Prediction device and prediction method of buckling peeling structure

Abstract

To provide a prediction device of a buckling peeling structure capable of predicting the three-dimensional shape of the swellable thin film formed by a buckling peeling method.SOLUTION: A prediction device 100 of a buckling peeling structure according to the present invention is the prediction device of a buckling peeling structure formed by the partial peeling of the swellable thin film adhered to one surface of a base plate. The prediction device comprises a peeling area input part 101 to input the peeling area pattern of a swellable thin film in one surface of a base plate, a parameter input part 102 of the swellable thin film to input the parameters of the swellable thin film required for a finite element analysis, a finite element analysis part 103 to analyze the buckling peeling shape of the swellable thin film obtained each time the buckling peeling occurred by increasing a welling rate based on the finite element method using the parameters, and a storage part 104 of the buckling peeling shape data to store the obtained buckling peeling shape data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for predicting and calculating, by finite element analysis, the three-dimensional structure of buckling and delamination shapes that occur due to swelling in a laminate of a solid substrate and a swellable thin film with a controlled adhesive interface. [Background technology]

[0002] Swellable materials, which can change shape (volume) by the addition or removal of solvents, are attracting attention as motion elements that generate displacement and force in a wide range of fields, including medicine, biology, and robotics (Non-Patent Document 1). In particular, thin-film swellable materials (swellable thin films) have the advantage of being able to reproduce the physical properties, characteristics, and movements of real living organisms due to their flexibility and response speed, and are therefore expected to have great potential.

[0003] To expand the range of applications of such swellable thin films, it is necessary to be able to control their shapes in various ways to suit the application. As an example of shape control, a method using buckling delamination is disclosed in Patent Document 1 and Non-Patent Document 2. According to this method, by controlling the adhesive interface between the solid substrate and the swellable thin film, the pressure increase due to swelling can be used as a trigger to delaminate the swellable thin film at any desired location. Therefore, by controlling the delamination pattern and various parameters related to the physical properties of the swellable thin film, parts of the swellable thin film can be raised three-dimensionally, allowing the creation of a wide variety of shapes.

[0004] However, it is difficult to predict the 3D shape that will be created from the various controlled parameters. To actually obtain the desired 3D shape, it is necessary to actually create the 3D shape using the various parameters, understand the relationship between the parameters and the 3D shape, and then refer to that relationship to select the parameters that correspond to the desired 3D shape. These tasks require a huge amount of effort and time, and reducing the burden on the people performing the work is a challenge. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-062843 [Non-patent literature]

[0006] [Non-Patent Document 1] R. Takahashi, et al. Adv. Funct. Mater, 33, 2300184 (2023). [Non-patent document 2] Bionics Technology Opening Up the Future of Medical Health | NTT Technical Journal, May 2021. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a prediction device and method for buckling peeling structures that enable prediction of the three-dimensional shape of swellable thin films produced by the buckling peeling method. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following means.

[0009] (1) A prediction device for buckling peeling structures according to one embodiment of the present invention is a prediction device for buckling peeling structures formed by the peeling of a portion of a swellable thin film adhered to one surface of a substrate, and includes a peeling area input unit for inputting the pattern of the peeling area of ​​the swellable thin film on one surface of the substrate, a swellable thin film parameter input unit for inputting parameters of the swellable thin film required for finite element analysis, a finite element analysis unit for analyzing the buckling peeling shape of the swellable thin film obtained by the finite element method using the parameters each time the swelling rate increases and buckling peeling occurs, and a buckling peeling shape data storage unit for storing data on the obtained buckling peeling shape.

[0010] (2) A method for predicting a buckling peeling structure according to one embodiment of the present invention is a method for predicting a buckling peeling structure formed by peeling off a portion of a swellable thin film adhered to one surface of a substrate, and includes the following steps: a peeling area input step for inputting the pattern of the peeling area of ​​the swellable thin film on one surface of the substrate; a swellable thin film parameter input step for inputting parameters of the swellable thin film required for finite element analysis; a finite element analysis step for analyzing the buckling peeling shape of the swellable thin film obtained by the finite element method using the parameters each time the swelling rate increases and buckling peeling occurs; and a buckling peeling shape data storage step for storing data on the obtained buckling peeling shape. [Effects of the Invention]

[0011] The device and method for predicting a buckling peeling structure of the present invention make it possible to predict the three-dimensional shape of a swellable thin film produced by the buckling peeling method. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram schematically illustrating the configuration of a prediction device for buckling and peeling structures according to an embodiment of the present invention. [Figure 2] 1(a) and 1(b) are a plan view and a cross-sectional view of a structure provided with a swellable thin film of Example 1. FIG. [Figure 3] 1(a) to 1(c) are diagrams comparing the buckling and peeling structures obtained by changing the swelling degree in the structure of Example 1. FIG. [Figure 4] FIG. 10 is a plan view of a structure provided with a swellable thin film according to Example 2. [Figure 5] FIG. 10 is a perspective view of the structure of Example 2, showing a state in which the swellable thin film is buckled and peeled off. [Figure 6] 10 is an image of the structure of Example 2 in a state where the swellable thin film is buckled and peeled. [Figure 7] 10(a) to 10(f) are diagrams comparing the buckling peeling structures obtained by changing the peel width in the structure of Example 3. FIG. [Figure 8] FIG. 10 is a diagram comparing the buckling and peeling structures obtained by changing the swelling degree in the structure of Example 3. [Figure 9] 10(a) to 10(d) are simulation output diagrams comparing the buckling and peeling structures obtained by changing the physical property values ​​in the structure of Example 4. [Figure 10] 10(a) to 10(d) are observation images comparing the buckling and peeling structures obtained by changing the physical property values ​​in the structure of Example 4. [Figure 11] (a) Graph showing the relationship between the crosslink density of the hydrogel and the height of the raised buckling peeling structure. (b) Graph showing the relationship between the crosslink density of the hydrogel and the period of the shape change of the buckling peeling structure. [Figure 12] FIG. 10 is a perspective view of a structure provided with a swellable thin film of Example 5. [Figure 13] 10(a) and 10(b) are perspective views of the structure of Example 5, showing the state in which the swellable thin film is buckled and peeled off. [Figure 14] 10(a) and 10(b) are images of the structure of Example 5 in which the swellable thin film is actually buckled and peeled off. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a detailed description will be given of a prediction device and a prediction method for buckling and peeling structures according to an embodiment of the present invention, with reference to the accompanying drawings. Note that the drawings used in the following description may show characteristic portions enlarged for ease of understanding, and the dimensional ratios of the components may not be the same as those in reality. Furthermore, the materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate modifications may be made within the scope of the present invention.

[0014] 1 is a diagram schematically illustrating the configuration of a buckling and peeling structure prediction device 100 according to one embodiment of the present invention. The buckling and peeling structure prediction device 100 mainly comprises a peeling region input unit 101, a swellable thin film parameter input unit 102, a finite element analysis unit 103, and a buckling and peeling shape data storage unit 104.

[0015] The method for predicting a buckling peeling structure of this embodiment is a method for predicting a buckling peeling structure formed by partial peeling of a swellable thin film adhered to one surface of a substrate, using a buckling peeling structure prediction device 100. The method for predicting a buckling peeling structure mainly includes a peeling region input step, a swellable thin film parameter input step, a finite element analysis step, and a buckling peeling shape data storage step.

[0016] (Peeling area input process) In the peeling region input step, a pattern of a peeling region of a swellable thin film on one surface of a substrate (solid substrate) is input. The peeling region input unit 101 is a means (element, functional unit) that executes this input. Any peeling region pattern can be created and input in the peeling region input unit 101. The shape of the input pattern is not particularly limited; for example, a rectangular pattern may be input, or a pattern of another shape, or a complex pattern combining multiple shapes may be input. Patent Document 1 (paragraph

[0089] ) discloses an example of providing a rectangular pattern peeling region.

[0017] By systematically varying the size of the input peel region pattern, it is possible to precisely profile the resulting three-dimensional structure. For example, if the thickness of the swellable thin film is approximately 100 μm, the shape of the peel region on one side is rectangular, and the three-dimensional structure of the swellable thin film formed by buckling peeling on the rectangular pattern is predicted, the width of the rectangular pattern should be set to a value in 100 μm increments within the range of approximately 100 μm to 3000 μm. Note that the width of the rectangular pattern here refers to the length of a pair of opposing sides of the rectangle.

[0018] Furthermore, for example, the thickness of the swellable thin film may be about 100 μm, and the shape of the peeled region on one surface may be configured to be composed of a central portion and extension portions extending from the central portion in multiple directions (two or three or more directions).When predicting the three-dimensional structure of the swellable thin film formed by buckling and peeling on the pattern of the extension portions, it is recommended to set the pattern width of the extension portions to a value in 100 μm increments in the range of about 100 μm to 3000 μm.

[0019] An adhesive region of the swellable thin film must be provided around the peel region. The size (area) and shape of the adhesive region are not particularly limited. However, from the viewpoint of ensuring a stable adhesive state, it is preferable that the adhesive region has a width of about 300 μm in at least one direction.

[0020] (Swelling thin film parameter input process) In the swellable thin film parameter input step, the parameters of the swellable thin film required for analysis using the finite element method are input. The swellable thin film parameter input unit 102 is a means (element, functional unit) for executing this input. In the swellable thin film parameter input unit 102, parameters such as the film thickness, elastic modulus, Poisson's ratio, and linear swelling rate (degree of linear swelling) of the swellable thin film can be input in order to perform calculations using the finite element method. It is preferable to use values ​​obtained through experiments (actual measured values) as the input parameters, but values ​​predicted by other methods, such as simulation, may also be used.

[0021] The swellable thin film is not particularly limited, but may be, for example, a material that swells in water (hydrogel) or a material that swells in an organic solvent (rubber material, etc.). Furthermore, the swellable thin film is not limited to one that swells when a solvent enters or leaves it, and may be, for example, a metal material, a polymer material, or the like that changes volume (de-swells) when exposed to a specific stimulus such as heat.

[0022] The film thickness value of the swellable thin film may be, for example, a value obtained by direct observation, a value measured with a film thickness meter, a value estimated from the thickness of a spacer used during film formation, or a value obtained by other methods.

[0023] The modulus of elasticity of the swellable thin film may be a value calculated from the initial gradient (inclination) of a stress-strain curve obtained by, for example, a tensile test or a compression test, or a value obtained by other methods.

[0024] The Poisson's ratio of the swellable thin film may be a literature value corresponding to the material, but it is preferable to use an experimental value. When the swellable thin film is made of a hydrogel or rubber material, the Poisson's ratio may be set to a value of approximately 0.46 to 0.49, taking into account incompressibility.

[0025] The linear swelling degree of a swellable thin film can be determined from literature values ​​for the material, but experimental values ​​are preferred. For example, a circular area with a diameter of D0 is cut out from the swellable thin film before swelling and allowed to swell in a specified solvent until the size change reaches equilibrium. The linear swelling degree can be calculated from the ratio (D / D0) of the diameter D after full swelling to the diameter D0 before swelling.

[0026] (Finite element analysis process) In the finite element analysis step, the buckling and peeling shape of the resulting swellable thin film is analyzed by the finite element method using the parameters input in the swellable thin film parameter input unit 102, each time the swelling rate increases and buckling and peeling occurs. The finite element analysis unit 103 is a means (element, functional unit) for performing this analysis. There are no particular limitations on the software used for the analysis, but for example, the finite element method simulation software COMSOL may be used.

[0027] To create an elastic model (physical model) that allows for gradual large deformation of the swellable thin film, an appropriate elastic model is selected for each material. For example, when the swellable thin film is a hydrogel, it is preferable to select a model of an incompressible hyperelastic material (Neo-Hookean model) as the elastic model. The substrate model can be selected taking into account the physical properties of the substrate; for example, a glass material or a rigid body may be selected.

[0028] Boundary conditions are imposed as fixed constraint conditions only on the adhesive region between the substrate and the swellable thin film, while only contact conditions are imposed on the peeling region, according to the pattern set in the peeling region input section 102. This allows for an appropriate representation of buckling peeling on the peeling pattern.

[0029] To describe the swelling (expansion) of a swellable thin film, it is preferable to add the contribution of stress due to the inelastic strain ε=αI (α: swelling ratio, I: unit tensor).

[0030] Inherently, structural dynamics simulations of hyperelastic materials, which take into account the inelastic distortion caused by the swelling of a swellable thin film, are nonlinear simulations involving large deformations. Therefore, simply setting a linear swelling ratio obtained from experimental data and running the simulation results in a problem where the solution does not converge.

[0031] Therefore, the initial swelling ratio of the swellable thin film is set to 1, and the swelling ratio is gradually increased by 0.001 to 0.1 for each step. The solution obtained at each step is used as the initial condition for the next step, and the solution is updated successively. This allows for swelling simulation of swellable thin films such as hydrogels with high swelling ratios of around 1.2 to 1.5.

[0032] (Buckling and peeling shape data storage process) In the buckling peeling shape data storage step, the obtained buckling peeling shape data is stored. The buckling peeling shape data storage unit 104 is a means (element, functional unit) that executes this storage. For a model expanded to the desired linear swelling ratio, the obtained 3D shape is created as a file with an extension such as jpg or png, and can be stored together in any directory on a local PC, or in a database such as SQLite or Postages. At this time, the values ​​set in the peeling region input unit and the swelling thin film parameter input unit may also be stored in a database such as SQLite or Postages.

[0033] As described above, the prediction device and method for buckling and peeling structures of this embodiment allow any peeling pattern to be designed and input simply by obtaining the mechanical properties of the swellable thin film material. Therefore, the three-dimensional shape of any buckling and peeling structure can be predicted without actually fabricating it, which improves the efficiency and reduces the labor required for the prediction.

[0034] Furthermore, the device and method for predicting buckling peeling structures of this embodiment can also make predictions when inputting peeling patterns that are difficult to actually create or material properties that are difficult to realize, which has the potential to lead to new discoveries that cannot be made through experiments.

[0035] Furthermore, in the device and method for predicting buckling and separation structures of this embodiment, by finely adjusting various parameters and using the large amount of 3D shape data obtained, it is possible to comprehensively create phase diagrams for predicting detailed shape changes in buckling and separation structures.

[0036] Furthermore, when predicting a peeling pattern that will generate a desired three-dimensional shape, the large amount of highly accurate three-dimensional shape data obtained by the buckling peeling structure prediction device and prediction method of this embodiment can be used as training data for creating a prediction model using machine learning. [Example]

[0037] The effects of the present invention will be more clearly understood from the following examples. Note that the present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention.

[0038] Example 1 The 3D shape of the buckling peeling structure of a swellable thin film was predicted using the device and method for predicting buckling peeling structures of the above embodiment. Figures 2(a) and 2(b) are a plan view and a cross-sectional view of a structure 10 used in this example. The structure 10 is composed of a solid substrate 11 having one rectangular surface (main surface), an adhesive layer 12 formed in adhesive portion A on one surface of the solid substrate 11, and a swellable thin film 13 formed on one surface of the solid substrate 11 with the adhesive layer 12 sandwiched between them. The area where the adhesive layer 12 is not formed is the peeling portion B.

[0039] A rectangular pattern was set in the peeling region input section, having peeling section B with a length of 6 mm and a width of 800 μm and adhesive sections A on both sides with a length of 6 mm and a width of 300 μm.

[0040] A rigid plate with negligible deformation was set as the solid substrate 11. A hydrogel thin film was set as the swellable thin film 13. In the swellable thin film parameter input section, the following parameters were set for the swellable thin film 13: film thickness: 60 μm, elastic modulus: 218.1 kPa, Poisson's ratio: 0.49, and linear swelling degree: 1.3.

[0041] In the finite element analysis section, the finite element simulation software COMSOL was used, and a hyperelastic material (Neo-Hookean model) and compressibility: nearly incompressible were selected. The initial swelling ratio was set to 1, and the swelling ratio α was parameter-swept in steps of approximately 0.001 to 0.1.

[0042] Figures 3(a) to (c) compare the buckling and peeling structures obtained by changing the swelling degree α. When the swelling degree α was 1.08, a linear type of buckling and peeling structure was observed, in which the thin film on the rectangular pattern bulged out in a semicircular shape. As the swelling degree α increased, it was observed that the structure transitioned to a three-dimensional shape with a meandering shape.

[0043] Example 2 The three-dimensional shape of the buckling peeling structure of a swellable thin film was predicted using the device and method for predicting a buckling peeling structure according to the above embodiment. Figure 4 is a plan view of structure 20 used in this example. In structure 20, one surface (main surface) of a solid substrate has a shape (three-way branching shape) consisting of a central portion 11C and extension portions 11D that branch out and extend in three directions from central portion 11C. That is, one surface of the solid substrate has a shape in which three rectangular patterns are joined at one location. The configuration of one surface of solid substrate 11, other than the shape of the adhesive layer and swellable thin film formed on that surface, is the same as that of structure 10 of Example 1.

[0044] A three-way branching shape pattern was set in the peeling region input section, with peeling section B measuring 6 mm in length and 1000 μm in width and adhesive sections A on both sides measuring 6 mm in length and 300 μm in width.

[0045] A rigid plate with negligible deformation was set as the solid substrate 11. A hydrogel thin film was set as the swellable thin film 13. In the swellable thin film parameter input section, the following parameters were set for the swellable thin film 13: film thickness: 60 μm, elastic modulus: 218.1 kPa, Poisson's ratio: 0.49, and linear swelling degree: 1.3.

[0046] In the finite element analysis section, the finite element simulation software COMSOL was used, and a hyperelastic material (Neo-Hookean model) and compressibility: nearly incompressible were selected. The initial swelling ratio was set to 1, and the swelling ratio α was parameter-swept in steps of approximately 0.001 to 0.1.

[0047] Figure 5 shows the buckling and peeling structure obtained in this example. When the swelling degree α is 1.3 or higher, it is found that the swellable thin film 13B on the peeled portion B of each of the three extension portions 11D swells in a meandering curved shape. It is also found that the three curved portions swell in a complex shape, with the end portions 13C joining each other at the center portion 11C.

[0048] The predicted 3D shape was actually fabricated using the method described in Patent Document 1. First, a pattern similar to that set in the peeling region input section was fabricated by photolithography as a pattern of adhesive functional groups (silane coupling agents) on a glass substrate. Next, a polyacrylamide gel obtained by irradiating acrylamide, methylenebisacrylamide, and the photopolymerization initiator LAP with UV light was synthesized on a glass substrate treated with adhesive functional groups to form a swellable thin film having the physical property values ​​set in the swellable thin film parameter input section.

[0049] Figure 6 shows the state of the resulting polyacrylamide gel thin film / adhesive functional group-treated glass laminate swollen in pure water, observed under a microscope. Figure 6 shows the image obtained from this observation. The hydrogel thin film in the area designated as the peeling region deforms, forming a characteristic three-dimensional shape similar to the predicted result. A three-dimensional shape with a complex morphology in which three curved sections merge, very similar to the predicted three-dimensional shape, is produced. It can be seen that by using the prediction method of the present invention, it is possible to easily output the three-dimensional shape of the complex peeling region in a simulation as a morphology that closely reflects the actual experimental results.

[0050] Example 3 Using the device and method for predicting a buckling peeling structure according to the above embodiment, predictions were made of the three-dimensional shape of a buckling peeling structure of a swellable thin film obtained when the width of the peeling region input section was changed.

[0051] A rectangular pattern was set in the peeling region input section, with peeling section B measuring 6 mm in length and W μm in width, and adhesive section A measuring 6 mm in length and 300 μm on both sides. The width W was set in 100 μm increments in the range of 400 to 1000 μm, and a numerical value corresponding to each width W was output.

[0052] A rigid plate with negligible deformation was used as the solid substrate. A hydrogel thin film was used as the swelling thin film. The swelling thin film parameters were set as follows: film thickness: 60 μm, elastic modulus: 218.1 kPa, Poisson's ratio: 0.49, and linear swelling index: 1.3.

[0053] In the finite element analysis section, the finite element simulation software COMSOL was used, and a hyperelastic material (Neo-Hookean model) and compressibility: nearly incompressible were selected. The initial swelling ratio was set to 1, and the swelling ratio α was parameter-swept in steps of approximately 0.001 to 0.1.

[0054] Figures 7(a) to (f) compare the buckling peel structures obtained by changing the peel width. When α is set to 1.3, the predicted 3D shapes are obtained for each peel width W. When the peel width W is 500 to 600 μm, it can be seen that the thin film changes from a linear rising mode to a meandering rising mode.

[0055] Following Example 2, three-dimensional shapes were created using samples actually fabricated under the same conditions as in the simulation, and the resulting shapes were compared with the predicted three-dimensional shapes. The three-dimensional shapes formed at each peel width were observed using a confocal fluorescence microscope. Figure 8 shows images obtained from this observation. For each peel width, a perspective view of the entire swellable thin film is shown in the upper row, a side cross-sectional view of the rising three-dimensional shape is shown in the middle row, and a plan view (top view) of the three-dimensional shape is shown in the lower row.

[0056] When the peel width was 400 μm, a linear rising mode shape of the swellable thin film was observed, and when the peel width was 500 μm or more, a meandering rising mode shape of the swellable thin film was observed. The predicted 3D shape obtained by using the prediction method of the present invention is a model that closely reflects the actual experimental results, and it shows that it can be easily obtained by inputting the peel area.

[0057] Example 4 Using the device and method for predicting buckling and peeling structures according to the above embodiment, the three-dimensional shapes of the buckling and peeling structures of four samples of swellable thin films were predicted.

[0058] In the peeling region input section, a rectangular pattern was set, following Example 1, having a peeling section with a length of 6 mm and a width of 1 mm and adhesive sections on both sides with a length of 6 mm and a width of 300 μm. A rigid plate with negligible deformation was set as the solid substrate. A hydrogel thin film was set as the swellable thin film. In the swellable thin film parameter input section, the physical property values ​​of the swellable thin film for each sample were set as shown in Table 1 below.

[0059] [Table 1]

[0060] In the finite element analysis section, the finite element simulation software COMSOL was used, and a hyperelastic material (Neo-Hookean model) and compressibility: nearly incompressible were selected. The initial swelling ratio was set to 1, and the swelling ratio α was parameter-swept in steps of approximately 0.001 to 0.1.

[0061] Figures 9(a) to (d) are simulation output diagrams comparing the buckling delamination structures obtained by changing the physical property values, corresponding to samples 1 to 4, respectively. As a result of minutely changing the elastic modulus and linear swelling degree as parameters of the swellable thin film, minute changes were observed in the output predicted 3D shape, and it can be seen that the meandering period and the height of the shape in particular change.

[0062] The predicted three-dimensional shape was actually fabricated using the method described in Patent Document 1. First, adhesive functional group-treated glass was fabricated by photolithography as a pattern of adhesive functional groups (silane coupling agents) on a glass substrate, as in Example 2. Next, a photoresponsive polyisopropylacrylamide gel obtained by dissolving isopropylacrylamide methylenebisacrylamide, a photopolymerization initiator LAP, and gold nanorods in a water / dimethyl sulfoxide mixed solvent and irradiating the solution with UV light was synthesized on the adhesive functional group-treated glass substrate as a swellable thin film having the physical property values ​​set in the swellable thin film parameter input section.

[0063] At this time, the concentration of the cross-linking agent, methylenebisacrylamide, was adjusted to 1 to 4 mol% relative to the monomer in order to reproduce the physical properties corresponding to Samples 1 to 4. By swelling the obtained photoresponsive polyisopropylacrylamide gel thin film / adhesive functional group-treated glass laminate in pure water, the hydrogel thin film on the area designated as the peeling region deformed, forming a characteristic three-dimensional shape.

[0064] Figures 10(a) to (d) show microscope images comparing the buckling and delamination structures obtained by changing the physical properties, corresponding to Samples 1 to 4, respectively. The images of the surface (top) on the swellable thin film side are shown in the upper row, and the images of the opposite surface (bottom) are shown in the lower row. As with the three-dimensional shapes predicted by simulation, it can be seen that the meandering period and the height of the shape change depending on the physical properties.

[0065] Figure 11(a) is a graph showing the relationship between the crosslink density (mol%) of the hydrogel and the height (μm) of the buckling peeling structure, and Figure 11(b) is a graph showing the relationship between the crosslink density (mol%) of the hydrogel and the period (μm) of the shape change of the buckling peeling structure.

[0066] These graphs show that the predicted 3D shapes obtained from simulations and the 3D shape images obtained in actual experiments, when extracted and compared as feature quantities, particularly height and meandering period, show good agreement. These results demonstrate that the prediction method of the present invention can provide highly accurate predicted 3D shape models that reflect shape changes due to detailed physical property values ​​in a simple manner, and is a general-purpose method that can be applied to various types of materials as long as the physical property values ​​are known, regardless of the type of swellable thin film.

[0067] Example 5 Using the device and method for predicting a buckling and peeling structure according to the above embodiment, the three-dimensional shape of a buckling and peeling structure of a swellable thin film was predicted.

[0068] In the peeling region input section, a rectangular pattern was set, following Example 1, having a peeling region with a length of 6 mm and a width of 1 mm and adhesive regions on both sides with a length of 6 mm and a width of 300 μm. A rigid plate with negligible deformation was set as the solid substrate. A hydrogel thin film was set as the swellable thin film. In the swelling thin film parameter input section, the following were set: film thickness: 60 μm, elastic modulus: 113.5 kPa, Poisson's ratio: 0.49, and linear swelling index: 1.32. In addition, an elliptical region with a major axis of 1.2 mm and a minor axis of 1.0 mm was set in the center of the swelling thin film, and the swelling index β of this portion was made independently adjustable.

[0069] In the finite element analysis section, the finite element simulation software COMSOL was used, and a hyperelastic material (Neo-Hookean model) and compressibility: nearly incompressible were selected. The initial swelling ratio was set to 1, and the swelling ratios α and β were subjected to parameter sweeps in steps of approximately 0.001 to 0.1.

[0070] Fig. 12 is a perspective view of the structure used in this example. The swellable thin film 13 formed on the substrate 11 is configured so that the swelling degree β of a portion (here, the central portion) 13D can be controlled independently from the swelling degree α of the other portions.

[0071] Figure 13(a) is a perspective view of the state in which the swellable thin film is buckled and peeled when the swelling degrees α and β are the same. By engraving while the swelling degrees α and β are the same, the swellable thin film is expanded to swelling degrees α and β = 1.32, which reproduces the behavior of the swellable thin film swelling uniformly. As a result, a predicted 3D shape with a meandering shape is output.

[0072] Figure 13(b) shows the change in the swellable thin film when the swelling degree β is reduced from the state in Figure 13(a). By gradually reducing the swelling degree β of the elliptical region in steps of about 0.001 to 0.1, we were able to obtain a model in which the predicted three-dimensional shape locally shrinks.

[0073] To compare this local deformation behavior with an actual experiment, we fabricated a laminate consisting of adhesive functional group-treated glass with a peeling region set in the peeling region input section and a swellable thin film with the physical property values ​​set in the swellable thin film parameters, and performed a comparative study. Figure 14(a) shows an image of the swellable thin film in a state where it is buckled and peeled when the swelling degrees α and β are the same value.

[0074] By preparing a sample following the procedure of Example 4, we were able to obtain a photoresponsive polyisopropylacrylamide gel thin film / adhesive functional group-treated glass laminate with a three-dimensional structure very similar to the predicted three-dimensional shape.

[0075] We confirmed that irradiating the prepared sample with near-infrared laser light collimated into an ellipse with a major axis of 1.2 mm and a minor axis of 1.0 mm locally reduced the swelling of the photoresponsive polyisopropylacrylamide gel thin film, causing it to shrink. Figure 14(b) shows an image of the swellable thin film after irradiating the central region 13C at swelling index β with near-infrared laser light. It can be seen that the region irradiated with near-infrared laser light locally contracted, exhibiting local shrinkage behavior very similar to the predicted three-dimensional shape. These results demonstrate that the prediction method of the present invention can also predict local deformation behavior, indicating its applicability to applications such as analyzing the deformation behavior of stimuli-responsive swellable thin films. [Explanation of symbols]

[0076] 100... Buckling and delamination structure prediction device 101: Peeling area input section 102... Swelling thin film parameter input section 103...Finite element analysis department 104 Buckling and delamination shape data storage section 10...Structure 11...Solid substrate 11C...Central part 11D...Extension part 12...adhesive layer 13, 13A, 13B... Swellable thin film 13C...End 13D: Center of the swelling thin film A...Adhesive part B Peeling area

Claims

1. A device for predicting a buckling and delamination structure formed by peeling off a part of a swellable thin film adhered to one surface of a substrate, comprising: a peeling region input unit for inputting a pattern of a peeling region of the swellable thin film on one surface of the substrate; a swellable thin film parameter input unit for inputting parameters of the swellable thin film required for analysis by the finite element method; a finite element analysis unit that analyzes the resulting buckling and delamination shape of the swellable thin film by the finite element method using the parameters, each time the swelling ratio increases and buckling and delamination occurs; a buckling peeling shape data storage unit that stores the obtained data on the buckling peeling shape.

2. A method for predicting a buckling and delamination structure formed by peeling off a part of a swellable thin film adhered to one surface of a substrate, comprising the steps of: a peeling region input step of inputting a pattern of a peeling region of the swellable thin film on one surface of the substrate; a swellable thin film parameter input step of inputting parameters of the swellable thin film required for analysis by the finite element method; a finite element analysis step of analyzing the resulting buckling and delamination shape of the swellable thin film by the finite element method using the parameters, each time the swelling ratio increases and buckling and delamination occurs; and a buckling peeling shape data storage step of storing the obtained data on the buckling peeling shape.

3. The method for predicting buckling and peeling structures according to claim 2, characterized in that, in the finite element analysis step, the initial swelling ratio of the swellable thin film is set to 1, and the swelling ratio is increased at a rate of 0.001 to 0.1 for each step, and the solution obtained at each step is used as the initial condition for the next step, and the solution is successively updated.

4. The peeled region on the one surface has a rectangular shape, 4. The method for predicting a buckling / peel-off structure according to claim 2, wherein the length of a pair of opposing sides of the rectangle is set to be 100 μm or more and 3000 μm or less.

5. The shape of the peeled region on the one surface is configured to be a shape that is composed of a central portion and extension portions that extend in multiple directions from the central portion, 4. The method for predicting a buckling and peeling structure according to claim 2, wherein the width of the extension is set to be 100 μm or more and 3000 μm or less.

6. 4. The method for predicting a buckling and peeling structure according to claim 2, wherein the width of the adhesive region of the swellable thin film on the one surface is set to 300 μm or more.

7. 4. The method for predicting a buckling and peeling structure according to claim 2, wherein the swellable thin film is made of a material that swells in water or an organic solvent.

8. 4. The method for predicting a buckling and peeling structure according to claim 2, wherein the swelling thin film is made of a material that changes in volume in response to a predetermined stimulus.

Images