Liquid metal microarray anisotropic conductive adhesive film as well as preparation method and application thereof

Abstract

The invention relates to a liquid metal microarray anisotropic conductive adhesive film and a preparation method and application thereof, and the liquid metal microarray anisotropic conductive adhesive film comprises conductive particles and a non-conductive bonding matrix, the conductive particles are liquid metal micro-nano particles, and the conductive particles are distributed in the non-conductive bonding matrix in a periodic array manner. According to the anisotropic conductive adhesive film, the liquid metal serves as the conductive particles, the conductive particles are distributed in the non-conductive adhesive matrix in a periodic array mode, the contact resistance is low, the resistivity is as low as 0.303 m omega / mm < 2 >, the conductivity is improved by 20 times compared with that of a traditional anisotropic conductive adhesive film, and meanwhile due to the deformability of the liquid metal, the conductivity of the anisotropic conductive adhesive film is greatly improved. The anisotropic conductive adhesive film can be used for packaging flexible stretchable electronic devices.

Description

Technical Field

[0001] The present invention relates to the technical field of anisotropic conductive film, and particularly to a liquid metal microarray anisotropic conductive film, a preparation method thereof and an application thereof. Background Art

[0002] In the development of modern electronic devices, flexible electronic technology has received extensive attention due to its characteristics of being thin, light and bendable, and has shown great application potential especially in the fields of wearable devices, flexible displays, soft robots and the like. The commonly used material for electronic device packaging is anisotropic conductive film (ACF), which is composed of an adhesive matrix providing physical adhesion and conductive particles dispersed therein providing conductive performance, and can achieve electrical conduction in the Z-axis while insulating in the XY plane. The conductive particles used in traditional ACF are usually core-shell structure microspheres of metal-polymer. The ACF prepared with such particles may cause connection failure of the device during processes such as bending or stretching, and cannot meet the requirements of flexible electronic device packaging.

[0003] Liquid metal (LM) is a type of metal material that is liquid at room temperature or lower temperatures, has fluidity and good electrical conductivity. Adding it as a conductive filler to the ACF resin matrix is expected to be used for the packaging of flexible electronic devices. Young-Geun Park et al. uniformly dispersed LM particles in a gelatin matrix to prepare an ACF for the packaging of soft and free-form surface electronic products. At the same time, due to the characteristics of gelatin, self-healing and recycling of the ACF can be achieved. However, since the LM particles are randomly distributed in the gelatin matrix, the problem of short circuit between adjacent electrodes may occur when this ACF is used for fine pitch electrode packaging. Summary of the Invention

[0004] Based on this, aiming at the ACF for the packaging of soft and free-form surface electronic products prepared by uniformly dispersing LM particles in a gelatin matrix, since the LM particle size distribution is wide and the particles are randomly distributed in the gelatin matrix, the problem of short circuit between adjacent electrodes may occur when performing fine pitch electrode packaging. The purpose of the present invention is to provide a liquid metal microarray anisotropic conductive film, a preparation method thereof and an application thereof.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention first provides a liquid metal microarray anisotropic conductive film, which includes conductive particles and a non-conductive adhesive matrix. The conductive particles are liquid metal micro-nano particles and the conductive particles are distributed in a periodic array in the non-conductive adhesive matrix.

[0006] The anisotropic conductive adhesive film of the present invention uses liquid metal as conductive particles, and the conductive particles are distributed in a periodic array in a non-conductive adhesive matrix, having a low contact resistance and a resistivity as low as 0.303 mΩ / mm 2 . The conductivity of the present invention is 20 times higher than that of traditional ACF. At the same time, due to the deformability of liquid metal, the anisotropic conductive adhesive film of the present invention can be used for the encapsulation of flexible and stretchable electronic devices. The arrangement form of the conductive particles in the present invention is not particularly limited, including but not limited to a periodic array distribution in the shape of an equilateral triangle, a periodic array distribution in the shape of a square, and a periodic array distribution in the shape of a regular hexagon.

[0007] As a further improvement of the above solution of the present invention, the liquid metal micro-nano particles are obtained by bombarding a liquid metal bulk with ultrasonic energy; and / or, the non-conductive adhesive matrix is an epoxy resin or an acrylic resin; the epoxy resin is at least one of a naphthalene-type epoxy resin, a biphenyl-type epoxy resin, a fluorene-based epoxy resin, an alicyclic epoxy resin, a novolac-type epoxy resin, a bisphenol-type epoxy resin, a triphenolmethane-type epoxy resin, a phenol aralkyl-type epoxy resin, a dicyclopentadiene-type epoxy resin, and a triphenylmethane-type epoxy resin; the acrylic resin is at least one of methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethyloltricyclodecane diacrylate, butanediol tetraacrylate, 2-hydroxy-1,3-diacryloyloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxyethoxy)phenyl]propane, dicyclopentenyl acrylate, tricyclic acrylate, examples of which include decyl acrylate, tris(acryloxyethyl)isocyanurate, polyurethane acrylate, epoxy acrylate, and substances made of methacrylate from acrylate.

[0008] As a further improvement of the above solution of the present invention, the obtaining of liquid metal micro-nano particles by bombarding a liquid metal bulk with ultrasonic energy includes the following steps: dispersing the liquid metal bulk in a solvent, bombarding the solvent with ultrasonic waves, and centrifuging to obtain the liquid metal micro-nano particles. The solvent is deionized water, an aqueous solution containing a surfactant, or an organic solvent; the surfactant is at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium stearate, cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, tetramethylammonium chloride, polyethylene glycol fatty acid ester, octylphenol polyoxyethylene ether, polysorbate fatty acid ester, sodium lauroyl glutamate, dimethyl silicone betaine, and coconut oil amide propyl betaine; the organic solvent is ethanol, isopropyl alcohol, n-butanol, n-hexane, cyclohexane, acetone, cyclohexanone, or dimethylformamide.

[0009] As a further improvement of the above solution of the present invention, the conductive particles are in a liquid state at room temperature, and the conductive particles are gallium metal, gallium-indium alloy, gallium-tin alloy, gallium-aluminum alloy, gallium-zinc alloy, gallium-silver alloy, sodium-potassium alloy or tin-bismuth alloy.

[0010] The present invention also provides a method for preparing the liquid metal microarray anisotropic conductive adhesive film as described above, which includes the following steps: S1. Self-assemble liquid metal micro-nano particles into the holes of a periodic array hole template to obtain a periodic array hole template filled with liquid metal micro-nano particles; S2. Transfer the liquid metal micro-nano particles distributed in a periodic array in the periodic array hole template to a non-conductive adhesive matrix to obtain a liquid metal microarray anisotropic conductive adhesive film.

[0011] In the present invention, the material of the periodic array hole template is not particularly limited and can be silicon material, alumina, metal material, polymer material, silica, etc., such as single crystal silicon material, anodic aluminum oxide material, gold material, copper material, polystyrene material, polydimethylsiloxane material, polylactic acid material, glass, etc. The preparation method of the periodic array hole template is not particularly limited. For example, anodic oxidation method, nanoimprint technology, electron beam lithography technology, laser etching method, breath figure method, electrochemical corrosion method, self-assembly method, chemical vapor deposition method, etc. These methods can be used alone or in combination of two or more.

[0012] As a further improvement of the above solution of the present invention, step S1 specifically includes the following steps: S11. Disperse liquid metal micro-nano particles in deionized water to obtain a suspension; S12. Dropwise add an infiltration liquid and the suspension to the surface of the periodic array hole template successively, repeat several times, and then dry to obtain a periodic array hole template filled with aggregates of liquid metal micro-nano particles.

[0013] Through self-assembly by the template emulsion method, the present invention assembles the micro-nano liquid metal particles obtained by ultrasonic fragmentation into the periodic array hole template, and can perform multiple self-assemblies according to the hole size, thereby achieving complete filling of the holes, breaking through the limitation that the traditional template emulsion method self-assembly method cannot perform multiple self-assemblies. The size of the periodic array hole template is not particularly limited and can be customized according to requirements. In the present invention, the infiltration liquid is not particularly limited and can be a solution organic solvent with low surface tension, such as at least one of methanol, ethanol, acetone, and isopropanol. The number of repetitions in step S12 is not particularly limited and can be adjusted according to the size of the holes.

[0014] As a further improvement of the above solution of the present invention, step S1 further includes the following steps: S13. Drop an infiltration liquid and a chemical reaction liquid successively onto the surface of the periodic array hole template filled with the liquid metal micro-nano particle aggregates, and a periodic array hole template filled with the liquid metal micro-nano fusion body is obtained. Under natural conditions, a nano-thick oxide film will quickly form spontaneously on the surface of the LM. This oxide film prevents the fusion of the LM during mutual contact and helps break the LM bulk into micro-nano particles during the ultrasonic process. Since this oxide film is an amphoteric oxide, the chemical reaction liquid can destroy this oxide film. Without the oxide film, due to the high surface tension, the LMs will fuse into a whole in the periodic array hole template after mutual contact.

[0015] As a further improvement of the above solution of the present invention, the chemical reaction liquid is an acid solution or an alkali solution with a concentration of 0.05 - 2.0 M. The acid solution is hydrochloric acid solution, sulfuric acid solution, nitric acid solution, acetic acid solution or chloric acid solution, and the alkali solution is sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution or ammonium hydroxide solution.

[0016] As a further improvement of the above solution of the present invention, step S2 specifically includes the following steps: Place the periodic array hole template filled with the liquid metal micro-nano particles on a non-conductive adhesive matrix and cover it with a release film, perform hot embossing transfer at 40 - 120 °C using a roller hot embossing transfer instrument, cool down, and remove the periodic array hole template to obtain the liquid metal micro-array anisotropic conductive adhesive.

[0017] The present invention also provides an application of the liquid metal micro-array anisotropic conductive adhesive film as described above in the encapsulation of flexible and stretchable electronic devices.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The anisotropic conductive adhesive film of the present invention uses liquid metal as the conductive particles, and the conductive particles are distributed in a periodic array in the non-conductive adhesive matrix, having a low contact resistance and a resistivity as low as 0.303 mΩ / mm 2 . The conductivity is 20 times higher than that of the traditional ACF. At the same time, due to the deformability of the liquid metal, the anisotropic conductive adhesive film of the present invention can be used for the encapsulation of flexible and stretchable electronic devices.

[0019] 2. Based on the self-assembly of the template emulsion method, the present invention assembles micro-nano liquid metal particles into a periodic array of hole templates, and then transfers the liquid metal in the periodic array of hole templates to a non-conductive adhesive matrix by means of hot embossing transfer, obtaining an anisotropic conductive adhesive film of liquid metal microarrays. It can perform multiple self-assemblies according to the hole size, thereby achieving complete filling of the holes, realizing the control of the number of micro-nano liquid metal particles in the holes, making up for the limitation that the traditional template emulsion method can only perform single self-assembly and cannot increase the filling amount. Moreover, the distance between conductive particles can be regulated by the template, and hot embossing transfer can transfer the liquid metal to the non-conductive adhesive matrix while maintaining the spatial array of the liquid metal. The prepared anisotropic conductive adhesive film has good anisotropic conductive properties and can simultaneously achieve stable bonding of flexible and stretchable electronic devices.

[0020] 3. When preparing the anisotropic conductive adhesive film of liquid metal microarrays, under natural conditions, a nano-thick oxide film will quickly form spontaneously on the surface of the liquid metal. This oxide film prevents the fusion of liquid metal particles during the contact process and helps break the liquid metal particle mass into micro-nano particles during ultrasonic treatment. Since this oxide film is an amphoteric oxide, a chemical reaction solution is used to destroy the oxide film on the surface of the micro-nano liquid metal particles in the periodic array of hole templates. The liquid metal without the oxide film will fuse into a whole in the periodic array of hole templates due to the high surface tension after contact, thereby obtaining liquid metal microspheres with high size uniformity, narrowing the particle size distribution of the conductive particles of the anisotropic conductive adhesive film, which is beneficial to the realization of stable electrical transmission of the anisotropic conductive adhesive film.

[0021] 4. The micro-nano liquid metal particles of the present invention are obtained by bombarding a liquid metal mass with ultrasonic energy. The particle size is relatively large and the mass is relatively large. During multiple assembly processes, they can still resist the impact of the liquid during the self-assembly process and remain in the holes, thereby achieving multiple self-assemblies, making up for the limitation that the traditional template emulsion method can only perform single self-assembly of nano-scale particles and cannot increase the filling amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the SEM image of the micro-nano gallium-indium liquid metal particles prepared in the embodiment of the present invention; Figure 2 is the structural schematic diagram of the periodic array of hole templates filled with aggregates of micro-nano liquid metal gallium-indium particles prepared in the embodiment of the present invention; Figure 3 is the SEM image of the periodic array of hole templates filled with aggregates of micro-nano liquid metal gallium-indium particles prepared in the embodiment of the present invention; Figure 4Schematic structural diagram of a periodic array hole template filled with a micro-nano liquid metal gallium-indium fusant prepared in an embodiment of the present invention; Figure 5 SEM image of a periodic array hole template filled with a micro-nano liquid metal gallium-indium fusant prepared in an embodiment of the present invention; Figure 6 Test result diagram of the conductivity of anisotropic conductive adhesive films prepared in Examples 1-2 and Comparative Examples; Figure 7 Test result diagram of cyclic tensile test of a bonded sample prepared with the anisotropic conductive adhesive prepared in Example 2. Detailed implementation manners

[0023] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0025] Example 1 This example proposes a liquid metal microarray anisotropic conductive adhesive film, and its preparation steps are as follows: S1. Self-assemble liquid gallium-indium metal micro-nano particles into the holes of a periodic array hole template to obtain a periodic array hole template filled with liquid gallium-indium metal micro-nano particles. Specifically, it includes the following three steps S11-S13.

[0026] S11. Obtain liquid gallium-indium metal micro-nano particles by ultrasonic fragmentation: (1) Weighing of liquid gallium-indium metal bulk: Add 10 mL of deionized water to a reagent bottle, and use a syringe to weigh 0.1 g of liquid droplets of gallium-indium alloy (EGaIn) and drop them into the reagent bottle.

[0027] (2) Ultrasonic fragmentation of liquid gallium-indium metal bulk: Place the reagent bottle containing gallium-indium alloy liquid droplets in an ice bath, insert the ultrasonic generating device of the ultrasonic crusher into the reagent bottle and extend it below the liquid surface, and fragment the gallium-indium alloy bulk with 30% ultrasonic power for 30 min to obtain micro-nano liquid gallium-indium metal particles.

[0028] (3)Enhancement of the concentration of micro-nano liquid gallium-indium metal particles: Transfer the micro-nano liquid metal particles in the reagent bottle to a centrifuge tube, centrifuge at 6000 rpm for 5 min, remove the solution, and add 2.5 g of deionized water to obtain a suspension containing high-concentration micro-nano liquid gallium-indium metal particles. Figure 1 is the SEM image of the micro-nano liquid gallium-indium metal particles obtained in this example. From Figure 1 it can be seen that the bulk liquid metal is broken into micro-nano circular particles with sizes between 200 nm and 1200 nm under the bombardment of ultrasonic energy.

[0029] S12. Self-assembly of micro-nano liquid metal particles in the periodic array holes by the template emulsion method: (1)Wetting of the periodic array holes: Drop 10 μL of ethanol onto the periodic array hole template (made of polystyrene, with a hole diameter of 4.5 μm, a hole depth of 4.1 μm, the center distance between adjacent holes of 6.0 μm, and the holes arranged in a hexagonal array periodically). After 2 min, the ethanol is completely wet and enters the holes.

[0030] (2)Filling the holes with micro-nano liquid gallium-indium metal particles: Drop 10 μL of the suspension containing high-concentration micro-nano liquid gallium-indium metal particles onto the periodic array hole template wetted with ethanol. After 4 min, wait for the ethanol in the holes to diffuse into the micro-nano liquid metal particle dispersion system. At this time, the micro-nano liquid metal particle dispersion diffuses into the holes to complete the filling.

[0031] (3)Removing the excess suspension containing high-concentration micro-nano liquid gallium-indium metal particles: Take 1.0 mL of isopropanol and quickly flush the surface of the periodic array hole template. The excess micro-nano liquid gallium-indium metal particle suspension is flushed away, leaving a micro-emulsion of micro-nano liquid gallium-indium metal particles in the holes. Wait for the isopropanol to completely volatilize to complete the self-assembly of micro-nano liquid gallium-indium metal particles in the periodic array hole template.

[0032] S13. Increasing the content of micro-nano liquid gallium-indium metal particles in the holes by the multiple-template emulsion method: (1)Multiple wetting of the periodic array holes: Drop 10 μL of ethanol onto the periodic array hole template filled with micro-nano liquid metal particles. After 2 min, the ethanol is completely wet and enters the holes.

[0033] (2)Filling the holes with micro-nano liquid gallium-indium metal particles: 10 μL of the suspension containing high-concentration micro-nano liquid gallium-indium metal particles was dropped onto the periodic array hole template infiltrated with ethanol. After 4 min, when the ethanol in the holes diffused into the micro-nano liquid gallium-indium metal particle dispersion system, the micro-nano liquid gallium-indium metal particle dispersion diffused into the holes, and the content of micro-nano liquid gallium-indium metal particles in the holes increased.

[0034] (3)Removing the excess suspension containing high-concentration micro-nano liquid gallium-indium metal particles: 1.0 mL of isopropanol was taken and quickly flushed over the surface of the periodic array hole template. The excess suspension containing high-concentration micro-nano liquid gallium-indium metal particles was flushed away, leaving a micro-nano liquid gallium-indium metal particle microemulsion in the holes. After the isopropanol completely volatilized, the content of micro-nano liquid gallium-indium metal particles in the periodic array hole template increased, and thus micro-nano liquid metal gallium-indium particle aggregates were formed and filled in each hole of the periodic array hole template. Figure 2 is the structural schematic diagram of the periodic array hole template filled with micro-nano liquid metal gallium-indium particle aggregates obtained in this example; Figure 3 is the SEM image of the periodic array hole template filled with micro-nano liquid metal gallium-indium particle aggregates obtained in this example. From Figure 3 it can be seen that the template holes are filled with liquid metal micro-nano particle aggregates.

[0035] S2. Transferring the liquid gallium-indium metal micro-nano particle aggregates distributed in a periodic array in the periodic array hole template to a non-conductive adhesive matrix to obtain a liquid gallium-indium metal microarray anisotropic conductive adhesive film. Specifically, it includes: (1)Pre-laminating the non-conductive adhesive matrix: A 10.0 mm × 10.0 mm non-conductive adhesive matrix (purchased from Sino-European International Innovation Center for Electronic Materials (Hefei) Co., Ltd., model RD1220) was laminated on an indium tin oxide (ITO) substrate and placed under a roller-type hot press instrument to complete the pre-lamination at 50 °C.

[0036] (2)Transferring the liquid gallium-indium metal particles in the periodic array hole template: The periodic array hole template filled with liquid gallium-indium metal aggregates was placed on the surface of the non-conductive adhesive matrix and placed under a roller-type hot press instrument to complete the transfer of the liquid gallium-indium metal particles at 60 °C.

[0037] (3)Removing the periodic array hole template: After the non-conductive adhesive matrix was cooled to room temperature, the periodic array hole template was peeled off, and the liquid gallium-indium metal aggregates in the holes were left, obtaining a liquid gallium-indium metal micro-nano array anisotropic conductive adhesive film, denoted as ALM-ACF.

[0038] Example 2 This embodiment adopts the same implementation method as Embodiment 1. The difference from Embodiment 1 is as follows: Step S1 of this embodiment further includes the following step S14: S14. Fusion of micro-nano liquid gallium-indium metal particles in the holes: (1) Preparation of acidic solution: Measure 1.0 mL of hydrochloric acid aqueous solution into a beaker, add 9.0 mL of deionized water for dilution, and stir evenly to obtain the acidic solution.

[0039] (2) Infiltration of periodic array holes: Take 10 μL of ethanol and drop it onto the periodic array hole template filled with micro-nano liquid gallium-indium metal particle aggregates. After 2 minutes, the ethanol is completely infiltrated and enters the holes.

[0040] (3) Introduction of acidic solution into the holes: Take 10 μL of acidic solution and drop it onto the periodic array hole template infiltrated with ethanol. After the acidic solution diffuses into the holes, the oxide film on the surface of the micro-nano liquid metal particles reacts when they contact the alkaline solution, and they gradually fuse into a whole after coming into contact with each other, completing the fusion of micro-nano liquid gallium-indium metal particles.

[0041] (4) Removal of excess acidic solution: Take 1.0 mL of isopropanol and quickly sweep the surface of the periodic array hole template. The excess acidic solution is swept away. After the isopropanol completely volatilizes, the liquid gallium-indium metal particles fused into a whole are left in the holes. Figure 4 is the structural schematic diagram of the periodic array hole template filled with the micro-nano liquid metal gallium-indium fusion body obtained in this embodiment; Figure 5 is the SEM image of the periodic array hole template filled with the micro-nano liquid metal gallium-indium fusion body obtained in this embodiment. It can be seen from Figure 5 that the liquid metal micro-nano particles in the holes are fused into a whole.

[0042] Step S2 of this embodiment is: S2. Transfer the liquid gallium-indium metal micro-nano particles distributed in a periodic array in the periodic array hole template to a non-conductive adhesive matrix, and then the liquid gallium-indium metal microarray anisotropic conductive adhesive film is obtained. Specifically, it includes: (1) Pre-laying of ACF adhesive matrix: Take a 10.0 mm × 10.0 mm non-conductive adhesive matrix (purchased from Central Europe International Innovation Center for Electronic Materials (Hefei) Co., Ltd., model RD1220) and lay it on an indium tin oxide (ITO) substrate, and place it under a roller-type hot pressing instrument to complete the pre-laying under the condition of 50 °C.

[0043] (2) Transfer of the liquid gallium-indium metal fusion in the periodic array hole template: Place the liquid gallium-indium metal fusion prepared in step S1 on the surface of a non-conductive adhesive substrate, and place it under a roller-type hot pressing instrument. Complete the transfer of the liquid gallium-indium metal fusion at 60 °C.

[0044] (3) Removal of the periodic array hole template: After cooling the non-conductive adhesive substrate to room temperature, peel off the periodic array hole template, and the liquid gallium-indium metal particles in the holes are left behind, obtaining a liquid gallium-indium metal micro-nano array anisotropic conductive adhesive film, denoted as MLM-ACF.

[0045] Comparative example In this comparative example, an anisotropic conductive adhesive film commercially purchased from Zhongou International Innovation Center for Electronic Materials (Hefei) Co., Ltd., model ACO019, was used. This anisotropic conductive adhesive film includes conductive particles and a non-conductive adhesive substrate (model RD1220). The conductive particles are arranged in a periodic array in the adhesive matrix, and core-shell structured conductive microspheres are used as the conductive particles, where the core is a polymer material (material: polystyrene) and the shell layer is a conductive metal Ni material. This anisotropic conductive adhesive film is denoted as Ni-ACF.

[0046] Test example Conductivity tests were carried out on ALM-ACF, MLM-ACF, and Ni-ACF respectively, and the results are as Figure 6 shown. It can be seen from Figure 6 that compared with the traditional Ni-ACF using core-shell structured microspheres as conductive particles, the conductivity of the ACF of the fused LM prepared in Examples 1-2 is increased by more than 20 times.

[0047] The anisotropic conductive adhesive film MLM-ACF prepared in Example 2 was used for the bonding of flexible and stretchable devices: Under the hot pressing bonding conditions of 110 °C and 90 s, the anisotropic conductive adhesive film was tested by ACF bonding cyclic stretching to obtain a bonded sample; the bonded sample was subjected to multiple cyclic stretching tests: Cyclic stretching test method: Use a universal testing machine (AGS-X, Shimadzu Co., Ltd.) to perform cyclic stretching deformation on the bonded sample, and use an electrochemical workstation to detect the current change. The test results are as Figure 7 shown. It can be seen from Figure 7 that the samples bonded with MLM-ACF show almost unchanged resistance characteristics, indicating that the liquid metal microarray ACF can be used for the bonding of flexible and stretchable devices.

[0048] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification.

[0049] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A liquid metal microarray anisotropic conductive adhesive film, comprising conductive particles and a non-conductive adhesive matrix, characterized in that: The conductive particles are liquid metal micro-nano particles and are distributed in the non-conductive bonding matrix in a periodic array.

2. The liquid metal microarray anisotropic conductive adhesive film according to claim 1, characterized in that: The liquid metal micro-nano particles are obtained by bombarding a liquid metal block with ultrasonic energy; And / or, the non-conductive adhesive matrix is ​​epoxy resin or acrylic resin; the epoxy resin is at least one of naphthalene epoxy resin, biphenyl epoxy resin, fluorene epoxy resin, alicyclic epoxy resin, novolac epoxy resin, bisphenol epoxy resin, trisphenol methane epoxy resin, phenol aralkyl epoxy resin, dicyclopentadiene epoxy resin, and triphenylmethane epoxy resin; the acrylic resin is methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol Examples of the present invention include at least one of decyl acrylate, tris(acryloyloxyethyl)isocyanurate, polyurethane acrylate, epoxy acrylate, and methacrylates made from acrylates.

3. The liquid metal microarray anisotropic conductive adhesive film according to claim 2, characterized in that: The method of obtaining liquid metal micro-nano particles by bombarding a liquid metal block with ultrasonic energy comprises the following steps: dispersing the liquid metal block in a solvent, bombarding the solvent with ultrasonic waves, and centrifuging to obtain liquid metal micro-nano particles.

4. The liquid metal microarray anisotropic conductive adhesive film according to claim 1, characterized in that: The conductive particles are in liquid state at room temperature, and are gallium metal, gallium-indium alloy, gallium-tin alloy, gallium-aluminum alloy, gallium-zinc alloy, gallium-silver alloy, sodium-potassium alloy or tin-bismuth alloy.

5. A method for preparing the liquid metal microarray anisotropic conductive adhesive film according to any one of claims 1 to 4, characterized in that: It includes the following steps: S1. self-assembling liquid metal micro-nanoparticles into the holes of the periodic array hole template to obtain a periodic array hole template filled with liquid metal micro-nanoparticles; S2. Transferring the liquid metal micro-nanoparticles distributed in a periodic array in the periodic array hole template to a non-conductive adhesive substrate to obtain a liquid metal microarray anisotropic conductive adhesive film.

6. The method for forming anisotropic conductive film of liquid metal microarray according to claim 5, characterized in that: Step S1 specifically includes the following steps: S11. dispersing liquid metal micro-nanoparticles in deionized water to obtain a suspension; S12. dripping the infiltration liquid and the suspension onto the surface of the periodic array hole template successively, repeating for several times, and drying to obtain a periodic array hole template filled with liquid metal micro-nano particle agglomerates.

7. The method for forming anisotropic conductive film of liquid metal microarray according to claim 6, characterized in that: Step S1 also includes the following steps: S13. Adding an infiltration liquid and a chemical reaction liquid to the surface of the periodic array hole template filled with liquid metal micro-nano particle agglomerates, thereby obtaining a periodic array hole template filled with liquid metal micro-nano fusion bodies.

8. The method for forming anisotropic conductive film of liquid metal microarray according to claim 7, characterized in that: The chemical reaction liquid is an acid solution or an alkali solution with a concentration of 0.05-2.0M, the acid solution is a hydrochloric acid solution, a sulfuric acid solution, a nitric acid solution, an acetic acid solution or a chloric acid solution, and the alkali solution is a sodium hydroxide solution, a potassium hydroxide solution, a lithium hydroxide solution or an ammonium hydroxide solution.

9. The method for forming anisotropic conductive film of liquid metal microarray according to claim 8, characterized in that: Step S2 specifically includes the following steps: placing the periodic array hole template filled with liquid metal micro-nanoparticles on a non-conductive adhesive substrate and covering it with a release film, performing hot pressing transfer at 40-120° C. using a roller hot pressing transfer instrument, cooling, and removing the periodic array hole template to obtain a liquid metal microarray anisotropic conductive adhesive.

10. Use of the liquid metal microarray anisotropic conductive adhesive film according to any one of claims 1 to 4 in the packaging of flexible and stretchable electronic devices.

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