Stretchable conductive polymer composite electrode, preparation method, regeneration method and application

Abstract

The invention relates to a stretchable conductive polymer composite electrode, a preparation method and application thereof, the stretchable conductive polymer composite electrode is provided with a conductive network layer and a conductive polymer elastomer layer, and the conductive network layer and the conductive polymer elastomer layer are stacked to form a double-layer composite structure. The stretchable conductive polymer composite electrode disclosed by the invention has the beneficial effects of high conductivity, high stretchability, laser patterning and cyclic regeneration. And high conductivity can still be maintained under 100% tensile strain. According to the stretchable conductive polymer composite electrode, high-precision patterning can be achieved through the laser patterning technology, a flexible circuit with the minimum line width being 25 microns is prepared, and customized processing is achieved through digital design. The composite electrode can form a film again after solvent-assisted dissolution, so that closed-loop regeneration of an electrode material is realized.

Description

Technical Field

[0001] This invention relates to the field of flexible and stretchable electronic device technology, and in particular to a stretchable conductive polymer composite electrode, its preparation method, and its application. Background Technology

[0002] Current electronic technology is developing towards electronic skin, soft robots, flexible wearables, and human-computer interaction. Regardless of how system functions evolve, electrodes remain the fundamental components for forming conductive circuits in electronic systems. Stretchable electrodes are an indispensable key component in stretchable electronic devices, directly affecting their performance and practical application. Traditional metal electrodes are relatively hard and prone to breakage under stretching, bending, and torsion, leading to signal interruption. Stretchable electrodes, however, can achieve a certain degree of stretchability by incorporating special conductive materials (such as rubber doped with AgNWs) or designing special structures (such as wavy or serpentine structures). This characteristic enables stretchable electronic devices to operate stably for extended periods, making them more reliable in monitoring human muscle activity and tracking the deformation of robotic devices.

[0003] Maintaining the stability of signal transmission in stretchable electrodes is crucial for ensuring signal accuracy. When stretchable electronic devices undergo dynamic deformation, the electrodes must maintain stable conductivity to prevent signal drift caused by excessive resistance fluctuations. Furthermore, current technologies often rely on precious metals (such as gold and silver nanowires) or complex microstructure processes. This makes it difficult to balance structural complexity and cost control in stretchable electrodes, limiting the realization of high-precision customized patterns and the feasibility of large-scale mass production, thus restricting the expansion of their practical application value. In addition, traditional composite electrodes form permanent heterogeneous structures through covalent cross-linking or physical doping, making it difficult to separate and regenerate the components, exacerbating electronic waste pollution. How to achieve electrical stability under dynamic deformation while simultaneously considering structural requirements, economic costs, and environmental protection has become an urgent problem to be solved.

[0004] Therefore, it is essential to provide a stretchable conductive polymer composite electrode, its preparation method, and its application to address the shortcomings of existing technologies. Summary of the Invention

[0005] The first objective of this invention is to overcome the shortcomings of the prior art by providing a stretchable conductive polymer composite electrode. This stretchable conductive polymer composite electrode has the advantages of high stretchability and high conductivity.

[0006] The above-mentioned objectives of the present invention are achieved through the following technical measures: A stretchable conductive polymer composite electrode is provided, comprising a conductive network layer and a conductive polymer elastomer layer, wherein the conductive network layer and the conductive polymer elastomer layer are stacked to form a double-layer composite structure.

[0007] Preferably, the conductive network layer contains at least one of a two-dimensional conductive material or a conductive metal material.

[0008] When the conductive network layer contains a two-dimensional conductive material, the two-dimensional conductive material is at least one of graphene, carbon nanotubes, or MXene.

[0009] When the conductive network layer contains a conductive metal material, the conductive metal material is at least one of metal nanowires, metal particles, metal sheets, or liquid metal.

[0010] Preferably, the conductive polymer elastomer layer comprises a composite of a conductive polymer and an elastomer.

[0011] Preferably, the conductive polymer is at least one of polyacetylene, polypyrrole, polythiophene, polyaniline, poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, and polybenzodifurandione.

[0012] Preferably, the above-mentioned elastomer composite is at least one of polyurethane, thermoplastic polyurethane, polyimide, polyvinylidene fluoride, or polyacrylate.

[0013] Preferably, the conductive polymer is polybenzodifurandione.

[0014] A second objective of this invention is to overcome the shortcomings of existing technologies by providing a method for preparing a stretchable conductive polymer composite electrode. This method yields a stretchable conductive polymer composite electrode with advantages of high stretchability and high conductivity, and the preparation method involves precise patterning.

[0015] The above-mentioned objectives of the present invention are achieved through the following technical measures: A method for preparing a stretchable conductive polymer composite electrode is provided, comprising the following steps: A1. Obtain the peelable underlying layer; A2. Construct the conductive network layer on the peelable substrate of A1, and then prepare the conductive polymer elastomer layer on the conductive network layer to obtain the bilayer composite structure; or The conductive polymer elastomer layer is prepared on the peelable substrate of A1, and then the conductive network layer is formed on the conductive polymer elastomer layer to obtain the bilayer composite structure. A3. The double-layer composite structure obtained in A2 is patterned to obtain the stretchable conductive polymer composite electrode.

[0016] The present invention constructs the conductive network layer through transfer, deposition, or embedding processes.

[0017] The present invention prepares the conductive polymer elastomer layer by at least one of the following methods: coating, spin coating, spray coating, blade coating, screen printing, inkjet printing or chemical deposition.

[0018] This invention achieves patterning through laser cutting, mechanical trimming, or molding.

[0019] Preferably, the peelable substrate is a flexible substrate or a peelable support mold.

[0020] A third objective of this invention is to overcome the shortcomings of existing technologies by providing a method for regenerating stretchable conductive polymer composite electrodes. This regeneration method can recover stretchable conductive polymer composite electrodes, and the conductivity of the recovered composite electrodes can still maintain the required performance of over 80%.

[0021] The above-mentioned objectives of the present invention are achieved through the following technical measures: A method for regenerating a stretchable conductive polymer composite electrode is provided, comprising the following steps: B1. Dissolve the stretchable conductive polymer composite electrode as described above, or the stretchable conductive polymer composite electrode prepared by the above method, in an organic solvent to obtain a solution; wherein the organic solvent is at least one of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, or chloroform. B2. Obtain the peelable underlying layer; B3. A conductive network layer is formed on the peelable substrate of B2, and then a conductive polymer elastomer layer is prepared on the conductive network layer using the solution obtained in B1, to obtain the bilayer composite structure; or A conductive polymer elastomer layer is prepared on the peelable substrate of B2 using the solution obtained in B1; then a conductive network layer is formed on the conductive polymer elastomer layer to obtain the bilayer composite structure. B4. The double-layer composite structure obtained in B3 is patterned to obtain a regenerated stretchable conductive polymer composite electrode.

[0022] The conductivity of the regenerated stretchable conductive polymer composite electrode of the present invention is more than 80% of the conductivity of the stretchable conductive polymer composite electrode.

[0023] The fourth objective of this invention is to overcome the shortcomings of existing technologies and provide a stretchable conductive polymer composite electrode for use in flexible and stretchable electronic devices. This regeneration method can recover the stretchable conductive polymer composite electrode, and the recovered composite electrode still maintains a conductivity of over 80% of the required performance.

[0024] The above-mentioned objectives of the present invention are achieved through the following technical measures: This invention provides an application of a stretchable conductive polymer composite electrode in flexible and stretchable electronic devices. The stretchable conductive polymer composite electrode is the aforementioned stretchable conductive polymer composite electrode; or the stretchable conductive polymer composite electrode is a stretchable conductive polymer composite electrode prepared by a regeneration method of the aforementioned stretchable conductive polymer composite electrode; or the stretchable conductive polymer composite electrode is a regenerated stretchable conductive polymer composite electrode prepared by a regeneration method of the aforementioned stretchable conductive polymer composite electrode.

[0025] Preferably, the aforementioned flexible and stretchable electronic device is a flexible sensor, smart medical device, wearable device, or electronic skin.

[0026] This invention discloses a stretchable conductive polymer composite electrode, its preparation method, and its application. The stretchable conductive polymer composite electrode comprises a conductive network layer and a conductive polymer elastomer layer, which are stacked to form a double-layer composite structure. The stretchable conductive polymer composite electrode of this invention has the following advantages: high conductivity, high stretchability, laser patterning capability, and recyclability. It maintains high conductivity even under 100% tensile strain. Furthermore, the stretchable conductive polymer composite electrode of this invention can be patterned with high precision using laser patterning technology to fabricate flexible circuits with a minimum linewidth of 25 μm, and customized processing can be achieved through digital design. Moreover, by solvent-assisted dissolution of the original composite electrode followed by re-film formation, closed-loop regeneration of the electrode material is achieved. Under the same 100% stretching, the conductivity of the regenerated stretchable conductive polymer composite electrode can reach more than 80% of that of the original stretchable conductive polymer composite electrode. This composite electrode, which combines stretchability, conductivity, micron-level processing precision, and recyclability, not only provides high-performance stretchable electrode materials for flexible electronic devices and successfully solves the problem of mechanical mismatch between rigid electrodes and flexible substrates in wearable devices, thus replacing traditional rigid electrodes in stretchable electronic systems, but also solves the problems of electronic waste pollution and high manufacturing costs through a recyclable manufacturing model. This greatly reduces the cost of using stretchable multi-stimulus response sensors and is expected to be widely used in wearable devices, smart healthcare, and human-computer interaction. Attached Figure Description

[0027] The invention will be further illustrated with reference to the accompanying drawings, but the contents of the drawings do not constitute any limitation on the invention.

[0028] Figure 1 This is a schematic diagram of the structure of the stretchable conductive polymer composite electrode of the present invention.

[0029] Figure 2 This is a flowchart illustrating the preparation process of the stretchable conductive polymer composite electrode in Example 2.

[0030] Figure 3 These are scanning electron microscope (SEM) images of the stretchable conductive polymer composite electrode before and after stretching in Example 2. Figure 3 (a) is an unstretched scanning electron microscope image; Figure 3 (b) is a scanning electron microscope image with 100% stretch.

[0031] Figure 4 The graphs show the electrical properties of the electrodes under no stretching and under 100% stretching. Figure 4 (a) is the stretchable conductive polymer composite electrode of Example 2; Figure 4 (b) is the pure AgNWs stretchable conductive polymer composite electrode of Comparative Example 2.

[0032] Figure 5 This is a cyclic tensile test diagram of the stretchable conductive polymer composite electrode of Example 2.

[0033] Figure 6 These are micrographs of the stretchable conductive polymer composite electrode after cutting, as shown in Example 2. Figure 6 (a) A micrograph of the narrowest strip electrode patterned by laser; Figure 6 (b) is a photomicrograph of the laser-patterned edge.

[0034] Figure 7 This is a flowchart of the regeneration method for the stretchable conductive polymer composite electrode in Example 10.

[0035] Figure 8 These are comparative micrographs of the regenerated stretchable conductive polymer composite electrodes of Examples 10 and 11.

[0036] Figure 9 Electrical property diagram of stretchable conductive polymer composite electrode, in which Figure 9 (a) is the stretchable conductive polymer composite electrode of Example 2. Figure 9 (b) is the regenerated stretchable conductive polymer composite electrode of Example 10.

[0037] Figure 10 This is a schematic diagram illustrating the application of the stretchable conductive polymer composite electrode of the present invention in monitoring photoplethysmography using a transmission method. Figure 10 (a) is a schematic diagram of the transmission test method; Figure 10 (b) is a test signal diagram in self-powered mode; Figure 10 (c) is a test signal diagram in cutoff mode.

[0038] Figure 11 This is a schematic diagram illustrating the application of the stretchable conductive polymer composite electrode of the present invention in monitoring photoplethysmography using a reflective method. Figure 11 (a) is a schematic diagram of the reflection test method; Figure 11(b) is a test signal diagram in self-powered mode; Figure 11 (c) is a test signal diagram in cutoff mode.

[0039] Figure 12 This is a comparison chart showing the application effects of traditional electrodes and the stretchable conductive polymer composite electrode of this invention in monitoring electrocardiogram signals. Figure 12 (a) is a photograph of a traditional electrode patch; Figure 12 (b) is a photograph of the stretchable electrode patch; Figure 12 (c) is an electrocardiogram measured by a traditional electrode patch; Figure 12 (d) is an electrocardiogram measured by the stretchable electrode patch; Figure 12 (e) is a respiratory wave image measured by a conventional electrode patch; Figure 12 (f) is a respiratory wave image measured by a stretchable electrode patch.

[0040] Figure 13 This is a schematic diagram illustrating the application of traditional electrodes in monitoring electromyographic signals. Figure 13 (a) is a schematic diagram of traditional electrode patches for monitoring electromyographic signals; Figure 13 (b) is an electromyography signal obtained by conventional electrode patches.

[0041] Figure 14 This is a schematic diagram illustrating the application of the stretchable conductive polymer composite electrode of the present invention in monitoring electromyographic signals, wherein... Figure 14 (a) is a schematic diagram of a stretchable electrode patch for monitoring electromyographic signals; Figure 14 (b) is an electromyography signal obtained from the stretchable electrode patch.

[0042] Figure 15 A comparison of the application effects of traditional electrodes and stretchable conductive polymer composite electrodes in monitoring electroencephalogram (EEG) signals. Figure 15 (a) is a schematic diagram of traditional electrode monitoring of EEG signals; Figure 15 (b) A magnified view of the EEG signal measured by conventional electrodes and a comparison of the state with eyes open and closed; Figure 15 (c) is an EEG signal obtained by conventional electrodes; Figure 15 (d) is a schematic diagram of stretchable electrodes monitoring electroencephalogram (EEG) signals; Figure 15 (e) is a magnified view of the EEG signal measured by the stretchable electrode and a comparison with the open and closed eye state; Figure 15 (f) is an EEG signal obtained by stretchable electrodes.

[0043] exist Figures 1 to 15 This includes: Conductive network layer 100, conductive polymer elastomer layer 200. Detailed Implementation

[0044] The technical solution of the present invention will be further described with reference to the following embodiments. Unless otherwise specified, the experimental methods used in the embodiments of the present invention are conventional methods. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention can be purchased from conventional biochemical reagent stores or pharmaceutical companies.

[0045] Example 1 A stretchable conductive polymer composite electrode, such as Figure 1 As shown, a conductive network layer 100 and a conductive polymer elastomer layer 200 are provided, and the conductive network layer 100 and the conductive polymer elastomer layer 200 are stacked to form a double-layer composite structure.

[0046] It should be noted that the double-layer composite structure of the present invention forms a three-dimensional dynamic conductive network through the synergistic action of the conductive network layer 100 and the conductive polymer elastomer layer 200, and the resistance change rate is ≤10% under 100% tensile strain.

[0047] The conductive network layer 100 contains at least one of a two-dimensional conductive material or a conductive metal material. When the conductive network layer 100 contains a two-dimensional conductive material, the two-dimensional conductive material is at least one of graphene, carbon nanotubes, or MXene; when the conductive network layer 100 contains a conductive metal material, the conductive metal material is at least one of metal nanowires, metal particles, metal sheets, or liquid metal.

[0048] It should be noted that the metal nanowires of this invention can be silver nanowires. When the electrode undergoes tensile deformation, the dense network of silver nanowires can still maintain mutual contact and form continuous conductive pathways. This is due to the intrinsic high conductivity of silver material; even if the number of conductive pathways is limited, its resistance can remain relatively stable. Moreover, the length of the silver nanowires can be 10 μm to 100 μm, and the diameter can be 5 nm to 100 nm.

[0049] The conductive polymer elastomer layer 200 comprises a conductive polymer and an elastomer composite. The conductive polymer is at least one selected from polyacetylene, polypyrrole, polythiophene, polyaniline, a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, and polybenzodifuran dione. The elastomer composite is at least one selected from polyurethane, thermoplastic polyurethane, polyimide, polyvinylidene fluoride, or polyacrylate.

[0050] The conductive polymer elastomer layer 200 of the present invention can be a composite of a conductive polymer and an elastomer. Since the conductive polymer is an intrinsically conductive polymer with good conductivity, and the elastomer composite has high elasticity and impact resistance, the two composites can still maintain the conductive path under repeated stretching, bending or compression.

[0051] The stretchable conductive polymer composite electrode of this invention combines the advantages of a conductive network layer 100 and a conductive polymer elastomer layer 200, overcoming the limitations of single materials. It achieves both good conductivity and stretchability simultaneously, significantly reducing the rate of change of resistance while maintaining excellent stretchability. The organic-inorganic composite system, through interfacial coupling between materials, increases the dynamic connectivity of the conductive network and enhances the mechanical adaptability of the composite structure, thus achieving a dual improvement in electrical stability and mechanical flexibility.

[0052] The method for preparing the stretchable conductive polymer composite electrode of the present invention comprises the following steps: A1. Obtain the peelable underlying layer; A2. A conductive network layer 100 is formed on the peelable substrate of A1, and then a conductive polymer elastomer layer 200 is formed on the conductive network layer 100 to obtain a bilayer composite structure; or a conductive polymer elastomer layer 200 is formed on the peelable substrate of A1, and then a conductive network layer 100 is formed on the conductive polymer elastomer layer 200 to obtain a bilayer composite structure. A3. The double-layer composite structure obtained in A2 is patterned to obtain a stretchable conductive polymer composite electrode.

[0053] In this invention, a conductive network layer 100 is constructed through transfer, deposition, or embedding processes; a conductive polymer elastomer layer 200 is prepared by at least one of the following methods: coating, spin coating, spraying, blade coating, screen printing, inkjet printing, or chemical deposition; and patterning is performed by laser cutting, mechanical cutting, or molding. Furthermore, the underlying layer can be peeled off as a flexible substrate or a peelable support mold.

[0054] It should be noted that the present invention can first form a conductive network layer 100 on a peelable substrate, and then form a conductive polymer elastomer layer 200 on the conductive network layer 100, or it can form a conductive polymer elastomer layer 200 on a peelable substrate, and then form a conductive network layer 100 on the conductive polymer elastomer layer 200. Neither of these two methods affects the performance of the final stretchable conductive polymer composite electrode.

[0055] It should be noted that the peelable substrate of the present invention can specifically be polydimethylsiloxane. The peelable substrate is prepared by mixing dimethylsiloxane stock solution and curing agent at a mass ratio of 10:1, followed by vacuum degassing and curing, which can produce micron-scale fine structure soft molds or flexible substrates cut to specific sizes.

[0056] In step A3 of this invention, the double-layer composite structure is processed using a laser patterning method to obtain a stretchable conductive polymer composite electrode. This method enables fine and customized patterning at a depth of 25 μm or more, meeting the patterning requirements for stretchable electrodes in electronic skin or wearable devices. It should be noted that the specific process parameters used in the laser cutting step are conventional laser cutting processes, readily available to those skilled in the art, and will not be elaborated upon here. Furthermore, it should be noted that the stretchable conductive polymer composite electrode of this invention is not limited to laser cutting patterning; electrodes obtained through other patterning methods such as mechanical cutting or molding, as long as they meet the above performance requirements, are also suitable for this invention.

[0057] This stretchable conductive polymer composite electrode offers the following advantages: high conductivity, high stretchability, laser patterning capability, and recyclability. It maintains high conductivity even under 100% tensile strain. Furthermore, the stretchable conductive polymer composite electrode of this invention can be patterned with high precision using laser patterning technology to fabricate flexible circuits with a minimum linewidth of 25 μm, and customized processing can be achieved through digital design. Moreover, by solvent-assisted dissolution of the original composite electrode followed by re-film formation, closed-loop regeneration of the electrode material is realized. Under the same 100% stretching, the conductivity of the regenerated stretchable conductive polymer composite electrode can reach more than 80% of that of the original stretchable conductive polymer composite electrode. This composite electrode, which combines stretchability, conductivity, micron-level processing precision, and recyclability, not only provides high-performance stretchable electrode materials for flexible electronic devices and successfully solves the problem of mechanical mismatch between rigid electrodes and flexible substrates in wearable devices, thus replacing traditional rigid electrodes in stretchable electronic systems, but also solves the problems of electronic waste pollution and high manufacturing costs through a recyclable manufacturing model. This greatly reduces the cost of using stretchable multi-stimulus response sensors and is expected to be widely used in wearable devices, smart healthcare, and human-computer interaction.

[0058] Example 2 A stretchable conductive polymer composite electrode, such as Figure 1 As shown, other features are the same as in Example 1, except that: the conductive polymer elastomer layer 200 of this stretchable conductive polymer composite electrode is a mixture of polybenzodifuran diketone and thermoplastic polyurethane (abbreviated as PBFDO-TPU), and the solvent of the mixture is N,N-dimethylacetamide (abbreviated as DMAc). Polydimethylsiloxane (abbreviated as PDMS) serves as a peelable underlayer, specifically a soft mold. The conductive network layer 100 is made of silver nanowires, and the conductive polymer elastomer layer 200 is a PBFDO-TPU elastomer with a PBFDO to TPU mass ratio of 1:5-20, preferably 1:5.

[0059] It should be noted that, compared with other conductive polymers in Example 1, polybenzodifurandione has advantages such as n-type conductivity, high conductivity, and stretchability. Therefore, using polybenzodifurandione as a conductive polymer results in a stretchable conductive polymer composite electrode with superior performance.

[0060] The preparation process of this invention is as follows: Figure 2 As shown, silver nanowire solution and mixture are sequentially coated in a mold, dried and cured in layers to obtain a double-layer composite conductive film. Subsequently, the conductive film is patterned and transferred to the electrode region of the device to form an electrode.

[0061] The method for preparing the stretchable conductive polymer composite electrode of the present invention comprises the following steps: A1. Mix dimethylsiloxane stock solution and curing agent at a mass ratio of 10:1, degas under vacuum, and pour onto a silicon wafer with 32×32 mm glass sheet spacing. Cure at 110°C for 10 minutes to form a PDMS mold with a 0.6 mm deep groove. Use this PDMS mold as a peelable bottom layer. A2. Prepare a 50 mg / mL TPU-DMAc solution and add an equal volume of a 10 mg / mL PBFDO-DMAc solution. Stir for 1 hour to obtain a homogeneous mixture. Mix AgNWs ethanol stock solution with DMSO at a volume ratio of 1:5 and stir at 1000 rpm for 10 minutes until the solution exhibits a uniform ribbon-like luster. Drop 1 mL of AgNWs dispersion into the groove of a PDMS mold and dry at 70°C for 6 hours to form a conductive network. Cover with 1.5 mL of PBFDO-TPU solution and dry at 50°C under nitrogen for 12 hours. Peel off to obtain a double-layer composite conductive film. A3. The double-layer composite structure obtained in A2 is patterned to obtain a stretchable conductive polymer composite electrode, also known as PBFDO-TPU / AgNWs.

[0062] Comparative Example 1 A polybenzodifurandione-thermoplastic polyurethane electrode includes a conductive polymer elastomer layer 200 made of a polybenzodifurandione-thermoplastic polyurethane and an external wire.

[0063] The electrode raw material is a mixture of polybenzodifuran diketone and thermoplastic polyurethane, with N,N-dimethylacetamide (DMAc) as the solvent. Polydimethylsiloxane (PDMS) serves as the peelable underlayer, specifically a soft mold. The conductive network layer 100 is made of conductive silver paste.

[0064] The polybenzodifurandione-thermoplastic polyurethane electrode of this comparative example was prepared by coating a mixture into a mold, drying and curing it to obtain a conductive film. The cut conductive film was then connected to external wires with conductive silver paste for easy testing. Finally, it was encapsulated with a polyurethane film. The specific preparation method is as follows: A1. Mix dimethylsiloxane stock solution and curing agent at a mass ratio of 10:1, degas under vacuum, and pour onto a silicon wafer with 32×32 mm glass sheet spacing. Cure at 110°C for 10 minutes to form a PDMS mold with a 0.6 mm deep groove. This PDMS mold serves as a peelable bottom layer. A2. Prepare a 50 mg / mL TPU-DMAc solution (i.e., thermoplastic polyurethane dissolved in N,N-dimethylacetamide), add an equal volume of a 10 mg / mL PBFDO-DMAc solution (i.e., polybenzodifuran dione dissolved in N,N-dimethylacetamide), stir for 1 hour to obtain a homogeneous mixture, coat the mixture in a PDMS mold and dry and cure to obtain conductive film 1; Prepare a 100 mg / mL TPU-DMAc solution (i.e., thermoplastic polyurethane dissolved in N,N-dimethylacetamide), add an equal volume of a 10 mg / mL PBFDO-DMAc solution (i.e., polybenzodifuran diketone dissolved in N,N-dimethylacetamide), stir for 1 hour to obtain a homogeneous mixture, coat the mixture in a PDMS mold and dry and cure to obtain conductive film 2; Prepare a 200 mg / mL TPU-DMAc solution (i.e., thermoplastic polyurethane dissolved in N,N-dimethylacetamide), add an equal volume of a 10 mg / mL PBFDO-DMAc solution (i.e., polybenzodifuran diketone dissolved in N,N-dimethylacetamide), stir for 1 hour to obtain a homogeneous mixture, coat the mixture in a PDMS mold and dry and cure to obtain a conductive film 3; A3. Cut conductive film 1, conductive film 2 and conductive film 3 into sizes of 0.5×2 cm. Connect the wires at both ends of each with conductive silver paste, so that the effective conductive area in the middle is 0.5×1 cm. Then encapsulate them with a stretchable PU film to obtain three types of PBFDO-TPU electrodes. Among them, conductive film 1 corresponds to PBFDO-TPU electrode 1, conductive film 2 corresponds to PBFDO-TPU electrode 2, and conductive film 3 corresponds to PBFDO-TPU electrode 3.

[0065] The electrical and tensile properties of the three PBFDO-TPU electrodes were tested, and the results are shown in Table 1. Table 1. Performance data of three types of PBFDO-TPU electrodes

[0066] Table 1 shows the electrical and tensile properties of the three types of PBFDO-TPU. The electrode formulation can be dynamically adjusted according to different usage environments and different priorities for conductivity and tensile properties.

[0067] Comparative Example 2 An electrode with other features the same as in Example 2, except that: in this example, PBFDO-TPU is not covered on the surface of the AgNWs conductive network layer 100, and a single-layer silver nanowire conductive film AgNWs is directly peeled off to obtain the electrode. The composition and preparation method of the remaining structure are the same as in Example 2.

[0068] Test Example 1 The stretchable conductive polymer composite electrode of Example 2 and the pure AgNWs of Comparative Example 2 were subjected to electrical performance tests, such as... Figure 4 As shown, the stretchable conductive polymer composite electrode has an actual resistance of 0.72 Ω without stretching, and only 5.7 Ω when stretched to 100%, with a conductivity as high as 4.2 × 10⁻⁶. 4 S / m. Pure AgNWs have a low resistance of 1.6Ω when unstretched, but the resistance increases rapidly to 22.4Ω when stretched to 100%, indicating that the conductivity of pure AgNWs under high stretching is relatively poor.

[0069] Compared to the PBFDO-TPU electrode of Comparative Example 1, the PBFDO-TPU / AgNWs stretchable conductive polymer composite electrode of Example 2, benefiting from the excellent conductivity of AgNWs, exhibits a resistance reduction of over 90% compared to Comparative Example 1. This demonstrates that the PBFDO-TPU / AgNWs stretchable conductive polymer composite electrode maintains the high conductivity of AgNWs and uses a conductive elastomer to compensate for the changes in conductive pathways that occur when the AgNWs electrode is stretched, thus achieving both high conductivity and high stretchability. The PBFDO-TPU / AgNWs stretchable conductive polymer composite electrode of Example 2 utilizes the conductivity of the PBFDO-TPU electrode of Comparative Example 1 to partially compensate for the resistance changes during the stretching of the AgNWs electrode. Although the conductive pathways between the silver wires decrease when the electrode is stretched, a significant portion of the silver wires can form silver wire-PBFDO-silver wire conductive pathways, which can greatly reduce the rate of resistance change during stretching.

[0070] The surface condition of the PBFDO-TPU / AgNWs stretchable composite electrode in Example 2 under scanning electron microscopy during stretching, as shown in the figure. Figure 3As shown, when not stretched, the AgNWs stack together to form a dense conductive network. When stretched, the AgNWs are pulled and bent due to the deformation of the substrate, but the silver wires are not broken. The bent and deformed silver wires still stack together to form a conductive network, ensuring extremely high conductivity. The PBFDO-TPU / AgNWs stretchable composite electrode of Embodiment 2 of this invention does not fail under a stretching ratio greater than 100%.

[0071] The stretchable PBFDO-TPU / AgNWs composite electrode of Embodiment 2 of this invention exhibits minimal resistance change under prolonged and repeated stretching conditions, simultaneously possessing both high tensile strength and high conductivity. Figure 5 As shown, after 1000 cycles of 100% stretching, the entire conductive network tends to stabilize, with a resistance change of less than 10%.

[0072] The PBFDO-TPU / AgNWs stretchable composite electrode of Embodiment 2 of this invention can be laser-cut to achieve fine and customized patterns. The shape and size of the stretchable electrode under a polarizing microscope after cutting are shown below. Figure 6 As shown, the darker areas are the electrode portions that have been laser-cut away, while the lighter areas are the electrodes remaining after cutting. Many fine particles can be seen on the lighter electrode areas; this is due to the carbonized dust particles generated when the high-energy-density laser strikes the thin film sample, causing the struck areas to ablate and vaporize. The strip-shaped electrode left after laser cutting is only 24.1 μm wide, thus enabling fine patterning of over 25 μm, which can meet the patterning requirements of stretchable electrodes in electronic skin or wearable devices.

[0073] Example 3 A stretchable conductive polymer composite electrode is provided, with other features the same as in Example 2, except that: the conductive network layer 100 contains a two-dimensional conductive material, and the two-dimensional conductive material is graphene. The conductive polymer is polyacetylene, and the elastomer composite is polyurethane.

[0074] Example 4 A stretchable conductive polymer composite electrode is provided, with other features the same as in Example 2, except that: the conductive network layer 100 is a two-dimensional conductive material, and the two-dimensional conductive material is carbon nanotubes; the conductive polymer is polypyrrole, and the elastomer composite is polyurethane.

[0075] Example 5 A stretchable conductive polymer composite electrode is provided, with other features the same as in Example 2, except that: the conductive network layer 100 is a two-dimensional conductive material, and the two-dimensional conductive material is MXene. The conductive polymer is polythiophene, and the elastomer composite is polyurethane.

[0076] Example 6 A stretchable conductive polymer composite electrode is provided, with other features identical to those in Example 2, except that the conductive network layer 100 is a conductive metal material, and the conductive metal material is metal particles. The conductive polymer is a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, and the elastomer composite is polyacrylate.

[0077] Example 7 A stretchable conductive polymer composite electrode is provided, with other features the same as in Example 2, except that: the conductive network layer 100 is a conductive metal material, and the conductive metal material is a thin metal sheet. The conductive polymer is polyaniline, and the elastomer composite is polyvinylidene fluoride.

[0078] Example 8 A stretchable conductive polymer composite electrode is provided, with other features the same as in Example 2, except that: the conductive network layer 100 is a conductive metal material, and the conductive metal material is a liquid metal; the conductive polymer is polyaniline, and the elastomer composite is polyimide.

[0079] Example 9 A method for regenerating a stretchable conductive polymer composite electrode includes the following steps: B1. A solution is obtained by dissolving a stretchable conductive polymer composite electrode in an organic solvent; the organic solvent is at least one of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, or chloroform. B2. Obtain the peelable underlying layer; B3. A conductive network layer 100 is formed on the peelable underlayer of B2, and then a conductive polymer elastomer layer 200 is prepared on the conductive network layer 100 using the solution obtained in B1 to obtain a bilayer composite structure; or a conductive polymer elastomer layer 200 is prepared on the peelable underlayer of B2 using the solution obtained in B1; and then a conductive network layer 100 is formed on the conductive polymer elastomer layer 200 to obtain a bilayer composite structure. B4. The double-layer composite structure obtained in B3 is patterned to obtain a regenerated stretchable conductive polymer composite electrode.

[0080] It should be noted that the present invention can first form a conductive network layer 100 on a peelable substrate, and then form a conductive polymer elastomer layer 200 on the conductive network layer 100, or it can form a conductive polymer elastomer layer 200 on a peelable substrate, and then form a conductive network layer 100 on the conductive polymer elastomer layer 200. Neither of these two methods will affect the performance of the final stretchable conductive polymer composite electrode.

[0081] The regeneration method of this embodiment constructs a conductive network layer 100 through transfer, deposition, or embedding processes; prepares a conductive polymer elastomer layer 200 through at least one of the following methods: coating, spin coating, spraying, blade coating, screen printing, inkjet printing, or chemical deposition; and performs patterning processing through laser cutting, mechanical cutting, or molding. The peelable bottom layer is a flexible substrate or a peelable support mold.

[0082] The regeneration method of the stretchable conductive polymer composite electrode yields a regenerated stretchable conductive polymer composite electrode, whose conductivity can reach more than 80% of the original stretchable conductive polymer composite electrode under the same 100% stretching.

[0083] Example 10 A method for regenerating a stretchable conductive polymer composite electrode as described in Example 9, wherein the waste electrode is the residual material of the PBFDO-TPU / AgNWs composite electrode after laser cutting according to Example 2 of this invention, and DMAc is used as the dissolving solvent. The reuse process is as follows: Figures 7-9 As shown, after the waste electrode is weighed, a certain volume of DMAc is added again in a specific ratio to dissolve it. Before re-forming the film, the large-diameter particles in the solution are filtered with a nylon filter head, which can reduce many agglomerated silver nanowires in the stretchable electrode. The recycled electrode can still be stretched to 100% without breaking.

[0084] The specific preparation method in this embodiment is as follows: S1. Collect and weigh the waste electrodes remaining after laser patterning. Based on the ratio of film mass to solution volume, it is known that when the film mass is 0.077g, the corresponding solution volume is 1.5mL. Calculate the volume of DMAc required to dissolve it. S2. Place the waste electrode in a glass bottle, add the appropriate volume of DMAc solvent according to the ratio, and stir vigorously for 12 hours to dissolve the electrode material, so as to obtain a uniform solution containing AgNWs and PBFDO-TPU. S3. The unfiltered solution is re-dropped into the PDMS soft mold with the AgNWs conductive network layer 100, and after drying and curing, a new double-layer composite conductive film is formed. S4. The thin film is patterned to obtain a regenerated stretchable conductive polymer composite electrode.

[0085] Example 11 A method for regenerating a stretchable conductive polymer composite electrode, which is otherwise the same as in Example 10, except that: in S2, the large-diameter particles in the solution are filtered through a nylon filter head with a pore size of 10 μm, and then a bilayer composite structure is prepared.

[0086] This embodiment can reduce many aggregated silver nanowires in the stretchable electrode, and the recycled electrode can still be stretched to 100% without breaking.

[0087] Test Example 2 The surface morphology of the regenerated stretchable conductive polymer composite electrodes obtained by the two treatment methods in Example 10 and Example 11 was observed. The results showed that there were many agglomerated AgNWs in the unfiltered regenerated stretchable conductive polymer composite electrode, while only a small amount of AgNWs remained in the filtered regenerated stretchable conductive polymer composite electrode.

[0088] Although AgNWs have a diameter of only 50 nm, their length is generally 20 μm to 60 μm. Therefore, while the filter head can remove most of the AgNWs, a small portion will still pass through and remain in the solution. Although both treatment methods retain some silver wires in the regenerated electrode, these wires do not form a dense conductive network, thus offering limited improvement to the film's conductivity and not affecting the electrode's tensile properties. To obtain a regenerated electrode with superior performance, filtration is recommended as a unified treatment method.

[0089] Electrical performance tests were conducted on the regenerated stretchable conductive polymer composite electrode obtained in Example 11. The test results showed that, compared with Example 2, the resistance of the regenerated stretchable conductive polymer composite electrode in the unstretched state was 0.7Ω, consistent with the performance of the original stretchable conductive polymer composite electrode. When stretched to 100%, since the PBFDO-TPU layer assisting in the stretching of AgNWs was recycled, the resistance of the regenerated stretchable conductive polymer composite electrode increased to 6.6Ω compared to the original stretchable conductive polymer composite electrode, and the conductivity decreased by about 13%, but it still met the requirements for use in stretchable electronic devices.

[0090] Example 12 An application of a stretchable conductive polymer composite electrode in flexible stretchable electronic devices. The stretchable conductive polymer composite electrode is the stretchable conductive polymer composite electrode of Examples 1 to 8; or a regenerated stretchable conductive polymer composite electrode prepared by a regeneration method of the stretchable conductive polymer composite electrodes of Examples 9 to 11.

[0091] In existing technologies, PPG monitoring typically relies on rigid smart bracelets, which cannot achieve full stretchability and cannot be skin-fitting. This invention integrates a stretchable electrode into the sensing module of a PPG monitoring system, making it stretchable and adhesive. PPG monitoring can be categorized into transmissive and reflective types based on the path of light transmission; schematic diagrams of these two operating modes are shown below. Figure 10 and Figure 11 As shown, the PPG measured by the transmission type is as follows: Figure 10 As shown, in Figure 10The pulse waves of the pulse PD were measured in both self-powered mode (0 V) and cutoff mode (-3 V). Both modes clearly reflected the changes in light caused by blood flow during a pulse beat. Compared with the transmissive type, the amplitude of the pulse wave measured in the PPG was increased by about 30% due to the shorter light propagation path. Both modes clearly reflected the changes in light caused by blood flow during a pulse beat.

[0092] The stretchable composite electrode of this invention can serve as a wire connecting a sensor to measure PPG signals in the human body, and can also be used as a stretchable physiological electrode patch applied to the human body surface to detect ECG, EMG, and EEG signals. Comparative test results with traditional electrodes are as follows: Figures 12-15 As shown, its signal integrity is no different from that of images measured by traditional electrodes, and it can replace traditional physiological electrode patches for continuous and non-invasive detection of human physiological signals.

[0093] An electrocardiogram (ECG) is a common medical test that assesses cardiac function by recording the heart's electrical activity. It uses electrodes placed on the skin to capture the weak electrical signals generated by the heart during each cardiac cycle and convert them into waveform images. Figure 12 (c) is the electrocardiogram signal measured by a traditional electrode patch. Figure 12 (d) This is the electrocardiogram (ECG) signal measured by the stretchable electrode patch of the present invention. Comparing the two, it can be found that the levels of both electrodes are the same, both in terms of measured peak height and baseline noise; in fact, the peak signal intensity measured by the stretchable electrode patch is about 10% higher. Furthermore, the human respiratory wave can be separated from the baseline of the ECG signal, such as... Figure 12 (e) and (f) show that the signal strength increases when a person inhales and decreases when they exhale.

[0094] Electromyography (EMG) is a medical and research technique used to detect and analyze the electrical activity of muscles. It records the electrical signals generated by muscles during rest or contraction using electrodes placed on the skin surface or needle electrodes inserted into the muscle. Traditional patch electrodes measure EMG signals such as... Figure 13 As shown in (b), the electromyography (EMG) shows that whenever the hand clenches into a fist, the muscle groups in the arm exert force, and the EMG signal twitches are detected. The EMG signals measured using the stretchable electrode patch of this invention also detect the state of muscle group activity, such as... Figure 14 (b) It has the same effect as traditional electrode patches.

[0095] Electroencephalography (EEG) is a non-invasive technique for studying brain function by recording the electrical activity of a population of neurons in the brain. It utilizes electrodes attached to the scalp to capture the weak potential changes generated by the synchronous firing of a large number of neurons in the cerebral cortex and convert them into waveform signals that vary over time. Here, we compare the EEG signals measured by conventional electrodes with those measured by the stretchable electrodes of this invention, primarily analyzing the changes in brain potential caused by opening and closing the eyes. The results are as follows: Figure 15 As shown, the EEG signals measured by both types of electrodes show that when a person closes their eyes, the EEG potential initially rises and then rapidly declines; conversely, when a person opens their eyes, the potential initially falls and then rapidly rises. Therefore, this demonstrates that the stretchable electrode of this invention is as effective as traditional electrodes in monitoring EEG signals, clearly reflecting the activity of the human brain.

[0096] In summary, the stretchable composite electrode of this invention utilizes stretchable organic conductive material PBFDO / TPU as a matrix, constructing an AgNWs conductive network within it to achieve high tensile conductivity. Furthermore, it can be finely patterned to a precision of 25μm using laser patterning technology. Discarded electrodes can be recycled using DMAc and re-formed into films for reuse. The conductivity retention rate after reuse is higher than 80%, and its high conductivity and high stretchability allow it to still be used in stretchable electronic devices, reducing operating costs through recycling. Electrode patches made from this type of electrode can be used to monitor various weak physiological signals in the human body, replacing traditional electrodes for signal transmission and power supply in stretchable electronic systems, thus solving the problems of signal instability and poor economic efficiency under high stretching conditions in stretchable electronic systems.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A stretchable conductive polymer composite electrode, characterized in that: The structure comprises a conductive network layer and a conductive polymer elastomer layer, which are stacked to form a double-layer composite structure.

2. The stretchable conductive polymer composite electrode according to claim 1, characterized in that: The conductive network layer contains at least one of a two-dimensional conductive material or a conductive metallic material.

3. The stretchable conductive polymer composite electrode according to claim 2, characterized in that: When the conductive network layer contains a two-dimensional conductive material, the two-dimensional conductive material is at least one of graphene, carbon nanotubes, or MXene; When the conductive network layer contains a conductive metal material, the conductive metal material is at least one of metal nanowires, metal particles, metal sheets, or liquid metal.

4. The stretchable conductive polymer composite electrode according to claim 2, characterized in that: The conductive polymer elastomer layer comprises a composite of a conductive polymer and an elastomer. The conductive polymer is at least one of polyacetylene, polypyrrole, polythiophene, polyaniline, poly3,4-ethylenedioxythiophene and polystyrene sulfonic acid, and polybenzodifurandione. The elastomer composite is at least one of polyurethane, thermoplastic polyurethane, polyimide, polyvinylidene fluoride, or polyacrylate.

5. The stretchable conductive polymer composite electrode according to claim 4, characterized in that: The conductive polymer is polybenzodifurandione.

6. A method for preparing a stretchable conductive polymer composite electrode as described in any one of claims 1 to 5, characterized in that, The process is as follows: A1. Obtain the peelable underlying layer; A2. Construct the conductive network layer on the peelable substrate of A1, and then prepare the conductive polymer elastomer layer on the conductive network layer to obtain the bilayer composite structure; or The conductive polymer elastomer layer is prepared on the peelable substrate of A1, and then the conductive network layer is formed on the conductive polymer elastomer layer to obtain the bilayer composite structure. A3. The double-layer composite structure obtained in A2 is patterned to obtain the stretchable conductive polymer composite electrode.

7. The method for preparing the stretchable conductive polymer composite electrode according to claim 6, characterized in that: The conductive network layer is constructed using transfer, deposition, or embedding processes; The conductive polymer elastomer layer is prepared by at least one of the following methods: coating, spin coating, spraying, scraping, screen printing, inkjet printing, or chemical deposition. Patterning is achieved through laser cutting, mechanical trimming, or molding. The peelable bottom layer is a flexible substrate or a peelable support mold.

8. A method for regenerating a stretchable conductive polymer composite electrode, characterized in that: Includes the following steps: B1. Dissolve the stretchable conductive polymer composite electrode as described in any one of claims 1 to 5 or the stretchable conductive polymer composite electrode prepared by the preparation method of any one of claims 6 to 7 in an organic solvent to obtain a solution; wherein the organic solvent is at least one of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone or chloroform. B2. Obtain the peelable underlying layer; B3. A conductive network layer is formed on the peelable substrate of B2, and then a conductive polymer elastomer layer is prepared on the conductive network layer using the solution obtained in B1, to obtain the bilayer composite structure; or A conductive polymer elastomer layer is prepared on the peelable substrate of B2 using the solution obtained in B1; then a conductive network layer is formed on the conductive polymer elastomer layer to obtain the bilayer composite structure. B4. The double-layer composite structure obtained in B3 is patterned to obtain a regenerated stretchable conductive polymer composite electrode.

9. The method for regenerating the stretchable conductive polymer composite electrode according to claim 8, characterized in that: The conductivity of the regenerated stretchable conductive polymer composite electrode is more than 80% of the conductivity of the stretchable conductive polymer composite electrode.

10. An application of a stretchable conductive polymer composite electrode in flexible stretchable electronic devices, characterized in that: The stretchable conductive polymer composite electrode is the stretchable conductive polymer composite electrode according to any one of claims 1 to 5; or The stretchable conductive polymer composite electrode is a stretchable conductive polymer composite electrode prepared by the regeneration method of the stretchable conductive polymer composite electrode according to any one of claims 6 to 7. or The stretchable conductive polymer composite electrode is prepared by the regeneration method of the stretchable conductive polymer composite electrode according to any one of claims 8 to 9 to obtain a regenerated stretchable conductive polymer composite electrode. The flexible and stretchable electronic device is a flexible sensor, smart medical device, wearable device, or electronic skin.

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