CN114369360B - High-stability three-dimensional braided state flexible electromagnetic shielding film and preparation method thereof - Google Patents
High-stability three-dimensional braided state flexible electromagnetic shielding film and preparation method thereof Download PDFInfo
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Abstract
A flexible electromagnetic shielding film with high stability and three-dimensional knitting grid is a film with a 3D structure of an inverted rectangular pyramid array formed by taking PI (polyimide) as a matrix, embedding a knitting silver nanowire grid structure which is distributed in three dimensions into the PI matrix and forming an inverted rectangular pyramid array together with the matrix. The three-dimensional braided silver nanowire mesh electromagnetic shielding film prepared by the method has excellent mechanical stability, the bending radius is 1.8mm, the bending times are more than 1300 times, the resistance of the film is not changed remarkably, and the resistance change is less than 1%; the transparency is excellent, and the light transmittance reaches more than 92%; in addition, the electromagnetic shielding performance is excellent, the electromagnetic shielding performance reaches 30-45dB, and after 1300 cycles, the electromagnetic shielding performance is basically unchanged, and the stability is excellent.
Description
Technical Field
The invention relates to the technical field of electromagnetic shielding materials, in particular to a high-stability three-dimensional braided silver nanowire flexible electromagnetic shielding film and a preparation method thereof.
Background
With the development of social electronics and informatization, the electromagnetic spectrum is increasingly dense, the electromagnetic power density in unit volume is rapidly increased, and the electromagnetic environment is increasingly deteriorated due to the fact that high-level devices or equipment are used in a large amount in a mixing mode. Electromagnetic shielding is a metallic shield made of an electrically or magnetically conductive material that limits electromagnetic interference to a range that allows interference sources to be suppressed or attenuated when coupled or radiated from one side of the shield to the other.
In recent years, there have been many studies on development of flexible transparent electromagnetic shielding films, among which silver is favored by researchers because of its excellent conductivity. At present, a silver nanowire electromagnetic shielding film forms a conductive network through random sedimentation and lap joint of silver nanowires on a substrate, the random network lap joint points are fewer and easy to fall off, the mechanical property is poor, the resistance of an electrode is greatly changed in the mechanical deformation process, the resistance cannot be recovered after denaturation, the stability is extremely poor, the film is invalid, the electromagnetic shielding performance of the film is poor, if the electromagnetic shielding performance of the film is required to be improved, the thickness of the film is required to be increased, the lap joint rate between silver nanowires is increased, the millimeter level is reached, the size is thicker, the transparency is poor, the application is limited, and the problem of poor mechanical stability cannot be solved by the method.
Therefore, it is an object of the art to prepare a flexible electromagnetic shielding film of silver nanowires having high light transmittance, excellent electromagnetic shielding performance, excellent mechanical stability, and extremely small thickness dimension.
Disclosure of Invention
Based on the technical problems, the invention aims to provide a preparation method of a high-stability silver nanowire electromagnetic shielding grid film, wherein silver nanowires in the prepared film are in a three-dimensional (3D) distributed and woven grid structure, and the high-stability silver nanowire electromagnetic shielding grid film has excellent mechanical stability and electromagnetic shielding performance.
The invention aims at realizing the following technical scheme:
a high-stability three-dimensional braided state grid flexible electromagnetic shielding film is characterized in that: the grid film takes PI (polyimide) as a matrix, is of a three-dimensional distributed woven silver nanowire grid structure, is embedded into the matrix, and forms a three-dimensional structure of an inverted rectangular pyramid array together with the matrix.
The matrix material can also be selected from PDMS (polydimethylsiloxane) or PET (polyethylene terephthalate).
A preparation method of a high-stability three-dimensional braided flexible electromagnetic shielding film is characterized by comprising the following steps: coating silver nanowire ink on a silicon template with an inverted quadrangular pyramid microcavity array and coated with metallic molybdenum on the surface, spin-coating PI matrix stock solution containing a diluent after solvent in the ink is evaporated, placing the silicon template into ammonia water solution after solidification, removing the PI film from the silicon template, drying to obtain a transparent electromagnetic shielding film with three-dimensional braided silver nanowire, spin-coating photoresist positive photoresist on a double-sided oxidized (100) silicon wafer, baking and solidifying, exposing by using a mask with a square array structure, developing, after hard baking, placing the silicon plate into BOE solution, standing for 7-10 min after etching, washing, drying, removing the photoresist mask, etching in 40-90 ℃ potassium hydroxide solution, adding ultrasonic treatment after 30min of etching start, and accelerating etching of the silicon template to obtain the silicon template with the inverted quadrangular pyramid microcavity array.
The BOE solution is 49% HF aqueous solution and 40% NH 4 The volume ratio of the aqueous solution of F is 1:6.
The side wall edges of the cavity of the inverted rectangular pyramid microcavity array form orthogonal grid lines. According to the invention, a layer of liquid film is formed on a silicon template with a specific surface microstructure through silver nanowire ink, and two different micro-flow behaviors, namely surface flow of the surface of the micro-cavity and rotary secondary flow in the cavity, are formed on the surface of the silicon wafer in the process of solvent evaporation due to the special inverted quadrangular micro-cavity structure of the surface of the silicon wafer. Due to pinning effects of the surface layer flow and the side wall of the inverted rectangular pyramid, long silver nanowires are pinned by grid lines, and along with gradual weakening of the surface layer flow, rotary secondary flow is induced to be converted into thermal capillary flow, so that the silver nanowires in the microcavity are brought to the upper edges of the orthogonal grid lines, and finally silver nanowire distribution of a woven orthogonal grid structure is formed.
Further, the square array in the photoresist mask is an array consisting of 30×30 to 300×300 μm squares.
Further, the mass fraction of the potassium hydroxide is 15-40%, the etching temperature is 40-90 ℃, and the etching time is 40-200 min.
Further, the power of the ultrasonic treatment is 100W, and the power density is 0.5-0.8W/m 2 。
In the research process, the microcavity structure such as the longitudinal depth of the cavity, the inclination degree of the side wall of the cavity and the like are found to have obvious influence on the performance of the finally formed silver nanowire three-dimensional grid, and the flowing change and the distribution state of the silver nanowire solution in the microcavity can be influenced. The inverted quadrangular microcavity array provided by the invention realizes controllable adjustment of silver nanowire ink microfluid, realizes uniform orthogonal distribution of silver nanowires along grid lines, further generates certain influence on the distribution of the silver nanowires through viscosity and fluidity of liquid PI stock solution in a curing process, and coats the edges of the silver nanowires in an orthogonal braiding state three-dimensional structure, so that the silver nanowires are embedded into a PI film, the phase relation among the silver nanowires is fixed, stable ohmic contact is formed, the lap joint rate among the silver nanowires is increased, and meanwhile, the PI coating further protects the silver nanowires from being damaged by oxidization and the like, and the high conductivity of the silver nanowires is maintained.
In the process of etching the inverted rectangular pyramid microcavity on the silicon template by adopting potassium hydroxide, the concentration of potassium hydroxide changes along with the extension of etching time, so that the etching speed changes, and as the etching depth increases, the edge of the side wall of the cavity can collapse, so that the grid structure of the edge of the cavity is damaged, and the silver nanowire cannot form a vertically woven structure along the edge of the cavity in the later stage. Therefore, in the potassium hydroxide etching process, the proper etchable rate is determined by adjusting the original concentration of potassium hydroxide and the etching temperature, ultrasonic treatment is added in the middle of etching to accelerate the etching rate, and meanwhile, stress accumulation in the side wall of the grid structure is counteracted, so that the stability and the non-collapse of the structure are ensured.
Further, the length of silver nanowires of the silver nanowire solution is 30-200 mu m, the diameter is 20-150 nm, and the concentration of the solution is 1.2-5 mg/mL.
Different matrix materials have different fluidity and viscosity, and if the selected materials and the curing process are controlled improperly, the stock solution can infiltrate from the gaps of the adjacent silver nanowires, so that the lap joint of the silver nanowires is blocked, the lap joint between the silver nanowires is reduced, the film resistance is increased, and the electromagnetic shielding performance is reduced.
Further, the volume ratio of PI to the diluent in the PI stock solution is 10:0.5-2, the curing temperature is 80-225 ℃, and the curing time is 10-180 min.
The preparation method of the high-stability three-dimensional braided flexible electromagnetic shielding film is characterized by comprising the following steps of:
s01 preparation of silicon template
Spin-coating photoresist positive photoresist on a double-sided oxidized (100) silicon wafer, baking at 80-100 ℃ for curing, exposing by using a mask with a square array of 30 multiplied by 30-300 multiplied by 300 mu m, developing, hard baking, placing a silicon plate in a BOE solution, standing for 7-10 min, removing the photoresist mask by using photoresist stripping solution, etching for 40-200 min in a potassium hydroxide solution with the mass concentration of 15-40% at 40-90 ℃, adding ultrasonic treatment after the etching is started for 30min, wherein the ultrasonic power is 100W and the power density is 0.5-0.8W/m 2 Obtaining a silicon template with an inverted rectangular pyramid microcavity array;
s02 preparation of silver nanowire layer
Depositing a metal molybdenum layer on the surface of a silicon template with an inverted rectangular pyramid microcavity array, uniformly coating silver nanowire ink with the concentration of 1.2-5 mg/mL on the surface of the silicon template to form a layer of silver nanowire ink liquid film, and repeatedly coating silver nanowires and drying after the silver nanowire ink solvent evaporates, wherein the repetition times are 2-35, and in the silver nanowire ink, the length of the silver nanowires is 30-200 mu m, and the diameter is 20-150 nm;
s03 covering PI matrix
Spin-coating PI stock solution consisting of a diluent and PI with the volume ratio of 0.5-2:10 on the surface of a silicon template, curing for 10-200 min at 80-225 ℃ to form a PI film, placing the silicon template in an ammonia water solution with the mass fraction of 0.5%, removing the PI film from the silicon template, and drying at 30-90 ℃ to obtain the three-dimensional braided silver nanowire transparent electromagnetic shielding film.
In the preparation method, the substrate material can also be PDMS.
The invention has the following technical effects:
the three-dimensional braided silver nanowire mesh electromagnetic shielding film prepared by the invention
(1) The mechanical stability is excellent, the bending radius is 1.8mm, the bending times are more than 1300 times, the resistance of the film does not change obviously, the resistance change is less than 1%, and the film is not easy to fall off in the use process;
(2) The film has excellent transparency, and the light transmittance reaches more than 92%;
(3) The electromagnetic shielding effectiveness of the film reaches 30-45dB, and after 1300 cycles, the electromagnetic shielding effectiveness is basically not reduced, and the film has excellent stability.
Drawings
Fig. 1: the invention provides a process for preparing a silver nanowire electromagnetic shielding grid film.
Fig. 2: the invention prepares the silicon template inverted rectangular pyramid cavity structure and the grid distribution structure of the silver nanowires.
Fig. 3: the silver nanowire electromagnetic shielding grid film prepared by the method has the structure.
Fig. 4: the resistance change rate curve graph of the silver nanowire electromagnetic shielding grid film prepared by the invention after repeated bending.
Fig. 5: the electromagnetic shielding effectiveness curve graph of the silver nanowire electromagnetic shielding grid film prepared by the invention.
Detailed Description
The present invention is described in detail below by way of examples, which are necessary to be pointed out herein for further illustration of the invention and are not to be construed as limiting the scope of the invention, since numerous insubstantial modifications and adaptations of the invention will be to those skilled in the art in light of the foregoing disclosure.
Example 1
The preparation method of the high-stability three-dimensional braided flexible electromagnetic shielding film comprises the following steps:
s01 preparation of silicon template
Spin-coating photoresist positive resist on a double-sided oxidized (100) silicon wafer, baking at 80deg.C for curing, exposing with a square array mask with the size of 30×30 μm, developing, hard baking, standing the silicon plate in BOE solution for 7min, washing with deionized water after etching, drying, removing photoresist mask with photoresist solution, etching in potassium hydroxide solution with the mass concentration of 15% at 40deg.C for 40min, and adding ultrasonic treatment with the ultrasonic power of 100W and the power density of 0.5W/m after the etching is started for 30min 2 Obtaining a silicon template with an inverted rectangular pyramid microcavity array;
s02 preparation of silver nanowire layer
A layer of metal molybdenum layer is deposited on the surface of a silicon template with an inverted rectangular pyramid microcavity array by magnetron sputtering, silver nanowire ink with the concentration of 5mg/mL is uniformly coated on the surface of the silicon template to form a layer of silver nanowire ink liquid film, after a silver nanowire ink solvent is evaporated, silver nanowires are repeatedly coated and dried, the repetition number is 2, and in the silver nanowire ink, the length of the silver nanowire is 30 mu m, and the diameter is 20nm;
s03 covering PI matrix
Spin-coating PI stock solution consisting of a diluent and PI with the volume ratio of 0.5:10 on the surface of a silicon template, curing for 200min at 80 ℃ to form a PI film, placing the silicon template in an ammonia water solution with the mass fraction of 0.5%, removing the PI film from the silicon template, and drying at 30 ℃ to obtain the three-dimensional braided silver nanowire transparent electromagnetic shielding film.
As shown in fig. 2 (a), the silicon template prepared in step S01 of the present invention has an inverted quadrangular pyramid-shaped microcavity structure, and after the silver nanowire ink is coated, the distribution of the silver nanowires in the microcavity is shown in fig. 2 (b). After the silicon template is removed, the obtained silver nanowire 3D grid structure electromagnetic shielding film is mainly distributed in a grid structure formed by the edges of the rectangular pyramid as shown in fig. 3, and a small amount of electromagnetic shielding film is uniformly distributed on the side walls of the rectangular pyramid, so that a uniform 3D grid structure is formed. The transmittance of the three-dimensional braided silver nanowire flexible electromagnetic shielding film prepared by the embodiment reaches 93.7%, after the bending times exceed 1300 times, the change of the film resistance is less than 1%, and the electromagnetic shielding effectiveness is still kept at about 30 dB.
In the preparation process, if ultrasonic assistance is not added in the potassium hydroxide etching process, as the depth increases, the etching speed is not controlled due to the gradual increase of the potassium hydroxide concentration, stress accumulation is formed in the side wall of the cavity, a complete rectangular pyramid shape is not formed yet, and the formed orthogonal grid edges are broken. After the etching is performed to a certain extent, ultrasonic assistance is added, so that the etching is accelerated, meanwhile, the accumulation of stress is eliminated, the integral formation of the inverted rectangular pyramid microcavity structure is ensured, the structure is stable, and the orthogonal grid is not broken.
Example 2
The preparation method of the high-stability three-dimensional braided flexible electromagnetic shielding film comprises the following steps:
s01 preparation of silicon template
Spin-coating photoresist positive resist on a double-sided oxidized (100) silicon wafer, baking at 100deg.C for curing, exposing with a mask having a square array of 300×300 μm, developing, hard baking, standing the silicon plate in BOE solution for 7-10 min, cleaning with deionized water after etching, drying, removing photoresist mask with photoresist solution, etching in 40% potassium hydroxide solution at 90deg.C for 200min, starting for 30min, adding ultrasonic treatment with ultrasonic power of 100W and power density of 0.8W/m 2 Obtaining a silicon template with an inverted rectangular pyramid microcavity array;
s02 preparation of silver nanowire layer
A layer of metal molybdenum layer is deposited on the surface of a silicon template with an inverted rectangular pyramid through magnetron sputtering, silver nanowire ink with the concentration of 1.2mg/mL is uniformly coated on the surface of the silicon template to form a layer of silver nanowire ink liquid film, after a silver nanowire ink solvent is evaporated, silver nanowires are repeatedly coated and dried, the repetition number is 35, and in the silver nanowire ink, the length of the silver nanowire is 200 mu m, and the diameter is 150nm;
s03 covering PI matrix
Spin-coating PI stock solution consisting of a diluent and PI with a volume ratio of 2:10 on the surface of a silicon template, curing for 10min at 225 ℃ to form a PI film, placing the silicon template in an ammonia water solution with a mass fraction of 0.5%, removing the PI film from the silicon template, and drying at 90 ℃ to obtain the three-dimensional braided silver nanowire transparent electromagnetic shielding film.
The transmittance of the prepared three-dimensional braided silver nanowire flexible electromagnetic shielding film reaches 92.6%, the resistance change of the film is less than 1% after the bending times are over 1300 times, and the electromagnetic shielding efficiency is still kept at about 45 dB.
Example 3
The preparation method of the high-stability three-dimensional braided flexible electromagnetic shielding film comprises the following steps:
s01 preparation of silicon template
Spin-coating photoresist positive resist on a double-sided oxidized (100) silicon wafer, baking at 90 ℃ for curing, exposing by using a mask with a square array of 50 multiplied by 50 mu m, developing, hard baking, placing a silicon plate in a BOE solution, standing for 7-10 min, after etching, washing with deionized water, drying, removing the photoresist mask by using photoresist removing solution, etching in a potassium hydroxide solution with the mass concentration of 30% at 60 ℃ for 100min, starting etching for 30min, adding ultrasonic treatment with the ultrasonic power of 100W and the power density of 0.6W/m 2 Obtaining a silicon template with an inverted rectangular pyramid microcavity array;
s02 preparation of silver nanowire layer
A layer of metal molybdenum layer is deposited on the surface of a silicon template with an inverted rectangular pyramid microcavity array by magnetron sputtering, silver nanowire ink with the concentration of 3mg/mL is uniformly coated on the surface of the silicon template to form a layer of silver nanowire ink liquid film, after a silver nanowire ink solvent is evaporated, silver nanowires are repeatedly coated and dried for 20 times, wherein in the silver nanowire ink, the length of the silver nanowire is 100 mu m, and the diameter of the silver nanowire is 80nm;
s03 covering PI matrix
Spin-coating PI stock solution consisting of a diluent and PI with the volume ratio of 1:10 on the surface of a silicon template, curing for 110min at 140 ℃ to form a PI film, placing the silicon template in an ammonia water solution with the mass fraction of 0.5%, removing the PI film from the silicon template, and drying at 50 ℃ to obtain the three-dimensional braided silver nanowire transparent electromagnetic shielding film.
The diluent (curing agent) is a matched component when the base stock solution is purchased.
The transmittance of the prepared three-dimensional braided silver nanowire flexible electromagnetic shielding film reaches 93.4%, the bending radius is 1.8mm, the resistance change of the film is less than 1% after the bending times are over 1300 times, the electromagnetic shielding effectiveness is still stable, and no decline occurs.
Comparative example 1
The preparation method of the silver nanowire electromagnetic shielding grid film comprises the following specific steps:
s01 preparation of silicon template
Spin-coating photoresist positive photoresist on a double-sided oxidized (100) silicon wafer, baking and curing at 90 ℃, exposing by using a mask with a square array of 50 multiplied by 50 mu m, developing, hard baking, placing a silicon plate in a BOE solution, standing for 7-10 min, removing the photoresist mask by using photoresist stripping solution, and then placing in a potassium hydroxide solution with the mass concentration of 30% at 60 ℃ for etching for 100min to form a silicon mold with an inverted pyramid frustum cavity array (the etching depth is shallow, the bottom is not completely etched, and a platform structure is left);
the remaining steps remain the same as in example 3.
The silver nanowire mesh film prepared in comparative example 1 has a regular structure. Through electromagnetic shielding effectiveness detection, under the same detection condition, the electromagnetic shielding effectiveness of the silver nanowire mesh film prepared in comparative example 1 is about 25dB, while the electromagnetic shielding effectiveness of the three-dimensional braided silver nanowire flexible electromagnetic shielding film prepared in embodiment 3 of the invention is about 40dB, as shown in fig. 5.
Example 4
The preparation method of the high-stability three-dimensional braided flexible electromagnetic shielding film comprises the following steps:
s01 preparation of silicon template
Spin-coating photoresist positive resist on a double-sided oxidized (100) silicon wafer, baking at 90 ℃ for curing, exposing by using a mask with a square array of 50 multiplied by 50 mu m, developing, hard baking, placing a silicon plate in a BOE solution, standing for 7-10 min, after etching, washing with deionized water, drying, removing the photoresist mask by using photoresist removing solution, etching in a potassium hydroxide solution with the mass concentration of 30% at 60 ℃ for 100min, starting etching for 30min, adding ultrasonic treatment with the ultrasonic power of 100W and the power density of 0.6W/m 2 Obtaining a silicon template with an inverted rectangular pyramid microcavity array;
s02 preparation of silver nanowire layer
A layer of metal molybdenum layer is deposited on the surface of a silicon template with an inverted rectangular pyramid microcavity array by magnetron sputtering, silver nanowire ink with the concentration of 3mg/mL is uniformly coated on the surface of the silicon template to form a layer of silver nanowire ink liquid film, after a silver nanowire ink solvent is evaporated, silver nanowires are repeatedly coated and dried for 20 times, wherein in the silver nanowire ink, the length of the silver nanowire is 100 mu m, and the diameter of the silver nanowire is 80nm;
s03 coating PDMS matrix
Spin-coating PDMS stock solution consisting of a diluent and PDMS in a volume ratio of 1:10 on the surface of a silicon template, curing for 110min at 140 ℃ to form a PDMS film, placing the silicon template in an ammonia water solution with a mass fraction of 0.5%, removing the PDMS film from the silicon template, and drying at 50 ℃ to obtain the transparent electromagnetic shielding film with the three-dimensional braided silver nanowire.
The transmittance of the prepared three-dimensional braided silver nanowire flexible electromagnetic shielding film reaches 92.6%, the bending radius is 1.8mm, the change of the resistance value of the film is less than 1% after the bending times are over 1300 times, the electromagnetic shielding effectiveness is still kept stable at about 37dB, and no reduction occurs.
Claims (7)
1. A high-stability three-dimensional braided state grid flexible electromagnetic shielding film is characterized in that: the film takes PI (polyimide) as a matrix, a woven silver nanowire mesh structure which is distributed in three dimensions is embedded into the matrix, and the three-dimensional silver nanowire mesh structure and the matrix form a 3D (three-dimensional) film of an inverted rectangular pyramid array; the film is prepared by the following steps: coating silver nanowire ink on a silicon template with an inverted quadrangular pyramid microcavity array and coated with metallic molybdenum on the surface, spin-coating PI stock solution containing a diluent after a solvent in the ink is evaporated, putting the silicon template into an ammonia water solution after solidification, removing the PI film from the silicon template, and carrying out ultrasonic treatment after 30min of etching start to obtain the silicon template with the inverted quadrangular pyramid.
2. A method for preparing the high-stability three-dimensional woven mesh flexible electromagnetic shielding film according to claim 1, which is characterized in that: coating silver nanowire ink on a silicon template with an inverted quadrangular pyramid microcavity array and coated with metallic molybdenum on the surface, spin-coating PI stock solution containing a diluent after a solvent in the ink is evaporated, putting the silicon template into an ammonia water solution after solidification, removing the PI film from the silicon template, and carrying out baking on the silicon template, wherein the silicon template is obtained by spin-coating photoresist positive photoresist on a double-sided silicon oxide wafer, baking and solidifying, exposing by adopting a mask with a square array structure, developing, hard baking, putting a silicon plate into a BOE solution, standing for 7-10 min, then removing the photoresist mask, etching in a potassium hydroxide solution at 40-90 ℃, and adding ultrasonic treatment after the etching is started for 30 min.
3. The method for preparing the high-stability three-dimensional woven mesh flexible electromagnetic shielding film according to claim 2, which is characterized in that: the mass fraction of the potassium hydroxide is 15-40%, the etching temperature is 40-90 ℃, and the etching time is 40-200 min.
4. A method for preparing a high-stability three-dimensional woven mesh flexible electromagnetic shielding film according to claim 2 or 3, which is characterized in that: the length of the silver nanowire in the silver nanowire ink is 30-200 mu m, the diameter is 20-150 nm, and the ink concentration is 1.2-5 mg/mL.
5. A method for preparing a high-stability three-dimensional woven mesh flexible electromagnetic shielding film according to claim 2 or 3, which is characterized in that: the volume ratio of the matrix material to the diluent in the PI stock solution is 10:0.5-2, the curing temperature is 80-225 ℃, and the curing time is 10-180 min.
6. The method for preparing the high-stability three-dimensional woven mesh flexible electromagnetic shielding film according to claim 4, which is characterized in that: the volume ratio of PI to the diluent in the PI stock solution is 10:0.5-2, the curing temperature is 80-225 ℃, and the curing time is 10-180 min.
7. The preparation method of the high-stability three-dimensional woven grid flexible electromagnetic shielding film is characterized by comprising the following steps of:
s01 preparation of silicon template
Spin-coating photoresist positive photoresist on a double-sided silicon oxide wafer, baking and curing at 80-100 ℃, exposing by using a mask with a square array, developing, hard baking, placing a silicon plate in a BOE solution, standing for 7-10 min, removing the photoresist mask, etching in a potassium hydroxide solution with the mass concentration of 15-40% at 40-90 ℃ for 40-200 min, and adding ultrasonic treatment after the etching is started for 30min to obtain the silicon template with the inverted quadrangular pyramid microcavity array;
s02 preparation of silver nanowire layer
Depositing a metal molybdenum layer on the surface of a silicon template with an inverted rectangular pyramid microcavity array, uniformly coating silver nanowire ink with the concentration of 1.2-5 mg/mL on the surface of the silicon template to form a layer of silver nanowire ink liquid film, and repeatedly coating silver nanowires and drying after the silver nanowire ink solvent evaporates, wherein the repetition times are 2-35, and in the silver nanowire ink, the length of the silver nanowires is 30-200 mu m, and the diameter is 20-150 nm;
s03 covering PI matrix
Spin-coating PI stock solution consisting of a diluent and PI with the volume ratio of 0.5-2:10 on the surface of a silicon template, curing for 10-200 min at 80-225 ℃ to form a PI film, placing the silicon template in an ammonia water solution with the mass fraction of 0.5%, stripping the PI film from the silicon template, and drying at 30-90 ℃ to obtain the three-dimensional braided silver nanowire transparent electromagnetic shielding film.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110648801A (en) * | 2018-06-27 | 2020-01-03 | 宁波山功新材料科技有限公司 | Silver nanowire electromagnetic shielding film and preparation method thereof |
| EP3689978A1 (en) * | 2019-01-31 | 2020-08-05 | Korea Electronics Technology Institute | Composite conductive substrate and manufacturing method thereof |
| CN112885928A (en) * | 2021-03-30 | 2021-06-01 | 东南大学 | Method for quickly forming octagonal pyramid structure on silicon wafer |
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| TWI625226B (en) * | 2016-04-01 | 2018-06-01 | 律勝科技股份有限公司 | Flexible and transparent polyimide laminate and manufacturing method thereof |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| EP3689978A1 (en) * | 2019-01-31 | 2020-08-05 | Korea Electronics Technology Institute | Composite conductive substrate and manufacturing method thereof |
| CN112885928A (en) * | 2021-03-30 | 2021-06-01 | 东南大学 | Method for quickly forming octagonal pyramid structure on silicon wafer |
Non-Patent Citations (3)
| Title |
|---|
| A high sensitive flexible pressure sensor designed by silver nanowires embedded in polyimide (AgNW-PI);Hongfang Li,et al.;《Micromachines》;第10卷(第3期);第206页 * |
| Highly flexible and transparent film heaters based on polyimide films embedded with silver nanowires;Qijin Huang,et al.;《Rsc Advances》;第5卷(第57期);第45836-45842页 * |
| Jingjing Ma, et al..Ultralightweight silver nanowires hybrid polyimide composite foams for high-performance electromagnetic interference shielding.《ACS applied materials & interfaces》.2014,第7卷(第1期),第563-576页. * |
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