Radio frequency perfluorooctanoic acid sensor suitable for marine environment

Abstract

The invention discloses a radio frequency perfluorooctanoic acid sensor suitable for a marine environment, the radio frequency perfluorooctanoic acid sensor comprises a boron-doped diamond radiation patch, a dielectric substrate and a grounding plate, the boron-doped diamond radiation patch, the dielectric substrate and the grounding plate are arranged in parallel, the boron-doped diamond radiation patch is used as a radiator, and the dielectric substrate is used as the grounding plate. A groove for embedding the boron-doped diamond radiation patch is formed on one surface of the dielectric substrate, the shape of the groove is matched with that of the boron-doped diamond radiation patch, and the other surface of the dielectric substrate is provided with the grounding plate. The radio frequency antenna perfluorooctanoic acid sensor is used for detecting the concentration of perfluorooctanoic acid. The boron-doped diamond and the polydimethylsiloxane are adopted as sensitive film materials of the radio frequency antenna perfluorooctanoic acid sensor, perfluorooctanoic acid in the ocean can be efficiently and accurately detected, the detection sensitivity is remarkably improved, and the radio frequency antenna perfluorooctanoic acid sensor has excellent anti-interference capacity.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental monitoring, and particularly relates to a radio frequency antenna perfluorooctanoic acid sensor. Background Art

[0002] With the rapid development of industrialization, the concentration of persistent organic pollutants in the environment has gradually increased. Among them, perfluorooctanoic acid (PFOA) - type pollutants have become a globally concerned persistent organic pollutant (POPs) due to their strong chemical stability, difficulty in natural degradation, and bioaccumulation in organisms. Research shows that the ocean, as an important part of the earth's ecosystem, has been severely affected by PFOA - type pollutants. PFOA - type pollutants usually exist in the form of small particle dust, not only distributed on the sea surface and in seawater, but also polluting marine air in the form of aerosols, further eroding marine organisms and plant communities. This kind of pollution not only endangers the health of the marine ecosystem, but also threatens the safety of the global food chain and poses a potential threat to human health.

[0003] Facing the widespread distribution and hidden threats of PFOA - type pollutants, the development of highly sensitive sensors is of great significance for protecting the marine ecosystem, evaluating pollution diffusion, and formulating pollution control measures. The existing antenna sensors have a detection limit for PFOA of about 1 - 5 ppt and cannot detect lower concentrations of PFOA. Therefore, it is particularly necessary to develop a sensor suitable for the marine environment, especially a sensing system that can accurately sense changes in PFOA concentration and detect low - concentration PFOA. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a radio frequency antenna perfluorooctanoic acid sensor (radio frequency perfluorooctanoic acid sensor), which combines an integrated radio frequency antenna and a boron - doped diamond film.

[0005] Another object of the present invention is to provide a preparation method of the above - mentioned radio frequency antenna perfluorooctanoic acid sensor.

[0006] Another object of the present invention is to provide the use of the above - mentioned radio frequency antenna perfluorooctanoic acid sensor in detecting perfluorooctanoic acid (PFOA). The radio frequency antenna perfluorooctanoic acid sensor, as a sensor device for marine buoys, is suitable for marine pollution monitoring, realizes high - sensitivity monitoring of PFOA pollutants, and can operate stably under long - term high - humidity and complex marine conditions.

[0007] The object of the present invention is achieved by the following technical solutions.

[0008] A boron-doped diamond radiation patch, comprising: a radiation patch and a boron-doped diamond film loaded on the radiation patch, wherein the thickness of the boron-doped diamond film is 1.5 to 4.5 μm (preferably 1.809 to 4.079 μm).

[0009] In the above technical solution, the radiation patch is a tantalum sheet.

[0010] A preparation method of a boron-doped diamond radiation patch, comprising: preparing a boron-doped diamond film on a radiation patch to obtain a boron-doped diamond radiation patch.

[0011] The preparation method of the above boron-doped diamond radiation patch comprises the following steps:

[0012] Step 1, immersing the radiation patch in a diamond nanoparticle dispersion, ultrasonic cleaning, washing, and drying to obtain a radiation patch loaded with diamond nanoparticles;

[0013] In Step 1, the diamond nanoparticle dispersion is a mixture of diamond nanoparticles and absolute ethanol, and the concentration of diamond nanoparticles in the diamond nanoparticle dispersion is 2 to 3 mg / mL -1 .

[0014] In Step 1, the power of ultrasonic treatment is 600 to 650 W, and the time of ultrasonic treatment is 60 to 70 minutes.

[0015] In Step 1, the drying is carried out by irradiating with an infrared light source of 275 to 300 W for 3 to 4 minutes.

[0016] In Step 1, the cleaning includes: successively ultrasonic cleaning in absolute ethanol and water.

[0017] Step 2, placing the radiation patch loaded with diamond nanoparticles on the sample stage of the vacuum deposition chamber in the CVD system, sealing the vacuum deposition chamber, evacuating the vacuum deposition chamber, introducing hydrogen and methane into the vacuum deposition chamber. When the pressure in the vacuum deposition chamber reaches 11 to 12 Torr, applying an alternating current of 110 to 120 A to the alternating current filament in the vacuum deposition chamber. When the pressure in the vacuum deposition chamber reaches 37.5 to 38.5 Torr, continuing to apply an alternating current of 110 to 120 A to the alternating current filament in the vacuum deposition chamber at this pressure (37.5 to 38.5 Torr) for 30 to 35 min;

[0018] In Step 2, the voltage of the alternating current filament when applying the alternating current is 10 to 11 V.

[0019] In Step 2, the flow rate of hydrogen introduced is 300 to 310 mL / min, and the flow rate of methane introduced is 17 to 18 mL / min.

[0020] In step 2, the AC filament is a tantalum wire.

[0021] In step 3, hydrogen and methane are continuously introduced into the vacuum deposition chamber, the pressure in the vacuum deposition chamber is maintained at 37.5 - 38.5 Torr, a boron source is introduced into the vacuum deposition chamber, a DC bias voltage is applied between the sample stage and the AC filament, and an alternating current is applied to the AC filament, so that the DC bias voltage and the alternating current jointly make the temperature of the environment where the radiation patch is located reach 850 - 900 °C, and it is maintained under this condition for 1.5 - 2 hours until a boron-doped diamond film is grown on the radiation patch to obtain a boron-doped diamond radiation patch.

[0022] In step 3, the boron source is a mixture of trimethyl borate (B(OCH 3 ) 3 ) and ethanol. After the boron source is atomized, it is introduced into the vacuum deposition chamber through a carrier gas, and the flow rate of the carrier gas is 12 - 36 mL min -1 .

[0023] In the above technical solution, by volume fraction, the ratio of trimethyl borate (B(OCH 3 ) 3 ) to ethanol is (3 - 3.5):1.

[0024] In step 3, the flow rate of hydrogen introduced is 300 - 310 mL / min, and the flow rate of methane introduced is 6 - 6.5 mLmin -1 .

[0025] In step 3, the alternating current applied to the AC filament is 110 - 120 A, and the voltage of the AC filament when the alternating current is applied is 10 - 11 V.

[0026] In step 3, the DC bias voltage applied between the sample stage and the AC filament is 190 - 200 V.

[0027] In the above technical solution, the carrier gas is hydrogen.

[0028] A perfluorooctanoic acid sensor for a radio frequency antenna includes: a boron-doped diamond radiation patch, a dielectric substrate, and a ground plane. The boron-doped diamond radiation patch, the dielectric substrate, and the ground plane are arranged in parallel. The boron-doped diamond radiation patch serves as a radiator. A groove for embedding the boron-doped diamond radiation patch is formed on one surface of the dielectric substrate, and the shape of the groove is adapted to that of the boron-doped diamond radiation patch. The ground plane is arranged on the other surface of the dielectric substrate;

[0029] The radiation patch includes: a T-shaped patch, a fourth rectangular patch, a fifth rectangular patch, a sixth rectangular patch, a seventh rectangular patch, an eighth rectangular patch, and a ninth rectangular patch, where:

[0030] The T-shaped patch includes: a first rectangular patch, a second rectangular patch, a first square patch, and a third rectangular patch. The length direction of the first rectangular patch is set horizontally, the length directions of the second rectangular patch and the third rectangular patch are set vertically, the bottom edge of the first square patch is set horizontally, the bottom edge of the second rectangular patch is connected to the center position of the top edge of the first rectangular patch, the top edge of the second rectangular patch is connected to the bottom edge of the first square patch, and the top edge of the first square patch is connected to the bottom edge of the third rectangular patch;

[0031] The length direction of the fourth rectangular patch is set horizontally, and the right edge of the third rectangular patch is connected to the left edge of the fourth rectangular patch; the length directions of the fifth rectangular patch, the seventh rectangular patch, and the ninth rectangular patch are set vertically, the length directions of the sixth rectangular patch and the eighth rectangular patch are set horizontally, the right edge of the fourth rectangular patch is connected to the left edge of the fifth rectangular patch, the right edge of the fifth rectangular patch is connected to the left edge of the sixth rectangular patch, the right edge of the sixth rectangular patch is connected to the left edge of the seventh rectangular patch, the right edge of the seventh rectangular patch is connected to the left edge of the eighth rectangular patch, and the right edge of the eighth rectangular patch is connected to the left edge of the ninth rectangular patch. The top edges of the third rectangular patch, the fourth rectangular patch, the fifth rectangular patch, the seventh rectangular patch, the eighth rectangular patch, and the ninth rectangular patch are located on the same straight line, and the bottom edges of the fifth rectangular patch, the sixth rectangular patch, the seventh rectangular patch, and the ninth rectangular patch are located on the same straight line.

[0032] In the above technical solution, the ground plane is a copper foil.

[0033] Use of the above radio frequency antenna perfluorooctanoic acid sensor in detecting perfluorooctanoic acid (PFOA).

[0034] In the above technical solution, the method for the above radio frequency antenna perfluorooctanoic acid sensor to detect perfluorooctanoic acid (PFOA) includes:

[0035] S1, obtaining the S 11 curve of the radio frequency antenna perfluorooctanoic acid sensor at different concentrations of perfluorooctanoic acid (PFOA) through testing; obtaining a frequency offset Δf according to each S 11 curve;

[0036] S2, taking the frequency offset Δf as the ordinate and the concentration of perfluorooctanoic acid (PFOA) as the abscissa to establish a coordinate system, substituting the frequency offset Δf and the concentration of perfluorooctanoic acid (PFOA) obtained at different concentrations of perfluorooctanoic acid (PFOA) in S1 into the coordinate system and performing fitting to obtain at least one straight line, and obtaining a linear equation for each straight line;

[0037] S3. Obtain S of the radio frequency antenna perfluorooctanoic acid sensor in the environment to be measured. 11 Curve, obtain the frequency offset Δf of the environment to be measured, and substitute the frequency offset Δf of the environment to be measured into the linear equation of S2 to calculate the concentration of perfluorooctanoic acid (PFOA) in the environment to be measured.

[0038] In the above technical solution, the frequency value corresponding to the trough of each S 11 Curve is f', and the frequency offset Δf = f' - 2.45 (unit: GHz).

[0039] In the above technical solution, the environment to be measured is a gas phase, a liquid phase or a gas-liquid mixed phase.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] The present invention uses boron-doped diamond (BDD) and polydimethylsiloxane (PDMS) as the sensitive film materials of the radio frequency antenna perfluorooctanoic acid sensor, which can efficiently and accurately detect perfluorooctanoic acid (PFOA) pollutants in the ocean, significantly improving the detection sensitivity. Moreover, the radio frequency antenna perfluorooctanoic acid sensor of the present invention has excellent anti-interference ability and can effectively cope with the influence of external factors such as electromagnetic interference, tidal fluctuations and humidity changes in the ocean environment on the sensing signal. Description of the Drawings

[0042] Figure 1 Is the appearance of the boron-doped diamond radiation patch;

[0043] Figure 2 Is the surface SEM image of the boron-doped diamond radiation patches prepared in Examples 1-5 and the radiation patch loaded with diamond film obtained in Example 7. Among them, a is the radiation patch loaded with diamond film in Example 7, and b-f are the boron-doped diamond radiation patches prepared in Examples 1-5 in sequence;

[0044] Figure 3 Is the cross-sectional SEM image of the boron-doped diamond radiation patches prepared in Examples 1-5 and the radiation patch loaded with diamond film obtained in Example 7. Among them, a is the radiation patch loaded with diamond film in Example 7, and b-f are the boron-doped diamond radiation patches prepared in Examples 1-5 in sequence;

[0045] Figure 4 Is the schematic diagram of the assembly process of the radio frequency antenna perfluorooctanoic acid sensor;

[0046] Figure 5 Is the physical photo of the radio frequency antenna perfluorooctanoic acid sensor;

[0047] Figure 6Rear view of (a) the radio frequency antenna perfluorooctanoic acid sensor and (b) three-dimensional structure diagram of the dielectric substrate;

[0048] Figure 7 S obtained from the PFOA aerogel static response test on the radio frequency antenna perfluorooctanoic acid sensor of Example 4 11 Curve;

[0049] Figure 8 Relationship between the frequency offset Δf and the concentration of perfluorooctanoic acid (PFOA) in a closed environment;

[0050] Figure 9 Dimension diagram of the radiation patch;

[0051] Figure 10 Relationship between the frequency offset Δf and the concentration of perfluorooctanoic acid (PFOA) in the concentration range of 0 - 10 ppt;

[0052] Figure 11 Sensitivity of the radio frequency antenna perfluorooctanoic acid sensors of Examples 1 - 7;

[0053] Figure 12 Results of the anti-interference test;

[0054] Figure 13 Schematic structural diagram of the radiation patch. Specific embodiments

[0055] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0056] CVD system: Hot filament CVD and diamond co-deposition system, Shenyang Scientific Instruments Co., Ltd., Chinese Academy of Sciences; In the CVD system, the AC filament is 5 hooked tantalum wires, each tantalum wire has a diameter of 0.6 mm and a straightened length of 185 mm. Use springs to hang the 5 tantalum wires on the copper rack in the vacuum deposition chamber to ensure that the tantalum wires are suspended directly above the sample stage and remain horizontal.

[0057] In the following embodiments, the radiation patch needs to be pretreated before use. The pretreatment includes: first, use 240-mesh fine sandpaper (Xili brand sandpaper 21*27 cm) to polish the surface of the radiation patch (remove the oxide layer and produce scratches on the surface), wipe it with a dust-free cloth to remove the powder ground off, and then ultrasonically clean the radiation patch in ultrapure water and absolute ethanol for 10 minutes each (the power of ultrasonic is 600 W).

[0058] Use HFSS in Ansys Electronics Desktop software to design the size of the radiation patch, perform simulation and optimization, and design a radio frequency antenna perfluorooctanoic acid sensor with an operating frequency of about 2.45 GHz (optimize and adjust the size parameters of the radiation patch to achieve the best resonance effect of the radio frequency antenna perfluorooctanoic acid sensor near 2.45 GHz). Laser cut the tantalum sheet according to the size of the designed radiation patch to obtain the radiation patch.

[0059] In the following embodiments, the method for obtaining the dielectric substrate (50*50 mm) includes: preparing a PDMS prepolymer and a curing agent with a mass ratio of 10:1 (Dow Corning PDMS polydimethylsiloxane, model: 184), mixing the PDMS prepolymer and the curing agent, stirring well until only tiny bubbles exist, then pouring them into a mold, placing the mold in a vacuum drying oven at 25°C for 40 minutes until the bubbles completely disappear, and then drying at 70°C for 50 minutes until the PDMS is completely cured, demolding to obtain the dielectric substrate. The material of the mold is ABS (white photosensitive resin).

[0060] Examples 1 - 5

[0061] As Figure 4 、 Figure 5 、 Figure 6 shown in (a) of Figure 6 and (b) of Figure 4 , the radio frequency antenna perfluorooctanoic acid sensor includes: a boron-doped diamond radiation patch, a dielectric substrate, and a ground plane (copper foil). The boron-doped diamond radiation patch includes: a radiation patch and a boron-doped diamond thin film loaded on the radiation patch. The boron-doped diamond radiation patch, the dielectric substrate, and the ground plane are arranged in parallel. The boron-doped diamond radiation patch serves as a radiator. A groove for embedding the boron-doped diamond radiation patch is formed on one side of the dielectric substrate. The shape of the groove is adapted to the boron-doped diamond radiation patch. A ground plane is arranged on the other side of the dielectric substrate. The SMA head ( Figure 4 "radio frequency connector" in

[0062] connects the boron-doped diamond radiation patch and the ground plane to form a radio frequency antenna perfluorooctanoic acid sensor.

[0062] The preparation method of the boron-doped diamond radiation patch includes the following steps:

[0063] Step 1, immerse the radiation patch (tantalum sheet) in the diamond nanoparticle dispersion liquid, ultrasonicate for 60 minutes at a power of 600 W, clean (ultrasonicate in absolute ethanol and water for 10 minutes each in sequence, with a power of 600 W for ultrasonication), dry (irradiate under a 275 W infrared light source for 3 minutes) to obtain a radiation patch loaded with diamond nanoparticles. Among them, the diamond nanoparticle dispersion liquid is a mixture of diamond nanoparticles and absolute ethanol, and the concentration of diamond nanoparticles in the diamond nanoparticle dispersion liquid is 2 mg mL -1 ;

[0064] Step 2: Place the radiation patch loaded with diamond nanoparticles in the center of the sample stage of the vacuum deposition chamber in the CVD system, adjust the height of the sample stage so that the vertical distance between the radiation patch loaded with diamond nanoparticles and the AC filament is 50 mm, seal the vacuum deposition chamber, open the exhaust valve of the CVD system, evacuate the vacuum deposition chamber, and repeatedly purge the vacuum deposition chamber with hydrogen three times until the pressure in the vacuum deposition chamber drops to 5 Pa. When the pressure drops to 5 Pa again, introduce hydrogen and methane into the vacuum deposition chamber (the flow rate of hydrogen is 300 mL / min, the flow rate of methane is 18 mL / min), when the pressure in the vacuum deposition chamber reaches 12 Torr, start the AC filament power supply, apply 120A of AC power to the AC filament in the vacuum deposition chamber (the voltage of the AC filament is 10V when the AC power is applied), adjust the exhaust valve, and when the pressure in the vacuum deposition chamber reaches 37.5 Torr, continue to apply 120A of AC power to the AC filament in the vacuum deposition chamber (the voltage of the AC filament is 10V when the AC power is applied) for 30 minutes under the pressure to carry out carbonization;

[0065] Step 3: Adjust the height of the sample stage so that the vertical distance between the carbonized diamond nanoparticle-loaded radiation patch and the AC filament is 8 mm, and keep the flow rate of hydrogen into the vacuum deposition chamber at 300 mL min. -1 The flow rate of methane into the vacuum deposition chamber was adjusted to 6 mL min -1 , while maintaining the pressure in the vacuum deposition chamber at 37.5 Torr, introducing a boron source into the vacuum deposition chamber, applying a DC bias of 200 V between the sample stage and the AC filament, applying an AC current of 115 A to the AC filament (the voltage of the AC filament is 10.5 V when the AC current is applied), so that the DC bias and the AC current together make the temperature of the environment where the radiation patch is located reach 850° C., and maintaining this condition for 2 hours to grow a boron-doped diamond film on the radiation patch to obtain a boron-doped diamond radiation patch, wherein the boron source is trimethyl borate (B(OCH 3 ) 3 ) and ethanol, by volume, trimethyl borate (B(OCH 3 ) 3 The ratio of ) to ethanol is 3:1. After the boron source is atomized, it is introduced into the vacuum deposition chamber through the carrier gas. The carrier gas is (another) hydrogen, and the flow rate of the carrier gas is X mL min -1 The X values ​​are shown in Table 1.

[0066] Table 1

[0067] Boron-doped diamond radiation patch <![CDATA[X(mL min -1 )]]> Example 1 12 Example 2 18 Example 3 24 Example 4 30 Example 5 36

[0068] like Figure 13As shown in the figure, the radiation patch includes: a T-shaped patch, a fourth rectangular patch, a fifth rectangular patch, a sixth rectangular patch, a seventh rectangular patch, an eighth rectangular patch, and a ninth rectangular patch, where:

[0069] The T-shaped patch includes: a first rectangular patch, a second rectangular patch, a first square patch, and a third rectangular patch. The length direction of the first rectangular patch is set horizontally, the length directions of the second rectangular patch and the third rectangular patch are set vertically, the bottom edge of the first square patch is set horizontally, the bottom edge of the second rectangular patch is connected to the center position of the top edge of the first rectangular patch, the top edge of the second rectangular patch is connected to the bottom edge of the first square patch, and the top edge of the first square patch is connected to the bottom edge of the third rectangular patch;

[0070] The length direction of the fourth rectangular patch is set horizontally, and the right edge of the third rectangular patch is connected to the left edge of the fourth rectangular patch; the length directions of the fifth rectangular patch, the seventh rectangular patch, and the ninth rectangular patch are set vertically, the length directions of the sixth rectangular patch and the eighth rectangular patch are set horizontally, the right edge of the fourth rectangular patch is connected to the left edge of the fifth rectangular patch, the right edge of the fifth rectangular patch is connected to the left edge of the sixth rectangular patch, the right edge of the sixth rectangular patch is connected to the left edge of the seventh rectangular patch, the right edge of the seventh rectangular patch is connected to the left edge of the eighth rectangular patch, and the right edge of the eighth rectangular patch is connected to the left edge of the ninth rectangular patch. The top edges of the third rectangular patch, the fourth rectangular patch, the fifth rectangular patch, the seventh rectangular patch, the eighth rectangular patch, and the ninth rectangular patch are located on the same straight line, and the bottom edges of the fifth rectangular patch, the sixth rectangular patch, the seventh rectangular patch, and the ninth rectangular patch are located on the same straight line.

[0071] As Figure 9 shown, the length of the first rectangular patch is w 1 and the width is l 1 , the length of the second rectangular patch is l 2 and the width is w 3 , the side length of the first square patch is l 3 (or w 2 ), and the length of the third rectangular patch is l 4 and the width is w 4 .

[0072] The length of the fourth rectangular patch is (w 5 -w 4 -w 7 ) and the width is l 7 , the length of the fifth rectangular patch is l 5 and the width is w 7, the length of the sixth rectangular patch is (w 8 - w 7 ), the width is l 8 , the length of the seventh rectangular patch is l 5 and the width is w 7 , the length of the eighth rectangular patch is (w 6 - w 7 - w 10 ), the width is l 7 , the length of the ninth rectangular patch is l 5 and the width is w 10 .

[0073] As shown in (a) of Figure 6 , the length of the ground plane is w 11 and the width is l 9 , as shown in (b) of Figure 6 , the thickness of the dielectric substrate is h 1 , and the depth of the groove is h 2 .

[0074] The dimensions of the radiation patch, the ground plane and the dielectric substrate are shown in Table 2.

[0075] Table 2

[0076] Parameter Value Parameter Value <![CDATA[w 1 > 26mm <![CDATA[l 1 > 10mm <![CDATA[w 2 > 6mm <![CDATA[l 2 > 12mm <![CDATA[w 3 > 4mm <![CDATA[l 3 > 6mm <![CDATA[w 4 > 3mm <![CDATA[l 4 > 19mm <![CDATA[w 5 > 9mm <![CDATA[l 5 > 34mm <![CDATA[w 6 > 7.5mm <![CDATA[l 6 > 47mm <![CDATA[w 7 > 2mm <![CDATA[l 7 > 2mm <![CDATA[w 8 > 5mm <![CDATA[l 8 > 2mm <![CDATA[w 9 > 7mm <![CDATA[l 9 > 17.92mm <![CDATA[w 10 > 2mm <![CDATA[h 1 > 4.5mm <![CDATA[w 11 > 28.35mm <![CDATA[h 2 > 2.5mm

[0077] Example 6

[0078] A radio frequency antenna perfluorooctanoic acid sensor is substantially the same as the radio frequency antenna perfluorooctanoic acid sensor of Example 1, except that: the "boron-doped diamond radiation patch" is replaced with a "radiation patch (tantalum sheet)".

[0079] Example 7

[0080] A radio frequency antenna perfluorooctanoic acid sensor includes: a radiation patch loaded with a diamond film (the radiation patch loaded with a diamond film includes: a radiation patch and a diamond film loaded on the radiation patch), a dielectric substrate and a ground plane (copper foil). The radiation patch loaded with a diamond film, the dielectric substrate and the ground plane are arranged in parallel. The radiation patch loaded with a diamond film serves as a radiator. A groove for embedding the radiation patch loaded with a diamond film is formed on one side of the dielectric substrate. The shape of the groove is adapted to the radiation patch loaded with a diamond film. A ground plane is arranged on the other side of the dielectric substrate. An SMA head (radio frequency connector) connects the radiation patch loaded with a diamond film and the ground plane to form a radio frequency antenna perfluorooctanoic acid sensor. The method for preparing the radiation patch loaded with a diamond film is substantially the same as the "preparation method of the boron-doped diamond radiation patch" in Example 1, except that: no boron source is introduced.

[0081] Example 8

[0082] A radio frequency antenna perfluorooctanoic acid sensor is basically the same as that in Example 4, except that: for the preparation method of the boron-doped diamond radiation patch, this example does not include Step 1 in Example 4 and replaces the "radiation patch loaded with diamond nanoparticles" in Step 2 of Example 4 with "radiation patch".

[0083] Example 9

[0084] Perfluorooctanoic acid (solid) and methanol were mixed to prepare reagents with different concentrations of perfluorooctanoic acid (PFOA). The radio frequency antenna perfluorooctanoic acid sensor of Example 4 was used to perform static response tests on PFOA aerogel for each reagent with a concentration of perfluorooctanoic acid (PFOA), and S 11 curve was obtained. Among them, for the static response test of PFOA aerogel for each reagent with a concentration of perfluorooctanoic acid (PFOA): a reagent with a concentration of a certain perfluorooctanoic acid (PFOA) was atomized by an atomizer and introduced into standard air with a relative humidity of 30% to form a closed environment. The radio frequency antenna perfluorooctanoic acid sensor of Example 4 was placed in this closed environment for testing, and S 11 curve was obtained. By atomizing reagents with different concentrations of perfluorooctanoic acid (PFOA), the concentration of PFOA in the closed environment was made to be one of 0 ppt, 0.05 ppt, 0.1 ppt, 0.3 ppt, 0.5 ppt, 0.75 ppt, 1 ppt, 2.5 ppt, 5 ppt, 7.5 ppt, 10 ppt, 12.5 ppt, and 15 ppt. The S 11 curve obtained by placing the radio frequency antenna perfluorooctanoic acid sensor in closed environments with different concentrations of perfluorooctanoic acid (PFOA) is as Figure 7 shown. It can be seen from Figure 7 that the radio frequency antenna perfluorooctanoic acid sensor has a quantitative response to PFOA in the concentration range of 0.00 - 15 ppt.

[0085] For each concentration of perfluorooctanoic acid (PFOA) in the closed environment, the frequency value corresponding to the trough of the S 11 curve is f'. Then the frequency offset amount Δf of this concentration of perfluorooctanoic acid (PFOA) is Δf = f' - 2.45 (unit: GHz).

[0086] Taking the frequency offset amount Δf as the ordinate and the concentration of perfluorooctanoic acid (PFOA) in the closed environment as the abscissa, a coordinate system was established. The frequency offset amounts Δf of reagents with different concentrations of perfluorooctanoic acid (PFOA) and the concentration of perfluorooctanoic acid (PFOA) in the closed environment were substituted into the coordinate system and fitted to obtain a linear equation. As Figure 8As shown in the figure, within the PFOA concentration range of 0.00 to 1.78 ppt, the first linear equation is Δf (MHz) = -0.902C1 (ppt) -0.026, where C1 is the concentration of perfluorooctanoic acid (PFOA) in a closed environment, and R 2 =0.996; in the concentration range of 1.78 to 15.00 ppt, the second linear equation is Δf (MHz) = -0.337C2 (ppt) -1.067, C2 is the concentration of perfluorooctanoic acid (PFOA) in a closed environment, R 2 =0.981. The frequency offset of the intersection of the first linear equation and the second linear equation is -1.63156MHz. When the frequency offset of the environment to be tested is greater than -1.63156MHz, the first linear equation is applicable. When the frequency offset of the environment to be tested is less than -1.63156MHz, the second linear equation is applicable.

[0087] According to the signal-to-noise ratio method (Signal-to-Noise Ratio Method, refer to Song Q, Shan X, Jiang D, et al. 2DZn-based metal-organic framework as an efficientelectrochemiluminescence emitter: A novel inner filter effect-based ECLbiosensor for trace detection of bisphenol A[J].Analytica Chimica Acta, 2025, 1335. DOI: 10.1016 / j.aca.2024.343416.), the detection limit (LOD) of the radio frequency antenna perfluorooctanoic acid sensor of Example 4 for PFOA is 0.0136 ppt, which is much lower than the detection limit of existing antenna sensors for PFOA (the detection limit of existing antenna sensors for PFOA is about 1 to 5 ppt).

[0088] The radio frequency antenna perfluorooctanoic acid sensor of Example 4 was connected to a power source, a portable spectrum analyzer was used as a receiving device, seawater (seawater containing PFOA) of known concentration was atomized by an atomizer and introduced into standard air with a relative humidity of 30% to form a closed environment, so that the concentration of PFOA after atomization in the closed environment was 5 ppt, and the radio frequency antenna perfluorooctanoic acid sensor of Example 4 was placed in the closed environment for testing to obtain a radio frequency antenna perfluorooctanoic acid sensor S 11The frequency value corresponding to the trough of the curve is 2447.2 MHz, that is, the frequency offset is -2.8 MHz. Since -2.8 MHz is less than -1.63156 MHz, substituting it into the second linear equation gives a PFOA concentration value of 5.14 ppt, which is close to the concentration of PFOA after atomization in a closed environment, fully demonstrating the precise ability of the radio frequency antenna perfluorooctanoic acid sensor to detect PFOA substances.

[0089] Figure 1 Appearance of the boron-doped diamond radiation patch of Example 4.

[0090] Characterize the boron-doped diamond radiation patches obtained in Examples 1 to 5 and the radiation patches loaded with diamond films in Example 7. Figure 2 Surface SEM images of the boron-doped diamond radiation patches prepared in Examples 1 to 5 and the radiation patches loaded with diamond films in Example 7. Figure 3 Cross-sectional SEM images of the boron-doped diamond radiation patches prepared in Examples 1 to 5 and the radiation patches loaded with diamond films in Example 7. From Figure 2 and Figure 3 It can be seen that the surface of the boron-doped diamond radiation patch is covered with a boron-doped diamond film (polycrystalline BDD film), most of the surface crystals are exposed on the (111) plane, and the crystals grow in a columnar shape and are closely packed. The flow rate of H 2 (carrier gas) has little effect on the particle size of the boron-doped diamond (BDD) crystals. When the carrier gas flow rate increases in the range of 12 - 36 mL min -1 the grain size of the boron-doped diamond crystals is not significantly affected, and the average particle size is between 0.77 and 0.97 μm. The thickness of the boron-doped diamond film fluctuates in the range of 1.80 - 4.1 μm.

[0091] Figure 4 Schematic diagram of the assembly process of the radio frequency antenna perfluorooctanoic acid sensor of Example 1 ( Figure 4 in which "boron-doped diamond radiation sheet" represents the boron-doped diamond radiation patch, "tantalum" represents the radiation patch, "copper" represents the ground plane, and "antenna" represents the radio frequency antenna perfluorooctanoic acid sensor). Figure 5 Physical photo of the radio frequency antenna perfluorooctanoic acid sensor of Example 1.

[0092] Use one of the radio frequency antenna perfluorooctanoic acid sensors in Examples 1 to 7 to conduct tests according to the aforementioned "Static Response Test of PFOA Aerogel". Among them, the concentrations of PFOA in the closed environment are 0 ppt, 1.25 ppt, 2.5 ppt, 5 ppt, 7.5 ppt, and 10 ppt, and 6 S 11 curves are obtained. Calculate each S 11The frequency offset Δf corresponding to the curve, taking the frequency offset Δf as the ordinate and the concentration of perfluorooctanoic acid (PFOA) in the closed environment as the abscissa, establish a coordinate system, and for the 6 S 11 curves, substitute the corresponding frequency offset Δf and the concentration of perfluorooctanoic acid (PFOA) in the closed environment into the coordinate system and perform fitting to obtain a linear equation, as Figure 10 shown ( Figure 10 in which "Ta / PDMS" represents Example 6, "Dia.-Ta / PDMS" represents Example 7, "BDD 12 -Ta / PDMS" represents Example 1, "BDD 18 -Ta / PDMS" represents Example 2, "BDD 24 -Ta / PDMS" represents Example 3, "BDD 30 -Ta / PDMS" represents Example 4, "BDD 36 -Ta / PDMS" represents Example 5), and then obtain the sensitivity of the radio frequency antenna perfluorooctanoic acid sensor, as Figure 11 shown. From Figure 10 and Figure 11 , it can be seen that the sensitivity of the radio frequency antenna perfluorooctanoic acid sensor in Example 6 is 0.207 MHz / ppt -1 , and the sensitivity of the radio frequency antenna perfluorooctanoic acid sensor in Example 4 is the highest, reaching 0.409 MHz / ppt -1 . PDMS has hydrophobicity, and hydrophobic PFOA aerosol particles are easily adsorbed on the surface of the boron-doped diamond radiation patch. In addition, due to the hydrophobicity and lipophilicity of the sp 3 -C hybrid non-polar bonds in diamond, by covering the tantalum (Ta) sheet with a pure diamond film (without introducing a B source), the sensitivity of the radio frequency antenna perfluorooctanoic acid sensor in Example 7 is improved. Further, after introducing a B source into the diamond layer, the sensitivity to PFOA is significantly increased. The radio frequency antenna perfluorooctanoic acid sensor in Example 4 exhibits the highest PFOA sensitivity (B source carrier gas flow rate is 30 mL / min -1 ), and the sensitivity value reaches 1.98 times that of the radio frequency antenna perfluorooctanoic acid sensor in Example 6.

[0093] Anti-interference test

[0094] "1 ppt - interference" group: Atomize the perfluorooctanoic acid (PFOA) ethanol solution and introduce it into the closed environment so that the concentration of PFOA in the closed environment is 1 ppt. At the same time, introduce interfering substances into the closed environment, and place the radio frequency antenna perfluorooctanoic acid sensor of Example 4 into the closed environment for testing to obtain the S 11 curve;

[0095] "0ppt - interference" group: Only introduce the interfering substance (without introducing PFOA) into the closed environment, and place the perfluorooctanoic acid sensor of the radio frequency antenna in Example 4 into the closed environment for testing to obtain the S 11 curve;

[0096] In the "1ppt - interference" group and the "0ppt - interference" group, the interfering substances are water vapor at 90% RH, urea (Urea) vapor at 100 μM, NH 3 at 200000 ppm, dry CO 2 at 1000 ppm, dry N 2 at 800000 ppm, and perfluorooctyltrichlorosilane (PFOTS) at 1 ppt, respectively.

[0097] "1ppt" group: It is basically the same as the "1ppt - interference" group, and the only difference is that no interfering substance is introduced.

[0098] "0ppt" group: It is basically the same as the "0ppt - interference" group, and the only difference is that no interfering substance is introduced.

[0099] The S 11 curves obtained from the "1ppt - interference" group, "0ppt - interference" group, "1ppt" group, and "0ppt" group are as Figure 12 shown, where Figure 12 a is for the "1ppt" group and the "0ppt" group, Figure 12 b is for the "1ppt - interference" group and the "0ppt - interference" group (with the interfering substance being 1 ppt of perfluorooctyltrichlorosilane), Figure 12 c is for the "1ppt - interference" group and the "0ppt - interference" group (with the interfering substance being water vapor at 90% RH), Figure 12 d is for the "1ppt - interference" group and the "0ppt - interference" group (with the interfering substance being 100 μM of urea (Urea) vapor), Figure 12 e is for the "1ppt - interference" group and the "0ppt - interference" group (with the interfering substance being 200000 ppm of NH 3 ), Figure 12 f is for the "1ppt - interference" group and the "0ppt - interference" group (with the interfering substance being 1000 ppm of dry CO 2 ), Figure 12 g is for the "1ppt - interference" group and the "0ppt - interference" group (with the interfering substance being 800000 ppm of dry N 2 ).

[0100] As Figure 12 shown, in Figure 12 a, the frequency value of the "1ppt" group is 2441.15 MHz, inFigure 12 In b of Figure 12 In c of Figure 12 In d of Figure 12 In e of Figure 12 In f of Figure 12 In g of

[0101] When the radio frequency antenna perfluorooctanoic acid sensor of Example 8 is used for the concentration detection of perfluorooctanoic acid (PFOA), its sensitivity is lower than that of the radio frequency antenna perfluorooctanoic acid sensor of Example 4, and the detection limit is also not as low as that of Example 4. The reasons are as follows: 1. The loading of diamond nanoparticles can significantly improve the surface activity of the diamond film, making it show higher reactivity in chemical reactions. 2. Diamond nanoparticles have extremely high hardness. After being loaded on the surface of the diamond film, they can enhance the wear resistance and scratch resistance of the film, improving the overall mechanical properties of the material. 3. Diamond nanoparticles can regulate the conductivity of the diamond film, helping to improve the electrical properties of the material, especially improving the charge transfer efficiency. 4. Diamond nanoparticles can increase the adsorption capacity of the diamond film for perfluorooctanoic acid (PFOA), thereby improving the sensitivity of the radio frequency antenna perfluorooctanoic acid sensor detection.

[0102] The present invention uses polydimethylsiloxane (PDMS) and boron-doped diamond (BDD) as the sensitive film materials of the radio frequency antenna perfluorooctanoic acid sensor. The combination of the two provides excellent chemical and physical properties, providing a basis for the efficient sensing of PFOA. PDMS can adsorb oily molecules and at the same time has good hydrophobicity, making the radio frequency antenna perfluorooctanoic acid sensor show stability in the high-humidity marine environment and suitable for detecting hydrophobic pollutants such as PFOA. And boron-doped diamond has high chemical stability and unique hydrogen bond forces, and can effectively capture fluorine-containing pollutant molecules.

[0103] The above makes an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification or equivalent substitution that can be made by those skilled in the art without creative labor falls within the protection scope of the present invention.

Claims

1. A boron-doped diamond radiation patch, characterized in that: include: A radiation patch and a boron-doped diamond film loaded on the radiation patch, wherein the thickness of the boron-doped diamond film is 1.5-4.5 μm.

2. A method for preparing a boron-doped diamond radiation patch, characterized in that: include: A boron-doped diamond film is prepared on a radiation patch to obtain a boron-doped diamond radiation patch.

3. The preparation method according to claim 2, characterized in that: The method for preparing a boron-doped diamond radiation patch comprises the following steps: Step 1, immersing the radiation patch in a diamond nanoparticle dispersion, ultrasonicating, cleaning, and drying to obtain a radiation patch loaded with diamond nanoparticles; Step 2, placing the radiation patch loaded with diamond nanoparticles on the sample stage of the vacuum deposition chamber in the CVD system, sealing the vacuum deposition chamber, evacuating the vacuum deposition chamber, introducing hydrogen and methane into the vacuum deposition chamber, and applying 110-120A of alternating current to the AC filament in the vacuum deposition chamber when the pressure in the vacuum deposition chamber reaches 11-12 Torr, and when the pressure in the vacuum deposition chamber reaches 37.5-38.5 Torr, continue to apply 110-120A of alternating current to the AC filament in the vacuum deposition chamber at this pressure for 30-35 minutes; Step 3, continue to introduce hydrogen and methane into the vacuum deposition chamber, maintain the pressure in the vacuum deposition chamber at 37.5-38.5 Torr, introduce a boron source into the vacuum deposition chamber, apply a DC bias between the sample stage and the AC filament, and apply AC to the AC filament, so that the DC bias and the AC together make the temperature of the environment where the radiation patch reaches 850-900°C, and maintain this condition for 1.5-2 hours until a boron-doped diamond film is grown on the radiation patch to obtain a boron-doped diamond radiation patch.

4. The preparation method according to claim 3, characterized in that: In step 3, the boron source is a mixture of trimethyl borate and ethanol, and the boron source is atomized and introduced into the vacuum deposition chamber through a carrier gas, and the flow rate of the carrier gas is 12 to 36 mL min -1 .

5. The preparation method according to claim 3, characterized in that: In step 1, the diamond nanoparticle dispersion is a mixture of diamond nanoparticles and anhydrous ethanol, and the concentration of diamond nanoparticles in the diamond nanoparticle dispersion is 2 to 3 mg mL -1 .

6. A radio frequency antenna perfluorooctanoic acid sensor, characterized in that: include: A boron-doped diamond radiation patch, a dielectric substrate and a grounding plate, wherein the boron-doped diamond radiation patch, the dielectric substrate and the grounding plate are arranged in parallel, the boron-doped diamond radiation patch serves as a radiator, a groove for embedding the boron-doped diamond radiation patch is formed on one surface of the dielectric substrate, and the shape of the groove is suitable for the boron-doped diamond radiation patch, and the grounding plate is arranged on the other surface of the dielectric substrate, and the boron-doped diamond radiation patch is one of the boron-doped diamond radiation patch according to claim 1 and the boron-doped diamond radiation patch obtained by the preparation method according to claims 2 to 4; The radiation patch includes: a T-shaped patch, a fourth rectangular patch, a fifth rectangular patch, a sixth rectangular patch, a seventh rectangular patch, an eighth rectangular patch and a ninth rectangular patch, wherein: The T-shaped patch includes: a first rectangular patch, a second rectangular patch, a first square patch and a third rectangular patch, the length direction of the first rectangular patch is horizontally arranged, the length directions of the second rectangular patch and the third rectangular patch are vertically arranged, the bottom edge of the first square patch is arranged in the horizontal direction, the bottom edge of the second rectangular patch is connected to the center position of the top edge of the first rectangular patch, the top edge of the second rectangular patch is connected to the bottom edge of the first square patch, and the top edge of the first square patch is connected to the bottom edge of the third rectangular patch; The length direction of the fourth rectangular patch is set horizontally, and the right edge of the third rectangular patch is connected to the left edge of the fourth rectangular patch; the length directions of the fifth rectangular patch, the seventh rectangular patch and the ninth rectangular patch are set vertically, and the length directions of the sixth rectangular patch and the eighth rectangular patch are set horizontally, and the right edge of the fourth rectangular patch is connected to the left edge of the fifth rectangular patch, the right edge of the fifth rectangular patch is connected to the left edge of the sixth rectangular patch, the right edge of the sixth rectangular patch is connected to the left edge of the seventh rectangular patch, the right edge of the seventh rectangular patch is connected to the left edge of the eighth rectangular patch, and the right edge of the eighth rectangular patch is connected to the left edge of the ninth rectangular patch. The top edges of the third rectangular patch, the fourth rectangular patch, the fifth rectangular patch, the seventh rectangular patch, the eighth rectangular patch and the ninth rectangular patch are located in the same straight line, and the bottom edges of the fifth rectangular patch, the sixth rectangular patch, the seventh rectangular patch and the ninth rectangular patch are located in the same straight line.

7. Use of the radio frequency antenna perfluorooctanoic acid sensor as claimed in claim 6 in detecting perfluorooctanoic acid.

8. The use according to claim 7, characterized in that The method of detecting perfluorooctanoic acid by the radio frequency antenna perfluorooctanoic acid sensor includes: S1, obtained by testing the S of the RF antenna PFOA sensor at different PFOA concentrations 11 Curve; According to each S 11 The curve obtains a frequency offset Δf; S2, using the frequency shift Δf as the ordinate and the concentration of perfluorooctanoic acid as the abscissa, establishing a coordinate system, substituting the frequency shift Δf obtained with different perfluorooctanoic acid concentrations in S1 and the concentration of perfluorooctanoic acid into the coordinate system and fitting, obtaining at least one straight line, and obtaining a linear equation for each straight line; S3, obtain the S of the RF antenna perfluorooctanoic acid sensor in the test environment 11 The frequency offset Δf of the environment to be tested is obtained by using a curve, and the frequency offset Δf of the environment to be tested is substituted into the linear equation of S2 to calculate the concentration of perfluorooctanoic acid in the environment to be tested.

9. The use according to claim 8, characterized in that Each S 11 The frequency value corresponding to the trough of the curve is f', and the frequency offset Δf=f'-2.45, in units of GHz.

10. The use according to claim 8, characterized in that The environment to be tested is a gas phase, a liquid phase, or a gas-liquid mixed phase.

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