Flexible stretchable electronic device and preparation method and application thereof based on laser surface treatment

Abstract

The invention belongs to the related technical field of flexible electronic devices, and discloses a flexible stretchable electronic device and a preparation method and application thereof based on laser surface treatment.The method comprises the following steps that firstly, arrangement patterns of micro-grooves are set according to performance requirements of the flexible stretchable electronic device to be prepared; secondly, the surface of the substrate is ablated through picosecond ultraviolet laser to form the micro-gullies, and the geometrical characteristics of the micro-gullies are adjusted by adjusting parameters of the picosecond ultraviolet laser; step 3, sputtering a functional layer on the surface of the micro-gully; and 4, macroscopically patterning the functional layer to obtain the flexible stretchable electronic device. The method is simple in technological process, suitable for various elastic-plastic substrates, suitable for various functional materials and convenient to use in a large area, can be combined with other macrostructure / material design, and meanwhile is suitable for further enhancing performance.

Description

Technical Field

[0001] The present invention belongs to the technical field related to flexible electronic devices, and more specifically, relates to a flexible stretchable electronic device and a preparation method and application thereof based on laser surface treatment. Background Art

[0002] In extreme environments, due to the different material properties of various components of aerospace equipment, under the influence of complex working environments or loads such as strong radiation, high and low temperatures, strong impact, high speed, and high pressure, large deformation or non-uniform deformation will occur, such as variant aircraft or space parachutes. This requires sensors to be able to withstand / measure large tensile (bending) deformations of flexible components in equipment, and to accurately measure small deformations of rigid components. Existing sensors are difficult to take into account both wide measurement range and high measurement sensitivity. Therefore, it is necessary to develop flexible and stretchable electronic devices with "programmable" (i.e., tensile performance partitioning) and "large area" characteristics to achieve customized performance design of sensors in different observation areas. Therefore, the use of flexible and stretchable sensors to accurately measure key parameters such as tension, compression, bending, and torsion deformation of equipment provides new ideas for obtaining the overall deformation state information of aerospace equipment, and is of great significance for its structural design optimization and real-time control.

[0003] Flexible smart skins are usually composed of stretchable electronic devices, including various stretchable electronic devices such as bionic epidermal electronics and implantable electronic devices. They have high stability, high conductivity under high strain (>100%), and process compatibility with the active layer. They can achieve elastic stretchability, conformal attachment and wrapping of any complex surface, and maintain stable electrical properties.

[0004] Therefore, it is widely used in health monitoring, rehabilitation medicine, smart industry, aerospace and other fields. Traditional strain measurement methods include resistance strain gauges, optical strain gauges, digital speckle, etc., which have problems such as insufficient range, interference with drawing processing, and visual blind spots, and are difficult to meet the needs of skin drawing process. Among them, the specific performance parameters of existing electronic devices are shown in Table 1:

[0005] Table 1 Performance parameters of sensing materials and their corresponding electronic devices

[0006]

[0007] Traditional stretchable electronics such as stretchable conductive inks, Patent No. 202410027827.5 proposes a method for preparing stretchable graphene conductive inks and directly printing graphene conductive inks on substrate fabrics to prepare flexible graphene electric heating films. Elastomer fiber and silver nanoparticle composite nonwoven mat, Patent No. 202210789440.4 discloses a method for preparing a stretchable electromagnetic shielding elastic material using an elastomeric polymer containing fibrous carbon fillers as a substrate and embedding silver nanoparticles on its surface and interior. Designing original microcracks on flexible electronics, Patent No. 202111281420.8 proposes a method for preparing a flexible electrode by treating the surface of a polymer substrate with a reactive ion etching method and then forming a gold film with a nanoscale microcrack structure by magnetron sputtering deposition, etc., which has one or more of the following disadvantages: 1) The objectivity is too strong, and the stretching direction is limited due to the limitations of the material. 2) Poor performance stability, durability, and dynamic performance: cannot be reused or fatigue and damage occur after repeated stretching and bending, and the conductivity performance will change. 3) Difficult to integrate, complex manufacturing, and difficult to apply on a large scale. 4) Crack penetration / crack extension is uncontrollable, highly random, and inconsistent. Summary of the invention

[0008] In view of the above defects or improvement needs of the prior art, the present invention provides a flexible stretchable electronic device and a preparation method and application thereof based on laser surface treatment, which aims to solve the problems that the existing preparation process is too object-oriented and the manufacturing process is cumbersome and complicated.

[0009] To achieve the above object, according to one aspect of the present invention, a method for preparing a flexible and stretchable electronic device based on laser surface treatment is provided, the method comprising the following steps:

[0010] Step 1, setting the arrangement pattern of micro-grooves according to the performance requirements of the flexible and stretchable electronic device to be prepared;

[0011] Step 2, using picosecond ultraviolet laser to ablate the substrate surface to form the micro-grooves, wherein the geometric features of the micro-grooves are adjusted by adjusting the picosecond ultraviolet laser parameters;

[0012] Step 3, sputtering a functional layer on the surface of the micro-grooves;

[0013] Step 4: macroscopically patterning the functional layer to obtain a flexible and stretchable electronic device.

[0014] Furthermore, the arrangement patterns include paper-cut, snake, rectangle, fractal, dot matrix, island-bridge and Ferris wheel shapes.

[0015] Furthermore, by adjusting the laser processing parameters and scanning different processing parameters at different points and different areas of the substrate, programmable stretching performance can be achieved.

[0016] Furthermore, the material of the substrate is a superelastic material polydimethylsiloxane or polyimide.

[0017] Furthermore, the laser power used in the picosecond ultraviolet laser ablation is 10%, the processing speed is 1000 mm / s, the repetition frequency is 200 times, and the filling interval is 10 μm.

[0018] Furthermore, the depth of the surface micro-grooves is 1.7 μm; and the functional layer is a 200-nanometer-thick Constantan alloy layer.

[0019] Furthermore, the laser power used in the picosecond ultraviolet laser ablation is 50%, the processing speed is 1000 mm / s, the repetition frequency is 200 times, and the filling interval is 20 μm.

[0020] Furthermore, the functional layer is a 100-nanometer-thick Au / Cr alloy layer; the depth of the surface micro-grooves is 4.3 μm.

[0021] The present invention also provides a flexible stretchable electronic device, which is prepared by the flexible stretchable electronic device preparation method based on laser surface treatment as described above.

[0022] The present invention also provides an application of the flexible and stretchable electronic device as described above in health monitoring, rehabilitation medicine, smart industry and aerospace.

[0023] In general, compared with the prior art, the flexible stretchable electronic device and its preparation method and application based on laser surface treatment provided by the present invention mainly have the following beneficial effects:

[0024] 1. The preparation method has a simple process flow, is applicable to various elastic-plastic substrates, is applicable to various functional materials, is convenient for large-area use, can be combined with other macrostructure / material designs, and is applicable to further enhance performance.

[0025] 2. By selecting different laser processing parameters for surface treatment to control the geometric characteristics of the groove microstructure, the crack propagation is controlled by the obtained grooved microstructure to adjust the tensile properties; the programmable characteristics of the laser are used to achieve single-point adjustable performance, partitioned performance adjustment, controllable tensile performance partitions, and customized composite tensile properties of the material surface (such as inability to stretch - biaxial stretching - strain sensitivity).

[0026] 3. By selecting different laser parameters (mainly laser power, processing speed, and processing frequency), the substrate surface is ablated to form micro-grooves (depth-interval) with different geometric parameters. Micro-grooves with different geometric parameters correspond to different tensile properties. By combining the design of the groove arrangement pattern, the tensile performance zoning can be controlled - the composite tensile properties of the material surface (such as inability to stretch - biaxial stretching - strain sensitivity) are customized to achieve single-point performance adjustment and overall performance zoning; at the same time, it has the characteristics of wide measurement range and high measurement sensitivity.

[0027] 4. The cross crack blocking mechanism is adopted, and a groove-like microstructure is formed through laser treatment to inhibit crack extension, control the direction of crack extension, and improve the tensile properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a pattern processed by unidirectional laser;

[0029] Figure 2 Multi-directional laser processed patterns;

[0030] Figure 3 is a schematic diagram of the cross section after laser treatment;

[0031] Figure 4 is a schematic cross-sectional view after metal deposition;

[0032] Figure 5 is a schematic diagram of unidirectional stretchable electronically suppressed crack propagation;

[0033] Figure 6 is a schematic diagram of multi-directional stretchable electronically suppressed crack propagation;

[0034] Figure 7 is a schematic diagram of the crack extension without treatment;

[0035] Figure 8 The process effect schematic diagram and SEM diagram are respectively a control diagram, a schematic diagram after paper cutting treatment, a schematic diagram of treatment in parallel to the stretching direction, and a schematic diagram of treatment in perpendicular to the stretching direction;

[0036] Fig. 9 1 is a schematic diagram of the effect of laser parameters and groove spacing on tensile properties, and 2 is a schematic diagram of the effect of different laser powers, processing speeds and groove spacing on tensile properties;

[0037] Fig.10 Schematic diagram of the influence of different parameters (laser power, gully distance, laser frequency, processing speed) on the gully geometric parameters. Schematic diagram of the influence of different laser power, gully distance, laser frequency and processing speed on the gully geometric parameters. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Due to the huge differences in the material properties of various components of aerospace equipment, non-uniform deformation is prone to occur in complex working environments or loads. The large deformation of flexible components and the small deformation of rigid components need to be accurately measured. The commonly used functional materials in existing flexible stretchable electronic devices will inevitably have many cracks during the stretching process, which seriously affects their performance, and it is difficult to take into account both wide measurement range and high measurement sensitivity. The present invention proposes a stretchable electronic manufacturing method based on laser programmable surface treatment, develops flexible stretchable electronic devices with "programmable" and "large area" characteristics, studies the influence of different substrates, functional materials, laser parameters, and filling patterns on the geometric parameters of gully microstructures, and the influence mechanism of the "gully" microstructure formed by laser scanning on the surface of the flexible substrate on the crack extension of the functional material, effectively customizes its stretchable strain, and realizes the controllable single-point stretching performance of the flexible stretchable device and the adjustable overall partition. The use of stretchable flexible electronic devices can accurately measure and obtain the key parameters of the equipment, effectively obtain the deformation state information of aerospace equipment, and is of great significance to the optimization and real-time control of equipment structure design.

[0040] The present invention provides a preparation method of a flexible stretchable electronic device based on laser surface treatment, the preparation method utilizes picosecond ultraviolet laser processing, utilizes different laser processing parameters to ablate the surface of a substrate to form micro-grooves, utilizes laser ablation to form micro-grooves with different geometric parameters according to the regular effect of the geometric parameters (depth, spacing) of the grooves on the tensile properties, and controls the laser processing parameters to scan on the substrate to form micro-grooves with a specifically designed micro-groove arrangement pattern and specific size parameters, controls crack propagation through the micro-grooves, and regulates the tensile properties, after patterning, deposits a metal film on the surface of the patterned substrate through magnetron sputtering, and then removes excess metal through laser, thereby achieving single-point adjustable performance and programmable effects of overall performance partitioning, the process substrate has universality, and can be combined with other macroscopic structure / material designs to further improve the tensile properties.

[0041] In one embodiment, the preparation method effectively utilizes the long longitudinal grooves produced by the growth of tree rings and the orientation of wood fibers, which can effectively block the bionic principle of transverse cracks caused by the growth of trees, and uses laser ablation to form micro-grooves on the surface of the substrate to inhibit crack propagation; and thereby inspires the design of patterns that effectively inhibit cracks / control the direction of crack extension in multiple stretching directions.

[0042] The preparation method mainly comprises the following steps:

[0043] Step 1: Set the arrangement pattern of microgrooves according to the performance requirements of the flexible and stretchable electronic device to be prepared.

[0044] By designing different micro-groove arrangement patterns, the stretching performance in different stretching directions can be improved. By utilizing the programmable effect of lasers and designing the micro-groove arrangement pattern, a pattern of stretching performance partitioning (such as unidirectional stretching-tensile resistance-sensitive-bidirectional stretching) can be designed on the substrate, so that the stretching performance can be edited at a single point and the whole can be partitioned.

[0045] The arrangement patterns of micro-grooves can be divided into: unidirectional stretching (rectangle, etc.), bidirectional stretching (paper-cut, etc.), and multi-directional stretching (snake, fractal, dot matrix, island-bridge, Ferris wheel, etc.).

[0046] Step 2: Using picosecond ultraviolet laser to ablate the substrate surface to form the micro-grooves, wherein the geometric features of the micro-grooves are adjusted by adjusting the picosecond ultraviolet laser parameters.

[0047] The laser processing parameters have a regular effect on the tensile properties. By quantitatively adjusting different laser parameters to perform ablation forming on the substrate surface to generate micro-grooves with different geometric parameters, different tensile properties (large strain, high sensitivity, non-stretchable, unidirectional stretching, multi-directional stretching) can be achieved.

[0048] Micro-grooves with different geometric parameters formed by different laser processing parameters have a regular effect on the tensile properties. By adjusting the laser processing parameters and scanning different processing parameters at different points and different areas of the substrate, the effect of programmable tensile properties can be achieved.

[0049] In one embodiment, according to the arrangement pattern (paper-cut, serpentine, rectangular, fractal, dot matrix, island-bridge, Ferris wheel shape), the substrate surface is scanned by a picosecond ultraviolet laser, and the surface micro-grooves are formed by processing with the required laser parameters (for example, laser power: 50%, processing speed: 1000mm / s, repetition frequency: 200times) to form micro-grooves with the required geometric parameters (depth 4μm, spacing 20μm).

[0050] The functional material is deposited on the surface of the substrate after laser treatment in step 1 by magnetron sputtering to form an alloy-substrate composite film with a groove shape.

[0051] The geometric parameters of the micro-grooves are micro-depth of about 4.3μm and spacing of 20μm. The tensile strain range is large, the strain coefficient is high, and the comprehensive performance is good.

[0052] Step three, sputtering a functional layer on the surface of the micro-grooves.

[0053] Step 4: macroscopically patterning the functional layer to obtain a flexible and stretchable electronic device.

[0054] In another embodiment, the composite film obtained in step 2 is patterned by using a picosecond ultraviolet laser with the required laser parameters (e.g., laser power: 50%, processing speed: 1000 mm / s, repetition frequency: 200 times, filling interval: 20 μm) to remove excess metal around it and customize the stretching ability of the flexible electronic device, such as suppressing the penetration and propagation of cracks during the stretching process through surface micro-grooves, thereby improving the fracture strain limit of the functional material.

[0055] After processing using this technology, it can be combined with macro structures such as snake-shaped and paper-cut shapes and materials such as fibers and graphene to further enhance performance.

[0056] Micro-grooves controlling crack propagation are effective on different elastic-plastic substrates and different functional materials, the tensile properties are controllable, and large-area manufacturing is possible.

[0057] The present invention also provides a flexible stretchable electronic device, which is prepared by the flexible stretchable electronic device preparation method based on laser surface treatment as described above.

[0058] The present invention also provides an application of the flexible and stretchable electronic device as described above in health monitoring, rehabilitation medicine, smart industry and aerospace.

[0059] The present invention is further described in detail below with reference to specific embodiments.

[0060] Example 1, Unidirectional Stretchable Electronic Device

[0061] (1) Based on Figure 1 The pattern was formed by scanning the polyimide (PI) surface with a picosecond UV laser, with a laser power of 10%, a processing speed of 1000 mm / s, a repetition frequency of 200 times, and a filling interval of 10 μm. The depth of the surface micro-grooves was 1.7 μm. Figure 3 shown.

[0062] (2) depositing 200 nanometers of constantan alloy on the surface of the substrate treated by laser in step 1 by magnetron sputtering to form a constantan alloy-PI composite film with a gully shape, such as Figure 4 shown.

[0063] (3) Patterning the composite film obtained in step (2) with a picosecond ultraviolet laser at a laser power of 10%, a processing speed of 1000 mm / s, a repetition frequency of 200 times, and a filling interval of 10 μm, removing excess metal around the composite film to obtain a flexible skin with unidirectional stretchability, such as Figure 5 As shown. Figure 7 The flexible and stretchable electronic device shown in the figure has no laser surface treatment. In this example, the transverse surface micro-grooves are used to suppress the through-propagation of longitudinal cracks during transverse stretching, thereby improving the transverse fracture strain limit of Constantan alloy.

[0064] Example 2: Multidirectional stretchable electronic device

[0065] (1) The substrate is made of polydimethylsiloxane (PDMS), and the ratio of curing agent to PDMS is 1:10. The mixture is stirred thoroughly and vacuum is used to eliminate bubbles.

[0066] (2) Using a coating machine, Teflon was first spin-coated on a glass sheet in multiple steps. The first step was to spin-coat at a speed of 500 rad for 6 s, with an acceleration of 500 rad / s. The second step was to spin-coat at a speed of 2000 rad for 60 s, and then cured at 100° C. for 30 min. The PDMS prepared in step (1) was spin-coated on the cured Teflon. The first step was to spin-coat at a speed of 100 rad for 5 s, with an acceleration of 100 rad / s. The second step was to spin-coat at a speed of 300 rad for 30 s, and then cured at 60° C. for 120 min.

[0067] (3) Based on Figure 2 The pattern was formed by scanning the polydimethylsiloxane (PDMS) surface with a picosecond UV laser, with the parameters of laser power: 50%, processing speed: 1000 mm / s, repetition frequency: 200 times, and filling interval: 20 μm, and the depth of the surface micro-grooves was 4.3 μm. Figure 3 shown.

[0068] (4) depositing 100 nanometers of Au / Cr alloy on the surface of the substrate treated by laser in step (1) by magnetron sputtering to form an Au / Cr alloy-PDMS composite film with a groove shape, such as Figure 4 shown.

[0069] (5) Patterning the composite film obtained in step (2) with picosecond ultraviolet laser at the parameters of laser power: 50%, processing speed: 1000 mm / s, repetition frequency: 200 times, and filling interval: 20 μm, removing the surrounding excess metal to obtain a flexible skin with multi-directional stretching ability, such as Figure 6 As shown. Figure 7The flexible electronic device shown in the figure has no laser surface treatment. In this example, the surface micro-grooves of the staggered paper-cuts in two directions suppress the penetration and propagation of cracks during multi-directional stretching, thereby improving the multi-directional fracture strain limit of the Au / Cr alloy.

[0070] (6) Peel PDMS off Teflon to get the product. The stretchable smart skin made of PDMS can be adjusted within the strain range of 2%-52% and the sensitivity within 2-1800 by adjusting the laser parameters and the arrangement pattern of the gullies. Combined with other macrostructure / material designs, such as serpentine Fig. 9 , which can further improve the tensile properties and increase the strain to 140%.

[0071] in, Figure 8 The process effect schematic diagram and SEM diagram are respectively a control diagram, a schematic diagram after paper cutting treatment, a schematic diagram of treatment in parallel to the stretching direction, and a schematic diagram of treatment in perpendicular to the stretching direction; Fig. 9 1 is a schematic diagram of the effect of laser parameters and groove spacing on tensile properties, and 2 is a schematic diagram of the effect of different laser powers, processing speeds and groove spacing on tensile properties; Fig.10 Schematic diagram of the influence of different parameters (laser power, gully distance, laser frequency, processing speed) on the gully geometric parameters. Schematic diagram of the influence of different laser power, gully distance, laser frequency and processing speed on the gully geometric parameters.

[0072] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a flexible and stretchable electronic device based on laser surface treatment, characterized in that: The method comprises the following steps: Step 1, setting the arrangement pattern of micro-grooves according to the performance requirements of the flexible and stretchable electronic device to be prepared; Step 2, using picosecond ultraviolet laser to ablate the substrate surface to form the micro-grooves, wherein the geometric features of the micro-grooves are adjusted by adjusting the picosecond ultraviolet laser parameters; Step 3, sputtering a functional layer on the surface of the micro-grooves; Step 4: macroscopically patterning the functional layer to obtain a flexible and stretchable electronic device.

2. The method for preparing a flexible and stretchable electronic device based on laser surface treatment according to claim 1, characterized in that: The arrangement patterns include paper-cut, snake, rectangle, fractal, dot matrix, island-bridge and Ferris wheel.

3. The method for preparing a flexible and stretchable electronic device based on laser surface treatment according to claim 1, characterized in that: By adjusting the laser processing parameters and scanning different processing parameters at different points and different areas of the substrate, the programmable stretching performance can be achieved.

4. The method for preparing a flexible and stretchable electronic device based on laser surface treatment according to claim 1, characterized in that: The material of the substrate is a superelastic material polydimethylsiloxane or polyimide.

5. The method for preparing a flexible and stretchable electronic device based on laser surface treatment according to claim 1, characterized in that: The material of the substrate is polyimide, the laser power used in picosecond ultraviolet laser ablation is 10%, the processing speed is 1000 mm / s, the repetition frequency is 200 times, and the filling interval is 10 μm.

6. The method for preparing a flexible and stretchable electronic device based on laser surface treatment according to claim 5, characterized in that: The depth of the surface micro-grooves is 1.7 μm; the functional layer is a 200-nanometer-thick Constantan alloy layer.

7. The method for preparing a flexible and stretchable electronic device based on laser surface treatment according to claim 1, characterized in that: The material of the substrate is polydimethylsiloxane; the laser power used in picosecond ultraviolet laser ablation is 50%, the processing speed is 1000 mm / s, the repetition frequency is 200 times, and the filling interval is 20 μm.

8. The method for preparing a flexible and stretchable electronic device based on laser surface treatment according to claim 7, characterized in that: The functional layer is a 100-nanometer-thick Au / Cr alloy layer; the depth of the surface micro-grooves is 4.3 μm.

9. A flexible and stretchable electronic device, characterized in that: The flexible and stretchable electronic device is prepared by the preparation method of the flexible and stretchable electronic device based on laser surface treatment according to any one of claims 1 to 8.

10. Application of the flexible stretchable electronic device according to claim 9 in health monitoring, rehabilitation medicine, smart industry and aerospace.

Images