Vortex flexible fiber membrane with interstitial ammonia gas measurement function and development method of vortex flexible fiber membrane

Abstract

The invention discloses a vortex flexible fiber membrane with an interstitial ammonia gas measurement function and a development method of the vortex flexible fiber membrane. The vortex flexible fiber membrane is composed of a flexible thermoplastic polyurethane (TPU) fiber membrane, a copper electrode lead and a vortex sensitive layer; the preparation method comprises the following steps: preparing a flexible TPU fiber film by adopting a high-voltage electrostatic spinning process; preparing a copper electrode lead on the surface of the flexible TPU fiber film through a magnetron sputtering process, and then preparing through holes in the two ends of the copper electrode lead; preparing a carboxylated multi-walled carbon nanotube and dodecylbenzene sulfonic acid doped polyaniline composite dispersion liquid, covering the surface, away from the copper electrode lead, of the flexible TPU fiber film with a spiral mask, and depositing the composite dispersion liquid on the surface of the flexible TPU fiber film through a pneumatic spraying technology to form a vortex sensitive layer; a multi-process fusion technology is adopted, and the prepared vortex flexible fiber membrane with the gap ammonia gas measurement function can be directly attached to a curved surface and has the capability of detecting the gap and the ammonia gas concentration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible sensing, in particular to a vortex flexible fiber membrane with gap ammonia measurement function and a preparation method thereof. BACKGROUND

[0002] Under the impetus of the development of intelligent equipment, precision equipment is evolving towards high integration, which significantly reduces the internal space and makes it difficult to deploy multiple independent single-function sensors to achieve multi-state monitoring. In this context, the exploration and application of multifunctional sensors have gradually become an important technical path to realize predictive health management (PHM) of equipment. Ammonia (NH3) is widely used in industry and has a pungent odor and corrosive properties. Its concentration monitoring is directly related to personnel safety and stable operation of equipment. Ammonia accumulation in a closed space can corrode metal components, accelerate equipment aging, and even cause system failure. Therefore, rapid and accurate detection of ammonia is crucial to ensure the safety of the environment and personnel health of high-end equipment. Distance monitoring is indispensable in the operation of high-end precision equipment, especially the change of the curved gap between spherical bearings and special-shaped parts, which is the focus of attention in the field of precision engineering. Its change directly changes the friction and stress distribution of the parts, and then affects the stability of the power output and the overall efficiency of the equipment. The integrated detection of ammonia and distance has important research significance and engineering value for comprehensively sensing the state of the equipment, improving system reliability, and breaking through the installation space limit. However, traditional ammonia and distance sensors are single-function and non-flexible devices, which are difficult to integrate and install in narrow curved environments. Therefore, it is urgent to develop a flexible sensing element suitable for narrow curved environments to realize the synchronous monitoring of ammonia concentration and distance change. SUMMARY

[0003] (I) Technical problem

[0004] The present application provides a vortex flexible fiber membrane with gap ammonia measurement function and a preparation method thereof. The vortex flexible fiber membrane is prepared by combining high-voltage electrospinning, magnetron sputtering, pneumatic spraying technology and mask method, and has both ammonia concentration and gap sensing capabilities.

[0005] (II) Technical solution

[0006] The vortex flexible fiber membrane with gap ammonia measurement function provided by the present application comprises: a flexible thermoplastic polyurethane (TPU) fiber film; a copper electrode lead arranged on one surface of the flexible TPU fiber film; and a vortex sensitive layer arranged on the other surface of the flexible TPU fiber film.

[0007] The flexible TPU fiber film is prepared by electrospinning process, and the average diameter of the fiber is about 1.5 pm.

[0008] The copper electrode lead is prepared by a magnetron sputtering technique, and includes circular end portions at two ends and a middle connecting line connecting the two circular end portions, and the circular end portions are provided with through holes;

[0009] The vortex sensitive layer comprises a composite material of carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and dodecyl benzene sulfonic acid doped polyaniline (DBSA-PANI), and has a pattern of multiple spiral lines with preset line width and spacing, which can stimulate the electric eddy current effect; and one end of the vortex sensitive layer is electrically connected with a circular end portion of the copper electrode lead.

[0010] A preparation method of a vortex flexible fiber membrane with a gap ammonia gas measurement function, comprising the following steps:

[0011] (1) Preparing a flexible TPU fiber film: preparing a TPU solution with a mass fraction of 59% by using N,N-dimethylformamide (DMF) as a solvent, and performing high-voltage electrospinning under the conditions of an ambient temperature of 35°C, a relative humidity of 30% RH, a positive voltage of 16.2 kV, a negative voltage of 1.53 kV, a spinning distance of 24 cm, a solution advancing rate of 0.5 mL / h, and a receiving roller rotating speed of 150 r / min for 10 hours to prepare a flexible TPU fiber film with an average fiber diameter of about 1.5 μm;

[0012] (2) Preparing a copper electrode lead: sequentially ultrasonically cleaning the flexible TPU fiber film with ethanol and deionized water, drying, and then cutting the flexible TPU fiber film into a rectangle with a length of 50 mm and a width of 40 mm; covering an electrode mask with a length of 50 mm, a width of 40 mm, and a thickness of 0.1 mm on the surface of the flexible TPU fiber film, and depositing a copper layer by using a magnetron sputtering process, wherein a base vacuum degree is 3×10 -4 Pa, an argon gas flow rate is 42 sccm, a sputtering power is 150 W, a sample table rotating speed is 3 r / min, and a sputtering time is 600 s; and removing the electrode mask to obtain the copper electrode lead;

[0013] (3) Preparing a through hole: performing a perforation operation on the center positions of the two circular end portions of the copper electrode lead by using a needle tip wetted with DMF to form a through hole with a hole diameter of 0.5 mm;

[0014] (4) Preparing a MWCNT-COOH and DBSA-PANI composite dispersion liquid: adding 0.040 g of sodium dodecyl benzene sulfonate (SDBS) into 40 mL of deionized water, magnetically stirring and dissolving, then adding 0.040 g of MWCNT-COOH, ultrasonically treating for 2 hours, and continuously stirring for 12 hours; subsequently adding 0.100 g of DBSA-PANI, continuously stirring for 30 minutes, and obtaining the MWCNT-COOH and DBSA-PANI composite dispersion liquid;

[0015] (5) Forming the vortex-sensitive layer: A spiral mask with a length of 50 mm, a width of 40 mm, a thickness of 0.1 mm, and a line width and line spacing of 0.5 mm, consisting of 10 turns, is placed on the surface of the flexible TPU fiber film away from the copper electrode leads. A magnet is placed at the bottom of the flexible TPU fiber film to ensure that the spiral mask and the flexible TPU fiber film are in close contact without gaps. Then, it is placed on a constant temperature heating table. The high-pressure gas from the air compressor is connected to the spray gun. Using a pneumatic spraying process with a spray gun nozzle diameter of 0.2 mm, a spraying air pressure of 0.5 MPa, and a spraying distance of 15 cm, the composite dispersion of MWCNT-COOH and DBSA-PANI is atomized and sprayed onto the window area of ​​the spiral mask. After the solvent evaporates, the spraying is repeated until the required thickness is reached. Finally, the vortex-sensitive layer is formed by heating and drying.

[0016] The vortex-based sensing layer, based on the synergistic effect of MWCNT-COOH and DBSA-PANI composite materials, enables dual-parameter detection of ammonia concentration and gap. Under DC excitation, the sensing layer functions as a resistive sensing unit: DBSA-PANI is rich in N... + The p-type semiconductor with -H adsorption sites, when exposed to ammonia gas, is exposed to ammonia gas which extracts protons (H+) from the DBSA-PANI molecular chain. + ) generates NH4 + Simultaneously, electrons transfer to the DBSA-PANI molecular chain; the π-π conjugated structure between MWCNT-COOH and DBSA-PANI enhances electron delocalization, driving further charge transfer to MWCNT-COOH, reducing the hole concentration in DBSA-PANI, and consequently increasing the resistance of the sensing element; after ammonia desorption, the deprotonation process reverses the charge transfer, and the resistance of the sensing element gradually returns to its initial state. Based on the direct correlation between the resistance change and the ammonia concentration, quantitative detection of ammonia can be achieved. Furthermore, this helical structure is equivalent to a planar coil under AC excitation. This structure can excite eddy current effects, and its impedance is affected by induced eddy currents in nearby metals or conductors. By detecting changes in AC impedance, gap detection can be achieved.

[0017] (III) Beneficial Effects

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] 1. This invention achieves the integrated fabrication of a flexible substrate, conductive electrodes, and sensitive layers by combining masking with three processes: high-voltage electrospinning, magnetron sputtering, and pneumatic spraying. Each functional layer is tightly bonded to the substrate, ensuring the stability of the sensing element under complex conditions such as bending and attachment.

[0020] 2. Thanks to the TPU fiber film substrate prepared by high-voltage electrospinning, this sensing element is both thin and flexible, and can be closely attached to narrow and irregular curved surfaces such as pipes and bends. At the same time, based on the vortex-shaped sensitive layer structure, it can simultaneously monitor two parameters: ammonia concentration (based on DC resistance change) and gap (based on AC impedance change), effectively solving the problems of traditional rigid sensors being difficult to attach to curved surfaces and having limited functions. Attached Figure Description

[0021] Figure 1 This is a process flow diagram for the preparation of a vortex-type flexible fiber membrane that also has the function of measuring interstitial ammonia.

[0022] Figure 2 This is a schematic diagram of the structure of a flexible TPU fiber film;

[0023] Figure 3 This is a schematic diagram of the electrode mask structure;

[0024] Figure 4 This is a schematic diagram of the spiral mask structure;

[0025] Figure 5 These are top and cross-sectional views of a vortex-type flexible fiber membrane that also has the function of measuring interstitial ammonia.

[0026] Figure 6 This is a scanning electron microscope image of the flexible TPU fiber film prepared by high voltage electrospinning in Example 1;

[0027] Figure 7 This is a scanning electron microscope image of the vortex-sensitive layer sprayed on the surface of the flexible TPU fiber film in Example 1;

[0028] Figures 1 to 5 In the diagram, a represents flexible TPU fiber film; b represents electrode mask; c represents copper target; d represents copper electrode lead; e represents through hole; f represents spiral mask; g represents spray gun; and h represents vortex sensitive layer. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be noted that the present invention can be implemented in many different forms, and the described embodiments are only intended to facilitate the understanding of the present invention and do not constitute any limitation thereof.

[0030] See Figure 1 As shown, a method for preparing a vortex-type flexible fiber membrane with intermittent ammonia measurement function includes the following steps:

[0031] (1) Preparation of flexible TPU fiber film a: A TPU solution with a mass fraction of 59% was prepared using N,N-dimethylformamide (DMF) as solvent. High-voltage electrospinning was carried out for 10 hours under the conditions of ambient temperature of 35℃, relative humidity of 30%RH, positive voltage of 16.2kV, negative voltage of 1.53kV, spinning distance of 24cm, solution feed rate of 0.5mL / h, and receiving roller speed of 150r / min to obtain a flexible TPU fiber film a with an average fiber diameter of about 1.5μm.

[0032] (2) Preparation of copper electrode leads d: The flexible TPU fiber film a is ultrasonically cleaned with ethanol and deionized water in sequence, dried, and then cut into a rectangle with a length of 50 mm and a width of 40 mm. Its structural schematic diagram is shown below. Figure 2 As shown; then will Figure 3 The electrode mask b (50 mm long, 40 mm wide, and 0.1 mm thick) of the structure shown is covered on the surface of the flexible TPU fiber film a. Then, a copper target c is deposited onto the film surface using magnetron sputtering. The process parameters are as follows: base vacuum 3 × 10⁻⁶. -4 Pa, argon flow rate 42 sccm, sputtering power 150 W, sample stage rotation speed 3 r / min, sputtering time 600 s; after removing electrode mask b, copper electrode lead d is obtained;

[0033] (3) Preparation of through hole e: Use a needle tip wetted with DMF to pierce the center of the circular ends of the copper electrode lead d to form a through hole e with a diameter of 0.5 mm;

[0034] (4) Preparation of MWCNT-COOH and DBSA-PANI composite dispersion: Add 0.040g sodium dodecylbenzenesulfonate (SDBS) to 40mL of deionized water, stir magnetically to dissolve, then add 0.040g MWCNT-COOH, sonicate for 2 hours, and then continue stirring for 12 hours; then add 0.100g DBSA-PANI, and continue stirring for 30 minutes to obtain MWCNT-COOH and DBSA-PANI composite dispersion;

[0035] (5) Forming the vortex-sensitive layer h: Take a spiral-shaped mask f, the structural diagram of which is shown below. Figure 4As shown, the specific dimensions are 50mm in length, 40mm in width, and 0.1mm in thickness, with a line width and spacing of 0.5mm, and a total of 10 turns. This is applied to the surface of the flexible TPU fiber film a facing away from the copper electrode lead d. A magnet is then placed at the bottom of the flexible TPU fiber film, and the entire assembly is placed on a constant-temperature heating platform. High-pressure gas from an air compressor is connected to a spray gun g. Using a pneumatic spraying process with a nozzle diameter of 0.2mm, a spraying pressure of 0.5MPa, and a spraying distance of 15cm, the MWCNT-COOH and DBSA-PANI composite dispersion is atomized and sprayed onto the window area of ​​the spiral mask f. After the solvent evaporates, the spraying is repeated until the desired thickness is achieved. Finally, after heating and drying, a vortex-sensitive layer h is formed, thus producing a vortex-sensitive flexible fiber membrane with both gap and ammonia measurement functions. Its structure is as follows. Figure 5 As shown, it includes: a flexible TPU fiber film a, a copper electrode lead d disposed on one surface of the flexible TPU fiber film a; a through hole e located at the circular end of the copper electrode lead d; and a vortex-sensitive layer h disposed on the other surface of the flexible TPU fiber film a.

[0036] Example 1

[0037] See Figure 1 As shown, a method for preparing a vortex-type flexible fiber membrane with intermittent ammonia measurement function includes the following steps:

[0038] (1) Preparation of flexible TPU fiber film: A quantitative amount of TPU particles was slowly added to DMF solvent in batches to prepare a TPU solution with a mass fraction of 59%; the mixture was placed on a magnetic stirrer, the stirring speed was set to 200 r / min, and stirring was continued for 12 hours until the TPU particles were completely dissolved, forming a homogeneous, transparent solution without obvious particles; then the solution was allowed to stand at room temperature for 60 minutes to remove bubbles generated by stirring, so as to avoid defects such as fiber breakage and droplets in the subsequent spinning process; then the TPU solution after standing and degassing was loaded into... A 20mL syringe (equipped with a No. 20 stainless steel needle) was used for spinning using a high-voltage electrospinning device. The spinning process parameters were set as follows: ambient temperature 35℃, relative humidity 30%RH, positive voltage 16.2kV, negative voltage 1.53kV, spinning distance 24cm, solution feed rate 0.5mL / h, receiving roller speed 150r / min, and spinning time 10 hours. After spinning, the TPU fiber film on the receiving roller was removed and dried in a 50℃ forced-air drying oven for 2 hours, finally obtaining a flexible TPU fiber film with an average fiber diameter of approximately 1.5μm.

[0039] (2) Fabrication of copper electrode leads: The flexible TPU fiber film was cut into rectangles with dimensions of 50mm × 40mm, as shown in the schematic diagram below. Figure 2As shown, the sample was then placed sequentially in anhydrous ethanol and deionized water, and ultrasonically cleaned for 15 minutes each (ultrasonic power 100W, frequency 60kHz) to remove surface oil and impurities; after cleaning, it was placed in a forced-air drying oven and dried at 60℃ for 2 hours; then... Figure 3 An electrode mask (stainless steel, 50 mm long, 40 mm wide, and 0.1 mm thick) is placed over the surface of a flexible TPU fiber film. A magnet is then placed at the bottom of the flexible TPU fiber film to ensure a gapless fit between the electrode mask and the film. Next, a magnetron sputtering process is used to deposit a 99.99% high-purity copper target mounted at a DC target position onto the surface of the flexible TPU fiber film. The sputtering parameters are: a base vacuum of 3 × 10⁻⁶. -4 Pa, argon flow rate 42 sccm, sputtering power 150 W, sample stage speed 3 r / min, sputtering time 600 s; after sputtering, the electrode mask is removed to obtain the copper electrode leads.

[0040] (3) Preparation of through holes: Select a stainless steel needle (outer diameter 0.5 mm, inner diameter 0.3 mm), use a pipette to draw DMF solution and drop it onto the needle tip to fully wet the needle tip with DMF; lay the flexible TPU fiber film with copper electrode leads flat on the acrylic plate, fix the position, and use the DMF-wetted needle tip to align with the center of the circular ends of the copper electrode leads, apply uniform pressure vertically downward to pierce the hole, and finally form a through hole with a diameter of 0.5 mm.

[0041] (4) Preparation of MWCNT-COOH and DBSA-PANI composite dispersion: Add 0.040g sodium dodecylbenzenesulfonate (SDBS) to 40mL of deionized water, place on a magnetic stirrer (600r / min) and stir at room temperature for 30 minutes to completely dissolve SDBS and form a clear surfactant aqueous solution; add 0.040g MWCNT-COOH (purity >98%, outer diameter 30-50nm, length <10μm) to the above SDBS aqueous solution, first sonicate in an ultrasonic cleaner (power 100W, frequency 60kHz) for 2 hours, then magnetically stir at 800r / min for 12 hours to uniformly disperse MWCNT-COOH; then continue to add 0.100g to the dispersion. DBSA-PANI (molecular weight: 5W-6W) was magnetically stirred (800 r / min) for 30 minutes to fully mix the DBSA-PANI and MWCNT-COOH dispersions, ultimately obtaining a uniform and stable composite dispersion of MWCNT-COOH and DBSA-PANI.

[0042] (5) Forming the vortex-sensitive layer: A spiral-shaped mask (made of stainless steel) is used, and its structural diagram is shown below. Figure 4As shown, the specific dimensions are 50mm long, 40mm wide, and 0.1mm thick, with a line width and spacing of 0.5mm, totaling 10 turns. This is applied to the surface of the flexible TPU fiber film facing away from the copper electrode leads. A magnet is then placed at the bottom of the flexible TPU fiber film to ensure a seamless fit between the spiral mask and the flexible TPU fiber film. It is then preheated on a constant-temperature heating table (80℃) for 5 minutes. High-pressure gas from an air compressor is connected to the spray gun (nozzle diameter 0.2mm), and the spraying pressure is adjusted to 0.5MPa. The prepared MWC... The NT-COOH and DBSA-PANI composite dispersion was loaded into the spray gun cup, and the vertical distance between the spray gun and the spiral mask was adjusted to 15 cm. The spray gun was then turned on for atomized spraying, with each spray lasting 5 seconds, followed by a 10-second pause, repeated 30 times. After spraying, the dispersion was transferred to a forced-air drying oven and heated to 60°C for 12 hours to ensure complete solvent removal. After cooling to room temperature, the spiral mask was removed, thus forming a vortex-sensitive layer on the surface of the flexible TPU fiber film, completing the preparation of the vortex-type flexible fiber membrane with interstitial ammonia measurement function. (See also...) Figure 5 As shown, the prepared vortex-type flexible fiber membrane with intermittent ammonia measurement function includes: a flexible TPU fiber film; a copper electrode lead disposed on one surface of the flexible TPU fiber film; a through hole located at the circular end of the copper electrode lead to realize the electrical connection between the copper electrode lead and the vortex-type sensitive layer; and a vortex-type sensitive layer disposed on the other surface of the flexible TPU fiber film.

[0043] like Figure 6 As shown, the flexible TPU fiber film exhibits a typical fibrous microstructure, with fibers interwoven to form a three-dimensional network structure with a certain porosity, and the average fiber diameter is about 1.5 μm.

[0044] Depend on Figure 7 The scanning electron microscope image of the vortex-sensitive layer sprayed on the surface of the flexible TPU fiber film shows that the MWCNT-COOH and DBSA-PANI composite material is uniformly adsorbed and tightly bonded to the TPU fiber surface. A good interfacial bond is formed between the composite material and the TPU fiber, and the overall sensitive layer structure exhibits interconnected porous features, which provides a solid microstructure support for the realization of its ammonia sensing performance.

[0045] The sensing process of the aforementioned vortex-type flexible fiber membrane with gap ammonia measurement function is as follows: The vortex-type sensitive layer, based on the synergistic effect of the MWCNT-COOH and DBSA-PANI composite materials, can achieve dual-parameter detection of ammonia concentration and gap. Under DC excitation, the sensitive layer operates as a resistive sensing unit: DBSA-PANI is rich in N... +The p-type semiconductor with -H adsorption sites, when exposed to ammonia gas, is exposed to ammonia gas which extracts protons (H+) from the DBSA-PANI molecular chain. + ) generates NH4 + Simultaneously, electrons transfer to the DBSA-PANI molecular chain; the π-π conjugated structure between MWCNT-COOH and DBSA-PANI enhances electron delocalization, driving further charge transfer to MWCNT-COOH, reducing the hole concentration in DBSA-PANI, and consequently increasing the resistance of the sensing element; after ammonia desorption, the deprotonation process reverses the charge transfer, and the resistance of the sensing element gradually returns to its initial state. Based on the direct correlation between the resistance change and the ammonia concentration, quantitative detection of ammonia can be achieved. Furthermore, this helical structure is equivalent to a planar coil under AC excitation. This structure can excite eddy current effects, and its impedance is affected by induced eddy currents in nearby metals or conductors. By detecting changes in AC impedance, gap detection can be achieved.

[0046] Finally, the implementation method of the present invention is merely a preferred embodiment and does not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vortexed flexible fiber membrane having a gap ammonia measurement function, characterized by, It comprises: a flexible thermoplastic polyurethane (TPU) fiber film; a copper electrode lead arranged on one surface of the flexible TPU fiber film; a vortex sensitive layer arranged on the other surface of the flexible TPU fiber film; The flexible TPU fiber film is prepared by electrospinning process, and the average diameter of the fiber is about 1.5 μm; The copper electrode lead is prepared by magnetron sputtering technology, which includes circular end parts at both ends and a middle connecting line connecting the two circular end parts, and the circular end parts are provided with through holes; The vortex sensitive layer comprises a composite material of carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and dodecylbenzenesulfonic acid doped polyaniline (DBSA-PANI), and the pattern is a multi-turn spiral with a preset line width and pitch, which can stimulate the electric eddy current effect; and one end of the vortex sensitive layer is electrically connected with one circular end part of the copper electrode lead.

2. The method for preparing the vortex-type flexible fiber membrane with intermittent ammonia measurement function as described in claim 1, characterized in that, It comprises the following steps: (1) Preparation of flexible TPU fiber film: N,N-dimethylformamide (DMF) is used as solvent to prepare TPU solution with certain concentration, and TPU is fully dissolved after magnetic stirring, then high pressure electrospinning treatment is carried out in constant temperature and humidity environment, and finally flexible TPU fiber film is obtained; (2) Preparation of copper electrode lead: the flexible TPU fiber film is cleaned with ethanol and deionized water by ultrasonic, and then cut into a rectangle with a length of 50 mm and a width of 40 mm after drying; an electrode mask with a length of 50 mm, a width of 40 mm and a thickness of 0.1 mm is covered on the surface of the flexible TPU fiber film, and copper layer is deposited on the surface by magnetron sputtering process; the electrode mask is removed to obtain the copper electrode lead; (3) Preparation of through hole: the center of the circular end part of the copper electrode lead is perforated with a needle tip wetted with DMF to form a through hole with a hole diameter of 0.5 mm; (4) Preparation of MWCNT-COOH and DBSA-PANI composite dispersion liquid: sodium dodecylbenzenesulfonate (SDBS) is added to deionized water, and it is dissolved by magnetic stirring; MWCNT-COOH is added to the above SDBS aqueous solution, which is first treated by ultrasonic for 2 hours, and then continuously stirred for 12 hours; finally, DBSA-PANI is added, and after stirring for 30 minutes, the composite dispersion liquid of MWCNT-COOH and DBSA-PANI is obtained; (5) Forming vortex sensitive layer: a spiral mask is covered on the surface of the flexible TPU fiber film away from the copper electrode lead, a magnet is placed at the bottom of the flexible TPU fiber film to ensure that the spiral mask is tightly attached to the flexible TPU fiber film without gap, and then placed on a constant temperature heating table; the high pressure gas of air compressor is connected to the spray gun to atomize and spray the MWCNT-COOH and DBSA-PANI composite dispersion liquid on the spiral mask window area, and the distance between the spray gun and the flexible TPU fiber film and the single spraying time are controlled, and after the solvent is volatilized, the spraying is repeated to the required thickness, and finally dried to form the vortex sensitive layer.

3. The preparation method of the vortex flexible fiber film with gap ammonia gas measurement function according to claim 2, characterized in that: In step (1), the mass fraction of the TPU solution is 59%, and the high-voltage electrostatic spinning process parameters are: ambient temperature 35°C, relative humidity 30% RH, positive voltage 16.2 kV, negative voltage 1.53 kV, spinning distance 24 cm, solution propelling rate 0.5 mL / h, receiving roller rotating speed 150 r / min, and spinning time 10 hours; In step (2), the process parameters of the magnetron sputtering are as follows: base vacuum 3×10 -4 Pa, argon flow rate 42 sccm, sputtering power 150 W, sample table rotation speed 3 r / min, sputtering time 600 s; In step (4), the use amounts of the components of the MWCNT-COOH and DBSA-PANI composite dispersion liquid are: sodium dodecyl benzene sulfonate 0.040 g, deionized water 40 mL, carboxylated multi-walled carbon nanotube 0.040 g, and dodecyl benzene sulfonic acid doped polyaniline 0.100 g; In step (5), the size of the spiral mask is 50 mm in length, 40 mm in width, and 0.1 mm in thickness, the line width and the line spacing are both 0.5 mm, and the number of turns is 10 turns; and the pneumatic spraying process parameters are: spraying gun caliber 0.2 mm, spraying air pressure 0.5 MPa, and spraying distance 15 cm.

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