A flexible, stretchable laminated composite structure comprising a liquid metal

Abstract

A flexible stretchable laminated composite structure containing liquid metal, comprising a first elastic layer, a liquid metal layer and a second elastic layer in sequence; the surface of the first elastic layer facing the second elastic layer is bonded with a plurality of support bodies, and / or the surface of the second elastic layer facing the first elastic layer is bonded with a plurality of support bodies; the liquid metal layer fills the remaining space between the first elastic layer and the second elastic layer. The laminated composite structure formed by the elastic layer and the liquid metal interlayer, and the support bodies, can provide a flexible stretchable packaging member with excellent sealing performance, effectively preventing the problem of packaging failure caused by the reduction of barrier performance due to the contact between the two elastic layers caused by stretching or bending during use. Based on the composite structure and the packaging member, a packaging method is also provided, which can provide effective, long-term and stable packaging performance for various structures and sizes of the to-be-packaged objects, especially the to-be-packaged objects that need to be stretched and deformed in later applications.

Description

Technical Field

[0001] This invention belongs to the field of packaging technology, and particularly relates to a flexible and stretchable layered composite structure containing liquid metal, a package having the flexible and stretchable layered composite structure, and a packaging method for manufacturing the package. Background Technology

[0002] Flexible and stretchable electronics technology, based on flexible materials, using flexible electronic devices as a platform, and incorporating optoelectronic applications, is a disruptive scientific and technological innovation formed on the basis of a high degree of interdisciplinary integration of physics, chemistry, materials science and engineering, optical engineering, and biomedical engineering. Compared to traditional electronic devices, flexible and stretchable electronic devices have greater flexibility and can adapt to different working environments to a certain extent, meeting the deformation requirements of equipment.

[0003] However, the corresponding technical requirements also constrain the development of flexible and stretchable electronics technology. Besides the new challenges and requirements placed on materials for fabrication due to the stretchability and bendability of flexible electronic devices without compromising their electronic properties, the packaging materials and structures of flexible electronic devices, while meeting basic packaging requirements, also need to provide long-term stable packaging performance under external forces such as stretching and bending. Traditional rigid electronic devices are encapsulated in packaging materials to keep active substances (such as oxygen and water) away from sensitive materials within the device, thereby ensuring long-term stability. However, stretchable devices and systems lack effective stretchable gas-barrier packaging. Stretchable materials, such as elastomers, are easily permeable by gases due to their large void volume and the highly mobile nature of their polymer chains. Current methods to address the challenges of stretchable packaging technology mainly focus on combining low Young's modulus materials with high gas permeability (such as elastomers) with high Young's modulus materials with low gas permeability (such as inorganic or metallic materials), but the resulting composite materials either have limited stretchability or limited sealing performance. Patent application CN115551709A discloses a moisture-barrier laminated film comprising a plastic film (A) having an inorganic barrier layer (A1) and a moisture-capturing layer (B) containing an alkaline component, with a coating layer (C) disposed between the inorganic barrier layer (A1) and the moisture-capturing layer (B). The inorganic barrier layer (A1) can be formed by plasma CVD or other vapor deposition methods and is formed from oxides of Al and Si. This moisture-barrier laminated film can constitute a sealing material for electronic devices. The laminated film of this invention has a complex composition and structure, employing a combination of inorganic and organic barrier methods, resulting in low stretchability. If the device is stretched or bent during transportation or use, the barrier structure, including the inorganic barrier layer, is easily damaged, leading to a decrease in the barrier performance of the laminated film.

[0004] Besides the aforementioned inorganic oxide materials, metal layers are also commonly used barrier materials. For example, aluminum and steel have excellent gas barrier properties and can be used in the food industry for canned foods and packaging liners (e.g., potato chip bags). However, metals are generally non-ductile. Patent CN104205407B discloses a lithium-ion battery encapsulation material having a substrate layer composed of a resin film and a first adhesive layer, a metal foil layer, an anti-corrosion treatment layer, a second adhesive layer, and a sealing layer sequentially stacked on one side of the substrate layer. The water absorption rate of the resin film in the test specified in JIS K 7209:2000 is 0.1% to 3%. In the tensile test, when the specimen is stretched by 10% relative to its length before the tensile test, the stress value in the MD direction and the stress value in the TD direction of the specimen are both 110 MPa or less, and at least one of the stress values ​​in the MD direction and the stress values ​​in the TD direction of the specimen is 70 MPa or more. Patent application CN105848882A discloses a metal encapsulation material with excellent heat dissipation, its preparation method, and a flexible electronic device encapsulated using the metal encapsulation material. The material forms a coating containing a metal-graphite composite on one side, thus providing a metal encapsulation material with excellent flexibility, moisture resistance, processability, and heat dissipation, as well as a flexible electronic device encapsulated using the metal encapsulation material. While the above invention can achieve good encapsulation performance under static or certain tensile conditions, because its coating uses a rigid material, when the tension exceeds the coating's tolerance, irreversible damage from external forces will lead to the loss of encapsulation performance.

[0005] Liquid metal (LM) is an exception, possessing the dual properties of both metal and fluid, thus offering an opportunity for stretchable, gas-barrier encapsulation. Simultaneously, liquid metal should exhibit gas barrier properties similar to metals, while its Young's modulus is significantly lower than that of ordinary elastomers with limited gas barrier properties. This combination of low Young's modulus and low permeability makes liquid metal an ideal choice for stretchable, gas-barrier encapsulation. However, liquid metal encapsulation structures may suffer from interlayer structural instability due to excessive deformation, leading to seal failure. Furthermore, flexible devices operating under normal or deformed conditions (tension, bending, torsion) are inevitably subjected to localized pressure; under these conditions, liquid metal encapsulations fail more rapidly and have a shorter lifespan.

[0006] Therefore, how to utilize the characteristics of liquid metal to provide long-term stable and high-performance packaging structures and simple process methods for flexible electronic devices and other devices with flexible stretching application requirements has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of the existing technology, the present invention aims to provide a flexible and stretchable layered composite structure comprising liquid metal, a package having the flexible and stretchable layered composite structure, and a packaging method for manufacturing the package. The use of liquid metal effectively fills the gap in stretchable, gas-tight packaging technology in the packaging field, thereby improving the service life of stretchable and flexible devices.

[0008] Specifically, the present invention provides a flexible and stretchable layered composite structure containing liquid metal, comprising a first elastic layer, a liquid metal layer, and a second elastic layer in sequence; a plurality of supports are bonded to the surface of the first elastic layer facing the second elastic layer, and / or a plurality of supports are bonded to the surface of the second elastic layer facing the first elastic layer; the liquid metal layer fills the remaining space between the first elastic layer and the second elastic layer.

[0009] The first and second elastic layers ensure the flexibility and ductility of the composite structure, while the liquid metal layer filling between them ensures that the composite structure maintains extremely high airtightness under normal operating temperatures. Furthermore, considering the frequent deformation of the flexible packaging structure, the two elastic layers may frequently come into close contact under pressure. Therefore, a support structure is provided to prevent them from sticking together as much as possible, ensuring that the liquid metal fills the space between the two elastic layers, thus guaranteeing airtightness. Moreover, before the liquid metal is filled, the two elastic layers may also stick together due to gravity, compression, or even slight adhesion due to intermolecular forces, preventing the liquid metal from fully filling. The support structure prevents these situations before and during filling.

[0010] This invention demonstrates a flexible, stretchable, gas-barrier encapsulation composite structure based on liquid metal by bonding a support to an elastic layer. This structure exhibits low gas permeability, blocking the passage of gases such as oxygen, water, and ethanol. Furthermore, the metallic, thermal, chemical, and electrical properties of liquid metal can be further utilized to endow the composite structure with additional functionality, particularly providing a promising pathway for long-term stable operation of stretchable, flexible devices.

[0011] Furthermore, the liquid metal in the liquid metal layer is selected from at least one of gallium-based liquid metals, indium-based liquid metals, and bismuth-based liquid metals. The use of a liquid metal layer fully utilizes the metallic and room-temperature fluid properties of liquid metals, providing crucial conditions for flexible, stretchable, and excellent sealing properties in packaging. Unlike solid metals, whose limited stretchability prevents them from meeting the requirements of flexible device packaging, the use of liquid metals effectively overcomes the technical obstacles of existing technologies that struggle to simultaneously achieve both sealing and stretchability, opening up broader application possibilities for flexible packaging.

[0012] Furthermore, the thickness of the first elastic layer is 0.001-10 mm, and the thickness of the second elastic layer is 0.001-10 mm; the first elastic layer and / or the second elastic layer includes at least one of natural rubber, synthetic rubber, ionogel, and hydrogel. Based on a thorough understanding and utilization of the properties of liquid metal, its effective use is key to industrialization. To this end, this invention specifically designs an elastic encapsulation shell to define the shape of the amorphous liquid metal, thereby enabling it to have dimensional and shape design flexibility to meet actual production and usage needs. This allows for the industrial application of liquid metal in the encapsulation field. Through extensive testing and summarizing empirical data, the thickness of the first and second elastic layers is limited to the aforementioned thicknesses, simultaneously ensuring airtightness and strength under normal use, making it suitable for various application scenarios.

[0013] Furthermore, the support is made of a low-permeability material and has a shape that is at least one of a sphere, ellipsoid, cylinder, cube, or cuboid. For ease of bonding and patterning, and for safety under stress conditions, a sphere is preferred, as it has smaller dimensional differences in all directions, resulting in better support uniformity and stability.

[0014] Furthermore, the low-permeability material is selected from at least one of metals, inorganic non-metals, or composites thereof. Depending on the primary purpose of the support structure, under increased external force, the elastic layers approach each other, and the support spacer acts as a support interval between the two elastic layers. The low permeability of the support itself and the low permeability of the liquid metal in the support gaps substantially increase the external force threshold for contact between the elastic layers. Low-permeability materials are commonly used in the encapsulation field, such as inorganic materials like metals, metal oxides, metal nitrides, and carbon materials.

[0015] Furthermore, the support body is a sphere arranged in an array pattern on the first elastic layer and / or the second elastic layer. The diameter D of the sphere is 0.01-1 mm, and the spacing H between adjacent spheres satisfies 0 ≤ H ≤ 10D. The spacing is the shortest distance between the outer surfaces of adjacent support bodies when the first elastic layer and / or the second elastic layer are laid flat.

[0016] Secondly, based on the aforementioned flexible and stretchable layered composite structure, the present invention provides a packaging component, comprising:

[0017] The inner encapsulation structure is formed by a second elastic layer surrounding and sealing the object to be encapsulated;

[0018] An outer encapsulation structure is formed by a first elastic layer surrounding and sealing the inner encapsulation structure; and a plurality of supports are bonded to the surface of the first elastic layer facing the second elastic layer, and / or a plurality of supports are bonded to the surface of the second elastic layer facing the first elastic layer;

[0019] The intermediate structure is formed by filling the remaining space between the inner and outer packaging structures with a liquid metal layer.

[0020] Through the design of the above-mentioned inner packaging structure, intermediate structure and outer packaging structure, the liquid metal can wrap the stretchable device in all directions of 360°, taking into account both flexibility and airtightness, thereby achieving gas-liquid barrier and ensuring the long-term stability and safety of the internal device.

[0021] Furthermore, under a tensile stress of 5-20%, the oxygen permeability of the encapsulation is 2.5 × 10⁻⁶. -6 cc / day / cm 2 Below, the water vapor transmission rate is 4.0 × 10⁻⁶. -7 cc / day / cm 2 the following.

[0022] Thirdly, the present invention also provides a packaging method for manufacturing the package, comprising the following steps:

[0023] Step 1: Adhere the support to one surface of the first elastic layer and / or one surface of the second elastic layer;

[0024] Step 2: Surround and seal the object to be packaged with a second elastic layer to form an inner packaging structure;

[0025] Step 3: Surround and seal the inner sealing structure with the first elastic layer to form an outer encapsulation structure; and make the surface of the first elastic layer with the support face the second elastic layer, and / or the surface of the second elastic layer with the support face the first elastic layer;

[0026] Step 4: Inject liquid metal into the remaining space between the inner and outer packaging structures through the liquid metal inlet reserved on the first elastic layer to form an intermediate structure; seal the liquid metal inlet.

[0027] Furthermore, in step one, the method of bonding the support to the first elastic layer and / or the second elastic layer includes the following steps:

[0028] S1.1: Attach the heat release tape to the bottom of the screen, pour several supports down from above the screen, let them pass through the screen and remain on the heat release tape, forming an array pattern;

[0029] S1.2: Apply uncured adhesive to one surface of the first elastic layer and / or one surface of the second elastic layer, and attach the side of the heat-release tape with the support to the adhesive-coated surface of the first elastic layer and / or the second elastic layer; heat and cure the adhesive, and release the support from the heat-release tape, so that the support is bonded to the surface of the first elastic layer and / or the second elastic layer.

[0030] By selecting the mesh structure of the screen, the support can be easily formed into an array pattern according to the size, spacing, and characteristics of the array pattern. The heat-release transfer printing method facilitates continuous, large-scale automated production.

[0031] This invention includes at least the following technical advantages:

[0032] (1) By fully utilizing the metallic and fluid properties of liquid metal and combining it with the coverage of an elastic outer layer, a flexible, stretchable, and gas-tight layered composite structure and its encapsulation are obtained. The encapsulation can be well applied to various devices with flexible stretching requirements, such as stretchable systems with volatile liquids (including water and organic liquids) and stretchable systems for electronic components with high airtightness requirements.

[0033] (2) The support structure can effectively support and disperse the pressure of the elastic layer, prevent the elastic layers from becoming unstable or coming into contact with each other due to excessive deformation, and prevent the single barrier of the elastic layer from occurring. This prevents the seal from failing and ensures that the packaging system has both good stretchability and long-term stable sealing barrier performance, providing the possibility and simple packaging operation for sealing devices with large deformation. Attached Figure Description

[0034] The above and other objects, features, and advantages of exemplary embodiments of this disclosure will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Figure 1-5 Several embodiments of this disclosure are shown in the text by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0035] Figure 1 This is a schematic diagram of the flexible, stretchable layered composite structure containing liquid metal of the present invention.

[0036] Figure 2 This is a schematic diagram of the forces acting on the composite structure of the present invention;

[0037] Figure 3 This is a schematic diagram of the packaging method of the package body of the present invention;

[0038] Figure 4 This is an exploded view of the package structure of the present invention;

[0039] Figure 5 Yes Figure 4 Enlarged optical microscope images of region A with respect to the support array pattern (VHX-1000, KEYENCE), (a) top view, (b) cross-sectional view.

[0040] Explanation of reference numerals in the attached drawings: 1. First elastic layer, 2. Second elastic layer, 3. Liquid metal layer, 4. Support, 5. Object to be encapsulated, 6. Liquid metal inlet, 100. Composite structure, 200. Encapsulation body, 201. Inner encapsulation structure, 202. Outer encapsulation structure. Detailed Implementation

[0041] To better understand the technical solution of this invention, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0042] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0043] The serial numbers assigned to components in this article, such as "first" and "second," are used only to distinguish the objects being described and do not imply any order or technical meaning.

[0044] In a first aspect, a flexible, stretchable, layered composite structure 100 comprising liquid metal includes, in sequence, a first elastic layer 1, a liquid metal layer 3, and a second elastic layer 2. A plurality of supports 4 are bonded to the surface of the first elastic layer 1 facing the second elastic layer 2, and / or a plurality of supports 4 are bonded to the surface of the second elastic layer 2 facing the first elastic layer 1. The liquid metal layer 3 fills the remaining space between the first elastic layer 1 and the second elastic layer 2. Optionally, the supports 4 are bonded to the surface of either the first elastic layer 1 or the second elastic layer 2, wherein the latter supports 4 are bonded to both elastic layers, so that the supports are all located within the space between the first elastic layer 1 and the second elastic layer 2. In various scenarios, especially in dynamic environments with external forces, this provides support and barrier functions for the space, ensuring that the liquid metal effectively performs its barrier function.

[0045] The liquid metal in the liquid metal layer 3 is selected from at least one of gallium-based liquid metals, indium-based liquid metals, and bismuth-based liquid metals. Specifically, the liquid metal is selected from at least one of metallic gallium, gallium-indium alloys, gallium-aluminum alloys, gallium-zinc-gold alloys, gallium-silver alloys, gallium-indium-tin alloys, gallium-indium-tin-zinc alloys, or other gallium-based liquid metals; indium-bismuth alloys, indium-tin alloys, indium-tin-bismuth alloys, bismuth-lead-tin-cadmium alloys, bismuth-lead-tin-cadmium alloys, bismuth-lead-tin-cadmium-indium alloys, etc., which are liquid and have metallic bonds. The base metal content is above 70 wt%. Preferably, the liquid metal is a eutectic gallium-indium alloy (EGaIn), with a gallium content of 70-80 wt% and an indium content of 20-30 wt%.

[0046] The thickness of the first elastic layer 1 is 0.001-10 mm, preferably 0.01-2 mm, more preferably 0.1-1 mm; the thickness of the second elastic layer 2 is 0.001-10 mm, preferably 0.01-5 mm, more preferably 0.1-2 mm; the specific thicknesses of the first and second elastic layers can be selected and adjusted according to the actual packaging shape, size and application environment. Comparatively, it is preferred that the thickness of the second elastic layer 2 is greater than or equal to the thickness of the first elastic layer 1; the first elastic layer 1 and / or the second elastic layer 2 include at least one of a natural rubber layer, a synthetic rubber layer, an ionogel layer, and a hydrogel layer. Specifically, the first elastic layer 1 and the second elastic layer 2 can be selected from a silicone rubber layer (such as a cross-linked polydimethylsiloxane (PDMS) layer or an Ecoflex layer), a natural rubber layer, a butyl rubber layer, or a nitrile rubber layer, or a chlorinated butyl rubber layer, or a chloroprene rubber layer, or a fluororubber layer, or a cis-butadiene rubber layer, or a polyurethane (TPU) layer, or other synthetic rubber layers, ionogel layers, hydrogel layers, or other stretchable elastic layers. Preferably, a silicone rubber layer is used; more preferably, PDMS is used, wherein the weight mixing ratio between the PDMS basic component and the curing agent is (8-12):1.

[0047] The support 4 is made of a low-permeability material and is at least one of the following shapes: sphere, ellipsoid, cylinder, cube, and cuboid; a sphere is preferred. The low-permeability material is selected from at least one of metals, inorganic non-metals, or composite materials thereof. Low-permeability materials are commonly used in the packaging field, such as inorganic materials like metals, metal oxides, metal nitrides, and carbon materials. Specifically, metals can be selected from copper, stainless steel, iron, chromium, titanium, vanadium, germanium, nickel, calcium, cobalt, manganese, and scandium, or metal composite materials; or carbon materials such as graphite; or ceramic materials such as aluminum nitride, boron oxide, silicon nitride ceramics, polycrystalline diamond ceramics, silicon carbide ceramics, alumina ceramics, boron nitride ceramics, and silicon materials. Considering the availability and cost of raw materials, glass beads are preferred.

[0048] The support 4, such as glass beads, is preferably arranged in an array pattern on the first elastic layer 1 and / or the second elastic layer 2. The diameter D of the glass beads is 0.01-1mm, preferably 0.1-0.5mm. The spacing H between adjacent beads satisfies 0≤H≤10D, preferably D / 2≤H≤8D, and more preferably D / 2≤H≤6D. The specific spacing value can be selected and adjusted according to the actual packaging shape, size, liquid metal usage, and application environment. The spacing between the beads should not be too large, for example, H>10D. Especially when it is above 20D, although the static barrier effect is small, the support barrier effect of the support 4 will be significantly reduced when subjected to dynamic forces such as stretching and bending. When it is above 50D, the support barrier effect can be basically ignored. Once the liquid metal usage is low, the elastic layers can easily come into contact, resulting in the loss of barrier effect. Herein, the spacing H is the shortest distance between the outer surfaces of two glass beads when the first elastic layer or the second elastic layer is laid flat in its natural state. When supports are provided on both the first elastic layer 1 and the second elastic layer 2, their array patterns can be designed accordingly to prevent the supports from being damaged due to excessive mutual force when subjected to external stretching or bending.

[0049] Secondly, a package 200 having the aforementioned flexible and stretchable layered composite structure includes: an inner package structure 201 formed by a second elastic layer 2 surrounding and sealing the object to be packaged 5; an outer package structure 202 formed by a first elastic layer 1 surrounding and sealing the inner package structure 201; and a plurality of supports 4 are bonded to the surface of the first elastic layer 1 facing the second elastic layer 2, and / or a plurality of supports 4 are bonded to the surface of the second elastic layer 2 facing the first elastic layer 1; and an intermediate structure formed by a liquid metal layer 3 filling the remaining space between the inner package structure 201 and the outer package structure 202.

[0050] The packaging method based on the aforementioned package specifically includes the following steps:

[0051] Step 1: Adhere the support 4 to one surface of the first elastic layer 1 and / or one surface of the second elastic layer 2, including the following steps:

[0052] S1.1: Apply heat-release tape to the bottom of the screen, and pour several supports 4 down from above the screen, leaving them on the heat-release tape through the screen and forming an array pattern; the screen has several square holes, which are selected according to the size of the supports 4 and the required spacing of the array pattern; for example, a screen with a square hole side length slightly larger than the size of the supports 4 is selected, so that only one support 4 remains on the heat-release tape at one position, thereby forming a satisfactory array pattern on the surface of the first elastic layer 1 and / or the second elastic layer 2;

[0053] S1.2: Apply uncured adhesive to one surface of the first elastic layer 1 and / or one surface of the second elastic layer 2, and attach the side of the heat-release tape with the support 4 to the adhesive-coated surface of the first elastic layer 1 and / or the second elastic layer 2; heat to cure the adhesive, and release the support 4 from the heat-release tape, so that the support 4 adheres to the surface of the first elastic layer 1 and / or the second elastic layer 2; the adhesive curing and heat release process specifically includes:

[0054] S1.2.1 Curing adhesive: Curing at 70-90℃ for 30-90 minutes; oven curing is preferred.

[0055] S1.2.2 Heat release: Heat to 100-120℃ and release the support from the heat release tape;

[0056] Step 2: Surround and seal the object to be packaged 5 with the second elastic layer 2 to form an inner packaging structure 201; Optionally, the inner packaging structure 201 may be further processed according to the performance and application requirements of the object to be packaged 5, for example, by evacuating the inner packaging structure 201 through the air extraction port reserved on the second elastic layer 2 and then sealing the air extraction port, or by injecting liquid into the inner packaging structure 201 through the reserved liquid injection port and then sealing the liquid metal inlet 6; Optionally, the inner packaging structure 201 may be formed by winding and bonding a single piece of the second elastic layer, or by butt-bonding two or more pieces of the second elastic layer.

[0057] Step 3: Surround and seal the inner packaging structure 201 with the first elastic layer 1 to form the outer packaging structure 202; and make the surface of the first elastic layer 1 with the support 4 facing the second elastic layer 2, and / or the surface of the second elastic layer 2 with the support 4 facing the first elastic layer 1; Optionally, a single piece of the first elastic layer 1 can be wound and bonded to form the outer packaging structure 202, or two or more pieces of the first elastic layer 1 can be butt-bonded to form the outer packaging structure 202. Taking the use of two pieces of the first elastic layer 1 as an example, when surrounding and sealing the inner packaging structure 201, the two pieces of the first elastic layer 1 can be butt-sealed with each other without having a bonding area with the inner packaging structure 201; or, at least one edge of the butt-sealed two pieces of the first elastic layer 1 can be used to cover and bond a portion of the second elastic layer 2, so that the inner and outer packaging structures 201 have a relatively fixed positional relationship, which does not affect the overall packaging barrier effect and facilitates the identification of the front and back of the device or other features.

[0058] Step 4: Inject liquid metal into the remaining space between the inner packaging structure 201 and the outer packaging structure 202 through the liquid metal inlet 6 reserved on the first elastic layer 1 to form an intermediate structure; seal the liquid metal inlet 6.

[0059] Liquid metal injection can be achieved through methods such as pressurized injection or vacuum filling. Taking vacuum filling as an example, it can be further divided into single-port vacuum filling or multi-port vacuum filling. Multi-port vacuum filling is similar to conventional vacuum infusion technology, where a vacuum is created at a pre-reserved evacuation port, and a container holding the liquid metal is connected to the liquid metal inlet. As the pressure in the receiving cavity decreases, the liquid metal enters from the outside and fills the cavity. However, this method results in numerous openings on the first elastic layer 1, making subsequent sealing cumbersome. Therefore, single-port vacuum filling is preferred, specifically including the following steps:

[0060] S4.1: Cover the liquid metal inlet 6 on the first elastic layer 1 with liquid metal, and then place the entire outer packaging structure 202 into a sealed container; preferably, the liquid metal is placed in an open container, the bottom of which has a through hole, and the through hole is aligned with the liquid metal inlet 6 to form a liquid metal flow channel;

[0061] S4.2: Evacuate the sealed container to remove air from the sealed container and the containing cavity;

[0062] S4.3: Break the vacuum in the sealed container; the liquid metal fills the remaining space between the inner packaging structure 201 and the outer packaging structure 202 using the internal and external pressure difference;

[0063] S4.4: Remove the sealed container and seal the liquid metal inlet 6.

[0064] The encapsulation obtained by this invention, under a tensile condition of 5-20%, has an oxygen permeability of 2.5 × 10⁻⁶. - 6 cc / day / cm 2 The preferred value is 2.5×10. -7 cc / day / cm 2 Below, 2×10 is preferred. -7 cc / day / cm 2 Below; water vapor transmission rate is 4.0 × 10⁻⁶ -7 cc / day / cm 2 The preferred size is 3.0×10. -7 cc / day / cm 2 the following.

[0065] Example 1

[0066] The package in this embodiment includes the following structural components:

[0067] Inner encapsulation structure 201: formed by a second elastic layer surrounding and sealing the object to be encapsulated; wherein the second elastic layer is a PDMS (model: Sylgard 184, Dow Chemical Company) inner layer with a thickness of 1 mm;

[0068] Outer packaging structure 202: formed by a first elastic layer surrounding and sealing the inner packaging structure 201; and a glass bead array is bonded to the surface of the first elastic layer facing the second elastic layer; wherein, the first elastic layer is a PDMS outer layer with a thickness of 0.3 mm; the glass beads have a diameter of 0.1 ± 0.01 mm and a spacing of 0.1 ± 0.01 mm;

[0069] Intermediate structure: formed by filling the remaining space between the inner packaging structure 201 and the outer packaging structure 202 with a liquid metal layer; the liquid metal is a eutectic gallium indium alloy (EGaIn) (Shenyang Jiabei Trading Co., Ltd.), with a unit area usage of 0.08 g / cm³. 2 .

[0070] The packaging method for manufacturing package 200 specifically includes the following steps:

[0071] Step 1: Adhere glass beads to one surface of the first elastic layer 1, including:

[0072] S1.1: Apply heat release tape (Linyi Haisi Materials Technology Co., Ltd.) to the bottom of the screen, which has square holes with a side length of 0.15mm; pour glass beads from above the screen, let them pass through the screen and remain on the heat release tape, forming an array pattern;

[0073] S1.2: Apply uncured PDMS adhesive (MS-21-1, Shanghai Mingsheng Rubber Factory) to one surface of the first elastic layer 1, and attach the side of the heat-release tape with the support 4 to the surface of the first elastic layer 1 with adhesive; heat and cure the adhesive, and release the support 4 from the heat-release tape, so that the support 4 adheres to the surface of the first elastic layer 1; the adhesive curing and heat release process specifically includes:

[0074] S1.2.1 Curing adhesive: Curing in an 80℃ oven for 60 minutes;

[0075] S1.2.2 Heat release: Heat to 100℃ to release glass beads from the heat release tape;

[0076] Step 2: Surround and seal the object to be packaged with the second elastic layer 2 to form an inner packaging structure 201;

[0077] Step 3: Surround and seal the inner encapsulation structure 201 with the first elastic layer 1 to form the outer encapsulation structure 202; and make the surface of the first elastic layer 1 with glass beads face the second elastic layer 2;

[0078] Step 4: Liquid metal is injected into the remaining space between the inner packaging structure 201 and the outer packaging structure 202 through the liquid metal inlet 6 reserved on the first elastic layer 1 to form an intermediate structure. The amount of liquid metal used per unit area is 0.08 g / cm³. 2The liquid metal inlet 6 is sealed to obtain the encapsulation body 200.

[0079] The liquid metal is filled using a single-port vacuum filling method, which specifically includes the following steps:

[0080] S4.1: Liquid metal is placed in an open container, the bottom of which has a through hole, which is aligned with the liquid metal inlet 6 and sealed to form a liquid metal flow channel; the outer packaging structure 202 and the open container are placed together in a sealed container;

[0081] S4.2: Evacuate the sealed container to remove air from the sealed container and the containing cavity;

[0082] S4.3: Break the vacuum in the sealed container; the liquid metal fills the remaining space between the inner packaging structure 201 and the outer packaging structure 202 along the liquid metal flow channel using the pressure difference between the inside and outside;

[0083] S4.4: Remove the sealed container and seal the liquid metal inlet 6.

[0084] Example 2

[0085] The main difference between this embodiment and Embodiment 1 is that the amount of liquid metal per unit area of ​​the package is different, resulting in a greater average thickness of the liquid metal layer in Embodiment 2 than in Embodiment 1. Specifically, the package of Embodiment 2 includes the following structural components:

[0086] Inner packaging structure 201: formed by a second elastic layer 2 surrounding and sealing the object to be packaged; wherein, the second elastic layer 2 is a PDMS inner layer with a thickness of 1 mm;

[0087] Outer encapsulation structure 202: formed by a first elastic layer 1 surrounding and sealing the inner encapsulation structure 201; and a glass bead array is bonded to the surface of the first elastic layer 1 facing the second elastic layer 2; wherein, the first elastic layer 1 is a PDMS outer layer with a thickness of 0.3 mm; the glass beads have a diameter of 0.1 ± 0.01 mm and a spacing of 0.1 ± 0.01 mm.

[0088] Intermediate structure: formed by filling the remaining space between the inner packaging structure 201 and the outer packaging structure 202 with a liquid metal layer; the liquid metal is a eutectic gallium indium alloy (EGaIn), with a unit area content of 0.2 g / cm³. 2 .

[0089] Correspondingly, the packaging method for manufacturing package 200 is similar, the only difference being the amount of liquid metal used.

[0090] Example 3

[0091] The main difference between this embodiment and embodiment 2 is that the diameter of the glass beads serving as the support 4 is different, meaning that the effective support density of embodiment 3 is greater than that of embodiment 2. Specifically, the encapsulation body 200 of embodiment 3 includes the following structural components:

[0092] Inner packaging structure 201: formed by a second elastic layer 2 surrounding and sealing the object to be packaged; wherein, the second elastic layer 2 is a PDMS inner layer with a thickness of 1 mm;

[0093] Outer encapsulation structure 202: formed by a first elastic layer 1 surrounding and sealing the inner encapsulation structure 201; and a glass bead array is bonded to the surface of the first elastic layer 1 facing the second elastic layer 2; wherein, the first elastic layer is a PDMS outer layer with a thickness of 0.3 mm; the glass beads have a diameter of 0.2 ± 0.01 mm and a spacing of 0.1 ± 0.01 mm;

[0094] Intermediate structure: formed by filling the remaining space between the inner packaging structure 201 and the outer packaging structure 202 with a liquid metal layer 3; the liquid metal is a eutectic gallium indium alloy (EGaIn), with a unit area content of 0.2 g / cm³. 2 .

[0095] Correspondingly, the packaging method for manufacturing package 200 is similar, except that, based on the glass bead diameter of 0.2±0.01mm, the sieve in step S1.1 has square holes with a side length of 0.3mm.

[0096] Example 4

[0097] The main difference between this embodiment and Embodiment 1 is that the dimensions of each layer of the package are different. Specifically, the package 200 of Embodiment 4 includes the following structural components:

[0098] Inner packaging structure 201: formed by a second elastic layer 2 surrounding and sealing the object to be packaged; wherein, the second elastic layer 2 is a PDMS inner layer with a thickness of 2mm;

[0099] Outer packaging structure 202: formed by a first elastic layer 1 surrounding and sealing the inner packaging structure 201; and a glass bead array is bonded to the surface of the first elastic layer 1 facing the second elastic layer 2; wherein, the first elastic layer 1 is a PDMS outer layer with a thickness of 1 mm; the glass beads have a diameter of 0.5 ± 0.02 mm and a spacing of 3 ± 0.1 mm;

[0100] Intermediate structure: formed by filling the remaining space between the inner packaging structure 201 and the outer packaging structure 202 with a liquid metal layer 3; the liquid metal is a eutectic gallium indium alloy (EGaIn), with a unit area content of 0.5 g / cm³. 2 .

[0101] Correspondingly, the packaging method for manufacturing package 200 is similar, the main difference being that, based on the glass bead diameter of 0.5±0.02mm, the screen in step S1.1 can be selected with a square hole with a side length of 0.6-0.8mm.

[0102] Comparative Example 1

[0103] The main difference between the package in this comparative document and those in Examples 2 or 3 is that it does not use a support structure. The package in Comparative Example 1 comprises the following structural components:

[0104] Inner packaging structure: formed by a second elastic layer surrounding and sealing the object to be packaged; wherein, the second elastic layer is a PDMS inner layer with a thickness of 1mm;

[0105] Outer packaging structure: formed by a first elastic layer surrounding and sealing the inner packaging structure; wherein the first elastic layer is a PDMS outer layer with a thickness of 0.3 mm;

[0106] Intermediate structure: formed by filling the remaining space between the inner and outer packaging structures with a liquid metal layer; the liquid metal is a eutectic gallium indium alloy (EGaIn), with a content of 0.2 g / cm³ per unit area. 2 .

[0107] The packaging method for manufacturing packaged components specifically includes the following steps:

[0108] Step 1: Surround and seal the object to be packaged with a second elastic layer to form an inner packaging structure;

[0109] Step 2: Surround and seal the inner encapsulation structure with the first elastic layer to form the outer encapsulation structure;

[0110] Step 3: Liquid metal is injected into the space between the inner and outer packaging structures through the liquid metal inlet pre-reserved on the first elastic layer to form an intermediate structure. The amount of liquid metal used per unit area is 0.2 g / cm³. 2 The liquid metal inlet is sealed to obtain the encapsulated body.

[0111] Comparative Example 2

[0112] The main difference between this comparative example and Examples 1-3 is that it does not use a liquid metal layer, that is, it only has two elastic layers, and its package specifically includes the following structure:

[0113] Inner packaging structure: formed by a second elastic layer surrounding and sealing the object to be packaged; wherein, the second elastic layer is a PDMS inner layer with a thickness of 1mm;

[0114] Outer packaging structure: formed by a first elastic layer surrounding and sealing the inner packaging structure; wherein the first elastic layer is a PDMS outer layer with a thickness of 0.3 mm.

[0115] The package in this comparative example can be prepared either by first forming an inner package structure and then forming an outer package structure around the inner package structure, or by first joining the first elastic layer and the second elastic layer to obtain two elastic composite layers, and then surrounding and sealing the object to be packaged.

[0116] Performance Tests and Results

[0117] Water vapor and oxygen permeability tests were conducted on the composite layered structures of the encapsulations in Examples 1-4 and Comparative Examples 1-2 to compare the barrier performance of each encapsulation under unstretched and 20% stretching conditions. The stretching was performed simultaneously on the first elastic layer 1 and the second elastic layer 2 in the same plane.

[0118] A water vapor transmission rate (WVTR) permeation analyzer (AQUATRAN 3, AMETEK MOCON) was used to measure the water transmission rate. The measurement temperature was set to 25°C. Samples from Examples 1-4 and Comparative Examples 1-2 were placed between two chambers with different water vapor partial pressures; the relative humidity of one chamber was set to 90%, and the relative humidity of the other chamber was set to 0%. The measurement was performed at a depth of 2.3 cm⁻¹. 2 The water vapor permeability through the sample over its area was measured.

[0119] An oxygen permeability (OTR) permeation analyzer (OX-TRAN 2 / 22H, AMETEK MOCON) was used to measure oxygen permeability. The test temperature was set to 25°C. One side of the sample contained oxygen, and the other side contained nitrogen at the same pressure; the partial pressure difference of oxygen on both sides of the sample was set to one standard atmosphere. The sample test surface area was 28.3 cm². 2 .

[0120] Breathability T (cc / day / cm) 2 ), defined by the following equation:

[0121] T = J / s

[0122] In the formula, J is the gas flux through the sample per unit time, in cc / day; s is the sample surface area, in cm². 2 .

[0123] The material composition and test results of Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0124] Table 1. Material composition and test results of Examples 1-4 and Comparative Examples 1-2. Based on the test results in Table 1, the oxygen permeability of samples from Examples 1-4 under 20% tensile condition...

[0125]

[0126] The rate is 2.5×10 -7 cc / day / cm 2 Below, and with a water vapor transmission rate of 4.0 × 10⁻⁶ -7 cc / day / cm 2 As can be seen below, the composite structure and its encapsulation of the present invention not only have excellent gas and water barrier properties in a static environment, but also maintain their gas and water barrier properties well under 20% stretching conditions. It can provide flexible, stretchable and excellent sealing performance for device encapsulation protection, making it an ideal multifunctional encapsulation material.

[0127] Specifically, Examples 1 and 2 have the same elastic layer, but the amount of liquid metal per unit area is different. Example 2, which has a larger amount of liquid metal, shows a liquid metal layer with a larger average thickness. Its oxygen permeability and water vapor permeability under static and 20% tensile conditions are lower than those of Example 1, indicating that the barrier performance of the sample is mainly reflected through the liquid metal layer.

[0128] The elastic layer and liquid metal usage in Examples 2 and 3 are basically the same, and the oxygen permeability and water vapor permeability under static conditions are also basically the same; however, the glass beads in Example 3 have a relatively larger diameter, and with the same spacing, the effective support height is greater. After 20% stretching, Example 3 shows better barrier performance retention. It can be seen that the size change of the support has a significant impact on the barrier performance under stretching conditions.

[0129] Compared with Examples 1-3, Example 4 has the largest amount of liquid metal per unit area and also uses glass beads with a relatively larger size that is adapted to the thickness of the liquid metal. Although the spacing between the glass beads is relatively large, the two positive factors mentioned above can better meet the extrusion deformation caused by 20% stretching. Therefore, its oxygen permeability and water vapor permeability are better under both static and 20% stretching conditions.

[0130] Compared to soft PDMS and flowable liquid metals, glass beads can be considered rigid materials, providing strong support between two PDMS layers to resist deformation and the resulting contact pressure. The stress process can be referenced... Figure 2 As shown.

[0131] In contrast, Comparative Example 1, which does not have a support structure, exhibits similar performance in terms of oxygen permeability and water vapor permeability under static conditions to samples with similar elastic and liquid metal layers. However, its barrier performance decreases significantly under 20% stretching, limiting its applicability to static use and severely restricting its application scenarios. Comparative Example 2, which does not use a liquid metal layer, relies primarily on the elastic layer for its barrier performance, thus failing to meet practical requirements under both static and stretching conditions. Furthermore, the comparison demonstrates that this invention, with its combination of a liquid metal layer and a support structure, effectively achieves a balance between flexibility, stretchability, and high sealing performance, providing a high-performance encapsulation material, broadening its applications, and making a creative contribution to the technological development of the encapsulation field.

[0132] The preferred embodiments of the present invention have been described above to make the spirit of the present invention clearer and easier to understand, and are not intended to limit the present invention. All modifications, substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope summarized by the appended claims.

Claims

1. A flexible, stretchable layered composite structure comprising liquid metal, characterized in that, It comprises a first elastic layer, a liquid metal layer, and a second elastic layer in sequence; a plurality of low-permeability material supports in an array pattern are bonded to the surface of the first elastic layer facing the second elastic layer, and / or a plurality of low-permeability material supports in an array pattern are bonded to the surface of the second elastic layer facing the first elastic layer; the liquid metal layer fills the remaining space between the first elastic layer and the second elastic layer. The first elastic layer and the second elastic layer include at least one of the following: a natural rubber layer, a synthetic rubber layer, an ionogel layer, and a hydrogel layer; The support is spherical in shape, and the low-permeability material is selected from at least one of metals, inorganic non-metals, or composite materials thereof.

2. The flexible and stretchable layered composite structure as described in claim 1, characterized in that, The liquid metal in the liquid metal layer is selected from at least one of gallium-based liquid metal, indium-based liquid metal, and bismuth-based liquid metal.

3. The flexible and stretchable layered composite structure as described in claim 2, characterized in that, The thickness of the first elastic layer is 0.001-10mm, and the thickness of the second elastic layer is 0.001-10mm.

4. The flexible and stretchable layered composite structure according to any one of claims 1-3, characterized in that, The diameter D of the sphere is 0.01-1mm, and the distance H between adjacent spheres satisfies 0≤H≤10D.

5. The flexible and stretchable layered composite structure as described in claim 4, characterized in that, The support is a glass bead.

6. A package having the flexible, stretchable layered composite structure according to any one of claims 1-5, characterized in that, include: The inner encapsulation structure is formed by a second elastic layer surrounding and sealing the object to be encapsulated; The outer encapsulation structure is formed by a first elastic layer surrounding and sealing the inner encapsulation structure; and a plurality of low-permeability material supports in an array pattern are bonded to the surface of the first elastic layer facing the second elastic layer, and / or a plurality of low-permeability material supports in an array pattern are bonded to the surface of the second elastic layer facing the first elastic layer. The intermediate structure is formed by filling the remaining space between the inner and outer packaging structures with a liquid metal layer. The first elastic layer and the second elastic layer include at least one of the following: natural rubber layer, synthetic rubber layer, ionogel layer, and hydrogel layer. The low-permeability material is selected from at least one of metals, inorganic non-metals, or composites thereof.

7. The package as claimed in claim 6, characterized in that, Under a tensile stress of 5-20%, the oxygen permeability of the encapsulation is 2.5 × 10⁻⁶. -6 cc / day / cm 2 Below, the water vapor transmission rate is 4.0 × 10⁻⁶. -7 cc / day / cm 2 the following.

8. A packaging method for manufacturing the package according to claim 6 or 7, characterized in that, Includes the following steps: Step 1: Adhere a low-permeability material support to one surface of the first elastic layer and / or one surface of the second elastic layer; Step 2: Surround and seal the object to be packaged with a second elastic layer to form an inner packaging structure; Step 3: Surround and seal the inner encapsulation structure with the first elastic layer to form the outer encapsulation structure; and make the surface of the first elastic layer with the low-permeability material support face the second elastic layer, and / or the surface of the second elastic layer with the low-permeability material support face the first elastic layer. Step 4: Inject liquid metal into the remaining space between the inner and outer packaging structures through the liquid metal inlet reserved on the first elastic layer to form an intermediate structure; seal the liquid metal inlet.

9. The packaging method as described in claim 8, characterized in that, Step one, the method of bonding the support to the first elastic layer and / or the second elastic layer, includes the following steps: S1.1: Attach heat release tape to the bottom of the screen, pour several low-permeability material supports down from above the screen, let them pass through the screen and remain on the heat release tape, forming an array pattern; S1.2: Apply uncured adhesive to one surface of the first elastic layer and / or one surface of the second elastic layer, and attach the side of the heat release tape with the support to the adhesive surface of the first elastic layer and / or the second elastic layer. The adhesive is heated and cured, and the support is released from the heat-release tape, so that the low-permeability material support is bonded to the surface of the first elastic layer and / or the second elastic layer.

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