A liquid metal electronic skin shaped on demand and a preparation method and application thereof

Abstract

The application discloses a liquid metal electronic skin shaped on demand and a preparation method and application thereof, and belongs to the technical field of flexible electronics and wearable sensing. The electronic skin comprises a gallium-indium series liquid metal functional unit and a dynamic shaping connecting layer. The liquid metal functional unit comprises a gallium-indium series liquid metal functional body and a polyvinyl alcohol stable packaging layer coated outside the functional body, which is used for limiting the migration of the liquid metal and keeping the continuity of the conductive channel. The dynamic shaping connecting layer is composed of a borate dynamic cross-linking polyvinyl alcohol network, which is used for connecting the liquid metal functional unit and realizing the adjustment of the device morphology. The application realizes the shaping on demand after preparation through the functional separation of the stable packaging network and the dynamic shaping network, and the device morphology can be adjusted according to the human body curve and the detection requirement. The preparation method is simple, and the obtained electronic skin can be used for physiological signal collection such as electroencephalogram, electrocardiogram and electromyogram and human body deformation detection.

Description

Technical Field

[0001] This invention belongs to the fields of flexible electronics, bioelectronics, and wearable sensing technology. Specifically, it relates to a liquid metal electronic skin that uses a differentiated cross-linked polyvinyl alcohol network to encapsulate liquid metal functional channels in layers, and can be shaped as needed according to human body parts and detection tasks after preparation. It also relates to the preparation method of the electronic skin and its application in human bioelectric signal acquisition and human deformation sensing. Background Technology

[0002] Electronic skin is a type of flexible electronic device that can simulate the sensory functions of human skin. It forms an interface with the human body surface through flexible conductive circuits, electrode units, or sensitive structures. It can be used to acquire bioelectrical signals such as electroencephalograms (EEG), electrocardiograms (ECG), electromyograms (EMG), and electrooculograms (EOG), as well as to sense human movement, pressure, and deformation. With the development of personalized health monitoring and human-computer interaction, electronic skin not only needs to be soft, stretchable, and have good conformability, but also needs to be able to adjust its shape according to different body parts and detection tasks to adapt to different curvatures and wearing requirements.

[0003] Existing flexible electronic skin typically uses elastomer films, pre-fabricated microchannels, or fixed-shape hydrogels as device substrates. For example, CN206228336U discloses an electronic skin based on liquid metal flexible circuitry, achieving flexible sensing by integrating liquid metal conductive structures within a flexible substrate; CN112165766A discloses a liquid metal flexible electronic device, achieving flexible conductivity by constructing liquid metal microchannels within an elastic polymer. However, the conductive structures and device shapes in these solutions rely on pre-designed molds or processing techniques. The devices primarily achieve fit through elastic bending and stretching, and typically return to their original shape after the external force is removed, making it difficult to personalize them for different parts of the human body during use.

[0004] Gallium-based liquid metals possess high electrical conductivity, low elastic modulus, and excellent deformation adaptability, making them widely used in flexible electrodes and electronic skin. For example, CN119757490A discloses a high-density, stretchable liquid metal-based bioelectrode for acquiring human physiological signals; CN116566237A discloses a polyvinyl alcohol / liquid metal hydrogel flexible electrode, achieving flexible conductivity by introducing liquid metal into a PVA hydrogel network. However, existing liquid metal devices are typically encapsulated using a fixed elastic substrate or by directly compositing the liquid metal with the hydrogel. The former limits the device's subsequent morphological adjustment capabilities, while the latter is prone to liquid metal migration, leakage, and fusion of adjacent conductive areas under external forces.

[0005] Polyvinyl alcohol (PVA) hydrogels possess excellent flexibility, biocompatibility, and mechanical tunability. Borates such as borax can form dynamic cross-linked networks with PVA, enabling the material to exhibit certain morphology adjustment capabilities. For example, CN106823019A discloses a dynamic hydrogel material based on a borax-crosslinked PVA network. However, such dynamic networks are mainly used to improve the material's processability and resilience. If directly applied to liquid metal electronic skin, it would be difficult to simultaneously meet the requirements of stable liquid metal encapsulation, multi-channel electrical isolation, and long-term signal acquisition.

[0006] Therefore, current technology lacks a liquid metal electronic skin that can balance stable packaging with on-demand shaping capabilities. Such devices need to maintain the independent stability of the liquid metal channels, avoid migration leakage and signal crosstalk, while enabling multiple functional units to achieve overall shape adjustment through a dynamic connection structure. This allows for on-demand shaping according to the curvature of the human body and the detection task, and achieves stable bioelectrical signal acquisition or human state perception. Summary of the Invention

[0007] To address the problem that existing liquid metal electronic skins struggle to balance stable liquid metal encapsulation capabilities with on-demand device shaping capabilities, this invention provides an on-demand shaped liquid metal electronic skin, its preparation method, and its applications.

[0008] This invention employs a dual-network functional separation design to construct a liquid metal electronic skin composed of a stable anchoring network and a dynamic shaping network. Specifically, a polyvinyl alcohol (PVA) stable encapsulation layer formed by freeze-thaw induced physical cross-linking independently confines the liquid metal functional units, ensuring continuous conductivity even under bending, stretching, or shape adjustment, and reducing the risks of liquid metal migration, leakage, and channel fusion. Simultaneously, a dynamic shaping connection layer is formed by dynamically cross-linking PVA with borate, creating mechanical interconnections between one or more liquid metal functional units. This allows for on-demand shaping and human body surface adaptation after the electronic skin is fabricated, while maintaining the integrity of the liquid metal channels and multi-channel electrical isolation.

[0009] To achieve the above objectives, the present invention adopts the following technical solution.

[0010] An on-demand shaped liquid metal electronic skin includes at least one liquid metal functional unit and a dynamically shaped connection layer connected to the liquid metal functional unit.

[0011] The liquid metal functional unit includes a liquid metal functional body and a polyvinyl alcohol stabilizing encapsulation layer covering the outside of the liquid metal functional body.

[0012] The polyvinyl alcohol stable encapsulation layer is formed through freeze-thaw induced physical crosslinking. The freeze-thaw induced physical crosslinking process causes the polyvinyl alcohol molecular chains to form stable microcrystalline crosslinked regions, thereby constructing a polymer network with certain mechanical support and flexibility. This network is used to limit the spatial migration boundary of the liquid metal functional body, maintain the continuity of the liquid metal channel, and improve the structural stability of the liquid metal functional body during repeated morphological adjustments.

[0013] The dynamic shaping connection layer is disposed between one or more liquid metal functional units and / or on the outside of the liquid metal functional units. The dynamic shaping connection layer is composed of a reversible dynamic cross-linking network formed by borate and polyvinyl alcohol, which is used to connect different liquid metal functional units and endow the electronic skin with the ability to change its overall shape and local curvature under the action of external force.

[0014] In this invention, the stable packaging network and the dynamic shaping network respectively undertake the functions of liquid metal confinement and device shape adjustment. By separating the functions, the problem of decreased conductivity stability caused by a single dynamic network simultaneously undertaking liquid metal packaging and shape reconstruction is avoided.

[0015] Furthermore, the on-demand shaping refers to the fact that after the liquid metal functional body is formed and polyvinyl alcohol is stably encapsulated, the electronic skin can still change the overall shape, local curvature, bending angle and relative spatial position between different functional units by manual or mechanical external force according to the user's body contour, wearing position or testing task requirements, and maintain the target shape and predetermined electrical performance during the testing process.

[0016] Furthermore, the target shape includes, but is not limited to, planar shapes, arc-shaped structures, ring-shaped structures, wave-shaped structures, bifurcated structures, and three-dimensional structures that match the local curved surfaces of the human body.

[0017] Furthermore, the polyvinyl alcohol mass fraction of the polyvinyl alcohol stabilizing encapsulation layer is 8% to 20%, preferably 10% to 15%; the thickness of the stabilizing encapsulation layer is 0.3 to 3.0 mm.

[0018] Furthermore, the polyvinyl alcohol content in the dynamic shaping bonding layer is 6%–18%, the borate content is 0.5%–4.0%, and the thickness of the dynamic shaping bonding layer is 0.5–5.0 mm.

[0019] Furthermore, moisturizing components such as glycerin, sorbitol, and polyethylene glycol can be added to the dynamic shaping connection layer to reduce moisture evaporation and improve softness and shape retention during long-term wear.

[0020] Furthermore, both the polyvinyl alcohol stabilizing encapsulation layer and the dynamic shaping connecting layer use polyvinyl alcohol as the main polymer. At the interface, the two form a homologous polymer connection interface through polymer segment interdiffusion, hydrogen bonding, and dynamic cross-linking, which improves the bonding stability between the two layers and reduces the risk of delamination between dissimilar materials.

[0021] Furthermore, the liquid metal functional body is a gallium-based liquid metal, including gallium, gallium-indium alloy, eutectic gallium-indium alloy, gallium-indium-tin alloy, or other metal alloys that remain in a liquid or flowable state within the operating temperature range of the electronic skin; preferably, eutectic gallium-indium alloy is used.

[0022] Furthermore, the liquid metal functional body forms conductive lines, electrode structures, or deformation sensing structures according to the functional requirements of electronic skin, including linear channels, serpentine channels, wavy channels, grid structures, ring structures, bifurcated structures, and combinations of the above structures.

[0023] Furthermore, when the electronic skin includes two or more liquid metal functional units, each liquid metal functional unit is independently covered by a corresponding polyvinyl alcohol stabilizing encapsulation layer, and adjacent liquid metal functional units are spatially isolated through the stabilizing encapsulation layer; the dynamic shaping connection layer connects each liquid metal functional unit, so that multiple functional units form a continuous whole mechanically, while maintaining electrical independence between each liquid metal channel.

[0024] Furthermore, the liquid metal functional unit includes a bioelectricity acquisition unit, which includes a skin contact area electrically connected to the liquid metal functional body for forming an electrical signal transmission interface with human skin.

[0025] Furthermore, the skin contact area includes one or more of the following: ion-conductive polyvinyl alcohol gel, conductive polymer layer, carbon-based conductive layer, metal contact layer, or microstructure contact layer, for collecting one or more physiological electrical signals from electroencephalography (EEG), electrocardiography (ECG), electromyography (EMG), and electrooculography (EOG).

[0026] Furthermore, the liquid metal functional unit includes a human body deformation sensing unit, which adopts a serpentine, wave-shaped, or grid-like liquid metal structure. During human movement, bending, stretching, compression, or torsion, it generates changes in resistance, capacitance, or impedance to detect human movement, breathing, swallowing, or local surface deformation.

[0027] The present invention also provides a method for preparing the above-mentioned on-demand shaped liquid metal electronic skin, comprising the following steps:

[0028] (1) Prepare a polyvinyl alcohol precursor solution and form a stable polyvinyl alcohol encapsulation layer with a stable network structure by freeze-thaw cycle treatment;

[0029] (2) A liquid metal functional body is formed on the polyvinyl alcohol stable encapsulation layer, so that the liquid metal forms a predetermined conductive pattern or sensing structure;

[0030] (3) The liquid metal functional body is covered and encapsulated using polyvinyl alcohol precursor liquid, and the upper and lower polyvinyl alcohol layers are combined to form an independent liquid metal functional unit through freeze-thaw treatment.

[0031] (4) Arrange one or more liquid metal functional units according to the target layout, place polyvinyl alcohol precursor liquid between or on the outside of the functional units, and add borate to form a dynamic shaping connection layer;

[0032] (5) Apply external force to the electronic skin to shape it according to the target human body part or detection task, so that it forms the target spatial shape and establish the electrical detection baseline under the corresponding shape.

[0033] Furthermore, in step (2), the liquid metal functional body is formed by direct writing printing, template scraping, injection filling, microfluidic infusion, transfer printing or manual laying.

[0034] Furthermore, in step (4), the dynamic shaping bonding layer is formed by casting, coating, local spot coating, bonding or impregnation.

[0035] The present invention also provides the application of the above-mentioned on-demand shaped liquid metal electronic skin in human physiological signal acquisition and human state perception.

[0036] The applications include, but are not limited to:

[0037] (1) Used for collecting human bioelectric signals such as electroencephalogram (EEG), electrocardiogram (ECG), electromyogram (EMG), and electrooculogram (EOG);

[0038] (2) Used for detecting human movements, joint movements, respiratory changes, swallowing movements, and skin surface deformation;

[0039] (3) Used to construct personalized wearable electronic skin that meets the needs of different body parts and individuals.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) Achieve on-demand shaping after preparation.

[0042] This invention endows electronic skin with shape adjustment capabilities through a dynamic shaping connection layer, so that the device is no longer limited to the fixed contour determined in the preparation stage, but can form a target shape according to different human curvatures and detection tasks, thereby improving the adaptability of electronic skin to different individuals and different application scenarios.

[0043] (2) Achieve functional separation between stable packaging and dynamic shaping.

[0044] This invention employs a collaborative design of a stable anchoring network and a dynamic shaping network. The stable encapsulation network is responsible for confining the liquid metal functional body and maintaining its conductivity, while the dynamic shaping network is responsible for connecting functional units and adjusting their shape, thus solving the problem of balancing stability and plasticity in traditional single-network systems.

[0045] (3) Achieve synergy between mechanical continuity and electrical isolation.

[0046] Multiple liquid metal functional units are connected by a dynamic shaping layer to form a mechanically continuous whole, while each liquid metal channel is still isolated by an independent and stable encapsulation layer, thereby reducing liquid metal migration, channel fusion and crosstalk of multi-channel signals during the shaping process.

[0047] (4) Improve the individualized adaptation capability of human electronic skin.

[0048] By adjusting the structure of the liquid metal functional body and the skin contact interface, this invention can adapt to the curved surface features of different parts of the human body, and realize personalized physiological signal acquisition and human state perception. Attached Figure Description

[0049] Figure 1 This is a schematic diagram illustrating the structure and preparation process of the on-demand shaped liquid metal electronic skin of the present invention;

[0050] Figure 2 This is a photograph of the actual product of the on-demand shaped liquid metal electronic skin of the present invention;

[0051] Figure 3 This is a scanning electron microscope image of the polyvinyl alcohol network structure in the on-demand shaped liquid metal electronic skin of the present invention;

[0052] Figure 4 This is a schematic diagram of the conductivity test of the on-demand moldable liquid metal electronic skin under stretched conditions according to the present invention.

[0053] Figure 5 The present invention relates to on-demand shaped liquid metal electronic skin for the acquisition of physiological electrical signals.

[0054] Reference numerals in the figures: 1-GaIn-based liquid metal functional body; 2-Polyvinyl alcohol stable encapsulation layer; 3-Dynamically shaped connection layer; 4-Liquid metal functional unit; 5-Signal output terminal. Detailed Implementation

[0055] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0056] The polyvinyl alcohol stable encapsulation layer in this invention refers to a stable polyvinyl alcohol network that directly encapsulates the liquid metal functional body and is mainly used to restrict the migration of liquid metal and maintain the continuity of the liquid metal channel; the polyvinyl alcohol dynamic shaping and connecting layer refers to a borate dynamic cross-linked polyvinyl alcohol network that is disposed outside the liquid metal functional unit or between multiple functional units and is mainly used to realize the mechanical connection of functional units and the adjustment of device shape.

[0057] The polyvinyl alcohol stabilizing encapsulation layer and the polyvinyl alcohol dynamic shaping connection layer are functionally independent. The stabilizing encapsulation layer is used to maintain the structural integrity of the liquid metal functional body, and the dynamic shaping connection layer is used to realize the shape adjustment of the electronic skin. Both use polyvinyl alcohol as the main polymer and form a continuous polymer connection structure at the interface.

[0058] Specific Implementation Method 1: A liquid metal electronic skin that can be shaped on demand includes multiple liquid metal functional units and a polyvinyl alcohol (PVA) dynamic shaping connection layer connecting the functional units. Each liquid metal functional unit includes a liquid metal functional body and a PVA stable encapsulation layer covering the outside of the liquid metal functional body. The stable encapsulation layer continuously covers the upper and lower surfaces and sidewalls of the liquid metal functional body, giving the liquid metal channels independent encapsulation boundaries. Multiple liquid metal functional units are arranged at a preset spacing, with isolation areas formed by the stable encapsulation layer between the functional units; the PVA dynamic shaping connection layer covers the outside of the functional units and fills the connection areas between adjacent functional units, making the multiple liquid metal functional units form a mechanically continuous whole. Under external force, the electronic skin can bend, fold, and undergo local shape adjustments, while the liquid metal functional body still maintains an independent conductive state.

[0059] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the polyvinyl alcohol (PVA) stable encapsulation layer is formed using a freeze-thaw induced physical crosslinking method. Specifically, PVA is dissolved in deionized water to form a PVA precursor solution. After film formation, a freeze-thaw cycle is performed to allow the PVA molecular chains to form physically crosslinked microcrystalline regions, thereby obtaining a PVA stable encapsulation network with stable mechanical support capabilities. The freeze-thaw process includes: freezing at -15 to -25°C for 8 to 16 hours, followed by thawing at 20 to 30°C for 4 to 8 hours, repeated 2 to 5 times. The PVA stable encapsulation layer formed in this way can restrict the migration of liquid metal functional groups while maintaining flexibility.

[0060] Specific Implementation Method Three: This implementation method differs from Specific Implementation Methods One or Two in that the polyvinyl alcohol dynamic shaping connecting layer forms a dynamic cross-linking network between borate and polyvinyl alcohol. Borate and the hydroxyl groups on the polyvinyl alcohol molecular chain form a reversible dynamic cross-linking structure. Under external force, the dynamic cross-linking points dissociate and recombine, allowing the connecting region to undergo morphological adjustment. After the external force is removed, the dynamic cross-linking network is re-established, enabling the electronic skin to maintain its adjusted target shape. Through the synergistic effect of the stable encapsulation network and the dynamic shaping network, the electronic skin simultaneously possesses the stable confinement capability of liquid metal and the morphological adjustment capability.

[0061] Example 1: Polyvinyl alcohol with a degree of polymerization of about 1700 and a degree of alcoholysis of not less than 98% was selected as the main material.

[0062] Polyvinyl alcohol (PVA) was added to deionized water and stirred at 95°C for 2 hours to prepare a 12% (w / w) PVA precursor solution. This precursor solution was poured into a mold to form a PVA layer approximately 0.8 mm thick. The layer was then subjected to two freeze-thaw cycles (freezing at -20°C for 12 hours and thawing at 25°C for 6 hours) to obtain a stable PVA encapsulation layer. A liquid metal channel template, approximately 0.8 mm wide and 0.4 mm high, was formed on the surface of the stable encapsulation layer, covered with the PVA precursor solution, and subjected to another freeze-thaw cycle to form a stable encapsulation layer with a closed channel structure. Subsequently, a eutectic gallium-indium alloy, with a gallium to indium mass ratio of 75.5:24.5, was injected into the channel to form a liquid metal functional unit. Each liquid metal channel was 50 mm long and had an initial resistance of 0.16–0.22 Ω. Multiple liquid metal functional units were arranged with a spacing of 3 mm. A 10% (w / w) polyvinyl alcohol precursor solution was added to the outer side of each unit, and a 2% (w / w) borax solution was added to form a dynamic shaping connection layer. Glycerin (12% (w / w)) was added to the dynamic shaping connection layer as a moisturizing component, resulting in an on-demand shaped liquid metal electronic skin with a thickness of approximately 1.5 mm. Cross-sectional observation showed that the liquid metal functional units were stably encapsulated within the polyvinyl alcohol network, and a continuous interface was formed between the dynamic shaping connection layer and the stable encapsulation layer. No liquid metal leakage was observed after 20 bends and kneading cycles, and each liquid metal channel maintained independent conductivity.

[0063] Example 2: The electronic skin prepared in Example 1 was shaped from its initial planar state into arc-shaped, ring-shaped, and bifurcated structures. The radii of curvature for the arc-shaped structures were set to 15 mm, 25 mm, and 40 mm, respectively; the inner diameter of the ring-shaped structure was 28 mm; and the included angle of the bifurcated structure was 55°. The electronic skin maintained its target shape after being shaped by external force. Under environmental conditions of 25°C and 60% relative humidity, the shape retention rates at 10 min, 60 min, and 4 h after shaping were 91.4%, 84.6%, and 76.9%, respectively. After the electronic skin was repeatedly transformed between planar, arc-shaped, and ring-shaped states 30 times, no open circuit or significant leakage occurred in the liquid metal channel, and the resistance change rate did not exceed 6.3%.

[0064] As a control, the electronic skin with only a stable encapsulation layer but no dynamic shaping connection layer showed significant shape recovery after the external force was removed; while the control sample with liquid metal directly encapsulated in a borax-PVA dynamic network showed liquid metal migration during repeated kneading.

[0065] Example 3: Channel isolation test was conducted using an electronic skin with four parallel liquid metal channels.

[0066] A test signal was input to one of the liquid metal channels, and the induced signals generated in adjacent channels were detected to evaluate the electrical coupling between different channels. The results showed that the crosstalk ratio between adjacent channels in the planar state of the electronic skin was less than 3%, and the channels remained electrically independent after arc shaping and multiple mechanical deformations. The control device without an independent stable packaging region exhibited significant signal coupling under the same conditions and produced localized conduction anomalies after mechanical deformation.

[0067] The results show that the stable encapsulation layer can effectively maintain electrical isolation between liquid metal channels, while the dynamic shaping connection layer mainly undertakes the mechanical connection function.

[0068] Example 4: The electronic skin was designed as three independent bioelectrical acquisition units, serving as the recording electrode, reference electrode, and ground electrode, respectively. Each electrode was connected to the signal output terminal through an independent liquid metal channel, and the skin contact area adopted a conductive polyvinyl alcohol gel structure. Based on the curvature of the subject's forehead, the electronic skin was shaped into an arc-shaped strip structure for EEG signal acquisition.

[0069] Test results show that the electronic skin can stably record human EEG signals, with significant signal enhancement in the 8–13 Hz frequency band when the eyes are closed, enabling basic EEG state recognition. The same device can maintain stable signal output even after being shaped with different curvatures, indicating that on-demand shaping can improve the electronic skin's adaptability to different human body surfaces.

Claims

1. A liquid metal electronic skin that can be shaped on demand, characterized in that, It includes at least one liquid metal functional unit and a dynamically shaped connecting layer; The liquid metal functional unit includes a gallium indium-based liquid metal functional body and a stable encapsulation layer covering the exterior of the gallium indium-based liquid metal functional body. The stable encapsulation layer is used to define the spatial position of the gallium indium-based liquid metal functional body, restrict the migration of liquid metal under external force, and maintain the continuity of the liquid metal conductive channel. The dynamic shaping connection layer is disposed on the outside of the liquid metal functional unit and / or between multiple liquid metal functional units, for connecting different liquid metal functional units, and enabling the electronic skin to adjust its shape according to the curvature of the human body, wearing position or detection needs; The stable encapsulation layer and the dynamic shaping connection layer respectively undertake the functions of liquid metal stabilization and confinement and device dynamic shaping, so that the electronic skin maintains the integrity of the gallium indium liquid metal channel and the electrical isolation between multiple channels during the shape adjustment process.

2. The on-demand sculptable liquid metal electronic skin according to claim 1, characterized in that, The stable encapsulation layer is a polyvinyl alcohol stable encapsulation layer, which is composed of a stable cross-linked network formed by polyvinyl alcohol, and is used to improve the encapsulation stability of gallium indium-based liquid metal functional bodies during bending, stretching, compression or repeated shaping processes.

3. The on-demand sculptable liquid metal electronic skin according to claim 2, characterized in that, The polyvinyl alcohol stable encapsulation layer is formed by freeze-thaw induced physical cross-linking, which causes the polyvinyl alcohol molecular chains to form microcrystalline cross-linked regions. The freeze-thaw induced physical crosslinking includes freezing treatment and thawing treatment, wherein the freezing temperature is -15 to -25°C, the freezing time is 8 to 16 hours, the thawing temperature is 20 to 30°C, and the thawing time is 4 to 8 hours.

4. The on-demand sculptable liquid metal electronic skin according to claim 1, characterized in that, The dynamic shaping connection layer is a borate dynamic cross-linked polyvinyl alcohol network; The borate and polyvinyl alcohol form a reversible dynamic cross-linking structure, which allows the dynamic shaping connecting layer to adjust its shape under external force and maintain the adjusted structural shape after the external force is removed.

5. The on-demand sculptable liquid metal electronic skin according to claim 1, characterized in that, Both the stable encapsulation layer and the dynamic shaping connection layer use polyvinyl alcohol as the main polymer, and form a homologous polymer connection interface through polymer segment interdiffusion, hydrogen bonding and dynamic cross-linking.

6. The on-demand sculptable liquid metal electronic skin according to claim 1, characterized in that, The gallium-indium liquid metal functional body is a gallium-indium alloy or a eutectic gallium-indium alloy, preferably a eutectic gallium-indium alloy; The gallium-indium liquid metal functional body forms a conductive line, electrode structure, or sensing structure, wherein the structure includes at least one of a linear channel, a serpentine channel, a wavy channel, a mesh structure, a ring structure, or a bifurcated structure.

7. The on-demand shaped liquid metal electronic skin according to claim 1, characterized in that, Includes two or more liquid metal functional units; Each gallium-indium liquid metal functional unit is independently encapsulated by a corresponding stable encapsulation layer, and an isolation region is formed between adjacent functional units; The dynamic shaping connection layer connects multiple liquid metal functional units, enabling the electronic skin to form a mechanically continuous structure while maintaining the electrical independence between each gallium-indium liquid metal channel.

8. The on-demand shaped liquid metal electronic skin according to claim 1, characterized in that, The liquid metal functional unit includes a bioelectricity acquisition unit and / or a human body deformation sensing unit; The bioelectric acquisition unit is used to acquire electroencephalogram (EEG), electrocardiogram (ECG), electromyogram (EMG), or electrooculogram (EOG) signals. The human body deformation sensing unit is used to detect human movement, breathing, swallowing, or surface deformation.

9. A method for preparing on-demand shaped liquid metal electronic skin as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Step 1: Preparation of stable encapsulation layer: Prepare polyvinyl alcohol precursor solution and form a stable encapsulation layer for coating gallium indium-based liquid metal functional body; Step 2: Fabrication of liquid metal functional units: Gallium-indium liquid metal functional bodies with a predetermined pattern are formed in the stable encapsulation layer, and encapsulation is completed to obtain independent liquid metal functional units; Step 3, Construction of Dynamic Shaping Layer: Arrange one or more liquid metal functional units and form a borate dynamic cross-linked polyvinyl alcohol connecting layer on their outer side and / or connecting area; Step 4: Shape Adjustment: Apply external force to shape the resulting electronic skin according to the wearer's needs.

10. The preparation method according to claim 9, characterized in that, The gallium-indium liquid metal functional body is formed by direct writing printing, injection filling, template transfer, microchannel infusion or manual laying. The dynamic shaping connecting layer is formed by casting, coating, impregnation, bonding, or partial filling. The resulting on-demand moldable liquid metal electronic skin is used as a flexible electrode device for collecting human physiological signals, or as a flexible sensing device for detecting human movement, breathing, swallowing, and surface deformation.

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