CN113555494A - Flexible pressure sensor and preparation method thereof - Google Patents
Flexible pressure sensor and preparation method thereof Download PDFInfo
- Publication number
- CN113555494A CN113555494A CN202010262657.0A CN202010262657A CN113555494A CN 113555494 A CN113555494 A CN 113555494A CN 202010262657 A CN202010262657 A CN 202010262657A CN 113555494 A CN113555494 A CN 113555494A
- Authority
- CN
- China
- Prior art keywords
- thermoplastic polyurethane
- pressure sensor
- flexible pressure
- substrate
- carbon composite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000002360 preparation method Methods 0.000 title abstract description 5
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 41
- 239000002131 composite material Substances 0.000 claims abstract description 41
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 40
- 239000004416 thermosoftening plastic Substances 0.000 claims abstract description 40
- 239000000758 substrate Substances 0.000 claims abstract description 37
- 229920002803 thermoplastic polyurethane Polymers 0.000 claims abstract description 31
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 19
- 239000011651 chromium Substances 0.000 claims abstract description 19
- 239000011248 coating agent Substances 0.000 claims abstract description 19
- 238000000576 coating method Methods 0.000 claims abstract description 19
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 17
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 13
- 239000010936 titanium Substances 0.000 claims abstract description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 25
- 239000002041 carbon nanotube Substances 0.000 claims description 18
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 18
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 17
- 238000005187 foaming Methods 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 239000011521 glass Substances 0.000 claims description 6
- 229910021389 graphene Inorganic materials 0.000 claims description 6
- 238000004544 sputter deposition Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- 238000001704 evaporation Methods 0.000 claims description 4
- 230000008020 evaporation Effects 0.000 claims description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 239000010931 gold Substances 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 239000010949 copper Substances 0.000 claims description 2
- 239000007772 electrode material Substances 0.000 claims description 2
- 239000002064 nanoplatelet Substances 0.000 claims description 2
- 229920000747 poly(lactic acid) Polymers 0.000 claims description 2
- 229920000570 polyether Polymers 0.000 claims description 2
- 239000004626 polylactic acid Substances 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims description 2
- 239000010703 silicon Substances 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 239000004332 silver Substances 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 7
- 230000004044 response Effects 0.000 description 19
- 239000004433 Thermoplastic polyurethane Substances 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 239000003292 glue Substances 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- -1 polydimethylsiloxane, ethylene-vinyl acetate Polymers 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 208000008960 Diabetic foot Diseases 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 206010012601 diabetes mellitus Diseases 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002135 nanosheet Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000036285 pathological change Effects 0.000 description 1
- 231100000915 pathological change Toxicity 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920006124 polyolefin elastomer Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920003225 polyurethane elastomer Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 229920000468 styrene butadiene styrene block copolymer Polymers 0.000 description 1
- 238000004506 ultrasonic cleaning Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
- H10N30/302—Sensors
-
- 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
- G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/08—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of piezoelectric devices, i.e. electric circuits therefor
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/01—Manufacture or treatment
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/85—Piezoelectric or electrostrictive active materials
- H10N30/852—Composite materials, e.g. having 1-3 or 2-2 type connectivity
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Composite Materials (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention relates to a flexible pressure sensor and a preparation method thereof. The flexible pressure sensor includes a) a substrate; b) interdigitated electrodes attached to the substrate via a chromium or titanium coating; and c) a foamed thermoplastic polyurethane-carbon composite sheet on the interdigital electrodes, which comprises a thermoplastic polyurethane resin and an electrically conductive carbon material. The flexible pressure sensor has good flexibility, high elasticity and pressure-sensitive characteristics, and has good stability. Meanwhile, the flexible pressure sensor is simple in process and low in cost.
Description
Technical Field
The invention relates to the technical field of sensor manufacturing. In particular, the present invention relates to flexible pressure sensors and methods of making the same.
Background
The pressure sensor is a device which converts force signals into electric signals to be output by capturing the electrical property change of a sensitive material when the sensitive material is stressed. The application of the pressure sensor is deeply applied to many aspects of people's life, such as aerospace, national defense, military, water conservancy and hydropower, resource development, railway and marine transportation, medical diagnosis, electronic touch screens, electronic scales and the like.
At present, most pressure sensors are made of rigid sensitive materials such as metal and semiconductor strain gauges, and have the defects of high brittleness, small strain, lack of flexibility and poor comfort. However, the fields of human health, rehabilitation, physical exercise, and motion biology all have requirements for flexibility of sensors, for example, when the distribution of contact pressure between a diabetic foot of a diabetic patient and the ground is studied, the rigid sensor is difficult to be in complete contact with the sole of the foot of the diabetic patient, which makes it difficult to obtain the complete pathological change condition of the diabetic foot.
Therefore, it is necessary to make the pressure sensor flexible so as to be able to measure contact stress variations on a surface of a complex shape.
CN106370327A discloses a flexible pressure sensor, which includes two electrode structures oppositely disposed, each electrode structure includes a flexible substrate and a conductive layer disposed on the flexible substrate, the conductive layers of the two electrode structures are connected in contact toward each other; the flexible substrate comprises a substrate body and a plurality of convex structures arranged on the substrate body, and the conductive layer is arranged on the surface of the flexible substrate with the convex structures in a covering mode. The material of the flexible substrate is selected from any one of polydimethylsiloxane, ethylene-vinyl acetate copolymer, polyvinyl alcohol, styrene-butadiene-styrene block copolymer, aromatic random copolymer, styrene-butadiene rubber, polyurethane elastomer, polyolefin elastomer and polyamide elastomer.
However, many flexible materials have very little change in electrical properties under stress, resulting in a flexible pressure sensor made therefrom that is insensitive to pressure changes.
Accordingly, there remains a need in the art for a flexible pressure sensor that is sensitive to pressure changes.
Disclosure of Invention
It is an object of the present invention to provide a flexible pressure sensor which is sensitive to pressure variations.
Thus, according to a first aspect of the present invention, there is provided a flexible pressure sensor, characterized in that it comprises:
a) a substrate;
b) interdigitated electrodes attached to the substrate via a chromium or titanium coating; and
c) a foamed thermoplastic polyurethane-carbon composite sheet on the interdigital electrode, comprising a thermoplastic polyurethane resin and an electrically conductive carbon material.
According to a second aspect of the present invention, there is provided a method for manufacturing the above flexible pressure sensor, comprising the steps of:
I) applying a chromium or titanium coating on the substrate;
II) disposing the interdigitated electrodes on the chromium or titanium coating; and
III) affixing the foamed thermoplastic polyurethane-carbon composite sheet to the interdigitated electrodes to form the flexible pressure sensor.
The flexible pressure sensor has good flexibility, high elasticity and pressure-sensitive characteristics, and has good stability. Meanwhile, the flexible pressure sensor is simple in process and low in cost.
Drawings
The invention will be illustrated hereinafter with reference to the accompanying drawings, in which:
fig. 1 is a schematic structural view of a flexible pressure sensor according to an embodiment of the present invention, a: front view, b: a top view, wherein (r) represents a substrate; ② an interdigital electrode; and thirdly, showing the foamed thermoplastic polyurethane-carbon composite sheet.
Fig. 2 shows pressure-capacitance response curves of the flexible pressure sensors prepared in examples 1 to 5 and comparative example 1, where the ordinate Δ C is Cp-Co, Cp is capacitance at different compression ratios, and Co is capacitance when uncompressed.
Figure 3 shows the time-capacitance response curve of a flexible pressure sensor made in example 3 (with 5 wt% conductive carbon black added, relative to the weight of the thermoplastic polyurethane).
Figure 4 shows the time-capacitance response curve of the flexible pressure sensor prepared in example 5 (with 1 wt% carbon nanotubes added, relative to the weight of the thermoplastic polyurethane).
Detailed description of the preferred embodiments
Various aspects of the invention and still further objects, features and advantages will be more fully apparent hereinafter.
According to a first aspect of the present invention, there is provided a flexible pressure sensor, characterized in that it comprises:
a) a substrate;
b) interdigitated electrodes attached to the substrate via a chromium or titanium coating; and
c) a foamed thermoplastic polyurethane-carbon composite sheet on the interdigital electrode, comprising a thermoplastic polyurethane resin and an electrically conductive carbon material.
Fig. 1 is a schematic structural view of a flexible pressure sensor according to the present invention. As shown in fig. 1, r denotes a substrate; ② an interdigital electrode; and thirdly, showing the foamed thermoplastic polyurethane-carbon composite sheet. It should be understood that fig. 1 is merely illustrative and not intended to limit the present invention.
The substrate may be any substrate suitable for use in a sensor, and may be, for example, a glass substrate, a polylactic acid substrate, or a silicon substrate.
The interdigital electrodes are attached to the same surface of the substrate.
In order to allow the interdigital electrodes to be effectively attached to the substrate, the thickness of the chromium or titanium coating is preferably in the range of 2 to 10 nm.
Preferably, the electrode material of the interdigital electrode is selected from gold, copper, and silver.
Preferably, the thickness of the interdigital electrode is in the range of 20-100 nm.
Preferably, the width of each finger of the interdigital electrode is in the range of 10-100 μm, and the finger spacing is in the range of 10-100 μm.
In some embodiments, the interdigitated electrodes have a width of 100 μm per finger and a finger pitch of 50 μm.
In some embodiments, the thermoplastic polyurethane-carbon composite sheet is comprised of a thermoplastic polyurethane resin and a conductive carbon material.
Preferably, the thermoplastic polyurethane-carbon composite sheet has a foaming ratio of 3.5 to 5.
Preferably, the foamed thermoplastic polyurethane-carbon composite sheet has a hardness of 30A or less, preferably in the range of 10-30A, as determined according to ISO 868.
The thermoplastic polyurethane resin is not particularly limited and may be a thermoplastic polyurethane resin commonly used in the polyurethane field.
Preferably, the thermoplastic polyurethane resin is a Thermoplastic Polyurethane (TPU) resin suitable for supercritical foaming.
Preferably, the thermoplastic polyurethane resin has a hardness of 80A or less, preferably in the range of 60-80A, as determined according to ISO 868.
Preferably, the thermoplastic polyurethane is polyether-based.
Preferably, the conductive carbon material is selected from conductive carbon black, carbon nanotubes, graphene powder and graphene nanoplatelets, more preferably from conductive carbon black and carbon nanotubes, most preferably carbon nanotubes.
Preferably, the conductive carbon black has a particle size in the range of 10-50nm, such as 30-45 nm.
Preferably, the length of the carbon nanotubes is in the range of 0.5-30 μm, such as 3-15 μm.
Preferably, the graphene powder has a single layer rate of more than 80% and a thickness in the range of 0.1-2 nm.
Preferably, the conductivity of the graphene nano-sheet is within the range of 500-1000S/cm, and the thickness is within the range of 1-10 nm.
In some embodiments, the conductive carbon material is conductive carbon black in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the thermoplastic polyurethane.
In some embodiments, the conductive carbon material is carbon nanotubes in an amount of 0.5 to 1 parts by weight based on 100 parts by weight of the thermoplastic polyurethane.
In the foamed thermoplastic polyurethane-carbon composite sheet, the thermoplastic polyurethane is physically bonded to the conductive carbon material.
The foamed thermoplastic polyurethane-carbon composite sheet may have any thickness or shape.
Preferably, the thickness of the foamed thermoplastic polyurethane-carbon composite sheet is in the range of 6 to 12 mm.
Preferably, the foamed thermoplastic polyurethane-carbon composite sheet has a density of 210-410kg/m3Within the range.
According to a second aspect of the present invention, there is provided a method for manufacturing the above flexible pressure sensor, comprising the steps of:
I) applying a chromium or titanium coating on the substrate;
II) disposing the interdigitated electrodes on the chromium or titanium coating; and
III) affixing the foamed thermoplastic polyurethane-carbon composite sheet to the interdigitated electrodes to form the flexible pressure sensor.
The chromium or titanium coating may be applied to the substrate by methods such as evaporation, sputtering (including dc sputtering and magnetron sputtering), and the like.
The interdigitated electrodes may also be disposed on the chromium coating by methods such as evaporation, sputtering (including dc sputtering and magnetron sputtering), and the like.
The foamed thermoplastic polyurethane-carbon composite sheet may be fixed on the interdigitated electrodes by a method known in the art of electronic devices (with a glue, such as a polypropylene glue).
In some embodiments, the method of making further comprises the step of providing the foamed thermoplastic polyurethane-carbon composite sheet described above.
Providing the foamed thermoplastic polyurethane-carbon composite sheet described above can be carried out by:
1) mixing a conductive carbon material with a thermoplastic polyurethane resin to obtain a mixture;
2) processing the mixture into thermoplastic polyurethane-carbon composite chips; and
3) foaming the thermoplastic polyurethane-carbon composite chips to obtain a foamed thermoplastic polyurethane-carbon composite sheet.
Those skilled in the art can readily mix and process the conductive carbon material with the thermoplastic polyurethane by blending processes known in the art (e.g., by single screw extrusion) into thermoplastic polyurethane-carbon composite chips, e.g., in the form of particles, short sheets, or other useful forms.
Also, those skilled in the art can easily prepare a foamed thermoplastic polyurethane-carbon composite sheet by a foaming process known in the art (e.g., a supercritical foaming process).
Preferably, the thermoplastic polyurethane-carbon composite chips are foamed at a foaming ratio of 3.5 to 5 in the above step 3.
The resulting foamed thermoplastic polyurethane-carbon composite sheet has a hardness of 30A or less, preferably in the range of 10-30A, as determined according to ISO 868.
The terms "comprising" and "including" as used herein encompass the case where other elements not explicitly mentioned are also included or included and the case where they consist of the mentioned elements.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the event that a definition of a term in this specification conflicts with a meaning commonly understood by those skilled in the art to which the invention pertains, the definition set forth herein shall govern.
Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that can vary depending upon the desired properties to be obtained.
Examples
The concept and technical effects of the present invention will be further described with reference to the following examples so that those skilled in the art can fully understand the objects, features and effects of the present invention. It should be understood that the examples are illustrative only and are not intended to limit the scope of the present invention.
The materials used
Thermoplastic polyurethane: from COVESTRO Inc
9380AU DPS650；
Conductive carbon black: XF115 from XFNANO, 30-45 nm;
carbon nanotube: XFQ039 from XFNANO corporation, 3-15 μm in length.
Pressure-capacitance response curve test
The pressure-capacitance response curve under applied pressure was tested by connecting the two electrodes of a flexible piezoelectric transducer to a co-existing LCR TH2827C digital bridge via wires. The application of pressure was performed by a mechanical testing machine, and the change in capacitance with pressure was measured.
Time-capacitance response curve
Both electrodes of the flexible piezoelectric transducer were wired to a co-existing LCR TH2827C digital bridge, and the pressure application and removal processes were cycled to test the time-capacitance response curves.
Example 1
Preparation of foamed thermoplastic polyurethane-carbon composite sheet
100 parts by weight of thermoplastic polyurethane and 0.5 part by weight of conductive carbon black are premixed and extruded by a single screw extruder to obtain the thermoplastic polyurethane-carbon composite slice, wherein the barrel temperature of the single screw extruder is 170-200 ℃, and the rotating speed is 50-90 RPM.
Foaming the obtained thermoplastic polyurethane-carbon composite slice for 60 minutes at the temperature of 120 ℃ and under the pressure of 12mpa by adopting supercritical foaming equipment to obtain a foamed thermoplastic polyurethane-carbon composite sheet, wherein the foaming ratio is 5, and the thickness is 5 mm.
Preparation of flexible pressure sensor
And (2) placing the glass substrate in an acetone and isopropanol solution for ultrasonic cleaning, then washing with deionized water and ethanol, then drying with nitrogen, and placing in an oven for drying.
The glass substrate was covered with a mask and placed in a vacuum evaporator to evaporate a chromium coating having a thickness of about 5nm on the glass substrate.
The glass substrate with the chromium coating was covered with a mask and placed in a vacuum evaporator to evaporate gold interdigitated electrodes with a thickness of about 50nm on the chromium coating, wherein the width of each finger was 100 μm and the finger spacing was 50 μm.
The foamed thermoplastic polyurethane-carbon composite sheet was fixed on the interdigitated electrodes with polypropylene glue, resulting in a flexible pressure sensor 1 within the scope of the present invention.
Example 2
Example 2 was conducted with reference to example 1, except that 1 part by weight of conductive carbon black was used, to obtain a flexible pressure sensor 2 within the scope of the present invention.
Example 3
Example 3 was conducted with reference to example 1, except that 5 parts by weight of conductive carbon black was used, to obtain a flexible pressure sensor 3 within the scope of the present invention.
Example 4
Example 4 was conducted with reference to example 1, except that 0.5 parts by weight of carbon nanotubes was used, to obtain a flexible pressure sensor 4 within the scope of the present invention.
Example 5
Example 5 was conducted with reference to example 1, except that 1 part by weight of carbon nanotubes was used, to obtain a flexible pressure sensor 5 within the scope of the present invention.
Comparative example 1
Comparative example 1 was conducted with reference to example 1, except that a foamed thermoplastic polyurethane sheet was prepared using pure thermoplastic polyurethane instead of the foamed thermoplastic polyurethane-carbon composite sheet without using a conductive carbon material, to obtain a comparative flexible pressure sensor 1 which was out of the scope of the present invention.
Example 6
The flexible pressure sensors prepared in examples 1 to 5 and comparative example 1 were subjected to a pressure-capacitance response curve test.
Fig. 2 shows pressure-capacitance response curves of the flexible pressure sensors prepared in examples 1 to 5 and comparative example 1, in which the ordinate represents the difference between the capacitance under applied pressure and the initial capacitance, and the abscissa represents the pressure value.
As can be seen from the pressure-capacitance response curve of fig. 2, the flexible pressure sensor prepared in comparative example 1 showed almost no change in capacitance when compressed.
It can also be seen from the pressure-capacitance response curves of fig. 2 that the flexible pressure sensors prepared in examples 1 to 5 have high sensitivity response characteristics compared to the flexible pressure sensor prepared in comparative example 1. The larger the doping ratio of the conductive carbon material, the larger the change in capacitance with pressure. When pressure is applied to create elastic deformation, the capacitance will gradually increase, and when the pressure is removed, the capacitance will return to its original value.
It can also be seen from the pressure-capacitance response curve of fig. 2 that even though the proportion of carbon nanotubes is lower than the proportion of conductive carbon black, the flexible pressure sensor with carbon nanotubes has a stronger piezoelectric response than the flexible pressure sensor with conductive carbon black.
Example 7
The flexible pressure sensors prepared in examples 3 and 5 were subjected to a time-capacitance response curve test.
The time-capacitance response curve of the foamed TPU carbon composite was tested by cycling the applied and removed pressure through an LCR precision digital bridge as the sample was compressed from 10mm to 4mm or 6 mm.
Figure 3 shows the time-capacitance response curve of a flexible pressure sensor made in example 3 (with 5 wt% conductive carbon black added, relative to the weight of the thermoplastic polyurethane).
Figure 4 shows the time-capacitance response curve of the flexible pressure sensor prepared in example 5 (with 1 wt% carbon nanotubes added, relative to the weight of the thermoplastic polyurethane).
As can be seen from fig. 3 and 4, the capacitance increases with increasing pressure, returns to the original value with decreasing pressure, and maintains good stability after a certain number of cycles.
It can also be seen from fig. 3 and 4 that the flexible pressure sensor with carbon nanotubes has a more stable piezoelectric response than the flexible pressure sensor with conductive carbon black.
Although a few aspects of the present invention have been shown and discussed, it would be appreciated by those skilled in the art that changes may be made in this aspect without departing from the principles and spirit of the invention, the scope of which is therefore defined in the claims and their equivalents.
Claims (17)
1. A flexible pressure sensor, comprising:
a) a substrate;
b) interdigitated electrodes attached to the substrate via a chromium or titanium coating; and
c) a foamed thermoplastic polyurethane-carbon composite sheet on the interdigital electrode, comprising a thermoplastic polyurethane resin and an electrically conductive carbon material.
2. The flexible pressure sensor of claim 1, wherein the substrate is selected from a glass substrate, a polylactic acid substrate, and a silicon substrate.
3. A flexible pressure sensor according to claim 1 or 2, characterized in that the thickness of the chromium or titanium coating is in the range of 2-10 nm.
4. The flexible pressure sensor according to any of claims 1-3, wherein the electrode material of the interdigitated electrodes is selected from gold, copper and silver.
5. The flexible pressure sensor according to any of claims 1-4, wherein the interdigitated electrodes have a thickness in the range of 20-100 nm.
6. The flexible pressure sensor of any of claims 1-5, wherein the foamed thermoplastic polyurethane-carbon composite sheet is comprised of a thermoplastic polyurethane resin and a conductive carbon material.
7. The flexible pressure sensor of any of claims 1-6, wherein the foamed thermoplastic polyurethane-carbon composite sheet has a foaming ratio of 3.5 to 5.
8. The flexible pressure sensor according to any of claims 1-7, wherein the foamed thermoplastic polyurethane-carbon composite sheet has a hardness of 30A or less, preferably in the range of 10-30A, determined according to ISO 868.
9. The flexible pressure sensor of any of claims 1-8, wherein the thermoplastic polyurethane resin is polyether based.
10. The flexible pressure sensor according to any of claims 1-9, wherein the conductive carbon material is selected from the group consisting of conductive carbon black, carbon nanotubes, graphene powder and graphene nanoplatelets, preferably from the group consisting of conductive carbon black and carbon nanotubes, more preferably carbon nanotubes.
11. A flexible pressure sensor according to any of claims 1-10, characterized in that the conductive carbon material is conductive carbon black in an amount of 0.5-5 parts by weight based on 100 parts by weight of thermoplastic polyurethane resin, preferably the particle size of the conductive carbon black is in the range of 10-50nm, such as 30-45 nm.
12. A flexible pressure sensor according to any of claims 1-10, characterized in that the electrically conductive carbon material is carbon nanotubes in an amount of 0.5-1 parts by weight based on 100 parts by weight of thermoplastic polyurethane resin, preferably the length of the carbon nanotubes is in the range of 0.5-30 μ ι η, such as 3-15 μ ι η.
13. Method for manufacturing a flexible pressure sensor according to any of claims 1-12, characterized in that it comprises the following steps:
I) applying a chromium or titanium coating on the substrate;
II) disposing the interdigitated electrodes on the chromium coating; and
III) affixing the foamed thermoplastic polyurethane-carbon composite sheet to the interdigitated electrodes to form the flexible pressure sensor.
14. The method of claim 13, wherein the preparing of the foamed thermoplastic polyurethane-carbon composite sheet comprises the steps of:
1) mixing a conductive carbon material and a thermoplastic polyurethane resin to obtain a mixture;
2) processing the mixture into thermoplastic polyurethane-carbon composite chips; and
3) the thermoplastic polyurethane-carbon composite chips are foamed to obtain foamed thermoplastic polyurethane-carbon composite sheets.
15. The method according to claim 14, wherein the thermoplastic polyurethane-carbon composite chip is foamed at a foaming ratio of 3.5 to 5 in step 3.
16. A method of production according to any one of claims 13 to 15, characterised in that the chromium or titanium coating is applied to the substrate by evaporation or sputtering.
17. A method of manufacturing as claimed in any one of claims 13 to 16, characterized in that the interdigitated electrodes are provided on the chromium coating by evaporation or sputtering.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010262657.0A CN113555494A (en) | 2020-04-03 | 2020-04-03 | Flexible pressure sensor and preparation method thereof |
| PCT/EP2021/058076 WO2021198133A1 (en) | 2020-04-03 | 2021-03-29 | Flexible pressure sensor and method for preparing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010262657.0A CN113555494A (en) | 2020-04-03 | 2020-04-03 | Flexible pressure sensor and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113555494A true CN113555494A (en) | 2021-10-26 |
Family
ID=78100875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010262657.0A Pending CN113555494A (en) | 2020-04-03 | 2020-04-03 | Flexible pressure sensor and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113555494A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113776702A (en) * | 2021-11-15 | 2021-12-10 | 北京石墨烯技术研究院有限公司 | Flexible pressure sensor, preparation method thereof and wearable device |
-
2020
- 2020-04-03 CN CN202010262657.0A patent/CN113555494A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113776702A (en) * | 2021-11-15 | 2021-12-10 | 北京石墨烯技术研究院有限公司 | Flexible pressure sensor, preparation method thereof and wearable device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Xu et al. | Wearable CNT/Ti3C2T x MXene/PDMS composite strain sensor with enhanced stability for real-time human healthcare monitoring | |
| WO2021198133A1 (en) | Flexible pressure sensor and method for preparing the same | |
| Huang et al. | Three-dimensional light-weight piezoresistive sensors based on conductive polyurethane sponges coated with hybrid CNT/CB nanoparticles | |
| Mai et al. | Ultra-stretchable MWCNT–Ecoflex piezoresistive sensors for human motion detection applications | |
| Wu et al. | Strategies for designing stretchable strain sensors and conductors | |
| White et al. | Low‐Cost, facile, and scalable manufacturing of capacitive sensors for soft systems | |
| Tolvanen et al. | Hybrid foam pressure sensor utilizing piezoresistive and capacitive sensing mechanisms | |
| CN102002252B (en) | Micro-deformable piezoresistive material and manufacturing method thereof | |
| Tai et al. | Flexible pressure sensing film based on ultra-sensitive SWCNT/PDMS spheres for monitoring human pulse signals | |
| CN112284577B (en) | Piezoelectric piezoresistive composite touch sensor and preparation method thereof | |
| Hu et al. | Recent progress in flexible micro-pressure sensors for wearable health monitoring | |
| Meena et al. | Highly stretchable and robust textile-based capacitive mechanical sensor for human motion detection | |
| CN112326074B (en) | Touch sensor, preparation method and intelligent device comprising touch sensor | |
| CN110057476B (en) | Multi-signal response flexible electronic skin and preparation method thereof | |
| CN109883582A (en) | A kind of flexible capacitive sensor based on conductive rubber | |
| CN113555494A (en) | Flexible pressure sensor and preparation method thereof | |
| Seesaard et al. | Fabric-based piezoresistive Ti3AlC2/PEDOT: PSS force sensor for wearable E-textile applications | |
| Yao et al. | Poly (vinyl alcohol)/phosphoric acid gel electrolyte@ polydimethylsiloxane sponge for piezoresistive pressure sensors | |
| Baloda et al. | A flexible pressure sensor based on multiwalled carbon nanotubes/polydimethylosiloxane composite for wearable electronic-skin application | |
| CN110816008A (en) | Elastomer and method for producing same | |
| Liu et al. | A versatile surface micro structure design strategy for porous-based pressure sensors to enhance electromechanical performance | |
| Momin et al. | Development of compact load cell using multiwall carbon nanotube/cotton composites and its application to human health and activity monitoring | |
| Karagiorgis et al. | 3D-printed elastomer foam-based soft capacitive pressure sensors | |
| CN113514176A (en) | Low-temperature stretchable flexible stress sensor based on 3D printing and preparation method | |
| Amjadi et al. | Flexible and sensitive foot pad for sole distributed force detection |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |