阅读说明：本技术 一种氯离子检测传感器 (Chloride ion detection sensor ) 是由 何镧 徐红梅 黄雷 周超 于 2021-09-09 设计创作，主要内容包括：本发明涉及一种氯离子检测传感器,包括绝缘基底和位于绝缘基底上的工作电极、参比电极、辅助电极以及各电极对应的电极焊点,工作电极位于参比电极与辅助电极之间；工作电极、参比电极和辅助电极分别通过电极导线与各自对应的电极焊点连接,各电极导线相互独立且其上覆盖有绝缘层；各电极焊点用于连接外部控制电路,以输出电极变化信号。本发明的氯离子检测传感器为全固态传感器,采用三电极体系,有利于减少无关物质的干扰,进一步提高传感器的稳定性和检测结果准确性；另外,具有体积小、反应速度快、灵敏度高、无需笨重的液态电极等特点,可以和电路板集成一体,与无线通信模块、控制电路相结合,可实现全自动无人值守氯离子的在线监测。(The invention relates to a chloride ion detection sensor, which comprises an insulating substrate, a working electrode, a reference electrode, an auxiliary electrode and electrode welding spots, wherein the working electrode, the reference electrode and the auxiliary electrode are positioned on the insulating substrate, and the electrode welding spots correspond to the electrodes; the working electrode, the reference electrode and the auxiliary electrode are respectively connected with the corresponding electrode welding points through electrode leads, and the electrode leads are mutually independent and are covered with insulating layers; each electrode welding spot is used for connecting an external control circuit so as to output an electrode change signal. The chloride ion detection sensor is an all-solid-state sensor, and a three-electrode system is adopted, so that the interference of irrelevant substances is reduced, and the stability and the accuracy of detection results of the sensor are further improved; in addition, the device has the characteristics of small volume, high reaction speed, high sensitivity, no need of bulky liquid electrodes and the like, can be integrated with a circuit board, is combined with a wireless communication module and a control circuit, and can realize the on-line monitoring of full-automatic unattended chlorine ions.)

1. A chloride ion detection sensor is characterized by comprising an insulating substrate, a working electrode, a reference electrode, an auxiliary electrode and electrode welding spots, wherein the working electrode, the reference electrode and the auxiliary electrode are positioned on the insulating substrate, and the electrode welding spots correspond to the electrodes;

the working electrode, the reference electrode and the auxiliary electrode are respectively connected with the corresponding electrode welding points through electrode leads, and the electrode leads are mutually independent and are covered with insulating layers;

each electrode welding spot is used for connecting an external control circuit so as to output an electrode change signal.

2. The chloride ion detecting sensor according to claim 1, wherein the working electrode includes a first conductive layer and a reaction layer sequentially stacked over an insulating substrate;

the first conducting layer is an interdigital electrode, and a conducting Cu film is evaporated on the insulating substrate by adopting an electron beam evaporation vacuum coating.

The reaction layer comprises a conductive nanofiber film layer, an Ag film layer and an AgCl film layer which are sequentially stacked on the first conductive layer.

3. The chloride ion detection sensor of claim 2, wherein the conductive nanofiber membrane layer is prepared by using polyvinylidene fluoride polymer as a spinning precursor, adding a conductive active material and a coupling agent, and performing electrostatic spinning.

4. The chloride detection sensor of claim 3, wherein the conductive active material comprises one or more of doped metal nanoparticles, fullerenes, graphene, carbon nanotubes.

5. The chloride ion detecting sensor according to claim 2, wherein the first conductive layer has a thickness of 50nm to 1 μm, the conductive nanofiber film layer has a film thickness of 100nm to 5 μm, the Ag film layer has a film thickness of 200nm to 5 μm, and the AgCl film layer has a film thickness of 500nm to 10 μm.

6. The chloride ion detection sensor of any one of claims 1-5, wherein the reference electrode comprises a second conductive layer, an Ag film layer, an AgCl film layer, and a hydrogel layer sequentially stacked on an insulating substrate.

7. The chloride ion detecting sensor according to claim 6, wherein the second conductive layer is a conductive Cu film evaporated on the insulating substrate by electron beam evaporation vacuum deposition, and the film thickness is 50nm to 1 μm;

the thickness of the Ag film layer is 200 nm-5 μm;

the film thickness of the AgCl thin film layer is 500 nm-10 mu m;

the thickness of the hydrogel layer is 0.5 to 1 μm.

8. The chloride detection sensor of claim 6, wherein the hydrogel layer comprises the following components: 2-hydroxyethyl methacrylate, polyvinylpyrrolidone, 2-dimethoxy-2-phenylacetophenone, ethylene glycol dimethacrylate and potassium chloride, wherein the weight ratio of the components is 5-15: 1: 0.2-0.6: 0.02-0.1: 1 to 4.

9. The chloride ion detecting sensor according to any one of claims 1 to 5, wherein the auxiliary electrode comprises a third conductive layer and a Pt thin film layer sequentially stacked on the insulating substrate;

the third conducting layer is a conducting Cu film evaporated on the insulating substrate by adopting an electron beam evaporation vacuum coating, and the thickness of the film is 50 nm-1 mu m;

the film thickness of the Pt thin film layer is 200 nm-10 mu m.

10. The chloride ion detection sensor of any one of claims 1-5, wherein the insulating substrate is a rigid silicon wafer or a flexible polyimide plastic substrate.

Technical Field

The invention belongs to the technical field of sensors, and particularly relates to a chloride ion detection sensor.

Background

Chloride ions are common inorganic anions in life and are commonly found in the fields of industry, agriculture, biomedical treatment and the like. In industry and agriculture, the concentration of chloride ions directly influences the corrosion resistance of metal pipelines and the growth of plants; in the biomedical field, the concentration of chloride ions in human blood, urine and sweat can be used to diagnose and monitor diseases such as cystic fibrosis, low-chloride metabolic alkalosis, etc.; in the food industry, the determination of the concentration of chloride ions has a certain guiding effect on the processing technology and quality of food. In addition, studies have shown that changes in the concentration of chloride ions in subsurface fluids are closely related to regional seismic activity. Therefore, the method has very important practical significance for quickly and accurately detecting the concentration of the chloride ions.

At present, the chloride ion detection method comprises a Morel method, a turbidimetry method, a spectrophotometry method, an ion chromatography method, a potentiometric titration method, an atomic absorption method, a polarography method, a flow injection analysis method and the like, and the method generally has the defects of complicated operation steps, high instrument price, difficult carrying, complex maintenance and the like.

Under the promotion of the technology of the internet of things, the sensor gradually develops towards miniaturization, integration and rapidness. Therefore, the development of a micro chloride ion detection sensor with fast reaction speed and high sensitivity is urgently needed in the field.

Disclosure of Invention

Based on the above-mentioned shortcomings and drawbacks of the prior art, it is an object of the present invention to at least solve one or more of the above-mentioned problems of the prior art, in other words, to provide a chloride ion detecting sensor that satisfies one or more of the above-mentioned needs.

In order to achieve the purpose, the invention adopts the following technical scheme:

a chloride ion detection sensor comprises an insulating substrate, a working electrode, a reference electrode, an auxiliary electrode and electrode welding spots, wherein the working electrode, the reference electrode and the auxiliary electrode are positioned on the insulating substrate, and the electrode welding spots correspond to the electrodes;

the working electrode, the reference electrode and the auxiliary electrode are respectively connected with the corresponding electrode welding points through electrode leads, and the electrode leads are mutually independent and are covered with insulating layers;

each electrode welding spot is used for connecting an external control circuit so as to output an electrode change signal.

Preferably, the working electrode comprises a first conductive layer and a reaction layer which are sequentially stacked on the insulating substrate;

the first conducting layer is an interdigital electrode, and a conducting Cu film is evaporated on the insulating substrate by adopting an electron beam evaporation vacuum coating.

The reaction layer comprises a conductive nanofiber film layer, an Ag film layer and an AgCl film layer which are sequentially stacked on the first conductive layer.

According to a preferable scheme, the conductive nanofiber membrane layer is prepared by taking polyvinylidene fluoride polymer as a spinning precursor, adding a conductive active material and a coupling agent, and performing electrostatic spinning.

Preferably, the conductive active material comprises one or more of doped metal nanoparticles, fullerene, graphene and carbon nanotubes.

Preferably, the first conductive layer has a thickness of 50nm to 1 μm, the conductive nanofiber film layer has a thickness of 100nm to 5 μm, the Ag film layer has a thickness of 200nm to 5 μm, and the AgCl film layer has a thickness of 500nm to 10 μm.

Preferably, the reference electrode comprises a second conductive layer, an Ag thin film layer, an AgCl thin film layer and a hydrogel layer which are sequentially stacked on the insulating substrate.

Preferably, the second conductive layer is a conductive Cu film evaporated on the insulating substrate by adopting an electron beam evaporation vacuum coating, and the thickness of the film is 50 nm-1 μm;

the thickness of the Ag film layer is 200 nm-5 μm;

the film thickness of the AgCl thin film layer is 500 nm-10 mu m;

the thickness of the hydrogel layer is 0.5 to 1 μm.

Preferably, the hydrogel layer comprises the following components: 2-hydroxyethyl methacrylate, polyvinylpyrrolidone, 2-dimethoxy-2-phenylacetophenone, ethylene glycol dimethacrylate and potassium chloride, wherein the weight ratio of the components is 5-15: 1: 0.2-0.6: 0.02-0.1: 1 to 4.

Preferably, the auxiliary electrode comprises a third conductive layer and a Pt thin film layer which are sequentially stacked on the insulating substrate;

the third conducting layer is a conducting Cu film evaporated on the insulating substrate by adopting an electron beam evaporation vacuum coating, and the thickness of the film is 50 nm-1 mu m;

the film thickness of the Pt thin film layer is 200 nm-10 mu m.

Preferably, the insulating substrate is a rigid silicon wafer or a flexible polyimide plastic substrate.

Compared with the prior art, the invention has the beneficial effects that:

(1) the chloride ion detection sensor is an all-solid-state sensor, and a three-electrode system is adopted, so that the interference of irrelevant substances is reduced, and the stability and the accuracy of detection results of the sensor are further improved; in addition, the device has the characteristics of small volume, high reaction speed, high sensitivity, no need of bulky liquid electrodes and the like, can be integrated with a circuit board, is combined with a wireless communication module and a control circuit, and can realize the on-line monitoring of full-automatic unattended chlorine ions.

(2) The working electrode is an Ag/AgCl chloride ion selective electrode, chloride ions and silver chloride in the solution to be detected form a dynamic balance, and when the concentration of the chloride ions in the solution changes, the potential of the Ag/AgCl electrode also changes; the potential of the reference electrode is stable and unchangeable in the solution to be measured, and the chloride ion concentration can be obtained by combining the energy Stokes equation; the auxiliary electrode and the working electrode form a loop to keep the current smooth and stable so as to ensure that all reactions occur on the working electrode and the measurement is more accurate.

(3) The chloride ion detection sensor adopts the flexible polyimide plastic substrate, so that the sensor is variable in form.

Drawings

FIG. 1 is a schematic view of the structure of a chloride ion detecting sensor according to embodiment 1 of the present invention;

FIG. 2 is a sectional view of a working electrode of example 1 of the present invention;

FIG. 3 is an exploded view of the structure of a working electrode of example 1 of the present invention;

FIG. 4 is a sectional view of a reference electrode in example 1 of the present invention;

FIG. 5 is a sectional view of an auxiliary electrode in example 1 of the present invention;

FIG. 6 is a schematic structural diagram of a mask according to an embodiment of the present invention;

fig. 7 is a schematic structural view of a chloride ion detecting sensor according to embodiment 2 of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention, the following description will explain the embodiments of the present invention with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

Example 1:

as shown in fig. 1 to 5, the chloride ion detecting sensor of the present embodiment includes an insulating substrate 7, and a reference electrode 1, a working electrode 2, an auxiliary electrode 3 and electrode pads 5 corresponding to the respective electrodes, which are located on the insulating substrate 7, wherein the working electrode 2 is located between the reference electrode 1 and the auxiliary electrode 3.

The insulating substrate 7 of the present embodiment is a rigid silicon wafer, i.e., an insulating silicon substrate.

The working electrode 2, the reference electrode 1 and the auxiliary electrode 3 are respectively connected with the corresponding electrode welding points 5 through electrode leads 4, the electrode leads are mutually independent, and insulating layers 6 are covered on the electrode leads; specifically, silicon rubber is applied to the surface of the electrode lead as an insulating layer 6 to protect the electrode lead.

Each electrode pad 5 is used for connecting an external control circuit to output an electrode change signal.

The working electrode 2 of the present embodiment includes a first conductive layer 2-1 and a reaction layer 2-2 sequentially stacked on an insulating substrate 7. Specifically, the first conducting layer 2-1 is an interdigital electrode and is prepared through a photoetching process, the interdigital electrode array pattern comprises a pair of sparse microelectrodes, each sparse microelectrode is provided with 3-10 fingers, and dozens of fingers on the two sparse microelectrodes are arranged in a crossed mode to form the interdigital electrode; the fingers are 3-8 mm long and 5 μm wide, the distance between every two adjacent fingers is 5 μm, and the interdigital strips with micro-distance can play a role in amplifying detection signals and further improve the detection sensitivity and precision of the sensor. Adopting electron beam evaporation vacuum coating to evaporate a conductive Cu film on an insulating substrate, wherein the thickness of the conductive Cu film is 50 nm-1 mu m;

the reaction layer 2-2 comprises a conductive nanofiber membrane layer 2-2A, Ag thin film layer 2-2B and an AgCl thin film layer 2-2C which are sequentially stacked on the first conductive layer 2-1. Specifically, the reaction layer is used for preparing a conductive nanofiber film on the first conductive layer by adopting an electrostatic spinning method, and then a metal Ag layer and an AgCl layer are sequentially deposited on the conductive nanofiber. The conductive nanofiber has the characteristics of high porosity, large specific surface area and uniform structure, and can improve the bearing capacity of a substance to be detected, thereby greatly increasing the electrochemical activity point position of the sensor, realizing the accelerated transmission and amplification of the nanofiber to an electric signal, improving the sensitivity of the sensor to chloride ion detection, shortening the detection time and improving the performance of the sensor.

The conductive nanofiber membrane layer 2-2A is prepared by taking polyvinylidene fluoride polymer as a spinning precursor, adding a conductive active material and a coupling agent, and performing electrostatic spinning.

The polyvinylidene fluoride polymer has excellent chemical stability such as corrosion resistance, high temperature resistance, oxidation resistance, ultraviolet ray resistance and the like, so that the chemical stability of the chloride ion sensor is improved, and the service life of the chloride ion sensor is prolonged.

The conductive active material comprises one or more of doped metal nanoparticles, fullerenes, graphene, carbon nanotubes. The conductive active material is added to improve the electron transfer performance of the material. The carbon nano tube doped in the nano fiber is taken as an example for illustration, the carbon nano tube has the advantages of excellent mechanical property, high mechanical strength, high conductivity, high electrochemical stability and the like, and the effective electric signal generated by the chloride ion reaction layer is improved. In addition, the carbon nano tube has good chemical stability, is beneficial to reducing signal fluctuation caused by complex components in the solution to be detected, reduces the interference of irrelevant substances, and improves the repeatability and stability of chloride ion detection.

The coupling agent may be one or more of aminopropyltriethoxysilane (KH550), glycidoxypropyltrimethoxysilane (KH560), methacryloxypropyltrimethoxysilane (KH570), vinyltriethoxysilane (A151), vinyltriethoxysilane (A171), mercaptopropyltrimethoxysilane (KH580, KH590), ethylenediamine propyltriethoxysilane (KH792), ethylenediamine propylmethyldimethoxysilane (KBM602), and the like. The addition of the coupling agent increases the binding force between the fiber film and the electrode, prevents the film from falling off, and prolongs the service life of the sensor.

The film thickness of the conductive nanofiber film layer is 100 nm-5 mu m, the film thickness of the Ag film layer is 200 nm-5 mu m, and the film thickness of the AgCl film layer is 500 nm-10 mu m.

The reference electrode 1 of the embodiment comprises a second conducting layer 1-1, an Ag thin film layer 1-2, an AgCl thin film layer 1-3 and a hydrogel layer 1-4 which are sequentially stacked on an insulating substrate 7, wherein the second conducting layer 1-1 is a conducting Cu film evaporated on the insulating substrate by adopting electron beam evaporation vacuum coating, and the film thickness is 50 nm-1 mu m; the thickness of the Ag film layer 1-2 is 200 nm-5 μm; the film thickness of the AgCl thin film layer 1-3 is 500 nm-10 mu m; the thickness of the hydrogel layer 1-4 is 0.5-1 μm. Specifically, the reference electrode is formed by depositing a conductive Cu film on an insulating substrate, then depositing an Ag film on the conductive Cu film, then depositing an AgCl film layer on the Ag film layer, and finally coating a hydrogel layer on the AgCl film layer.

Wherein the hydrogel layer comprises the following components: 2-hydroxyethyl methacrylate, polyvinylpyrrolidone, 2-dimethoxy-2-phenylacetophenone, ethylene glycol dimethacrylate and potassium chloride, wherein the weight ratio of each component is 10: 1: 0.4: 0.05: 2.75.

the auxiliary electrode 3 of the embodiment comprises a third conducting layer 3-1 and a Pt thin film layer 3-2 which are sequentially stacked on an insulating substrate 7, wherein the third conducting layer 3-1 is a conducting Cu film evaporated on the insulating substrate 7 by adopting an electron beam evaporation vacuum coating, and the film thickness is 50 nm-1 μm; the film thickness of the Pt thin film layer is 200 nm-10 mu m. Specifically, the auxiliary electrode is formed by depositing a conductive Cu film on an insulating substrate and then depositing a stable Pt film on the conductive Cu film.

The preparation process of the chloride ion detection sensor of the present embodiment is as follows:

(1) putting the insulating silicon substrate into an ultrasonic cleaning machine, cleaning the insulating silicon substrate with hydrogen peroxide, acetone and absolute ethyl alcohol in sequence, and drying. In vacuum equipment, the insulating silicon substrate is heated to 300 ℃ and the vacuum degree reaches 10^-5And Pa or above, evaporating a 50 nm-1 μm Cu film on the insulating silicon substrate, and photoetching the Cu film in a photoetching machine according to a designed mask (shown in figure 6) to obtain each conducting layer.

The interdigital electrode array pattern of the working electrode comprises a pair of sparse microelectrodes, each sparse microelectrode is provided with 3-10 fingers, and the 3-10 fingers on the two sparse microelectrodes are arranged in a crossed mode to form the interdigital electrode; the fingers are 3-8 mm long and 5 μm wide, and the distance between adjacent fingers is 5 μm.

(2) Preparing a layer of conductive nanofiber on the interdigital electrode by adopting an electrostatic spinning method: weighing 2g of polyvinylidene fluoride, dissolving the polyvinylidene fluoride in 25mL of acetone, stirring and dissolving, then adding 0.3g of carbon nano tube and 0.1g of aminopropyltriethoxysilane (KH550), and stirring to obtain a uniform and stable polyvinyl alcohol electrospinning precursor solution; injecting a proper amount of precursor solution into the injector, using a stainless steel needle head as a spinning nozzle, setting the electrostatic high-voltage direct current at 18 KV-25 KV, propelling the precursor solution at the speed of 1 mL/h-2.5 mL/h, and setting the spinning time to be 5-25 s. Under the action of an electric field, the polyvinyl alcohol electrospinning precursor solution forms a conductive composite fiber film with a high specific surface area of 100 nm-5 mu m and high porosity on the interdigital electrode.

(3) Putting the fiber film substrate into a vacuum coating chamber again for secondary electron beam evaporation vacuum coating, and respectively evaporating a layer of Ag film on the film fibers of the reference electrode and the working electrode in a plating way, wherein the thickness of the plating layer is 200 nm-5 mu m; then evaporating and plating an AgCl film layer, wherein the thickness of the plating layer is 500 nm-10 mu m; a layer of Pt film is vapor-plated on the auxiliary electrode, and the thickness of the plating layer is 200 nm-10 mu m; the coating mode is the same as that of evaporation of a Cu film.

(4) The outer surface of the reference electrode is coated with a layer of hydrogel. The hydrogel was prepared from 2-hydroxyethyl methacrylate: polyvinylpyrrolidone: 2, 2-dimethoxy-2-phenylacetophenone (DMPAP): ethylene glycol dimethacrylate and potassium chloride as 10: 1: 0.4: 0.05: 2.75 mass ratio for make-up coating.

(5) The silicon rubber is applied to the surface of the electrode lead as an insulating layer to prevent the electrode lead from being protected.

The working electrode of the chloride ion detection sensor is an Ag/AgCl chloride ion selective electrode, chloride ions and silver chloride in a solution to be detected form a dynamic balance, and when the concentration of the chloride ions in the solution changes, the potential of the Ag/AgCl electrode changes; the potential of the reference electrode is stable and unchangeable in the solution to be measured, and the chloride ion concentration can be obtained by combining the energy Stokes equation; the auxiliary electrode and the working electrode form a loop to keep the current smooth and stable so as to ensure that all reactions occur on the working electrode and the measurement is more accurate.

Example 2:

the chloride ion detection sensor of the present example is different from that of example 1 in that:

the insulating substrate 7 is replaced by a flexible polyimide plastic substrate, so that the form of the chloride ion detection sensor is changeable, as shown in fig. 7, the chloride ion detection sensor is of a curved surface structure, and the requirements of different detection applications are met;

other structures and preparation procedures can be referred to example 1.

Example 3:

the chloride ion detection sensor of the present example is different from that of example 1 in that:

the proportion of the hydrogel is different, and specifically, the dosage of 2-hydroxyethyl methacrylate, polyvinylpyrrolidone, 2-dimethoxy-2-phenylacetophenone, ethylene glycol dimethacrylate and potassium chloride can be within a corresponding range of 5-15: 1: 0.2-0.6: 0.02-0.1: 1-4, selecting according to actual application requirements;

other structures and preparation procedures can be referred to example 1.

The foregoing has outlined rather broadly the preferred embodiments and principles of the present invention and it will be appreciated that those skilled in the art may devise variations of the present invention that are within the spirit and scope of the appended claims.