Self-repairing organic silicon conductive adhesive and preparation method thereof

Abstract

The invention discloses a self-repairing organosilicone conductive adhesive and a preparation method thereof, and relates to the technical field of conductive materials, and the self-repairing organosilicone conductive adhesive comprises the following specific components: hydroxyl-terminated polydimethylsiloxane, a cross-linking agent, a catalyst, a conductive filler, tackifying resin and a rheology modifier. The composite material further comprises metal-phenol complex microgel, a halogenated polyether microphase regulator, a pyrrolo-indole self-repairing initiator and an additive of sulfimide functionalized graphene. The material is prepared based on the materials. According to the invention, four additives are introduced to cooperatively construct a multi-scale self-healing network of chemical crosslinking, reversible complexing, dynamic repairing and conductive bridging, so that not only is the conductivity efficiently recovered after multiple damages realized, but also the flexible adhesion, low-temperature crack resistance and high-temperature stability of the material are remarkably improved; and the excellent conduction capability can still be maintained under the conditions of multiple times of stretching, bending and aging, and wide engineering adaptability and high practical value are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive materials, and in particular to a self-repairing organic silicon conductive adhesive and a preparation method thereof. Background Art

[0002] Silicone conductive adhesives are widely used in electronic packaging, flexible circuits, sensors, photovoltaic connections, and other fields due to their excellent flexibility, electrical insulation, heat resistance, and good environmental adaptability. Conventional conductive adhesives usually achieve their conductive function by filling a silicone matrix with conductive fillers such as metal powder (such as silver powder) and carbon materials (such as carbon nanotubes and graphene) to form an electrical path network. However, in actual service, the material often faces complex working conditions such as mechanical stress, thermal expansion and contraction, and repeated deformation, which can easily lead to rupture of the conductive network, interface delamination, a sharp drop in conductivity, and irreversible failure, seriously affecting its long-term reliability and functional continuity in key application scenarios.

[0003] To improve the service life and environmental adaptability of conductive adhesives, previous studies have attempted to modify them by introducing thermoplastic elastomers, dynamic covalent bonds, and microencapsulated self-healing agents. However, these technologies have limitations. For example, while thermoplastic elastomers can improve mechanical properties, they cannot repair the conductive pathway structure. Microencapsulated self-healing materials often suffer from uncontrollable reactions, poor repeatability, and storage stability. Furthermore, existing technologies often overlook the interfacial compatibility between the conductive filler and the silicone matrix, which can easily lead to filler migration or sedimentation, exacerbating the functional degradation of the material during use. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a self-healing organic silicon conductive adhesive and a preparation method thereof to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: The present invention provides a self-repairing organic silicon conductive adhesive, comprising the following specific components: Hydroxyl-terminated polydimethylsiloxane, crosslinking agent, catalyst, conductive filler, tackifying resin, rheology modifier and volatility inhibitor; The organic silicon conductive adhesive further comprises additives, which specifically include: Metal-phenol complex microgels, halogenated polyether microphase regulators, pyrroloindole self-healing initiators, and sulfimide-functionalized graphene.

[0006] To further optimize this technical solution, the mass fractions of the specific components are as follows: 100-200 parts of hydroxyl-terminated polydimethylsiloxane; The cross-linking agent is 3-10 parts; The catalyst is 0.2-1 part; Conductive filler is 100-200 parts; Tackifying resin is 10-30 parts; Rheology modifier is 3-10 parts; The volatilization inhibitor is 1-5 parts.

[0007] To further optimize this technical solution, the specific components include: Hydroxy-terminated polydimethylsiloxane is an organic silicon matrix, and its terminal hydroxyl group -OH reacts with the cross-linking agent to form a cross-linked structure network; The crosslinking agent is methyltrimethoxysilane MTMS or vinyltriethoxysilane VTES, which undergoes a condensation crosslinking reaction with the terminal hydroxyl groups of the silicone matrix to construct a stable Si-O-Si three-dimensional network structure; The catalyst is an organic tin catalyst or a platinum catalyst; Conductive fillers include spherical silver powder, carbon nanotubes (CNTs), and reduced graphene oxide (rGO); The tackifying resin is methylphenyl silicone resin; The rheology modifier uses fumed silica for rheology modification; The volatility inhibitor is polyether modified silicone oil.

[0008] To further optimize this technical solution, the mass fractions of the additives are as follows: The metal-phenol complex microgel is 3-8 parts; Halogenated polyether microphase regulator is 2-6 parts; 0.5-2 parts of pyrroloindole self-repair initiator; The sulfimide functionalized graphene is 5-15 parts.

[0009] Further optimizing the technical solution, the metal-phenol complex microgel comprises a three-dimensional cross-linked microgel network formed by complexing a phenolic organic ligand having multiple ortho-phenolic hydroxyl structures with a trivalent metal ion, wherein the phenolic organic ligand is selected from gallic acid, protocatechuic acid or its derivatives, and the trivalent metal ion is selected from Fe 3+ 、Al 3+ or Cr 3+ The microgel has a particle size of 100-500 nanometers and has a reversible coordination effect, which is used to induce network reconstruction at the fracture interface and achieve self-repair.

[0010] To further optimize this technical solution, the halogenated polyether microphase regulator is a polyether molecule with a fluorinated or chlorinated end group, a main chain of which is a polypropylene glycol or polytetrahydrofuran chain segment with a molecular weight of 500-3000 Daltons. It has an intramolecular polarity gradient distribution structure, forming a microscale flexible lubricating phase for interfacial wetting enhancement, conductive filler dispersion stabilization and electromigration inhibition.

[0011] To further optimize the present technical solution, the pyrroloindole self-repairing initiator has a molecular main chain containing a conjugated structure of a pyrrole ring and an indole, and contains a reversible structural unit that can undergo a ring-opening reaction. Under external thermal or photostimulation, the silicon-oxygen main chain is induced to undergo dynamic covalent cross-linking or hydrogen bond reconstruction, which is used to assist in constructing a transient conduction path for electron migration.

[0012] To further optimize this technical solution, the sulfimide-functionalized graphene is a modified filler with -SO2NH2 functional groups covalently grafted on the surface of the graphene sheet structure. The graphene sheet has a diameter of 0.5 μm and a thickness of 15 layers. The -SO2NH2 functional group has polar siliphilicity and forms an interfacial reaction or hydrogen bond with the organic silicon chain segment.

[0013] A method for preparing a self-repairing organic silicon conductive adhesive is prepared based on the above-mentioned organic silicon conductive adhesive, comprising the following steps: S1. Preparing a silicone conductive adhesive matrix mixture: mixing hydroxyl-terminated polydimethylsiloxane, a crosslinking agent, and a catalyst to form a primary crosslinking reactant system to obtain a pre-crosslinking reaction mixture A; S2. Constructing a conductive network functional structure system: gradually adding conductive fillers to mixture A to construct a three-dimensional conductive path to form mixture B; S3, adding tackifying resin: adding tackifying resin to mixture B to enhance interfacial adhesion and shear stability to generate mixture C as an intermediate product; S4, adding rheology modifier and volatility inhibitor: adding rheology modifier and volatility inhibitor to mixture C in sequence, and obtaining mixture D of composite colloid system after treatment; S5. Constructing a reversible network microstructure regulation system: sequentially adding a metal-phenol complex microgel and a halogenated polyether microphase regulator to mixture D to form a mixture E of a pre-healing conductive adhesive having high flexibility and high energy dissipation capacity; S6. Introducing self-healing function and self-construction mechanism of conductive path: Slowly add pyrroloindole self-healing initiator and sulfimide functionalized graphene into mixture E to finally form silicone conductive adhesive.

[0014] To further optimize the present technical solution, in step S6, the finally formed silicone conductive adhesive is subjected to multiple performance tests, including volume resistivity test, elongation at break test, tensile strength test, self-repair efficiency test, shear adhesion strength test, thermal aging retention test, low-temperature flexibility test, rebound rate test, and self-repair times test.

[0015] Compared with the prior art, the present invention provides a self-repairing organic silicon conductive adhesive and a preparation method thereof, which has the following beneficial effects: This self-healing silicone conductive adhesive and its preparation method, by introducing four additives, synergistically construct a multi-scale self-healing network of "chemical cross-linking + reversible complexation + dynamic repair + conductive bridging", not only achieves efficient recovery of conductive performance after multiple damages, but also significantly improves the material's flexible adhesion, low-temperature crack resistance and high-temperature stability. It can still maintain excellent conductivity under multiple stretching, bending and aging conditions, has wide engineering adaptability and high practical value, and overcomes the main technical bottlenecks of existing conductive adhesives in terms of reliability, self-healing ability and interface stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the composition of a self-repairing organic silicon conductive adhesive proposed in the present invention; Figure 2 This is a schematic flow chart of a method for preparing a self-healing organic silicone conductive adhesive proposed in the present invention. DETAILED DESCRIPTION

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0019] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it constitute a separate or selective embodiment that is mutually exclusive with other embodiments.

[0021] Example 1: Reference Figure 1 , which is the first embodiment of the present invention, provides a self-repairing organic silicone conductive adhesive, including the following specific components: Hydroxy-terminated polydimethylsiloxane, crosslinker, catalyst, conductive filler, tackifying resin, rheology modifier and volatility suppressant.

[0022] The mass fractions of the specific components are as follows: 100 parts of hydroxyl-terminated polydimethylsiloxane; The cross-linking agent is 3 parts; The catalyst is 0.2 parts; The conductive filler is 100 parts; 10 parts of tackifying resin; The rheology modifier is 3 parts; The volatilization inhibitor is 1 part.

[0023] Hydroxyl-terminated polydimethylsiloxane (PDMS) is a silicone-based material with excellent flexibility, chemical inertness, and high- and low-temperature resistance. Its terminal hydroxyl groups (-OH) react with crosslinkers to form a crosslinked network while retaining elastic modulus, ensuring the conductive adhesive resists failure under deformation conditions such as stretching and bending. PDMS with varying molecular weights can be used to adjust the system's viscosity and post-curing modulus.

[0024] Methyltrimethoxysilane (MTMS) is used as a crosslinker, which undergoes a condensation crosslinking reaction with the terminal hydroxyl groups of the silicone matrix, forming a stable Si-O-Si three-dimensional network structure. Its dosage directly affects the curing speed and crosslinking density, thus affecting the mechanical properties, flexibility, and matrix integrity, which is the prerequisite for the self-healing ability of the conductive adhesive.

[0025] Organotin catalysts are used to catalyze the condensation or addition reaction between hydroxysiloxane and the crosslinker, forming a crosslinked network structure. Platinum-based catalysts can also be used. Platinum-based catalysts are particularly effective in systems containing vinyl siloxanes, but they are expensive and are generally used in conductive adhesives requiring high performance.

[0026] The conductive fillers include spherical silver powder, carbon nanotubes CNT and reduced graphene oxide rGO (the ratio of the three is 10:2:1). The rational combination of different types of conductive fillers can take into account both initial conductivity and strain-responsive self-healing conductivity.

[0027] The tackifying resin is a methylphenyl silicone resin, which is used to improve the bonding performance between the colloid and the substrate. It is particularly suitable for various substrates such as polymer plastics, metals and glass. It enhances the interfacial adhesion and improves the storage stability and shear strength of the system, especially ensuring the complete recovery of interfacial adhesion during the self-healing process.

[0028] Rheology modifiers use fumed silica to modify rheology, prevent filler sedimentation, and enhance structural viscoelasticity, giving the conductive adhesive thixotropy and excellent shear recovery properties. Silane modification can be applied to the surface to improve dispersibility and prevent precipitation and hardening.

[0029] The volatility inhibitor is a polyether-modified silicone oil that improves workability and prevents bubbles or shrinkage caused by rapid volatilization during the curing process. It also improves the system's wetting, spreading, and low-temperature operating stability.

[0030] The organic silicon conductive adhesive further comprises additives, which specifically include: Metal-phenol complex microgels, halogenated polyether microphase regulators, pyrroloindole self-healing initiators, and sulfimide-functionalized graphene.

[0031] The mass fractions of the additives are as follows: The metal-phenol complex microgel is 3 parts; 2 parts of halogenated polyether microphase regulator; 0.5 parts of pyrroloindole self-repair initiator; The amount of sulfimide functionalized graphene is 5 parts.

[0032] The metal-phenol complex microgel comprises a three-dimensional cross-linked microgel network formed by complexing a phenolic organic ligand having multiple ortho-phenolic hydroxyl structures with a trivalent metal ion, wherein the phenolic organic ligand is selected from gallic acid, and the trivalent metal ion is selected from Fe 3+ The microgel has a particle size of 100-500 nanometers and has a reversible coordination effect, which is used to induce network reconstruction at the fracture interface and achieve self-repair. The chemical composition of the metal-phenol complex microgel is expressed as [Fe(C7H6O5)3], where C7H6O5 is the molecular formula of gallic acid (3,4,5-trihydroxybenzoic acid); indicating that the additive is Fe 3+ The basic unit of the complex is formed by coordination with three gallic acid molecules. Compared to conventional inorganic fillers or thermoplastic elastomer toughening agents, this additive can form a reversible physical network without introducing reinforcing hard segments. It also combines charge transfer regulation with antibacterial properties, filling the gap in the existing conductive adhesive system in the lack of a "flexible, repairable, synergistic network." Furthermore, the microgel has a stable particle size, good dispersibility, and is not prone to sedimentation, significantly outperforming traditional hard particle reinforcing fillers.

[0033] Halogenated polyether microphase regulators are polyether molecules with fluorinated end groups, specifically [CF2CH2O] n , the end can be CF3, CH3 or hydroxyl, ether group, the molecular weight is 500-3000 Dalton, with an intramolecular polarity gradient distribution structure, forming a micro-scale flexible lubricating phase, which is used for interface wetting enhancement, conductive filler dispersion stabilization and electromigration inhibition. This regulator not only improves the dispersion stability of the conductive filler and prevents aggregation or migration, but also effectively enhances the stress release ability and fatigue resistance of the system by reducing surface tension and viscoelastic dissipation coefficient, and extends the service life of the material while maintaining conductive properties. Compared with the conventionally used aliphatic polyethers, non-ionic surfactants or low-molecular silicone oils, this additive has polarity controllability, heat resistance and low migration, and can form a stable and non-peeling lubricating layer at the interface. More importantly, it can still maintain the flexible connection of the conductive filler network after dynamic deformation, overcoming the problem that traditional regulators easily cause conductive path breakage.

[0034] The pyrroloindole self-repairing initiator has a molecular backbone containing a pyrrole ring and an indole conjugated structure, and contains a reversible structural unit that can undergo a ring-opening reaction. The representative monomer structure is C 11 H8N2 is a pyrroloindole conjugated molecule, such as 1H-pyrrolo[2,3-b]indole. It has two nitrogen atoms, a total of 11 carbon atoms, and 8 hydrogen atoms. Its molecular structure contains a conjugated π-electron system, which can induce self-repair-related reactions in the excited state. External thermal or photostimulation induces dynamic covalent crosslinking or hydrogen bond reconstruction of the silicon-oxygen backbone, which is used to assist in the construction of a transient conduction path for electron migration. Traditional self-healing systems rely on microencapsulated self-healing agents, thermoplastic polymer blocks, or reversible Diels-Alder structures, which suffer from high response temperatures, uncontrollable reactions, and poor repeatability. This additive, however, does not rely on additional packaging or high-temperature external fields and offers the advantages of low-energy triggering, high reaction selectivity, and a stable conjugated structure. It is particularly suitable for flexible, low-modulus, and highly sensitive conductive adhesive systems, and has higher integrated stability and cyclic durability.

[0035] Sulfimide-functionalized graphene is a modified filler with -SO₂NH₂ functional groups covalently grafted onto the surface of a graphene sheet structure. The graphene sheet has a diameter of 0.5 μm and a thickness of 15 layers. Each sheet has multiple functionalized sites on its surface, with an actual functional group density of 0.1-1.2 mmol / g. The -SO₂NH₂ functional groups are polar and siliphilic, forming interfacial reactions or hydrogen bonds with organosilicon segments. In a conductive adhesive system, this additive can form hydrogen bonds or weak covalent bonds with organosilicon segments or other functional molecules, improving the filler's dispersion and interfacial bonding strength within the silicon matrix. It also facilitates rapid reconnection and reconstruction after a conductive network breakage, achieving a "self-healing bridging" effect at the filler level. Traditional graphene often suffers from poor dispersion or agglomeration due to its surface inertness, affecting the continuity of the conductive path. However, this additive, due to surface functionalization treatment, has stronger interfacial activity and structural controllability. It can not only improve its stability in organic silicone, but also form an auxiliary conductive bridge when the structure breaks, effectively alleviating the conductive failure problem caused by load, deformation or stress, and significantly improving the reusability and reliability of the material.

[0036] Example 2: Reference Figure 2 , which is the second embodiment of the present invention, provides a method for preparing a self-repairing organic silicon conductive adhesive, which is prepared based on the organic silicon conductive adhesive described in Example 1, and includes the following steps: S1. Prepare the silicone conductive adhesive matrix mixture: Place a predetermined amount of hydroxyl-terminated polydimethylsiloxane into a planetary mixer and stir at a low speed (300 rpm). Slowly add the pre-mixed crosslinker dropwise while maintaining the system temperature below 35°C to prevent premature condensation. Then, add the catalyst and continue stirring for 10 minutes to fully disperse the mixture, yielding a pre-crosslinked reaction mixture A.

[0037] This step aims to build the conductive adhesive's flexible backbone and crosslinking reaction framework, ensuring good ductility, flexibility, and controllable subsequent network structure. By mixing hydroxyl-terminated polydimethylsiloxane, a crosslinker, and a catalyst, a primary crosslinking reactant system is formed, providing a reactive environment for the subsequent embedding of functional fillers.

[0038] S2. Constructing a Conductive Network Functional Structure: Gradually add conductive fillers to Mixture A while stirring and applying vacuum (-0.08 MPa) to remove any interstitial air introduced by the fillers. Use a high-shear dispersion device (1500 rpm) for 15 minutes to uniformly embed the conductive particles into the cross-linked network structure, forming Mixture B.

[0039] This step further introduces composite conductive fillers to construct three-dimensional conductive pathways, ensuring the material's high conductivity and strain responsiveness. The conductive fillers must be uniformly dispersed within the matrix to avoid agglomeration and pathway breakage.

[0040] S3. Adding Tackifying Resin: Add the pretreated tackifying resin to Mixture B. Maintain the mixing temperature at 40-50°C and stir at a low speed (500 rpm) for 10 minutes to ensure uniform distribution of the resin within the silicone network. After the tackifying resin is added, the system viscosity increases slightly, transitioning to a highly elastic shear state, producing the intermediate product, Mixture C.

[0041] This step introduces a tackifying resin into mixture B to improve the adhesion of the conductive adhesive to different substrates (such as metal, asphalt aggregate, polymer substrate, etc.), while also enhancing the initial bonding strength of the system and fatigue resistance after curing.

[0042] S4. Adding a rheology modifier and a volatility inhibitor: Add the rheology modifier and volatility inhibitor sequentially to mixture C. Stir using a vacuum homogenizer, maintaining a pressure of -0.09 MPa, for approximately 20 minutes. The rheology modifier preferentially interacts with the polar groups in the network, forming a micro-grid structure and enhancing low-shear stability. The volatility inhibitor coats the liquid phase components, reducing the volatilization rate of organic matter. This treatment yields a composite colloidal system mixture D.

[0043] This step improves the system's construction performance, thixotropic properties and low-temperature stability by introducing rheology regulators and volatility inhibitors, suppresses undesirable phenomena such as sag, sedimentation, and bubbles that occur during the coating and dispensing process of the conductive adhesive, and improves environmental stability and storage life.

[0044] S5. Constructing a reversible network microstructure regulation system: Add the metal-phenol complex microgel and the halogenated polyether microphase regulator to mixture D in sequence, maintaining a strictly controlled ratio within the recommended mass range and maintaining a stirring temperature no higher than 40°C. After addition, the mixture is treated with magnetic stirring and sonication for 10 minutes to ensure uniform distribution of the microgel and formation of a stable phase for the polyether regulator. This ultimately forms a pre-healable conductive adhesive mixture E with high flexibility and high energy dissipation capacity.

[0045] This step, by introducing a metal-phenol complex microgel and a halogenated polyether microphase modifier, creates a reversibly responsive, flexible, physically cross-linked network and lubricated microphase structure within the system, thereby enhancing its self-healing and strain recovery properties. This microstructure facilitates the reconstruction of the conductive network and load distribution after damage.

[0046] S6. Introducing self-healing function and self-construction mechanism of conductive path: Slowly add pyrroloindole self-healing initiator to mixture E and stir for 5 minutes in a dark state; then introduce sulfimide-functionalized graphene and use high-speed homogenizer to disperse it at nanoscale (3000 rpm, 10 minutes), finally forming a conductive adhesive with uniform structure, good self-healing performance and stable conductivity.

[0047] The addition of pyrroloindole self-healing initiators and sulfimide-functionalized graphene gives the material the ability of "fracture-activated structural repair" and "self-construction of electrical conduction pathways" respectively, so that the conductive adhesive can still achieve rapid closure and mechanical strength recovery after cracking or breaking due to stress during use.

[0048] The final silicone conductive adhesive was subjected to multiple performance tests, including volume resistivity test, elongation at break test, tensile strength test, self-repair efficiency test, shear adhesion strength test, heat aging retention test, low-temperature flexibility test, rebound rate test, and self-repair times test. The test contents are as follows: 1. Volume resistivity test The four-probe method was used for testing according to GB / T 1410-2006. The cured conductive adhesive was made into a 1mm thick, 10mm×10mm cube sample. The steady-state resistance was measured using the standard current injection and voltage sampling method, and the volume resistivity of the material was calculated.

[0049] 2. Elongation at break test Referencing the GB / T 528-2009 rubber material standard, tensile tests were performed on strip samples, and the maximum elongation ratio at sample break was recorded to evaluate the material's elongation limit under external force.

[0050] 3. Tensile strength test Also in accordance with GB / T 528-2009, the maximum tensile force required for the sample to break during the tensile process is measured using a universal material testing machine, reflecting the tensile bearing capacity of the material.

[0051] 4. Self-repair efficiency test (conductivity recovery rate) The samples were artificially cut and then left standing at room temperature for 24 hours before the conductivity was measured. The conductivity was compared with that of the original sample to calculate the recovery percentage of the conductivity.

[0052] 5. Shear bond strength test In accordance with GB / T 7124-2008, a shear load is applied to the bonding surface between the sample and the aluminum plate, and the maximum shear force required for failure is measured to reflect the material's adhesion to various substrates.

[0053] 6. Thermal aging retention test The samples were treated in an aging chamber at 85°C for 100 hours, and their conductivity changes were tested and compared with unaged samples to evaluate their ability to maintain thermal stability of conductivity.

[0054] 7. Low temperature flexibility test (-40℃ bending) After placing the sample in a -40°C low-temperature box at a constant temperature for 1 hour, bend it 180° continuously for 5 times to observe whether the sample has any failure phenomena such as cracking, splitting, or peeling.

[0055] 8. Rebound rate test According to GB / T 6669-2008, the sample is compressed under a fixed compressive stress, then released and its rebound height or recovery length is measured, and its elastic retention rate is calculated to reflect the structural recovery ability of the material.

[0056] 9. Self-repair times test The samples were subjected to multiple cycles of “destruction – self-repair – retesting the conductivity”, and the upper limit of the number of cycles at which the conductivity could be effectively restored without external stimulation was recorded.

[0057] The above test results are shown in Table 1.

[0058] Table 1

[0059] From the test results of the self-healing silicone conductive adhesive provided in Table 1, it can be seen that the material exhibits excellent properties in terms of conductivity, mechanical properties, environmental adaptability and self-healing ability: Excellent conductive properties: volume resistivity is only 1.2×10 -3 Ω·cm, meeting most flexible connection or shielding conductivity requirements.

[0060] Excellent mechanical properties: elongation at break is as high as 180%, and tensile strength is 1.6MPa, indicating that the material has a coordinated ratio of high flexibility and moderate strength.

[0061] Strong bonding strength: The shear bonding strength is 2.1MPa, which can achieve strong bonding with different engineering materials (such as metals, cable sheaths, and composite substrates).

[0062] High self-healing efficiency: After self-healing at room temperature, the conductivity recovery rate is as high as 92.5%, which is significantly higher than that of the traditional silicone system, verifying the effectiveness of the designed self-healing network.

[0063] Strong adaptability to thermal aging and environment: after aging at 85°C for 100 hours, it can still maintain 88.3% of the electrical conductivity, and no cracking occurs after low-temperature bending, proving that it is suitable for complex high and low temperature working conditions.

[0064] Stable rebound ability: The rebound rate reaches 78.4%, indicating that the material structure can still recover well after external compression, and is suitable for repeated dynamic load conditions.

[0065] Outstanding repeated repair ability: it can complete more than 6 complete destruction-recovery cycles, and there is no significant decrease in conductive performance between cycles, demonstrating good "cyclic self-healing ability".

[0066] In summary, the self-healing silicone conductive adhesive provided by the present invention has excellent flexibility, strong adhesion and multiple self-healing capabilities while maintaining high conductivity. It is particularly suitable for engineering scenarios such as flexible electronic devices, road sensing monitoring systems, and intelligent bonding layer materials that have high requirements for both structural integrity and electrical performance. It has broad engineering application prospects and significant technological advancement.

[0067] 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 present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A self-repairing silicone conductive adhesive, characterized in that: It includes the following specific components: Hydroxyl-terminated polydimethylsiloxane, crosslinking agent, catalyst, conductive filler, tackifying resin, rheology modifier and volatility inhibitor; The organic silicon conductive adhesive further comprises additives, which specifically include: Metal-phenol complex microgels, halogenated polyether microphase regulators, pyrroloindole self-healing initiators, and sulfimide-functionalized graphene.

2. The self-repairing organic silicon conductive adhesive according to claim 1, characterized in that: The mass fractions of the specific components are as follows: 100-200 parts of hydroxyl-terminated polydimethylsiloxane; The cross-linking agent is 3-10 parts; The catalyst is 0.2-1 part; Conductive filler is 100-200 parts; Tackifying resin is 10-30 parts; Rheology modifier is 3-10 parts; The volatilization inhibitor is 1-5 parts.

3. The self-repairing organic silicon conductive adhesive according to claim 1, characterized in that: Among the specific components: Hydroxy-terminated polydimethylsiloxane is an organic silicon matrix, and its terminal hydroxyl group -OH reacts with the cross-linking agent to form a cross-linked structure network; The crosslinking agent is methyltrimethoxysilane MTMS or vinyltriethoxysilane VTES, which undergoes a condensation crosslinking reaction with the terminal hydroxyl groups of the silicone matrix to construct a stable Si-O-Si three-dimensional network structure; The catalyst is an organic tin catalyst or a platinum catalyst; Conductive fillers include spherical silver powder, carbon nanotubes (CNTs), and reduced graphene oxide (rGO); The tackifying resin is methylphenyl silicone resin; The rheology modifier uses fumed silica for rheology modification; The volatility inhibitor is polyether modified silicone oil.

4. The self-repairing organic silicon conductive adhesive according to claim 1, characterized in that: The mass fractions of the additives are as follows: The metal-phenol complex microgel is 3-8 parts; Halogenated polyether microphase regulator is 2-6 parts; 0.5-2 parts of pyrroloindole self-repair initiator; The sulfimide functionalized graphene is 5-15 parts.

5. The self-repairing organic silicon conductive adhesive according to claim 1, characterized in that: The metal-phenol complex microgel comprises a three-dimensional cross-linked microgel network formed by complexing a phenolic organic ligand having multiple ortho-phenolic hydroxyl structures with a trivalent metal ion, wherein the phenolic organic ligand is selected from gallic acid, protocatechuic acid or its derivatives, and the trivalent metal ion is selected from Fe 3+ 、Al 3+ or Cr 3+ The microgel has a particle size of 100-500 nanometers and has a reversible coordination effect, which is used to induce network reconstruction at the fracture interface and achieve self-repair.

6. The self-repairing organic silicon conductive adhesive according to claim 1, characterized in that: The halogenated polyether microphase regulator is a polyether molecule with a fluorinated or chlorinated end group, a polypropylene glycol or polytetrahydrofuran chain segment, a molecular weight of 500-3000 Daltons, and an intramolecular polarity gradient distribution structure, forming a microscale flexible lubricating phase for enhancing interfacial wetting, stabilizing the dispersion of conductive fillers, and inhibiting electromigration.

7. The self-repairing organic silicon conductive adhesive according to claim 1, characterized in that: The pyrroloindole self-repairing initiator has a molecular main chain containing a conjugated structure of a pyrrole ring and an indole, and contains a reversible structural unit that can undergo a ring-opening reaction. Under external thermal or photostimulation, it induces dynamic covalent cross-linking or hydrogen bond reconstruction of the silicon-oxygen main chain, which is used to assist in constructing a transient conduction path for electron migration.

8. The self-repairing organic silicon conductive adhesive according to claim 1, characterized in that: The sulfimide-functionalized graphene is a modified filler with -SO2NH2 functional groups covalently grafted on the surface of the graphene sheet structure. The graphene sheet has a diameter of 0.5 μm and a thickness of 15 layers. The -SO2NH2 functional groups have polar silicidity and form interfacial reactions or hydrogen bonds with organic silicon chain segments.

9. A method for preparing a self-repairing organic silicon conductive adhesive, prepared based on the organic silicon conductive adhesive according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Preparing a silicone conductive adhesive matrix mixture: mixing hydroxyl-terminated polydimethylsiloxane, a crosslinking agent, and a catalyst to form a primary crosslinking reactant system to obtain a pre-crosslinking reaction mixture A; S2. Constructing a conductive network functional structure system: gradually adding conductive fillers to mixture A to construct a three-dimensional conductive path to form mixture B; S3, adding tackifying resin: adding tackifying resin to mixture B to enhance interfacial adhesion and shear stability to generate mixture C as an intermediate product; S4, adding rheology modifier and volatility inhibitor: adding rheology modifier and volatility inhibitor to mixture C in sequence, and obtaining mixture D of composite colloid system after treatment; S5. Constructing a reversible network microstructure regulation system: sequentially adding a metal-phenol complex microgel and a halogenated polyether microphase regulator to mixture D to form a mixture E of a pre-healing conductive adhesive having high flexibility and high energy dissipation capacity; S6. Introducing self-healing function and self-construction mechanism of conductive path: Slowly add pyrroloindole self-healing initiator and sulfimide functionalized graphene into mixture E to finally form silicone conductive adhesive.

10. The method for preparing a self-repairing organic silicon conductive adhesive according to claim 9, characterized in that: In step S6, the finally formed silicone conductive adhesive is subjected to multiple performance tests, including volume resistivity test, elongation at break test, tensile strength test, self-repair efficiency test, shear adhesion strength test, thermal aging retention test, low temperature flexibility test, rebound rate test and self-repair times test.

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