Bionic cilia electronic skin and preparation method thereof

Abstract

The present application belongs to the technical field of electronic skin, and particularly relates to a bionic cilium electronic skin and a preparation method thereof. The bionic cilium electronic skin provided by the present application comprises a flexible substrate, a flexible circuit layer arranged on the surface of the flexible substrate, and a flexible cilium layer arranged on the surface of the flexible circuit layer. The flexible circuit layer is provided with a two-dimensional circuit array, and the flexible cilium layer is provided with a cilium sensing array. The cilium sensing array is formed by arranging a cilium sensing unit array, and the cilium sensing unit is a three-dimensional cilium structure. The bionic cilium electronic skin further comprises liquid metal filled in the two-dimensional circuit microchannels. The present application combines the two-dimensional sensing unit with the cilium sensing unit, simulates the differentiation function of skin, realizes the functional differentiation of the electronic skin, and successfully realizes the real-time monitoring of multiple different detection sensing functions such as surface touch, surface sliding and surface airflow speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic skin, and in particular relates to a bionic ciliary electronic skin and a preparation method thereof. Background Art

[0002] Electronic devices that are inspired by human skin and mimic the properties of skin are called "electronic skins" (e-skins). They have recently emerged with the innovation of materials and processing technologies. Electronic skins are widely used in health monitoring, robotic tactile perception, bionic prostheses and other fields because of their ability to detect a wide variety of signals. Electronic skin functional devices are mainly based on pressure sensor arrays on flexible substrates, and currently cover a wide range of physical and chemical sensing modes, including but not limited to temperature, strain, electrophysiology, ions, biomarkers, metabolites, gases, etc. In addition to soft and bendable base materials, electronic skins also require conductive functional materials to achieve circuit connection and functional perception. The flexibility of conductive functional materials is of great significance for electronic skins to maintain sensing performance under tension and compression.

[0003] Electronic skin is a stretchable, flexible sensor attached to the human body that can sense external stimuli. It has attracted widespread attention due to its lightweight, low modulus, low cost, high flexibility, and excellent stretchability. Currently, flexible and stretchable biomimetic sensing electronics are gaining widespread attention in areas such as human-machine interfaces, robotic smart skin, medical monitoring, and bio-integrated devices. Compared to traditional rigid and brittle silicon-based electronics, flexible and stretchable sensing electronics, due to their elastic properties, can effectively capture high-quality signals on curved surfaces and are expected to play a vital role in the foreseeable intelligent era.

[0004] However, most current flexible electronic skins do not have both high sensitivity and a wide detection range. Their detection range is usually very narrow, and their sensitivity drops rapidly when they are under considerable or even moderate pressure, which limits their application in flexible sensors, integrated electronic skin, and human health monitoring devices. Summary of the Invention

[0005] The purpose of the present invention is to provide a bionic ciliary electronic skin and a preparation method thereof. The bionic ciliary electronic skin provided by the present invention has the characteristics of wide sensing range, short response time and high sensing sensitivity. It has sensing performance in flat and curved environments and can successfully realize the application of surface morphology recognition, Braille reading, and bionic skin differentiation functions.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The application provides a bionic cilia electronic skin, which comprises a flexible substrate, a flexible circuit layer arranged on the surface of the flexible substrate, and a flexible cilia layer arranged on the surface of the flexible circuit layer.

[0008] The flexible circuit layer is provided with a two-dimensional circuit array formed by an array of two-dimensional circuit units, and the two-dimensional circuit unit is formed by a two-dimensional circuit microchannel.

[0009] The flexible cilia layer is provided with a cilia sensing array formed by an array of cilia sensing units, and the cilia sensing unit is a three-dimensional cilia-shaped structure.

[0010] The area of the orthographic projection of the cilia sensing unit on the surface of the flexible substrate at least partially overlaps with the area of the orthographic projection of the two-dimensional circuit unit on the surface of the flexible substrate.

[0011] The bionic cilia electronic skin further comprises a liquid metal filled in the two-dimensional circuit microchannel.

[0012] Preferably, the shape of the two-dimensional circuit unit is a square spiral line pattern formed by the two-dimensional circuit microchannel; the side length of the two-dimensional circuit unit is 3 mm, the circuit density is 32.0 cm -1 , the spacing between adjacent two two-dimensional circuit units is 1-2 mm, and the cross-sectional shape of the two-dimensional circuit microchannel is a square of 0.1*0.1 mm 2 .

[0013] Preferably, the shape of the three-dimensional cilia-shaped structure is a solid cone, the base diameter of the three-dimensional cilia-shaped structure is 0.8-2 mm, and the height is 2.5-4.5 mm.

[0014] Preferably, the thickness of the flexible substrate, the flexible circuit layer and the flexible cilia layer is all 0.5 mm.

[0015] The material of the flexible substrate is polydimethylsiloxane; the materials of the flexible circuit layer and the flexible cilia layer are platinum-catalyzed silicone rubber; the liquid metal is oxidized EGaIn, the surface tension of the oxidized EGaIn is 517 mN·m -1 , and the viscosity is 2.3*10 4 mPa·s.

[0016] Preferably, the preparation method of the oxidized EGaIn comprises the following steps:

[0017] Mixing the EGaIn, the inorganic strong base and water to oxidize and obtain the oxidized EGaIn; the oxidation time is 2-6 h.

[0018] The present invention provides a method for preparing the bionic ciliary electronic skin described in the above technical solution, comprising the following steps:

[0019] The cilia template, circuit template and blank base plate are obtained by 3D printing;

[0020] Using the template method, a flexible ciliary layer, a flexible circuit layer, and an uncured flexible substrate were prepared using a ciliary template, a circuit template, and a blank substrate, respectively.

[0021] The flexible cilia layer, the flexible circuit layer and the flexible substrate in an uncured state are sequentially stacked and bonded to obtain a semi-finished product;

[0022] Liquid metal is injected into the two-dimensional circuit microchannel of the semi-finished product to obtain the bionic ciliary electronic skin.

[0023] Preferably, the raw material used in the 3D printing is a photosensitive resin; the 3D printing directly obtains an initial state cilia template or an initial state circuit template;

[0024] After obtaining the initial state cilia template, the method further includes: washing, photocuring and hydrophobicizing the initial state cilia template in sequence to obtain the cilia template;

[0025] After the initial circuit template is obtained, the method further includes: washing and light-curing the initial circuit template in sequence to obtain the circuit template.

[0026] Preferably, the preparation of the flexible cilia layer or the flexible circuit layer by the template method comprises the following steps:

[0027] Mixing component A and component B of platinum-catalyzed silicone rubber and coating the mixture on the ciliary template or circuit template, and then performing demoulding after heat curing to obtain a flexible ciliary layer or a flexible circuit layer;

[0028] The coating thickness is 0.5 mm; the thermal curing temperature is 45° C. and the curing time is 20 min.

[0029] Preferably, the preparation of the flexible substrate in an uncured state by the template method comprises the following steps:

[0030] The basic components of polydimethylsiloxane and a curing agent are mixed and then coated on a blank base plate, and demoulded after thermal curing to obtain a flexible substrate in an uncured state;

[0031] The coating thickness is 0.5 mm, and the thermal curing temperature is 45° C. for 2.5 hours.

[0032] The present invention provides the application of the bionic ciliary electronic skin described in the above technical solution or the bionic ciliary electronic skin prepared by the preparation method described in the above technical solution in constructing bionic robots, preparing intelligent prostheses or preparing multi-dimensional detection equipment.

[0033] The present invention provides a biomimetic ciliary electronic skin comprising a flexible substrate, a flexible circuit layer disposed on the surface of the flexible substrate, and a flexible ciliary layer disposed on the surface of the flexible circuit layer; the flexible circuit layer being provided with a two-dimensional circuit array, the two-dimensional circuit array being formed by an array of two-dimensional circuit units, the two-dimensional circuit units being formed by two-dimensional circuit microchannels; the flexible ciliary layer being provided with a ciliary sensor array, the ciliary sensor array being formed by an array of ciliary sensor units, the ciliary sensor units being three-dimensional ciliary structures; the orthographic projection areas of the ciliary sensor units on the surface of the flexible substrate at least partially overlapping with the orthographic projection areas of the two-dimensional circuit units on the surface of the flexible substrate; and the biomimetic ciliary electronic skin further comprising liquid metal filled within the two-dimensional circuit microchannels. The present invention combines a three-dimensional structure with a two-dimensional sensor element, significantly increasing the sensing range of the flexible sensor. This enables the biomimetic ciliary electronic skin prepared by the present invention to move from basic contact touch and physiological signal sensing to sensing bending and folding, and even to sensing surface object topography, gas, and fluid sensing. From the results of the examples, it can be seen that the bionic ciliary electronic skin prepared by the present invention has a single ciliary sensing unit with a frequency detection range of 1-25Hz and a response time of 0.4s, and can perform linear sensing in a bending range of 15° to 60°. In terms of functional applications, the single ciliary sensing unit can effectively identify various surface topography with an accuracy of up to 0.2mm, and the integrated ciliary sensing array can achieve rapid reading of Braille. The present invention combines a two-dimensional sensing unit with a ciliary sensing unit, simulates the skin differentiation function, realizes the functional differentiation of the electronic skin, and successfully realizes the real-time monitoring of multiple different detection sensing functions such as surface touch, surface sliding and surface airflow velocity.

[0034] The present invention provides a method for preparing the biomimetic ciliary electronic skin described in the above technical solution, comprising the following steps: using a 3D printing method to obtain a ciliary template, a circuit template, and a blank base; using a template method to prepare a flexible ciliary layer, a flexible circuit layer, and a flexible substrate in an uncured state from the ciliary template, the circuit template, and the blank base, respectively; stacking the flexible ciliary layer, the flexible circuit layer, and the uncured flexible substrate in sequence and bonding them to obtain a semi-finished product; and injecting liquid metal into the two-dimensional circuit microchannels of the semi-finished product to obtain the biomimetic ciliary electronic skin. The preparation method provided by the present invention uses an additive manufacturing (3D printing) method and a template method to produce a flexible biomimetic ciliary electronic skin electronic device. After modular assembly, the present invention can obtain a high-performance flexible biomimetic ciliary electronic skin. At the same time, by reserving ciliary holes on the template for demolding, the present invention can simultaneously prepare a customizable ciliary structure on the surface of the electronic skin, breaking through the limitations of traditional flexible electronic skin's single-dimensional detection and realizing real-time detection, sensing, and monitoring of touch, sliding, and airflow.

[0035] In summary, the flexible circuit layer in the bionic ciliary electronic skin provided by the present invention has a sensing range spanning three orders of magnitude (10-22000Pa) and a fast response time (0.14s); the ciliary electronic skin sensing unit (bottom diameter D = 2mm, ciliary length H = 3.5mm) has a 15°-60° bending linear sensing range, a fast response time of 0.4s and a 1-25Hz wide frequency range capability. The critical spacing of 2mm enables the ciliary electronic skin to have the two-point resolution capability of the human fingertips. The same linear sensing range (15°-60°) as that of the plane environment in a complex curved surface environment (curvature radius ≥ 6mm) means that the electronic skin can adapt to the curved surface environment of the human body surface. Based on the successful preparation of ciliary electronic skin, the present invention has made specific functional applications to it. Single ciliary electronic skin can accurately identify and measure different surface morphologies, and can achieve a resolution of 0.2mm for the structures of tetrahedrons, cubes and hemispheres. Multi-ciliary electronic skin can rapidly read Braille, and integrated signal analysis from three sensor units allows for rapid identification of Braille. This invention also incorporates an embedded rigid structure to enhance airflow perception. Through experimental studies of multi-touch and sliding touch combined with airflow effects, the ciliary electronic skin can simultaneously detect pressure, trajectory, and airflow on curved surfaces, demonstrating superior capabilities in the differentiation of biomimetic electronic skin functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart for preparing the bionic ciliary electronic skin provided in the present invention;

[0037] Figure 2The open circuit phenomenon of the millimeter-scale sensing unit when filled with pure EGaIn (unoxidized);

[0038] Figure 3 is the change of surface tension, viscosity and contact angle after oxidation of EGaIn, where Figure 3 (a) shows the change of EGaIn surface tension with oxidation time; Figure 3 (b) shows the change of EGaIn viscosity with oxidation time; Figure 3 (c) shows the change of contact angle of EGaIn on Ecoflex material with oxidation time; Figure 3 (d) shows the change of contact angle of EGaIn on PDMS material with oxidation time;

[0039] Figure 4 is the change of EGaIn oxidation mass fraction and conductivity with oxidation time, Figure 4 (a) shows the change of EGaIn oxidation mass fraction with oxidation time; Figure 4 (b) shows the change of EGaIn conductivity with oxidation time;

[0040] Figure 5 This is an optical microscope image of the two-dimensional sensing unit prepared in Example 2;

[0041] Figure 6 This is a pressure resolution characterization diagram of the two-dimensional sensing unit prepared in Example 2 in response to pressure load. Figure 6 (a) shows the response results of the sensor unit in the step-by-step loading experiment; Figure 6 (b) is the linear response fitting of the array sensor unit to different weight loading weights; Figure 6 (c) is the bar graph of the response time of the array sensor unit to different weight loading. Figure 6 (d) and (e) Figure 6 The two illustrations in (a);

[0042] Figure 7 For the characterization of the ciliary structure in the present invention, Figure 7 (a) is the characterization of ciliary structural parameters; Figure 7 (b) is a light microscopic image of cilia (D = 2 mm, H = 3.5 mm); Figure 7 (c) is a light microscopic image of cilia with a cilia length H of 2.5 mm and different bottom diameters D; Figure 7 (d) is a schematic diagram of cilia bending;

[0043] Figure 8 The response results and changes of the ciliary sensor under different ciliary bending degrees are shown. Figure 8 (a) shows the response results of cilia with different bottom diameters and a length of 2.5 mm; Figure 8 (b) shows the response results of cilia with different bottom diameters and a length of 3.5 mm; Figure 8 (c) shows the response results of cilia with a length of 4.5 mm and different bottom diameters;

[0044] Figure 9 is the response time and change of the ciliary sensor under different ciliary bending degrees, Figure 9 (a) shows the response time of cilia with different bottom diameters and a length of 2.5 mm; Figure 9 (b) shows the response time of cilia with different bottom diameters and a length of 3.5 mm; Figure 9 (c) shows the response time of cilia with a length of 4.5 mm and different bottom diameters;

[0045] Figure 10 is the three-factor diagram of ciliary resistance response;

[0046] Figure 11 is the three-factor diagram of ciliary response time;

[0047] Figure 12 To characterize the performance of single cilia, Figure 12 (a) shows the response results when the cilia are bent at 15°, 30°, 45°, and 60°; Figure 12 (b) is the sinusoidal fitting result of the response size and bending angle; Figure 12 (c) shows the relationship between the ciliary bending angle and the response time;

[0048] Figure 13 is the ciliary frequency sensing range;

[0049] Figure 14 To characterize the ciliary propulsion performance, Figure 14 (a) is the resistance response curve under different push positions; Figure 14 (b) shows the resistance response results under different push positions; Figure 14 (c) shows the resistance response results at different push positions and push distances; Figure 14 (d) shows the response time results at different push positions and push distances;

[0050] Figure 15 Schematic diagram of surface morphology recognition and resistance response diagram, Figure 15 (a) Local diagram of the sensor array; Figure 15 (b) is the effect of resistance d = 1mm; Figure 15 (c) is the effect of resistance value d = 2mm;

[0051] Figure 16 The resistance response test results of the ciliary array are shown in Figure 2. Figure 16 (a) to (c) are schematic diagrams of bending; Figure 16 (b) to (f) are the array resistance response results;

[0052] Figure 17 Schematic diagram and actual picture of the ciliary sensing unit under different curvatures. Figure 17 (a) is the radius of curvature ∞; Figure 17 (b) in the figure has a curvature radius of 10 mm; Figure 17 (c) in the figure has a curvature radius of 8 mm; Figure 17 (d) in the figure is the curvature radius of 6 mm;

[0053] Figure 18 is the resistance response test result of the curved array unit, Figure 18 (a) shows the drift of the resistance response curve under different surface environments; Figure 18 (b) shows the resistance response results under different surface environments;

[0054] Figure 19 Schematic diagram of surface morphology recognition and resistance response diagram, Figure 19 (a) is a schematic diagram of the triangular surface morphology; Figure 19 (b) is a schematic diagram of the semicircular surface morphology; Figure 19 (c) is a schematic diagram of the square surface morphology; Figure 19 (d) is the triangle surface topography resistance measurement curve; Figure 19 (e) is the semicircular surface topography resistance measurement curve; Figure 19 (f) Square surface topography resistance measurement curve;

[0055] Figure 20 This is a schematic diagram of establishing a raised Braille structure (hemispherical structure) on a flat panel. Figure 20 (a) is a real picture of the Braille board; Figure 20 (b) is the 3D model of the Braille board;

[0056] Figure 21 For "hit" Braille recognition and sensor signal response, Figure 21 (a) is a schematic diagram of Braille recognition; Figure 21 (b) shows the signal response of the sensing unit; Figure 21 (c) in the figure is the Braille table for “hit”;

[0057] Figure 22 For "hello" Braille recognition and sensor signal response, Figure 22 (a) is a schematic diagram of Braille recognition; Figure 22 (b) shows the signal response of the sensing unit; Figure 22 (c) is the Braille table for "hello";

[0058] Figure 23 This is a schematic diagram of the airflow detection of a rigid structure. Figure 23 (a) is a physical picture of the embedded rigid structure; Figure 23 (b) is a schematic diagram of the embedded rigid structure; Figure 23 (c) is a schematic diagram of airflow detection;

[0059] Figure 24 Optimize the selection of rigid structure dimensions, Figure 24 (a) shows the effect of length ratio on resistance response; Figure 24 (b) shows the effect of the value of a on the resistance response.

[0060] Figure 25 To test the performance of ciliary electronic skin, Figure 25 (a) to (e) are the actual pictures and response results of the multi-touch and airflow sensing of the ciliary electronic skin; Figure 25 (f) to (j) are the actual pictures and response results of the ciliary electronic skin sliding sensing and airflow sensing. DETAILED DESCRIPTION

[0061] The present invention provides a bionic ciliary electronic skin, comprising a flexible substrate, a flexible circuit layer arranged on the surface of the flexible substrate, and a flexible ciliary layer arranged on the surface of the flexible circuit layer;

[0062] The flexible circuit layer is provided with a two-dimensional circuit array, the two-dimensional circuit array is formed by arranging a two-dimensional circuit unit array, and the two-dimensional circuit unit is formed by a two-dimensional circuit microchannel;

[0063] The flexible ciliary layer is provided with a ciliary sensing array, wherein the ciliary sensing array is formed by arranging ciliary sensing units in an array, and the ciliary sensing units are three-dimensional ciliary structures;

[0064] The orthographic projection area of ​​the ciliary sensing unit on the surface of the flexible substrate at least partially overlaps with the orthographic projection area of ​​the two-dimensional circuit unit on the surface of the flexible substrate;

[0065] It also includes liquid metal filled in the two-dimensional circuit microchannel.

[0066] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0067] The bionic ciliary electronic skin provided by the present invention includes a flexible substrate. In the present invention, the material of the flexible substrate is preferably polydimethylsiloxane (PDMS). The thickness of the flexible substrate is preferably 0.5 mm.

[0068] The bionic ciliary electronic skin provided by the present invention includes a flexible circuit layer arranged on the surface of the flexible substrate. In the present invention, the flexible circuit layer is provided with a two-dimensional circuit array, the two-dimensional circuit array is formed by arranging a two-dimensional circuit unit array, and the two-dimensional circuit unit is formed by a two-dimensional circuit microchannel. In the present invention, the shape of the two-dimensional circuit unit is preferably a square spiral pattern formed by the two-dimensional circuit microchannel (such as Figure 2 or Figure 5 The side length of the two-dimensional circuit unit is 3 mm, and the circuit density is 32.0 cm -1 The spacing between two adjacent two-dimensional line units is 1 to 2 mm. The spacing between two adjacent two-dimensional line units is the direct distance between the adjacent edges of the two adjacent two-dimensional line units (such as Figure 15 As shown in (a) in FIG). The cross-sectional shape of the two-dimensional circuit microchannel is 0.1×0.1 mm 2 In the present invention, the size of the sensing area of ​​the two-dimensional line unit is preferably 3×3 mm 2 The material of the flexible circuit layer is preferably platinum-catalyzed silicone rubber (Ecoflex). The thickness of the flexible circuit layer is preferably 0.5 mm.

[0069] In the present invention, the two-dimensional circuit array is arranged on the surface of the flexible circuit layer that contacts the flexible substrate. The flexible substrate encapsulates one surface of the two-dimensional circuit microchannel in the longitudinal direction to obtain a completed two-dimensional circuit microchannel.

[0070] The bionic ciliary electronic skin provided by the present invention includes a flexible ciliary layer arranged on the surface of the flexible circuit layer. In the present invention, the flexible ciliary layer is provided with a ciliary sensor array, and the ciliary sensor array is formed by an array of ciliary sensor units, and the ciliary sensor units are three-dimensional ciliary structures. The shape of the three-dimensional ciliary structure is a solid cone, and the bottom diameter (D) of the three-dimensional ciliary structure is preferably 0.8 to 2 mm, and more preferably 0.8 mm, 1 mm, 1.5 mm or 2 mm (such as Figure 7 (a)); height (H) is preferably 2.5 to 4.5 mm, specifically preferably 2.5 mm, 3.5 mm or 4.5 mm (such as Figure 7 (a) in the above text. The flexible ciliary layer is preferably made of platinum-catalyzed silicone rubber (Ecoflex). The thickness of the flexible ciliary layer is preferably 0.5 mm. The flexible ciliary layer includes a ciliary support layer and a ciliary sensing unit located on the surface of the ciliary support layer. The thickness of the flexible ciliary layer is the thickness of the ciliary support layer.

[0071] In the present invention, the orthographic projection area of ​​the ciliary sensor unit on the surface of the flexible substrate is at least partially overlapped with the orthographic projection area of ​​the two-dimensional circuit unit on the surface of the flexible substrate. In a specific embodiment of the present invention, the center of one of the two-dimensional circuit units is overlapped with the center of one of the ciliary sensor units. The bottom diameter of the three-dimensional ciliary structure is preferably less than the side length of the two-dimensional circuit unit (e.g., Figure 1 (c) and Figure 5 (left image in ).

[0072] In the present invention, since Ecoflex has strong plastic tensile properties but low tensile strength, PDMS has a certain stiffness to complement Ecoflex. At the same time, Ecoflex's excellent stretchability (elongation at break 600%) also makes up for the weaker stretchability of PDMS (140%). The "Ecoflex to PDMS" bionic ciliary electronic skin obtained by bonding the two has the advantages of both (σb = 1.92 MPa, elongation at break 400%). Therefore, the subsequent circuit tensile fatigue test can take 300% strain as the tensile limit.

[0073] The bionic ciliary electronic skin provided by the present invention further comprises liquid metal filled in the two-dimensional circuit microchannel. In the present invention, the liquid metal is preferably oxidized EGaIn, and the surface tension of the oxidized EGaIn is preferably 517mN·m -1 The viscosity is preferably 2.3×10 4 mPa·s.

[0074] In the present invention, the two-dimensional circuit unit and the liquid metal filled in the two-dimensional circuit microchannel together constitute the two-dimensional sensing unit of the flexible circuit layer. In the present invention, the size of the two-dimensional sensing unit is preferably 3×3 mm. 2 .

[0075] This invention reduces the surface tension of EGaIn by modifying its oxidation method. The goal of this oxidation is to improve the performance of millimeter-scale electronic skin, making it more stable and reliable. This oxidation modification provides a more feasible solution for filling small channels, ensuring circuit reliability and stability.

[0076] In the present invention, the method for preparing the oxidized EGaIn preferably comprises the following steps:

[0077] The EGaIn, an inorganic strong base, and water are mixed for oxidation to obtain oxidized EGaIn. In the present invention, the inorganic strong base is preferably NaOH, and the mass ratio of the EGaIn to the inorganic strong base is preferably 24:0.16. The mixing preferably includes: dissolving the inorganic strong base in water to obtain a pentavalent strong base aqueous solution. Then, the EGaIn and the inorganic strong base aqueous solution are mixed. The molar concentration of the inorganic strong base aqueous solution is preferably 0.2 mol / L. The oxidation time is 2 to 6 hours, specifically preferably 2 hours, 4 hours, or 6 hours. The oxidation is carried out under stirring.

[0078] The present invention provides a method for preparing the bionic ciliary electronic skin described in the above technical solution, comprising the following steps:

[0079] The cilia template, circuit template and blank base plate are obtained by 3D printing;

[0080] Using the template method, a flexible ciliary layer, a flexible circuit layer, and an uncured flexible substrate were prepared using a ciliary template, a circuit template, and a blank substrate, respectively.

[0081] The flexible cilia layer, the flexible circuit layer and the flexible substrate in an uncured state are sequentially stacked and bonded to obtain a semi-finished product;

[0082] Liquid metal is injected into the two-dimensional circuit microchannel of the semi-finished product to obtain the bionic ciliary electronic skin.

[0083] The present invention uses 3D printing to produce a ciliary template, a circuit template, and a blank baseplate. The present invention has no particular requirements for the specific implementation of the 3D printing. The frame height of the ciliary template, circuit template, and blank baseplate is preferably 0.5 mm.

[0084] In the present invention, the raw material used for the 3D printing is preferably a photosensitive resin. The 3D printing directly obtains an initial state cilia template or an initial state circuit template; after obtaining the initial state cilia template, the present invention preferably further comprises: washing, photocuring and hydrophobicizing the initial state cilia template in sequence to obtain the cilia template. The specific implementation method of the washing is preferably: soaking the initial state cilia template in an anti-poisoning agent for 5 minutes to remove residual resin, and then washing with anhydrous ethanol to remove the anti-poisoning agent. The photocuring is preferably ultraviolet curing. The photocuring time is ≥24h. In order to further improve the accuracy of cilia demolding, the present invention performs a hydrophobic treatment on the surface of the cilia template after photocuring. The specific implementation method of the hydrophobic treatment is preferably: first, rinse the template surface with alcohol, and then perform plasma shock in a plasma shock box for 10 minutes, repeat three times, and then normal demolding can be performed.

[0085] After obtaining the initial circuit template, the present invention preferably further comprises: sequentially washing and photocuring the initial circuit template to obtain the circuit template. A preferred embodiment of the washing step comprises soaking the initial cilia template in an anti-poisoning agent for 5 minutes to remove residual resin, followed by washing with anhydrous ethanol to remove the anti-poisoning agent. The photocuring step is preferably ultraviolet light curing. The photocuring time is ≥ 24 hours.

[0086] After obtaining the ciliary template, circuit template and blank base plate, the present invention adopts a template method to prepare a flexible ciliary layer, a flexible circuit layer and a flexible substrate in an uncured state respectively using the ciliary template, circuit template and blank base plate.

[0087] In the present invention, the template method for preparing a flexible hair layer or flexible circuit layer preferably includes the following steps: mixing components A and B of platinum-catalyzed silicone rubber, applying the mixture to the hair template or circuit template, and then thermally curing and demolding to obtain the flexible hair layer or flexible circuit layer. In the present invention, the mass ratio of components A to B is preferably 1:1. The coating thickness is preferably 0.5 mm; the thermal curing temperature is preferably 45°C, and the curing time is preferably 20 minutes.

[0088] In the present invention, the template method for preparing an uncured flexible substrate preferably includes the following steps: mixing a base component of polydimethylsiloxane with a curing agent, coating the mixture on a blank substrate, and then removing the mixture from the mold after thermal curing to obtain an uncured flexible substrate. In the present invention, the mass ratio of the base component to the curing agent is preferably 10:1. The coating thickness is preferably 0.5 mm, and the thermal curing temperature is preferably 45°C, and the curing time is preferably 2.5 hours.

[0089] After obtaining the flexible cilia layer, the flexible circuit layer, and the incompletely cured flexible substrate, the present invention sequentially stacks the flexible cilia layer, the flexible circuit layer, and the incompletely cured flexible substrate and then bonds them together to obtain a semi-finished product. In the present invention, the bonding temperature is preferably 45°C and the bonding time is preferably ≥3 hours.

[0090] After obtaining the semi-finished product, the present invention injects liquid metal into the two-dimensional circuit microchannels of the semi-finished product to obtain the bionic ciliary electronic skin. In the present invention, the injection is preferably performed using a small syringe. After the liquid metal is injected, the present invention preferably leads a metal wire out of the port and seals it with strong glue to obtain the bionic ciliary electronic skin. The metal wire is preferably Cu wire.

[0091] The present invention provides the application of the bionic ciliary electronic skin described in the above technical solution or the bionic ciliary electronic skin prepared by the preparation method described in the above technical solution in constructing bionic robots, preparing intelligent prostheses or preparing multi-dimensional detection equipment.

[0092] In specific embodiments of the present application, the bionic cilia electronic skin is particularly applied to surface topography recognition, Braille reading and preparation of air flow detection equipment.

[0093] In the present application, when the bionic cilia is applied to preparation of air flow detection equipment, the present application preferably sets an embedded rigid structure (such as Figure 1 (e)) at the top end of the cilia sensing unit of the bionic cilia electronic skin, and the embedded rigid structure is arranged at the top end of the three-dimensional cilia structure. In this way, the sensing ability of the bionic cilia electronic skin to air flow is improved. The embedded rigid structure comprises a first component and a second component, the first component and the second component are fixedly connected, one end of the second component is fixed to the top end of the three-dimensional cilia structure and is inserted into the inside of the top end of the three-dimensional cilia structure, the first component is arranged at the other end of the second component away from the top end of the three-dimensional cilia structure, and the first component is in contact with air flow, thereby improving the sensing ability of the bionic cilia electronic skin to air flow.

[0094] The first component is a square with a side length of a, and the second component is a rectangle with a long side of L1+L2-a.

[0095] In order to further improve the sensitivity of the millimeter-level cilia sensing unit and realize the detection function of air flow, the present application preferably modifies the cilia structure, and the modification is performed by using an embedded rigid structure. The structural schematic diagram of the embedded rigid structure is shown in Figure 23 (a) and (b). The present application first designs the rigid structure by Solidworks, designs the size parameters a, L1 and L2 of the embedded rigid structure, and prints the rigid structure with different size parameters by using a BMF S130 precision light curing printer. In order to adapt to the rigid structure, the cilia template needs to be improved. The cilia template is designed to have a convex groove structure by Solidworks to adapt to the rigid structure, and the improved cilia template is printed by using a BMF S130 precision photosensitive resin 3D printer; in order to meet the subsequent curing requirements, the improved cilia template is soaked in an anti-poisoning agent for 5 min to remove residual resin, then washed with anhydrous ethanol to remove the anti-poisoning agent, and finally irradiated in a ultraviolet curing box for more than 24 h to realize further curing; in order to further improve the cilia demolding precision, the surface of the cilia template needs to be treated by hydrophobic treatment. First, rinse the template surface with alcohol, then perform plasma impact in a plasma impact box for 10 min, repeat three times, and then normal demolding can be performed.

[0096] After combining the embedded rigid structure with the optimized cilia, the embedded rigid structure with different structural sizes was changed and placed under airflow of different wind speeds for testing. The output response of the millimeter-level cilia sensor unit was detected using a multimeter, and linear fitting was performed to compare the rigid structure with the best performance.

[0097] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0098] The materials used in the following examples are EGaIn liquid metal with a melting point of 16°C, platinum-catalyzed silicone rubber (Ecoflex-0030), polydimethylsiloxane (PDMS), ABS (Acrylonitrile Butadiene Styrene), PLA (Polylactic acid), 0.05 mm diameter copper wire (Cu), acetone, anhydrous ethanol, sodium hydroxide (NaOH), BIO photosensitive resin, an anti-poisoning agent, and deionized water. The materials used, their purity, and manufacturer information are shown in Table 1.

[0099] Table 1 Main experimental materials and specifications

[0100] Drug name grade Manufacturer EGaIn liquid metal - Changge Shuochen Metal Co., Ltd. Platinum-catalyzed silicone rubber - American Smooth-on Polydimethylsiloxane - Dow Corning ABS plastic - Beijing Huitianwei Technology Co., Ltd. PLA plastic - Beijing Huitianwei Technology Co., Ltd. copper wire - Ruiqi Polymer Materials Technology Co., Ltd. acetone analytically pure Xilong Science Co., Ltd. Anhydrous ethanol analytically pure Tianjin Best Chemical Co., Ltd. Sodium hydroxide analytically pure Tianjin Damao Chemical Reagent Factory BIO photosensitive resin - Chongqing Mofang Precision Technology Co., Ltd. Anti-poisoning agent - Chongqing Mofang Precision Technology Co., Ltd. Deionized water analytically pure Pure water preparation

[0101] In the following examples, the preparation of centimeter- and millimeter-scale EGaIn modular flexible electronic skins using the internal cleaning sacrificial template method and template removal method primarily involved a melt extrusion 3D printer, an ultra-precision photosensitive resin 3D printer, a vacuum drying oven, a UV curing chamber, a contact angle meter, an electronic analytical balance, an ultrasonic cleaning machine, a magnetic stirrer, a water purifier, and a syringe. Static touch and dynamic sliding performance testing of the two modular flexible electronic skins primarily involved an optical microscope, a function signal generator, a power amplifier, an oscillator, a Keithley multimeter, and a stepper stretching platform.

[0102] Table 2 Experimental equipment and instruments

[0103]

[0104]

[0105] The specific preparation process of the two-dimensional electronic skin and ciliary electronic skin in the following embodiments is as follows: Figure 1 shown.

[0106] Example 1

[0107] The original EGaIn was mixed with a concentration of 0.2 mol·L -1 of NaOH solution to obtain a mixed solution, wherein the amount of EGaIn used is 24g, the amount of NaOH solution used is 20mL, and the oxides in the mixed solution are removed by ultrasonic cleaning for 10min. A magnet is added and stirred at a speed of 200r / min to oxidize it. Unoxidized EGaIn and EGaIn oxidized for 2h, 4h, and 6h are extracted respectively, and their surface tension and contact angle on Ecoflex and PDMS are tested using a contact angle meter, and the viscosity of EGaIn is measured using a viscometer. A sensing circuit with a line width of 0.1mm and a length of 8mm is prepared by a demolding method as a sensor sample for conductivity measurement, and the resistance of the sensor is measured using a multimeter DMM7510, and the conductivity is obtained by calculation.

[0108] In order to ensure the best liquid metal oxidation effect, the viscosity of EGaIn was measured by viscometer during oxidation. Before the oxidation experiment, 20g of EGaIn was taken to measure its viscosity. Then, 24g of each of four groups of EGaIn was placed in a beaker and 0.2mol·L was added. -1 The samples were stirred with a magnetic stirrer at a speed of 200 r / min for oxidation. The viscosity of the first group was measured after 2 h of oxidation, the viscosity of the second group was measured after 4 h of oxidation, the viscosity of the third group was measured after 6 h of oxidation, and the viscosity of the third group was measured after 8 h of oxidation.

[0109] When EGaIn is used as a filling material in small-sized channels, a series of problems will arise. EGaIn has a high surface tension of about 624mN·m -1 Due to its poor wettability with the substrate material, it is difficult to form a stable and reliable conductive path in the small-scale channel. Therefore, the circuit is often open. This phenomenon is as follows Figure 2 As shown. Figure 2 In the figure, the silver-white part represents the successfully filled liquid metal, while the red area indicates that the liquid metal shrinks to both sides, causing the circuit to be interrupted. Figure 2 The gray areas in the figure represent gallium oxide adhering to the inner walls of the channel. The high surface tension of EGaIn makes it susceptible to circuit interruption when filling small-scale channels. To overcome this problem, this embodiment oxidizes EGaIn to reduce its surface tension. This method aims to improve the performance of millimeter-scale electronic skin, making it more stable and reliable. This modification process provides a more feasible solution for filling small-scale channels, ensuring circuit reliability and stability.

[0110] In this example, the initial EGaIn is mixed with a NaOH solution and then ultrasonically cleaned to remove trace oxides that may have formed during manufacturing and transportation, ensuring that the EGaIn used subsequently maintains a consistent initial state. Subsequently, magnetic stirring is introduced for oxidation, causing a continuous oxidation reaction on the EGaIn surface to produce gallium oxide. Simultaneously, the generated gallium oxide is broken up and stirred, then incorporated into the EGaIn's internal structure. This results in a uniform interior containing dispersed gallium oxide particles, effectively reducing the EGaIn's surface tension.

[0111] The surface tension of EGaIn was measured at the initial stage and during the subsequent oxidation process using the hanging drop method. Figure 3 The results are shown in (a). After measurement, the surface tension of EGaIn at the initial moment is about 585mN·m -1 With the increase of oxidation time, the surface tension of EGaIn continued to decrease. After stirring for 6 hours, the surface tension decreased to 517mN·m -1 Continuing to stir the mixture resulted in excessive oxidation, and the EGaIn became a clumping slurry, almost losing its fluidity and making it difficult for the magnet to continue stirring. This demonstrates that controlled oxidation achieved through stirring can effectively reduce the surface tension of EGaIn.

[0112] In order to further demonstrate the improvement of wettability and adhesion properties by oxidation, this example first measured the change of EGaIn viscosity with the oxidation process, such as Figure 3 As shown in (b), the viscosity of EGaIn gradually increases with stirring. In the 2-4h stage, the rising speed is relatively slow. When stirring reaches 6h, the viscosity increases significantly and the fluidity is poor. The viscosity increases from the initial 1.2×10 4 mPa·s increased to 2.3×10 4 mPa·s. Then the contact angle changes of EGaIn on Ecoflex and PDMS were measured. Figure 3 As shown in Figures (c) and (d), the contact angles of unoxidized EGaIn on Ecoflex and PDMS are 140.9° and 141.2°, respectively. With the continuous oxidation during stirring, the contact angles show a clear downward trend. After 6 hours of stirring, the contact angles drop to 108.1° and 109.3°, respectively.

[0113] In order to further intuitively and quantitatively verify the oxidation degree of EGaIn during the stirring process, EGaIn was weighed and measured during the stirring process: 40g of EGaIn treated with NaOH was taken for magnetic stirring oxidation, and it was weighed and measured at regular intervals to calculate the relationship between the oxidation mass fraction of EGaIn and the stirring time, as shown in the following example: Figure 4As shown in (a), it can be seen that with the increase of stirring time, the oxidation mass fraction of EGaIn increases linearly, and the oxidation mass increases by 0.1% at 6h. The conductivity of EGaIn with different stirring times is then measured, as shown in Figure 4 As shown in (b), it can be found that the conductivity of EGaIn changes little when the stirring time is 2 to 4 hours, but increases slightly. When the stirring time is increased to 6 hours, its conductivity increases significantly, from the initial 3.6×10 6 S / m increased to 4.4×10 6 S / m. Oxidized EGaIn significantly improves its wettability and adhesion on Ecoflex and PDMS surfaces. However, while prolonged oxidation improves wettability, it also increases EGaIn's overall viscosity and deteriorates its fluidity, almost turning it into a slurry. Therefore, without compromising electrical performance, the millimeter-scale electronic skin prepared in Examples 2 and 3 below uses EGaIn oxidized for 4 hours to fill the circuit microchannels.

[0114] Example 2: Preparation of two-dimensional electronic skin

[0115] In this embodiment, the two-dimensional electronic skin is prepared by using the oxidized EGaIn prepared in Example 1 as the conductive functional material through a template removal method. The main steps of preparing the electronic skin are as follows:

[0116] (1) Complete the small-scale circuit graphic design in the 3D design software Solidworks, where the size of the sensing area is 3×3mm 2 , the side length of a single unit is 3mm, and the line density is 32.0cm -1 , the cross-section of the line is 0.1×0.1mm 2 The distances d and d between two adjacent line sensing units are 1mm and 2mm respectively. The template frame height is 0.5mm. The total size of the template plane is 30×30mm. 2 ;

[0117] (2) Use a precision photosensitive resin 3D printer (Mofang Precision P150) to print the designed circuit pattern and the blank base plate (the base plate frame height is 0.5mm and the bottom area is 40×8mm) 2 ) Printing out with photosensitive resin to construct a resin template, including a circuit template and a blank base plate;

[0118] (3) To meet the subsequent curing requirements, soak the circuit template in an anti-poisoning agent for 5 minutes to remove the residual resin, then clean it with anhydrous ethanol to remove the anti-poisoning agent, and finally irradiate it in a UV curing box for more than 24 hours to achieve further curing;

[0119] (4) The A and B components of Ecoflex were fully mixed in a mass ratio of 1:1 and then coated on the circuit template. The coating thickness was controlled to 0.5 mm by a spin coater and placed in a drying oven at 45°C for 30 minutes for curing. The cured Ecoflex was peeled off from the circuit template. In this way, the circuit pattern in the circuit template was successfully transferred to the lower surface of the Ecoflex flexible substrate to obtain a flexible circuit layer.

[0120] (5) PDMS was fully mixed in a mass ratio of 10:1 between the basic component and the curing agent and then coated on a blank substrate with a coating thickness of 0.5 mm. The substrate was then placed in a drying oven and cured at 45° C. for about two and a half hours to semi-cured the PDMS. A PDMS film in a semi-cured state was obtained.

[0121] (6) Laminating the flexible circuit layer obtained by peeling the cured Ecoflex to the semi-cured PDMS film, and curing them in a drying oven at 45°C for more than three hours to achieve bonding;

[0122] (7) Use a small syringe to draw the oxidized EGaIn prepared in Example 1 and inject it into the circuit channel of the flexible substrate. Then use a Cu wire to lead out the port and seal it with strong glue to obtain a two-dimensional electronic skin.

[0123] Example 3: Preparation of ciliary electronic skin

[0124] In this example, the ciliary electronic skin is manufactured using 3D printing technology based on the two-dimensional electronic skin to create a ciliary structure. The oxidized EGaIn prepared in Example 1 is used as the conductive functional material and is prepared by template removal. The main steps for preparing the ciliary electronic skin are as follows:

[0125] (1) Complete the small-scale circuit graphic design in the 3D design software Solidworks, where the size of the circuit sensing area is 3×3mm 2 , the side length of a single unit is 3mm, and the line density is 32.0cm -1 , the cross-section of the line is 0.1×0.1mm 2 The distances d and d between two adjacent line sensing units are 1mm and 2mm respectively. The template frame height is 0.5mm. The total size of the template plane is 30×30mm. 2 At the same time, the design of the cilia template was completed, with four parameters for the cilia bottom diameter D = 0.8mm, 1mm, 1.5mm, and 2mm, three different parameters for the cilia length H = 2.5mm, 3.5mm, and 4.5mm, and the template frame height was 0.5mm;

[0126] (2) Use a precision photosensitive resin 3D printer (Mofang Precision P150) to print the designed circuit pattern, cilia template, and blank base plate (the base plate frame height is 0.5mm and the bottom area is 40×8mm). 2 ) is printed out with photosensitive resin to construct a resin template, including a cilia template, a circuit template and a blank base plate.

[0127] (3) To meet the subsequent curing requirements, the circuit template and the cilia template were immersed in an anti-poisoning agent for 5 minutes to remove the residual resin, and then washed with anhydrous ethanol to remove the anti-poisoning agent, and finally irradiated in a UV curing box for more than 24 hours to achieve further curing;

[0128] (4) In order to further improve the accuracy of ciliary demolding, the surface of the ciliary template needs to be hydrophobic. First, rinse the template surface with alcohol, and then perform plasma shock in a plasma shock box for 10 minutes, repeat three times, and then normal demolding can be performed.

[0129] (5) The A and B components of Ecoflex were fully mixed in a mass ratio of 1:1 and then coated on the circuit template and the cilia template with a coating thickness of 0.5 mm. The mixture was placed in a drying oven and cured at 45°C for 20 minutes. The cured Ecoflex was peeled off from the cilia template and the circuit template. In this way, the circuit patterns in the cilia template and the circuit template were successfully transferred to the lower surface of the Ecoflex flexible substrate, thereby obtaining a flexible circuit layer and a flexible cilia layer.

[0130] (6) PDMS was fully mixed in a mass ratio of 10:1 between the basic component and the curing agent and then coated on a blank substrate with a coating thickness of 0.5 mm. The substrate was then placed in a drying oven and cured at 45° C. for about two and a half hours to semi-cured the PDMS. A PDMS film in a semi-cured state was obtained.

[0131] (7) The flexible circuit layer and flexible cilia layer obtained by peeling the cured circuit Ecoflex and cilia Ecoflex are laminated together with the semi-cured PDMS film, and then placed in a drying oven at 45°C for more than three hours to achieve bonding;

[0132] (8) Use a small syringe to absorb the oxidized EGaIn prepared in Example 1 and inject it into the circuit channel of the flexible substrate. Then use a Cu wire to lead out the port and seal it with strong glue to obtain a modular millimeter-scale ciliary electronic skin.

[0133] Example 4: Performance Characterization of Two-Dimensional Sensing Unit

[0134] For the millimeter-scale electronic skin in which the microchannels were prepared by the template removal method and filled with oxidized EGaIn in Example 2, a single sensing unit was observed under a low-power microscope. The results are as follows: Figure 5 As shown. The size of a single sensing area is 3×3mm 2 , EGaIn line density is 32.0cm -1 The width of the liquid metal circuit channel is 0.1mm. Furthermore, observations under a light microscope show that the circuit patterns of individual two-dimensional sensing units are more refined and regular. The controlled oxidation of EGaIn also demonstrates superior filling of the sensing unit, with no circuit shrinkage, EGaIn adhesion to the inner wall of the circuit, or open circuits.

[0135] In this experiment, a weight loading method was used to measure the resistance response of a single two-dimensional sensor unit prepared in Example 2 under various loading conditions with the help of a multimeter. During loading, a 3×3 mm thick plate was placed on the unit to ensure uniform force. 2 When measuring the linear sensing range and response time of the sensor unit.

[0136] The pressure resolution of the single two-dimensional sensing unit prepared in Example 2 in response to pressure load was further determined by weight loading experiments. The first weight applied was 10 g (11000 Pa), and the mass of the accumulated weights was then reduced in sequence until the sensing unit showed no response. The step-by-step loading curve was obtained as shown in Figure 2. Figure 6 As shown in (a) of the figure. Pressures in the range of 55-11000 Pa produce a significant resistance response in the sensor unit. A zoomed-in view of the purple and orange areas also illustrates the resistance change of the sensor unit at pressures of 10 Pa and 5 Pa. When the pressure is 10 Pa, the resistance increment of a single sensor unit is approximately 0.13 mΩ; when the pressure is 5 Pa, the resistance signal of the sensor unit does not change significantly. Therefore, this millimeter-scale sensor unit can resolve a pressure load of at least 10 Pa within its linear sensing range, meaning that the pressure resolution of the two-dimensional sensor unit is 10 Pa (0.01 g).

[0137] At the same time, the linear sensing range of a single two-dimensional electronic skin sensing unit was further determined, and the Figure 6 The results are shown in (b) of Figure 1. The critical pressure for the sensor unit to produce a resistance response is 10 Pa, and the critical pressure for EGaIn leakage is 22,000 Pa. For the six data points in the range of 10-22,000 Pa, the correlation coefficient R² of the linear fit also exceeds 99%, indicating that the resistance response of the two-dimensional sensor unit exhibits a good linear relationship with the pressure load. Therefore, the linear sensing range of the two-dimensional sensor unit is 10-22,000 Pa (0.01-20 g).

[0138] Further extract the response time of a single sensor unit under these six pressure conditions and obtain Figure 6 The results are shown in (c) of Figure 1. For pressures ranging from 10 to 22,000 Pa, the response time gradually increases from 0.05 to 0.14 seconds as the pressure load increases. For the resistance response under higher pressure loads, a pressure load of 22,000 Pa only requires 0.14 seconds. Therefore, this two-dimensional sensing unit has an extremely fast response speed to pressure loads.

[0139] in, Figure 6 (d) and (e) in Figure 6 The two illustrations in (a) show the resistance change under a pressure of 5 Pa. The overall coordinates of the illustrations are Figure 6 The vertical coordinates of (a) are the same.

[0140] Example 5: Study on the influence of single cilium preparation and parameters on performance

[0141] In Example 3, 12 types of single ciliary structures with different structural parameters were prepared by demoulding method. Figure 7 As shown in (a), four parameters of the ciliary base diameter D = 0.8mm, 1mm, 1.5mm, and 2mm, and three different parameters of the ciliary length H = 2.5mm, 3.5mm, and 4.5mm were selected. Figure 7 As shown in (b) and (c), the ciliary structure prepared by the demolding method is placed under a light microscope for observation. It can be clearly observed that the shape and size of the cilia are basically consistent with the design, and the bottom connection is also very smooth. In order to make the subsequent detection of the cilia bending performance more intuitive and convenient, four bending degrees (15°, 30°, 45°, and 60°) are specified. Figure 7 As shown in (d) in .

[0142] The single-ciliary liquid metal sensor units with 12 parameters prepared in Example 3 were subjected to bending tests at 15°, 30°, 45°, and 60°, and the response resistance results were Figure 8As shown in Figure 2, three sets of response resistance versus ciliary diameter D curves are plotted for ciliary lengths H = 2.5 mm, 3.5 mm, and 4.5 mm. Overall, the response resistance of the ciliary sensor increases with increasing bending angle, and the slope of the curve increases significantly when the bending angle is greater than or equal to 30°. This indicates that the response resistance per unit bending angle increases as the bending angle increases. Therefore, the subsequent linear fit of the response resistance ΔR for bending angle θ needs to consider the trigonometric function of θ. For the same ciliary length, the response resistance of the ciliary sensor gradually increases with increasing ciliary base diameter D. For base diameters of 0.8 mm and 1 mm, the response resistance is very small, and the linear changes with bending angle are basically the same for both. When the ciliary base diameter is greater than 1 mm, that is, 1.5 mm and 2 mm, the slope of the response resistance curve with increasing bending angle is significantly greater than that for ciliary base diameters less than or equal to 1 mm, and the slope is maximum when the ciliary base diameter is 2 mm. Selecting a cilia base diameter of D = 2 mm, and comparing the effect of cilia length H on cilia sensing performance, we found that when the cilia length was 2.5 mm, the maximum response resistance was around 14 mΩ. When the cilia length increased to 3.5 mm, the maximum response resistance was around 19 mΩ. However, when the cilia length continued to increase to 4.5 mm, due to the increasing ratio of cilia length to cilia base diameter, the slight deformation of the cilia tip was insufficient to cause tangential deformation of the cilia base. Therefore, when the cilia base diameter was 0.8 mm and 1 mm, the response resistance was 0. Similarly, when the cilia diameter was 1.5 mm and 2 mm, the maximum resistance response was significantly lower than the previous two cases, at only 5 mΩ. Therefore, in terms of response resistance, the cilia structure with a cilia base diameter of D = 2 mm and a cilia length of H = 3.5 mm was the best.

[0143] Response time is also an important indicator for measuring the sensitivity performance of sensors. The 12 parameters of the ciliary liquid metal sensor units prepared in Example 3 above were subjected to bending tests at 15°, 30°, 45°, and 60°. The response time results were Figure 9 As shown in the figure, the response time increases gradually with the increase of the ciliary bending angle, but the overall maximum response time does not exceed 0.42s. When the ciliary length is long (H = 4.5mm) ( Figure 9 (c) in the figure), for the two cases where the diameter of the cilia bottom surface is less than or equal to 1 mm, H / D is large, the deformation recovery speed is relatively slow, and therefore the response time is long; when the cilia length is short (H = 2.5 mm) ( Figure 9 (a) in the figure, the response time of the four bottom diameters is not much different. If we continue to increase the ciliary length to the data of the ciliary length of 3.5 mm just discussed, as shown in the figure below: Figure 9(b) and the response time is in the acceptable range when it is no more than 0.4 s, and the maximum response time of the four bottom diameter cilia structures is not much different (about 0.25 s). Therefore, the cilia structure with a bottom diameter D = 2 mm and a cilia length H = 3.5 mm is also a suitable choice in terms of the response time.

[0144] The response resistance and the response time of the cilia structure are detected respectively, and the three-factor three-dimensional image of the resistance response and the response time is further drawn based on the comprehensive data, so as to more intuitively and clearly select a suitable cilia structure. As shown in Figure 10 , it can be seen that the cilia structures with a bottom diameter D = 2 mm and a cilia length H = 3.5 mm and H = 2.5 mm have excellent resistance response capability. In combination with the analysis of the specific structure size of the cilia, when the cilia length H = 2.5 mm, the appearance structure of the cilia is more inclined to a square cone, and it is not as accurate and convenient as the length H = 3.5 mm for three-dimensional signal detection. In terms of the response time, as shown in Figure 11 , it has been discussed above, and therefore the cilia structure with a bottom diameter D = 2 mm and a cilia length H = 3.5 mm is selected.

[0145] Example 6: Performance characterization of a single-cilia sensing unit

[0146] Through the above cilia preparation and the related experiments of the influence of the cilia structure parameters on the performance, the optimal cilia structure parameters (D = 2 mm, H = 3.5 mm) are selected, and the performance of the millimeter-level single-cilia sensor under the parameters in Example 3 is further characterized.

[0147] Through the cilia bending experiment, the linearity of the millimeter-level cilia sensing unit to the bending load response is first determined. First, a bending action of 15° is applied, and then a bending action of 30°, 45° and 60° is applied every 10 s, and the response curve is as shown in Figure 12 (a). As shown in Figure 12 (a), the bending action in the range of 15°-60° can make the sensing unit produce a significant resistance response, and the local enlarged area also shows the resistance change of the sensing unit when the bending angle is 15°. When the bending angle is 15°, the resistance increment of the sensing unit is about 1.13 mΩ. Therefore, the millimeter-level cilia sensing unit can effectively respond to the bending action of 15°-60°, and is sufficient to sense and detect various signals in space. For the four groups of data points in the range of 15°-60°, the correlation coefficient R2 of the linear fitting is also more than 99% ( Figure 12In (b), the resistance response of the millimeter-scale ciliary sensor unit shows a good linear relationship with the bending pressure load. The fitting formula can be calculated by fitting the curve: ΔR = 5.13tanθ-0.433.

[0148] The response time of the sensor unit under these four bending pressure conditions is further extracted to obtain Figure 12 Results are shown in (c) of Figure 1. For bending pressure loading within the range of 15° to 60°, the response time gradually increases from 0.2s to 0.4s as the bending angle increases. For the resistance response at larger bending angles, a 60° bending pressure loading only requires 0.4s. Therefore, this millimeter-scale ciliary sensor unit exhibits extremely fast response to bending pressure loads.

[0149] The frequency sensing range of the ciliary sensor unit is further tested by controlling the push pin through the frequency generator to push the ciliary tip laterally, achieving the effect of continuous bending and recovery, so as to detect the frequency sensing range of the ciliary sensor unit. Figure 13 It can be seen that the ciliary sensing unit can effectively detect the driving frequency of 1Hz-25Hz and has excellent broadband detection capability.

[0150] For the conical structure of cilia, the performance of the cilia sensing unit was tested at different pushing positions and pushing distances. The test results are as follows Figure 14 shown.

[0151] First, the distance from the base, i.e. the bottom of the cone, is defined as the push position. Four different push positions (1mm, 2mm, 2.5mm, and 3.5mm) are set. The push frequency is controlled to 1Hz by a frequency generator, and the push distance is 1mm. The push position is controlled by a stepper motor, and signal detection is performed. The resistance response curve is shown in the figure. Figure 14 As shown in (a), it can be seen that the ciliary sensing unit can clearly detect different push positions, and the resistance responses of the four push positions are extracted, as shown in Figure 14 As shown in (b), as the push position gets closer to the bottom surface, the signal response of the ciliary sensor unit becomes larger and larger. When the push position is 1mm, its resistance response is about 9 times that of the push position at 3.5mm, which is 9.7mΩ. Further, the signal response of different push distances is explored, as shown in Figure 1. Figure 14As shown in (c), as the pushing distance increases, the overall slope of the broken line at the pushing position of 3.5mm and 2.5mm is basically constant. For the broken line at the pushing position of 2mm and 1mm, that is, the position closer to the bottom of the cone is pushed at different distances, when the pushing distance is less than 3mm, the broken line is relatively stable, and the slope is basically the same as that at the pushing position of 3.5mm and 2.5mm. When the pushing distance is greater than 3mm, the degree of cilia bending is greater, the tangential deformation of the bottom line part increases more, and the resistance response increases sharply, so the slope of the broken line increases. Figure 14 In (d), when the push position is 3.5mm and 2.5mm, the push distance has little effect on the response time, and the response time does not change much under the five push distances. When the push position is 2mm and 1mm, the response time gradually increases as the push distance increases. In summary, through the push position and push distance experiments, the study shows that the millimeter-scale ciliary sensor unit can detect objects at different depths and heights, and has excellent performance in detecting surface morphology and object shape.

[0152] Example 7: Selection of spacing and performance characterization of ciliary sensor arrays

[0153] In order to integrate multiple independent single ciliary sensor units into a 2×3 sensor array, it is necessary to determine the spacing d between two adjacent line sensor units through relevant experiments. When d is too large, the integration of the sensor array will inevitably decrease, and when d is too small, the load on one sensor unit will cause the resistance signal output by another adjacent sensor unit to be affected. Therefore, in Example 3, two sensor arrays with different spacings d were prepared, and d was 1mm and 2mm respectively. For these two sensor arrays (where the bottom diameter of the ciliary structure D = 2mm, and the ciliary length H = 3.5mm), a 45° bending load was applied to a sensor unit at the 45th and 53th seconds, and the resistance change of the adjacent sensor units was measured, and the result was obtained. Figure 15 The results shown in (b) and (c) are shown in Figure 2.

[0154] Comparison of the results shows that when d = 1 mm, loading adjacent sensor units causes a resistance change of approximately 0.4 mΩ in the sensor unit itself, while loading at d = 2 mm does not significantly change the resistance. Therefore, the spacing between adjacent sensor units should be determined to be 2 mm. Using 2 mm as the critical spacing between adjacent sensor units allows the fabrication of a 2×3 liquid metal flexible ciliary sensor array that does not interfere with each other.

[0155] The size of a single sensing unit of the millimeter-scale liquid metal flexible ciliary sensor array is 3×3mm. 2, with a side length of 3mm and a spacing of 2mm between adjacent sensing units in the same row and column, the flexible sensing array can therefore resolve two points at a minimum distance of 8mm. The liquid metal flexible electronic sensor array fabricated in this embodiment has achieved the same resolution as human skin on fingertips, nose tips, and other areas for two points in space.

[0156] The ciliary electronic skin product tested in the following embodiments has the following characteristics: the bottom diameter D of the ciliary structure is 2 mm, the ciliary length H is 3.5 mm, and the spacing between two adjacent line sensing units is 2 mm.

[0157] Example 8: Characterization of Multi-point Bending Touch Performance of Ciliary Electronic Skin

[0158] Through the above experiments and result comparison, we finally prepared a 2×3 liquid metal flexible ciliary sensor array (the bottom diameter of the ciliary structure D=2mm, the ciliary length H=3.5mm) without interfering with each other by using the above circuit pattern when d=2mm. In order to further characterize the sensing ability of the flexible ciliary sensor array to detect multi-point bending touch in real time, a multi-touch experiment was carried out using bent cilia. Figure 16 In (a), first, a small bending was performed on the two ciliary sensing units R1 and R2, and the two-point ciliary bending response results were obtained; Figure 16 In (b), by bending R1, R3, and R5 at the same angle, and also bending R2, R4, and R6 at the same angle, the two bending angles are different. The bending angle of the cilia in the right column is greater than that of the left column, and two columns of bending response results are obtained.

[0159] exist Figure 16 In (c), the three rows R1, R2, R3, R4 and R5, R6 were bent to different degrees, and the bending angles were increased in sequence to obtain the cilia bending response results of the three rows. Because there is a good linear relationship between the resistance increment of the cilia sensor unit and the sine of the bending angle, the bending angle of the cilia sensor unit can be calculated by the formula. Finally, we get Figure 16 The multi-point bending response histograms shown in (d), (e), and (f) are shown in the figure. The response results of each sensor unit under these three loading conditions can accurately determine whether the ciliary sensor unit is bent. Under the condition of ciliary bending, the angle of ciliary bending of each unit can also be identified through the response results ( Figure 16 (a), (b), and (c) in the figure, and the ciliary sensing units do not interfere with each other. This shows that with d = 2 mm as the critical spacing of the ciliary sensing array, a 2×3 liquid metal flexible ciliary sensing array with no mutual interference was successfully fabricated. This array can accurately identify ciliary bends and bending angles, and has good responsiveness to multi-point ciliary touch.

[0160] Example 9: Study on the influence of curved surfaces on the performance of ciliary electronic skin

[0161] The aforementioned static multi-point curved touch experiments have demonstrated the great potential of flexible ciliary sensor arrays in electronic skin applications. However, these experiments were conducted under flat conditions. However, actual electronic skin applications require a variety of complex curved surfaces. Therefore, it is necessary to examine the impact of curved surface environments on the sensing performance of ciliary arrays.

[0162] For this purpose, four different surface conditions of curvature radius R = ∞, R = 10mm, R = 8mm, and R = 6mm are set, such as Figure 17 shown.

[0163] The curved substrate beneath the sensor was printed using a HoriX400 with polylactic acid (PLA) plastic. The prepared ciliary array units were then placed on the corresponding curved substrates to create different curved environments. Under these conditions, the array sensor units were bent at four different angles: 15°, 30°, 45°, and 60°. The bending was applied every 10 seconds, and the resistance response was plotted. Figure 18 The results (a) in Figure 1 are shown. The changes in base resistance under different curved surface environments are compared. As the angle of the curved base increases, that is, as the curvature of the surface increases, the resistance of the sensor unit drifts to a certain extent, and the overall response curve shifts toward increasing resistance. Under the flat surface condition of R = ∞, the base resistance value is 637.6 mΩ, while under the curved surface condition of R = 6 mm, the base resistance value increases to 4.012 mΩ. Furthermore, the sensor unit's resistance response to the same pressure load under different curved surface conditions is compared.

[0164] pass Figure 18 As shown in (b), when the bending angle is the same, the resistance response (R / R0) data points of the sensor unit under different bending conditions are very concentrated, and the correlation coefficient R2 of the linear fitting is also over 99%, which shows that the millimeter-scale ciliary sensor unit can also perform good linear sensing in the range of 15°-60° in a curved environment.

[0165] Example 10: Application research of surface topography recognition

[0166] First, the required surface morphology structure is printed out by a light-curing 3D printer, and its cross-sectional view is as follows: Figure 19 (a), (b), and (c) are shown in the figure, which are large and small triangles, semicircles, and squares, respectively. The three printed surface topography structures are placed on a flat table. The movement speed of the ciliary sensor unit is controlled by a stepper motor. The ciliary sensor unit is pulled at a constant speed so that the tip of the ciliary structure contacts different surface topography structures. The resistance response curve is shown in the figure. Figure 19 (d), (e), and (f) in the figure.

[0167] It can be clearly seen that the ciliary sensor unit can effectively respond to surface topography of different shapes and sizes. For surface topography structures of different heights, the response size of 0.5mm height is about half that of 1mm height. At the same time, for triangles and semicircles with heights of 0.5mm and 1mm and spacing of 0.2mm, the type of surface topography can be analyzed from the curve shape. Similarly, for squares with heights of 0.5mm and 1mm and spacing of 0.3mm, the type of surface topography can also be easily analyzed. Therefore, the millimeter-level ciliary sensor unit is ready to identify complex surface topography and has excellent response capabilities.

[0168] Example 11: Braille Recognition Application Research

[0169] In Example 3, the single ciliary sensor unit was integrated into an array to successfully prepare a 2×3 mm ciliary electronic skin. Its multi-point bending touch capability was also verified. Based on the above characteristics, the present invention recognizes Braille. First, a Braille board model is drawn using Solidworks, and a Braille raised structure (hemispherical structure) is established on the board. A single Braille character is 6 raised structures of 2 columns and 3 rows. The spacing between columns is 2 mm, and the spacing between rows is 4 mm. The raised structure is a hemisphere with a radius of 0.5 mm. Figure 20 shown.

[0170] A Braille board was printed using a BMF S130 printer and placed on a flat table. The three cilia of the ciliary electronic skin were placed in contact with the Braille board. The sensor was moved horizontally so that the cilia slid over the hemispherical protrusions of the Braille board in sequence. The signal response of the ciliary sensor was detected using the multi-channel function of a multimeter. Figure 21 As shown in (a), sensor 1, sensor 2, and sensor 3 detect the first, second, and third lines of Braille, respectively, and their resistance signal responses are as follows: Figure 21 As shown in (b), the peak is the resistance response when the cilia are bent to the maximum extent. Every time the cilia pass through a Braille bump, the signal will have a waveform. Comparing the signal responses of the three sensors, according to Figure 21 The Braille comparison table (c) in the figure can clearly correspond to the signal response of each Braille letter. For example, for the first letter "h", the signal response of sensor unit 1 is "1", "0", the signal response of sensor unit 2 is "1", "1", and the signal response of sensor unit 3 is "0", "0". Comparing with the Braille comparison table on the right, it can be verified that the ciliary sensor array can accurately recognize Braille.

[0171] Accordingly, the present invention uses the ciliary electronic skin to detect the Braille characters of the long word "hello", such as Figure 22 It can also be seen that the ciliary electronic skin still has excellent recognition capabilities for a variety of Braille letters, and the signal performance is also very stable during the detection of long words.

[0172] Example 12: Characterization of dynamic sliding performance of millimeter-scale electronic skin

[0173] The present invention introduces a rigid structure and embeds it on the flexible ciliary base. In response to airflow, the rigid structure drives the ciliary base, thereby greatly improving the sensitivity of the ciliary sensing unit. First, the rigid structure is modeled and drawn using Solidworks, as shown in the figure. Figure 23 As shown in (a), the entire thickness of the embedded rigid structure is 1mm, and the embedded part below is a cylinder with a diameter of 1mm. a represents the side length of the square in the upper half of the rigid structure, L1 is the length of the rigid structure leaking out of the flexible base, and L2 is the length of the rigid structure embedded in the flexible base, where L1+L2=4.5mm. In order to select a suitable rigid structure, the present invention needs to optimize the selection, because the sizes of L1 and L2 have an impact on the degree of cilia bending. Increasing L1 can increase the force, and increasing L2 can increase the degree of bending of the flexible cilia base. Therefore, the present invention selects the rigid structure size that responds most obviously to the airflow by adjusting the ratio of L1 / L2 and the size of the side length a. Subsequently, the present invention used a BMFS130 light-curing 3D printer to print out four rigid structures with a=3mm, L1 / L2=2, 3.5, 5, and 8, and after interlocking them with the cilia base obtained by demolding, as shown in FIG. Figure 23 As shown in (b), it is placed in a controllable airflow speed environment and a multimeter is used for signal detection.

[0174] like Figure 24 As shown in (a), it can be seen that for different airflow velocities, the sensor has an obvious resistance response, and the resistance response size ΔR and the airflow velocity vw are fitted, and the fitting effect is good, and R2 is basically maintained at around 0.99, showing a good linear relationship. When the fixed side length a=3mm, as the upper and lower part length ratio L1 / L2 increases, the slope K shows a trend of first increasing and then decreasing. Among them, when the upper and lower part length ratio L1 / L2=3.5, that is, L1=3.5mm, L2=1mm, the slope K is the largest, and the sensor's response effect with respect to wind speed is most obvious. Therefore, the present invention selects L1 / L2=3.5, and further changes the size of the side length a to determine the optimal rigid structure size. As shown in FIG. Figure 24 As shown in (b), the present invention changes the side length a and plots a linear relationship diagram between the airflow velocity vw and the resistance response size ΔR. Figure 24 As shown in (b), the slope K gradually increases with increasing side length a. This is because as side length a increases, the force-bearing area of ​​the rigid structure increases, increasing the degree of bending of the ciliary base and, consequently, the magnitude of the resistance response. Based on the above analysis, the final rigid structure dimensions selected by the present invention are a side length a = 3 mm and a top-bottom length ratio L1 / L2 = 3.5.

[0175] Example 13: Application study of skin differentiation function

[0176] Based on the excellent detection performance of the cilia sensing unit on airflow and the touch sensing performance of the two-dimensional sensing unit, the cilia electronic skin is attached to the finger, and multi-point touch, sliding and airflow detection experiments are carried out, and the results are shown in Figure 25 . The multi-point touch and multi-point sliding are applied by the front end of the tweezers, and the touch and sliding effects are applied by following the touch point positions and sliding tracks shown in Figure 25 (a), (i), and the pressure difference can be clearly distinguished by color contrast. In 3 touch experiments, the pressure difference is large when touching, and the minimum pressure is 1130 Pa when single-point touching, and the pressure on unit No. 1 is the largest when three-point touching, about 3570 Pa. In the sliding experiment, the response result clearly presents the preset sliding track of the application, and the touch pressure generated in the sliding process is given. The pressure generated in the sliding process is relatively large, all exceeding 3000 Pa, and the pressure generated in the whole sliding process is also relatively uniform. In the process of multi-point touch and sliding touch, the application also applies airflow, and by extracting the resistance response of unit No. 4, the time-airflow velocity curve Figure 25 (e), Figure 25 (j) in

[0177] Through the experimental study of multi-point touch, sliding touch combined with airflow, the simultaneous realization of trajectory recognition, pressure recognition and airflow detection of millimeter-level cilia electronic skin in curved surface environment is also verified, and the millimeter-level electronic cilia skin has great application potential in the differentiation function of electronic skin.

[0178] Table 3 Multi-point touch pressure value of cilia electronic skin (×10 3 Pa)

[0179] Unit site b c d 1 1.20 2.54 3.57 3 - 2.14 1.13 6 - - 2.10

[0180] Table 4 Sliding sensing pressure value of cilia electronic skin (×10 3 Pa)

[0181] Unit site f g h 1 3.69 3.69 3.69 2 3.14 3.14 3.14 3 - 3.12 3.12 4 - - - 5 - 4.23 4.23 6 3.47 3.47

[0182] As can be seen from the above examples, the present invention addresses the limitations of two-dimensional sensing of electronic skin and the limited application of EGaIn in integrated electronic skin. High-performance electronic skin is prepared through a simple, efficient, and low-cost demolding method. The critical size of the electronic skin is explored, breaking through the two-dimensional limitation to obtain ciliated electronic skin. The sensor performance of the electronic skin in flat and curved environments is studied, and applications such as surface topography recognition, Braille reading, and bionic skin differentiation are realized. The specific results are as follows:

[0183] (1) The present invention prepared 3×3 mm 2 The flexible sensing unit has a good EGaIn filling effect and can accurately achieve linear sensing in the range of 10-22000Pa. It also has a high pressure resolution of 10Pa and a fast response time of 0.14s. Its excellent sensing performance makes it particularly suitable as the basic unit of electronic skin.

[0184] (2) The present invention further fabricates a three-dimensional ciliary structure on a two-dimensional sensing unit by a demolding method, and conducts multiple performance characterization comparisons on the ciliary structure dimensions, optimizing and selecting the structural dimensions with the best performance (bottom diameter D = 2 mm, ciliary length H = 3.5 mm). The ciliary sensing unit can accurately achieve linear sensing within a bending range of 15°-60°, and has a fast response time of 0.4 s. It can also accurately detect vibrations in a wide frequency range of 1-25 Hz.

[0185] (3) Using 2 mm as the critical spacing between 2×3 ciliary electronic skin sensing units can eliminate crosstalk between units. At the same time, the determination of this critical spacing also enables the ciliary electronic skin to distinguish two points 8 mm apart, which is comparable to the two-point resolution capability of human fingertips.

[0186] (4) In a flat environment, the 2×3 ciliary electronic skin can achieve precise positioning and bending angle perception for 6-point static bending touch. In a curved environment with a curvature radius ≥ 6 mm, the ciliary sensing unit can still achieve good linear response to bending angles within 15°-60°.

[0187] (5) The single-ciliary electronic skin can accurately identify and measure different surface morphologies. For tetrahedrons and hemispheres with a height of 0.5 mm and 1 mm and a spacing of 0.2 mm, the type of surface morphology can be analyzed from the curve shape. For cubes with a height of 0.5 mm and 1 mm and a spacing of 0.3 mm, the type of surface morphology can also be intuitively analyzed.

[0188] (6) The multi-ciliary electronic skin can quickly read Braille. The three ciliary sensor units can simultaneously identify and read the three columns of convex dots of Braille. The combined signal analysis of the three sensor units can quickly identify Braille.

[0189] (7) By designing multiple sets of embedded rigid structures and comparing their airflow sensing capabilities, the rigid structure size with the best performance (side length a = 3 mm, upper and lower part length ratio L1 / L2 = 3.5) was selected. The ciliary sensing unit embedded in the rigid structure has an excellent linear response to airflow velocities of 1.8 m / s-5.7 m / s.

[0190] (8) Through the experimental study of multi-touch, sliding touch and airflow, the ciliary electronic skin can realize the simultaneous detection of pressure recognition, trajectory recognition and airflow in a curved environment, and has excellent capabilities in the differentiation function of bionic electronic skin.

[0191] In summary, the present invention fabricates two-dimensional and three-dimensional ciliary electronic skins through a simple, efficient, and low-cost demolding method. The resulting ciliary electronic skins can detect airflow in addition to bending multi-touch. Single-ciliary surface topography recognition and multi-ciliary Braille recognition demonstrate their excellent three-dimensional sensing properties. By combining touch, sliding trajectory sensing, and airflow sensing, ciliary electronic skins demonstrate the function of skin differentiation. Due to their low-cost preparation and excellent sensing performance, ciliary electronic skins demonstrate significant application value and potential in bionic robots, intelligent prosthetics, and multi-dimensional detection.

[0192] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A bionic ciliary electronic skin, characterized in that: It includes a flexible substrate, a flexible circuit layer arranged on the surface of the flexible substrate, and a flexible ciliary layer arranged on the surface of the flexible circuit layer; The flexible circuit layer is provided with a two-dimensional circuit array, the two-dimensional circuit array is formed by arranging a two-dimensional circuit unit array, and the two-dimensional circuit unit is formed by a two-dimensional circuit microchannel; The flexible ciliary layer is provided with a ciliary sensing array, wherein the ciliary sensing array is formed by arranging ciliary sensing units in an array, and the ciliary sensing units are three-dimensional ciliary structures; The orthographic projection area of ​​the ciliary sensing unit on the surface of the flexible substrate at least partially overlaps with the orthographic projection area of ​​the two-dimensional circuit unit on the surface of the flexible substrate; The bionic ciliary electronic skin also includes liquid metal filled in the two-dimensional circuit microchannel.

2. The bionic ciliary electronic skin according to claim 1, characterized in that: The shape of the two-dimensional circuit unit is a square spiral pattern formed by two-dimensional circuit microchannels; the side length of the two-dimensional circuit unit is 3mm, and the circuit density is 32.0cm -1 The spacing between two adjacent two-dimensional circuit units is 1 to 2 mm; the cross-sectional shape of the two-dimensional circuit microchannel is 0.1×0.1 mm 2 square.

3. The bionic ciliary electronic skin according to claim 1, characterized in that: The three-dimensional ciliary structure is in the shape of a solid cone, and the bottom diameter of the three-dimensional ciliary structure is 0.8 to 2 mm, and the height is 2.5 to 4.5 mm.

4. The bionic ciliary electronic skin according to any one of claims 1 to 3, characterized in that: The thickness of the flexible substrate, flexible circuit layer and flexible cilia layer is 0.5 mm; The material of the flexible substrate is polydimethylsiloxane; the materials of the flexible circuit layer and the flexible cilia layer are platinum-catalyzed silicone rubber; the liquid metal is oxidized EGaIn, and the surface tension of the oxidized EGaIn is 517 mN·m -1 , the viscosity is 2.3×10 4 mPa·s.

5. The bionic ciliary electronic skin according to claim 4, characterized in that: The preparation method of the oxidized EGaIn comprises the following steps: The EGaIn, an inorganic strong base and water are mixed and oxidized to obtain oxidized EGaIn; the oxidation time is 2 to 6 hours.

6. The method for preparing the bionic ciliary electronic skin according to any one of claims 1 to 5, characterized in that: The following steps are involved: The cilia template, circuit template and blank base plate are obtained by 3D printing; Using the template method, a flexible ciliary layer, a flexible circuit layer, and an uncured flexible substrate were prepared using a ciliary template, a circuit template, and a blank substrate, respectively. The flexible cilia layer, the flexible circuit layer and the flexible substrate in an uncured state are sequentially stacked and bonded to obtain a semi-finished product; Liquid metal is injected into the two-dimensional circuit microchannel of the semi-finished product to obtain the bionic ciliary electronic skin.

7. The preparation method according to claim 6, characterized in that The raw material used in the 3D printing is a photosensitive resin; the 3D printing directly obtains an initial state ciliary template or an initial state circuit template; After obtaining the initial state cilia template, the method further includes: washing, photocuring and hydrophobicizing the initial state cilia template in sequence to obtain the cilia template; After the initial circuit template is obtained, the method further includes: washing and light-curing the initial circuit template in sequence to obtain the circuit template.

8. The preparation method according to claim 6, characterized in that The preparation of a flexible cilia layer or a flexible circuit layer by a template method includes the following steps: Mixing component A and component B of platinum-catalyzed silicone rubber and coating the mixture on the ciliary template or circuit template, and then performing demoulding after heat curing to obtain a flexible ciliary layer or a flexible circuit layer; The coating thickness is 0.5 mm; the thermal curing temperature is 45° C. and the curing time is 20 min.

9. The preparation method according to claim 6, characterized in that The preparation of a flexible substrate in an uncured state by a template method includes the following steps: The basic components of polydimethylsiloxane and a curing agent are mixed and then coated on a blank base plate, and demoulded after thermal curing to obtain a flexible substrate in an uncured state; The coating thickness is 0.5 mm, and the thermal curing temperature is 45° C. for 2.5 hours.

10. Use of the bionic ciliary electronic skin described in any one of claims 1 to 5 or the bionic ciliary electronic skin prepared by the preparation method described in any one of claims 6 to 9 in constructing bionic robots, preparing intelligent prostheses or preparing multi-dimensional detection equipment.

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