CN115870200A - A strong hydrophobic and radiation-resistant electromagnetic shielding material - Google Patents

Abstract

The invention provides a strong hydrophobic and radiation-resistant electromagnetic shielding coating, which uses epoxy polysiloxane (PDMS-E) with a molecular weight of 1000 to graft and modify the collagen polypeptide monolayer film G-SDS _6% . The grafting rate of epoxy polysiloxane on the film is 1.7-1.9%, the contact angle is 135-145°, the roughness is 9-11nm, the weight loss rate of ultrasonic radiation is 0.004-0.005%, and the weight loss rate of microwave radiation is 0.004- 0.005%. The strongly hydrophobic and radiation-resistant electromagnetic shielding material provided by the invention has good radiation resistance and strong hydrophobicity, and can be used as an aviation shielding material. Compared with existing shielding materials, it has good electromagnetic shielding, aging resistance and strong hydrophobicity.

Description

A kind of electromagnetic shielding material with strong hydrophobicity and radiation resistance

technical field

The invention belongs to the field of aviation electromagnetic shielding materials, in particular to an electromagnetic shielding material with strong hydrophobicity and radiation resistance.

Background technique

With the rapid development of science and technology, electromagnetic waves are widely used in industries such as aviation, spaceflight, communication and military industry, but the ensuing electromagnetic pollution problem has also attracted more and more attention. Information leakage incidents caused by electromagnetic wave radiation are not uncommon, and science has also proved that electromagnetic radiation can have adverse effects on the human body. In order to provide protection for the human body and electronic devices, electromagnetic shielding materials need to be developed urgently. Electromagnetic shielding is defined as a measure that uses metal and magnetic materials to suppress or weaken the penetration of electromagnetic fields to designated areas, that is, to isolate electromagnetic waves and control the propagation of electromagnetic waves from one area to another.

Common researches on electromagnetic shielding materials include metal materials, foam materials, thin film materials, conductive polymer materials, and composite materials. Studies have found that although conductive coatings have good electrical conductivity, moderate price, and fewer restrictions, they are widely used, but in applications, the film adhesion is not high, and the secondary processing performance is poor. Metal materials are widely used, mainly because of their excellent electrical conductivity and magnetic permeability. Higher electrical conductivity has a good shielding effect on high-impedance electric fields. Higher magnetic permeability is often used for shielding low-frequency magnetic fields. Although most metals have good electromagnetic shielding properties, their high density, easy to corrode, and unsuitable for processing hinder their application. Therefore, the development of an electromagnetic shielding material with low density, excellent electromagnetic shielding performance, easy processing, radiation resistance, corrosion resistance, and recyclability is an important means to control the increasingly serious electromagnetic pollution. If the super-hydrophobic coating is endowed with electromagnetic shielding properties, coupled with the original anti-sticking ability of the super-hydrophobic coating, the scope of outdoor application of the electromagnetic shielding coating will be broadened, and the electrical conductivity of the coating itself can reduce electrostatic adsorption. to prolong the outdoor service life of the superhydrophobic coating.

The main chain of epoxy polysiloxane is Si.0.Si, which is not easy to be decomposed by ultraviolet light and ozone. It has better radiation resistance than other polymer materials, and its chain contains hydrophobic groups, which can avoid hydrophobic After treatment, it is not easy to lose hydrophobicity when subjected to abrasion, and the use of epoxy polysiloxane as a coating can enhance the electromagnetic shielding effect. However, when it is prepared into a coating, there are problems such as thicker film thickness, prone to cracking of the coating, difficult control of the thickness, larger surface roughness of the coating, and poor adhesion.

Contents of the invention

In order to solve the above-mentioned problems existing in the existing electromagnetic shielding materials, the present invention provides an electromagnetic shielding material with strong hydrophobicity and radiation resistance.

In order to achieve the above object, the present invention adopts the following technical solutions:

A strong hydrophobic radiation-resistant electromagnetic shielding coating material is characterized in that the use of molecular weight of 1000 epoxy polysiloxane (PDMS-E) graft modified collagen polypeptide monolayer film G-SDS _6% , The grafting rate of epoxy polysiloxane on the film is 1.7-1.9%, the contact angle is 135-145°, the roughness is 9-11nm, the weight loss rate of ultrasonic radiation is 0.004-0.005%, and the weight loss rate of microwave radiation is 0.004～0.005%.

Ultrasonic radiation weight loss rate is the percent weight reduction of the product under ultrasonic conditions with a power of 650w for 1 hour.

Microwave radiation weight loss rate is the percentage of weight loss when the product is processed in a microwave oven with a voltage of 220V, a frequency of 50Hz, and a power of 700W for 1 hour.

The definition of the grafting rate is:

The change of the molar amount of primary amino groups on the membrane before and after the grafting reaction accounts for the percentage of the molar amount of primary amino groups on the membrane before the grafting reaction.

The change of the molar amount of the primary amino group on the film before and after the grafting reaction can be calculated by (W _D -W ₀ )/1000, which is the molar amount of the successfully grafted epoxypolysiloxane. Wherein, W _D is the quality after grafting epoxy polysiloxane of polypeptide monolayer film, W ₀ is the quality before grafting epoxy polysiloxane of polypeptide monolayer film, 1000 is the relative weight of epoxy polysiloxane Molecular mass. The molecular formula of described epoxy polysiloxane is as follows:

Preferably, the collagen polypeptide monolayer film G-SDS _6% is composed of polypeptide molecules with a molecular weight of (1.48±0.2)×10 ⁵ g/mol, the thickness of the monolayer film is 14.2 nm, and the primary amino groups on the surface of the film The exposure amount was 13.13%, the Zeta potential of the polypeptide monolayer film was 4.907mV; the contact angle of the film was 10°.

Further preferably, the secondary structure of the collagen polypeptide monolayer membrane G-SDS _6% is: α-helix is 40.73±0.1%; β-sheet is 14.97±0.13%; β-turn is 2.55±0.08%; random The coil is 41.75±0.22%.

Further preferably, the preparation method of the polypeptide monolayer film G-SDS _6% is:

(1) Prepare a polypeptide solution at 50°C, then add the surfactant sodium dodecyl sulfate (SDS) to obtain a polypeptide-SDS mixed solution with an SDS concentration of 8.32mmol/L, and keep it warm for later use;

(2) Immerse the base material in the mixed acid solution, rinse until neutral, dry it with nitrogen, and then dry it;

(3) After immersing the dried base material in polyethyleneimine (PEI) aqueous solution for 20-40 minutes, rinse it with water, dry it with nitrogen, and then dry it to obtain a positively ionized base material deposited with PEI;

(4) Immerse the positively ionized substrate material in the polypeptide-SDS mixed solution obtained in step (1), deposit for 8-12 minutes, then pull it in deionized water for 20-25 times, and dry it with high-purity nitrogen, The peptide monolayer film G-SDS _6% was obtained.

Preferably, the concentration of the collagen polypeptide solution in step (1) is 4%wt.

Preferably, the base material in the step (2) is metal, rubber or glass. Further preferably, the base material is titanium or its alloys.

The present invention also provides a preparation method of a strongly hydrophobic and radiation-resistant electromagnetic shielding coating material, which is characterized in that it comprises the following steps:

1) Ultrasonic dispersion of epoxy polysiloxane with a molecular weight of 1000 in sodium carbonate/sodium bicarbonate buffer solution to obtain a mixed solution;

2) Place the collagen polypeptide monolayer membrane G-SDS _6% in the mixed solution for 1-3 hours at a temperature of 48-52°C;

3) Pull the collagen polypeptide monolayer film G-SDS _6% in acetone for more than 10 times to remove unreacted epoxysiloxane, dry it with high-purity nitrogen, and store it in nitrogen.

Preferably, the pH of the sodium carbonate/sodium bicarbonate buffer described in step 1) is 9.6.

Preferably, the concentration of epoxy polysiloxane in the mixed solution in step 1) is 8-12 mmol/L.

The invention also provides the application of a strongly hydrophobic and radiation-resistant electromagnetic shielding material coating in aerospace materials.

An aviation shielding material, characterized in that the surface is coated with the above-mentioned electromagnetic shielding material coating.

Beneficial effects of the present invention:

The strongly hydrophobic and radiation-resistant electromagnetic shielding material provided by the invention has good radiation resistance and strong hydrophobicity, and can be used as an aviation shielding material. Compared with existing shielding materials, it has good electromagnetic shielding, aging resistance and strong hydrophobicity.

The contact angle of the polypeptide monolayer film G-SDS _6% used in the present invention is 10°, and after grafting epoxypolysiloxane with a molecular weight of 1000, the contact angle becomes 145°, which makes the coating have stronger hydrophobic properties, It shows that due to the characteristics of the secondary structure of the polypeptide monolayer film G-SDS _6% , after it is grafted with 1000 molecular weight epoxy polysiloxane, the physical properties of the original coating surface are changed.

Epoxy polysiloxane itself has a certain electromagnetic shielding effect, and the present invention is prepared into a thin film through covalent bonding, the surface grafting is orderly, the flatness is high, and its radiation resistance and stability are enhanced, which is more beneficial as a Electromagnetic shielding material.

Description of drawings

Fig. 1 is the contact angle of different coating samples;

Fig. 2 is the XPS general spectrum of G-SDS _6%wt and the G-SDS _6% -(PDMS-E ₁₀₀₀ ) of embodiment 1;

Fig. 3 is the N1s high-resolution spectrum of G-SDS _6%wt- (PDMS-E ₁₀₀₀ ) of embodiment 1;

Fig. 4 is the Si 2p high-resolution spectrum of G-SDS _6%wt- (PDMS-E ₁₀₀₀ ) of embodiment 1;

Figure 5 is an optical microscope image of G-SDS _6%wt- (PDMS-E ₁₀₀₀ ) of Example 1 after ultrasonic treatment for different times (a, irradiated for 0h, b, irradiated for 0.5h, c irradiated for 1h, magnification 100X) ;

Figure 6 is an optical microscope image of G-SDS _6%wt- (PDMS-E ₁₀₀₀ ) of Example 1 after ultrasonic treatment for different times (a, irradiated for 0h, b, irradiated for 0.5h, c irradiated for 1h, magnification 400X) ;

7 is an optical microscope image of G-SDS6%wt-(PDMS-E1000) of Example 1 after microwave treatment for different times (a, irradiated for 0h, b, irradiated for 0.5h, c irradiated for 1h, magnification 100X);

Figure 8 is an optical microscope image of the G-SDS _6%wt -(PDMS-E ₁₀₀₀ ) sample of Example 1 after microwave treatment for different times (a, irradiated for 0h, b, irradiated for 0.5h, c irradiated for 1h, magnification 400X );

FIG. 9 is a phase diagram of G-SDS 6%wt-(PDMS-E1000) of Example 1. FIG.

Detailed ways

The collagen polypeptide used in the examples of the present invention is a commercially available polypeptide product (AR), its molecular weight is about 5.00×10 ⁴ ~1.80×10 ⁵ g/mol, and the molecular weight of the polypeptide obtained by dialysis is (1.48±0.2) ×10 ⁵ g/mol, 1 g of collagen polypeptide in the present invention contains 5.6×10 ^-4 mol of primary amino groups. All other reagents are commercially available unless otherwise specified.

The preparation method of epoxy polysiloxane used in the present invention can refer to: Zhu C, Xu J, Hou Z, et al. Scale Effect on Interface Reaction between PDMS-E Emulsion Droplets and Gelatin [J]. Langmuir, 2017. The weight average molecular weight of the epoxy polysiloxane used in the present invention is 1000±50.

Example 1

A preparation method of a strongly hydrophobic and radiation-resistant electromagnetic shielding material, comprising the following steps:

S1: Preparation of polypeptide monolayer film G-SDS _6% , please refer to Chinese patent document CN 111840661 A (202010753455.6).

A method for preparing a polypeptide monolayer film, comprising the following steps:

(1) Prepare 50 mL of collagen peptide solution with a concentration of 4% wt: accurately weigh 100 mL of collagen peptide in a three-necked flask, accurately measure deionized water, pour the deionized water into the three-necked flask, and swell at room temperature for 0.5 h. Put the three-neck flask in a water bath at 50±1°C, heat and stir for 2 hours to dissolve it completely, then adjust the pH of the solution to 10.00±0.02 with 2mol/L sodium hydroxide, and stabilize it in the water bath for 0.5 hours.

(2) Add the surfactant SDS to the above collagen polypeptide solution to obtain a collagen polypeptide-SDS mixed solution, the concentration of SDS in the mixed solution is 8.32 (6%wt) mmol/L; stabilize it in a water bath for 6h and set aside.

(3) Cut a number of square titanium sheets with a size of 1cm×1cm×1mm, use metallographic sandpaper to polish and polish in order of 800, 1500, 3000, 5000, and 7000 meshes, and then use deionized water, absolute ethanol, and acetone to ultrasonically Clean the titanium sheets for 15 minutes each, then blow dry them with high-purity nitrogen, and then dry them in an oven at 60°C for 12 hours for later use. Prepare a mixed acid solution of 30% H ₂ O ₂ and 98% H ₂ SO ₄ with a volume ratio of 1:1. After cooling to room temperature, treat the above-mentioned treated titanium sheet with mixed acid for 1 hour, then rinse it with tap water until neutral, and then Wash with deionized water for 5 times, and finally blow dry with high-purity nitrogen, and then dry in an oven at 60°C for 12 hours for later use.

(4) Prepare a 1mg/mL PEI polyethyleneimine aqueous solution, treat the above-mentioned acid-etched titanium sheet with PEI solution at room temperature for 0.5h, and then wash it with deionized water for 5 times to remove the weakly bonded charge, and finally use high After being blown dry with pure nitrogen, it was dried in an oven at 60°C for 12 hours before use. Put the positively ionized titanium sheet into the deposition box, pour the peptide solutions of different systems prepared above into the deposition box, deposit at 50°C for 10 min, and then pull it in deionized water 20 times, use high Blow dry with pure nitrogen and store in nitrogen. The resulting polypeptide monolayer was labeled as G-SDS _6% .

S2: Preparation of strong hydrophobic and radiation-resistant electromagnetic shielding material G-SDS _6% - (PDMS-E1000),

1) Sonicate epoxy polysiloxane with a molecular weight of 1000 for 15 minutes, and disperse it in sodium carbonate/sodium bicarbonate buffer (pH=9.6) to obtain a mixed solution; the concentration of epoxy polysiloxane in the mixed solution is 0.0112mol /L.

2) Place the collagen polypeptide monolayer membrane G-SDS _6% in the above mixed solution for 2 hours at a temperature of 50°C;

3) The collagen polypeptide monolayer film G-SDS _6% was pulled 10 times in acetone to remove unreacted epoxysiloxane, dried with high-purity nitrogen and stored in nitrogen. Prepare multiple samples under the same conditions at the same time, although there will be slight differences in the grafting rate, but it will not affect its own performance and use environment, and it is within the error range. The grafting rate of epoxy polysiloxane on the obtained G-SDS _6% -(PDMS-E ₁₀₀₀ ) film was 1.82%, the contact angle was 145°, and the roughness was 10.93nm.

Example 2

A method for preparing a strongly hydrophobic and radiation-resistant electromagnetic shielding material, comprising the following steps: the difference from Example 1 is that the concentration of epoxy polysiloxane in the mixed solution is 0.00885 mol/L.

The grafting ratio of the obtained G-SDS _6%wt -(PDMS-E ₁₀₀₀ ) was 1.71%, the contact angle was 138°, and the roughness was 9.54nm.

Example 3

A method for preparing a strongly hydrophobic and radiation-resistant electromagnetic shielding material, comprising the following steps: the difference from Example 1 is that the grafting time is changed to 1 h.

The grafting ratio of the obtained G-SDS _6%wt -(PDMS-E ₁₀₀₀ ) material was 1.73%, the contact angle was 135°, and the roughness was 10.22nm.

Comparative example 1

A coating for electromagnetic shielding materials, the difference from Example 1 is that the molecular weight of epoxy polysiloxane is 500, and the concentration of epoxy polysiloxane is 0.0242mol/L. The obtained coating material is denoted as G-SDS _6%wt- (PDMS-E ₅₀₀ ), the graft rate of this product is 0.101%, the contact angle is 120.91°, and the roughness is 10.48nm.

Comparative example 2

A coating material, add 5g of gelatin, add water, stir and heat to 50°C, after the gelatin is completely dissolved, add sodium hydroxide to adjust the reaction pH to 10.0 to obtain a gelatin solution with a mass concentration of 5%, then add lauryl sulfate Sodium (SDS) was used as an emulsifier, and the stirring was continued until completely dissolved, and the concentration of SDS in the solution was 8.32 (6% wt) mmol/L. Then add 56 mg epoxy polysiloxane (Mw=1000) continuously or in batches, react for 24 hours, stop stirring and heating to obtain epoxy polysiloxane modified gelatin solution. The positively ionized titanium sheet was placed in solution 2, deposited at 50°C for 10 min, then pulled in acetone 20 times, dried with high-purity nitrogen and stored in nitrogen to obtain a coating. The contact angle of this coating was 118.5°.

1. Determination of surface wettability of aeronautical electromagnetic shielding coatings

The water contact angle (CA) of the film samples was measured at room temperature using a DSA-100 optical contact angle meter (Kruss, Germany). 2 mL of deionized water was dropped onto the sample using an automatic dispensing controller, and the CA was automatically determined using the Laplace-Young fitting algorithm. The average CA value was obtained by measuring samples at five different positions, and the images were taken with a digital camera (Sony Co., Ltd., Japan). The results are shown in Figure 1.

2. Elemental analysis of the membrane surface after grafting

XPS can clearly give the composition information on the surface of the film, and can also analyze the chemical state of the elements with high resolution. The size of the water contact angle gives an intuitive impression of the hydrophilicity and hydrophobicity of the sample, and the size of the contact angle is closely related to the surface composition of the film. The chemical composition of G-SDS _{6% wt} - (PDMS-E ₁₀₀₀ ) was directly analyzed using XPS (ESCALABXi+, USA).

Figure 2 shows the change of surface elements before and after G-SDS _6%wt grafted with PDMS-E1000, Blank refers to: G-SDS _6%wt (Blank), G-M1000 refers to G-SDS _6%wt - (PDMS-E ₁₀₀₀ ), the peak at 401eV is -NH ₂ . It can be seen that before the grafting reaction, the polypeptide monolayer film sample contains a certain amount of N elements, and after the grafting of epoxy polysiloxane, the increase of Si elements and the decrease of N elements can be clearly seen.

3. Radiation resistance performance test

Place the sample G-SDS _6%wt -(PDMS-E ₁₀₀₀ ) under ultrasonic and microwave conditions for 0h, 0.5h, 1h, and then use an optical microscope to take pictures at 100X and 400X for comparison, and finally use a quartz crystal microbalance Accurately weigh the mass.

(1) Ultrasonic treatment

Sample (embodiment 1, comparative example 1, comparative example 2) is placed in the empty beaker of 25mL, is placed in ultrasonic cleaner (KQ-250B type ultrasonic cleaner, Kunshan Ultrasonic Instrument Co., Ltd., power supply voltage 220v, capacity 10mL , power 650W) under 0h, 0.5h, 1h processing, the solvent in the ultrasonic machine is tap water, then use an optical microscope to take pictures at 100X and 400X for comparison, and finally use a quartz crystal microbalance to (embodiment 1, comparative example 1 , Comparative example 2) mass is accurately weighed.

Table 1. The mass change of the coating after ultrasonic treatment for different times

It can be seen from the above optical microscope images that the surface of the coating after ultrasonic treatment has little change and the surface is uniform. The quality of the sample after ultrasonic treatment was accurately weighed by a quartz crystal microbalance, from Table 1 It can be seen that the mass change of Example 1 is very small, and the mass change of Comparative Example 1 and Comparative Example 2 is relatively large before and after treatment, which can further reflect the effect on G(SDS _6%wt )-(PDMS-E ₁₀₀₀ ) coating after ultrasonic treatment Layers have little effect.

(2) Microwave treatment

Samples (Example 1, Comparative Example 1, Comparative Example 2) are placed in a 25mL empty beaker, and then placed in a microwave oven (Midea Jiangsu Meidixia Specialty Store, model: M1-L202B, rated voltage: 220V, rated frequency: 50Hz , microwave power is 700W) and carry out 0h, 0.5h, 1h treatment, then take pictures with optical microscope under 100X, 400X for comparison, finally use quartz crystal microbalance to (embodiment 1, comparative example 1, comparative example 2) quality Weigh accurately.

Table 2. Mass change table of coating after different microwave treatment time

It can be seen from the above optical microscope images that the surface of the coating after microwave treatment has little change and the surface is uniform. The quality of the sample after microwave treatment was accurately weighed by a quartz crystal microbalance. From Table 2 It can be seen that the mass change of Example 1 is very small, and the mass change of Comparative Example 1 and Comparative Example 2 is relatively large before and after treatment, which can further reflect that G(SDS _6%wt )-(PDMS-E ₁₀₀₀ ) coated Layers have little effect. It can be seen from the above results that the present invention can not only control the thickness of the film at the nanometer level, but also improve its radiation resistance by preparing gelatin into a polypeptide monolayer film and then grafting it with epoxy polysiloxane. . It shows that compared with the gelatin polymer, the structure and performance of the polypeptide monolayer membrane have changed to a certain extent. After grafting with the quaternary ammonium salt, the performance of the membrane has an unexpected change. In addition, the grafting rate of gelatin is not easy to control after first modifying the gelatin, and there are ungrafted epoxy polysiloxanes in the obtained coating, which has great influence on the film thickness, adhesion stability, chemical stability, etc. have adverse effects.

4. Phase diagram test

In an atomic force microscope (AFM) system, the interaction force between a tiny probe and a measured object is used to represent the physical properties of the measured object surface. The present invention uses tapping mode AFM to characterize the phase diagram of the sample.

The phase diagram can provide the shape, size and distribution of different substances on the surface of the sample. As can be seen from the above figure, the phase diagram shows that the distribution of light and dark areas of the coating is relatively uniform, which is due to the epoxy polysiloxane There is a strong interaction between the alkane and the collagen polypeptide molecular chain, and the collagen polypeptide molecular chain has a binding effect on the chain break of the epoxy polysiloxane, which can limit the aggregation of the epoxy polysiloxane, so that the epoxy polysiloxane Oxane can be evenly distributed. It can be seen from the phase diagram that epoxy polysiloxane can be evenly distributed on the coating surface.

As can be seen from the above results, the present invention is prepared into a polypeptide monolayer film by gelatin in the presence of 8.32mmol/L sodium ditetraalkyl sulfate (SDS), and then with molecular weight is 1000 epoxy polysiloxane Carrying out the grafting reaction can not only control the thickness of the film at the nanometer level, but also improve the radiation resistance of the material. It shows that compared with the gelatin polymer, the structure and performance of the polypeptide monolayer film have changed to a certain extent. After it is grafted with epoxy polysiloxane, the performance of the film has an unexpected change. In addition, it is not easy to control the grafting rate of gelatin modified first and then grafted. There are ungrafted epoxy polysiloxanes in the obtained coating, and some of them are easy to dissolve during the elution process, which affects the stability of the film. That is, the adhesion performance is affected, and the undissolved part is easy to dissolve and ooze out during subsequent use, and has poor chemical stability.

Claims (10)

1. a strong hydrophobic radiation-resistant electromagnetic shielding coating, characterized in that the use of molecular weight is 1000 epoxy polysiloxane (PDMS-E) to carry out graft modification of collagen polypeptide monolayer film G-SDS _6% , the grafting rate of epoxy polysiloxane on the film is 1.7-1.9%, the contact angle is 135-145°, the roughness is 9-11nm, the weight loss rate of ultrasonic radiation is 0.004-0.005%, and the weight loss rate of microwave radiation 0.004 to 0.005%. 2. Electromagnetic shielding coating according to claim 1, is characterized in that, the weight loss rate of ultrasonic radiation is the percentage of weight reduction that product is processed under the ultrasonic condition of 650w for 1 hour; The weight loss rate of microwave radiation is product at voltage 220V, Percentage weight loss after 1 hour treatment in a microwave oven with a frequency of 50 Hz. Described grafting ratio: before and after the grafting reaction, the change of the primary amino molar weight on the membrane accounts for the percentage of the primary amino molar weight on the membrane before the grafting reaction; The change of the molar amount of the primary amino group on the film before and after the grafting reaction can be calculated by (W _D -W ₀ )/1000, which is the molar amount of the successfully grafted epoxypolysiloxane. Among them, W _D is the mass of the polypeptide monolayer film grafted with epoxy polysiloxane, and W ₀ is the mass of the polypeptide monolayer film grafted with epoxy polysiloxane. 3. electromagnetic shielding coating according to claim 1, is characterized in that, the molecular formula of described epoxy polysiloxane is as follows:

4. The electromagnetic shielding coating according to claim 1, characterized in that, the collagen polypeptide monolayer film G-SDS _6% is composed of polypeptide molecules with a molecular weight of (1.48±0.2)×10 ⁵ g/mol , the thickness of the monolayer film is 14.2nm, the exposure of primary amino groups on the surface of the film is 13.13%, the Zeta potential of the polypeptide monolayer film is 4.907mV; the contact angle of the film is 10°. Further preferably, the secondary structure of the collagen polypeptide monolayer membrane G-SDS _6% is: α-helix is 40.73±0.1%; β-sheet is 14.97±0.13%; β-turn is 2.55±0.08%; random The coil is 41.75±0.22%. 5. electromagnetic shielding coating according to claim 1, is characterized in that, the preparation method of described polypeptide monolayer film G-SDS _6% is: (1) Prepare a polypeptide solution at 50°C, then add the surfactant sodium dodecyl sulfate (SDS) to obtain a polypeptide-SDS mixed solution with an SDS concentration of 8.32mmol/L, and keep it warm for later use; (2) Immerse the base material in the mixed acid solution, rinse until neutral, dry it with nitrogen, and then dry it; (3) After immersing the dried base material in polyethyleneimine (PEI) aqueous solution for 20-40 minutes, rinse it with water, dry it with nitrogen, and then dry it to obtain a positively ionized base material deposited with PEI; (4) Immerse the positively ionized substrate material in the polypeptide-SDS mixed solution obtained in step (1), deposit for 8-12 minutes, then pull it in deionized water for 20-25 times, and dry it with high-purity nitrogen, The peptide monolayer film G-SDS _6% was obtained. 6. electromagnetic shielding coating according to claim 5, is characterized in that, the concentration of collagen polypeptide solution is 4%wt in the step (1); In the step (2), the base material is metal, rubber or glass; preferably, the base material is titanium or its alloy. 7. The preparation method of the strongly hydrophobic radiation-resistant electromagnetic shielding coating described in any one of claims 1 to 6, characterized in that it comprises the following steps: 1) Ultrasonic dispersion of epoxy polysiloxane with a molecular weight of 1000 in sodium carbonate/sodium bicarbonate buffer solution to obtain a mixed solution; 2) Place the collagen polypeptide monolayer membrane G-SDS _6% in the mixed solution for 1-3 hours at a temperature of 48-52°C; 3) Pull the collagen polypeptide monolayer film G-SDS _6% in acetone for more than 10 times to remove unreacted epoxysiloxane, dry it with high-purity nitrogen, and store it in nitrogen. 8. the preparation method of electromagnetic shielding coating according to claim 7 is characterized in that, the pH described in step 1) in sodium carbonate/sodium bicarbonate buffer is 9.6; In the mixed solution, epoxy polysilicon The concentration of oxane is 8-12mmol/L. 9. The application of the strongly hydrophobic and radiation-resistant electromagnetic shielding coating according to any one of claims 1 to 6 in aerospace materials. 10. An aviation shielding material, characterized in that the surface of the material is coated with the coating according to any one of claims 1-6.

Images