A method for preparing a wearable potentiometric ion sensor based on conductive polymer nanofiber membranes

Abstract

The application relates to a method for preparing a wearable potential ion sensor based on a conductive polymer nanofiber membrane and belongs to the field of electrochemical sensing. The method mainly comprises the following steps: (1) conductive polymer monomer solution and initiator-crosslinking agent mixed solution are successively drop-coated on the surface of an electrode, the latter induces monomer assembly polymerization, a conductive polymer nanofiber membrane is obtained, and drying is performed; (2) an ion-selective membrane dispersion liquid is prepared according to a certain proportion and is dropwise added to the electrode, and film drying is performed; (3) after the prepared electrode is dried overnight in the dark, the electrode is placed in a prepared standard ion solution (to-be-measured ion) for pretreatment; and (4) the electrode is placed in ion solutions with different concentrations for testing, the relationship between ion concentration and voltage is obtained, a standard curve and a linear equation are obtained, and monitoring of ion concentration in sweat is realized. The wearable potential ion sensor prepared by the method can realize high-sensitivity real-time monitoring of ions in sweat.

Description

Technical fields:

[0001] This invention relates to the preparation of a wearable potential ion sensor using a conductive polymer nanofiber membrane as an ion-electron transduction layer and its application in sweat monitoring, belonging to the field of electrochemical sensing. Background technology:

[0002] Ions are crucial for maintaining normal cellular function. Ions such as sodium, potassium, and calcium participate in important biochemical processes like cell membrane potential regulation and cell signal transduction. However, excessively high or low ion concentrations can lead to dysfunction and even failure of multiple organs, including the nervous, cardiovascular, and muscular systems. Real-time, continuous monitoring of changes in the body's ion levels is essential for disease prevention. Blood tests can accurately determine ion concentrations. However, this method carries risks of trauma and infection, and it's difficult to record changes in real time, potentially missing the optimal treatment window in the early stages of disease. Therefore, developing a non-invasive, continuous sensor for monitoring body ion concentrations would optimize the use of medical resources and safeguard human health.

[0003] Wearable potentiometric ion sensors (WPIS) can acquire relevant health information in real time by detecting active components in secretions such as sweat. However, the ion concentration in sweat is much lower than in blood. Therefore, improving the sensitivity and detection limit of WPIS is key to achieving accurate monitoring of ions in sweat. The core of WPIS performance is the solid-state contact ion-selective electrode, in which the ion-electron conversion membrane is crucial for signal transmission. Conductive polymers, with their ability to simultaneously conduct ions and electrons, solution processability, and ease of control, are widely used in the ion-electron conversion membrane of WPIS. However, conventionally prepared conductive polymer membranes are composed of aggregated conductive polymer nanoparticles, which increases the resistance to electron / ion mass transfer and reduces the active surface area, resulting in low sensitivity and detection limits that cannot meet the requirements for low-concentration ion testing. If conductive polymers could be fabricated into nanofibers similar to wires, it is hoped that the electron / ion mass transfer within the conductive polymer membrane could be enhanced and its active surface area increased, resulting in a WPIS with high sensitivity and a wide detection range for long-term monitoring of potassium in sweat. + Changes in concentration (Kim, HJ, Adsorption 2019, 25, 1259-1269).

[0004] This invention employs supramolecular chemistry to control the self-assembly orientation of conductive polymers in situ, fabricating nanofiber-like conductive polymer films on flexible electrode substrates. By depositing an ion-selective permeable membrane, a WPIS (Potentially Permeable Sensor) was obtained for real-time monitoring of ion concentration changes in sweat. During the polymer polymerization process, a 'quadrupole' type crosslinking agent was used to regulate the unidirectional growth of chain segments, resulting in nanofiber-like conductive polymer chains with high aspect ratios. Simultaneously, the crosslinking agent doped the conductive polymer, increasing its conductivity. In testing, the ion-selective permeable membrane dedoped the conductive polymer film, reducing it and generating a potential difference. The high aspect ratio of the conductive polymer nanofibers enhances the electron / ion reaction and mass transfer rate during dedoping, improving the sensitivity and response time of the WPIS. By controlling the morphology of the conductive polymer chain segments, reducing the electron / ion mass transfer barrier, and increasing reaction sites, the sensor performance can be significantly improved. By measuring the relationship between potassium ion concentration and voltage for polypyrrole nanospheres (WPIS), the linear equation was obtained as y = 0.107 + 0.032x, and for polypyrrole nanofibers (WPIS), it was y = 0.227 + 0.062x. The slope of the equation represents the sensitivity, indicating that the optimized WPIS based on polypyrrole nanofibers at K... + A 62mV decade was achieved during testing. –1 High sensitivity, superior to the 32mV decade of polypyrrole nanospheres. –1 This WPIS has a wide detection range, namely 0.05-100mM (covering K in sweat). + (Concentration). This method has advantages such as mild preparation conditions and simple operation, and has important scientific value for promoting online e-healthcare. Summary of the Invention:

[0005] The purpose of this invention is to prepare a highly sensitive, wide-range, and low-limit ion-selective electrochemical membrane (WPIS) for continuous monitoring of ions in sweat. By inducing monomer assembly and polymerization with a 'quadrupole' type crosslinking agent and controlling the morphology of the conductive polymer, an ion-electron transduction membrane composed of nanofibers is constructed in situ on the surface of a flexible electrode. An ion-selective membrane is deposited on the surface of the conductive polymer membrane as the working electrode, and Ag / AgCl is used as the counter electrode to prepare the WPIS. The WPIS prepared by this method enables highly sensitive, fast-response real-time monitoring of ions in sweat.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] (1) Dissolve the conductive polymer monomer in a solvent and stir until fully dissolved to obtain monomer solution A; dissolve the initiator and the 'quadruple' crosslinking agent in a solvent and stir until fully dissolved to obtain solution B;

[0008] (2) Solution A and solution B are dropped onto the electrode respectively, and the two react on the electrode surface to obtain a conductive polymer nanofiber membrane; after drying in an oven, it is taken out.

[0009] (3) Prepare an ion-selective membrane dispersion according to a certain proportion;

[0010] (4) The ion-selective membrane dispersion prepared in step (3) is dropped onto the conductive polymer nanofiber membrane obtained in step (2) and dried to form a membrane;

[0011] (5) Dry the prepared electrode in the dark overnight, and then pretreat it in the prepared 0.1M analyte solution;

[0012] (6) Place the electrode from step (5) in solutions of ions to be tested with different standard concentrations to obtain the relationship between ion concentration and voltage, and obtain the standard curve and linear equation to achieve ion concentration monitoring.

[0013] The conductive polymer monomer in step (1) of this invention is selected from pyrrole, aniline or thiophene, and the monomer has a mass fraction of 10% to 30% in solution A; the initiator can be ammonium persulfate (APS) or ferric chloride (FeCl3), and its mass fraction in solution B is 0.1-1%; the 'quadruple' crosslinking agent is selected from copper tetrasulfonate phthalocyanine (CuPcTs), zinc tetrasulfonate phthalocyanine, iron tetrasulfonate phthalocyanine, zinc tetracarboxylate phthalocyanine or tetraaminoferrophthalocyanine, etc., and its molar concentration in solution B is 7μM to 10μM.

[0014] In step (2) of this invention, the volume ratio of the reaction between solution A and solution B is 1:2.

[0015] In step (3) of this invention, the ion-selective membrane dispersion formulation consists of a certain proportion of polyvinyl chloride, dioctyl sebacate, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and different ion carriers (K). + carrier, NH4 + carrier, Na + carrier, Ca 2+ support, Cu 2+ carrier, Cl - carrier or Pb 2+ The carriers, etc., are dissolved in cyclohexanone; the mass percentages of polyvinyl chloride, dioctyl sebacate, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and the ion carrier are 32-35%: 62-65%: 0.4-0.6%: 1-3%; different ion carriers are used to test different ions.

[0016] The ion-selective electrode sensor prepared by this invention can be directly worn on the skin to detect a wide range of ion concentrations under different environments (such as sweat), exhibiting high sensitivity and fast response time. The technical principle of this invention is as follows:

[0017] This invention utilizes a 'quadruple' crosslinking agent to control the polymerization orientation of conductive polymer monomers through supramolecular self-assembly, thereby obtaining a conductive polymer with nanofiber-like structures. This polymer is then fabricated into a film as an ion-electron transduction layer, with K0 deposited on its surface. + Isoselective membrane. During the test, K + The selectively permeable upper film interacts with the conductive polymer, doping (reducing) it and converting the ionic signal into an electronic signal. Electrons are then transported through the conductive polymer film to the electrode, generating a potential difference with the counter electrode. The magnitude of this potential difference is related to K. + Concentration-dependent. The constructed nanofiber conductive polymer can reduce ion / electron mass transfer resistance, increase active sites, improve ion-electron transduction efficiency, increase the sensitivity of WPIS, and improve response time, thus enabling the detection of low concentrations of K+ in sweat. + Real-time monitoring (etc.) Figure 1 (See the image below). Attached image description:

[0018] Figure 1 This is a schematic diagram of the sensing mechanism using conductive polymer nanofibers as the ion-electron transduction layer, as provided in an embodiment of the present invention. The upper part represents the spherical conductive polymer, and the lower part represents the nanofiber conductive polymer of the present invention. Figure 2 Field emission scanning electron microscope (FESEM) images of the conductive polymer nanofibers prepared according to embodiments of the present invention; a corresponds to the comparative example, and b corresponds to Example 1.

[0019] Figure 3 The diagram shows the dynamic response of the conductive polymer electrode prepared according to an embodiment of the present invention with the addition of ions. a corresponds to conductive polymer nanospheres, and b corresponds to conductive polymer nanofibers. Detailed Implementation

[0020] The present invention will be described in detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0021] Example 1:

[0022] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; add 0.137 g (1.2 mM) of ammonium persulfate initiator and 0.037 g (7.5 μM) of pyrrole.

[0023] Copper phthalocyanine-3,4′,4″,4″′-tetrasodium phthalocyanine (CuPcTs) crosslinking agent is dissolved in water and stirred until fully dissolved to obtain solution B;

[0024] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane. Figure 2 a);

[0025] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0026] (4) Polyvinyl chloride: dioctyl sebacate in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%

[0027] Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: K + A total of 100 mg of the four carriers was dissolved in 350 μL of cyclohexanone to prepare a sodium ion selective membrane dispersion.

[0028] (5) Add the potassium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0029] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M KCl solution.

[0030] (7) The electrode from step (6) was placed in KCl solutions of different concentrations for testing. The relationship between ion concentration and voltage was obtained, and a standard curve and linear equation were obtained as y = 0.227 + 0.062x. The WPIS of the obtained polypyrrole nanofiber membrane in KCl solution was measured. + A 62mV decade was achieved during testing. –1 With its high sensitivity, covering the range of 0.05-100mM (covering the potassium ion concentration in human sweat), it can monitor the potassium ion concentration in human sweat.

[0031] Example 2:

[0032] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; add 0.137 g (1.2 mmol) of ammonium persulfate initiator and 0.037 g (7.5 μM) of pyrrole.

[0033] Copper phthalocyanine-3,4′,4″,4″′-tetrasodium phthalocyanine (CuPcTs) crosslinking agent is dissolved in water and stirred until fully dissolved to obtain solution B;

[0034] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane.

[0035] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0036] (4) Polyvinyl chloride: dioctyl sebacate: sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: Na, in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%. + A sodium ion-selective membrane dispersion was prepared by dissolving the carrier in 350 μL of cyclohexanone.

[0037] (5) Add the sodium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0038] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M NaCl solution.

[0039] (7) The electrode in step (6) is placed in NaCl solutions of different concentrations for testing. The relationship between ion concentration and voltage is obtained, and a standard curve and linear equation are obtained to realize the monitoring of sodium ion concentration.

[0040] Example 3:

[0041] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; add 0.137 g (1.2 mmol) of ammonium persulfate initiator and 0.037 g (7.5 μM) of pyrrole.

[0042] Copper phthalocyanine-3,4′,4″,4″′-tetrasodium phthalocyanine (CuPcTs) crosslinking agent is dissolved in water and stirred until fully dissolved to obtain solution B;

[0043] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane.

[0044] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0045] (4) Polyvinyl chloride: dioctyl sebacate: sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: Ca, in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%. 2+ The carrier was dissolved in 350 μL of cyclohexanone to prepare a calcium ion selective membrane dispersion.

[0046] (5) Add the calcium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0047] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M CaCl2 solution.

[0048] (7) The electrode in step (6) is placed in CaCl2 solution of different concentrations for testing to obtain the relationship between ion concentration and voltage, and to obtain the standard curve and linear equation, so as to realize the monitoring of calcium ion concentration.

[0049] Example 4:

[0050] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; add 0.137 g (1.2 mmol) of ammonium persulfate initiator and 0.037 g (7.5 μM) of pyrrole.

[0051] Copper phthalocyanine-3,4′,4″,4″′-tetrasodium phthalocyanine (CuPcTs) crosslinking agent is dissolved in water and stirred until fully dissolved to obtain solution B;

[0052] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane.

[0053] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0054] (4) The following components are present in a mass percentage ratio of 32.8% : 64.7% : 0.5% : 2%: polyvinyl chloride : dioctyl sebacate : sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate : Cl - The carrier was dissolved in 350 μL of cyclohexanone to prepare a chloride ion selective membrane dispersion.

[0055] (5) The chloride ion selective membrane dispersion prepared in step (4) is added dropwise to the electrode obtained in step (3) and dried to form a membrane;

[0056] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M NaCl solution.

[0057] (7) The electrode in step (6) is placed in NaCl solutions of different concentrations for testing. The relationship between ion concentration and voltage is obtained, and a standard curve and linear equation are obtained to realize the monitoring of chloride ion concentration.

[0058] Example 5:

[0059] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; add 0.137 g (1.2 mmol) of ammonium persulfate initiator and 0.037 g (7.5 μM) of pyrrole.

[0060] Copper phthalocyanine-3,4′,4″,4″′-tetrasodium phthalocyanine (CuPcTs) crosslinking agent is dissolved in water and stirred until fully dissolved to obtain solution B;

[0061] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane.

[0062] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0063] (4) The following components are present in a mass percentage ratio of 32.8% : 64.7% : 0.5% : 2%: polyvinyl chloride : dioctyl sebacate : sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate : NH4 + The carrier was dissolved in 350 μL of cyclohexanone to prepare an ammonium ion-selective membrane dispersion.

[0064] (5) The chloride ion selective membrane dispersion prepared in step (4) is added dropwise to the electrode obtained in step (3) and dried to form a membrane;

[0065] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M NH4Cl solution.

[0066] (7) The electrode in step (6) is placed in NH4Cl solution of different concentrations for testing to obtain the relationship between ion concentration and voltage, and to obtain the standard curve and linear equation, so as to realize the monitoring of ammonium ion concentration.

[0067] Example 6:

[0068] (1) Dissolve 42 μL (1.2 mmol) of aniline in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; add 0.137 g (1.2 mmol) of ammonium persulfate initiator and 0.037 g (7.5 μM) of aniline.

[0069] Copper phthalocyanine-3,4′,4″,4″′-tetrasodium phthalocyanine (CuPcTs) crosslinking agent is dissolved in water and stirred until fully dissolved to obtain solution B;

[0070] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polyaniline nanofiber membrane;

[0071] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0072] (4) Polyvinyl chloride: dioctyl sebacate in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%

[0073] Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: K + A sodium ion-selective membrane dispersion was prepared by dissolving the carrier in 350 μL of cyclohexanone.

[0074] (5) Add the potassium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0075] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M KCl solution.

[0076] (7) The electrode in step (6) is placed in KCl solution of different concentrations for testing to obtain the relationship between ion concentration and voltage, and to obtain the standard curve and linear equation to realize the monitoring of potassium ion concentration.

[0077] Example 7:

[0078] (1) Dissolve 42 μL (1.2 mmol) of thiophene in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; add 0.137 g (1.2 mmol) of ammonium persulfate initiator and 0.037 g (7.5 μM) of thiophene.

[0079] Copper phthalocyanine-3,4′,4″,4″′-tetrasodium phthalocyanine (CuPcTs) crosslinking agent is dissolved in water and stirred until fully dissolved to obtain solution B;

[0080] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polythiophene nanofiber membrane.

[0081] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0082] (4) Polyvinyl chloride: dioctyl sebacate in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%

[0083] Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: K + A sodium ion-selective membrane dispersion was prepared by dissolving the carrier in 350 μL of cyclohexanone.

[0084] (5) Add the potassium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0085] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M KCl solution.

[0086] (7) The electrode in step (6) is placed in KCl solution of different concentrations for testing to obtain the relationship between ion concentration and voltage, and to obtain the standard curve and linear equation to realize the monitoring of potassium ion concentration.

[0087] Example 8:

[0088] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; dissolve 0.137 g (1.2 mmol) of ammonium persulfate initiator and 7.5 μM of zinc tetrasulfonate phthalocyanine crosslinking agent in water and stir until fully dissolved to obtain solution B;

[0089] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane.

[0090] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0091] (4) Polyvinyl chloride: dioctyl sebacate in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%

[0092] Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: K + A sodium ion-selective membrane dispersion was prepared by dissolving the carrier in 350 μL of cyclohexanone.

[0093] (5) Add the potassium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0094] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M KCl solution.

[0095] (7) The electrode in step (6) is placed in KCl solution of different concentrations for testing to obtain the relationship between ion concentration and voltage, and to obtain the standard curve and linear equation to realize the monitoring of potassium ion concentration.

[0096] Example 9:

[0097] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; dissolve 0.137 g (1.2 mmol) of ammonium persulfate initiator and 7.5 μM of ferric tetrasulfonate phthalocyanine crosslinking agent in water and stir until fully dissolved to obtain solution B;

[0098] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane.

[0099] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0100] (4) Polyvinyl chloride: dioctyl sebacate in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%

[0101] Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: K + A sodium ion-selective membrane dispersion was prepared by dissolving the carrier in 350 μL of cyclohexanone.

[0102] (5) Add the potassium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0103] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M KCl solution.

[0104] (7) The electrode in step (6) is placed in KCl solution of different concentrations for testing to obtain the relationship between ion concentration and voltage, and to obtain the standard curve and linear equation to realize the monitoring of potassium ion concentration.

[0105] Example 10:

[0106] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; dissolve 0.137 g (1.2 mmol) of ammonium persulfate initiator and 7.5 μM of tetraaminoferrophthalocyanine crosslinking agent in water and stir until fully dissolved to obtain solution B;

[0107] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode respectively, and the two reacted on the electrode surface to obtain a polypyrrole nanofiber membrane.

[0108] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0109] (4) Polyvinyl chloride: dioctyl sebacate in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%

[0110] Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: K + A sodium ion-selective membrane dispersion was prepared by dissolving the carrier in 350 μL of cyclohexanone.

[0111] (5) Add the potassium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0112] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M KCl solution.

[0113] (7) The electrode in step (6) is placed in KCl solution of different concentrations for testing to obtain the relationship between ion concentration and voltage, and to obtain the standard curve and linear equation to realize the monitoring of potassium ion concentration.

[0114] Comparative example:

[0115] (1) Dissolve 42 μL (1.2 mmol) of pyrrole in 0.5 mL of isopropanol and stir until fully dissolved to obtain monomer solution A; dissolve 0.137 g (1.2 mmol) of ammonium persulfate initiator in 2 mL of water and stir until fully dissolved to obtain solution B;

[0116] (2) 25 μL of solution A and 50 μL of solution B were dropped onto the electrode, and the two reacted on the electrode surface to obtain a polypyrrole nanosphere film. Figure 2 a);

[0117] (3) After drying the electrode in step (2) in a 60°C oven, remove it;

[0118] (4) Polyvinyl chloride: dioctyl sebacate in a mass percentage ratio of 32.8%: 64.7%: 0.5%: 2%

[0119] Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate: K + A sodium ion-selective membrane dispersion was prepared by dissolving the carrier in 350 μL of cyclohexanone.

[0120] (5) Add the potassium ion selective membrane dispersion prepared in step (4) to the electrode obtained in step (3) and dry it to form a membrane;

[0121] (6) The prepared electrode was dried overnight in the dark and then pretreated in a 0.1M KCl solution.

[0122] (7) The electrodes in step (6) Figure 1 The figure above shows the results of testing the polypyrrole nanospheres in KCl solutions of different concentrations. The relationship between ion concentration and voltage was obtained, yielding a standard curve and a linear equation of y = 0.107 + 0.032x. The slope indicates that the WPIS of the obtained polypyrrole nanospheres is high in KCl solutions. + The sensitivity during detection was 32mV decade. –1 .

Claims

1. A method for fabricating a wearable potentiometric ion sensor based on a conductive polymer nanofiber membrane, characterized in that, Includes the following steps: (1) Dissolve the conductive polymer monomer in a solvent and stir until fully dissolved to obtain monomer solution A; dissolve the initiator and the 'quadruple' crosslinking agent in a solvent and stir until fully dissolved to obtain solution B; (2) Solution A and solution B are dropped onto the electrode respectively, and the two react on the electrode surface to obtain a conductive polymer nanofiber membrane; after drying in an oven, it is taken out. (3) Prepare an ion-selective membrane dispersion according to a certain ratio; (4) The ion-selective membrane dispersion prepared in step (3) is dropped onto the conductive polymer nanofiber membrane obtained in step (2) and dried to form a membrane; (5) Dry the prepared electrode in the dark overnight, and then pretreat it in the prepared 0.1M analyte solution; (6) Place the electrode from step (5) in solutions of ions to be tested with different standard concentrations to obtain the relationship between ion concentration and voltage, and obtain the standard curve and linear equation to achieve ion concentration monitoring; The conductive polymer monomer mentioned in step (1) is selected from pyrrole, aniline or thiophene, and the monomer has a mass fraction of 10% to 30% in solution A; The 'four-claw' type crosslinking agent is selected from copper tetrasulfonate phthalocyanine, zinc tetrasulfonate phthalocyanine, iron tetrasulfonate phthalocyanine, zinc tetracarboxylate phthalocyanine, or tetraaminoferrophthalocyanine, and its molar concentration in solution B is 7 μM~10 μM; In step (2), the volume ratio of the reaction between solution A and solution B is 1:

2.

2. The method according to claim 1, characterized in that, The initiator is ammonium persulfate (APS) or ferric chloride (FeCl3), with a mass fraction of 0.1-1% in solution B.

3. The method according to claim 1, characterized in that, In step (3), the ion-selective membrane dispersion formulation consists of a certain proportion of polyvinyl chloride, dioctyl sebacate, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and different ion carriers dissolved in cyclohexanone; the mass percentages of polyvinyl chloride, dioctyl sebacate, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and ion carriers are 32-35%: 62-65%: 0.4-0.6%: 1-3%.

4. The method according to claim 3, characterized in that, Different ion carriers are selected from K + carrier, NH4 + carrier, Na + carrier, Ca 2+ support, Cu 2+ carrier, Cl - carrier or Pb 2+ Carrier.

5. A wearable potentiometric ion sensor based on a conductive polymer nanofiber membrane prepared by the method according to any one of claims 1-4.

6. The wearable potential ion sensor based on a conductive polymer nanofiber membrane prepared according to any one of claims 1-4 can be directly worn on the skin to detect a variety of ions, and has high sensitivity and fast response time.

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