Polyaniline-(silver / polyamideimide) Conductive Composite Material, Preparation Method Thereof and Stoma Abdominal Belt

Abstract

The present invention discloses a polyaniline-(silver / polyamideimide) conductive composite material, a preparation method thereof and a stoma abdominal belt. The method includes: preparing a silver / polyamideimide composite material precursor solution; preparing a silver / polyamideimide conductive composite material thin film with controllable morphology; performing surface modification on the obtained thin film; carrying out in-situ polymerization growth of polyaniline on the thin film; cleaning and drying the obtained microstructured polyaniline-(silver / polyamideimide) conductive composite film. The process of the present invention is controllable. The in-situ growth of silver is used to enhance the mechanical properties of the polyamideimide matrix material, so that the matrix material can better resist plastic deformation. The microstructured composite conductive film prepared thereby has excellent pressure sensing recovery and stability. A pressure sensor array assembled by multiple sensors can effectively monitor the spatial distribution of pressure. When applied to the opening of the stoma abdominal belt, it can effectively prevent parastomal hernia.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of composite conductive materials, and particularly relates to a polyaniline-(silver / polyamideimide) conductive composite material, a preparation method thereof, and an application thereof, which can be used for monitoring the pressure distribution at the opening of a stoma abdominal belt. Background Art

[0002] In the past few decades, flexible pressure sensors have made great progress. However, since the current mainstream flexible sensors all use elastomers such as thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) as matrix materials, creep is likely to occur during the pressure loading process, resulting in problems such as sensor signal drift and poor recoverability. Therefore, it is necessary to select a more suitable matrix material to improve the stability of the sensor. On the other hand, through the design and optimization of the microstructure, during the elastic deformation of the microstructure under pressure, the contact area with the electrode can change faster, so that the sensor has a greater signal response, that is, higher sensitivity. At the same time, when the deformation of the microstructure is too large, plastic deformation occurs, resulting in the inability of the sensor signal to recover. Therefore, it is necessary to optimize both the mechanical properties of the matrix material and the design of the pressure-sensitive microstructure to improve the stability and recoverability of the sensor while ensuring high sensitivity.

[0003] A stoma abdominal belt is a special abdominal belt used to fix and protect intestinal stomas, which can help patients with intestinal stomas relieve discomfort and improve their quality of life. However, wearers cannot avoid some movements and actions that increase abdominal pressure, which may cause parastomal hernia. Therefore, if a high-performance flexible pressure sensor array can be integrated at the edge of the abdominal belt opening to monitor the pressure of the abdomen and the abdominal belt at the stoma in real time and efficiently in a distributed manner, and timely detect problems such as swelling at the stoma, it will have great significance for the prevention and timely detection of parastomal hernia.

[0004] For this reason, the present invention provides a pressure sensor based on a polyaniline-(silver / polyamideimide) conductive composite material. Polyamideimide has both the excellent anti-creep performance of polyimide and the excellent solubility of polyamide, and is a very strong engineering plastic. The present invention obtains a composite material by improving this material, and as a pressure-sensitive material, the sensor can have excellent sensitivity, stability and recoverability, and can be well applied to stoma abdominal belts. Summary of the Invention

[0005] The purpose of the present invention is to provide a polyaniline-(silver / polyamideimide) conductive composite material, a preparation method thereof, and a stoma abdominal belt in view of the deficiencies of the prior art.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A preparation method of a polyaniline-(silver / polyamideimide) conductive composite material, comprising the following steps:

[0008] (1) Preparation of a silver / polyamideimide composite material precursor solution

[0009] Dissolve polyamideimide in a first solvent and stir to dissolve, then add silver nitrate and stir to dissolve. Heat to cause in-situ decomposition of silver nitrate to obtain a precursor solution of the silver / polyamideimide composite material;

[0010] Preferably, the concentration of polyamideimide can usually be 10 wt%;

[0011] Preferably, the ratio η between the number of moles of added silver nitrate and the mass of polyamideimide can usually be: 0 < η < 1.5 mmol / g, preferably 0.176 mmol / g;

[0012] Preferably, the temperature for heating to cause decomposition of silver nitrate can usually be 80 °C, and the time is 24 hours.

[0013] The first solvent can be at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP).

[0014] (2) Preparation of a silver / polyamideimide composite material thin film with a micro-structure

[0015] Spin-coat the precursor solution on a template with a micro-structured female mold, and after drying, separate it from the template to obtain a silver / polyamideimide composite material thin film with a protruding micro-structure;

[0016] Preferably, the spin-coating speed can be 300 revolutions per minute, and the spin-coating time is 30 seconds;

[0017] Preferably, the drying temperature is 60 °C, and the drying time is 6 hours;

[0018] The template can be a template with a random micro-structure (such as sandpaper, etc.) or a template with a regular micro-structure array;

[0019] The regular micro-structure is a micro-cylinder array, a micro-hemisphere array, or a micro-ellipsoid array. After preparing the thin film, the surface of the thin film has the regular micro-structure; the diameter of the micro-cylinder is between 10 and 100 μm, and the height is between 10 and 100 μm; the diameter of the micro-hemisphere is between 10 and 100 μm, and the height is between 10 and 50 μm; the diameter of the micro-ellipsoid is between 10 and 100 μm, and the height is between 10 and 50 μm, and the period length of the array is between 20 and 200 μm; preferably, the period length of the micro-cylinder array, the micro-hemisphere array, or the micro-ellipsoid array is 100 μm;

[0020] Preferably, the diameter of the micro-cylinder is 25 μm and the height is 25 μm;

[0021] Preferably, the diameter of the micro-hemisphere is 25 μm and the height is 12.5 μm;

[0022] Preferably, the diameter of the micro-ellipsoid is 25 μm and the height is 12.5 μm.

[0023] (3) Surface treatment of silver / polyamideimide composite film

[0024] The dried composite film with microstructures is treated with ultraviolet-ozone or oxygen plasma, and the treated film is soaked in a solution containing a surface modifier.

[0025] Preferably, the treatment time with ultraviolet-ozone or oxygen plasma is 4 minutes;

[0026] Preferably, the concentration of aminopropyltriethoxysilane (APTES) is 1 mL per 10 mL of ethanol;

[0027] Preferably, the film is soaked in an ethanol solution of a surface modifier such as aminopropyltriethoxysilane (APTES) for 2 hours.

[0028] (4) Preparation of aniline monomer solution and oxidant solution

[0029] Aniline monomer and citric acid are dissolved in water to prepare an acidic aniline solution with a certain concentration; a certain mass of ammonium persulfate is weighed and dissolved in water, and the concentration of the oxidant solution is the same as that of the aniline monomer solution;

[0030] Preferably, the concentration of aniline monomer can be 0.02 mol / L and the concentration of citric acid can be 0.5 mol / L.

[0031] (5) In-situ polymerization growth of polyaniline on the surface of silver / polyamideimide composite film

[0032] After washing the surface-modified microstructured silver / polyamideimide composite film with deionized water, it is soaked in an acidic aniline monomer solution and stored in a low-temperature environment. At the same time, the ammonium persulfate solution is also stored in a low-temperature environment. Subsequently, an equal volume of ammonium persulfate is mixed with the aniline monomer solution in which the silver / polyamideimide composite film is soaked and stirred evenly, and then stored in a low-temperature environment. After taking out the composite film, it is washed and dried to obtain a microstructured polyaniline-(silver / polyamideimide) composite conductive film;

[0033] Preferably, the low-temperature environment is usually 0-6°C. By carrying out a slow reaction in a low-temperature environment, it is possible to avoid a too-fast reaction that generates a large amount of free impurities and affects the performance of the product.

[0034] The microstructured polyaniline-(silver / polyamideimide) conductive composite film prepared by the present invention has excellent resistance to plastic deformation and can be used as a sensitive material in pressure sensors, enabling the sensors to have excellent sensitivity, stability, and recoverability.

[0035] (6) Assembly of the pressure sensor

[0036] A single pressure sensor consists of a substrate with interdigital electrodes, a microstructured polyaniline-(silver / polyamideimide) conductive film, and a packaging layer. In addition, multiple sensors can be connected in a common cathode or common anode connection mode and appropriately arranged in space according to needs to form a pressure sensor array; the non-common electrode ends of each sensor are connected to signal acquisition devices;

[0037] Preferably, the shape and size of the single pressure sensor can be adjusted according to the actual application scenario;

[0038] Preferably, the spatial distribution of each pressure sensor in the pressure sensor array can be adjusted according to the actual application scenario.

[0039] Advantages of the present invention:

[0040] In the present invention, the in-situ decomposition of silver nitrate is used to generate silver nanoparticles to further enhance the mechanical properties of polyamideimide, thereby enhancing its ability to resist plastic deformation as the matrix of the pressure-sensitive material, and further improving the stability and recoverability of the sensor signal. The template method is used to prepare a silver / polyamideimide composite film with a controllable morphology and a microstructured surface, and a polyaniline conductive layer is grown on the surface by chemical in-situ polymerization, making the preparation of the sensor more controllable in terms of consistency and repeatability. Generally speaking, the present invention realizes the controllable preparation of the microstructured polyaniline-(silver / polyamideimide) composite conductive film, and has great potential as a flexible pressure sensing material with high sensitivity and high stability. The sensor array based on this material can sense the spatial distribution of pressure. When integrated at the opening of a stoma abdominal belt, it can effectively monitor the pressure at different positions between the abdomen and the abdominal belt at the stoma in real time, and has a positive application prospect for the prevention and timely detection of incisional hernia. Description of the drawings

[0041] Figure 1 Shows the effect of the concentration of added silver nitrate on the mechanical properties of the silver / polyamideimide composite material;

[0042] Figure 2SEM images of different polyaniline-(silver / polyamideimide) composite conductive films prepared in Example 2;

[0043] Figure 3 SEM images of microstructured polyaniline-(silver / polyamideimide) composite conductive films prepared using the irregular protrusions on the sandpaper surface as templates;

[0044] Figure 4 Mechanical sensing properties of microstructured polyaniline-polyamideimide composite conductive films (with silver addition of 0) prepared using the irregular protrusions on the sandpaper surface as templates;

[0045] Figure 5 Mechanical sensing properties of microstructured polyaniline-(silver / polyamideimide) composite conductive films prepared using the irregular protrusions on the sandpaper surface as templates;

[0046] Figure 6 Optical microscope images of microstructured polyaniline-(silver / polyamideimide) composite conductive films prepared using artificial regular microstructure templates;

[0047] Figure 7 Mechanical sensing properties of microstructured polyaniline-(silver / polyamideimide) composite conductive films prepared using artificial regular microstructures (microcylinder arrays, microellipsoid arrays, microhemisphere arrays) as templates;

[0048] Figure 8 Schematic structural diagram of a pressure sensor prepared using a microstructured polyaniline-(silver / polyamideimide) composite conductive film;

[0049] Figure 9 Assembly diagram and pressure sensing effect diagram of a pressure sensor array based on a polyaniline-(silver / polyamideimide) composite conductive film with a microhemisphere structure on a stoma abdominal belt. Detailed implementation manners

[0050] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0051] The present invention uses polyamide-imide as the matrix, and further strengthens the mechanics of polyamide-imide by in-situ growth of silver nanoparticles to increase its modulus. At the same time, the silver nanoparticles and the imino group of polyamide-imide improve the interfacial bonding force through chelation, which can improve the mechanical stability of the silver / polyamide-imide composite material. Further, a polyaniline conductive layer is originally grown on the surface of the silver / polyamide-imide composite film with a specially designed microstructure to prepare a high-performance polyaniline-(silver / polyamide-imide) composite conductive and pressure-sensitive material. As a sensitive layer material, this material can be used to prepare a high-performance flexible pressure sensor, which can be used for monitoring local physiological sign signals in vivo such as pulse, heart rate, intracranial pressure, etc. The present invention provides a stoma abdominal belt based on this material, which can effectively monitor the pressure at different positions between the abdomen at the stoma and the abdominal belt, and can timely detect and prevent the occurrence of incisional hernia.

[0052] In the following examples, the method for testing the mechanical properties of the silver / polyamide-imide composite material is as follows:

[0053] According to GB13022-91, the precursor solution of the silver / polyamide-imide composite material is dried in a Type II dumbbell-shaped mold to obtain a dumbbell-shaped film specimen. A universal testing machine is used to conduct a tensile test on the composite material film specimen at a tensile speed of 5 mm / min to obtain a stress-strain curve, and the Young's modulus is obtained by linearly fitting the elastic stage.

[0054] In the following examples, the method for testing the pressure sensing of the composite conductive film is as follows:

[0055] After cutting the composite conductive film into 1 cm × 1 cm square pieces, they are placed on the etched ITO glass (an insulating region with a width of 1 mm is etched on the complete ITO coating, and the positive and negative electrodes of the digital source meter are respectively connected to both sides of the insulating region). A push-pull force gauge is used to apply pressure to the conductive film, and a digital source meter is used to read the current value of the composite conductive film under this pressure. The stability and recoverability evaluation of the composite conductive film as a pressure sensing material can be obtained by comparing the consistency of the current signal values under the same pressure load during the loading process and the unloading process.

[0056] Example 1

[0057] Effect of different silver addition amounts on the mechanical properties of silver / polyamide-imide

[0058] The preparation method of the silver / polyaniline composite conductive film described above includes the following steps:

[0059] (1) Take 6 containers, label them as No. 1-6, respectively weigh 1 g of polyamide-imide, and respectively add 10 mL of DMF, and stir until completely dissolved;

[0060] (2) Add 0, 0.015, 0.030, 0.060, 0.120, and 0.240 g of silver nitrate into Nos. 1 - 6 respectively, and stir until completely dissolved;

[0061] (3) Wrap the above solution with tin foil to avoid light, and continuously stir at 80 °C for 24 hours to obtain a silver / polyamideimide composite material precursor solution;

[0062] (4) Pour the above precursor solution into a Type II dumbbell-shaped mold of GB6672, and dry it at 60 °C for 6 hours to obtain a film specimen;

[0063] (5) Conduct a tensile test on the film specimen to obtain the influence of the silver addition amount on the mechanical properties of the composite material. As Figure 1 shown, when the silver nitrate addition amount is 0.030 g, that is, the corresponding silver addition amount is 0.176 mmol / g, the Young's modulus of the composite material is the highest, and it can provide the strongest resistance to deformation when used as the matrix of the pressure-sensitive material.

[0064] Example 2

[0065] Compare the influence of surface treatment and non-surface treatment on the surface morphology of the polyaniline-(silver / polyamideimide) composite conductive film. Its preparation method includes the following steps:

[0066] (1) Take a container, weigh 1 g of polyamideimide, add 10 mL of DMF, and stir until completely dissolved;

[0067] (2) Add 0.030 g of silver nitrate into the polyamideimide solution, wrap it with tin foil to avoid light, and stir until completely dissolved;

[0068] (3) Wrap the above solution with tin foil to avoid light, and continuously stir at 80 °C for 24 hours to obtain a silver / polyamideimide composite material precursor solution;

[0069] (4) Spin-coat the above precursor solution on a glass substrate, and after drying, separate it from the glass substrate to obtain a flat and smooth silver / polyamideimide composite material film;

[0070] (5) Measure 10 mL of ethanol, add 1 mL of aminopropyltriethoxysilane, and stir evenly;

[0071] (6) Take two composite material films of the same size in step (4). Treat one of them with ultraviolet-ozone for 4 minutes, then soak it in the solution in step (5) for 2 hours, and wash it with deionized water. Do not treat the other one;

[0072] (7) Preparation of aniline monomer solution: Weigh citric acid monohydrate and add it to deionized water and stir to dissolve it to a concentration of 0.05 mol / L. Then add aniline monomer and stir to dissolve it to a concentration of 0.2 mol / L. Additionally, prepare an ammonium persulfate solution with a concentration of 0.2 mol / L.

[0073] (8) Immerse the surface-modified and un-surface-modified silver / polyamideimide composite membranes in the aniline monomer solution (10 mL) prepared in (7), and place them in the refrigerator for 2 hours. Place the ammonium persulfate solution in (7) in the refrigerator for 2 hours.

[0074] (9) Take 10 mL of the refrigerated ammonium persulfate solution, mix it with the aniline monomer solution in which the silver / polyamideimide composite membrane is immersed, and place it in the refrigerator for 12 hours to enable in-situ polymerization growth of polyaniline on the surface of the silver / polyamideimide composite membrane.

[0075] (10) Take out the polyaniline-(silver / polyamideimide) composite conductive membrane, wash it with deionized water, and dry it in a vacuum drying oven.

[0076] Cut small pieces from the prepared samples, paste them on carbon adhesive tapes, sputter gold, and then place them in a field emission scanning electron microscope to observe the morphology of the irregular microstructures on the surface. Through large-area observation of multiple samples, it is found that the polyaniline grown on the surface of the silver / polyamideimide without surface treatment is very uneven, and there is free polyaniline, which is not conducive to the consistency of device performance. After surface treatment, the polyaniline grown on the surface of the silver / polyamideimide is flat and uniform, as Figure 2 shown, which is beneficial to improving the stability of sensor signals.

[0077] Example 3

[0078] Comparison of the force-electric sensing stability of composite conductive membranes with irregular microstructures with and without added silver, and its preparation method includes the following steps:

[0079] (1) Take two containers A and B, and respectively weigh 1 g of polyamideimide and add 10 mL of DMF, and stir until completely dissolved.

[0080] (2) Add 0.030 g of silver nitrate to the polyamideimide solution in A, and do not add silver nitrate to B. Wrap them with tin foil to avoid light, and stir until the silver nitrate in A is completely dissolved.

[0081] (3) Wrap the above solutions with tin foil to avoid light, and continuously stir at 80 °C for 24 hours to obtain a silver / polyamideimide composite precursor solution and a pure polyamideimide solution.

[0082] (4) Spin-coat the above solutions on a #400 sandpaper template respectively, and after drying, separate them from the sandpaper template to obtain a silver / polyamideimide composite film and a pure polyamideimide film with irregular protruding microstructures;

[0083] (5) Measure 10 mL of ethanol, add 1 mL of aminopropyltriethoxysilane, and stir evenly;

[0084] (6) Treat the microstructured surfaces of the two films in step (4) with ultraviolet-ozone for 4 minutes. After soaking the treated films in the solution in step (5) for 2 hours, wash them with deionized water;

[0085] (7) Prepare an aniline monomer solution: Weigh citric acid monohydrate and add it to deionized water and stir to dissolve it to a concentration of 0.05 mol / L. Then add aniline monomer and stir to dissolve it to a concentration of 0.2 mol / L; Prepare an ammonium persulfate solution with a concentration of 0.2 mol / L;

[0086] (8) Immerse the surface-modified microstructured silver / polyamideimide composite film and the pure polyamideimide film in the aniline monomer solution (10 mL) prepared in (7), and place them in the refrigerator for 2 hours; Place the ammonium persulfate solution in (7) in the refrigerator for 2 hours;

[0087] (9) Take 10 mL of the refrigerated ammonium persulfate solution, mix it with the aniline monomer solutions respectively immersed with the microstructured silver / polyamideimide composite film and the pure polyamideimide film, and place them in the refrigerator for 12 hours to enable in-situ polymerization growth of polyaniline on the film surface;

[0088] (10) Take out the polyaniline-(silver / polyamideimide) and polyaniline-polyamideimide composite conductive films, wash them with deionized water and dry them in a vacuum drying oven;

[0089] Cut small pieces from the prepared samples, paste them on carbon adhesive tapes, spray gold and then place them in a field emission scanning electron microscope to observe the morphology of the irregular surface microstructures. It can be seen that the microstructures obtained using sandpaper as a template are locally irregular but overall uniform, as Figure 3 shown. Conduct pressure sensing tests, as Figure 4 and Figure 5 shown. For the pressure sensor based on polyaniline-polyamideimide without adding silver, there is serious signal drift, and the consistency of loading and unloading is very poor. After introducing an appropriate amount of silver to strengthen the polyamideimide, compared with pure polyamideimide, the signal drift of the sensor is greatly inhibited, the signal stability is greatly improved, and the consistency of loading and unloading is significantly improved.

[0090] Example 4

[0091] Preparation method of a polyaniline-(silver / polyamideimide) composite conductive film with artificial regular microstructures, comprising the following steps:

[0092] (1) Take a container, weigh 1 g of polyamideimide, add 10 mL of DMF, and stir until completely dissolved;

[0093] (2) Add 0.030 g of silver nitrate to the polyamideimide solution, wrap it with tinfoil to avoid light, and stir until completely dissolved;

[0094] (3) Wrap the above solution with tinfoil to avoid light, continuously stir at 80 °C for 24 hours to obtain a silver / polyamideimide composite material precursor solution;

[0095] (4) Spin-coat the above precursor solution on a template with artificial regular microstructures (microcylinder arrays, microhemisphere arrays, and microellipsoid arrays respectively), the period length of the arrays is 100 μm, where the diameter of the microcylinders is 25 μm and the height is 25 μm, the diameter of the microhemispheres is 25 μm and the height is 12.5 μm, and the diameter of the microellipsoids is 25 μm and the height is 25 μm;

[0096] (5) After drying the precursor solution, separate it from the template to obtain a silver / polyamideimide composite material film with artificial regular microstructures;

[0097] (6) Measure 10 mL of ethanol, add 1 mL of aminopropyltriethoxysilane, and stir evenly;

[0098] (7) Treat the microstructured surface of the composite material film in step (5) with ultraviolet-ozone for 4 minutes, soak the treated film in the solution in step (6) for 2 hours, and then wash it with deionized water;

[0099] (8) Prepare an aniline monomer solution: Weigh citric acid monohydrate, add it to deionized water and stir to dissolve, with a concentration of 0.05 mol / L, add aniline monomer, and stir to dissolve, with a concentration of 0.2 mol / L; separately prepare an ammonium persulfate solution with a concentration of 0.2 mol / L;

[0100] (9) Immerse the surface-modified microstructured silver / polyamideimide composite material film in the aniline monomer solution (10 mL) prepared in (8), and place it in the refrigerator for 2 hours; place the ammonium persulfate solution in (8) in the refrigerator for 2 hours;

[0101] (10) Take 10 mL of the refrigerated ammonium persulfate solution, mix it with the aniline monomer solution soaked with the microstructured silver / polyamideimide composite material film, and place it in the refrigerator for 12 hours to enable in-situ polymerization growth of polyaniline on the surface of the microstructured silver / polyamideimide composite material film;

[0102] (11) Take out the polyaniline-(silver / polyamideimide) composite conductive film, wash it with deionized water, and then dry it in a vacuum drying oven.

[0103] Cut small pieces from the prepared samples, paste them on glass slides, and place them in an optical microscope to observe the morphology of the surface microstructure array. As Figure 6 shown, the prepared microcylinder array, microhemisphere array, and microellipsoid array have regular and complete structures, which makes the performance of the sensor more controllable. Conduct pressure sensing tests on the pressure-sensitive films with these three different microstructures. As Figure 7 shown, the sensor with the microcylinder array has relatively serious signal drift, resulting in poor signal consistency during loading-unloading, while the sensors with the microellipsoid array and microhemisphere array still have high signal stability and recoverability even under large pressures, and their performance is excellent. Among the three structures, the microhemisphere array has the highest sensitivity and the smallest signal noise, and overall it is the micro-structure with the best performance.

[0104] Example 5

[0105] The application method of the pressure sensor array based on the polyaniline-(silver / polyamideimide) composite conductive film in a stoma abdominal belt includes the following steps:

[0106] (1) Take a container, weigh 1 g of polyamideimide, add 10 mL of DMF, and stir until completely dissolved.

[0107] (2) Add 0.030 g of silver nitrate to the polyamideimide solution, wrap it with tin foil to avoid light, and stir until completely dissolved.

[0108] (3) Wrap the above solution with tin foil to avoid light, and continuously stir it at 80 °C for 24 hours to obtain a silver / polyamideimide composite material precursor solution.

[0109] (4) Spin-coat the above precursor solution on a template with artificial regular microstructures (microhemisphere array), where the period length of the array is 100 μm, the diameter of the microhemisphere is 25 μm, and the height is 12.5 μm.

[0110] (5) After drying the precursor solution, separate it from the template to obtain a silver / polyamideimide composite material film with a microhemisphere array structure.

[0111] (6) Measure 10 mL of ethanol, add 1 mL of aminopropyltriethoxysilane, and stir evenly.

[0112] (7) Treat the surface with microstructures of the composite material film in step (5) with ultraviolet-ozone for 4 minutes. After soaking the treated film in the solution in step (6) for 2 hours, wash it with deionized water.

[0113] (8) Preparation of aniline monomer solution: Weigh citric acid monohydrate and add it to deionized water and stir to dissolve it to a concentration of 0.05 mol / L. Then add aniline monomer and stir to dissolve it to a concentration of 0.2 mol / L. Additionally, prepare an ammonium persulfate solution with a concentration of 0.2 mol / L.

[0114] (9) Immerse the surface-modified microstructured silver / polyamideimide composite material membrane in the aniline monomer solution (10 mL) prepared in (8), and place it in the refrigerator for 2 hours. Place the ammonium persulfate solution in (8) in the refrigerator for 2 hours.

[0115] (10) Take 10 mL of the refrigerated ammonium persulfate solution, mix it with the aniline monomer solution in which the microstructured silver / polyamideimide composite material membrane is immersed, and place it in the refrigerator for 12 hours to enable in-situ polymerization growth of polyaniline on the surface of the microstructured silver / polyamideimide composite material membrane.

[0116] (11) Take out the polyaniline-(silver / polyamideimide) composite conductive membrane, wash it with deionized water, and dry it in a vacuum drying oven.

[0117] (12) Cut the composite conductive membrane in step (11) into circular pieces with a diameter of 8 mm, and assemble them into a pressure sensor. The side of the conductive membrane with microstructures should face the electrode. Figure 8

[0118] (13) Take 6 pressure sensors obtained in step (12), perform a common cathode connection, and use the remaining electrodes as signal reading terminals. Distribute them evenly at the opening of the stoma abdominal belt in the manner shown in Figure 9 to form a sensor array for monitoring the pressure distribution at the opening.

[0119] As Figure 9 shown, each pixel point of the sensor array can independently monitor the pressure. Parastomal hernia will cause further extrusion between the abdomen and the abdominal belt, thereby loading the pressure sensor. By using the distributed sensor array to monitor the pressure at the abdominal and stoma belt areas in real time and accurately, it is expected to provide a new and positive means for the prevention and timely detection of parastomal hernia.​

Claims

1. A method for preparing a polyaniline-(silver / polyamide-imide) conductive composite material, characterized in that: The following steps are involved: Step 1: Preparation of silver / polyamide-imide composite precursor solution The polyamide-imide is dissolved in a solvent and stirred to dissolve, and then silver nitrate is added and stirred to dissolve, and the silver nitrate is heated to decompose in situ to obtain a precursor solution of a silver / polyamide-imide composite material; the solvent is at least one of N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP); Step 2: Preparation of silver / polyamide-imide composite film with microstructure Spin coating the precursor solution described in step 1 on a template having a microstructure concave mold, and separating from the template after drying to obtain a silver / polyamide-imide composite film having a protruding microstructure; Step 3: Surface treatment of silver / polyamide-imide composite film Treating the composite film with microstructure in step 2 with ultraviolet-ozone or oxygen plasma, and immersing the treated film in an ethanol solution of a surface modifier; Step 4: Preparation of aniline monomer solution and oxidant solution Aniline monomer and doping acid are dissolved in water to prepare an acidic aniline solution; a certain mass of oxidant is weighed and dissolved in water, and the concentration of the oxidant solution is the same as that of the aniline monomer solution; Step 5: In-situ polymerization growth of polyaniline on the surface of silver / polyamide-imide composite film The surface-modified silver / polyamide-imide composite film in step 3 is washed with deionized water, and then immersed in the acidic aniline solution described in step 4. The solution and the oxidant solution are simultaneously stored in an environment of 0-6°C. Subsequently, an equal volume of the oxidant solution and the acidic aniline solution in which the silver / polyamide-imide composite film is immersed are mixed and stirred evenly, and then stored in an environment of 0-6°C. The silver / polyamide-imide composite film is taken out, washed, and dried to obtain a polyaniline-(silver / polyamide-imide) conductive film with a microstructure.

2. The method for preparing the polyaniline-(silver / polyamide-imide) conductive composite material according to claim 1, characterized in that: The value range of the ratio η of the molar number of silver nitrate to the mass of polyamide-imide in the step 1 is: 0<η<1.5 mmol / g.

3. The method for preparing the polyaniline-(silver / polyamide-imide) conductive composite material according to claim 1, characterized in that: The Young's modulus of the silver / polyamide-imide conductive composite material in step 2 is in the range of 2-7.5 GPa.

4. The method for preparing the polyaniline-(silver / polyamide-imide) conductive composite material according to claim 1, characterized in that: The template in step 2 is a template with a random microstructure or a template with a regular microstructure.

5. The method for preparing the polyaniline-(silver / polyamideimide) conductive composite material according to claim 4, characterized in that: The regular microstructure is a micro-cylinder array, a micro-hemispherical array or a micro-ellipsoidal array.

6. The method for preparing the polyaniline-(silver / polyamideimide) conductive composite material according to claim 5, characterized in that: The diameter of the micro-cylinder is between 10 and 100 µm, and the height is between 10 and 100 µm; the diameter of the micro-hemisphere is between 10 and 100 µm, and the height is between 10 and 50 µm; the diameter of the micro-ellipsoid is between 10 and 100 µm, and the height is between 10 and 50 µm, and the period length of the array is between 20 and 200 µm.

7. A microstructured polyaniline-(silver / polyamide-imide) conductive composite material, characterized in that: The method is prepared by the method according to any one of claims 1 to 6.

8. A flexible pressure sensor, characterized in that: The conductive composite material according to claim 7 is used as a pressure-sensitive material, comprising a substrate with an electrode, a microstructured polyaniline-(silver / polyamide-imide) conductive composite material film and an encapsulation layer, wherein the microstructure of the microstructured polyaniline-(silver / polyamide-imide) conductive composite material film is in contact with the electrode on the substrate.

9. A stoma belly band, characterized in that: On the abdominal band, a number of flexible pressure sensors as described in claim 8 are arranged around the stoma opening. All pressure sensors are connected in a common cathode or common anode manner and are arranged around the stoma opening to form a pressure sensor array; the non-common electrode end of each sensor is connected to a signal acquisition device.

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