Electromagnetic shielding-thermal insulation polymer flexible film and preparation method and application thereof

Abstract

The application discloses an electromagnetic shielding-heat insulation polymer flexible film and a preparation method and application thereof, and belongs to the technical field of electromagnetic shielding-heat insulation. The preparation method uses poly 3,4-ethylenedioxythiophene (PEDOT) nanofibers prepared by a solvothermal method as an electromagnetic shielding-heat insulation base material, and then a simple dopant is doped, and then an ultrasonic dispersion-vacuum filtration-freeze drying process is used to directly obtain a PEDOT nanofiber film with a compact structure. Not only is the preparation process simple and controllable, but also the dopant can be added and blended to form hydrogen bonds for crosslinking in the ultrasonic dispersion process. The electromagnetic shielding and heat insulation performance can be regulated by changing the type and mass fraction of the dopant in the preparation process. The flexible film prepared by the application has excellent electromagnetic shielding performance, good heat insulation performance and an extremely thin thickness, and overcomes the problems of a large thickness, high cost, poor performance and a complex process of a traditional separated electromagnetic protective cover and heat insulation sheet, and has good industrial application potential.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic shielding and heat insulation technology, and relates to an electromagnetic shielding and heat insulation polymer flexible film and its preparation method. Specifically, it relates to a single-doped poly(3,4-ethylenedioxythiophene) (PEDOT) polymer and its preparation method and application of an electromagnetic shielding and heat insulation polymer flexible film. Background Technology

[0002] As electronic components continue to evolve towards miniaturization, integration, and high power density, electromagnetic interference (EMI) and heat accumulation problems are becoming increasingly prominent. These two issues are mutually coupled and mutually restrictive, becoming a key bottleneck limiting the performance improvement and long-term stable operation of electronic devices. Dual-functional electromagnetic shielding and thermal insulation materials can effectively block harmful electromagnetic radiation generated by electronic devices while also achieving efficient control of heat transfer, preventing thermosensitive components from failing due to overheating or environmental temperature fluctuations. This is a crucial technical solution for addressing EMI and heat accumulation problems in electronic devices and ensuring their reliable operation. PEDOT and its derivative PEDOT:PSS, as the most industrially mature conductive polymer, possess significant advantages in the field of integrated electromagnetic shielding and thermal insulation. However, intrinsic PEDOT suffers from poor solubility in most solvents, difficult processing, low intrinsic conductivity, and easy oxidation in air, severely limiting its practical applications. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) composites are typically prepared using polystyrene sulfonate (PSS) as the doping anion. However, the insulating PSS component significantly hinders the transport of free carriers on the PEDOT main chain, resulting in low system conductivity (10). -5(~10 S / cm); Meanwhile, PSS is highly hygroscopic and easily swells in humid or physiological environments, leading to a significant decrease in the service stability of PEDOT:PSS. To address this, secondary dopants are introduced to plasticize and modify the insulating PSS. By controlling the type and concentration of dopants and promoting the crystallization and ordered arrangement of PEDOT segments, the conductivity of PEDOT:PSS can continuously transition from an insulator to a metallic state. This wide-range tunable conductivity provides important support for its application in electromagnetic shielding and related optoelectronic fields. However, this process is complex. Furthermore, existing related patent research still has significant limitations. CN115094621B uses PEDOT:PSS to coat MXene fiber aerogel, which utilizes high conductivity to improve shielding effect and porous structure to achieve thermal insulation, but only leverages the conductivity of PEDOT, neglecting the interfacial bonding issue, and the aerogel is thick and prone to collapse. The InZnSey@C / PEDOT:PSS composite film prepared by CN121427259A is only a physical blend, lacking chemical bonding, resulting in high interfacial charge transfer resistance and difficulty in constructing a continuous three-dimensional conductive network. CN119711178A prepared PEDOT conductive cotton through in-situ polymerization, which, while possessing both flexibility and conductivity, lacks effective bonding between components, and its performance stability under extreme environments is unknown. CN107146842A obtained a flexible self-supporting membrane by ultrasonically dispersing and vacuum filtering PEDOT nanofibers and SWCNTs, and improved conductivity and thermal conductivity by incorporating carbon nanotubes. However, the interaction between SWCNTs and PEDOT is not apparent, the drying method is not mentioned, and SWCNTs are relatively expensive, leading to high application costs. Overall, while existing PEDOT or PEDOT:PSS-based coatings and composite films are easy to prepare, they generally suffer from poor interfacial compatibility, insufficient structural control, poor stability, and complex processes, making it difficult to meet high-end requirements for electromagnetic shielding and thermal insulation performance.

[0003] As electronic devices continue to evolve towards miniaturization, integration, and high power, electromagnetic interference and heat accumulation problems are becoming increasingly serious, placing higher demands on the comprehensive performance, flexibility, and service stability of materials. Intrinsic PEDOT exhibits low electrical and thermal conductivity and weak intermolecular forces, making it difficult to form a regular and efficient conductive network. How to construct anisotropic conductive networks at the microscale through simple single-stage doping, utilizing chemical bonding and intermolecular interactions, and transforming interface modulation mechanisms into macroscopic performance improvements, while simultaneously simplifying the process for industrial-scale fabrication, has become a key technical challenge urgently needing to be solved in this field. Summary of the Invention

[0004] In view of this, the purpose of this invention is to address the problems existing in the prior art by providing an electromagnetic shielding-heat insulation polymer flexible film and its preparation method. This process is simple to operate, has adjustable performance, and has market promotion and application value.

[0005] To achieve the above objectives, the present invention first provides an electromagnetic shielding-heat insulation polymer flexible film. The electromagnetic shielding-heat insulation polymer flexible film is prepared by adding an electromagnetic shielding-heat insulation substrate and a dopant to a solvent, ultrasonically dispersing them to obtain a uniform dispersion, vacuum filtering the dispersion to obtain a solid, and then freeze-drying the solid. The electromagnetic shielding-heat insulation substrate is PEDOT nanofibers; the dopant is one of ethanol, ethylene glycol, propylene glycol, glycerol, methanethiol, 1,2-ethylenedithiol, acetic acid, and oxalic acid; the thickness of the electromagnetic shielding-heat insulation polymer flexible film is 30~110 μm.

[0006] Preferably, the solvent is methanol; the concentration of PEDOT nanofibers in the dispersion is 1-5 wt%, and the concentration of dopant is 1-10 wt%.

[0007] It is worth noting that the electromagnetic shielding-heat insulation polymer flexible film disclosed in this invention has excellent electromagnetic shielding and heat insulation performance. The flexible film with a thickness of 50 μm has an average shielding effectiveness of 38.62~64.70 dB in the K and R frequency bands (18~40 GHz), an average in-plane thermal conductivity of 0.228~2.878 W / (m·K), an average inter-plane thermal conductivity of 0.0583~0.0163 W / (m·K), and an electrical conductivity of 127.8~266.9 S / cm.

[0008] The PEDOT nanofibers were prepared by a solvothermal method, specifically as follows: sodium dodecyl sulfate and ferric chloride hexahydrate were added to deionized water and stirred in a water bath to form a uniform and stable micelle dispersion. Then, 3,4-ethylenedioxythiophene monomer was added dropwise to obtain a mixed solution system. The mixed solution system was reacted in a water bath. After the reaction was completed, the mixture was cooled, centrifuged, washed with deionized water and methanol, and filtered under reduced pressure to finally obtain PEDOT nanofibers.

[0009] Preferably, the molar ratio of sodium dodecyl sulfate, 3,4-ethylenedioxythiophene, and ferric chloride hexahydrate is 2.19~8.76 : 1 : 1.095~4.38; and the concentration of 3,4-ethylenedioxythiophene in the mixed solution system is 0.034~0.136 mol / L.

[0010] Preferably, the temperature of the water bath stirring is 40~60 ℃ and the time is 1~2 h; the temperature of the water bath reaction of the mixed solution system is 40~60 ℃ and the time is 4~8 h.

[0011] Secondly, the present invention also provides a method for preparing the electromagnetic shielding-heat insulation polymer flexible film as described above. The preparation method adopts an ultrasonic dispersion-vacuum filtration-freeze drying film formation process, specifically including the following steps: dispersing the electromagnetic shielding-heat insulation substrate and dopant in methanol, ultrasonically dispersing to obtain a dispersion, vacuum filtering the dispersion through a sand core funnel to the surface of a polytetrafluoroethylene filter membrane to obtain a solid precursor, clamping the solid with a glass sheet, placing it in a vacuum freeze dryer for freeze drying to form the electromagnetic shielding-heat insulation polymer flexible film.

[0012] Preferably, the ultrasonic dispersion temperature is 40 ℃ and the time is 3~6 h; the vacuum filtration pressure is -0.1MPa; and the pore size of the polytetrafluoroethylene filter membrane is 2 μm.

[0013] Preferably, the freeze-drying temperature is -80 ℃, the pressure is 100 Pa, and the time is 2~4 h.

[0014] It is worth noting that, compared with existing methods, the ultrasonic dispersion-vacuum filtration-freeze drying process of this invention produces an electromagnetic shielding-heat insulation polymer flexible membrane with a thickness as low as 50 μm, exhibiting excellent flexibility, high experimental repeatability, simple steps, and low requirements for instrument precision. The freeze-drying process improves the yield of the composite membrane, reduces the gaps between PEDOT chains to a certain extent, and improves the flexibility and toughness of the composite membrane. The material prepared by this method also has excellent electromagnetic shielding and heat insulation properties. By adding a multidentate dopant (multiple hydroxyl and thiol groups) that can form hydrogen bonds, “O---HO” and “O---HS” hydrogen bonds are formed between PEDOT chains, enhancing chain orientation, reducing the interchain spacing, and forming a more complete conductive network, thus improving conductivity and shielding effectiveness. The presence of hydrogen bonds also reduces phonon scattering between chains to a certain extent, improving thermal conductivity. Furthermore, the electromagnetic shielding and heat insulation properties can be controlled by adjusting the type and mass fraction of the dopant.

[0015] Finally, this invention also provides an application of the electromagnetic shielding-heat insulation polymer flexible film described above in electronic and electrical equipment. Because the film possesses excellent flexibility, electromagnetic shielding performance, and extremely low thermal conductivity, the electromagnetic shielding-heat insulation polymer flexible film can be specifically applied in the fields of electronics, communications, automobiles, medical devices, home appliances, aerospace, security monitoring, and navigation.

[0016] In summary, this invention provides an electromagnetic shielding-heat insulation polymer flexible film, its preparation method, and its application. Compared with the prior art, this invention has the following significant advantages:

[0017] (1) The PEDOT nanofiber electromagnetic shielding-thermal insulation substrate provided by the present invention is prepared by a mild and simple solvothermal method, which has strong process controllability, high yield and good reproducibility.

[0018] (2) The electromagnetic shielding-heat insulation polymer flexible film proposed in this invention is formed by ultrasonic dispersion-vacuum filtration-freeze drying. The process is simple, has excellent repeatability, and is easy to prepare on a large scale. The resulting film has excellent electromagnetic shielding performance, ultra-low thermal conductivity and good flexibility.

[0019] (3) This invention systematically reveals the regulation law of different types and mass fractions of dopants on the electromagnetic shielding-thermal insulation performance of polymer flexible films, and establishes a preparation route for doped PEDOT polymer electromagnetic shielding-thermal insulation polymer flexible films. This method is simple to operate, environmentally friendly, has low requirements for equipment precision, good controllability, and the obtained material has both excellent electromagnetic shielding and thermal insulation performance, and has good prospects for industrial application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a picture of the product obtained in Embodiment 1 of the present invention folded into a paper crane.

[0022] Figure 2 These are physical images of the products obtained in Examples 1 to 6 of the present invention.

[0023] Figure 3 The images shown are actual pictures of Embodiments 1 and 2 of the present invention. The left image is of Embodiment 1, and the right image is of Embodiment 2.

[0024] Figure 4 This is a phase image of the product obtained in Example 1 of the present invention under XRD.

[0025] Figure 5 This is an image showing the elemental composition of the product obtained in Example 1 of the present invention under IR.

[0026] Figure 6 The image shows the morphology of the product obtained in Example 1 of this invention under a scanning electron microscope.

[0027] Figure 7 This is an XRD image of the product obtained in Example 3 of the present invention.

[0028] Figure 8This is an image showing the elemental composition of the product obtained in Example 3 of the present invention under IR.

[0029] Figure 9 This is a scanning electron microscope image of the product obtained in Example 3 of the present invention.

[0030] Figure 10 This is an XRD image of the product obtained in Example 4 of the present invention.

[0031] Figure 11 This is an image showing the elemental composition of the product obtained in Example 4 of the present invention under IR.

[0032] Figure 12 This is a scanning electron microscope image of the product obtained in Example 4 of the present invention.

[0033] Figure 13 This is an XRD image of the product obtained in Example 5 of the present invention.

[0034] Figure 14 This is an image showing the elemental composition of the product obtained in Example 5 of the present invention under IR.

[0035] Figure 15 This is a scanning electron microscope image of the product obtained in Example 5 of the present invention.

[0036] Figure 16 This is an XRD image of the product obtained in Example 6 of the present invention.

[0037] Figure 17 This is an image showing the elemental composition of the product obtained in Example 6 of the present invention under IR.

[0038] Figure 18 This is a scanning electron microscope image of the product obtained in Example 6 of the present invention.

[0039] Figure 19 This is an XRD image of the product obtained in Example 7 of the present invention.

[0040] Figure 20 This is an image showing the elemental composition of the product obtained in Example 7 of the present invention under IR.

[0041] Figure 21 This is a scanning electron microscope image of the product obtained in Example 7 of the present invention.

[0042] Figure 22 This is a scanning electron microscope image of the product obtained in Example 8 of the present invention.

[0043] Figure 23 This is a scanning electron microscope image of the product obtained in Example 9 of the present invention.

[0044] Figure 24 This is a scanning electron microscope image of the product obtained in Example 10 of the present invention.

[0045] Figure 25 This is a scanning electron microscope image of the product obtained in Example 11 of the present invention.

[0046] Figure 26 The image shows the morphology of the product obtained in Example 12 of this invention under a scanning electron microscope.

[0047] Figure 27 This is a scanning electron microscope image of the product obtained in Example 13 of the present invention.

[0048] Figure 28 This is an image showing the thickness of the product obtained in Example 12 of the present invention, measured using vernier calipers.

[0049] Figure 29 This is an image showing the thickness of the product obtained in Example 14 of the present invention, measured using vernier calipers.

[0050] Figure 30 This is an image showing the thickness of the product obtained in Example 15 of the present invention, measured using vernier calipers.

[0051] Figure 31 This is an image showing the thickness of the product obtained in Example 16 of the present invention, measured using vernier calipers. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in the embodiments of this application, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementations and is not intended to limit the scope of this disclosure.

[0054] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; other experimental methods and technical means not specifically mentioned herein refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0055] To better illustrate the content of this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail in order to highlight the main points of this application.

[0056] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of this application.

[0057] Example 1 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film 69.2 g of sodium dodecyl sulfate (SDS) and 32.44 g of ferric chloride hexahydrate (FeCl3·6H2O) were weighed and added to 800 mL of deionized water. The mixture was stirred in a 50 °C water bath for 1 h to form a deep yellow, homogeneous, and stable micelle dispersion. 5.944 mL of 3,4-ethylenedioxythiophene (EDOT) monomer was added dropwise, and the reaction was continued in a 50 °C water bath for 6 h until the solution color completely changed from deep yellow to blue-black. The mixture was cooled, centrifuged at 8000 rpm, washed twice with deionized water, washed three times with methanol, and the product was collected by vacuum filtration to obtain the poly(3,4-ethylenedioxythiophene) nanofiber electromagnetic shielding-thermal insulation substrate.

[0058] First, the above electromagnetic shielding-heat insulation substrate was added to 200 mL of methanol at a ratio of 5 wt%, and ultrasonically dispersed at 40 ℃ for 3 h to obtain a uniform substrate-methanol dispersion. Then, the substrate-methanol dispersion was vacuum filtered through a sand core funnel at a negative pressure of -0.1 MPa on the surface of a polytetrafluoroethylene filter membrane with a pore size of 2 μm to obtain a solid precursor. The solid precursor was clamped and fixed with a glass plate and placed in a vacuum freeze dryer at a temperature of -80 ℃ and a pressure of 100 Pa to remove the residual liquid in the solid precursor, constructing uniform pores. Through a quantitative electromagnetic shielding-heat insulation substrate, a flexible electromagnetic shielding-heat insulation polymer membrane with a thickness of 50 μm was formed.

[0059] The phase composition, elemental composition, and morphology images of the obtained products obtained above, measured by XRD, IR, and scanning electron microscopy, are shown below. Figures 4-6 As shown. Figure 4 The XRD pattern shows that the product consists of orthogonal PEDOT. Figure 5 The IR spectrum shows that the major product is PEDOT. The morphology of the product observed under a scanning electron microscope is as follows. Figure 6 As shown: the product is a nanofiber network with uniform pores.

[0060] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 40.20 dB, the average in-plane thermal conductivity was 0.285 W / (m·K), the average inter-plane thermal conductivity was 0.0583 W / (m·K), and the electrical conductivity was 171.0 S / cm.

[0061] Example 2 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film The only difference compared to the preparation steps disclosed in Example 1 is that the electromagnetic shielding-heat insulation film is formed by air drying at room temperature (20 ℃ room temperature) and normal pressure. The resulting product is as follows. Figure 3 As shown on the right. Figure 3 The left image shows an electromagnetic shielding-heat insulation polymer flexible film obtained through freeze-drying. It is clearly visible that the electromagnetic shielding-heat insulation film obtained through room temperature drying is more brittle and looser. This is likely due to: firstly, the pores between PEDOT fibers are larger at room temperature and pressure; secondly, through vacuum freeze-drying, firstly, the vacuum negative compression reduces the gaps between PEDOT fibers; and secondly, the low temperature makes the PEDOT fibers finer and denser. Therefore, freeze-drying can yield an electromagnetic shielding-heat insulation polymer flexible film with better flexibility and electrical properties.

[0062] Example 3 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film The only difference compared to the preparation steps disclosed in Example 1 is that 10 wt% anhydrous ethanol was added during the ultrasonic dispersion process at 40 °C. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0063] The phase composition, elemental composition, and morphology images of the obtained products obtained above, measured by XRD, IR, and scanning electron microscopy, are shown below. Figures 7-9 As shown. Figure 7 The XRD pattern shows that the product consists of orthogonal PEDOT. Figure 8 The IR spectrum shows that the major product is PEDOT. The morphology of the product observed under a scanning electron microscope is as follows. Figure 9 As shown: the product is a nanofiber network with uniform pores.

[0064] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 42.68 dB, the average in-plane thermal conductivity was 0.240 W / (m·K), the average inter-plane thermal conductivity was 0.0468 W / (m·K), and the electrical conductivity was 132.1 S / cm. The performance was lower than that of Example 1. The reason is that the added dopant ethanol has an additional methylene group (-CH2-) compared to methanol, which may increase the spacing of the PEDOT chains, destroy the conductive path, and reduce the performance.

[0065] Example 4 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 10 wt% ethylene glycol is added during the ultrasonic dispersion process at 40 ℃. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0066] The phase composition, elemental composition, and morphology images of the obtained products obtained above, measured by XRD, IR, and scanning electron microscopy, are shown below. Figures 10-12 As shown. Figure 10 The XRD pattern shows that the product consists of orthogonal PEDOT. Figure 11 The IR spectrum shows that the major product is PEDOT. The morphology of the product observed under a scanning electron microscope is as follows. Figure 12 As shown: the product is a nanofiber network with uniform pores.

[0067] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 53.98 dB, the average in-plane thermal conductivity was 0.265 W / (m·K), the average inter-plane thermal conductivity was 0.0358 W / (m·K), and the electrical conductivity was 174.7 S / cm.

[0068] Example 5 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 10 wt% glycerol (propanetriol) is added during the ultrasonic dispersion process at 40 ℃. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0069] The phase composition, elemental composition, and morphology images of the obtained products obtained above, measured by XRD, IR, and scanning electron microscopy, are shown below. Figures 13-15 As shown. Figure 13The XRD pattern shows that the product consists of orthogonal PEDOT. Figure 14 The IR spectrum shows that the major product is PEDOT. The morphology of the product observed under a scanning electron microscope is as follows. Figure 15 As shown: the product is a nanofiber network with uniform pores.

[0070] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 38.62 dB, the average in-plane thermal conductivity was 0.257 W / (m·K), the average inter-plane thermal conductivity was 0.0188 W / (m·K), and the electrical conductivity was 127.8 S / cm. Compared with Example 1, the performance has decreased. The reason is that the added dopant glycerol formed more hydrogen bonds with the PEDOT chain, forming multiple conductive pathways, which is not conducive to the directional flow of electrons, resulting in a decrease in performance.

[0071] Example 6 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 10 wt% methanethiol is added during the ultrasonic dispersion process at 40 ℃. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0072] The phase composition, elemental composition, and morphology images of the obtained products obtained above, measured by XRD, IR, and scanning electron microscopy, are shown below. Figures 16-18 As shown. Figure 16 The XRD pattern shows that the product consists of orthogonal PEDOT. Figure 17 The IR spectrum shows that the major product is PEDOT. The morphology of the product observed under a scanning electron microscope is as follows. Figure 18 As shown: the product is a nanofiber network with uniform pores.

[0073] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 63.91 dB, the average in-plane thermal conductivity was 0.228 W / (m·K), the average inter-plane thermal conductivity was 0.0163 W / (m·K), and the electrical conductivity was 228.0 S / cm.

[0074] Example 7 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 1,2-ethylenedithiol with a mass fraction of 10 wt% is added during the ultrasonic dispersion process at 40 ℃. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0075] The phase composition, elemental composition, and morphology images of the obtained products obtained above, measured by XRD, IR, and scanning electron microscopy, are shown below. Figures 19-21 As shown. Figure 19 The XRD pattern shows that the product consists of orthogonal PEDOT. Figure 20 The IR spectrum shows that the major product is PEDOT. The morphology of the product observed under a scanning electron microscope is as follows. Figure 21 As shown: the product is a nanofiber network with uniform pores.

[0076] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 54.74 dB, the average in-plane thermal conductivity was 0.279 W / (m·K), the average inter-plane thermal conductivity was 0.0447 W / (m·K), and the electrical conductivity was 225.4 S / cm.

[0077] Example 8 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 1 wt% glycerol (glycerol) is added during the ultrasonic dispersion process at 40 °C. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0078] The morphology of the product obtained above, observed under a scanning electron microscope, is as follows: Figure 22 As shown: the product is a nanofiber network with uniform pores.

[0079] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 47.57 dB, the average in-plane thermal conductivity was 2.567 W / (m·K), the average inter-plane thermal conductivity was 0.0481 W / (m·K), and the electrical conductivity was 171.2 S / cm.

[0080] Example 9 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 2 wt% glycerol (glycerol by mass) is added during the ultrasonic dispersion process at 40 ℃. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0081] The morphology of the product obtained above, observed under a scanning electron microscope, is as follows: Figure 23 As shown: the product is a nanofiber network with uniform pores.

[0082] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 53.53 dB, the average in-plane thermal conductivity was 2.778 W / (m·K), the average inter-plane thermal conductivity was 0.0511 W / (m·K), and the electrical conductivity was 231.8 S / cm.

[0083] Example 10 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 3 wt% glycerol (propanetriol) is added during the ultrasonic dispersion process at 40 °C. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0084] The morphology of the product obtained above, observed under a scanning electron microscope, is as follows: Figure 24 As shown: the product is a nanofiber network with uniform pores.

[0085] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 60.16 dB, the average in-plane thermal conductivity was 2.814 W / (m·K), the average inter-plane thermal conductivity was 0.0522 W / (m·K), and the electrical conductivity was 252.5 S / cm.

[0086] Example 11 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 4 wt% glycerol (propanetriol) is added during the ultrasonic dispersion process at 40 ℃. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0087] The morphology of the product obtained above, observed under a scanning electron microscope, is as follows: Figure 25 As shown: the product is a nanofiber network with uniform pores.

[0088] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 62.71 dB, the average in-plane thermal conductivity was 2.855 W / (m·K), the average inter-plane thermal conductivity was 0.0555 W / (m·K), and the electrical conductivity was 259.0 S / cm.

[0089] Example 12 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 5 wt% glycerol (glycerol by mass) is added during the ultrasonic dispersion process at 40 ℃. The remaining preparation steps and process parameters are the same, resulting in an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm. Figure 28 As shown.

[0090] The morphology of the product obtained above, observed under a scanning electron microscope, is as follows: Figure 26 As shown: the product is a nanofiber network with uniform pores.

[0091] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 64.70 dB, the average in-plane thermal conductivity was 2.877 W / (m·K), the average inter-plane thermal conductivity was 0.0555 W / (m·K), and the electrical conductivity was 266.9 S / cm.

[0092] Example 13 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, the only difference from the preparation steps disclosed in Example 1, is that 8 wt% glycerol (propanetriol) is added during the ultrasonic dispersion process at 40 ℃. The other preparation steps and process parameters are the same, forming an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 50 μm.

[0093] The morphology of the product obtained above, observed under a scanning electron microscope, is as follows: Figure 27 As shown: the product is a nanofiber network with uniform pores.

[0094] The electromagnetic shielding performance, thermal conductivity, and electrical conductivity of the electromagnetic shielding-thermal insulation polymer flexible film were directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 49.85 dB, the average in-plane thermal conductivity was 2.519 W / (m·K), the average inter-plane thermal conductivity was 0.0394 W / (m·K), and the electrical conductivity was 200.5 S / cm.

[0095] Example 14 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, compared with the preparation steps disclosed in Example 12, differs only in that: only 100 mL of electromagnetic shielding-heat insulation substrate-dopant-methanol dispersion was used in the vacuum filtration process; the remaining preparation steps and process parameters are the same, resulting in an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 30 μm. Figure 29 As shown.

[0096] The electromagnetic shielding performance of the electromagnetic shielding-heat insulation polymer flexible film was directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R bands (18~40 GHz) was 42.73 dB.

[0097] Example 15 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, compared with the preparation steps disclosed in Example 12, differs only in that: only 300 mL of electromagnetic shielding-heat insulation substrate-dopant-methanol dispersion was used in the vacuum filtration process; the remaining preparation steps and process parameters are the same, resulting in an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 80 μm. Figure 30 As shown.

[0098] The electromagnetic shielding performance of the electromagnetic shielding-heat insulation polymer flexible film was directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 66.66 dB.

[0099] Example 16 A method for preparing an electromagnetic shielding-heat insulation polymer flexible film, compared with the preparation steps disclosed in Example 12, differs only in that: only 400 mL of electromagnetic shielding-heat insulation substrate-dopant-methanol dispersion was used in the vacuum filtration process; the remaining preparation steps and process parameters are the same, resulting in an electromagnetic shielding-heat insulation polymer flexible film with a thickness of 110 μm. Figure 31 As shown.

[0100] The electromagnetic shielding performance of the electromagnetic shielding-heat insulation polymer flexible film was directly tested, as shown in Table 1. The average electromagnetic shielding effectiveness in the K and R frequency bands (18~40 GHz) was 68.60 dB.

[0101] To further illustrate the superior effects of this invention compared to the prior art, the electromagnetic shielding performance, heat insulation, and electrical conductivity of the products obtained in the above embodiments were measured, and the specific data are shown in Table 1: Table 1. Electromagnetic shielding performance, thermal insulation performance, and electrical conductivity performance of the products obtained in Examples 1-12 of this invention.

[0102] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electromagnetic shielding-heat insulation polymer flexible film, characterized in that, The electromagnetic shielding-heat insulation polymer flexible film is prepared by adding an electromagnetic shielding-heat insulation substrate and a dopant to a solvent, ultrasonically dispersing them to obtain a uniform dispersion, vacuum filtering the dispersion to obtain a solid, and then freeze-drying the solid. The electromagnetic shielding-heat insulation substrate is PEDOT nanofiber; The dopant is one of ethanol, ethylene glycol, propylene glycol, glycerol, methanethiol, 1,2-ethylenedithiol, acetic acid, and oxalic acid. The thickness of the electromagnetic shielding-heat insulation polymer flexible film is 30~110 μm.

2. The electromagnetic shielding-heat insulation polymer flexible film according to claim 1, characterized in that, The solvent is methanol; The concentration of PEDOT nanofibers in the dispersion is 1-5 wt%, and the concentration of dopant is 1-10 wt%.

3. The electromagnetic shielding-heat insulation polymer flexible film according to claim 1, characterized in that, The PEDOT nanofibers were prepared using a solvothermal method, and the specific preparation method is as follows: Sodium dodecyl sulfate and ferric chloride hexahydrate were added to deionized water and stirred in a water bath to form a homogeneous and stable micelle dispersion. Then, 3,4-ethylenedioxythiophene monomer was added dropwise to obtain a mixed solution system. The mixed solution system was reacted in a water bath. After the reaction was completed, the mixture was cooled, centrifuged, washed with deionized water and methanol, and filtered under reduced pressure to finally obtain PEDOT nanofibers.

4. The electromagnetic shielding-heat insulation polymer flexible film according to claim 3, characterized in that, The molar ratio of sodium dodecyl sulfate, 3,4-ethylenedioxythiophene, and ferric chloride hexahydrate is 2.19~8.76 : 1 : 1.095~4.38; The concentration of 3,4-ethylenedioxythiophene in the mixed solution system is 0.034~0.136 mol / L.

5. The electromagnetic shielding-heat insulation polymer flexible film according to claim 3, characterized in that, The temperature of the water bath stirring is 40~60 ℃, and the time is 1~2 h; The temperature of the water bath reaction in the mixed solution system is 40~60 ℃, and the time is 4~8 h.

6. A method for preparing an electromagnetic shielding-heat insulation polymer flexible film as described in any one of claims 1 to 5, characterized in that, The preparation method employs an ultrasonic dispersion-vacuum filtration-freeze-drying film formation process, specifically including the following steps: Electromagnetic shielding-heat insulation substrate and dopant are dispersed in methanol and ultrasonically dispersed to obtain a dispersion. The dispersion is then vacuum filtered through a sand core funnel to the surface of a polytetrafluoroethylene filter membrane to obtain a solid precursor. The solid is clamped with a glass plate and freeze-dried in a vacuum freeze dryer to obtain the electromagnetic shielding-heat insulation polymer flexible membrane.

7. The preparation method according to claim 6, characterized in that, The ultrasonic dispersion temperature is 40 ℃, and the time is 3~6 h; the vacuum filtration pressure is -0.1 MPa; the pore size of the polytetrafluoroethylene filter membrane is 2 μm.

8. The preparation method according to claim 6, characterized in that, The freeze-drying temperature is -80 ℃, the pressure is 100 Pa, and the time is 2~4 h.

9. The application of an electromagnetic shielding-heat insulation polymer flexible film as described in any one of claims 1 to 5 or an electromagnetic shielding-heat insulation polymer flexible film prepared by any one of claims 6 to 8 in electronic and electrical equipment.

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