attached to the surface of a substrate; the microstructure layer is provided with a granular microstructure which is small in the lower end part connected with the substrate, large in the upper end, rough in surface and fluffy in the interior; or a mountain-like microstructure which is connected with the substrate, has a large lower end part, a small upper end, a rough surface and a fluffy interior; or a fabric-like microstructure with interlaced fibers.
The invention provides a preparation method of a microstructure elastomer film, which comprises the following steps: a) Dissolving a thermoplastic elastomer material in a solvent to prepare an elastomer solution with the concentration of 10-120 mg/mL; the elastomer material is one or more of hydrogenated styrene-butadiene block copolymer and thermoplastic polyurethane; the solvent is one or more of tetrahydrofuran, butyl acetate, 1, 4-dioxane, cyclohexanone and N, N-dimethylformamide; b) And uniformly spraying the elastomer solution on the surface of a substrate, and removing the solvent to obtain the microstructure elastomer film. The preparation method of the elastomer film is mainly based on a spraying process. Firstly, selecting a proper soluble elastomer high polymer material, preparing the soluble elastomer high polymer material into a solution with a certain concentration, then spraying the solution on a temperature-controlled substrate by using an air-assisted spray gun to form a film, and volatilizing the solution to obtain the elastomer film with a multilayer surface microstructure. The current signal and the pressure of the flexible pressure sensor prepared by the film show good linear relation in the range of 20000kPa, and the flexible pressure sensor can be used for monitoring the pulse of the radial artery.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is an optical microscope side view of a microstructured elastomeric film made in accordance with example 1 of the present invention;
FIG. 2 is an SEM image of a microstructured elastomeric film made according to example 1 of the present invention;
FIG. 3 is a top plan view of an optical microscope showing a microstructured elastomeric film made in accordance with example 2 of the present invention;
FIG. 4 is an optical microscope photograph of a microstructured elastomeric film made in accordance with example 3 of the present invention;
FIG. 5 is an SEM image of a microstructured elastomeric film made in accordance with example 3 of the present invention;
FIG. 6 is an SEM image of a microstructured elastomeric film made according to example 4 of the present invention;
FIG. 7 is a linear test chart of the flexible pressure sensor in example 6 of the present invention at 0 to 20 MPa;
fig. 8 is a pulse testing chart of the flexible pressure sensor according to embodiment 6 of the present invention.
Detailed Description
The invention provides a micro-structure elastomer film, which comprises a substrate and a micro-structure layer attached to the surface of the substrate;
the microstructure layer is provided with a granular microstructure which is small in the lower end part connected with the substrate, large in the upper end, rough in surface and fluffy in the interior; or a mountain-vein-shaped microstructure which is connected with the substrate, has a large lower end part, a small upper end, a rough surface and a fluffy interior; or a fabric-like microstructure with interlaced fibers.
In the invention, the microstructure layer has three morphologies, which are respectively:
1) The bottom end part connected with the substrate is small, the upper end is expanded, the surface is rough, the interior is fluffy, and the appearance similar to that of broccoli is presented;
the granular microstructures are distributed randomly at spatial positions on the surface of the substrate, the height distribution of the granules is relatively even, the microstructures with the characteristic of small bottom and large top cannot be obtained by a transfer printing method (difficult to demould), reports of similar structures processed by other processes are not seen, and the microstructures are further used for flexible pressure sensors.
2) The shape of a mountain is that the lower part is large and the upper part is small, the connection is continuous, the surface is rough and the interior is fluffy;
3) The fiber-shaped filaments are staggered and criss-cross, and the overall surface height is not large.
The invention provides a preparation method of a microstructure elastomer film, which comprises the following steps:
a) Dissolving a thermoplastic elastomer material in a solvent to prepare an elastomer solution with the concentration of 10-120 mg/mL;
the elastomer material is one or more of hydrogenated styrene-butadiene block copolymer and thermoplastic polyurethane; the solvent is one or more of tetrahydrofuran, butyl acetate, 1, 4-dioxane, cyclohexanone and N, N-dimethylformamide;
b) And uniformly spraying the elastomer solution on the surface of a substrate, and removing the solvent to obtain the microstructure elastomer film.
In the invention, the preparation of the microstructure elastomer film by using the spray coating method needs to select a proper elastomer material, wherein the elastomer material is preferably one or more of hydrogenated styrene-butadiene block copolymer (SEBS) and Thermoplastic Polyurethane (TPU); the solvent is preferably one or more of tetrahydrofuran, butyl acetate, 1, 4-dioxane, cyclohexanone and N, N-dimethylformamide, and more preferably a low boiling point solvent such as Tetrahydrofuran (THF).
The applicant has found that the concentration of the elastomeric material directly affects the microstructure morphology of the surface of the microstructured elastomeric film, and in the present invention, the concentration of the elastomeric material is preferably 10 to 120mg/mL, such as 10mg/mL,15mg/mL,20mg/mL,25mg/mL,30mg/mL,35mg/mL,40mg/mL,45mg/mL,50mg/mL,55mg/mL,60mg/mL,65mg/mL,70mg/mL,75mg/mL,80mg/mL,85mg/mL,90mg/mL,95mg/mL,100mg/mL,105mg/mL,110mg/mL,115mg/mL,120mg/mL, and preferably ranges in which any of the above values is an upper limit or a lower limit.
In the invention, the liquid drops sprayed by the solution with low concentration (10-30 mg/mL) can be well dispersed to obtain a Broccoli (Broccoli) shaped microstructure; the viscosity of the solution with medium concentration (30-70 mg/mL) is increased, the solution cannot be well dispersed during spraying, a part of wire drawing occurs, and at the moment, the microstructure is mountain-shaped, large at the bottom and small at the top, and continuous; the solution concentration is continuously increased (70-120 mg/mL), the sprayed filaments are mainly filaments, a fabric-like surface is obtained, the fibrous filaments are staggered and criss-cross, and the overall surface height is not large.
After the elastomer solution is obtained, the elastomer solution is uniformly sprayed on the surface of the substrate in a spraying mode. The walking path of the spraying is a snake-shaped curve, and the path parameters are adjusted according to the area of the substrate and the spraying amplitude to ensure uniform coverage.
The spraying method used by the invention can be used for quickly and uniformly preparing the elastomer films with various different microstructure appearances in a large area. In the spraying process of the pneumatic spray gun, the feed liquid flows out from the nozzle to form a liquid film under the action of gravity or pressure in the storage tank. The surface of the liquid film generates unstable fluctuation under the action of surrounding high-speed gas jet flow, and the liquid film is broken into liquid lines, liquid rings or larger particles along with the development of the fluctuation and moves forwards away from the nozzle. The liquid drops formed by the primary fracture can continuously be acted by rear airflow in the air, and when the gas acting force is greater than the surface tension and the internal viscous force of the liquid, the liquid drops formed by the primary fracture can be secondarily fractured to obtain finer spray liquid drops. The droplets will partially collide and merge while continuing to fly forward, eventually striking the substrate and adhering to its surface. By changing the spraying parameters such as carrier gas flow rate, feed liquid components, base materials, spraying speed and the like, different atomization and drying effects can be realized, and surface microstructure films with different appearances can be obtained.
The present invention preferably sprays the elastomer solution using an air-assisted spray gun having a nozzle diameter of preferably 0.8 to 2.5mm, more preferably 1 to 2mm, and a carrier gas pressure of preferably 0.1 to 0.8MPa, more preferably 0.3 to 0.5MPa, such as 0.1MPa,0.2MPa,0.3MPa,0.4MPa,0.5MPa,0.6MPa,0.7MPa,0.8MPa, preferably a range value having any of the above values as an upper limit or a lower limit; the distance of the spraying is preferably 20 to 50cm, more preferably 30 to 40cm.
After the solvent is volatilized and the surface is dried after each spraying, the spraying process can be repeated for multiple times until the required thickness is reached, and the elasticity of the film is ensured.
The solvent in the sprayed layer is preferably removed by heating, and particularly, a temperature-controllable heating device can be arranged below the substrate, or an infrared radiation lamp is used for heating from the top. The heating temperature in the present invention is preferably 70 to 150 c, more preferably 90 c, because the heating temperature is adjusted according to the kind of the solvent and the base material resistance temperature and the elastomer resistance temperature are taken into consideration.
In the present invention, the thickness of the elastomer microstructure layer prepared by the spray coating method is preferably 50 to 300 μm, more preferably 100 to 200 μm.
In the present invention, the substrate is preferably a polyethylene terephthalate (PET) film, a TPU film, a Polyethylene (PE) film, a polypropylene (PP) film or a Polyimide (PI) film, and the thickness of the substrate is preferably 50 to 100 μm, and more preferably 60 to 80 μm.
The invention also provides a flexible pressure sensor comprising the microstructured elastomeric film described above.
Based on the preparation method of the microstructure elastomer film, the invention also provides a preparation method of the flexible pressure sensor, which comprises the following steps:
1) Obtaining a microstructured elastomeric film according to the preparation method described above;
2) Forming a conductive layer on the surface of the microstructure elastomer film to obtain a sensing film;
3) And combining and packaging one side of the conducting layer of the sensing film and the interdigital electrode to obtain the flexible pressure sensor.
In the invention, the conductive layer can be formed by spraying conductive ink on the surface of the microstructure elastomer by an air-assisted spraying or ultrasonic spraying method, or a metal conductive layer can be constructed on the surface of the microstructure by a magnetron sputtering or vacuum evaporation method.
In the present invention, the conductive ink preferably comprises a conductive carbon material and an organic solvent, and specifically, a N, N-Dimethylformamide (DMF) dispersion of multi-walled carbon nanotubes may be used, and the concentration is preferably 1 to 10mg/mL, more preferably 3 to 8mg/mL, and most preferably 5 to 6mg/mL; the metal in the metal conductive layer may be gold or silver.
And after the sensing film is obtained, combining and packaging one side of the conducting layer of the sensing film and the interdigital electrode to obtain the flexible pressure sensor. In the present invention, the interdigital electrode is preferably a PI substrate, a silver conductive layer.
The invention provides a preparation method of a microstructure elastomer film, which comprises the following steps: a) Mixing an elastomer material with a solvent to prepare an elastomer solution with the concentration of 10-120 mg/mL; the elastomer material is one or more of hydrogenated styrene-butadiene block copolymer and thermoplastic polyurethane; the solvent is one or more of tetrahydrofuran, butyl acetate, 1, 4-dioxane, cyclohexanone and N, N-dimethylformamide; b) And uniformly spraying the elastomer solution on the surface of a substrate, and removing the solvent to obtain the microstructure elastomer film. The preparation method of the elastomer film is mainly based on a spraying process. Firstly, selecting a proper soluble high polymer material, preparing the material into a solution with a certain concentration, then spraying the solution on a temperature-controlled substrate by using an air-assisted spray gun to form a film, and volatilizing the solution to obtain the elastomer film with the multilayer surface microstructure. The current signal and the pressure of the flexible pressure sensor prepared by the film present a good linear relation in a range of 20000kPa, and the flexible pressure sensor can be used for monitoring the pulse of the radial artery.
In order to further illustrate the present invention, the following will describe in detail a method for manufacturing a micro-structured elastomer film and a method for manufacturing a flexible pressure sensor according to the present invention with reference to the following examples, which should not be construed as limiting the scope of the present invention.
Example 1
SEBS (styrene-ethylene-butylene-styrene) with the trademark of Karton G1650 is selected as a material and dissolved in Tetrahydrofuran (THF) to prepare a solution with the concentration of 20 mg/mL. The spray gun selects rock field powder 2-25W1G, the pressure of carrier gas is 0.25MPa, and the elastomer film with the thickness of about 200 mu m and the granular surface microstructure is obtained by spraying on a Polyimide (PI) film with the thickness of 100 mu m, and the granular structure has the appearance characteristics of small bottom and large top. Fig. 1 to 2 show an optical microscope image and a scanning electron microscope image thereof, respectively.
Example 2
The selected material is TPU, the mark number is Estane AlR MC 93A-V, and the TPU is dissolved in Tetrahydrofuran (THF) to prepare a solution with the concentration of 20 mg/mL. The spray gun selects a rock field wire 2-25W1G, the pressure of carrier gas is 0.25MPa, and the elastomer film with the thickness of about 100 mu m and the granular surface microstructure is obtained by spraying on a Polyimide (PI) film with the thickness of 100 mu m, and the appearance of the elastomer film is similar to that in the example 1. Such as fig. 3, is an optical microscope image thereof.
Example 3
SEBS (styrene-ethylene-butylene-styrene) with the trademark of Karton G1650 is selected as a material and dissolved in Tetrahydrofuran (THF) to prepare a solution with the concentration of 50 mg/mL. The spray gun selects rock field powder 2-25W1G, the pressure of carrier gas is 0.25MPa, and the elastomer film with the thickness of about 200 mu m and the mountain-shaped surface microstructure is obtained by spraying the elastomer film on a polyethylene terephthalate (PET) film with the thickness of 80 mu m. Fig. 4 to 5 show an optical microscope image and a scanning electron microscope image thereof, respectively.
Example 4
SEBS (styrene-ethylene-butylene-styrene) with the trademark of Karton G1652 is dissolved in Tetrahydrofuran (THF) to prepare 120mg/mL solution. The spray gun selects a rock field wire 2-25W1G, the pressure of carrier gas is 0.7MPa, and the elastomer film with the thickness of about 200 mu m and the wiredrawing surface microstructure is obtained by spraying on the PET film with the thickness of 80 mu m. Such as fig. 6, is a scanning electron microscope image thereof.
Example 5
The conductive ink was sprayed on the surface of the elastomer film prepared in example 1 using a pneumatic spray gun. Wherein the conductive ink is N, N-Dimethylformamide (DMF) dispersion liquid of multi-walled carbon nanotubes (MWCNTs), and the concentration is 2mg/mL; the spraying carrier gas pressure is 0.25MPa, and the thickness of the conductive layer obtained by spraying is 1-2 um. And (3) packaging the microstructure film with the conductive layer and the interdigital electrode in a combined manner (wherein the interdigital electrode is a PI substrate, the silver conductive layer has a working area of 2cm x 2cm, the total number of fingers is 20, and the finger gap width is 150 mu m) to obtain the flexible pressure sensor.
Example 6
Conductive ink was ultrasonically sprayed on the surface of the elastomer film prepared in example 3. Wherein the conductive ink is an N, N-Dimethylformamide (DMF) solution of multi-walled carbon nanotubes (MWCNTs), and the concentration is 5mg/mL; the carrier gas pressure of ultrasonic spraying is 0.4MPa, the ultrasonic power is 3.5W, the ink flow is 0.2mL/min, and the thickness of the conductive layer obtained by spraying is 1-2 um. And (3) packaging the microstructure film with the conductive layer and the interdigital electrode in a combined manner (wherein the interdigital electrode is a PI substrate, the silver conductive layer has a working area of 2cm x 2cm, the total number of fingers is 20, and the finger gap width is 150 mu m) to obtain the flexible pressure sensor.
Example 7
SEBS (styrene-ethylene-butylene-styrene) with the trademark of Karton G1650 is selected as a material and dissolved in Tetrahydrofuran (THF) to prepare a solution with the concentration of 80 mg/mL. The spray gun selects rock field powder 2-25W1G, the pressure of carrier gas is 0.25MPa, and the elastic film with the thickness of about 200 mu m and the wiredrawing surface microstructure is obtained by spraying on a PI film with the thickness of 100 mu m. And then spraying conductive ink on the surface of the film. The conductive ink is DMF dispersion liquid of MWCNTs, and the concentration is 2mg/mL; adopts a pneumatic auxiliary type spray gun, the pressure of carrier gas is 0.25MPa, and the thickness of the sprayed conductive layer is 1-2 um. And (3) packaging the microstructure film with the conductive layer and the interdigital electrode in a combined manner (wherein the interdigital electrode is a PI substrate, the silver conductive layer has a working area of 2cm x 2cm, the total number of fingers is 20, and the finger gap width is 150 mu m) to obtain the flexible pressure sensor.
The film with three morphologies of microstructure film was tested to form a sensor according to the method of example 5, and the result is shown in fig. 7, and it can be seen from fig. 7 that the broccoli-like microstructure obtained by spraying the low-concentration solution has the widest linear range, which is close to 20MPa.
The pressure sensor prepared in example 5 is used for testing human body pulse, and the testing process comprises the following steps: one side of the packaged sensor microstructure film is attached to the upper part of the radial artery of the wrist and is fixed by adhesive tape. The sensor is then powered through the source meter and test data is recorded. As shown in FIG. 8, it can be seen from FIG. 8 that the sensor of the present invention can clearly distinguish the pulse of the radial artery of the human body, and has potential applications.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A microstructure elastomer film comprises a substrate and a microstructure layer attached to the surface of a matrix;
the microstructure layer is provided with a granular microstructure which is small in the lower end part connected with the substrate, large in the upper end, rough in surface and fluffy in the interior; or a mountain-like microstructure which is connected with the substrate, has a large lower end part, a small upper end, a rough surface and a fluffy interior; or a fabric-like microstructure with interlaced fibers.
2. The production method according to claim 1, wherein the substrate is a polyethylene terephthalate film, a thermoplastic polyurethane elastomer film, a polyethylene film, a polypropylene film, or a polyimide film;
the thickness of the substrate is 50-100 μm.
3. The method of making a microstructured elastomeric film of claim 1, comprising the steps of:
a) Dissolving a thermoplastic elastomer material in a solvent to prepare an elastomer solution with the concentration of 10-120 mg/mL;
the thermoplastic elastomer material is one or more of hydrogenated styrene-butadiene block copolymer and thermoplastic polyurethane; the solvent is one or more of tetrahydrofuran, butyl acetate, 1, 4-dioxane, cyclohexanone and N, N-dimethylformamide;
b) And uniformly spraying the elastomer solution on the surface of a substrate, and removing the solvent to obtain the microstructure elastomer film.
4. The method of claim 3, wherein the elastomer solution is sprayed onto the surface of the substrate using an air-assisted spray gun; the carrier gas pressure of the spraying is 0.1-0.8 MPa; the diameter of the nozzle is 0.8-2.5 mm; the spraying distance is 20-50 cm.
5. A method according to claim 3, wherein the microstructured elastomeric film has a thickness of 50 to 300 μm.
6. The method according to claim 3, wherein the solvent is removed by heating or volatilization at room temperature.
7. A flexible pressure sensor comprising the microstructured elastomeric film of claim 1.
8. A preparation method of a flexible pressure sensor comprises the following steps:
1) Obtaining a microstructured elastomeric film according to the method of claim 1;
2) Forming a conductive layer on the surface of the micro-structure elastomer film to obtain a sensing film;
3) And combining and packaging one side of the conducting layer of the sensing film and the interdigital electrode to obtain the flexible pressure sensor.
9. The preparation method according to claim 8, wherein a conductive layer is formed by spraying a conductive ink on the surface of the microstructured elastomer film;
or forming a metal conducting layer on the surface of the microstructure elastomer film through magnetron sputtering or vacuum evaporation.
10. The method according to claim 9, wherein the conductive ink is an organic dispersion of a conductive carbon material; the thickness of the conductive layer is 1-2 μm.
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| CN202210951117.2A CN115290231A (en) | 2022-08-09 | 2022-08-09 | Microstructure elastomer film, preparation method thereof, flexible pressure sensor and preparation method thereof |
| PCT/CN2022/128150 WO2024031842A1 (en) | 2022-08-09 | 2022-10-28 | Microstructure elastomer film and preparation method therefor, and flexible pressure sensor and preparation method therefor |
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| CN202210951117.2A CN115290231A (en) | 2022-08-09 | 2022-08-09 | Microstructure elastomer film, preparation method thereof, flexible pressure sensor and preparation method thereof |
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| CN216284043U (en) * | 2021-10-22 | 2022-04-12 | 厦门大学 | High-linearity flexible pressure sensor with adjustable sensitivity |
| CN114370958B (en) * | 2022-01-13 | 2023-03-31 | 厦门大学 | High-performance capacitive flexible pressure sensor and preparation method thereof |
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| WO2024031842A1 (en) | 2024-02-15 |
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