CN111432618A - Preparation method and product of absorption type flexible transparent electromagnetic shielding film - Google Patents
Preparation method and product of absorption type flexible transparent electromagnetic shielding film Download PDFInfo
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Abstract
The invention relates to a preparation method and a product of an absorption type flexible transparent electromagnetic shielding film, belonging to the technical field of electromagnetic shielding. The preparation method comprises the following steps: the method comprises the following steps of sequentially coating and preparing a flexible transparent polymer film layer I, a ferromagnetic nanowire network structure layer and a flexible transparent polymer film layer II on a cleaned substrate, and applying a magnetic field to enable ferromagnetic nanowires to be distributed to form an ordered network structure when the ferromagnetic nanowire network structure layer is coated and prepared. The shielding film prepared by the method has high shielding effectiveness, high light transmittance, good flexibility and excellent electromagnetic wave absorbing capacity, can effectively avoid secondary electromagnetic radiation pollution caused by shielding mainly based on a reflection mechanism, has good engineering application potential, and is simple and easy to operate, low in raw material cost and easy to industrialize.
Description
Technical Field
The invention belongs to the technical field of electromagnetic shielding, and particularly relates to a preparation method and a product of an absorption type flexible transparent electromagnetic shielding film.
Background
Electromagnetic radiation pollution has become one of the most prominent physical pollutions of the ecological environment in the 21 st century. The serious electromagnetic radiation interference not only affects normal wireless communication and endangers the safe and stable operation of instruments and equipment, but also directly or indirectly causes serious economic loss and casualties, and long-term strong electromagnetic radiation can cause certain tissue pathological changes, thereby seriously threatening the health of human bodies. Therefore, researchers at home and abroad are constantly dedicated to developing effective electromagnetic shielding materials so as to reduce or even eliminate adverse effects caused by electromagnetic radiation and obtain good effects. However, with the rise of flexible electronics, particularly wearable devices and flexible optoelectronic devices typified by portable and foldable displays, the rapid development of conventional electromagnetic shielding materials has brought about great challenges. Because, the shielding material suitable for the flexible photoelectric device must have high shielding effectiveness, high visible light transmittance, high flexibility, ultra-thinness, light weight, and excellent durability.
At present, flexible transparent electromagnetic shielding is mainly achieved by forming a micro-scale metal mesh using periodic regular patterns designed and processed (using photolithography, crack templates or inkjet printing) using metal wires. For example, chinese patent CN201310122824.1 discloses that a transparent aperiodic metal mesh structure is fabricated by using an aperiodic crack pattern formed by cracking a titanium dioxide solution as a template; chinese patent CN201410052260.3 is to coat photoresist on a metal-plated film and mask the photoresist for photoetching, then to carry out dry etching or wet etching, and finally to remove the photoresist to obtain a grid pattern; chinese patent CN201610412201.1 is to form an electromagnetic shielding film by coating a photoresist on a conductive substrate and performing photolithography to form a pattern structure, then selectively electrodepositing a metal pattern structure, and finally embedding the metal pattern structure into a flexible base material by imprinting. Although micro-scale metal meshes can achieve good shielding effectiveness and light transmittance, their preparation often requires complex processes and expensive equipment, resulting in high costs. Meanwhile, the diameter of the metal wire is difficult to be lower than 30 micrometers, electromagnetic shielding with high visible light transmittance is difficult to realize, and the repeated fatigue bending property is poor.
In recent years, researches show that metal nanowires (mainly silver nanowires and copper nanowires) are dispersed in a solvent and coated on a flexible substrate to form a continuous conductive network structure, so that good light transmittance and good shielding efficiency can be obtained, and the continuous conductive network structure has the advantages of simplicity and convenience in operation, good quality, high strength and low cost, so that the continuous conductive network structure becomes an ideal scheme for developing a flexible transparent electromagnetic shielding film, for example, a Polyethersulfone (PES)/silver nanowires/polyethylene terephthalate (PET) interlayer film is prepared in a manner of combining Meyer rod rolling and drawing rod coating by Lei Yao teaching team of hong Kong City university (M.J.Hu et al., L angmuir,2012,28(18): 7101): 7106), the electromagnetic shielding film has the advantages of high shielding efficiency and high shielding efficiency, and is 23dB (8-12 GHz) and 81%. Sichuan compact Li Zheng teaching team of Japan (L. C.Jia. Jia et al., applied materials and intercalar nanowires & 10): 2018. the electromagnetic shielding efficiency is increased by a reflective nano wire coating film, so that the electromagnetic shielding efficiency is easily reduced by a pair of electromagnetic shielding nanowires and the electromagnetic shielding film is easily reduced by the incident radiation of electromagnetic shielding nanowires and the electromagnetic shielding nanowire, the electromagnetic shielding film is easily reduced by the electromagnetic radiation caused by the electromagnetic radiation of a reflective coating mechanism of a reflective nano wire coating film, such as a conductive film, the electromagnetic shielding film is hardly reduced by the electromagnetic shielding efficiency of a conductive film, the electromagnetic shielding film is increased by the electromagnetic shielding efficiency of a reflective silver nanowire reflection type electromagnetic shielding film, the electromagnetic shielding film is increased by the electromagnetic shielding film, the electromagnetic shielding efficiency of a conductive film, the electromagnetic shielding film, the electromagnetic radiation of a reflective silver nanowire is increased by the electromagnetic.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a method for preparing an absorption type flexible transparent electromagnetic shielding film; the second purpose is to provide an absorption type flexible transparent electromagnetic shielding film.
In order to achieve the purpose, the invention provides the following technical scheme:
1. a preparation method of an absorption type flexible transparent electromagnetic shielding film comprises the following steps: the method comprises the following steps of sequentially coating and preparing a flexible transparent polymer film layer I, a ferromagnetic nanowire network structure layer and a flexible transparent polymer film layer II on a cleaned substrate, and applying a magnetic field to enable ferromagnetic nanowires to be distributed to form an ordered network structure when the ferromagnetic nanowire network structure layer is coated and prepared.
Preferably, the areal density of the ferromagnetic nanowires in the ferromagnetic nanowire network structure layer is 50-180mg/m2。
Preferably, the direction of the magnetic field is parallel to the surface of the polymer film layer I, and the magnetic field application angle is rotated within the surface of the polymer film layer I when the magnetic field is applied.
Preferably, the angle is 0-360 °.
Preferably, the magnetic field strength is 0.5-0.8T.
Preferably, the magnetic field is generated by any one of a permanent magnet, an electromagnet, or a halbach pole array.
Preferably, the flexible transparent polymer film layer I or the flexible transparent polymer film layer II is prepared by one of knife coating, micro gravure printing, roll coating and spin coating; the coating mode when the ferromagnetic nanowire network structure layer is prepared is one of roll coating, ink jet printing, spin coating, spray coating, blade coating or micro-gravure printing.
Preferably, the substrate is made of one of glass, ceramic, plastic, rubber or metal.
Preferably, the substrate is cleaned in the following manner: and ultrasonically cleaning the substrate by using a cleaning agent, alternately washing the substrate for 3-5 times by using deionized water and absolute ethyl alcohol, and blow-drying the substrate by using high-purity nitrogen or argon or naturally airing the substrate.
Preferably, the method for preparing the flexible transparent polymer film layer I by coating comprises the following steps: coating the high-molecular prepolymer I on a substrate and then curing to obtain the high-molecular prepolymer I; the method for preparing the flexible transparent polymer film layer II by coating comprises the following steps: and (3) coating the high-molecular prepolymer II on the ferromagnetic nanowire network structure layer and then curing.
Preferably, the viscosity of the high molecular prepolymer I or the high molecular prepolymer II is 10-1000 mPa.s; the high molecular prepolymer I or the high molecular prepolymer II is one of polyurethane, polydimethylsiloxane or Ecoflex.
Preferably, the thickness of the flexible transparent polymer film layer I or the flexible transparent polymer film layer II is 80-300 μm.
Preferably, when the flexible transparent polymer film layer I or the flexible transparent polymer film layer II is prepared, the curing temperature is 30-80 ℃, and the curing time is 0.5-2 h.
Preferably, the method for preparing the ferromagnetic nanowire network structure layer by coating comprises the following steps of mixing a viscosity regulator and water according to a mass ratio of 1.5-5:1 to form a solution A, mixing a dispersing agent and water according to a mass ratio of 1:6-15 to form a solution B, soaking the ferromagnetic nanowires in an acid solution with the concentration of 0.01-0.15 mol/L for 2-5min, collecting, cleaning to be neutral, dispersing in the solution A, uniformly mixing, adding the solution B, uniformly mixing to obtain a ferromagnetic nanowire coating liquid, coating the ferromagnetic nanowires on the flexible transparent polymer film layer I, continuously applying a magnetic field in a drying process to enable the ferromagnetic nanowires to be distributed to form an ordered network structure, repeating the coating-drying and applying the magnetic field until the ferromagnetic nanowire surface density meeting the requirement is obtained, wherein the mass ratio of the solution A, the cleaned ferromagnetic nanowires in the ferromagnetic nanowire coating liquid to the solution B is 200-.
Preferably, the viscosity modifier is one of hydroxypropyl methyl cellulose, hydroxyethyl cellulose, poloxamer or cyclohexanol; the dispersing agent is one of Sago-dispersant 9760, polyethylene glycol, sodium sulfamate or polyvinyl alcohol; the average wire diameter range of the ferromagnetic nanowire is 40-160nm, the average wire length range is 18-35 mu m, and the length-diameter ratio range is 115-625.
Preferably, the material of the ferromagnetic nanowire is at least one of iron, cobalt or nickel, or an alloy of at least two of iron, cobalt or nickel.
Preferably, the acidic solution is one of glacial acetic acid, dilute hydrochloric acid, dilute nitric acid, sulfuric acid, or dilute chromic acid.
Preferably, the collection mode is permanent magnet adsorption, negative pressure suction filtration or positive pressure suction filtration.
Preferably, the cleaning mode is that water and absolute ethyl alcohol are alternately cleaned.
2. The absorption type flexible transparent electromagnetic shielding film prepared by the method.
The invention has the beneficial effects that: the invention provides a preparation method and a product of an absorption type flexible transparent electromagnetic shielding film. The sandwich structure is adopted, and the upper layer and the lower layer are flexible transparent polymer film layers, so that the film is endowed with excellent flexibility. The ferromagnetic nanowire network structure layer is arranged in the middle, so that the possibility of pollution, scraping or abrasion can be well avoided. And the ferromagnetic nanowire with high length-diameter ratio has good toughness, can bear repeated bending without displacement and breakage in the structure, can overcome the defect of poor bending fatigue property of the micro-scale metal mesh, and can realize that the performance does not change obviously after being bent for thousands of times under a small curvature radius. The shielding film has the advantages of high shielding efficiency, high light transmittance, good flexibility, excellent electromagnetic wave absorbing capacity, capability of effectively avoiding secondary electromagnetic radiation pollution caused by shielding mainly based on a reflection mechanism, good engineering application potential, simple and easy preparation method, low raw material cost and easy industrialization.
When the ferromagnetic nanowires are used for preparing the ferromagnetic nanowire network structure layer in the electromagnetic shielding film, the ferromagnetic nanowires are used as raw materials, and a magnetic field is applied to construct an ordered network structure, so that the percolation threshold is reduced, the finally prepared electromagnetic shielding film can be ensured to have higher shielding efficiency and high light transmittance under the condition of filling less ferromagnetic nanowires, the contradiction between the filling amount of conductive particles and the light transmittance commonly existing in the conventional transparent electromagnetic shielding material is overcome, and the high shielding efficiency and the light transmittance are considered under the condition of low filling amount. Furthermore, by optimizing the surface density of the ferromagnetic nanowires in the ferromagnetic nanowire network structure layer and the angle of the applied rotating magnetic field, a double-layer or multilayer ordered iron nanowire grid is formed, and by utilizing the characteristic that the grid period of the ferromagnetic nanowire network is far smaller than the wavelength of microwave and far larger than the wavelengths of visible light and infrared light, the electromagnetic shielding of a microwave band is enhanced, and meanwhile, the high light transmittance of a wide frequency band is ensured, so that the shielding efficiency and the light transmittance of the finally prepared electromagnetic shielding film can be further improved. In addition, the ferromagnetic metal nanowires are used as magnetic metals, have high magnetic conductivity, can dissipate the energy of electromagnetic waves through various attenuation mechanisms, and have excellent electromagnetic wave absorption capacity, so that electromagnetic shielding can be realized by attenuating and absorbing the electromagnetic waves instead of reflecting the electromagnetic waves, and the defect of secondary electromagnetic radiation pollution caused by shielding mainly based on a reflection mechanism is effectively avoided.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.
Drawings
For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic view showing a process for preparing an absorptive flexible transparent electromagnetic shielding film according to example 1;
fig. 2 is an SEM image of iron nanowires collected in example 1 (fig. 2 (a) is an SEM image at 1000 times, and fig. 2 (b) is an SEM image at 30000 times);
FIG. 3 is a graph showing the results of the microwave absorption characteristic test of the iron nanowires collected in example 1;
FIG. 4 is a partially enlarged schematic view of the ordered network structure of ferromagnetic nanowires in examples 2 and 5;
FIG. 5 is a schematic diagram showing a partial enlargement of the ordered network structure of ferromagnetic nanowires in example 3;
FIG. 6 is a partially enlarged schematic view of the ordered network structure of ferromagnetic nanowires in example 4.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
Example 1
An absorption type flexible transparent electromagnetic shielding film is prepared, and a schematic preparation process is shown in fig. 1:
(1) ultrasonically cleaning a glass substrate by using a cleaning agent, alternately flushing the glass substrate for 3 times by using deionized water and absolute ethyl alcohol, and drying the glass substrate by using high-purity nitrogen for later use;
(2) coating polyurethane with the viscosity of 1000mPa.s on the glass substrate treated in the step (1) by a scraper, and curing at 80 ℃ for 0.5h to obtain a flexible transparent polymer film layer I with the thickness of 150 mu m;
(3) mixing hydroxypropyl methylcellulose and deionized water according to a mass ratio of 3.5:1, mixing for 1h at a speed of 120r/min by using a shaking table to form a solution A, mixing Sago-dispersant 9760 and the deionized water according to a mass ratio of 1:9, mixing for 1h at a speed of 100r/min by using a shaking table to form a solution B, soaking iron nanowires with an average wire diameter of 80nm, an average wire length of 28 micrometers and a length-diameter ratio of 350 in dilute hydrochloric acid with a concentration of 0.05 mol/L for 3min, adsorbing and collecting with a permanent magnet, alternately cleaning with deionized water and absolute ethyl alcohol to be neutral, dispersing in the solution A, mixing for 0.5h at a speed of 110r/min by using a shaking table, adding the solution B, mixing for 1h at a speed of 110r/min by using a shaking table to obtain an iron nanowire coating solution, coating the iron nanowires on a flexible transparent polymer film layer I obtained in the step (2), continuously generating a magnetic field with a strength of 0.6T in the natural drying process of coating, coating the iron nanowires on a flexible polymer film layer I, and coating the flexible polymer film layer I, wherein the flexible polymer layer I is coated in an angle of a flexible transparent polymer network structure, and the flexible polymer film I is repeatedly applied to form a flexible magnetic field I, and the flexible polymer film I, and the flexibleThe surface density of the order iron nano wire is 90mg/m2Preparing a ferromagnetic nanowire network structure layer, wherein the mass ratio of the solution A in the iron nanowire coating liquid to the cleaned iron nanowire to the solution B is 150:200: 0.8;
(4) and (3) spin-coating polyurethane with the viscosity of 300mPa.s on the ferromagnetic nanowire network structure layer obtained in the step (2), curing at 80 ℃ for 1h to obtain a flexible transparent polymer film layer II with the thickness of 100 micrometers, and stripping the absorption type flexible transparent electromagnetic shielding film with the sandwich structure consisting of the flexible transparent polymer film layer I, the ferromagnetic nanowire network structure layer and the transparent polymer film layer II from the substrate. The shielding effectiveness of the absorption type flexible transparent electromagnetic shielding film is about 22.5dB, and the light transmittance is about 88%.
Example 2
Preparing an absorption-type flexible transparent electromagnetic shielding film
(1) Ultrasonically cleaning a polyethylene glycol terephthalate plastic substrate by using a cleaning agent, alternately washing the substrate for 5 times by using deionized water and absolute ethyl alcohol, and drying the substrate by using high-purity argon for later use;
(2) coating polydimethylsiloxane with the viscosity of 200mPa.s on the plastic substrate treated in the step (1) by a roller through a Meyer rod, and curing for 45min at 40 ℃ to obtain a flexible transparent polymer film layer I with the thickness of 150 mu m;
(3) mixing cyclohexanol and deionized water in a mass ratio of 5:1, mixing with a shaking table at a speed of 200r/min for 0.5h to form a solution A, mixing polyethylene glycol and deionized water in a mass ratio of 1:6, mixing with a shaking table at a speed of 180r/min for 45min to form a solution B, soaking nickel nanowires with an average wire diameter of 100nm, an average wire length of 25 microns and a length-diameter ratio of 250 in sulfuric acid with a concentration of 0.02 mol/L for 4min, performing suction filtration at positive pressure, collecting, alternately cleaning with deionized water and absolute ethyl alcohol to neutrality, dispersing in the solution A, mixing with a shaking table at a speed of 90r/min for 45min, adding the solution B, mixing with a shaking table at a speed of 100r/min for 45min to obtain a nickel nanowire coating liquid, spin-coating the nickel nanowire coating liquid on the flexible transparent polymer film layer I obtained in the step (2), and naturally drying the nickel nanowire coating liquid on the magnetic pole array with HalbachContinuously generating a magnetic field with the strength of 0.5T in a column to enable the nickel nanowires to be distributed to form an ordered network structure, wherein the direction of the magnetic field is parallel to the surface of the flexible transparent polymer film layer I, rotating a magnetic field application angle in the surface of the flexible transparent polymer film layer I when the magnetic field is applied, the angle is 0 degree, and repeating the coating-drying and magnetic field application procedures until the surface density of the nickel nanowires is 60mg/m2Then the magnetic field application angle is adjusted to be 90 degrees, and then the coating-drying and magnetic field application procedures are repeated until the total surface density of the nickel nano wires is 120mg/m2Preparing a ferromagnetic nanowire network structure layer, wherein the mass ratio of the solution A in the nickel nanowire coating liquid to the cleaned nickel nanowire to the solution B is 180:360: 1;
(4) and (3) rolling polydimethylsiloxane with the viscosity of 200mPa.s onto the ferromagnetic nanowire network structure layer obtained in the step (2) by using a Meyer rod, curing for 45min at 40 ℃ to obtain a flexible transparent polymer film layer II with the thickness of 100 mu m, and stripping the sandwich structure absorption type flexible transparent electromagnetic shielding film composed of the flexible transparent polymer film layer I, the ferromagnetic nanowire network structure layer and the transparent polymer film layer II from the substrate. The shielding effectiveness of the absorption-type flexible transparent electromagnetic shielding film is about 24dB, and the light transmittance is about 85%.
Example 3
Preparing an absorption-type flexible transparent electromagnetic shielding film
(1) Ultrasonically cleaning a ceramic substrate by using a cleaning agent, alternately flushing the ceramic substrate for 4 times by using deionized water and absolute ethyl alcohol, and drying the ceramic substrate by using high-purity nitrogen for later use;
(2) printing Ecoflex micro-gravure with the viscosity of 50mPa.s on the ceramic substrate treated in the step (1), and curing at 60 ℃ for 30min to obtain a flexible transparent polymer film layer I with the thickness of 80 mu m;
(3) mixing hydroxyethyl cellulose and deionized water according to the mass ratio of 1.5:1, and mixing for 45min at the speed of 150r/min by using a shaking table to form a solution A; mixing sodium sulfamate and deionized water according to a mass ratio of 1:8, and mixing for 30min at a speed of 100r/min by using a shaking table to form a solution B; the cobalt nano-wire with the average wire diameter of 160nm, the average wire length of 32 mu m and the length-diameter ratio of 200 is used for concentration of 0.0Soaking 1 mol/L diluted nitric acid for 4min, collecting with permanent magnet, soaking with deionized water and anhydrous ethanol for 5min, collecting with iron nanowire with average wire diameter of 60nm, average wire length of 27 μm and length-diameter ratio of 450 with glacial acetic acid with concentration of 0.05 mol/L, soaking with permanent magnet, washing with deionized water and anhydrous ethanol to neutral, dispersing the collected cobalt nanowire and iron nanowire in solution A, mixing at 120r/min for 30min with a shaker, adding solution B, mixing at 90r/min for 50min with a shaker to obtain cobalt/iron nanowire mixed coating solution, spraying the cobalt/iron nanowire mixed coating solution on the flexible transparent polymer film layer I obtained in step (2), naturally drying with the permanent magnet continuously generating magnetic field with strength of 0.6T to form ordered network structure by the cobalt nanowire and iron nanowire distribution, wherein the direction of the magnetic field is parallel to the surface of the flexible transparent polymer film layer I, applying the magnetic field on the flexible transparent polymer film layer I, coating the cobalt nanowire with magnetic field density of 0 mg-75 mg, and drying with angle of 0 mg-3575 mg of iron nanowire surface2After the magnetic field application angle is adjusted to 60 degrees, the coating-drying and magnetic field application procedures are repeated again until the total surface density of the cobalt nanowires and the iron nanowires is 150mg/m2Preparing a ferromagnetic nanowire network structure layer, wherein the mass ratio of the solution A in the cobalt/iron nanowire mixed coating liquid, the cleaned cobalt nanowire, the cleaned iron nanowire and the solution B is 200:150:150: 0.6;
(4) printing Ecoflex micro-gravure with the viscosity of 50mPa.s on the ferromagnetic nanowire network structure layer obtained in the step (2), curing at 60 ℃ for 30min to obtain a flexible transparent polymer film layer II with the thickness of 80 mu m, and peeling off the absorption type flexible transparent electromagnetic shielding film with the sandwich structure consisting of the flexible transparent polymer film layer I, the ferromagnetic nanowire network structure layer and the transparent polymer film layer II from the substrate. The shielding effectiveness of the absorption type flexible transparent electromagnetic shielding film is about 27dB, and the light transmittance is about 80.5%.
Example 4
Preparing an absorption-type flexible transparent electromagnetic shielding film
(1) Ultrasonically cleaning an ethylene propylene diene monomer substrate by using a cleaning agent, alternately washing the substrate for 5 times by using deionized water and absolute ethyl alcohol, and naturally drying the substrate for later use;
(2) coating polyurethane with the viscosity of 800mPa.s on the rubber substrate treated in the step (1) by a Meyer rod in a roller way, and curing at 50 ℃ for 1.2h to obtain a flexible transparent polymer film layer I with the thickness of 200 mu m;
(3) mixing poloxamer and deionized water according to a mass ratio of 3:1, and mixing for 15min at a speed of 230r/min by using a shaking table to form a solution A; mixing polyvinyl alcohol and deionized water according to a mass ratio of 1:10, and mixing for 20min at a speed of 180r/min by using a shaking table to form a solution B;
soaking iron nanowires with the average wire diameter of 72nm, the average wire length of 27.4 microns and the length-diameter ratio of 380 in dilute chromic acid with the concentration of 0.03 mol/L for 3.5min, adsorbing and collecting the iron nanowires by using a permanent magnet, alternately cleaning the iron nanowires to be neutral by using deionized water and absolute ethyl alcohol, dispersing the iron nanowires in the solution A, mixing the iron nanowires for 25min at the speed of 150r/min by using a shaking table, adding the solution B, mixing the iron nanowires for 40min at the speed of 120r/min by using the shaking table again to obtain an iron nanowire coating liquid, wherein the mass ratio of the solution A, the cleaned iron nanowires and the solution B in the iron nanowire coating liquid is 180:230: 0.7;
soaking the nickel nanowire with the average wire diameter of 90nm, the average wire length of 28.8 mu m and the length-diameter ratio of 320 in dilute hydrochloric acid with the concentration of 0.01 mol/L for 5min, adsorbing and collecting the nickel nanowire by using a permanent magnet, alternately cleaning the nickel nanowire to be neutral by using deionized water and absolute ethyl alcohol, dispersing the nickel nanowire in the solution A, mixing the nickel nanowire in the solution A at the speed of 150r/min for 30min by using a shaking table, adding the solution B, mixing the nickel nanowire in the solution B for 50min at the speed of 120r/min by using the shaking table to obtain a nickel nanowire coating solution, wherein the mass ratio of the solution A, the cleaned nickel nanowire to the solution B in the nickel nanowire coating solution is 160:210: 0.;
spin-coating iron nanowire coating liquid on the flexible transparent polymer film layer I obtained in the step (2), and enabling the iron nanowires to be distributed to form an ordered network structure by continuously generating a magnetic field with the strength of 0.6T by using a Halbach magnetic pole array in the natural airing process, wherein the direction of the magnetic field is parallel to the surface of the flexible transparent polymer film layer I, and the flexible transparent polymer film layer I is subjected to magnetic field applicationRotating the magnetic field applying angle in the surface of the polymer film layer I, wherein the angle is 0 degree, repeating the coating-drying and magnetic field applying procedures until the surface density of the iron nanowire is 25mg/m2Forming an iron nanowire ordered network structure film layer, spin-coating a nickel nanowire coating liquid on the iron nanowire ordered network structure film layer, continuously generating a magnetic field with the strength of 0.6T by using a Halbach magnetic pole array in the natural airing process to enable the nickel nanowires to be distributed to form an ordered network structure, wherein the direction of the magnetic field is parallel to the surface of the iron nanowire ordered network structure film layer, rotating a magnetic field application angle in the surface of the iron nanowire ordered network structure film layer when the magnetic field is applied, the angle is 30 degrees, repeating the coating-drying process and the magnetic field application process until the surface density of the nickel nanowires is 25mg/m2I.e. the areal density of the total ferromagnetic nanowires is 50mg/m2Obtaining a ferromagnetic nanowire network structure layer;
(4) and (3) coating polyurethane with the viscosity of 800mPa.s on the ferromagnetic nanowire network structure layer obtained in the step (2) by using a Meyer rod in a roller manner, curing for 1.2h at 50 ℃ to obtain a flexible transparent polymer film layer II with the thickness of 200 mu m, and stripping the absorption type flexible transparent electromagnetic shielding film with the sandwich structure consisting of the flexible transparent polymer film layer I, the ferromagnetic nanowire network structure layer and the transparent polymer film layer II from the substrate. The shielding effectiveness of the absorption type flexible transparent electromagnetic shielding film is about 16dB, and the light transmittance is about 91%.
Example 5
Preparing an absorption-type flexible transparent electromagnetic shielding film
(1) Ultrasonically cleaning a stainless steel metal substrate by using a cleaning agent, alternately washing the stainless steel metal substrate for 4 times by using deionized water and absolute ethyl alcohol, and drying the stainless steel metal substrate by using high-purity argon for later use;
(2) rolling polydimethylsiloxane with the viscosity of 300mPa.s onto the metal plastic substrate treated in the step (1) by using a Meyer rod, and curing at 50 ℃ for 40min to obtain a flexible transparent polymer film layer I with the thickness of 120 mu m;
(3) mixing poloxamer and deionized water according to a mass ratio of 4.5:1, and mixing for 35min at a speed of 120r/min by using a shaking table to form a solution A; mixing polyvinyl alcohol and deionized waterMixing according to a mass ratio of 1:15, mixing for 40min at a speed of 160r/min by using a shaking table to form a solution B, soaking the iron-nickel alloy nanowires with an average wire diameter of 125nm, an average wire length of 32 mu m and a length-diameter ratio of 256 in dilute nitric acid with a concentration of 0.04 mol/L for 4min, collecting with a permanent magnet, alternately cleaning with deionized water and absolute ethyl alcohol to be neutral, dispersing in the solution A, mixing for 40min at a speed of 120r/min by using the shaking table, adding the solution B, mixing for 30min at a speed of 90r/min by using the shaking table to obtain an iron-nickel alloy nanowire coating solution, spin-coating the iron-nickel alloy nanowire coating solution on the flexible transparent polymer film layer I obtained in the step (2), and continuously generating a magnetic field with a strength of 0.5T by using the permanent magnet in a natural airing process to enable the distribution of the iron-nickel alloy nanowires to form an ordered network structure, wherein the direction of the magnetic field is parallel to the surface of the flexible transparent polymer film layer I, and the magnetic field is applied at an angle of 0 DEG, and the magnetic field drying process is repeated until the surface of the magnetic field density of the2Then the magnetic field application angle is adjusted to be 90 degrees, and then the coating-drying procedure is repeated again until the total surface density of the iron-nickel alloy nano wire is 150mg/m2Preparing a ferromagnetic nanowire network structure layer, wherein the mass ratio of the solution A in the iron-nickel alloy nanowire coating liquid to the cleaned iron-nickel alloy nanowire to the solution B is 160:380: 0.8;
(4) and (3) coating polyurethane with the viscosity of 300mPa.s onto the ferromagnetic nanowire network structure layer obtained in the step (2) by using a Meyer rod in a roller manner, curing for 40min at 60 ℃ to obtain a flexible transparent polymer film layer II with the thickness of 120 mu m, and stripping the absorption type flexible transparent electromagnetic shielding film with the sandwich structure, which is formed by the flexible transparent polymer film layer I, the ferromagnetic nanowire network structure layer and the transparent polymer film layer II, from the substrate. The shielding effectiveness of the absorption-type flexible transparent electromagnetic shielding film is about 30.5dB, and the light transmittance is about 83 percent.
Fig. 2 is an SEM image of the iron nanowires collected in example 1, wherein (a) in fig. 2 is an SEM image at 1000 times, which shows that the synthesized iron nanowires do not have an agglomeration phenomenon and exhibit a good monodispersity; in fig. 2, (b) is an SEM image at 30000 times, and it is known that the diameter of the iron nanowire is 100nm or less and is relatively uniform. The good monodispersity and uniformity of the iron nanowire network are beneficial to constructing the ordered distribution iron nanowire network under a magnetic field
Fig. 3 is a graph of the test result of the microwave absorption characteristics of the iron nanowires collected in example 1, and it can be seen from fig. 3 that the iron nanowires with low content exhibit excellent electromagnetic wave absorption performance, the minimum reflection loss can reach-25.94 dB (at 5.84 GHz), and the effective absorption bandwidth less than-10 dB (corresponding to 90% of electromagnetic wave energy absorption) can reach 3.52GHz (4.72-8.24GHz), so that the flexible transparent electromagnetic shielding thin film of the iron nanowires can realize shielding mainly based on an absorption mechanism.
Fig. 4 is a partially enlarged schematic view of the ordered network structure of ferromagnetic nanowires in example 2 and example 5.
Fig. 5 is a partially enlarged schematic view of the ordered network structure of ferromagnetic nanowires in example 3.
FIG. 6 is a partially enlarged schematic view of the ordered network structure of ferromagnetic nanowires in example 4.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
Claims (10)
1. A preparation method of an absorption type flexible transparent electromagnetic shielding film is characterized by comprising the following steps: the method comprises the following steps of sequentially coating and preparing a flexible transparent polymer film layer I, a ferromagnetic nanowire network structure layer and a flexible transparent polymer film layer II on a cleaned substrate, and applying a magnetic field to enable ferromagnetic nanowires to be distributed to form an ordered network structure when the ferromagnetic nanowire network structure layer is coated and prepared.
2. The method of claim 1, wherein the areal density of ferromagnetic nanowires in the ferromagnetic nanowire network structure layer is from 50 to 180mg/m2。
3. The method of claim 1, wherein the magnetic field is oriented parallel to the polymer film I surface and the magnetic field is applied by rotating the magnetic field application angle within the polymer film I surface.
4. The method of claim 2, wherein the magnetic field strength is 0.5-0.8T.
5. The method of any one of claims 1-4, wherein the coating produces the flexible transparent polymeric film layer I by the following method: coating the high-molecular prepolymer I on a substrate and then curing to obtain the high-molecular prepolymer I; the method for preparing the flexible transparent polymer film layer II by coating comprises the following steps: and (3) coating the high-molecular prepolymer II on the ferromagnetic nanowire network structure layer and then curing.
6. The method of claim 5, wherein the high molecular prepolymer I or high molecular prepolymer II each has a viscosity of 10 to 1000 mpa.s; the high molecular prepolymer I or the high molecular prepolymer II is one of polyurethane, polydimethylsiloxane or Ecoflex.
7. The method of claim 5, wherein the thickness of the flexible transparent polymer film layer I or the flexible transparent polymer film layer II is 80-300 μm.
8. The method as claimed in any one of claims 1 to 4, wherein the method for preparing the ferromagnetic nanowire network structure layer by coating comprises the steps of mixing a viscosity regulator and water according to a mass ratio of 1.5-5:1 to form a solution A, mixing a dispersing agent and water according to a mass ratio of 1:6-15 to form a solution B, soaking the ferromagnetic nanowires in an acid solution with a concentration of 0.01-0.15 mol/L for 2-5min, collecting and cleaning the ferromagnetic nanowires to be neutral, dispersing the ferromagnetic nanowires in the solution A, uniformly mixing the solution A and the solution B, adding the solution B, uniformly mixing the solution B again to obtain the ferromagnetic nanowires, coating the ferromagnetic nanowire coating liquid on the flexible transparent polymer film layer I, continuously applying a magnetic field in the drying process to enable the ferromagnetic nanowires to be distributed to form an ordered network structure, and repeating the coating-drying process and the magnetic field applying process until the ferromagnetic nanowire surface density meets the requirement, wherein the mass ratio of the solution A, the ferromagnetic nanowires after cleaning and the solution B in the nanowire coating liquid is 150-.
9. The method of claim 8, wherein the viscosity modifier is one of hydroxypropyl methylcellulose, hydroxyethyl cellulose, poloxamer or cyclohexanol; the dispersing agent is one of Sago-dispersant 9760, polyethylene glycol, sodium sulfamate or polyvinyl alcohol; the average wire diameter range of the ferromagnetic nanowire is 40-160nm, the average wire length range is 18-35 mu m, and the length-diameter ratio range is 115-625.
10. An absorptive, flexible, transparent electromagnetic shielding film made by the method of any one of claims 1-9.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112672626A (en) * | 2020-12-18 | 2021-04-16 | 成都佳驰电子科技有限公司 | Multi-band magnetic wave-absorbing film and preparation method thereof |
| CN112930100A (en) * | 2021-01-20 | 2021-06-08 | 中国电子科技集团公司第三十三研究所 | Metal transparentized electromagnetic shielding material and preparation method thereof |
| CN113795133A (en) * | 2021-09-13 | 2021-12-14 | 合肥工业大学 | Preparation method of layered magnetic orientation photosensitive resin-based electromagnetic wave absorber |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1457630A (en) * | 2001-03-02 | 2003-11-19 | 日立化成工业株式会社 | Electromagnetic shield film, electromagnetic shield unit and display |
| CN1555072A (en) * | 2003-12-21 | 2004-12-15 | 浙江大学 | Method for producing nano magnetic network structure film |
| CN101045858A (en) * | 2006-03-30 | 2007-10-03 | 丰田合成株式会社 | Insulator with high thermal conductivity and method for producing the same |
| CN102105820A (en) * | 2008-06-05 | 2011-06-22 | 3M创新有限公司 | Ultrathin transparent EMI shielding filter |
| CN103753881A (en) * | 2014-01-16 | 2014-04-30 | 北京科技大学 | Method for preparing wave absorbing material from magnetic fluid |
| CN105034243A (en) * | 2015-07-10 | 2015-11-11 | 彭晓领 | Injection molding preparation method for magnetic composite material in magnetostatic field |
| CN106498712A (en) * | 2016-12-05 | 2017-03-15 | 中国建筑材料科学研究总院 | Electro-magnetic wave absorption grid material and preparation method thereof |
| CN109996432A (en) * | 2019-05-07 | 2019-07-09 | 苏州麦田光电技术有限公司 | A kind of full-embedded type metallic mesh electromagnetic wave shield film and production method |
-
2020
- 2020-03-06 CN CN202010152889.0A patent/CN111432618A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1457630A (en) * | 2001-03-02 | 2003-11-19 | 日立化成工业株式会社 | Electromagnetic shield film, electromagnetic shield unit and display |
| CN1555072A (en) * | 2003-12-21 | 2004-12-15 | 浙江大学 | Method for producing nano magnetic network structure film |
| CN101045858A (en) * | 2006-03-30 | 2007-10-03 | 丰田合成株式会社 | Insulator with high thermal conductivity and method for producing the same |
| CN102105820A (en) * | 2008-06-05 | 2011-06-22 | 3M创新有限公司 | Ultrathin transparent EMI shielding filter |
| CN103753881A (en) * | 2014-01-16 | 2014-04-30 | 北京科技大学 | Method for preparing wave absorbing material from magnetic fluid |
| CN105034243A (en) * | 2015-07-10 | 2015-11-11 | 彭晓领 | Injection molding preparation method for magnetic composite material in magnetostatic field |
| CN106498712A (en) * | 2016-12-05 | 2017-03-15 | 中国建筑材料科学研究总院 | Electro-magnetic wave absorption grid material and preparation method thereof |
| CN109996432A (en) * | 2019-05-07 | 2019-07-09 | 苏州麦田光电技术有限公司 | A kind of full-embedded type metallic mesh electromagnetic wave shield film and production method |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112672626A (en) * | 2020-12-18 | 2021-04-16 | 成都佳驰电子科技有限公司 | Multi-band magnetic wave-absorbing film and preparation method thereof |
| CN112930100A (en) * | 2021-01-20 | 2021-06-08 | 中国电子科技集团公司第三十三研究所 | Metal transparentized electromagnetic shielding material and preparation method thereof |
| CN112930100B (en) * | 2021-01-20 | 2022-05-17 | 中国电子科技集团公司第三十三研究所 | Preparation method of metal transparentized electromagnetic shielding material |
| CN113795133A (en) * | 2021-09-13 | 2021-12-14 | 合肥工业大学 | Preparation method of layered magnetic orientation photosensitive resin-based electromagnetic wave absorber |
| CN113795133B (en) * | 2021-09-13 | 2024-01-26 | 合肥工业大学 | Preparation method of layered magnetically oriented photosensitive resin-based electromagnetic wave absorber |
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