A flexible smart electronic skin and a preparation method and application thereof

Abstract

Disclosed are a flexible intelligent electronic skin, a preparation method and application thereof, the flexible intelligent electronic skin comprising a first organic silicone rubber functional layer, a first liquid metal conductive layer, a second organic silicone rubber functional layer, a second liquid metal conductive layer and a third organic silicone rubber functional layer; the first organic silicone rubber functional layer, the second organic silicone rubber functional layer and the third organic silicone rubber functional layer all comprise functional particles and organic silicone rubber having a boron-oxygen coordination bond, a hydrogen bond and a topological entanglement structure; the first liquid metal conductive layer and the second liquid metal conductive layer both comprise high-conductivity micrometer metal sheets and liquid metal. The flexible intelligent electronic skin of the application realizes multi-modal deep fusion, has self-healing, temperature sensing and wide-area tactile sensing capabilities, and can be applied to fields including human-computer interaction, health services, national defense and military industry and deep space and deep sea exploration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic skin design, manufacturing and application of humanoid robots, and mainly relates to a flexible intelligent electronic skin and a preparation method and application thereof. BACKGROUND

[0002] Humanoid robots are key equipment for humans to cope with global aging and achieve a better life in the future, and their role is increasingly prominent in key fields such as national defense and security, health services, and deep space exploration. As an important medium for humanoid robots to interact with the external environment, the performance of the electronic skin will greatly determine the practicality of the humanoid robot. Human skin contains a large number of sensory nerves that can perceive various external stimuli such as touch, pain, and temperature, and is an important functional organ for humans to perceive the external environment. In order to make the electronic skin have a comparable sensing ability to human skin, on the one hand, it is necessary to realize multi-modal fusion from the functional aspect to improve the effectiveness and sensitivity of the electronic skin in response to stimuli; on the other hand, it is necessary to realize deep bionics from the structural aspect to improve the flexibility of the electronic skin and achieve self-healing.

[0003] Currently published documents and patents mainly explore the functionality of electronic skin from a single field. Chinese patent CN117584578A discloses a self-healing light-emitting-power-generating elastic film and its preparation method and application. The self-healing light-emitting-power-generating elastic film includes, from top to bottom, a mechanoluminescence-power-generation layer, a conductive layer, and an encapsulation layer. The mechanoluminescence-power-generation layer is composed of mechanoluminescence powder and dielectric elastic polymer. The conductive layer is composed of solid-state conductive filler, conductive liquid, and dielectric elastic polymer. The encapsulation layer is composed of dielectric elastic polymer. The conductive liquid deforms with the dielectric elastic polymer during the stretching process of the dielectric elastic polymer, and realizes self-repair and dynamic compensation of the conductive path through active deformation and penetration. The self-healing light-emitting-power-generating elastic film can realize stress luminescence and friction power generation, and has high stretchability and self-healing ability, but does not explore the temperature sensing and wide-area touch sensing capabilities. Chinese patent CN117647336A discloses a capacitive wearable flexible pressure sensor based on gallium-based liquid metal and its preparation method. The sensor includes a porous elastomer dielectric layer made of gallium-based liquid metal, conductive carbon black, and polydimethylsiloxane. A gallium-based liquid metal fabric electrode is prepared by printing gallium-based liquid metal on a woven fabric. The invention can effectively improve the sensitivity and conductivity of the wearable flexible pressure sensor, and also enhances its mechanical adaptability, and has good softness and skin-friendliness, which can closely adhere to the human body or clothing, and is very suitable for wearable devices, electronic skin, and other application scenarios, but does not exhibit self-healing and temperature sensing capabilities.

[0004] In summary, current electronic skin has not achieved deep multimodal fusion in terms of functionality, and is severely lacking in the effectiveness and sensitivity of wide-area tactile and hot / cold stimulus responses. Furthermore, most electronic skins cannot achieve compatibility between wide-area elasticity and self-healing properties. Therefore, electronic skin still faces enormous challenges in achieving tactile sensing. Summary of the Invention

[0005] To address the problems existing in the prior art, this application proposes a flexible intelligent electronic skin, its preparation method, and its application. This solves the problems of existing electronic skins, such as the inability to self-heal, poor mechanical properties, single sensing mode and low sensitivity, and small detection range. It has great application potential in the field of electronic skin manufacturing and application for humanoid robots.

[0006] According to one aspect of this application, a flexible smart electronic skin is proposed, such as... Figure 1 As shown, the flexible smart electronic skin includes a first silicone rubber functional layer 1, a first liquid metal conductive layer 4, a second silicone rubber functional layer 2, a second liquid metal conductive layer 5, and a third silicone rubber functional layer 3. The first silicone rubber functional layer 1, the second silicone rubber functional layer 2, and the third silicone rubber functional layer 3 all contain functional particles and silicone rubber with boron-oxygen coordination bonds, hydrogen bonds, and topological entanglement structures. The first liquid metal conductive layer 4 and the second liquid metal conductive layer 5 both contain highly conductive micron-sized metal sheets and liquid metal. This flexible smart electronic skin structure achieves deep integration of multiple modes. Based on the inherent properties of silicone rubber and liquid metal, it possesses excellent self-healing capabilities. Simultaneously, based on the functional particles, highly conductive micron-sized metal sheets, and the special design of the overall structure, the flexible smart electronic skin also achieves excellent temperature sensing and wide-area tactile perception capabilities.

[0007] Furthermore, the mass ratio of the functional particles to the silicone rubber having boron-oxygen coordination bonds, hydrogen bonds, and topological entanglement structures is 1:5-100.

[0008] Furthermore, the functional particles include thermochromic powder and mechanoluminescent powder. Specifically, the functional particles added to the first silicone rubber functional layer 1 and the second silicone rubber functional layer 2 are both thermochromic powders, while the functional particles added to the third silicone rubber functional layer 3 are mechanoluminescent powders. The thermochromic powder enables the electronic skin to sense temperature, while the mechanoluminescent powder enables the electronic skin to sense stress to a certain extent.

[0009] Further, the organic silicone rubber having the boron-oxygen coordination bond, hydrogen bond and topological entanglement structure comprises the following components by mass percentage: boric acid 2.4wt%-7.6wt%, hydroxyl-terminated polydimethylsiloxane 45.5wt%-82.wt6%, vinyl-terminated polydimethylsiloxane 1.3wt%-5.6wt%, and trimethylsilane-terminated polydimethylhydrogen siloxane 14.8wt%-46.2wt%. The boron-oxygen coordination bond, hydrogen bond and topological entanglement structure endow the organic silicone rubber functional layer with self-healing ability, and the self-healing property is not sensitive to the environment (such as temperature and humidity).

[0010] Further, the mass ratio of the high-conductivity micrometer metal sheet to the liquid metal is 1:5-50.

[0011] Further, the high-conductivity micrometer metal sheet comprises one or more of micrometer nickel sheet, micrometer silver sheet and micrometer copper sheet. The micrometer nickel sheet can achieve better effect in improving wettability, the micrometer copper sheet has relatively good conductivity, and the micrometer silver sheet has the best conductivity.

[0012] Further, the liquid metal comprises the following components by mass percentage: metal indium 18wt%-22wt%, metal tin 8wt%-12wt%, and metal gallium 66wt%-74wt%. Since the liquid metal has good conductivity and flowability, the conductive layer formed of the liquid metal has excellent signal-to-noise ratio and fast self-healing ability, and is suitable for the self-healing conductive layer of the electronic skin.

[0013] According to a second aspect of the present application, a preparation method of a flexible intelligent electronic skin is provided, and the specific steps are as follows:

[0014] S1: preparing an organic silicone rubber functional layer having a boron-oxygen coordination bond, a hydrogen bond and a topological entanglement structure, including a first organic silicone rubber functional layer, a second organic silicone rubber functional layer and a third organic silicone rubber functional layer;

[0015] S2: preparing a liquid metal conductive layer, including a first liquid metal conductive layer and a second liquid metal conductive layer;

[0016] S3: sequentially stacking from top to bottom to form a flexible intelligent electronic skin of the first organic silicone rubber functional layer, the first liquid metal conductive layer, the second organic silicone rubber functional layer, the second liquid metal conductive layer and the third organic silicone rubber functional layer.

[0017] Further, in the S1, the specific preparation method of the organic silicon rubber functional layer with boron-oxygen coordination bond, hydrogen bond and topological entanglement structure is as follows: boric acid is added into a methanol solution to form a boric acid methanol solution; the boric acid methanol solution and the hydroxyl-terminated polydimethylsiloxane colloid are mixed and stirred to obtain colloid A; the vinyl-terminated polydimethylsiloxane and the trimethylsilane-terminated polydimethylhydrogen siloxane are mixed and stirred to obtain colloid B; the colloid A and the colloid B are mixed and stirred to obtain colloid C; the colloid C and functional particles are mixed and stirred to obtain colloid D; after the colloid D is dried, the first organic silicon rubber functional layer, the second organic silicon rubber functional layer and the third organic silicon rubber functional layer with boron-oxygen coordination bond, hydrogen bond and topological entanglement structure are prepared.

[0018] Further, in the S2, the specific preparation method of the liquid metal conductive layer is as follows: the selected metal is heated and mixed in vacuum to obtain a liquid metal mixture; the liquid metal mixture and high-conductive micrometer metal sheets are mixed and stirred to obtain a high-conductive liquid metal mixture; a metal mask plate containing a specific electronic circuit pattern is placed on the surface of the second organic silicon rubber functional layer and the third organic silicon rubber functional layer, and is subjected to ultraviolet ozone treatment, so as to improve the wettability of the liquid metal on the surface of the organic silicon rubber functional layer; the high-conductive liquid metal mixture is uniformly brushed on the surface of the second organic silicon rubber functional layer and the third organic silicon rubber functional layer covered with the metal mask plate, and after cold treatment, the metal mask plate is removed, to obtain a first liquid metal conductive layer and a second organic silicon rubber functional layer stacking structure, and a second liquid metal conductive layer and a third organic silicon rubber functional layer stacking structure, wherein the thicknesses of the first liquid metal conductive layer and the second liquid metal conductive layer are consistent with the metal mask plate.

[0019] Further, in the S3, the specific stacking method of the flexible intelligent electronic skin is as follows: one side of the first organic silicon rubber functional layer is subjected to ultraviolet ozone treatment, so as to be not easy to adhere dust, and the side is used as the outer surface of the flexible intelligent electronic skin; the second liquid metal conductive layer and the third organic silicon rubber functional layer stacking structure, the first liquid metal conductive layer and the second organic silicon rubber functional layer stacking structure, and the first organic silicon rubber functional layer are sequentially placed into an alignment mold from top to bottom, to form a five-layer structure of the first organic silicon rubber functional layer, the first liquid metal conductive layer, the second organic silicon rubber functional layer, the second liquid metal conductive layer and the third organic silicon rubber functional layer.

[0020] Further, the specific method for establishing the corresponding relationship between pressure and electrical signal and the corresponding relationship between chroma and temperature after the flexible smart electronic skin stack is completed is as follows: the metal wires such as flat cables and wire harnesses are connected with the electrode interfaces of the first liquid metal conductive layer, the charge signals of the triboelectric mode tactile sensing unit composed of the first organic silicone rubber functional layer and the first liquid metal conductive layer are processed and recognized by using the charge collection-processing system, so that the stress sensing in the range of 0.2-4kPa is obtained. The metal wires such as flat cables and wire harnesses are connected with the electrode interfaces of the first liquid metal conductive layer and the second liquid metal conductive layer, the capacitance signals of the capacitance mode tactile sensing unit composed of the first liquid metal conductive layer, the second organic silicone rubber functional layer and the second liquid metal conductive layer are processed and recognized by using the capacitance measurement-processing system, so that the stress sensing in the range of 4-28kPa is obtained. The quartz optical fiber is embedded in the third organic silicone rubber functional layer, the spectrum signals of the mechanoluminescence powder in the third organic silicone rubber functional layer under the action of large stress are processed and recognized by using the back-illuminated fiber spectrometer, so that the stress sensing in the range of 28-150kPa is obtained. The electronic skin is placed on the surface of a heating table, the temperature of the heating table is changed at 25-40℃, the chroma difference of the electronic skin caused by the change of temperature is calibrated, the corresponding relationship between the chroma of the electronic skin and the temperature is established, so that the electronic skin has the temperature sensing capability.

[0021] According to the third aspect of the present application, the flexible smart electronic skin is applied to the fields including human-computer interaction, health service, national defense and military industry and deep space and deep sea exploration.

[0022] Further, the application in the field of human-computer interaction includes a display touch screen.

[0023] Further, the application in the field of health service includes a wearable sports device.

[0024] Further, the application in the field of national defense and military industry includes an information encryption device.

[0025] Further, the application in the field of deep space exploration includes a spacecraft and a submersible sensing device.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The present application has three pressure detection modes of triboelectric mode, capacitance mode and mechanoluminescence mode and one temperature detection mode, has a wide pressure detection range (0.2-150kPa), high sensitivity (0.2-4kPa@0.98kPa -1 , 4-28kPa@0.11kPa -1 , 28-150kPa@1.12kPa -1), and full-structure self-healing. These excellent performances strongly guarantee the service reliability of the electronic skin in complex environments, and have great application potential in the field of electronic skin for humanoid robots. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 (a) and the stacking schematic diagram (b) of the flexible intelligent electronic skin of the present application.

[0029] Figure 2 (a) and the stacking schematic diagram (b) of the flexible intelligent electronic skin of the present application.

[0030] Figure 3 (a) and the stacking schematic diagram (b) of the flexible intelligent electronic skin of the present application.

[0031] Figure 4 (a) and the stacking schematic diagram (b) of the flexible intelligent electronic skin of the present application.

[0032] Figure 5 (a) and the stacking schematic diagram (b) of the flexible intelligent electronic skin of the present application.

[0033] In the figure, 1 is the first silicone rubber functional layer containing functional particles, 2 is the second silicone rubber functional layer containing functional particles, 3 is the third silicone rubber functional layer containing functional particles, 4 is the first liquid metal conductive layer containing high-conductive micrometer metal sheets, and 5 is the second liquid metal conductive layer containing high-conductive micrometer metal sheets. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below with reference to specific embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, and are not limited to the application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] Embodiment 1

[0036] A flexible intelligent electronic skin, and the specific preparation method is as follows:

[0037] S101, preparing a silicone rubber functional layer with boron-oxygen coordination bond, hydrogen bond and topological entanglement structure, including a first silicone rubber functional layer, a second silicone rubber functional layer and a third silicone rubber functional layer:

[0038] boric acid is fully ground, dried for 1-3h to remove crystal water; the boric acid powder is added to methanol, after sealing, heated to 30-50℃ and ultrasonic dispersed to obtain a 0.010-0.153g / mL boric acid methanol solution; the boric acid methanol solution is added dropwise to the hydroxyl-terminated polydimethylsiloxane colloid, mechanical stirring is maintained, the stirring speed is 100-300rpm, after the dropwise addition is completed, the stirring is continued for 0-30min, so that the boric acid and the hydroxyl-terminated polydimethylsiloxane are fully mixed, the mixture is defined as colloid A; the vinyl-terminated polydimethylsiloxane and the trimethylsilane-terminated polydimethylhydrogen siloxane are mixed and mechanically stirred, the stirring speed is 100-300rpm, the stirring time is 0.5-2h, so that the vinyl-terminated polydimethylsiloxane and the trimethylsilane-terminated polydimethylhydrogen siloxane are fully mixed, the mixture is defined as colloid B; the colloid A and the colloid B are mixed and mechanically stirred, the stirring speed is 100-300rpm, the stirring time is 0.5-2h, so that the colloid A and the colloid B are fully mixed, the mixture is defined as colloid C; the functional particles and the colloid solution C are mixed and mechanically stirred, the stirring speed is 100-300rpm, the stirring time is 0.5-2h, so that the functional particles and the colloid solution C are fully mixed, the mixture is defined as colloid D; the colloid D is poured into a 0.1-5mm thickness mold and placed in a vacuum oven, vacuum degassing is performed at room temperature for 1-10h, then heated to 160-200℃ for 2-6h, so that the components of the boric acid and the silicone rubber are fully reacted and crosslinked, thereby obtaining a silicone rubber functional layer with self-healing ability.

[0039] S102, preparing a liquid metal conductive layer:

[0040] The mixed metal is added to a ceramic crucible, vacuum heated to 100-120℃, and kept for 1-2h to obtain a liquid metal mixture; the high-conductivity micrometer metal sheet is mixed with the liquid metal mixture and mechanically stirred at a stirring speed of 100-300rpm for 0.5-2h to fully mix the high-conductivity micrometer metal sheet and the liquid metal mixture, and obtain a high-conductivity liquid metal mixture; the metal mask plate containing a specific electronic circuit pattern is placed on the surface of the second and third silicone rubber functional layers, the mask plate has a thickness of 0.05-0.3mm, and the 185 / 254nm dual-wavelength ultraviolet ozone generator is used for treatment for 0.5-2h to improve the wettability of the liquid metal on the silicone rubber without mask shielding; the high-conductivity liquid metal mixture is uniformly brushed on the surface of the second and third silicone rubber functional layers covered with the metal mask plate, so that the thickness of the liquid metal conductive layer is consistent with that of the mask plate; the second and third silicone rubber functional layers brushed with the high-conductivity liquid metal mixture are subjected to freezing treatment, the freezing temperature is-10-0℃, and the freezing time is 0.1-0.5h, the frozen metal mask plate is removed from the surface of the silicone rubber functional layer, and a first liquid metal conductive layer and a second silicone rubber functional layer stacked structure, and a second liquid metal conductive layer and a third silicone rubber functional layer stacked structure are obtained.

[0041] S103, stacking the flexible intelligent electronic skin:

[0042] The 185 / 254nm dual-wavelength ultraviolet ozone generator is used for surface treatment of one side of the first silicone rubber functional layer, the treatment time is 0.5-2h, and the side is defined as the outer surface of the electronic skin, and the process makes it not easy to adhere dust; the second liquid metal conductive layer and the third silicone rubber functional layer stacked structure, the first liquid metal conductive layer and the second silicone rubber functional layer stacked structure, and the first silicone rubber functional layer are sequentially placed in an alignment mold from top to bottom to form a five-layer structure of the first silicone rubber functional layer, the first liquid metal conductive layer, the second silicone rubber functional layer, the second liquid metal conductive layer, and the third silicone rubber functional layer, and kept at room temperature to 100℃ for 0.5-1h.

[0043] S104, establishing the correspondence between pressure and electrical signal, and the correspondence between chroma and temperature:

[0044] The metal wires such as flat cable, wire harness wire, etc. are connected with the electrode interface of the first liquid metal conductive layer, the charge signals of the triboelectric mode tactile sensing unit composed of the first organic silicone rubber functional layer and the first liquid metal conductive layer are processed and recognized by using the charge collection-processing system, so that the stress sensing in the range of 0.2-4kPa is obtained. The metal wires such as flat cable, wire harness wire, etc. are connected with the electrode interface of the first liquid metal conductive layer and the second liquid metal conductive layer, the capacitance signals of the capacitance mode tactile sensing unit composed of the first liquid metal conductive layer, the second organic silicone rubber functional layer and the second liquid metal conductive layer are processed and recognized by using the capacitance measurement-processing system, so that the stress sensing in the range of 4-28kPa is obtained. The quartz optical fiber is embedded in the third organic silicone rubber functional layer, the spectral signals of the mechanoluminescence powder in the third organic silicone rubber functional layer under the action of large stress are processed and recognized by using the back-illuminated fiber spectrometer, so that the stress sensing in the range of 28-150kPa is obtained. The electronic skin is placed on the surface of the heating table, the temperature of the heating table is changed at 25-40℃, the chromatic difference caused by the change of the electronic skin with temperature is calibrated, the corresponding relationship between the chromaticity of the electronic skin and the temperature is established, so that the electronic skin has the temperature sensing capability.

[0045] Example 2

[0046] An organic silicone rubber functional layer containing a thermochromic powder, the specific preparation method is as follows:

[0047] S201, the boric acid is ground and dried for 2h to remove the crystal water;

[0048] S202, 0.3g of boric acid powder is weighed and added into 30ml of methanol, after sealing treatment, heated to 40℃ and ultrasonic dispersed, to obtain a boric acid methanol solution with a concentration of 0.01g / mL;

[0049] S203, the above boric acid methanol solution is added dropwise into 4.5g of hydroxyl-terminated polydimethylsiloxane colloid, mechanical stirring is kept, the stirring speed is 150rpm, after the dropwise addition is completed, the stirring is continued for 20min, so that the boric acid and the hydroxyl-terminated polydimethylsiloxane are fully mixed, the mixture is defined as colloid A;

[0050] S204, 0.12g of vinyl-terminated polydimethylsiloxane and 1.08g of trimethylsilane-terminated polydimethylhydrogen siloxane are weighed respectively and mixed, mechanical stirring is kept, the stirring speed is 200rpm, the stirring time is 1h, so that the vinyl-terminated polydimethylsiloxane and the trimethylsilane-terminated polydimethylhydrogen siloxane are fully mixed, the mixture is defined as colloid B;

[0051] S205, mechanically stir the mixture of colloidal A and colloidal B after mixing, the stirring speed is 150 rpm, and the stirring time is 1 h, so that colloidal A and colloidal B are fully mixed, and the mixture is defined as colloidal C;

[0052] S206, 0.06 g of temperature-sensitive color-changing powder is weighed and added to colloidal C, and then mechanically stirred after mixing, the stirring speed is 150 rpm, and the stirring time is 0.5 h, so that the temperature-sensitive color-changing powder and colloidal C are fully mixed, and the mixture is defined as colloidal D;

[0053] S207, pour colloidal D into a mold with a thickness of 0.1 mm and place it in a vacuum oven, vacuum degassing at room temperature for 6 h, and then heating to 170 DEG C for 6 h, so that the components are fully reacted and crosslinked, thereby obtaining a silicone rubber functional layer containing temperature-sensitive color-changing powder;

[0054] S208, place the silicone rubber functional layer on the surface of a heating table at 25 DEG C and 40 DEG C respectively, and the results are shown in Figure 2 , the silicone rubber functional layer shows blue at 25 DEG C, and the silicone rubber functional layer shows green at 40 DEG C.

[0055] Example 3

[0056] A kind of organic silicon rubber functional layer containing luminescent powder, its specific preparation method is as follows:

[0057] S301, the boric acid is fully ground, and dried for 2 h to remove crystallization water;

[0058] S302, 0.5 g of boric acid powder is weighed and added to 40 ml of methanol, sealed and heated to 50 DEG C and ultrasonically dispersed to obtain a boric acid methanol solution with a concentration of 0.0125 g / mL;

[0059] S303, the above boric acid methanol solution is added dropwise to 10 g of hydroxyl-terminated polydimethylsiloxane colloidal, mechanical stirring is maintained, the stirring speed is 150 rpm, and after the dropwise addition is completed, the stirring is continued for 20 min, so that the boric acid and the hydroxyl-terminated polydimethylsiloxane are fully mixed, and the mixture is defined as colloidal A;

[0060] S304, 0.24 g of vinyl-terminated polydimethylsiloxane and 2.385 g of trimethylsilane-terminated polydimethylhydrogen siloxane are weighed and mixed, and then mechanically stirred, the stirring speed is 200 rpm, and the stirring time is 1 h, so that the vinyl-terminated polydimethylsiloxane and the trimethylsilane-terminated polydimethylhydrogen siloxane are fully mixed, and the mixture is defined as colloidal B;

[0061] S305, mechanically stir the mixture of colloidal A and colloidal B after mixing, the stirring speed is 150 rpm, and the stirring time is 1 h, so that colloidal A and colloidal B are fully mixed, and the mixture is defined as colloidal C;

[0062] S306, 0.15 g of piezoluminescent powder is weighed and added to colloidal C, and then mechanically stirred after mixing, the stirring speed is 150 rpm, and the stirring time is 0.5 h, so that the piezoluminescent powder and colloidal C are fully mixed, and the mixture is defined as colloidal D;

[0063] S307, pour colloidal D into a mold with a thickness of 0.2 mm and place it in a vacuum oven, vacuum degassing at room temperature for 6 h, and then heat to 200℃ for 4 h, so that the components are fully reacted and crosslinked, thereby obtaining a silicone rubber functional layer containing piezoluminescent powder.

[0064] Example 4

[0065] A flexible intelligent electronic skin with self-healing, temperature sensing, and wide-area tactile sensing capability, and its specific preparation method is as follows (as shown in Figure 3 ):

[0066] S401, the first and second silicone rubber functional layers containing thermochromic powder are prepared according to Example 2, and the third silicone rubber functional layer containing piezoluminescent powder is prepared according to Example 3;

[0067] S402, cut the above-mentioned silicone rubber functional layer to the required size for standby;

[0068] S403, weigh 2.1 g of metallic indium, 1 g of metallic tin, and 6.9 g of metallic gallium, and add the three metals to a crucible, vacuum heat to 120℃, and keep the temperature for 1-2 h to obtain a liquid metal mixture;

[0069] S404, 1 g of micron nickel sheet is weighed and added to the liquid metal mixture and stirred, the stirring speed is 200 rpm, and the stirring time is 1 h, so that the micron nickel sheet and the liquid metal mixture are fully mixed, and a high-conductivity liquid metal mixture is obtained;

[0070] S405, place a metal mask plate containing a specific electronic circuit pattern on the surface of the second and third silicone rubber functional layers, the mask plate has a thickness of 0.1 mm, and use a 185 / 254 nm dual-wavelength ultraviolet ozone generator to treat for 1 h, thereby improving the wettability of the silicone rubber in the unmasked shielding part to the liquid metal;

[0071] S406, uniformly brush the high-conductivity liquid metal mixture on the surface of the second and third silicone rubber functional layers covered with the metal mask plate, so that the liquid metal conductive layer is consistent with the thickness of the mask plate;

[0072] S407. The second and third silicone rubber functional layers coated with a highly conductive liquid metal mixture are frozen at -5°C for 0.2 hours. After freezing, the metal mask is removed from the surface of the silicone rubber functional layers to obtain a stacked structure of the first liquid metal conductive layer and the second silicone rubber functional layer, as well as a stacked structure of the second liquid metal conductive layer and the third silicone rubber functional layer.

[0073] S408. The first silicone rubber functional layer is surface treated on one side using a 185 / 254nm dual-wavelength ultraviolet ozone generator for 1 hour to prevent dust from easily adhering when used as an electronic skin surface.

[0074] S409. The first liquid metal conductive layer and the second silicone rubber functional layer are stacked in sequence, followed by the first liquid metal conductive layer and the second silicone rubber functional layer, and then the first silicone rubber functional layer. The first layer is placed into the alignment mold in sequence, forming a five-layer structure from top to bottom: the first silicone rubber functional layer, the first liquid metal conductive layer, the second silicone rubber functional layer, the second liquid metal conductive layer, and the third silicone rubber functional layer. The mixture is heated to 60°C and kept at that temperature for 0.5 hours to form a stable electronic skin tactile sensing unit.

[0075] S410. Connect the wire harness to the electrode interface of the first liquid metal conductive layer. Use a charge acquisition and processing system to process and identify the charge signal of the triboelectric mode tactile sensing unit composed of the first silicone rubber functional layer and the first liquid metal conductive layer, thereby obtaining stress sensing within the range of 0.2-4 kPa. Figure 4 As shown in Figure a, metal wires such as ribbon cables and wire harnesses are connected to the electrode interfaces of the first liquid metal conductive layer and the second liquid metal conductive layer. A capacitance measurement-processing system is used to process and identify the capacitance signal of the capacitance-mode tactile sensing unit composed of the first liquid metal conductive layer, the second silicone rubber functional layer, and the second liquid metal conductive layer, thereby obtaining stress sensing within the range of 4-28 kPa. Figure 4 As shown in b; a quartz optical fiber is embedded in the third silicone rubber functional layer, and a back-illuminated fiber optic spectrometer is used to process and identify the stress luminescence signal, thereby obtaining stress sensing within the range of 28-150 kPa, such as... Figure 4 As shown in c.

[0076] Example 5

[0077] A flexible smart electronic skin with self-healing and temperature-sensing capabilities is prepared as follows:

[0078] S501, the silicone rubber functional layer containing thermochromic powder 1 (red) and thermochromic powder 2 (blue) is prepared according to embodiment 2;

[0079] S502, the silicone rubber functional layer is cut to the required size for standby;

[0080] S503, the high-conductive liquid metal mixture containing micron nickel pieces is prepared according to embodiment 4;

[0081] S504, the metal mask plate containing straight line patterns is placed on the surface of the silicone rubber functional layer, the mask plate thickness is 0.1 mm, and the 185 / 254 nm dual-wavelength ultraviolet ozone generator is used for treatment for 1 h, so as to improve the wettability of the silicone rubber without mask shielding part to the liquid metal;

[0082] S505, the high-conductive liquid metal mixture is uniformly brushed on the surface of the silicone rubber functional layer covered with the metal mask plate, so that the liquid metal conductive layer is consistent with the thickness of the mask plate;

[0083] S506, the silicone rubber functional layer brushed with the high-conductive liquid metal mixture is frozen, the freezing temperature is-3℃, and the freezing time is 0.2 h, the frozen metal mask plate is taken off from the surface of the silicone rubber functional layer, and a liquid metal conductive layer and a silicone rubber functional layer stacked structure is obtained;

[0084] S507, the wire is connected with the electrode interface of the liquid metal conductive layer, and the power supply is connected with the LED lamp bead, so as to form a simple power circuit, as shown in Figure 5 a; the simple circuits of "liquid metal conductive layer / silicone rubber functional layer (red)" and "liquid metal conductive layer / silicone rubber functional layer (blue)" are cut off respectively, the two kinds of half-cut samples are reconnected, the circuit reconstruction is realized by using the full structure self-healing, and the LED lamp bead is re-lit.

[0085] The self-healing efficiency of the above sample at room temperature is evaluated, as shown in Figure 5 b, the self-healing efficiency is recovered to 22.8% of the initial value after 4 h, and the self-healing efficiency is recovered to 84.2% of the initial value after 24 h, and the results show that the flexible intelligent electronic skin has excellent self-healing ability.

[0086] The specific embodiments of the present application are described above, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0087] In the description of the application, it needs to be understood that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. The word 'comprising' does not exclude the existence of elements or steps not listed in the claims. The word 'a' or 'an' in front of an element does not exclude the existence of multiple such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that the combination of these measures cannot be used to improve. Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. A flexible intelligent electronic skin, characterized in that: The flexible intelligent electronic skin includes a first silicone rubber functional layer, a first liquid metal conductive layer, a second silicone rubber functional layer, a second liquid metal conductive layer, and a third silicone rubber functional layer. The first, second, and third silicone rubber functional layers each contain functional particles and silicone rubber with boron-oxygen coordination bonds, hydrogen bonds, and topological entanglement structures. The functional particles include thermochromic powder and metronome powder; The organosilicon rubber having boron-oxygen coordination bonds, hydrogen bonds, and topological entanglement structures comprises, by weight percentage, the following components: boric acid 2.4wt%-7.6wt%, hydroxyl-terminated polydimethylsiloxane 45.5wt%-82.6wt%, vinyl-terminated polydimethylsiloxane 1.3wt%-5.6wt%, and trimethylsilane-terminated polydimethylhydrosiloxane 14.8wt%-46.2wt%. Both the first liquid metal conductive layer and the second liquid metal conductive layer comprise highly conductive micron-sized metal sheets and liquid metal; The liquid metal comprises the following components by mass percentage: 18wt%-22wt% indium, 8wt%-12wt% tin, and 66wt%-74wt% gallium.

2. The flexible intelligent electronic skin according to claim 1, characterized in that: The mass ratio of the functional particles to the silicone rubber having boron-oxygen coordination bonds, hydrogen bonds, and topological entanglement structures is 1:5-100.

3. The flexible intelligent electronic skin according to claim 1, characterized in that: The functional particles added to the first and second silicone rubber functional layers are both thermochromic powders, and the functional particles added to the third silicone rubber functional layer are mechanoluminescent powders.

4. The flexible intelligent electronic skin according to claim 1, characterized in that: The mass ratio of the highly conductive micron-sized metal sheet to the liquid metal is 1:5-50.

5. The flexible intelligent electronic skin according to claim 1, characterized in that: The highly conductive micron-sized metal sheet includes one or more of micron-sized nickel sheets, micron-sized silver sheets, and micron-sized copper sheets.

6. A method for preparing flexible intelligent electronic skin as described in any one of claims 1-5, characterized in that, The specific steps are as follows: S1: Prepare an organosilicon rubber functional layer with boron-oxygen coordination bonds, hydrogen bonds and topological entanglement structure, including a first organosilicon rubber functional layer, a second organosilicon rubber functional layer and a third organosilicon rubber functional layer; S2: Prepare a liquid metal conductive layer, including a first liquid metal conductive layer and a second liquid metal conductive layer; S3: A flexible smart electronic skin formed by stacking in an orderly manner from top to bottom, consisting of a first silicone rubber functional layer, a first liquid metal conductive layer, a second silicone rubber functional layer, a second liquid metal conductive layer, and a third silicone rubber functional layer.

7. The method for preparing flexible intelligent electronic skin according to claim 6, characterized in that: In S1, the specific preparation method of the organosilicon rubber functional layer with boron-oxygen coordination bonds, hydrogen bonds, and topological entanglement structure is as follows: boric acid is added to a methanol solution to form a boric acid methanol solution; the boric acid methanol solution and hydroxyl-terminated polydimethylsiloxane colloid are mixed and stirred to obtain colloid A; vinyl-terminated polydimethylsiloxane and trimethylsilane-terminated polydimethylhydrosiloxane are mixed and stirred to obtain colloid B; colloid A and colloid B are mixed and stirred to obtain colloid C; colloid C and functional particles are mixed and stirred to obtain colloid D; after drying colloid D, the organosilicon rubber functional layer with boron-oxygen coordination bonds, hydrogen bonds, and topological entanglement structure is prepared.

8. The method for preparing flexible intelligent electronic skin according to claim 6, characterized in that: After the flexible smart electronic skin is stacked, a correspondence between pressure and electrical signal is established to obtain the stress sensing range of the flexible smart electronic skin, a correspondence between color and temperature is established, and the color difference of the electronic skin caused by temperature changes is calibrated.

9. An application of flexible intelligent electronic skin as described in any one of claims 1-5, characterized in that: The flexible intelligent electronic skin has applications in fields including human-computer interaction, health services, national defense and military industry, and deep space and deep sea exploration.

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