Flexible self-driven pressure sensor and preparation method thereof

Abstract

The present invention provides a flexible self-driven pressure sensor and a preparation method thereof, relating to the technical field of flexible sensors. The pressure sensor includes a bottom packaging portion, a triboelectric pressure sensing portion, and a top packaging portion stacked in sequence; the triboelectric pressure sensing portion includes a stacked MXene-based silicone layer and a pressure friction layer; a plurality of MXene-based silicone microstructure blocks and a plurality of MXene-based isolation walls are formed on the side of the MXene-based silicone layer close to the pressure friction layer, the other ends of the plurality of MXene-based isolation walls are in contact with the pressure friction layer, and the plurality of MXene-based silicone microstructure blocks are located between the MXene-based silicone layer and the pressure friction layer; the side of the MXene-based silicone microstructure block close to the pressure friction layer is pointed. The pressure sensor provided by the present invention can detect relatively low pressures, has good stability and fast response speed, does not require external power input, and has a simple process and strong repeatability. It has good application prospects in flexible wearable electronics, biomedicine, and intelligent soft robots.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible sensors, and in particular to a flexible self-driven pressure sensor and a preparation method thereof. Background Art

[0002] In recent years, electronic skin that mimics the functional properties of human skin has become a research hotspot. Tactile sensors, in particular, that sense pressure or strain, can efficiently convert mechanical stimuli into electrical signals, and have important application prospects in fields such as human-computer interaction, intelligent robotics, and biomedicine. Traditional silicon-based MEMS capacitors and resistive pressure sensors are not only incompatible with curved surfaces, but their passive nature also requires a certain amount of energy, which conflicts with the concept of carbon neutrality.

[0003] The friction effect refers to the transfer of charge at the interface when two dissimilar materials come into contact and separate under external forces. The coupling of triboelectric charging and electrostatic induction results in a flow of charge at the back electrode. Therefore, a tactile sensor based on the friction effect can not only act as an energy harvester, converting mechanical energy generated by the surrounding environment into stored electrical energy, but can also function as a self-actuated tactile sensor based on the generated electrical signals.

[0004] The prior art discloses a method for preparing an Alk-Ti3C2 / PDMS flexible piezoresistive sensor, which comprises covering a silica gel mixture on an emery cloth with a raised structure to obtain a first PDMS film, covering the first PDMS film with perfluorosilicone, then covering it with a layer of silica gel mixture and curing it to obtain a second PDMS film, and then covering the second PDMS film with Alk-Ti3C2.

[0005] However, the surface morphology of flexible piezoresistive sensors provided by existing technologies is irregular, resulting in poor device consistency and repeatability. Furthermore, traditional flexible resistive and capacitive pressure sensors require external power input to operate, which significantly limits their use cases and service life. Therefore, a solution is urgently needed to address these issues. Summary of the Invention

[0006] The purpose of the present invention is to provide a flexible self-driven pressure sensor and its preparation method, which can detect relatively low pressure, has good stability and fast response speed, does not require external power input, and has simple process and strong repeatability. It has good application prospects in flexible wearable electronics, biomedicine and intelligent soft robots.

[0007] In a first aspect, the present invention provides a flexible self-driven pressure sensor, which adopts the following technical solution:

[0008] It includes a bottom packaging part, a friction electric pressure sensing part and a top packaging part which are stacked in sequence from bottom to top;

[0009] The triboelectric pressure sensing portion includes a stacked MXene-based silicone layer and a pressure friction layer;

[0010] A plurality of MXene-based silica gel microstructure blocks and a plurality of MXene-based isolation walls are integrally formed on a side of the MXene-based silica gel layer close to the pressure friction layer, wherein one end of the plurality of MXene-based isolation walls relatively far from the MXene-based silica gel layer contacts the pressure friction layer, and the plurality of MXene-based silica gel microstructure blocks are located between the MXene-based silica gel layer and the pressure friction layer;

[0011] The MXene-based silica gel microstructure block is arranged with a pointed end on a side close to the pressure friction layer;

[0012] The MXene is a material with a two-dimensional structure formed by removing the main group elements from the MAX phase;

[0013] The MAX phase is M n+1 AX n , wherein n is equal to any one of 1, 2 and 3, the M is a transition metal element, the A is a main group element, and the X is a carbon element or a nitrogen element.

[0014] The beneficial effects of the flexible self-driven pressure sensor provided by the present invention are: the friction electric pressure sensing part causes the pressure friction layer and the MXene-based silicone layer to rub against each other through pressure, thereby generating charge transfer at the contact interface between the pressure friction layer and the MXene-based silicone layer, and transmitting the electrical signal to the outside through the bottom packaging part and the top packaging part, thereby eliminating the need for external power input; the multiple MXene-based silicone microstructure blocks on the MXene-based silicone layer are arranged with pointed ends close to the pressure friction layer, so when the MXene-based silicone microstructure blocks come into contact with the pressure friction layer, the rate of change of the contact area between the MXene-based silicone microstructure blocks and the pressure friction layer increases, effectively improving the sensitivity of the friction electric pressure sensing part to pressure detection, so that the friction electric pressure sensing part can detect tiny pressure changes; and the pressure sensor provided by the present invention does not require an additional power supply, can achieve low power consumption and miniaturization of the device, has a stable structure, and is easy to array, and has broad application prospects in wearable electronics, intelligent robots and flexible devices.

[0015] Optionally, a plurality of MXene-based silica gel microstructure block arrays are arranged on the MXene-based silica gel layer.

[0016] Optionally, the first dimension of the plurality of MXene-based silica gel microstructure blocks decreases sequentially from the center of the array to the periphery of the array; the first dimension is the vertical distance between the end of the MXene-based silica gel microstructure block and the MXene-based silica gel layer.

[0017] Optionally, the first dimensions of the plurality of MXene-based silica gel microstructure blocks are all equal; the first dimension is the vertical distance between the end of the MXene-based silica gel microstructure block and the MXene-based silica gel layer.

[0018] In a second aspect, the present invention provides a method for preparing a flexible self-driven pressure sensor, which adopts the following technical solution and includes the following steps:

[0019] preparing a microstructured resin template;

[0020] preparing a MXene-based silica gel mixture;

[0021] Covering the MXene-based silica gel mixture on the microstructured resin template, and peeling off after curing to obtain a MXene-based silica gel layer;

[0022] The MXene-based silicone layer and the pressure friction layer are assembled to obtain a triboelectric pressure sensing portion;

[0023] The friction electric pressure sensing portion is assembled with the bottom packaging portion and the top packaging portion.

[0024] The beneficial effects of the preparation method of the flexible self-driven pressure sensor provided by the present invention are: a microstructured resin template is prepared in advance, and the microstructured resin template can be adjusted according to the required structural morphology of the MXene-based silicone layer, thereby improving the customizability of the MXene-based silicone layer and being able to be used for batch preparation and production with strong repeatability.

[0025] Optionally, the step of preparing a MXene-based silica gel mixture includes the following steps: preparing MXene powder; and uniformly mixing the MXene powder with a silica gel matrix to produce a MXene-based silica gel mixture; wherein the MXene powder accounts for 2% to 10% by weight of the silica gel matrix. After mixing the MXene powder with the silica gel matrix, the MXene powder is uniformly mixed in the silica gel matrix, thereby enhancing the friction effect and thus improving the basic performance of the pressure sensor.

[0026] Optionally, the MXene powder is Ti3C2F2 powder. MXene containing F groups has better electronegativity, which can effectively improve the output of the triboelectric pressure sensor and increase the sensitivity of the triboelectric pressure sensor to pressure.

[0027] Optionally, the step of preparing MXene powder includes adding a Ti3AlC2-MAX precursor to a 1-3M hydrofluoric acid solution for a reaction of 10-20 minutes, filtering, drying, and grinding to obtain MXene powder. Adding the Ti3AlC2-MAX precursor to a low-concentration HF solution can improve safety during production and improve the electronegativity of the prepared F-group-containing MXene, which can effectively improve the output of the triboelectric pressure sensor and increase the sensitivity of the triboelectric pressure sensor to pressure.

[0028] Optionally, the step of covering the microstructured resin template with the MXene-based silica gel mixture and peeling off the MXene-based silica gel layer after curing includes: covering the microstructured resin template with the MXene-based silica gel mixture, placing it in a vacuum environment, letting it stand for 25-35 minutes, and then drying and curing it to peel off the MXene-based silica gel layer. After the MXene-based silica gel mixture is covered on the microstructured resin template, the gas between the MXene-based silica gel mixture and the microstructured resin template can be removed in a vacuum environment, so that the MXene-based silica gel mixture and the microstructured resin template are fully adhered. After the MXene-based silica gel mixture is cured to obtain the MXene-based silica gel layer, the microstructure on the microstructured resin template is formed on the MXene-based silica gel layer.

[0029] Optionally, the ratio of the mass of the MXene-based silica gel mixture to the surface area of ​​the microstructured resin template is 0.1 g / cm 2 -0.3g / cm 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 1 is a schematic structural diagram of a flexible self-driven pressure sensor according to an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the structure of the MXene-based silica gel microstructure block in an embodiment of the present invention;

[0032] Figure 3 is a side view highlighting the MXene-based silica gel microstructure block in an embodiment of the present invention;

[0033] Figure 4 is a top view highlighting the MXene-based silica gel microstructure block in an embodiment of the present invention;

[0034] Figure 5 is a response time curve diagram of the flexible self-actuated pressure sensor under loading pressure and unloading pressure in Example 2 of the present invention;

[0035] Figure 61 is a graph showing voltage outputs of the flexible self-actuated pressure sensor at pressures of 0.11 KPa, 0.65 KPa, 1.50 KPa, 4.30 KPa, 6.80 KPa, 10.50 KPa, 19.00 KPa, and 50.00 KPa in Example 2 of the present invention;

[0036] Figure 7 is a flow chart of a method for preparing a flexible self-driven pressure sensor according to an embodiment of the present invention;

[0037] Figure 8 This is a specific flow chart of S1 in a method for preparing a flexible self-driven pressure sensor according to an embodiment of the present invention;

[0038] Figure 9 This is a specific flow chart of S2 in a method for preparing a flexible self-driven pressure sensor according to an embodiment of the present invention;

[0039] Figure 10 This is a specific flow chart of S21 in a method for preparing a flexible self-driven pressure sensor in an embodiment of the present invention.

[0040] Description of reference numerals:

[0041] 1. Bottom packaging part; 11. Bottom flexible electrode layer; 12. Bottom packaging layer; 13. Bottom electrode wire; 2. Triboelectric pressure sensing part; 21. MXene-based silicone layer; 22. Pressure friction layer; 3. Top packaging part; 31. Top flexible electrode layer; 32. Top packaging layer; 33. Top electrode wire; 4. MXene-based silicone microstructure block; 5. MXene-based isolation wall; 6. First direction; 7. Second direction; 8. Third direction; 9. First structural ring; 14. Second structural ring; 15. Third structural ring. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the invention belongs. The words "including" and similar words used in this article mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0043] MXene material is a graphene-like structure obtained by MAX phase treatment. The specific molecular formula of MAX is Mn+1 AX n (n = 1, 2, 3), where M refers to a transition metal from the first few groups, A refers to a main group element, and X refers to carbon and / or nitrogen. Because MX has strong bonding energy and A is chemically active, removing A from the MAX phase can yield a graphene-like two-dimensional structure. Since the initial synthesis of MXene materials, significant progress has been made in their applications in energy storage, electromagnetic interference shielding, transparent conductive electrodes, and field-effect transistors. Furthermore, the fundamental property of MXene, where the interlayer spacing changes significantly under external forces, has enabled the fabrication of piezoresistive sensors.

[0044] An embodiment of the present invention provides a flexible self-driven pressure sensor.

[0045] See also Figure 1 The flexible self-driven pressure sensor includes a bottom packaging part 1, a friction electric pressure sensing part 2 and a top packaging part 3 stacked from bottom to top. The friction electric pressure sensing part 2 senses pressure and converts it into an electrical signal, which is output through the bottom packaging part 1 and the top packaging part 3.

[0046] In some embodiments, see Figure 1 The bottom packaging part 1 includes a bottom flexible electrode layer 11 and a bottom packaging layer 12, wherein the bottom flexible electrode layer 11 is located at the bottom of the friction electric pressure sensing part 2, the bottom packaging layer 12 is located at the bottom of the bottom flexible electrode layer 11, and the bottom packaging part 1 also includes a bottom electrode wire 13, which is electrically connected to the bottom flexible electrode layer 11.

[0047] In some embodiments, the bottom flexible electrode layer 11 is made of flexible conductive materials such as silver nanofibers, carbon nanotubes, conductive silver paste, and conductive tape.

[0048] In some embodiments, the bottom encapsulation layer 12 is a silicone layer formed by curing pure silicone.

[0049] In some embodiments, see Figure 1 The top packaging part 3 includes a top flexible electrode layer 31 and a top packaging layer 32, wherein the top flexible electrode layer 31 is located on the top of the friction electric pressure sensing part 2, and the top packaging layer 32 is located on the top of the top flexible electrode layer 31, and the top packaging part 3 also includes a top electrode wire 33, which is electrically connected to the top flexible electrode layer 31, so that the electrical signal generated by the friction electric pressure sensing part 2 is output through the top electrode wire 33 and the bottom electrode wire 13.

[0050] In some embodiments, the top flexible electrode layer 31 is made of flexible conductive materials such as silver nanofibers, carbon nanotubes, conductive silver paste, and conductive tape.

[0051] In some embodiments, the top encapsulation layer 32 is a silicone layer formed by curing pure silicone.

[0052] See also Figure 1 The triboelectric pressure sensing unit 2 includes a stacked MXene-based silicone layer 21 and a pressure friction layer 22. The friction between the MXene-based silicone layer 21 and the pressure friction layer 22 generates an electrical signal. Multiple MXene-based silicone microstructure blocks 4 and multiple MXene-based isolation walls 5 are integrally formed on the side of the MXene-based silicone layer 21 near the pressure friction layer 22. The multiple MXene-based isolation walls 5 are located around the sidewalls of the MXene-based silicone layer 21, and the other ends of the multiple MXene-based isolation walls 5 are in contact with the pressure friction layer 22. The multiple MXene-based silicone microstructure blocks 4 are located between the MXene-based silicone layer 21 and the pressure friction layer 22.

[0053] In some embodiments, the MXene-based silica gel layer 21 , the MXene-based silica gel microstructure block 4 and the MXene-based isolation wall 5 are all integrally cast using a template.

[0054] In some embodiments, the MXene-based silica gel layer 21 , the MXene-based silica gel microstructure blocks 4 and the MXene-based isolation walls 5 are made of the same material and all contain MXene material.

[0055] In some embodiments, the MXene material contained in the MXene-based silica gel layer 21 , the MXene-based silica gel microstructure blocks 4 and the MXene-based isolation walls 5 is Ti 3 C 2 F 2 powder.

[0056] In some embodiments, the length and width of the MXene-based isolation wall 5 on the MXene-based silica gel layer 21 are both 1 mm, and the height of the MXene-based isolation wall 5 is 0.9 mm-1.1 mm.

[0057] In some embodiments, the MXene-based isolation wall 5 is L-shaped.

[0058] In some embodiments, the thickness of the MXene-based silica gel layer 21 is 30-100 μm.

[0059] In some embodiments, the height of the MXene-based isolation wall 5 is such that when the pressure friction layer 22 collides with the MXene-based isolation wall 5 , the pressure friction layer 22 collides with at least one MXene-based silica gel microstructure block 4 .

[0060] In some embodiments, the pressure friction layer 22 is a nylon film. The nylon film has a strong triboelectric positive property, which is conducive to the triboelectric effect with the MXene-based silicone layer 21.

[0061] In some embodiments, the pressure friction layer 22 has a thickness of 30-50 μm.

[0062] See also Figure 1 The MXene-based silica microstructure block 4 is set at a pointed end on the side close to the pressure friction layer 22. When the pressure friction layer 22 rubs against the MXene-based silica microstructure block 4 due to external pressure to generate charge movement, it has better response speed and sensitivity.

[0063] In some embodiments, see Figure 2 The first direction 6 is the direction in which the MXene-based silica gel microstructure block 4 is perpendicular to the MXene-based silica gel layer 21. The second direction 7 and the third direction 8 are two mutually perpendicular directions of the MXene-based silica gel microstructure block 4 on the upper edge of the MXene-based silica gel layer 21. The MXene-based silica gel microstructure block 4 is in the shape of a quadrangular prism, and the sizes of the MXene-based silica gel microstructure block 4 in the first direction 6, the second direction 7 and the third direction 8 are the first size, the second size and the third size, respectively.

[0064] In some embodiments, the first size of the MXene-based silica gel microstructure block 4 is 500-1200 μm.

[0065] In some embodiments, the first size and the second size of the MXene-based silica microstructure block 4 are independently 0.6 mm to 1.2 mm.

[0066] In some embodiments, the ratio of the first size, the second size, and the third size of the MXene-based silica gel microstructure block 4 is 1:1:(1-2).

[0067] In some embodiments, the MXene-based silica microstructure block 4 is conical or polygonal.

[0068] In some embodiments, see Figure 3 and Figure 4A plurality of MXene-based silica microstructure blocks 4 are arranged in an array on a MXene-based silica layer 21 in a 7×7 square array. The MXene-based silica microstructure blocks 4 are arranged on the MXene-based silica layer 21 in a 7×7 square array. The MXene-based silica microstructure blocks 4 are centered on the center of the array on the MXene-based silica layer 21. Three nested MXene-based silica rings are formed around the central MXene-based silica microstructure block 4. The MXene-based silica rings closer to the central MXene-based silica microstructure block 4 and farther from the central MXene-based silica microstructure block 4 are, in order, a first structure ring 9, a second structure ring 14, and a third structure ring 15. The first dimensions of the MXene-based silica microstructure blocks 4 in the first structure ring 9, the second structure ring 14, and the third structure ring 15 decrease in size, and the first dimensions of the MXene-based silica microstructure blocks 4 in the first structure ring 9 are smaller than those of the central MXene-based silica microstructure block 4.

[0069] Therefore, it will be Figure 3 and Figure 4 The performance curve of the flexible self-actuated pressure sensor after performance testing is shown in FIG. Figure 5 and Figure 6 As shown. Among them, Figure 5 The horizontal axis is time in seconds, and the vertical axis is voltage in volts; Figure 6 The horizontal axis is time in seconds, and the vertical axis is voltage in volts.

[0070] See also Figure 5 When the flexible self-driven pressure sensor is loaded with pressure, the response time of the pressure sensor is 21ms, and when the pressure is unloaded, the response time of the pressure sensor is 40ms. Therefore, it can be seen that the pressure sensor has a very fast response time and high sensitivity when loading and unloading pressure.

[0071] See also Figure 6 When pressures of 0.11KPa, 0.65KPa, 1.50KPa, 4.30KPa, 6.80KPa, 10.50KPa, 19.00KPa and 50.00KPa are applied to the flexible self-driven pressure sensor respectively, it can be seen that under each pressure condition, the pressure sensor has 5 cycles, which shows that the pressure sensor has good sensitivity and stability.

[0072] In some embodiments, see Figure 4The second and third dimensions of the MXene-based silica gel microstructure block 4 on the MXene-based silica gel layer 21 are both 700 μm, the first dimension of the MXene-based silica gel microstructure block 4 located at the center of the array is 1100 μm, the first dimension of the MXene-based silica gel microstructure block 4 located in the first structure ring 9 is 900 μm, the first dimension of the MXene-based silica gel microstructure block 4 located in the second structure ring 14 is 700 μm, and the first dimension of the silica gel microstructure block 4 located in the third structure ring 15 is 500 μm.

[0073] In some embodiments, the first size of the MXene-based silica gel microstructure block 4 in any one of the first structure ring 9, the second structure ring 14 and the third structure ring 15 is larger than that of other MXene-based silica gel microstructure blocks 4, and the first size of the MXene-based silica gel microstructure block 4 with the largest first size is equal to the height of the MXene-based isolation wall 5 on the MXene-based silica gel layer 21.

[0074] In some embodiments, the first dimensions of the MXene-based silica gel microstructure blocks 4 on the MXene-based silica gel layer 21 are all equal and are equal to the height of the MXene-based isolation wall 5 on the MXene-based silica gel layer 21 .

[0075] See also Figure 1 and Figure 7 In an embodiment of the present invention, a method for preparing a flexible self-driven pressure sensor is also proposed, comprising the following steps:

[0076] S1, preparing a microstructure resin template;

[0077] S2, preparing a MXene-based silica gel mixture;

[0078] S3, covering the microstructured resin template with a MXene-based silica gel mixture, curing the MXene-based silica gel mixture, and then peeling it off to obtain a MXene-based silica gel layer 21;

[0079] S4, combining the MXene-based silicone layer 21 and the pressure friction layer 22 to obtain the triboelectric pressure sensing portion 2;

[0080] S5. Assemble the triboelectric pressure sensing part 2, the bottom packaging part 1 and the top packaging part 3 to obtain a flexible self-driven pressure sensor.

[0081] In some embodiments, step S1 and step S2 may be performed in parallel.

[0082] In some embodiments, see Figure 1 and Figure 8 The process of executing step S1 includes:

[0083] S11, using computer software to draw a resin model having a microstructure; wherein the microstructure is a groove structure corresponding to the MXene-based silica gel microstructure block 4 and the MXene-based isolation wall 5;

[0084] S12. Print the resin model using a 3D printing device to obtain a resin template with a microstructure.

[0085] In some embodiments, when executing step S11, 3Dmax software is used to draw the resin model, which can improve the convenience of drawing the resin model and the degree of customization of the microstructure.

[0086] In some embodiments, when executing step S12, the 3D printing device uses a photosensitive resin material to perform 3D printing on the resin model, and uses a light-curing rapid prototyping method to shape and solidify the resin template.

[0087] In some embodiments, see Figure 9 The process of executing step S2 includes:

[0088] S21, preparing MXene powder;

[0089] S22. After uniformly mixing the MXene powder with the silica gel matrix, a MXene-based silica gel mixture is prepared; wherein the weight percentage of the MXene powder to the silica gel matrix is ​​2%-10%.

[0090] In some embodiments, the process of performing step S21 includes adding the Ti3AlC2-MAX precursor to a 1-3M hydrofluoric acid solution, reacting for 10-20 minutes, filtering, drying, and grinding to obtain MXene powder.

[0091] In some embodiments, the MXene powder is Ti3C2F2 powder.

[0092] In some embodiments, see Figure 10 The process of executing step S21 includes:

[0093] S211, preparing a low concentration hydrofluoric acid solution;

[0094] S212. Add the Ti3AlC2-MAX precursor to the HF solution and react for 10-20 minutes, then filter, dry and grind to obtain MXene powder.

[0095] In some embodiments, when step S211 is performed, the concentration of the low-concentration hydrofluoric acid solution is 1-3M.

[0096] In some embodiments, the process of performing step S211 includes weighing 1.65 g of lithium fluoride powder using an electronic balance, and slowly adding the lithium fluoride powder to 25 mL of 6 mol / L hydrochloric acid, and reacting for 10 minutes to form a low-concentration hydrofluoric acid solution.

[0097] In some embodiments, the process of executing step S212 includes weighing 1.25g of Ti3AlC2-MAX precursor using an electronic balance, slowly and gradually adding it to a low concentration hydrofluoric acid solution until it is completely added, placing the container containing the mixed solution in a constant temperature water bath at 35°C, and stirring the mixed solution at a speed of 350 rpm. After fully reacting for 48 hours, the Ti3C2F2 product is filtered out and the product is repeatedly washed and centrifuged with deionized water until the pH of the product reaches 6, vacuum filtering the product and placing it in a drying oven for drying, and grinding to obtain MXene powder.

[0098] In some embodiments, during step S212, when the Ti3C2F2 product is filtered out and the product is repeatedly washed and centrifuged using deionized water, the centrifugal speed is controlled to 8000 rpm, the centrifugal time is 10 minutes, and the number of washing centrifugation cycles is controlled to 10 times.

[0099] In some embodiments, during step S212 , when the product is vacuum filtered and placed in a drying oven for drying, the drying temperature is controlled to be 60° C., the drying environment is a vacuum environment, and the drying time is 6 hours.

[0100] In some embodiments, the process of executing step S22 includes: taking Ecoflex TM 00-01 glue A and glue B are uniformly mixed in a weight ratio of 1:1 to prepare a silica gel matrix. MXene powder is added to the silica gel matrix and uniformly mixed to prepare a MXene-based silica gel mixture. The weight ratio of MXene powder to silica gel matrix is ​​2%-10%.

[0101] In some embodiments, Ecoflex TM 00-01, Ecoflex TM The mass ratio of glue A and glue B in 00-01 is 1:(0.9-1.1).

[0102] In some embodiments, the ratio of the mass of the MXene-based silica gel mixture to the surface area of ​​the microstructured resin template is 0.1 g / cm 2 -0.3g / cm 2 .

[0103] In some embodiments, the process of performing step S3 includes: covering the MXene-based silica gel mixture on the microstructure resin template, placing it in a vacuum environment and standing for 25-35 minutes, drying and curing it, and then peeling it off to obtain the MXene-based silica gel layer 21.

[0104] In some embodiments, the process of executing step S3 includes: covering the MXene-based silica gel mixture on the side of the resin template having the microstructure, and placing the resin template and the MXene-based silica gel mixture in a vacuum drying oven and letting them stand and level in a vacuum environment for 30-35 minutes, taking them out and placing them in a 60°C oven for drying for 1 hour to solidify, and then peeling off to obtain the MXene-based silica gel layer 21.

[0105] In some embodiments, the process of executing step S4 includes: applying a silicone adhesive to the end of the MXene-based isolation wall 5 of the MXene-based silicone layer 21, thereby splicing the MXene-based silicone layer 21 and the pressure friction layer 22 to obtain the triboelectric pressure sensing portion 2.

[0106] In some embodiments, the process of executing step S5 includes coating a flexible silver nanowire electrode on the side of the MXene-based silicone layer 21 facing away from the MXene-based silicone microstructure block 4, and the length of the nanowire is 30-50 μm. After being led out with an aluminum electrode, the bottom of the MXene-based silicone layer 21 is encapsulated with pure silicone, and the encapsulation thickness is 30 μm; after the aluminum electrode is pasted on the pressure friction layer 22 and the electrode is led out, the aluminum electrode is covered by pasting it on the pressure friction layer 22, and the top of the MXene-based silicone layer 21 is encapsulated with pure silicone, and the encapsulation thickness is 30 μm.

[0107] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.

Claims

1. A flexible self-driven pressure sensor, characterized in that: It includes a bottom packaging part, a friction electric pressure sensing part and a top packaging part which are stacked in sequence from bottom to top; The triboelectric pressure sensing portion includes a stacked MXene-based silicone layer and a pressure friction layer; A plurality of MXene-based silica gel microstructure blocks and a plurality of MXene-based isolation walls are integrally formed on a side of the MXene-based silica gel layer close to the pressure friction layer, wherein one end of the plurality of MXene-based isolation walls relatively far from the MXene-based silica gel layer contacts the pressure friction layer, and the plurality of MXene-based silica gel microstructure blocks are located between the MXene-based silica gel layer and the pressure friction layer; The MXene-based silica gel microstructure block is arranged with a pointed end on a side close to the pressure friction layer; A plurality of MXene-based silica gel microstructure block arrays are arranged on the MXene-based silica gel layer; The first dimension of the plurality of MXene-based silica gel microstructure blocks decreases from the center of the array to the periphery of the array; the first dimension is the vertical distance between the end of the MXene-based silica gel microstructure block and the MXene-based silica gel layer; The MXene is a material with a two-dimensional structure formed by removing the main group elements from the MAX phase; The MAX phase is M n+1 AX n , wherein n is equal to any one of 1, 2 and 3, M is a transition metal element, A is a main group element, and X is a carbon element or a nitrogen element.

2. The flexible self-driven pressure sensor according to claim 1, characterized in that: The first dimensions of the plurality of MXene-based silica gel microstructure blocks are all equal; the first dimension is the vertical distance between the end of the MXene-based silica gel microstructure block and the MXene-based silica gel layer.

3. A method for preparing a flexible self-driven pressure sensor according to any one of claims 1 to 2, characterized in that: The following steps are involved: preparing a microstructured resin template; preparing a MXene-based silica gel mixture; Covering the MXene-based silica gel mixture on the microstructured resin template, and peeling off after curing to obtain a MXene-based silica gel layer; The MXene-based silicone layer and the pressure friction layer are assembled to obtain a triboelectric pressure sensing portion; The friction electric pressure sensing portion is assembled with the bottom packaging portion and the top packaging portion.

4. The method for preparing the flexible self-driven pressure sensor according to claim 3, characterized in that: The steps of preparing the MXene-based silica gel mixture include the following steps: Preparation of MXene powder; The MXene powder is evenly mixed with a silica gel matrix to prepare a MXene-based silica gel mixture; wherein the weight percentage of the MXene powder in the silica gel matrix is ​​2%-10%.

5. The method for preparing the flexible self-driven pressure sensor according to claim 4, characterized in that: The MXene powder is Ti3C2F2 powder.

6. The method for preparing the flexible self-driven pressure sensor according to claim 4, characterized in that: The steps of preparing MXene powder include adding a Ti3AlC2-MAX precursor to a 1-3M hydrofluoric acid solution, reacting for 10-20 minutes, filtering, drying, and grinding to obtain MXene powder.

7. The method for preparing the flexible self-driven pressure sensor according to claim 3, characterized in that: The step of covering the microstructured resin template with the MXene-based silica gel mixture and peeling off the MXene-based silica gel layer after curing comprises: The MXene-based silica gel mixture is covered on the microstructure resin template, placed in a vacuum environment and allowed to stand for 25-35 minutes, and then dried and cured to obtain a MXene-based silica gel layer.

8. The method for preparing the flexible self-driven pressure sensor according to claim 7, characterized in that: The ratio of the mass of the MXene-based silica gel mixture to the surface area of ​​the microstructured resin template is 0.1 g / cm 2 -0.3g / cm 2 .

Images