Processing method and application of a stimuli-responsive morphing structure

Abstract

This invention discloses a method for fabricating a stimulus-responsive deformable structure, comprising an actuator layer and a passive layer, specifically including the following steps: S1, preparation of the stimulus-responsive deformable structure; S2, microstructure fabrication pattern design; S3, microstructure laser fabrication; S4, application of a stimulus to cause deformation of the structure; its application is a deformable flexible electronic system. This invention, employing the above steps, provides a method for fabricating a stimulus-responsive deformable structure and its application. It uses a laser to directly fabricate micro-damaged structures on a thin film, and quantitatively controls the deformation parameters of the stimulus-responsive deformable structure by adjusting the pattern, depth, width, arrangement direction, and spacing of the micro-damaged structures. This control is precise and rapid, not limited by material fabrication processes, and has a wide range of applications.

Description

Technical Field

[0001] This invention relates to the field of stimulus-responsive deformable structure fabrication technology, and in particular to a processing method and application of a stimulus-responsive deformable structure. Background Technology

[0002] Stimulus-responsive deformable structures deform when subjected to specific external stimuli (including light, temperature, humidity, pH, magnetic field, and electricity), transforming from a planar two-dimensional thin film structure into a three-dimensional structure. Integrating electronic devices or other functional components onto the stimulus-responsive deformable thin film structure allows for the convenient introduction of mature planar microelectronic fabrication processes into the three-dimensional structure, enabling the functional components to be conformally self-mounted and self-fixed on the target in three dimensions.

[0003] In stimulus-responsive deformable thin film structures, parameters such as the direction and curvature of deformation are typically controlled by adjusting the film thickness, degree of crosslinking, elastic modulus, or by combining different material components on a plane. However, these methods involve complex, difficult, or time-consuming processes, and most of the adjustable parameters involve inherent material properties, requiring control during material preparation, which greatly limits the flexibility and convenience of control. Furthermore, existing methods cannot control deformation over time, limiting their application in complex deformable structures. Due to limitations in processing methods, these methods have poor compatibility with planar microelectronic integration fabrication processes, restricting their application in intelligent deformable flexible electronic systems. Summary of the Invention

[0004] The purpose of this invention is to provide a method for processing stimulus-responsive deformable structures and its application. The method uses a laser to directly process micro-damaged structures on a thin film, and quantitatively controls the deformation parameters of the stimulus-responsive deformable structure by adjusting the pattern, depth, width, arrangement direction, and spacing of the micro-damaged structures. The control is precise and rapid, not limited by the material preparation process, and has a wide range of applications.

[0005] To achieve the above objectives, the present invention provides a method for processing a stimulus-responsive deformable structure. The stimulus-responsive deformable structure includes an actuating layer and a passive layer. The actuating layer is a single-layer or multi-layer structure that deforms when subjected to a specific stimulus. The passive layer is a single-layer or multi-layer structure that does not respond to the stimulus or has a different response than the material of the actuating layer. The actuating layer and the passive layer are bonded together by a strong interface. When subjected to a specific stimulus, a strain difference is generated between the actuating layer and the passive layer, thereby causing deformation from two dimensions to three dimensions.

[0006] Specifically, the following steps are included:

[0007] S1. Preparation of stimulus-responsive deformable structures

[0008] A thin film containing an actuator layer and a passive layer with a stimulus-responsive deformation structure was prepared by a fabrication process.

[0009] S2, Microstructure fabrication graphic design

[0010] Based on the correspondence between the direction, depth, width, and spacing of the laser-processed micro-damaged structure and the deformation parameters, as well as the required three-dimensional structure, a drawing of the microstructure is designed. Deformation parameters include deformation direction, bending curvature, and actuation time. The classical thermal expansion bending equation for bimetallic beams is used.

[0011]

[0012] The deformation curvature of this stimulus-responsive deformation structure is related to the difference in expansion of the bilayer membrane, the ratio of elastic moduli, and the ratio of thickness.

[0013] S3, Microstructure laser processing

[0014] Import the drawings and use a laser beam to fabricate micro-damaged structures on the stimulus-response deformable structure, such as... Figure 1 As shown. Based on the mechanism of interaction between the laser beam and the material, laser processing can be broadly divided into two categories: laser thermal processing and photochemical reaction processing. Laser thermal processing refers to the processing process that utilizes the thermal effect generated by the laser beam projected onto the material surface; photochemical reaction processing refers to the processing process in which the laser beam irradiates the object, and the high-density laser high-energy photons initiate or control a photochemical reaction.

[0015] The width and depth of a single micro-damage structure can be adjusted by regulating parameters such as laser power, scanning speed, and number of scans. The arrangement direction and spacing of the micro-damage structures can be adjusted by designing the drawings.

[0016] S4. Applying stimuli to cause structural deformation.

[0017] Applying a stimulus to the thin film structure that corresponds to the stimulus-responsive material used causes the thin film to respond and undergo the desired three-dimensional shape transformation.

[0018] Preferably, the preparation process described in S1 includes, but is not limited to, spin coating, blade coating, mold casting, sol-gel, irradiation polymerization, sputtering, vapor deposition, and chemical deposition.

[0019] The materials of the actuation layer and the passive layer are not limited to homogeneous materials.

[0020] An application of a stimulus-responsive deformable structure fabrication method is disclosed. The application is a deformable flexible electronic system, which includes an actuating layer and a passive layer. The surface of the actuating layer has a micro-damage structure fabricated by a laser beam. The passive layer, on the side away from the actuating layer, integrates electronic devices using a two-dimensional planar microelectronic fabrication process.

[0021] Therefore, the processing method and application of the stimulus-responsive deformation structure using the above steps of the present invention have the following beneficial effects:

[0022] 1. The laser processing technology used can easily control the cross-sectional shape, size, direction, and directional arrangement spacing of the micro-damage structure by adjusting parameters such as laser power, scanning speed, and number of scans, as well as the design of the micro-damage pattern. This allows for precise quantitative control of the deformation parameters of the stimulus-response structure, including deformation direction, bending curvature, and actuation time.

[0023] 2. The processing is simple and fast, and the micro-damage pattern can usually be processed in just a few seconds to a few minutes;

[0024] 3. Laser processing technology can be used to fabricate microstructures on the surface of stimulus-responsive materials, endowing them with special processing properties without altering their intrinsic properties, making control more flexible and convenient. When the multilayer films in a stimulus-responsive structure are all uniform films, complex deformation actions can be achieved by simultaneously forming microstructure patterns with different line depths, widths, and arrangements on the same film sample.

[0025] 4. The method for controlling the deformation parameters of the stimulus-response deformable structure through laser processing of microstructures is applicable to various types of stimulus-response deformable materials that can be damaged by lasers, and is not limited by the material preparation process, thus having a wide range of applications.

[0026] 5. The laser processing technology used in this invention can selectively process target materials according to different laser wavelengths. For example, it can process lower materials through upper materials, providing greater flexibility and freedom for the entire fabrication process design of the device.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the microstructure laser processing state of the processing method and application of the stimulus-responsive deformation structure of the present invention.

[0029] Figure 2 This is an image showing the effect of a single micro-damage structure processed on the surface of a PVA film using a laser in Embodiment 1 of the present invention;

[0030] Figure 3 This is an image showing the effect of line marks with different widths and depths formed by changing laser processing parameters in Embodiment 1 of the present invention.

[0031] Figure 4 This is a graph showing the effect of line spacing on curvature and actuation time in Embodiment 1 of the present invention.

[0032] Figure 5 This is a diagram illustrating the effect of the line marking arrangement direction on the deformation direction in Embodiment 1 of the present invention.

[0033] Figure 6 This is a diagram of the conical spiral structure formed by micro-damage structure control design in Embodiment 1 of the present invention;

[0034] Figure 7 This is a rendering of the bow structure formed by micro-damage structure control design in Embodiment 1 of the present invention;

[0035] Figure 8 This is an illustration of the effect of the self-locking structure formed by micro-damage structure control design in Embodiment 1 of the present invention;

[0036] Figure 9 This is a diagram illustrating the self-fixing effect of the spiral structure self-deformable electrode on the target in Embodiment 2 of the present invention.

[0037] Figure 10 This is a curve showing the effect of line mark depth on curvature in Embodiment 3 of the present invention.

[0038] Figure 11 This is a curve showing the effect of line spacing on curvature in Embodiment 3 of the present invention.

[0039] Figure 12 This is a diagram illustrating the effect of the line marking arrangement direction on the deformation direction in Embodiment 3 of the present invention.

[0040] Figure Labels

[0041] 1. Laser; 2. Laser beam; 3. Actuation layer; 4. Passive layer; 5. Micro-damage structure. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] Example 1: Laser-controlled generation of a PVA / PCL bilayer water-responsive mechanical deformation system

[0044] S1. Preparation of stimulus-responsive deformable structures

[0045] A PCL solution (dissolved in N,N-dimethylformamide at a mass fraction of 20 wt.%) was spin-coated onto a clean glass slide, and then dried at 80°C for 5 minutes to remove the solvent, resulting in a PCL film as the passive layer 4 of the stimulus-responsive deformation structure. Then, using a custom-made mold, the mold was placed on the PCL film surface, and a certain mass of 10% PVA aqueous solution was poured onto the PCL film surface in the mold. After drying at 80°C for 2 hours to remove the solvent, the resulting PVA film exhibited the characteristic of large swelling deformation in humid environments or in water, serving as the actuating layer 3 of the stimulus-responsive deformation structure.

[0046] S2, Microstructure fabrication graphic design

[0047] Based on the correspondence between the direction, depth, width, and spacing of the laser-processed micro-damaged structure 5 and the deformation parameters, as well as the required three-dimensional structure, a drawing of the microstructure is designed. The deformation parameters include the deformation direction, bending curvature, and actuation time. The principle of controlling the deformation of the micro-damaged structure 5 by processing it on a stimulus-responsive deformable material is that the bending stiffness at the traced area decreases due to the reduction in the moment of inertia of the cross section, causing the structure to undergo directional deformation. Increasing the trace depth and decreasing the trace spacing will both lead to an increase in the reduction of bending stiffness, thereby reducing the driving force required for structural bending, increasing the actuation speed, and ultimately increasing the curvature.

[0048] S3, Microstructure laser processing

[0049] Micro-damaged structures 5 were fabricated on the PVA surface using a laser beam 2 emitted from laser 1, and then tested. The width and depth of individual line marks were adjusted by regulating parameters such as laser power, scanning speed, and number of scans. The arrangement direction and spacing of the line marks were adjusted according to the design drawings.

[0050] Figure 2 The image shows a cross-section of a single micro-damaged structure 5 machined on a PVA surface, with the single line mark having a V-shaped cross-section. Figure 3 The diagram shows cross-sections of damage structures of different depths and widths obtained by adjusting laser parameters, including power, scanning speed, number of scans, and duty cycle. The depth can range from tens of nanometers to cutting through the thin film, or it can form a groove with a certain width and inclined walls by multiple lines closely arranged. Figure 3 The depth of the micro-damage structure 5 in parts a, c, and e is 40 μm. Figure 3 The depth of the micro-damage structure 5 in b, d, and f is 100 μm.

[0051] Figure 4The correlation between the directional spacing of the micro-damage structure 5 in the PVA / PCL stimulus-responsive deformation structure and the curvature and actuation time of the deformation is shown. This correlation allows for precise quantitative control of the curvature and actuation time of the deformation by adjusting the spacing of the line marks.

[0052] Figure 5 The diagram illustrates the precise control of the deformation direction by the arrangement of the five micro-damaged structures. The inset at the bottom left of each figure shows its laser-processed drawing, within a 3mm radius. Micro-damaged structures 5 with different alignment directions were fabricated on a 30mm thick PVA / PCL bilayer rectangular strip film sample. The tilt angles θ of the micro-damaged structures 5 from left to right are θ=75°, θ=60°, θ=45°, θ=30°, and θ=15°. When the sample responds to humidity stimulation, it will bend around the direction of the line marks to form cylindrical helical structures with different pitches.

[0053] Figure 6 The diagram shows a conical spiral structure formed by controlling the micro-damage structure 5 using laser processing. The inset in the lower left corner of each figure is the laser processing drawing. The left figure shows a conical spiral structure with a gradually increasing spiral radius formed by the gradually increasing spacing of the lines from top to bottom of the PVA / PCL rectangular strip. The right figure shows a spiral structure with a gradually increasing spiral radius formed by the first increasing and then decreasing spacing of the lines from top to bottom of the rectangular strip.

[0054] Figure 7 The diagram shows a bow structure formed by laser processing of micro-damage structure 5 in a PVA / PCL stimulus-responsive bilayer structure. The lower left illustration shows the laser processing drawing. By adjusting the direction and spacing of the lines in each area, the left and right wings and two spiral bands of the bow are first deformed and formed, and finally the upper rectangular bend is used to fix the shape.

[0055] Figure 8 The diagram illustrates a self-locking structure formed by controlling the micro-damage structure 5 through laser processing. The lower left inset shows the laser processing drawing. By adjusting the arrangement and spacing of the lines in each region, when the structure undergoes stimulus-response deformation, the T-shaped structure on one side of the rectangle bends upwards first, while the two "doors" on the other side bend inwards. Then, as the entire rectangular structure bends, the T-shaped structure engages with the "doors" on the other side, completing the self-locking process. This self-locking structure can maintain the shape of the double-layer structure at the bend and provides a certain degree of constraint.

[0056] S4. Applying stimuli to cause structural deformation.

[0057] The film structure responds to stimuli corresponding to the stimulus-responsive material used, causing the film to make a corresponding response and undergo a three-dimensional shape transformation designed by S3.

[0058] Example 2: Self-deforming flexible electrode

[0059] After the PVA / PCL stimulus-responsive deformable bilayer structure in Example 1 was fabricated, a Ni / Au electrode was sputtered onto the PCL layer surface using magnetron sputtering. A mask was used to pattern the electrode, resulting in a stimulus-responsive self-deforming flexible electrode. When subjected to a certain level of humidity stimulation, the PVA / PCL film can support the electrode and cause the desired deformation. Figure 9 As shown, when an electrode is sputtered onto a thin film that is intended to have a spiral structure, the resulting self-deformable electrode automatically wraps around the target when stimulated by humidity, forming a strong and conformal connection interface without the need for additional fixation.

[0060] Example 3: Laser-controlled CNT-PDMS / PDMS / PI three-layer photothermal responsive mechanical deformation system

[0061] S1. Preparation of stimulus-responsive deformable structures

[0062] A smooth PI film was prepared by bonding a layer of PDMS adhesive to a clean glass slide, then coating a layer of PDMS onto the PI film and curing it at 80°C. Next, a layer of CNT-PDMS was coated onto the cured PDMS and cured at 80°C, resulting in a three-layer photothermal responsive mechanical deformation system of CNT-PDMS / PDMS / PI. The carbon nanotubes in the CNT-PDMS layer undergo photothermal conversion upon light irradiation, transferring heat to the other two layers. The CNT-PDMS and PDMS layers have high coefficients of thermal expansion and serve as the active layers in the deformation structure, while the PI layer has a low coefficient of thermal expansion and serves as the passive layer.

[0063] S2, Microstructure fabrication graphic design

[0064] Based on the correspondence between the direction, depth, width, and spacing of the laser-processed micro-damaged structure 5 and the deformation parameters, as well as the required three-dimensional structure, a drawing of the microstructure is designed. The deformation parameters include the deformation direction, bending curvature, and actuation time.

[0065] S3, Microstructure laser processing

[0066] The micro-damage structure 5 is fabricated on the surface of the active layer using laser beam 2. Figure 10 and Figure 11 The study demonstrates the correspondence between the depth of the filaments and the spacing of the filament orientation in the CNT-PDMS / PDMS / PI stimulus-responsive deformation structure and the curvature of the deformation. This correspondence allows for precise quantitative control of the curvature of the deformation by adjusting the filament depth or the spacing of the filament orientation.

[0067] Figure 12The precise control of the deformation direction by the alignment of the line marks was demonstrated. Micro-damage structures with different alignment directions were fabricated on a CNT-PDMS / PDMS / PI three-layer rectangular strip film sample. When the sample is subjected to thermal stimulation, it will bend around the direction of the line marks to form a cylindrical spiral structure with different pitches.

[0068] S4. Applying stimuli to cause structural deformation.

[0069] The film structure responds to stimuli corresponding to the stimulus-responsive material used, causing the film to make a corresponding response and undergo a three-dimensional shape transformation designed by S3.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for processing a stimulus-responsive deformable structure, characterized in that: The stimulus-response deformable structure includes an actuating layer and a passive layer. The actuating layer is a single-layer or multi-layer structure that deforms when stimulated by light, temperature or humidity. The passive layer is a single-layer or multi-layer structure that does not respond to light, temperature or humidity or whose response is different from that of the actuating layer material. The actuating layer and the passive layer are bonded together by a strong interface. When stimulated by light, temperature or humidity, a strain difference is generated between the actuating layer and the passive layer, resulting in deformation from two-dimensional to three-dimensional. Specifically, the following steps are included: S1. Preparation of stimulus-responsive deformable structures A stimulus-responsive deformation structure thin film containing an actuator layer and a passive layer was prepared using a fabrication process. S2, Microstructure fabrication graphic design Based on the correspondence between the pattern, direction, depth, width, and spacing of the laser-processed micro-damaged structure and the deformation parameters, as well as the required three-dimensional structure, design the drawings of the micro-structure to be processed. The deformation parameters include the deformation direction, bending curvature, and actuation time. S3, Microstructure laser processing Import the drawings and use a laser beam to process micro-damage structures on the actuation or passive layer of the stimulus-response deformation structure. The width and depth of a single micro-damage structure can be adjusted by adjusting the parameters of laser power, scanning speed and number of scans. The arrangement direction of the micro-damage structures and the spacing between micro-damages can be adjusted according to the design of the drawings. S4. Applying stimuli to cause structural deformation. Apply light, temperature, or humidity stimulation to the thin film structure in accordance with the stimulus-responsive material used, so that the thin film responds and undergoes the required three-dimensional shape transformation. One application of a stimulus-responsive deformable structure fabrication method is a deformable flexible electronic system. The deformable flexible electronic system includes an actuating layer and a passive layer. The surface of the actuating layer has a micro-damage structure fabricated by a laser beam. The side of the passive layer away from the actuating layer is used to integrate electronic devices using a two-dimensional planar microelectronic fabrication process.

2. The processing method of a stimulus-responsive deformable structure as described in claim 1, characterized in that: The preparation process described in S1 includes spin coating, blade coating, mold casting, sol-gel, irradiation polymerization, sputtering, vapor deposition, and chemical deposition.

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