A non-irritating self-conductive liquid metal composite material and preparation and application thereof

Abstract

The present application relates to a kind of non-irritating self-conducting liquid metal composite material and its preparation and application, according to mass percentage, the component of the liquid metal composite material includes dynamic crosslinking polymer 30-70%, liquid metal 30-70%.The liquid metal composite material of the present application has the self-conducting characteristics of no additional stimulation, better bonding and recyclable performance, and has good resistance to a variety of environments, breaks through many limitations in the preparation and use of traditional liquid metal composite material, has extremely high technical value and industrialization application prospect.

Description

Technical Field

[0001] This invention belongs to the field of conductive materials, and specifically relates to a non-irritating, self-conductive liquid metal composite material and its preparation and application. Background Technology

[0002] Liquid metals, with their unique physicochemical properties—combining the functionality of metals with the deformability of fluids—show significant development potential in the field of smart materials. Compared to traditional rigid components, liquid metals are more conducive to the research and development of flexible devices, sensing and conductive systems, and can greatly advance the development of related fields.

[0003] Despite this, liquid metals are generally not used alone as materials, but rather combined with various matrix materials to form composites. Traditional composite processes typically involve adding liquid metals to incompletely cured polymer systems. To form a complete conductive pathway, a large amount of liquid metal (>70%) is usually required for composite formation. However, issues such as large-scale composite formation and poor compatibility between liquid metals and matrix materials can easily lead to leakage during use. Furthermore, the surface of liquid metals is prone to oxidation and becomes non-conductive; therefore, most liquid metal composites require an additional sintering process to form a conductive pathway. In addition, the composite and usage processes place higher demands on the matrix materials: to facilitate composite formation with liquid metals, the matrix materials need to have good processability, remain stable during use, and allow for molecular-level disassembly and recycling of the matrix and liquid metal after use. However, most current composite materials use thermoplastic matrix materials, which have poor tolerance to complex environments, resulting in a significant decrease in the conductivity of the composite material during use; some matrix materials are thermosetting materials, lacking reprocessing and recycling capabilities; and some matrix materials are novel dynamic polymers, but these are usually single-layer dynamic polymers, making recycling complex and resulting in low separation rates. Furthermore, many flexible liquid metal composite materials lack intrinsic adhesion, requiring additional adhesives for use in flexible devices, thus complicating the manufacturing process. These bottlenecks severely hinder the industrial adoption of liquid metal composite materials and urgently require effective design solutions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the technical problem to be solved by this invention is to provide a non-irritating, self-conductive liquid metal composite material and its preparation and application. This invention overcomes the technical defects of existing liquid metal composite materials, such as the need for additional stimulation and / or sintering processes to form conductive pathways and poor adhesion. The liquid metal composite material of this invention is a non-irritating, self-conductive, adhesive, and recyclable liquid metal composite material.

[0005] This invention provides a non-irritating, self-conductive liquid metal composite material, wherein, by mass percentage, the liquid metal composite material comprises 30-70% of a dual dynamic crosslinked polymer and 30-70% of liquid metal; wherein the liquid metal comprises a gallium-based liquid alloy.

[0006] The structural formula of the dual dynamic crosslinked polymer is as follows:

[0007]

[0008] Where R represents a polyisocyanate residue; R1 represents a polyol residue; R2 represents a curing agent residue; and m = 2-600, n = 2-600.

[0009] Polyisocyanate residues are the remaining groups of polyisocyanates other than isocyanate groups; polyol residues are the remaining groups of polyols other than hydroxyl groups; curing agent residues are the remaining groups other than maleimide groups.

[0010] The polyisocyanate includes one or more of aromatic polyisocyanates and aliphatic polyisocyanates; the polyol includes one or more of polyether polyols and polyester polyols; and the curing agent includes one or more of N,N'-(4,4'-methylenediphenyl)bismaleimide and m-phenylenebismaleimide.

[0011] Preferably, the gallium-based liquid alloy is one or more of gallium-indium alloy, gallium-indium-tin alloy, and gallium-indium-tin-zinc alloy.

[0012] The dual dynamic crosslinked polymer is prepared from raw materials containing polyisocyanate, polyol, dynamic chain extender and curing agent, wherein the dynamic chain extender is dimethylglyoxime and furfurylamine.

[0013] Preferably, the polyisocyanate includes one or more of aromatic polyisocyanates and aliphatic polyisocyanates.

[0014] More preferably, the polyisocyanate includes one or more of the following: 4,4'-methylenebis(phenyl isocyanate), toluene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane-diisocyanate, naphthalene diisocyanate, terephthalene diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-isophthalene diisocyanate, norbornene diisocyanate, dimethylbiphenyl diisocyanate, methylcyclohexyl diisocyanate, polymethylene polyphenyl isocyanate, 1,6-hexane diisocyanate, modified diisocyanates (such as liquefied MDI from Yantai Wanhua), 1,5-pentane diisocyanate, and 2,5-furan diisocyanate.

[0015] Preferably, the polyol includes one or more of polyether polyols and polyester polyols.

[0016] Preferably, the polyether polyol is selected from at least one of polypropylene glycol, polypropylene triol, polypropylene-ethylene glycol, polypropylene-ethylene triol, polytetrahydrofuran glycol, and polytetrahydrofuran triol; the polyester polyol is selected from at least one of polyethylene adipate diol, polybutylene adipate diol, polyhexane adipate diol, polycarbonate diol, polyphthalate diol, polypentyl adipate diol, polycaprolactone diol, polyethylene adipate-propylene glycol diol, polyethylene adipate-diethylene glycol diol, and polyethylene adipate-diethylene glycol diol; the molecular weight of the polyol is 400-4000.

[0017] Preferably, the curing agent includes one or more of N,N'-(4,4'-methylenediphenyl)bismaleimide and m-phenylenebismaleimide.

[0018] More preferably, the curing agent is N,N'-(4,4'-methylenediphenyl)bismaleimide.

[0019] Preferably, the molar ratio of the polyisocyanate, polyol, dimethylglyoxime, furfuralamine, and curing agent is 1.08-3.63:0.5-1.5:0.2-1.0:0.5-1.5:0.25-0.75.

[0020] Furthermore, the preparation of the dual dynamic crosslinked polymer includes: dispersing dimethylglyoxime in a polyol at 50-80℃, adding polyisocyanate and reacting for 1-3 hours, then adding furfurylamine and continuing the reaction for 0.5-1 hours, raising the temperature to 100-120℃ and continuing the reaction for 10-12 hours, then adding a curing agent and continuing the reaction at 50-80℃ for 12-36 hours to obtain the dual dynamic crosslinked polymer.

[0021] This invention provides a method for preparing a non-irritating, self-conductive liquid metal composite material, comprising:

[0022] The dual dynamic crosslinked polymer was dissolved in a solvent, then liquid metal was added, mixed well, and the solvent was removed to obtain a non-irritating, self-conductive liquid metal composite material.

[0023] Preferably, the solvent includes one or more of acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, ethyl acetate, butyl acetate, ethylene glycol ethyl ether acetate, dichloromethane, and chloroform.

[0024] More preferably, the solvent is one or more of N,N'-dimethylformamide, N,N'-dimethylacetamide, and chloroform.

[0025] Preferably, the dual dynamic crosslinked polymer is dissolved in a solvent, wherein the dissolution is ultrasonic dissolution.

[0026] The ultrasonic dissolution time is 30-70 minutes.

[0027] Furthermore, dissolving the dual dynamic crosslinked polymer in a solvent involves heating the dual dynamic crosslinked polymer at 120-160℃ for 5-10 minutes to temporarily open the crosslinked network, then cooling it before adding a solvent and ultrasonically dissolving it into a transparent solution.

[0028] Preferably, the mixing is ultrasonic mixing, and the ultrasonic time is 30-70 minutes.

[0029] Preferably, the solvent removal temperature is 50-80℃, and the time is 3-24h.

[0030] This invention provides a method for recycling a non-irritating, self-conductive liquid metal composite material, comprising:

[0031] The non-irritating, self-conductive liquid metal composite material was mixed with a solvent, heated, centrifuged, and recovered to obtain a dual dynamic cross-linked polymer and liquid metal.

[0032] Furthermore, the heating is performed at 120-160°C for 5-40 minutes.

[0033] The liquid metal composite material and solvent were mixed and heated to obtain a mixture of dual dynamic crosslinked polymer and liquid metal. The mixture was then centrifuged and the dual dynamic crosslinked polymer and liquid metal were recovered.

[0034] This invention provides an application of the non-irritating, self-conductive liquid metal composite material in the fields of flexible wearables, sensors, conductive patches, micro-devices, and electronic device repair.

[0035] Beneficial effects

[0036] This invention relates to a non-irritating, self-conductive, adhesive, and recyclable liquid metal composite material, which is composed of a dual dynamic cross-linked polymer and liquid metal. Only 30% liquid metal is required to complete the composite and achieve sinter-free self-conductivity.

[0037] Compared to a single-dynamic structure, the dual-dynamic crosslinking structure of this invention can better integrate with liquid metal, thereby promoting the formation of a liquid metal permeation network and resulting in superior conductivity. Furthermore, the asymmetric structure allows the liquid metal to be tightly packed on the polymer surface, achieving self-conductivity at low concentrations during the post-curing process of the dual-dynamic crosslinked polyurethane material. This eliminates the need for additional sintering methods such as mechanical stretching / compression to reconnect the liquid metal and restore its conductivity. The dual-dynamic crosslinked polymer interacts with the liquid metal surface through coupling, making leakage of the liquid metal less likely. The liquid metal composite material of this invention exhibits good resistance to various environments. Upon stimulation, the matrix transforms into thermoplasticity, allowing the liquid metal composite material to directly adhere to various material surfaces. Moreover, the dual-dynamic crosslinked polymer and liquid metal can be separated through thermal dissolution, enabling recycling and reuse. Attached Figure Description

[0038] Figure 1 This refers to the preparation process of liquid metal composite materials;

[0039] Figure 2 The diagram illustrates the liquid metal composite materials of Comparative Example 1 and Examples 1-5.

[0040] Figure 3 The distribution of liquid metal in single / double dynamic crosslinked polymers;

[0041] Figure 4 Optical micrographs and SEM images of the cross-sections of the liquid metal composite materials of Comparative Example 1 and Examples 1-2;

[0042] Figure 5 Planar optical micrographs of the liquid metal composite materials of Comparative Example 1 and Examples 1-2;

[0043] Figure 6 The electrical conductivity of the liquid metal composite materials in Comparative Example 1 and Examples 1-2;

[0044] Figure 7 Interaction diagrams for XPS characterization of the liquid metal composite material in Example 2;

[0045] Figure 8 To demonstrate the stable electrical conductivity of the liquid metal composite material in Example 2 in different environments;

[0046] Figure 9 The 180° peel force of the liquid metal composite material in Example 2 on various substrates;

[0047] Figure 10 This describes the recycling process of the liquid metal composite material in Example 2. Detailed Implementation

[0048] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0049] I. Source of Raw Materials

[0050] Polybutylene adipate diol was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; dimethylglyoxime (butanedione oxime), chloroform, and glycerol were purchased from Sinopharm Chemical Reagent Co., Ltd.; furfurylamine and N,N'-(4,4'-methylenediphenyl)bismaleimide were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; 4,4'-methylenebis(phenyl isocyanate) was purchased from Wanhua Chemical Group Co., Ltd.; and liquid metal was purchased from Dongguan Dingguan Metal Technology Co., Ltd.

[0051] Synthesis of dual dynamic crosslinked polymer: Dimethylglyoxime was dispersed in polybutylene adipate diol at 50 °C, and then 4,4'-methylenebis(phenyl isocyanate) was added and reacted for 3 h. Then, furfurylamine was added and the reaction continued for 0.5 h. The temperature was raised to 100 °C and the reaction continued for 12 h. Then, N,N'-(4,4'-methylenediphenyl)bismaleimide was added and the reaction was carried out at 50 °C for 27 h to obtain the dual dynamic crosslinked polymer ODAPU.

[0052]

[0053] Wherein, R represents the structural part of 4,4'-methylenebis(phenyl isocyanate) other than the isocyanate group, m ranges from 2 to 600, n ranges from 2 to 600, and m: n = 0.4-1.1: 1.

[0054] Synthesis of a single dynamic crosslinked polymer: Dimethylglyoxime was dispersed in polybutylene adipate diol at 50 °C, and then 4,4'-methylenebis(phenyl isocyanate) was added and reacted for 3.5 h. The temperature was raised to 100 °C and the reaction was continued for 12 h. Glycerol was then added and the reaction was carried out at 50 °C for 27 h to obtain the single dynamic crosslinked polymer OPU.

[0055]

[0056] Where R represents structural parts other than isocyanate groups, m ranges from 2 to 600, n ranges from 2 to 600, and m: n = 0.4-1.1: 1.

[0057] II. Related Tests

[0058] Characterization of the mechanical properties of the composite material: In the following examples, the mechanical properties of the composite material were characterized by a universal testing machine. A rectangular strip (length × width = 30 × 5 mm) was cut from the prepared sample, and the mechanical properties of the material were tested at room temperature. The uniaxial tensile rate was set to 50 mm / min.

[0059] The contact resistance of the composite material was measured directly using a digital multimeter. The conductivity was calculated by first measuring the resistivity ρ with a handheld four-probe meter, and then calculating the conductivity σ using the formula σ = 1 / ρ.

[0060] The cross-sectional morphology of the composite material was analyzed using cold field emission scanning electron microscopy. Optical microscopy characterization was performed using a super depth-of-field microscope.

[0061] X-ray photoelectron spectroscopy (XPS) was used to analyze the surface elemental chemical states of the prepared composite material. The sample was fixed on the sample stage and placed under a vacuum of better than 5 × 10⁻⁶. -8 In the mbar analysis chamber, a full-spectrum scan was first performed to determine the surface elements, followed by a high-resolution scan of the C 1s and N 1s peaks. Analytical software was then used to perform peak fitting on the C 1s and N 1s spectra to determine the carbon and nitrogen species in different chemical bonding states and their relative abundance.

[0062] Adhesion strength was evaluated using a 180° peel test. The composite material (length × width = 100 × 20 mm) was heat-treated and then bonded to different insulating substrate surfaces (100 × 2 × 2 mm). The assembled samples were placed under static load for 24 hours. Subsequently, a universal material test was performed at 5 mm / s. -1 The peel strength was measured by tearing the flexible composite material at 180° from the surface of a rigid substrate.

[0063] Example 1

[0064] 2.4 g of the dual dynamic crosslinked polymer was heated at 140 °C for 8 min, cooled, and ultrasonically dissolved in 20 ml of chloroform. Then, 0.6 g of liquid metal (gallium-indium alloy, Ga to In mass ratio of 75.5:24.5) was added, and ultrasonication continued for 30 min to ensure complete dispersion of the liquid metal in the polymer solution. The mixed solution was then poured into a tetrafluoroethylene mold and placed in an oven at 60 °C for 12 h to volatilize, yielding a liquid metal composite material, denoted as ODAPU-LM20%. Figure 1 As shown.

[0065] Example 2

[0066] 2.1 g of the dual dynamic crosslinked polymer was heated at 140 °C for 8 min, cooled, and ultrasonically dissolved in 20 ml of chloroform. Then, 0.9 g of liquid metal (gallium-indium alloy, Ga to In mass ratio of 75.5:24.5) was added, and ultrasonication was continued for 30 min to completely disperse the liquid metal in the polymer solution. The mixed solution was then poured into a tetrafluoroethylene mold and placed in an oven at 60 °C for 12 h to evaporate, yielding the liquid metal composite material, denoted as ODAPU-LM30%. Figure 1 As shown.

[0067] Example 3

[0068] 1.5g of a dual dynamic crosslinked polymer was heated at 140℃ for 8 minutes, cooled, and ultrasonically dissolved in 20ml of chloroform. Then, 1.5g of liquid metal (gallium-indium alloy, Ga to In mass ratio of 75.5:24.5) was added, and ultrasonication continued for 30 minutes to completely disperse the liquid metal in the polymer solution. The mixed solution was then poured into a tetrafluoroethylene mold and placed in an oven at 60℃ for 12 hours to evaporate, yielding a liquid metal composite material, denoted as ODAPU-LM50%. Figure 1 As shown.

[0069] Example 4

[0070] 0.9 g of the dual dynamic crosslinked polymer was heated at 140 °C for 8 min, cooled, and ultrasonically dissolved in 16 ml of chloroform. Then, 2.1 g of liquid metal (gallium-indium alloy, Ga to In mass ratio of 75.5:24.5) was added, and ultrasonication continued for 30 min to completely disperse the liquid metal in the polymer solution. The mixed solution was then poured into a tetrafluoroethylene mold and placed in an oven at 60 °C for 12 h to evaporate, yielding the liquid metal composite material, denoted as ODAPU-LM70%. Figure 1 As shown.

[0071] Example 5

[0072] 0.3 g of the dual dynamic crosslinked polymer was heated at 140 °C for 8 min, cooled, and ultrasonically dissolved in 16 ml of chloroform. Then, 2.7 g of liquid metal (gallium-indium alloy, Ga to In mass ratio of 75.5:24.5) was added, and ultrasonication was continued for 30 min to completely disperse the liquid metal in the polymer solution. The mixed solution was then poured into a tetrafluoroethylene mold and placed in an oven at 60 °C for 12 h to evaporate, yielding the liquid metal composite material, denoted as ODAPU-LM90%. Figure 1 As shown.

[0073] Comparative Example 1

[0074] 2.7 g of the dual dynamic crosslinked polymer was heated at 140 °C for 8 min, cooled, and ultrasonically dissolved in 24 ml of chloroform. Then, 0.3 g of liquid metal (gallium-indium alloy, Ga to In mass ratio of 75.5:24.5) was added, and ultrasonication was continued for 30 min to completely disperse the liquid metal in the polymer solution. The mixed solution was then poured into a tetrafluoroethylene mold and placed in an oven at 60 °C for 12 h to volatilize, yielding a liquid metal composite material, denoted as ODAPU-LM10%. Figure 1 As shown.

[0075] Comparative Example 2

[0076] 2.1 g of a single dynamic crosslinked polymer was heated at 140 °C for 8 min, cooled, and ultrasonically dissolved in 24 ml of chloroform. Then, 0.9 g of liquid metal (gallium-indium alloy, Ga to In mass ratio of 75.5:24.5) was added, and ultrasonication was continued for 30 min to completely disperse the liquid metal in the polymer solution. The mixed solution was then poured into a tetrafluoroethylene mold and placed in an oven at 60 °C for 12 h to volatilize, resulting in a liquid metal composite material, denoted as OPU-LM30.

[0077] Results explanation:

[0078] The preparation process of the liquid metal composite material of the present invention is as follows: Figure 1 As shown.

[0079] like Figure 2 As shown, with the increase of liquid metal content in the composite material (i-vi represent 10%, 20%, 30%, 50%, 70%, and 90% of ODAPU-LM, respectively), the metallic luster on the surface of the composite material becomes more obvious. However, when the liquid metal content reaches 90%, the small amount of polymer matrix can no longer support a large amount of liquid metal. Therefore, 70% liquid metal content is the upper limit of the load of the composite material.

[0080] Furthermore, as shown in Table 1, the fracture stress and Young's modulus of the liquid metal composite material gradually decreased with increasing liquid metal content and decreasing content of the dual dynamic crosslinked polymer (polymer matrix), decreasing from 26.6 ± 0.26 MPa and 53.3 ± 1.2 MPa to 5.67 ± 0.38 MPa and 20.0 ± 0.6 MPa, respectively; while the strain increased with increasing liquid metal content, indicating that the flexibility of the liquid metal composite material gradually increased.

[0081] Table 1 Mechanical properties of liquid metal composite materials in Examples 1-5 and Comparative Example 1

[0082]

[0083] As shown in Table 2, it can be seen that with the increase of liquid metal content, the liquid metal composite material begins to exhibit conductivity at a 20% load and becomes stably self-conductive at a 30% load, without the need for additional sintering stimulation. The contact resistance is 2.5 ± 0.1 Ω and the conductivity is 4.6 ± 0.07 (*10) 5 The contact resistance gradually decreases and the conductivity gradually increases after reaching 0.6 ± 0.2 Ω at 70% load. The conductivity is 20 ± 0.2 (*10) S / m. 5 The S / m value indicates that the conductivity of the liquid metal composite material is positively correlated with the amount of liquid metal loaded.

[0084] Table 2. Electrical conductivity of liquid metal composite materials in Examples 1-5 and Comparative Example 1

[0085]

[0086] like Figure 3 As shown in Table 3, it can be seen that compared to single-dynamic crosslinked polymers, double-dynamic crosslinked polymers have a longer processing window, making them easier to composite with liquid metals. Liquid metal particles are more likely to aggregate in double-dynamic crosslinked networks to form percolating conductive networks; while in single-dynamic crosslinked polymers, the network only partially opens when stimulated, resulting in more liquid metal particles being locked in the network, leading to poorer conductive network connectivity and thus lower resistance and conductivity.

[0087] Table 3. Electrical conductivity of the liquid metal composite materials in Example 2 and Comparative Example 2

[0088]

[0089] like Figure 4 As shown, with the increase of liquid metal content in the liquid metal composite material (i, ii, and iii represent ODAPU-LM10%, ODAPU-LM20%, and ODAPU-LM30%, respectively), the asymmetric structure shows that the thickness of the liquid metal layer increases significantly, and the particles are more tightly packed, thus improving conductivity.

[0090] like Figure 5As shown in the planar optical micrographs, as the liquid metal content in the liquid metal composite increases, the gray-silver brightness of the composite surface increases, and the packing density of the liquid metal particles increases. In Comparative Example 1, the liquid metal particles on the surface are relatively dispersed and rarely contact each other, thus the surface is insulating. In Example 1, the liquid metal particles on the surface begin to contact each other, but because the liquid metal particles are wrapped by a double dynamic cross-linked polymer layer, the conductive path cannot be formed normally. With the help of mechanical force to break the wrapped double dynamic cross-linked polymer layer, the liquid metal is released, and thus the liquid metals contact each other to form a conductive path, which is called mechanically induced sintering conductivity. In Example 2, the liquid metal particles on the surface are tightly packed, and the reduced content of the double dynamic cross-linked polymer greatly reduces the coverage area of ​​the liquid metal, thus the liquid metal particles spontaneously form a conductive plane, achieving self-conductivity without external force stimulation.

[0091] like Figure 6 As shown, Comparative Example 1 still shows no resistance when measured at the maximum resistance range, indicating that it is an insulating material; Example 1, after mechanical sintering, shows an average resistance of about 22kΩ, and although the surface is conductive, the conductivity is poor; Example 2, after direct measurement, shows an average resistance of about 2.5Ω, with good conductivity, which meets the normal conductivity requirements.

[0092] like Figure 7 As shown, X-ray photoelectron spectroscopy (XPS) was used to characterize the interaction between the liquid metal and the dual dynamic crosslinked polymer. The binding energy of the CO single bond shifted from 284.6 eV to 286.5 eV, and the binding energy of the C=O double bond shifted from 288.8 eV to 288.9 eV. Meanwhile, the XPS plot of Example 2 showed a new peak at 397.1 eV for the binding energy of N 1s, indicating that the liquid metal and the dual dynamic crosslinked polymer material have a strong coupling interaction, which makes the composite material stable.

[0093] like Figure 8 As shown, the liquid metal composite material of Example 2 can maintain stable conductivity underwater, in high temperature (85°C) and ultra-low temperature (-196°C) environments, and the circuit connected by it can maintain a circuit, so that the light bulb can light up.

[0094] like Figure 9As shown, after thermal activation at 140℃ for 10 minutes, the liquid metal composite material was cooled to room temperature and then adhered to the substrate surface. The 180° peel strength was tested one day later. The results indicate that the adhesion performance of the liquid metal composite material to the substrate is highly correlated with the polarity of the substrate itself. The maximum peel strengths for highly polar epoxy resin (EP) and polycarbonate (PC) were 6.19 N / 20 mm and 2.8 N / 20 mm, respectively, while the maximum peel strengths for less polar polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) were 2.29 N / 20 mm and 1.72 N / 20 mm, respectively.

[0095] like Figure 10 As shown, the liquid metal composite material is shredded, added to a solvent, heated to dissolve, and then separated by centrifugation, which can realize the recovery of dynamic polymer and liquid metal.

Claims

1. A non-irritating, self-conductive liquid metal composite material, characterized in that, By mass percentage, the liquid metal composite material consists of 30-70% dual dynamic crosslinked polymer and 30-70% liquid metal; the liquid metal includes gallium-based liquid alloys. The structural formula of the dual dynamic crosslinked polymer is as follows: ； Where R represents a polyisocyanate residue; R1 represents a polyol residue; R2 represents a curing agent residue; and m = 2-600, n = 2-600. The dual dynamic crosslinked polymer is prepared from raw materials containing polyisocyanate, polyol, dynamic chain extender and curing agent, wherein the dynamic chain extender is dimethylglyoxime and furfurylamine; The preparation method of the non-irritating self-conductive liquid metal composite material includes: dissolving a dual dynamic cross-linked polymer in a solvent, adding liquid metal, mixing, removing the solvent, and obtaining a non-irritating self-conductive liquid metal composite material.

2. The non-irritating, self-conductive liquid metal composite material according to claim 1, characterized in that, The polyisocyanate includes one or more of aromatic polyisocyanates and aliphatic polyisocyanates; the polyol includes one or more of polyether polyols and polyester polyols; the curing agent includes one or more of N,N'-(4,4'-methylenediphenyl)bismaleimide and m-phenylenebismaleimide.

3. The non-irritating, self-conductive liquid metal composite material according to claim 1, characterized in that, The gallium-based liquid alloy is one or more of gallium-indium alloy, gallium-indium-tin alloy, and gallium-indium-tin-zinc alloy.

4. The non-irritating, self-conductive liquid metal composite material according to claim 1, characterized in that, The polyisocyanate includes one or more of aromatic polyisocyanates and aliphatic polyisocyanates; the polyol includes one or more of polyether polyols and polyester polyols; the curing agent includes one or more of N,N'-(4,4'-methylenediphenyl)bismaleimide and m-phenylenebismaleimide. The molar ratio of the polyisocyanate, polyol, dimethylglyoxime, furfuralamine, and curing agent is 1.08-3.63: 0.5-1.5: 0.2-1.0: 0.5-1.5: 0.25-0.

75.

5. The non-irritating, self-conductive liquid metal composite material according to claim 1, characterized in that, The preparation of the dual dynamic crosslinked polymer includes: dispersing dimethylglyoxime in a polyol at 50-80℃, adding polyisocyanate and reacting for 1-3 hours, then adding furfurylamine and continuing the reaction for 0.5-1 hours, raising the temperature to 100-120℃ and continuing the reaction for 10-12 hours, then adding a curing agent and continuing the reaction at 50-80℃ for 12-36 hours to obtain the dual dynamic crosslinked polymer.

6. A method for preparing a non-irritating, self-conductive liquid metal composite material as described in any one of claims 1-5, characterized in that, include: The dual dynamic crosslinked polymer was dissolved in a solvent, then liquid metal was added, mixed well, and the solvent was removed to obtain a non-irritating, self-conductive liquid metal composite material.

7. The preparation method according to claim 6, characterized in that, The solvent includes one or more of acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, ethyl acetate, butyl acetate, ethylene glycol ethyl ether acetate, dichloromethane, and chloroform. The dual dynamic cross-linked polymer is dissolved in a solvent, wherein the dissolution is ultrasonic dissolution; The mixing is ultrasonic mixing, and the ultrasonic time is 30-70 minutes; The solvent removal temperature is 50-80℃, and the time is 3-24h.

8. A method for recycling a non-irritating, self-conductive liquid metal composite material, characterized in that, include: The non-irritating, self-conductive liquid metal composite material of any one of claims 1-5 is mixed with a solvent, heated, centrifuged, and recovered to obtain a dual dynamic crosslinked polymer and liquid metal.

9. The application of the non-irritating, self-conductive liquid metal composite material of claim 1 in the fields of flexible wearables, sensing, micro-devices, and electronic device repair.

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