Application of high-strength conductive hydrogel as electronic skin

Abstract

The invention discloses a high-strength conductive hydrogel which is applied to electronic skin and is directly and tightly attached to the human skin and the surface of a robot. The electronic skin has excellent mechanical properties, the elastic modulus is 0.3 MPa, the tensile strength is 2.1 MPa, and the elongation at break reaches 950%. In addition, the sensor also has a tactile feedback function with a high sensitivity coefficient, the sensitivity coefficient is 9.0, and joint movement of a person and a robot can be effectively monitored. Under the condition that the strain is 10%, the hydrogel can be repeatedly used for 1600 times, and the hydrogel has good biological safety. Therefore, when the high-strength conductive hydrogel is used as the electronic skin, not only can a robot be endowed with flexibility similar to that of human skin, but also the tactile perception capability of the robot can be remarkably improved, and the sensitivity and safety of the robot in complex environments such as human-computer interaction and the like can be enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogel electronic skin, and in particular to an application of high-strength conductive hydrogel as electronic skin. Background Art

[0002] With the rapid development of artificial intelligence and automation technology, robots are increasingly used in industry, medical care, and service fields, significantly improving production efficiency and showing great potential in medical rehabilitation, housekeeping services, education, etc. However, robots currently still face many challenges when interacting with humans and complex environments, especially in tactile perception and flexible operation. Compared with humans, robots have a large gap in perception ability, which is particularly evident in precise control and delicate operation in complex environments, especially in application fields such as brain-computer interfaces, neural prostheses, clinical equipment, wearable technology, and virtual reality. At present, most robots are built based on hard materials such as metal, ceramics, and plastics. Although they have sufficient mechanical strength and durability, they are essentially different from the softness and wettability of biological tissues and cannot provide sensitive tactile feedback, thus affecting the accuracy and safety of their operations. Especially in scenarios of cooperation with humans, robots that lack flexible tactile feedback are prone to maladaptive or even dangerous operating behaviors. Human skin has unique mechanical properties and biological perception capabilities, which enables humans to flexibly respond to changes in the external environment in daily life and accurately complete various operational tasks. By imitating these characteristics, bionic skin materials can effectively improve the performance of robots in complex environments, especially in fields such as medical care and services that require fine manipulation and human-machine interaction, and have broad application prospects. Giving robots mechanical properties and tactile functions similar to human skin has become a key research direction for improving their intelligence level.

[0003] Most of the existing bionic skins are based on elastomeric materials. Elastomeric materials have good mechanical properties, especially excellent in stretchability and durability, and can mimic the mechanical properties of human skin. However, their biocompatibility is poor, their air permeability is insufficient, and long-term use can easily cause irritation or discomfort. In contrast, hydrogel, as a new type of flexible material, can fit human skin or robot surfaces more comfortably due to its high water content, softness, air permeability and good biocompatibility. Among them, conductive hydrogel has shown great potential in the field of tactile sensing because of its softness and conductivity. Its softness enables it to adapt to mechanical stress or deformation and fit well with complex surfaces; by introducing conductive components such as metal particles, conductive polymers or conductive nanoparticles, hydrogels can sense strain or stress through changes in resistance and convert mechanical signals into electrical signals.

[0004] However, the mechanical properties of hydrogels are far inferior to those of elastomers, and they are difficult to withstand large mechanical stresses in complex operating environments, which has become a major bottleneck in their application in bionic skin. Therefore, how to design and prepare high-strength conductive hydrogels with good mechanical properties and sensitive sensing performance has become a key issue in realizing highly sensitive tactile feedback electronic skin. Summary of the invention

[0005] The purpose of the present invention is to solve the above technical problems and provide a high-strength conductive hydrogel for use as electronic skin. While retaining the softness, air permeability and good biocompatibility of the hydrogel, the material significantly improves its mechanical properties, can form a good fit with human skin or robot surface, and has both flexibility and strength, suitable for application requirements in complex environments. At the same time, the material exhibits excellent stress-strain sensing sensitivity, can accurately detect small deformation changes during the process of grasping objects, and effectively identify different objects, therefore, it can be applied as high-performance tactile sensing electronic skin.

[0006] The technical solution adopted by the present invention is: an application of a high-strength conductive hydrogel as electronic skin, the hydrogel can fit tightly with human skin or the surface of a robot and has a tactile feedback function.

[0007] Preferably, the high-strength conductive hydrogel is directly attached to human skin or the surface of a robot to monitor the movement of the human body or the robot, including the grasping, picking up and transporting actions of the robot fingers; identifying objects of different sizes; and being able to be reused 1,600 times under a strain of 10%.

[0008] Preferably, the elastic modulus of the hydrogel is 0.3 MPa, the tensile strength is 2.1 MPa, and the elongation at break is 950%.

[0009] Preferably, the sensitivity coefficient of the hydrogel is in the range of 3.4-9.0.

[0010] Further preferably, the method for preparing the high-strength conductive hydrogel comprises the following steps:

[0011] S1. Irgacure 819 (0.02 mol %, relative to methyl acrylate), 1,6-hexanediol dimethacrylate (0.36 mol %, relative to methyl acrylate) and methyl acrylate were uniformly mixed to obtain a solution A;

[0012] S2, vortexing and mixing 1 g of acrylamide, a conductive component (0.15-1.5 mg / ml, relative to water) and 2 ml of an aqueous solution containing 1% v / v Tween 80 to obtain a solution B;

[0013] S3. Mix solution A and solution B evenly in a volume ratio of 1:3, inject into a mold, initiate polymerization, and obtain a high-strength conductive hydrogel.

[0014] More preferably, the conductive component is one of PEDOT:PSS, carbon black, graphene, carbon nanotubes or inorganic salts.

[0015] More preferably, the mold is a three-dimensional cavity mold corresponding to the surface of the moving part of the human body or robot that needs to be monitored, including finger molds or toe molds corresponding to fingers or toes, and hand molds or foot molds corresponding to palms or soles.

[0016] The beneficial effects of the present invention are:

[0017] 1. The present invention prepares a high-strength conductive hydrogel and applies it as an electronic skin that fits tightly on the surface of a mechanical finger. The electronic skin has excellent mechanical properties, with an elastic modulus of 0.3MPa, a tensile strength of 2.1MPa, and an elongation at break of up to 950%. At the same time, its sensitivity coefficient is as high as 9.0.

[0018] 2. The hydrogel electronic skin in the present invention can fit tightly with the mechanical surface or human skin and has excellent tactile feedback function. It can identify the grasping action of the mechanical finger and monitor the grasping, picking and transportation process; identify objects of different sizes; and under the condition of 10% strain, it can be reused up to 1,600 times.

[0019] 3. The preparation method of the hydrogel electronic skin in the present invention is simple and easy to operate, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The effect pictures before and after the robot hand wears the hydrogel electronic skin prepared in Implementation 1, the left picture is before wearing, and the right picture is after wearing.

[0021] Figure 2 This is the stress-strain diagram of the hydrogel electronic skin in Example 2.

[0022] Figure 3 The resistance change rate of different PEDOT:PSS (0.15 mg / mL and 1.5 mg / ml, relative to water) in Example 3.

[0023] Figure 4 This is the sensitivity coefficient measurement of the hydrogel skin in Example 3.

[0024] Figure 5 For Example 4, the hydrogel electronic skin was stretched to 10% strain for 1600 cycles with continuous monitoring and characterization of its performance.

[0025] Figure 6This is a diagram of electrical signals of Example 5 in which the electronic skin monitors the changes in a person's finger from straightening (0°) to bending 90° and its multiple repetitions.

[0026] Figure 7 This is a diagram of electrical signals during the bending process of the robot joints monitored by the bionic electronic skin in Example 6.

[0027] Figure 8 This is a diagram of electrical signals of the bionic electronic skin of Example 7 monitoring the process of grabbing, carrying and putting down a heavy object.

[0028] Fig. 9 This is the bionic electronic skin of Example 8 that recognizes objects of different sizes. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0030] Example 1

[0031] The hydrogel for electronic skin was prepared by the following steps.

[0032] (1) 10 mg of Irgacure 819, 100 μL of 1,6-hexanediol dimethacrylate and 10 ml of oil-soluble monomer methyl acrylate were mixed to obtain solution A;

[0033] (2) 10 g of acrylamide and PEDOT:PSS (0.15 mg / mL relative to water), 200 μL of Tween80, and 20 mL of deionized water were shaken and mixed to obtain solution B;

[0034] (3) Solutions A and B are mixed together, stirred with a magnet for 5 minutes, and then injected into a finger mold. The hydrogel electronic skin is then obtained by irradiating with 10 W white light for more than 5 minutes.

[0035] Example 2

[0036] The hydrogel for electronic skin was prepared by the following steps.

[0037] (1) 10 mg of Irgacure 819, 100 μL of 1,6-hexanediol dimethacrylate and 10 ml of oil-soluble monomer methyl acrylate were mixed to obtain solution A;

[0038] (2) 10 g acrylamide and PEDOT:PSS (1.5 mg / ml, relative to water), 200 μL Tween80, and 20 mL deionized water were shaken and mixed to obtain solution B;

[0039] (3) Solutions A and B are mixed together, stirred with a magnet for 5 minutes, and then injected into a finger mold. The hydrogel electronic skin is then obtained by irradiating with 10 W white light for more than 5 minutes.

[0040] Example 3

[0041] The mechanical properties of the hydrogel electronic skin prepared in Example 1 and Example 2 were tested using a universal tensile machine (HZ-1004 desktop computer servo material testing machine), and their sensitivity coefficients were detected.

[0042] When the content of the conductive component PEDOT:PSS is 0.15mg / mL, the tensile strength of the electronic skin is 2.1MPa, the elongation at break is 9.5, and the sensitivity coefficient is 3.4-6.9; when the content of PEDOT:PSS is 1.5mg / mL, the tensile strength of the electronic skin is 1.4MPa, the elongation at break is 8.2, and the sensitivity coefficient is 3.6-9.0. The two embodiments have their own advantages in mechanical properties and sensor sensitivity.

[0043] Example 4

[0044] A universal tensile machine (HZ-1004 desktop computer servo material testing machine) was used to perform a small strain cycle test on the hydrogel electronic skin prepared in Example 1, and the test condition was a strain of 10%.

[0045] Example 5

[0046] The electronic skin prepared in Example 1 was fixed on human skin using medical polyurethane tape, and the electronic skin was connected to a digital source meter to monitor in real time the change in resistance signal during 26 cycles of a human finger continuously and dynamically moving from straightening (0°) to bending (90°) and then straightening.

[0047] Example 6

[0048] like Figure 1 As shown, the electronic skin finger mold prepared in Example 1 is put on a robotic hand, and the electronic skin is connected to a digital source meter. It is bent at different angles (0°, 45°, 90°) and maintained at the angle. The digital source meter is used to monitor in real time the change of the electronic skin's resistance signal as the bending angle of the robotic finger changes.

[0049] Example 7

[0050] like Figure 1 As shown, the electronic skin fingerprint prepared in Example 1 is put on a robot, and the electronic skin is connected to a digital source meter. The robot is used to perform dynamic movements of continuously grabbing, moving and putting down heavy objects, and the digital source meter is used to monitor in real time the changes in the resistance signal of the electronic skin as the robot moves dynamically.

[0051] Example 8

[0052] like Figure 1 As shown, the electronic skin finger mold prepared in Example 1 is put on a robot, and the electronic skin is connected to a digital source meter to grab objects of different sizes. The digital source meter is used to monitor in real time the change of the electronic skin's resistance signal as the robot grabs the object.

[0053] The specification and drawings of the present invention are considered to be illustrative rather than restrictive. On the basis of the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features according to the disclosed technical content without creative labor, all of which are within the protection scope of the present invention.

Claims

1. Application of a high-strength conductive hydrogel as electronic skin, characterized in that: The high-strength conductive hydrogel can fit tightly with human skin or the surface of a robot and has a tactile feedback function.

2. The use according to claim 1, characterized in that: The high-strength conductive hydrogel is directly bonded to human skin or the surface of a robot to monitor human or robot movements, including the grasping, picking up and transporting actions of the robot fingers; identifying objects of different sizes; and can be reused 1,600 times under a strain of 10%.

3. The use according to claim 1, characterized in that: The elastic modulus of the hydrogel is 0.3 MPa, the tensile strength is 2.1 MPa, and the elongation at break is 950%.

4. The use according to claim 1, characterized in that: The sensitivity coefficient of the hydrogel ranges from 3.4 to 9.

0.

5. The use according to claim 1, characterized in that: The method for preparing the high-strength conductive hydrogel comprises the following steps: S1. Irgacure 819 (0.02 mol %, relative to methyl acrylate), 1,6-hexanediol dimethacrylate (0.36 mol %, relative to methyl acrylate) and methyl acrylate were uniformly mixed to obtain a solution A; S2, vortexing and mixing 1 g of acrylamide, a conductive component (0.15-1.5 mg / ml, relative to water) and 2 ml of an aqueous solution containing 1% v / v Tween 80 to obtain a solution B; S3. Mix solution A and solution B evenly in a volume ratio of 1:3, inject into a mold, initiate polymerization, and obtain a high-strength conductive hydrogel.

6. The use according to claim 5, characterized in that: The conductive component is one of PEDOT:PSS, carbon black, graphene, carbon nanotubes and inorganic salts.

7. The use according to claim 5, characterized in that: The mold is a three-dimensional cavity mold corresponding to the surface of the moving part of the human body or robot that needs to be monitored, including a finger mold or a toe mold corresponding to a finger or a toe, and a hand mold or a foot mold corresponding to a palm or a sole.

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