Method for peeling a liquid metal structure from a substrate

Abstract

One embodiment of the present invention is a peeling method for peeling a liquid metal structure formed of a gallium-based liquid metal and having an oxide film from a substrate, comprising: a preparation step in which a peeling device is provided that includes the liquid metal structure disposed on the surface of the substrate and a moving part that performs movement, and fixes one end of the liquid metal structure to one part; a peeling angle adjustment step in which one end of the liquid metal structure is fixed to an outer surface of the moving part or to a fixed part coupled to the moving part, and the moving part performs relative movement with respect to the substrate, thereby adjusting the peeling angle (θ) formed by the oxide film of the one end of the liquid metal structure with respect to the surface of the substrate to which the liquid metal structure is attached; and a peeling step in which the liquid metal structure is peeled from the substrate by maintaining the peeling angle at an angle satisfying the following [Equation 1].

Description

Technology Field

[0001] The present invention relates to a peeling method for peeling a liquid metal structure from a substrate, and more specifically, to a peeling method for peeling a liquid metal structure formed of liquid metal and having an oxide film (Ga2O3) from a substrate, which can be peeled from a substrate regardless of the material of the substrate and without leaving a residue on the surface of the substrate. Background Technology

[0003] Gallium-based liquid metals, such as gallium-indium eutectic alloys (EGaIn) or Galinstan, exist as liquids near room temperature and possess distinct advantages, including the ability to deform easily under external forces, the maintenance of high electrical conductivity even under deformation, and a nearly infinite fatigue failure life. Furthermore, these liquid metals are attracting significant attention due to their lower toxicity to the human body compared to well-known conventional liquid metals like mercury or cesium.

[0004] Due to the aforementioned characteristics, liquid metals are receiving a great deal of interest across fields including electronics, chemical engineering, chemistry, materials science, machinery, robotics, and medicine, and attempts to apply them are actively underway, particularly in fields such as flexible electronic devices, wearable devices, soft robots, and drug delivery systems.

[0005] Meanwhile, the liquid metal has an oxide film several nanometers thick on its surface containing gallium oxide (Ga2O3) formed by reacting with oxygen in the atmosphere. Due to this oxide film, the liquid metal exhibits combined liquid and solid behavioral characteristics. Specifically, the oxide film has tape-like adhesion properties due to Van der Waals forces on the substrate surface at the microscale.

[0006] However, since thin oxide films with a thickness of several nanometers tear easily, when wires are drawn with liquid metal on a substrate, applying tension to the wires to physically separate them from the substrate results in liquid metal residue remaining or failure to peel off properly.

[0007] Therefore, there is a need for technology that allows wires drawn with liquid metal to be easily removed from a substrate without undergoing complex processes, even after the wires have been drawn on the substrate with liquid metal once. Prior art literature

[0009] Korean Registered Patent Publication No. 10-1443248 (Publication Date: September 22, 2014) US Patent Application Publication US 2024 / 0032189 (Publication Date: January 25, 2024) Korean Published Patent Publication No. 10-2024-0151392 (Publication Date: October 18, 2024) The problem to be solved

[0010] The objective of the present invention, which aims to solve the above-mentioned problems, is to provide a method for cleanly peeling off a liquid metal structure formed of a liquid metal and an oxide film (Ga2O3) on the surface of the liquid metal from a substrate without leaving any residue, so that no residue remains on the surface of the substrate.

[0011] Furthermore, the objective of the present invention is to provide a method for peeling a liquid metal structure from a substrate, which can peel off a liquid metal structure formed of a liquid metal and an oxide film (Ga2O3) on the surface of the liquid metal from a substrate regardless of the material of the substrate.

[0012] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0014] The present invention, for achieving the above-mentioned purpose, comprises a peeling method for peeling a liquid metal structure formed of a gallium-based liquid metal and having an oxide film from a substrate, the method comprising: a preparation step in which a peeling device is provided that includes the liquid metal structure disposed on the surface of the substrate and a moving part that performs movement, and fixes one end of the liquid metal structure to one part; a peeling angle adjustment step in which one end of the liquid metal structure is fixed to an outer surface of the moving part or to a fixed part coupled to the moving part, and the moving part performs relative movement with respect to the substrate, thereby adjusting the peeling angle (θ) formed by the oxide film of the one end of the liquid metal structure with respect to the surface of the substrate to which the liquid metal structure is attached; and a peeling step in which the peeling angle is maintained at an angle satisfying the following [Equation 1], thereby peeling the liquid metal structure from the substrate. Effects of the invention

[0016] According to the present invention, a liquid metal structure can be peeled off from a substrate so that no residue remains on the surface of the substrate.

[0017] In addition, a liquid metal structure formed of liquid metal and an oxide film (Ga2O3) on the surface of the liquid metal can be peeled off from the substrate regardless of the material of the substrate.

[0018] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the invention or the claims. Brief explanation of the drawing

[0020] Figure 1 is an image of the execution of an experimental embodiment of the present invention. FIG. 2 is a schematic diagram of an image obtained by taking a picture of the boundary area between the substrate and the oxide film during the execution of an experimental example of the present invention, and the corresponding state. Figure 3 is a cross-sectional view illustrating the micromorphism of an oxide film near the contact line of a liquid metal structure attached to a substrate. Figure 4 is a diagram illustrating the forces acting on the oxide film portion represented by the dotted box in Figure 3. FIG. 5 is a schematic diagram illustrating the peeling of a non-stretchable film having a unit depth and a length of Δx by applying a tensile force of T per unit depth at a peeling angle (θ). FIG. 6 is a flowchart illustrating a peeling method for peeling a liquid metal structure from a substrate according to an embodiment of the present invention. FIG. 7 is a schematic diagram of the overall configuration of a peeling device including a rotating part of the present invention. FIG. 8 is a schematic diagram of the rotation in place of the rotating part of the present invention. FIG. 9 is a schematic diagram of the process of peeling off a liquid metal structure having an oxide film from a substrate using a peeling device according to the first embodiment of the present invention. FIG. 10 is a perspective view of a rotating part included in a peeling device according to a first embodiment of the present invention. FIG. 11 is a front view of a rotating part included in a peeling device according to a first embodiment of the present invention. FIG. 12 is a side view of a rotating part included in a peeling device according to a first embodiment of the present invention. FIG. 13 is an image of a peeling device according to the first embodiment of the present invention. FIGS. 14 and FIGS. 15 are side views of a rotating part included in a peeling device according to a second embodiment of the present invention. FIG. 16 is a side view of a rotating part included in a peeling device according to a third embodiment of the present invention. FIG. 17 is a perspective view of a rotating part included in a peeling device according to the fourth embodiment of the present invention. FIG. 18 is a schematic diagram of the configuration of a peeling device including a translational section of the present invention. FIG. 19 is an image of the process of peeling off a liquid metal structure having an oxide film from a substrate using a peeling device according to the fifth embodiment of the present invention. Specific details for implementing the invention

[0021] The present invention will be described below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0022] Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members interposed between them. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0023] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0024] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[0026] The present invention discloses a technique for peeling off a liquid metal structure (10) from a substrate (20) without leaving any residue on the surface of the substrate (20), regardless of the material of the substrate (20).

[0027] Here, the liquid metal (12) is a gallium-based liquid metal, and the liquid metal (12) may be Gallium, EGaIn (75 wt% gallium + 25 wt% indium) or Galinstan (68.5 wt% gallium + 21.5 wt% indium + 10 wt% tin).

[0028] Additionally, the liquid metal structure (10) may be in a state where an oxide film (Ga2O3) (11) is formed on the surface of a liquid metal (12) having a predetermined shape. The same applies below. In the following, the oxide film (11) refers to the oxide film (11) formed on the liquid metal structure (10).

[0029] As a result, it was concluded that in the process of applying tension T to the oxide film (11) on one end of the liquid metal structure (10) to peel off the liquid metal structure (10) on which the oxide film (11) is formed from the substrate (20), the peeling angle (θ) formed by the oxide film (11) on one end of the liquid metal structure (10) with respect to the surface of the substrate (20) to which the liquid metal structure (10) is attached must be maintained at an angle satisfying the following [Equation 1].

[0030] [Mathematical Formula 1]

[0031]

[0032] Here, E: Young's modulus of the oxide film (11), I: second moment of area of ​​the oxide film (11), G: peeling energy between the adherend (20) and the oxide film (11), z: unit depth, t: thickness of the oxide film (11), σ y: This is the yield stress of the oxide film (11) above.

[0034] In order to verify these theoretical research results, the present invention conducted an experiment to slowly lift an upper substrate (32) attached to an oxide film (11) of a liquid metal structure (10) to detach the liquid metal structure (10) having the oxide film (11) from a substrate-shaped substrate (20).

[0035] As a result, it was confirmed that the peeling of the liquid metal structure (10) having an oxide film (11) was successful only when the condition of [Mathematical Formula 1] above was satisfied.

[0036] Various methods can be used to apply tension to the oxide film (11) at one end of the liquid metal structure (10) to peel the liquid metal structure (10) from the substrate (20).

[0037] As an experimental example, the oxide film (11) on one end of the liquid metal structure (10) attached to the substrate (20) can be attached to an upper substrate (32) made of glass using double-sided tape (41), etc.

[0038] Next, the position of the upper substrate (32) is adjusted so that the peeling angle (θ) formed by the oxide film (11) on one end of the liquid metal structure (10) with respect to the surface of the substrate (20) to which the liquid metal structure (10) is attached becomes a predetermined angle, and then the upper substrate (32) is slowly lifted while the peeling angle (θ) is maintained at the predetermined angle, thereby applying tension to the one end of the liquid metal structure (10) attached to the upper substrate (32).

[0040] Figure 1 is an image of the execution of an experimental embodiment of the present invention.

[0041] Figure 1 (a) is a schematic diagram of an experimental setup for slowly lifting an upper substrate (32) attached to one end of a liquid metal structure (10) to detach a liquid metal structure (10) having an oxide film (11) from a substrate (20), and (b) is a schematic diagram of the change process of the part indicated by the dotted box according to the procedure for performing the peeling experiment.

[0042] Here, a liquid metal structure (10) is formed on the surface of a lower substrate (31) which is a substrate (20), a double-sided tape (41) for adhesive fixation is installed on the upper part of an oxide film (11) at one end of the liquid metal structure (10), and an upper substrate (32) can be installed on the upper part of the double-sided tape (41) and the oxide film (11).

[0043] This method requires manually pressing the upper substrate (32), setting the peeling angle (θ) to a predetermined angle, and then slowly lifting the upper substrate (32) while maintaining the peeling angle (θ) at the predetermined angle. Although it can be used for experiments, it is difficult to use it as a peeling device that can easily peel the liquid metal structure (10) from the substrate (20).

[0044] However, when the liquid metal structure (10) is peeled off from the substrate (20) while forming and maintaining the peeling angle (θ) by each process of FIG. 1, it can be confirmed that the liquid metal structure (10) can be easily peeled off from the substrate (20).

[0046] FIG. 2 is a schematic diagram of an image obtained by taking a picture of the boundary area between the substrate (20) and the oxide film (11) and the corresponding state when performing an experimental example of the present invention.

[0047] FIG. 2(a) visualizes an example in which peeling of the liquid metal structure (10) failed, and FIG. 2(b) visualizes an example in which peeling of the liquid metal structure (10) succeeded.

[0048] Hereinafter, in the description using Experimental Example 1 and Comparative Example 1, we will explain the details of the experiment performed using the peeling device of the experimental example of the present invention as shown in Fig. 1 above.

[0050] Experimental Example 1

[0052] In the atmosphere, tension was applied to the oxide film (11) on the surface of the liquid metal structure (10) formed of gallium indium eutectic alloy while maintaining a peeling angle of 50°, thereby peeling the liquid metal structure (10) from the substrate (20).

[0053] At this time, in order to observe the degree of retraction of the contact line and whether residue remains on the surface of the substrate (20), a substrate (glass) to which a liquid metal structure (10) is attached is prepared and a marker is applied near the initial contact line.

[0054] Referring to FIG. 2(b), in the case of Experimental Example 1, in which tension was applied to the oxide film (11) while maintaining the peeling angle at 50° according to the peeling method of the experimental embodiment of the present invention described above, it was confirmed that the liquid metal structure (10) was peeled off from the substrate (20) by retracting the contact line from the initial contact line position, and it was confirmed that the liquid metal (12) was peeled off cleanly without leaving any residue of liquid metal (12) on the surface of the peeled substrate (20).

[0056] Comparative Example 1

[0058] Tension was applied to the oxide film (11) under the same conditions as Experimental Example 1 above, except that the peeling angle was maintained at 20°.

[0059] Referring to FIG. 2(a), in the case of Comparative Example 1, in which tension was applied to the oxide film (11) while maintaining a peeling angle of 20°, it was confirmed that the contact line was the same as the initial contact line position, so the liquid metal structure (10) was not peeled off from the adherend (20) at all, and it was confirmed that the oxide film (11) was torn by the applied tension and reacted with the liquid metal (12) and oxygen in the atmosphere, and a new oxide film (11) was formed near the contact line.

[0061] Below, we will explain the theoretical basis for the derivation process of [Mathematical Formula 1].

[0062] FIG. 3 is a cross-sectional view showing the micro-shape of an oxide film (11) near the contact line of a liquid metal structure (10) attached to a substrate (20), FIG. 4 is a diagram showing the forces acting on the oxide film (11) portion represented by the dotted box in FIG. 3, and FIG. 5 is a schematic diagram showing peeling a non-stretchable film having a unit depth and a length of Δx by applying a tensile force of T per unit depth at a peeling angle (θ).

[0064] Derivation of the radius of curvature at point O where the oxide film has the minimum radius of curvature

[0066] Considering the curved oxide film (11) in the region near the contact line as illustrated in FIG. 3, the leftmost point O is the point where the oxide film (11) is assumed to have a minimum radius of curvature.

[0067] According to the two-dimensional beam bending theory, the radius of curvature R of a two-dimensional solid layer can be calculated using the following [Equation 1-1].

[0068] [Mathematical Formula 1-1]

[0069]

[0070] Here, E is the Young's modulus of the oxide film (11), I is the second moment of area, and M is the bending moment.

[0071] Assuming that the oxide film (11) has uniform bending stiffness, the radius of curvature R can be determined using the bending moment M.

[0073] Referring to FIG. 4, if we analyze the oxide film (11) portion represented by the dotted box in FIG. 3 with a focus on the point where the horizontal and vertical distances from point O are x and y, respectively, this portion is located at a point where the horizontal and vertical distances from point O are x and x, respectively. ∞ and y ∞ It extends to the position, where x ∞ and y ∞ is much larger than x and y.

[0074] x ∞ At the right end of the part where α is greater than 100 nm, the local slope approaches tanθ and the radius of curvature becomes virtually infinite.

[0076] Below, we will formulate the balance of moments near the left end of the oxide film (11).

[0077] At the right end, the oxide film (11) receives tension T without bending moment. This is because the local radius of curvature is infinite.

[0078] Also, the oxide film (11) is also subjected to a pressure of Δ from the internal liquid metal (12). Additionally, a tension T(x, y) and a bending moment M(x, y) are applied to the left end of the oxide film (11).

[0079] In the process of peeling the liquid metal structure (10) from the substrate (20), the pressure of the liquid metal (12) is associated with local flow, and therefore, the pressure of the liquid metal (12) is μU / (x ∞ tan 2 It is the unit (order) of θ.

[0080] As can be seen from the energy balance, tension T is of the order of G / (1+cosθ). Therefore, the ratio of pressure to tension is ΔP(x ∞- x) / T ~ μU(1+cosθ) / (Gtan 2 θ) ~ 10-4 It can be seen that ≪ 1. This indicates that the pressure of the liquid metal (12) is negligible compared to the effect of the bending moment.

[0082] Therefore, the moment balance at the left end of the oxide film (11) can be expressed as follows [Equation 1-2].

[0083] [Mathematical Formula 1-2]

[0084] M(x, y) = -(x ∞ - x)zTsinθ+ (y ∞ - y)zTcosθ

[0086] If we introduce the arc length s measured at point O along the oxide layer, R -1 It can be expressed as = -dΦ / ds. Here, Φ is the local angle between the tangent and the horizontal line of the oxide film (11), and z is the unit depth. Therefore, the equation R = EI / M is (x ∞ - x)zTsinθ - (y ∞ - y)zTcosθ = EI(dΦ / ds) can be rewritten. Differentiating this equation with respect to s yields [Equation 1-3] below.

[0087] [Mathematical Formula 1-3]

[0088] -cosΦzTsinθ+ sinΦzTcosθ= EId 2 Φ / ds 2

[0089] Here, dx / ds and dy / ds can be replaced with cosΦ and sinΦ, respectively.

[0091] This differential equation describes the distribution of Φ as a function of s for a given tension T, bending stiffness EI, and contact angle θ. Integrating this differential equation yields -sinΦzTsinθ - cosΦzTcosθ+ C = (EI / 2)(dΦ / ds) 2 It becomes, where C is the integration constant.

[0092] Assuming s → ∞, dΦ / ds → 0, and Φ → θ, C = T is determined.

[0093] At point O, x = 0 and Φ = π / 2. Therefore, the minimum radius of curvature R occurring at point O. O = {(dΦ / ds) x=0} -1 is R O ~ [EI / {Tz(1 - sinθ)}] 1 / 2 It is given as [Mathematical Formula 1-4] below.

[0094] [Mathematical Formula 1-4]

[0095]

[0097] Derivation of the relationship between peeling energy G and tension T in the process of peeling a liquid metal structure from a substrate

[0099] It can be inferred that peeling off the liquid metal structure (10) from the substrate (20) is similar to peeling off a thin solid film attached to the surface of a substrate.

[0100] Previous research has demonstrated that the process of peeling a thin solid film from a substrate varies depending on several factors, including peeling speed and peeling angle.

[0101] The experimentally determined relationship between the angle of peeling a non-stretchable film from a substrate, tension, and peeling energy is explained by the following energy equation [Equation 1-5] (see Fig. 5).

[0102] [Mathematical Formula 1-5]

[0103]

[0104] Here, T(1+cosθ)Δx on the left represents the work performed to peel a film by applying a tensile force T per unit depth to a film with a unit depth and a length of Δx at an angle θ. GΔx on the right represents the mechanical energy required to peel a film with a unit depth and a length of Δx. Peeling occurs when sufficient tension is applied according to θ to overcome the peeling energy.

[0106] Now, the mechanical energy required to remove the oxide film (11) from the substrate can be predicted.

[0107] In a system where two surfaces are bonded without a polymer adhesive, the peeling energy G is equal to the thermodynamic adhesive work W, which is defined as the reversible energy required to break intermolecular interactions per unit area at the interface.

[0108] However, peeling off the oxide film (11) also involves local movement of the liquid metal (12) encapsulated by the oxide film (11) near the contact line, which may result in additional energy dissipation. Therefore, the peeling energy G is the adhesive work W and the viscous dissipation Ψ that occurs near the contact line during the peeling process. * It can be expressed as the sum of.

[0110] Van der Waals interactions are the primary cause of adhesive work W, which is W = A / (12πd 2 It can be expressed as ). Here, A is the Hamaker constant determined by the two interaction surfaces, and d is the cutoff length representing the effective distance between the two surfaces.

[0111] In this invention, the Hamaker constant was estimated based on the Lifshitz theory, which depends on the refractive index and permittivity of the two materials, and the Hamaker constant for the interaction between gallium oxide and a base plate made of glass or PMMA is A, which is approximately 10 -19 It was calculated as J.

[0112] And, using a universal cutoff length of d = 0.2 nm, the resulting adhesion work W between the oxide layer and the underlying plate is approximately 0.1 J / m 2 It was calculated as.

[0114] Calculation of the extent to which viscous dissipation occurring near the contact line during the peeling process contributes to the peeling energy

[0116] Below, viscous dissipation Ψ with respect to peeling energy G * We will try to determine the extent of its contribution.

[0117] While the oxide film (11) is peeled off over a unit area, the dissipation at the sharp edges of the liquid metal structure (10) is Ψ * ~ μUl(θ - sinθcosθ) / (θ 2 - sin 2 It can be estimated as θ). Here, μ is the viscosity of the liquid metal (12), U is the flow velocity of the liquid metal (12), and l is a dimensionless coefficient related to the length scale.

[0118] In experiments for the present invention, μ ~ 10 -3 Pa·s, l ~ 10, Ψ * ~ 0.01U(θ - sinθcosθ) / (θ 2 - sin 2 It was calculated as θ). This indicates that the faster the dissipation rate and the smaller the contact angle, the greater the increase.

[0119] In experiments for the present invention, the smallest contact angle 10° and the maximum peeling speed U For 0.1 mm / s, Ψ * The upper limit of is approximately 10 -5 J / m 2 It is estimated as. According to scale analysis, in the experiment according to this study, Ψ * As implied by W, the viscous dissipation Ψ with respect to G * It can be seen that the contribution of can be ignored.

[0121] The minimum radius of curvature R of the oxide film expressed as a function of the peeling angle (θ) and peeling energy G. 0 Derivation of

[0123] By solving the above [Equation 1-4] and the above [Equation 1-5] simultaneously to eliminate the tension T, the minimum radius of curvature R0 of the oxide film (11) can be expressed as a function of the peeling angle (θ) and peeling energy G as shown in [Equation 1-6] below.

[0124] [Mathematical Formula 1-6]

[0125]

[0127] Below, we will examine the maximum allowable bending deformation of the oxide film (11).

[0128] Referring to the micro-shape (Fig. 3) of the oxide film (11) near the contact line of the liquid metal structure (10) attached to the substrate, the greatest elongation occurs in the outermost part of the convex surface near the contact line, thereby generating the maximum tensile stress.

[0129] The maximum stress at point O is σ = E ∈ It can be expressed as, and here ∈ is the strain at the outermost part of the convex surface.

[0130] Local strain is the thin film bending limit (t ≪ R O )at ∈ ~ t / R O It is given as follows. Here, since t is the thickness of the oxide film (11), σ ~ Et / R O am.

[0131] Local stress σ is the yield stress σ of oxide skin Y Failure may occur if it approaches. Yield limit of radius of curvature (R Y ) can be defined by the following [Mathematical Formula 1-7].

[0132] [Mathematical Formula 1-7]

[0133] R Y ~ Et / σ Y

[0135] Below this limit, local yielding of the oxide film (11) and subsequent destruction occur.

[0136] In the experiment for the present invention, E 4 GPa, σ Y 0.2 GPa and t R using 3 nm Y ~ Et / σY It was calculated as 60 nm. Therefore, the oxide film (11) can maintain a curved shape only when the radius of curvature is greater than about 60 nm, and deformation where the radius of curvature becomes smaller than 60 nm leads to failure.

[0138] Derivation of Mathematical Formula 1

[0140] The minimum radius of curvature R0 of the oxide film (11) is the minimum radius of curvature R at which yielding occurs. y Only in a larger state can the liquid metal structure (10) be peeled off from the substrate (20) without destroying the oxide film (11).

[0141] Therefore, R0 > R y If the above [Equation 1-6] and the above [Equation 1-7] are substituted into [Equation 1], the above [Equation 1] is derived.

[0143] Below, we will explain a method for peeling off liquid metal (12) from a substrate (20) using the above-mentioned principle.

[0144] FIG. 6 is a flowchart illustrating a peeling method for peeling a liquid metal structure (10) from a substrate (20) according to an embodiment of the present invention.

[0145] The peeling method of the present invention comprises a preparation step (S10); an acid vapor spraying step (S20); a peeling angle adjustment step (S30); and a peeling step (S40).

[0146] In the preparation step (S10), a liquid metal structure (10) disposed on the surface of the substrate (20) and a peeling device including a moving part and fixing one end of the liquid metal structure (10) to one part may be provided.

[0147] Here, the peeling device may optionally include a spraying part (330). Additionally, the peeling device may include a fixing part (210) that is coupled to a moving part and to which one end of the liquid metal structure (10) is fixed.

[0148] The liquid metal (12) may be an alloy comprising gallium; and one or more metals among indium, tin, lead, bismuth, aluminum, zinc, cadmium, mercury, and silver. Additionally, the liquid metal (12) may be a gallium-indium eutectic Ga-In alloy (EgaIn) or Galinstan.

[0149] The moving part may have the shape of a cylinder, cone, sphere, or polygonal polyhedron. In addition, the moving part may perform three-dimensional translational motion or rotational motion. Furthermore, the moving part may be formed from various materials such as metal, alloy, or synthetic resin.

[0150] Specifically, the moving part may be formed by the following rotating part or translational part. This will be explained in detail below.

[0151] The adherend (20) may be formed from one or more materials selected from the group consisting of metal, plastic, glass and silicone.

[0152] Specifically, the substrate (20) may include one or more selected from the group consisting of silicone, glass, metalloid, metal, acrylic resin, epoxy resin, ester resin, acrylate resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyamide (PA), polyurethane (PU), polyarylate (PA), polyethersulfone (PES), fluorene polyester (FPE), polycarbonate (PC), and cycloolefin resin.

[0153] More specifically, the substrate (20) may include one or more selected from the group consisting of germanium (Ge), gallium arsenide (GaAs), aluminum oxide (Al2O3), polycarbonate (PC), polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE) and octadecyltrichlorosilane (OTS).

[0154] However, the material of the adherend (20) described above is a specific example, and the material of the adherend (20) is not limited to the material described above.

[0156] In the acid vapor injection step (S20), acid vapor injected from the injection part (330) can come into contact with one end of the liquid metal structure (10).

[0157] As described above, the liquid metal structure (10) attached to the substrate (20) has an oxide film (Ga2O3) (11) with adhesive properties formed on its surface, and acid vapor can be brought into contact to remove the oxide film (11) on one end of the liquid metal structure (10).

[0158] When acid vapor is brought into contact with the oxide film (11) at one end of the liquid metal structure (10), the liquid metal (12) inside the liquid metal structure (10) is exposed to the area where the oxide film (11) at one end of the liquid metal structure (10) has been removed, and as oxidation of the liquid metal (12) exposed to the air occurs, a new oxide film (11) is formed, and as the leakage of the internal liquid metal (12) is stopped by the newly formed oxide film (11), the external shape of the liquid metal (12) attached to the substrate (20) can be deformed and fixed in a form surrounded by the new oxide film (11) on the surface.

[0159] In this process, the oxide film (11) that may have been damaged in the liquid metal structure (10) attached to the substrate (20) is completely replaced with a smooth new oxide film (11), making it easier to detach.

[0160] Specifically, the surface of one end of the liquid metal structure (10) before contact with acid vapor may not be smooth and may have a certain curvature formed thereon. When acid vapor is contacted with the surface of one end of the liquid metal structure (10) as described above, the oxide film on the surface of one end of the liquid metal structure (10) is removed by the acid vapor, and then a new oxide film is formed again in that area after the acid vapor spraying ends, thereby making the surface of one end of the liquid metal structure (10) smooth.

[0161] That is, after the existing oxide film is removed from a part of one end of the liquid metal structure (10) by acid vapor, a new oxide film is formed again in a part of one end of the liquid metal structure (10).

[0162] In this way, when the surface of one end of the liquid metal structure (10) is smooth, peeling can be easily performed when peeling the liquid metal structure (10) from the substrate (20).

[0163] Acid vapor may be the vapor of one or more acid solutions selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, bromic acid, and perchloric acid.

[0165] In the peeling step (S30), one end of the liquid metal structure (10) is fixed to the fixed part (210), and the rotating part performs rotation and relative movement with respect to the adherend (20), so that the liquid metal structure (10) can be peeled off from the adherend (20).

[0166] Here, tension can be stably applied to the oxide film (11) at one end of the liquid metal structure (10) through the fixing part (210), so that the liquid metal structure (10) can be stably peeled from the adherend (20) in the peeling step (S30).

[0167] Additionally, when the oxide film (11) of one end of the liquid metal structure (10) is fixed to the fixed part (210), the peeling angle (θ) can be set to a predetermined angle by the shape of the rotating part. At this time, in the peeling step (S30), the one end of the liquid metal structure (10) may be fixed to the fixed part (210) while the rotating part performs rotation and movement, or the rotation and movement of the rotating part may be performed after the one end of the liquid metal structure (10) is fixed to the fixed part (210) in advance.

[0168] In the peeling step (S30), the peeling angle (θ) can satisfy [Equation 1]. This is explained in detail above.

[0169] And, in the peeling step (S30), the peeling energy G between the substrate (20) of [Equation 1] and the oxide film (11) (Ga2O3) on the surface of the gallium-based liquid metal can be calculated using the following [Equation 2].

[0170] [Mathematical Formula 2]

[0171]

[0172] In [Equation 2], A is a Hamaker constant determined by the gallium-based liquid metal surface oxide film (Ga2O3) (11), the substrate (20), and the surrounding medium, and d0 is a cut-off length representing the effective distance between the surface of the substrate (20) and the surface of the gallium-based liquid metal oxide film (Ga2O3) (11).

[0173] The above Hamaker constant A is an intrinsic physical property value determined by the oxide film (11) on the surface of the gallium-based liquid metal, the substrate (20), and the surrounding medium, and can be calculated by the following mathematical formula 3.

[0174] The above Hamaker constant A is an intrinsic physical property value determined by the oxide film (11) on the surface of the gallium-based liquid metal, the substrate (20), and the surrounding medium, and can be calculated by the following mathematical formula 3.

[0175] [Mathematical Formula 3]

[0176]

[0177] Here, k B ε is the Boltzmann constant, T is the temperature, and ε Ⅰ is the dielectric constant of the oxide film (11), and ε Ⅱ is the dielectric constant of the adherend (20), and ε m n is the dielectric constant of the surrounding medium (air in this embodiment), and h p is Planck's constant, and ν e is the absorption frequency.

[0178] And, n Ⅰ is the refractive index of the oxide film (11), and n Ⅱ is the refractive index of the adherend (20), and n m The refractive index of the surrounding medium (air in this embodiment) is disclosed in the description of the peeling device of the present invention.

[0179] In this embodiment, k B T ≈ 4 × 10 -21 J and h p ν e ≈ 2x10 -18 It was assumed that J is the standard, and the cutoff length was assumed to be the standard cutoff length, so d0 = 0.2 nm. The dielectric constant (ε) and refractive index (n) for each material can be calculated using the values ​​listed in [Table 1] below.

[0180] [Table 1]

[0181]

[0183] The remaining details regarding the peeling method of the present invention as described above are disclosed in the description of the peeling device of the present invention below.

[0185] Hereinafter, the peeling device of the present invention according to each embodiment utilizing the above-described principle will be described.

[0186] As shown in FIGS. 7 to 19, the moving part may be formed as a rotating part or a translational part, and is not limited thereto, but a rotating part and a translational part will be described as specific embodiments.

[0187] FIG. 7 is a schematic diagram of the overall configuration of a peeling device including a rotating part of the present invention.

[0188] As shown in FIG. 7, the peeling device of the present invention comprises: a rotating part having a curved surface that is rotatable and moves around a rotation axis (101); and a fixing part (210) formed on the curved surface of the rotating part and fixed by contacting an oxide film (11) at one end of a liquid metal structure (10).

[0189] Here, depending on the rotation and movement of the rotating part, the peeling angle (θ) formed by the oxide film (11) at one end of the liquid metal structure (10) with respect to the surface of the substrate (20) to which the liquid metal structure (10) is attached is maintained at a predetermined angle, and the peeling of the liquid metal structure (10) can be performed.

[0190] Additionally, the peeling device of the present invention may include: a spraying unit (330) that sprays acid vapor toward an oxide film (11) at one end of a liquid metal structure (10); a support unit (310) that supports a rotating unit; and a driving unit (320) that transmits power to the rotating unit and performs movement.

[0191] Here, the rotating part can be formed in various shapes, specifically, it can have shapes such as a conical, cylindrical, or spherical shape, and can be formed in a shape including a circular cross-section perpendicular to the axis of rotation. Each embodiment will be described in detail below.

[0192] The rotating part is provided with a bar-shaped rotating shaft (101) that serves as the rotation center of the rotating part, and a support part (310) may be formed at both ends of the rotating shaft (101) so as to be rotatably coupled and supported by the rotating shaft (101).

[0193] Here, the lower portion of the support member (310) may be coupled with the rotation shaft (101) and the upper portion of the support member (310) may be coupled with the driving member (320), and the driving member (320) may be equipped with a motor, and the power of the motor may be provided to the rotating member by the operation of the motor so that the rotating member may rotate.

[0194] Also, the drive unit (320) itself can perform three-dimensional movement, and the movement of the rotating unit can also be performed according to the movement of the drive unit (320). To this end, the drive unit (320) can be combined with gantry equipment, but the drive unit (320) can be combined with equipment other than gantry equipment to perform the movement of the drive unit (320).

[0195] The fixed portion (210) may be formed from a material having a higher Hamaker constant compared to the substrate (20). In this case, the fixed portion (210) may be directly attached to part or the entire surface of the rotating portion, or a groove may be formed in the curved surface of the rotating portion and the fixed portion (210) may be installed in the groove. Alternatively, the fixed portion (210) may be formed from an adhesive polymer layer or a coating layer of liquid metal.

[0196] In the case where the fixing part (210) is installed in the groove on the outer surface of the rotating part as described above, during the process in which tension is applied to the oxide film (11) on one end of the liquid metal structure (10) through the fixing part (210) as the rotating part rotates, the fixing part (210) can be prevented from being pushed laterally on the outer surface of the rotating part and changing its installation position.

[0197] When a fixed part (210) is formed as described above, an oxide film (11) of one end of a liquid metal structure (10) can be fixed by being adhered or bonded to the fixed part (210). After the oxide film (11) of one end of the liquid metal structure (10) is fixed to the fixed part (210) as described above, when the rotating part rotates, tension can be applied to the oxide film (11) of one end of the liquid metal structure (10), and thereby, the liquid metal structure (10) can be separated from the adherend (20).

[0198] And, the fixed part (210) may be composed of gallium oxide (Ga2O3).

[0199] Since the fixing part (210) is composed of gallium oxide having viscous and adhesive properties, when the oxide film (11) of one end of the liquid metal structure (10) attached to the substrate (20) comes into contact with the fixing part (210), the oxide film (11) of one end of the liquid metal structure (10) can be well fixed to the fixing part (210) due to the strong adhesive properties.

[0200] The spraying unit (330) described above can perform three-dimensional movement, and before peeling off the liquid metal structure (10), the spraying unit (330) that has moved close to the oxide film (11) at one end of the liquid metal structure (10) can spray acid vapor onto the oxide film (11) at one end of the liquid metal structure (10), and the acid vapor can come into contact with the oxide film (11) at one end of the liquid metal structure (10).

[0201] The spraying unit (330) that sprays acid vapor onto the oxide film (11) at one end of the liquid metal structure (10) can be separated again from the oxide film (11) at one end of the liquid metal structure (10).

[0202] In this case, acid vapor is brought into contact with the oxide film (11) at one end of the liquid metal structure (10) attached to the substrate (20) to remove some of the oxide film (11) at the contact area, and the surface of the liquid metal (12) exposed to the air at the end of the liquid metal structure (10) from which some of the oxide film (11) has been removed is oxidized, so that the interface shape between the liquid metal (12) and the oxide film (11) at the part in contact with the acid vapor can be changed smoothly.

[0203] At this time, the acid vapor used may be the vapor of one or more acid solutions selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, bromic acid, and perchloric acid.

[0204] When acid vapor is brought into contact with the oxide film (11) on the surface of the liquid metal (12), the oxide film (11) on the surface of the liquid metal (12) is removed, and the liquid metal (12) inside is exposed through the area where the oxide film (11) was removed. As oxidation of the liquid metal (12) occurs on the surface of the liquid metal (12) exposed to the air, a new oxide film (11) is formed. As the leakage of the liquid metal (12) inside is stopped by the newly formed oxide film (11), the shape of the liquid metal (12) attached to the substrate is deformed and fixed in a form surrounded by the new oxide film (11) on the surface.

[0205] In this process, the oxide film (11) that may have been damaged in the liquid metal structure (10) attached to the substrate (20) is completely replaced with a smooth new oxide film (11), making it easier to detach.

[0206] Specifically, the surface of one end of the liquid metal structure (10) before contact with acid vapor may not be smooth and may have a certain curvature formed thereon. When acid vapor is brought into contact with the surface of one end of the liquid metal structure (10) as described above, the oxide film on the surface of one end of the liquid metal structure (10) is removed by the acid vapor and then re-formed after the acid vapor spraying ends, thereby allowing the surface of one end of the liquid metal structure (10) to be formed smoothly.

[0207] In this way, when the surface of one end of the liquid metal structure (10) is smooth, peeling can be easily performed when peeling the liquid metal structure (10) from the substrate (20).

[0208] FIG. 8 is a schematic diagram of the rotation of the rotating part of the present invention in place. FIG. 8 (a) is a state in which the outer surface of the rotating part is in contact with the oxide film (11) on the surface of the liquid metal (12), and FIG. 8 (b) is a state in which the rotating part performs rotation in place.

[0209] As shown in FIG. 8, before the movement of the rotating part, the rotating part can perform rotation in place when the outer surface of the rotating part or the fixed part (210) is in contact with the oxide film (11).

[0210] Specifically, before the rotational part moves to peel off the liquid metal (12), the oxide film (11) on the surface of the liquid metal (12) is in contact with the outer surface portion of the rotational part where the fixed part (210) is formed, and then the rotational part can perform rotation in place.

[0211] And, by rotating the rotating part in place as shown in Fig. 8 (b), the angle of inclination (α) of the part in contact with the outer surface of the rotating part at one end of the liquid metal structure (10) can be adjusted in the cross-section of the rotating part perpendicular to the rotation axis of the rotating part.

[0212] Specifically, as the inclination angle (α) above decreases due to the rotation of the rotating part, the oxide film (11) at one end of the liquid metal structure (10) is damaged, and thereby the liquid metal (12) can be stably fixed to the fixed part (210).

[0213] At this time, as described above, the inclination angle (α) formed by the oxide film (11) at one end of the liquid metal structure (10) on the surface of the liquid metal (12) with respect to the surface of the substrate (20) to which the liquid metal (12) is attached can be formed within the range of the angle (θ') according to the following [Equation 1a], which is a modified form of the above [Equation 1].

[0214] That is, [Equation 1a] may be an equation for the range of inclination angle (α) formed before peeling of the liquid metal structure (10).

[0215] [Mathematical Formula 1a]

[0216]

[0217] By forming the inclination angle (α) within the range satisfying [Equation 1a] through the rotation of the rotating part in place, the oxide film (11) on the surface of the liquid metal (12) is broken, and the liquid metal (12) can be stably fixed to the fixed part (210).

[0219] First, a peeling device according to the first embodiment of the present invention will be described.

[0220] FIG. 9 is a schematic diagram of the process of peeling off a liquid metal structure (10) having an oxide film (11) from a substrate (20) using a peeling device according to the first embodiment of the present invention.

[0221] Here, FIG. 9(a) is a front view of the first rotating part (110) in its initial rotational state, and FIG. 9(b) is a side view of the first rotating part (110) in its initial rotational state. FIG. 9(c) is a front view of the first rotating part (110) in its rotational state, and FIG. 9(d) is a side view of the first rotating part (110) in its rotational state.

[0222] In addition, FIG. 10 is a perspective view of a rotating part included in a peeling device according to a first embodiment of the present invention, and FIG. 11 is a front view of a rotating part included in a peeling device according to a first embodiment of the present invention.

[0223] Also, FIG. 12 is a side view of a rotating part included in a peeling device according to the first embodiment of the present invention, and FIG. 13 is an image of the peeling device according to the first embodiment of the present invention.

[0224] As shown in FIGS. 7 to 13, the peeling device according to the first embodiment of the present invention is a peeling device for peeling a liquid metal structure (10) from a substrate (20), and the first rotating part (110) of the first embodiment may be configured to include a cylindrical roller (111) and a tapered roller (112). Here, the cylindrical roller (111) and the tapered roller (112) may be formed integrally.

[0225] The cylindrical roller (111) is a component that moves relative to the workpiece (20) while rotating in contact with the surface of the workpiece (20), and can be configured to rotate around a rotation axis (101), and the cylindrical roller (111) can perform rolling motion by receiving force through the rotation axis (101).

[0226] The tapered roller (112) is a component that rotates together with the rotation of the cylindrical roller (111), and may be a component whose outer surface is formed to be inclined at a predetermined taper angle toward the rotation axis (101).

[0227] The fixed part (210) may be formed on the outer surface of the tapered roller (112), and at this time, as described above, the fixed part (210) may be installed directly on the outer surface of the tapered roller (112) or may be installed by being inserted into a groove formed on the outer surface of the tapered roller (112).

[0228] In this peeling device, due to the attachment characteristics of the fixing part (210), the oxide film (11) of one end of the liquid metal structure (10) attached to the substrate (20) is fixed to the fixing part (210), and due to the taper angle of the tapered roller (112), a gap is formed between the tapered roller (112) and the substrate (20) even when the cylindrical roller (111) is in contact with the substrate (20), so that the liquid metal structure (10) can be easily placed in the space between the outer surface of the tapered roller (112) and the substrate (20), and the liquid metal structure (10) can be easily fixed to the fixing part (210).

[0229] At this time, the taper angle of the tapered roller (112) or the position of the fixed part (210) can be pre-set to facilitate the formation of a peeling angle (θ) by taking into account the thickness of the liquid metal structure (10) and applied to the tapered roller (112).

[0231] Next, a peeling device according to the second embodiment of the present invention will be described.

[0232] FIGS. 14 and FIGS. 15 are side views of a rotating part included in a peeling device according to a second embodiment of the present invention. Here, FIG. 14 (a) is a state in which the second rotating part (120) is in contact with an oxide film (11) on the upper side of the liquid metal (12), and FIG. 14 (b) is a state in which the liquid metal (12) is peeled from the adherend (20) according to the rotation and movement (rolling) of the second rotating part (120). FIG. 15 is a state in which the second rotating part (120) performs rotation and movement while in contact with an oxide film (11) on the lower side of the liquid metal (12).

[0233] As seen in FIGS. 14 and 15, the second rotating part (120), which is the rotating part of the second embodiment, can be formed in the shape of a cylinder.

[0234] First, as shown in FIG. 14, when the second rotating part (120) comes into contact with the oxide film (11) on the upper part of the liquid metal (12), the second rotating part (120) can be positioned at a constant distance from the surface of the substrate (20) by the operation of the driving part (320), and thereby the liquid metal structure (10) can be easily placed in the space between the outer surface of the second rotating part (120) and the substrate (20).

[0235] And, when the rotation and movement (rolling) of the second rotating part (120) is performed, one end of the liquid metal structure (10) is fixed to the fixed part (210), and the peeling of the liquid metal structure (10) from the adherend (20) can be easily performed.

[0236] At this time, the gap between the second rotating part (120) and the adherend (20) is pre-set to facilitate the formation of a peeling angle (θ) by taking into account the thickness of the liquid metal structure (10), and can be applied to the movement and rotation of the second rotating part (120).

[0237] Next, as shown in FIG. 15, when the second rotating part (120) performs rotation and movement while in contact with the oxide film (11) at the bottom of the liquid metal structure (10), the second rotating part (120) initially presses the oxide film (11) at one end of the liquid metal structure (10) by the operation of the driving part (320), and at this time, the oxide film (11) at one end of the liquid metal structure (10) is damaged by a predetermined rotation in place, and the one end of the liquid metal structure (10) can be fixed to the fixed part (210).

[0238] At this time, as one end of the liquid metal structure (10) is fixed to the fixed part (210) of the second rotating part (120), a peeling angle (θ) can be formed on the oxide film (11). Then, by moving the driving part (320), the second rotating part (120) is separated from the substrate (20), and peeling of the liquid metal structure (10) from the substrate (20) is performed. Afterward, by performing rotation and movement (x-axis movement) of the second rotating part (120), continuous peeling of the liquid metal structure (10) can be performed.

[0240] FIG. 16 is a side view of a rotating part included in a peeling device according to a third embodiment of the present invention.

[0241] As shown in FIG. 16, the third rotating part (130), which is the rotating part of the third embodiment, can be formed in the shape of a sphere.

[0242] The third rotating part (130) is a component that moves relative to the workpiece (20) while rotating in contact with the surface of the workpiece (20), and can be configured to rotate around a rotation axis (101), and can perform rolling motion by receiving force through the rotation axis (101).

[0243] And, at this time, the area around the contact surface of the third rotating part (130) that contacts the substrate (20) can be spaced apart from the substrate (20).

[0244] The fixed part (210) may be formed on the outer surface of the third rotating part (130), and at this time, as described above, the fixed part (210) may be installed directly on the outer surface of the third rotating part (130) or may be installed by being inserted into a groove formed on the outer surface of the third rotating part (130).

[0245] In this peeling device, due to the attachment characteristics of the fixed part (210), the oxide film (11) on one end of the liquid metal structure (10) attached to the substrate (20) is fixed to the fixed part (210), and a gap is formed between the contact surface area of ​​the third rotating part (130) and the substrate (20), so that the liquid metal structure (10) can be easily placed in the space between the contact surface area of ​​the third rotating part (130) and the substrate (20), and the liquid metal structure (10) can be easily fixed to the fixed part (210).

[0246] At this time, the diameter of the third rotating part (130) or the position of the fixed part (210) can be pre-set and applied to the third rotating part (130) in such a way that the peeling angle (θ) is easily formed by taking into account the thickness of the liquid metal structure (10).

[0248] FIG. 17 is a perspective view of a rotating part included in a peeling device according to the fourth embodiment of the present invention.

[0249] As shown in FIG. 17, the fourth rotating part (140) of the fourth embodiment may be formed in a cylindrical shape, and a movable fixed part (220) that performs movement may be formed as a film-shaped fixed part (210) that wraps around the outer surface of the fourth rotating part (140).

[0250] When the fourth rotating part (140) comes into contact with the oxide film (11) on the upper surface of the liquid metal (12), the fourth rotating part (140) can be positioned at a constant distance from the surface of the substrate (20) by the operation of the driving part (320), and thereby the liquid metal structure (10) can be easily placed in the space between the outer surface of the fourth rotating part (140) and the substrate (20).

[0251] Additionally, the oxide film (11) can be fixed to the movable fixed part (220). Then, when the rotation and movement (rolling) of the fourth rotating part (140) is performed, the movable fixed part (220) also moves like a conveyor belt while in contact with the fourth rotating part (140) according to the rotation of the fourth rotating part (140), and thereby, the peeling of the liquid metal structure (10) from the substrate (20) can be easily performed.

[0252] At this time, the gap between the fourth rotating part (140) and the adherend (20) is pre-set to facilitate the formation of a peeling angle (θ) by taking into account the thickness of the liquid metal structure (10), and can be applied to the movement and rotation of the fourth rotating part (140).

[0254] FIG. 18 is a schematic diagram of the configuration of a peeling device including a translational section of the present invention. FIG. 19 is an image of the process of peeling a liquid metal structure having an oxide film from a substrate using a peeling device according to the fifth embodiment of the present invention.

[0255] In FIG. 19, (a-1) to (a-5) represent a state where the peeling angle is not formed and the peeling of the liquid metal structure (10) is incomplete, and (b-1) to (b-5) represent a state where the peeling of the liquid metal structure (10) is complete due to the formation of the peeling angle.

[0256] Here, images (a-1) through (a-5) are arranged in chronological order, and images (b-1) through (b-5) are also arranged in chronological order.

[0257] As seen in FIG. 18, the translational section (400) can be formed in a cylindrical shape, and the translational section (400) can perform vertical linear movement (translational movement).

[0258] At this time, the peeling device of the present invention may include a translation unit (400); a spraying unit (330) that sprays acid vapor toward an oxide film (11) at one end of a liquid metal structure (10); and a driving unit (320) that operates the translation unit (400) in conjunction with the translation unit (400).

[0259] The remaining details regarding the injection part (330) and the driving part (320) are the same as the description of the peeling device including the rotating part described above.

[0260] A liquid metal structure (10) may be fixed to the bottom of the translational section (400) by the fixed section (210), and a groove may be formed on the bottom surface of the translational section (400). The remaining details regarding the fixed section (210) are the same as the details regarding the fixed section, except for the description regarding the rotation of the fixed section in the peeling device including the rotating section described above.

[0261] In the above-described peeling angle adjustment step (S30), the translational part (400) spaced apart from the upper part of the liquid metal structure (10) is slowly lowered to bring the fixed part (210) and the liquid metal structure (10) into contact, and then the translational part (400) is continuously lowered to adjust the lowering distance of the translational part (400) so that the peeling angle (θ) of the liquid metal structure (10) satisfies the above-described [Equation 1].

[0262] Then, after the translation unit (400) has finished descending to a preset descending distance, the translation unit (400) can be raised to detach the liquid metal structure (10) from the adherend (20).

[0263] In the present invention, a liquid metal structure (10) is formed at the lower part of the translation section (400), and translational movement in the up and down direction of the translation section (400) is performed, but it is obvious that three-dimensional translational movement in various directions of the translation section (400) can be performed depending on the position of the liquid metal structure (10).

[0264] As seen in (a-1) to (a-5) of FIG. 19, if the peeling angle (θ) does not satisfy the above [Equation 1] due to the vertical movement of the translational part (400), it can be confirmed that the peeling of the liquid metal structure (10) from the adherend (20) is not easy.

[0265] As seen in (b-1) to (b-5) of FIG. 19, when the peeling angle (θ) satisfies the above [Equation 1] due to the vertical movement of the translational part (400), it can be confirmed that the peeling of the liquid metal structure (10) on the adherend (20) is easily performed.

[0267] According to the peeling device according to each embodiment of the present invention as described above, the liquid metal (12) and the oxide film (11) on the surface of the liquid metal (12) can be peeled from the substrate (20) so that no residue remains on the surface of the substrate (20) regardless of the material of the substrate (20).

[0268] Below, experimental examples conducted in the present invention will be described to verify the theoretical research results.

[0270] Experimental Example 2

[0272] A substrate-shaped substrate (20) (glass (SiO₂)) was prepared, to which a line-shaped liquid metal structure (10) formed of a gallium indium eutectic alloy liquid metal (12) was attached.

[0273] And, as shown in FIG. 13, a peeling device according to the first embodiment of the present invention as described above was prepared.

[0274] First, a liquid metal structure (10) formed of a gallium indium eutectic alloy was attached to a fixed part (210), and a driving force was transmitted to a rotating shaft (101) to peel off the liquid metal structure (10) from a substrate (glass (SiO₂)) which is the adherend (20).

[0275] Referring to FIG. 12, the fixing part (210) containing gallium oxide installed on the outer surface of the tapered roller (112) has adhesion characteristics to the surface of the liquid metal (12) and functions to fix the liquid metal structure (10) to the tapered roller (112).

[0276] It was confirmed that tension was transmitted to the oxide film (11) on the surface of the liquid metal (12) through the rolling motion of the cylindrical roller (111), and that the liquid metal structure (10) formed of gallium indium eutectic alloy was cleanly peeled off from the substrate (glass (SiO₂)) which is the adherend (20).

[0278] When using the peeling device and peeling method of the present invention as described above, the liquid metal structure (10) can be peeled from the substrate (20) so that no residue remains on the surface of the substrate (20).

[0279] And, regardless of the material of the substrate (20), a liquid metal structure (10) formed of liquid metal (12) and an oxide film (11) on the surface of the liquid metal (12) can be peeled off from the substrate (20).

[0281] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0282] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0284] 10: Liquid metal structure 11: Oxide film 12: Liquid Metal 20: Adhesion 31: Lower substrate 32: Upper substrate 41: Double-sided tape 100: Rotating part 101: Rotation axis 110: First rotating part 111: Cylindrical roller 112: Tapered roller 120: Second rotating part 130: Third rotation section 140: 4th rotation section 210: Fixed part 220: Movable fixed part 310: Support 320: Drive unit 330: Injection part 400: Byeongjinbu

Claims

Claim 1 A peeling method for peeling a liquid metal structure formed of a gallium-based liquid metal and having an oxide film from a substrate, comprising: a preparation step in which a peeling device is provided for fixing one end of the liquid metal structure to a portion thereof, the liquid metal structure disposed on the surface of the substrate and a moving part that performs movement; a peeling angle adjustment step in which one end of the liquid metal structure is fixed to an outer surface of the moving part or to a fixed part coupled to the moving part, and the moving part performs relative movement with respect to the substrate, thereby adjusting the peeling angle (θ) formed by the oxide film of the one end of the liquid metal structure with respect to the surface of the substrate to which the liquid metal structure is attached; and a peeling step in which the liquid metal structure is peeled from the substrate by maintaining the peeling angle at an angle satisfying the following [Equation 1], wherein [Equation 1] Here, E: Young's modulus of the oxide film, I: second moment of area of ​​the oxide film, G: peeling energy between the adherend and the oxide film, z: unit depth, t: thickness of the oxide film, σ y A peeling method for peeling a liquid metal structure from a substrate, characterized by the yield stress of the oxide film. Claim 2 In paragraph 1, the above G is calculated by the following [Mathematical Formula 2], and [Mathematical Formula 2] A method for peeling a liquid metal structure from a substrate, characterized in that, where, A: a Hamaker constant determined by the oxide film, the substrate, and the surrounding medium, and d0: a cut-off length representing the effective distance between the surface of the substrate and the surface of the oxide film. Claim 3 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in claim 1, the moving part has the shape of a cylinder, cone, sphere, or polygonal polyhedron. Claim 4 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in paragraph 3, the fixed portion is formed on a part or the entire surface of the moving portion. Claim 5 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in paragraph 3, a groove is formed on the surface of the moving part and the fixed part is installed in the groove. Claim 6 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in claim 1, the moving part performs three-dimensional translational motion or rotational motion. Claim 7 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in the preparation step of claim 1, a spraying unit is further provided to spray acid vapor toward one end of the liquid metal structure. Claim 8 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in claim 7, an acid vapor spraying step is performed between the preparation step and the peeling angle adjustment step, wherein an acid vapor sprayed from the spraying part contacts one end of the liquid metal structure. Claim 9 A method for peeling a liquid metal structure from a substrate, characterized in that, in the acid vapor spraying step, an existing oxide film is removed from a portion of one end of the liquid metal structure by the acid vapor, and then a new oxide film is formed again at a portion of one end of the liquid metal structure. Claim 10 A method for peeling a liquid metal structure from a substrate, characterized in that, in claim 7, the acid vapor is the vapor of one or more acid solutions selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, bromic acid, and perchloric acid. Claim 11 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in claim 1, the liquid metal is an alloy comprising gallium; and one or more metals selected from indium, tin, lead, bismuth, aluminum, zinc, cadmium, mercury, and silver. Claim 12 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in claim 1, the liquid metal is a gallium indium eutectic Ga-In alloy (EgaIn) or Galinstan. Claim 13 A peeling method for peeling a liquid metal structure from a substrate, characterized in that, in claim 6, the rotating part, which is a moving part that performs rotational motion, includes a cone, cylinder, or sphere shape. Claim 14 A peeling method for peeling a liquid metal structure from a substrate, wherein, in claim 1, the substrate is formed of one or more materials selected from the group consisting of metal, plastic, glass, and silicone.

Images