WO2019227559A1

WO2019227559A1 - Solid conductive gel suitable for electrochemical system and preparation method therefor

Info

Publication number: WO2019227559A1
Application number: PCT/CN2018/093207
Authority: WO
Inventors: 董晓娅; 韩亚; 邱白晶; 管贤平
Original assignee: 江苏大学
Priority date: 2018-05-30
Filing date: 2018-06-28
Publication date: 2019-12-05
Also published as: CN109192355A; CN109192355B

Abstract

Provided by the present invention are a solid conductive gel suitable for an electrochemical system and a preparation method therefor. A new gelatin substrate is used to cure a liquid electrolyte of an electrochemical system by means of adding an active diluent and a room temperature curing agent, which improves bonding strength, adjusts curing time, and has strong bonding performance for both metal and non-metal, being weather resistant, being aging resistant, and being easy to operate, while the needs of electrochemical systems may be met. The present solid conductive gel has good toughness, high elongation, a simple structure, does not easily corrode a sensor substrate, and may be made into a gel substrate of different thicknesses, being convenient for transportation and carrying, while simultaneously being capable of avoiding cumbersome operations due to the quantitative transfer of a liquid electrolyte being required during on-site detection, being capable of replacing a liquid electrolyte of an electrochemical system and a solid conductive gel of an electrolytic cell thereof, and avoiding defects such as a liquid electrolyte being volatile, sealing being difficult, sensor substrate corrosion and so on. The preparation method of the present invention is simple, the raw materials are easy to obtain, the preparation conditions are not harsh, and extrusion properties are good, while having no special odor and not polluting the environment.

Description

Solid conductive gel suitable for electrochemical system and preparation method thereof

Technical field

The invention relates to a solid conductive gel suitable for an electrochemical system and a preparation method thereof, and particularly relates to a method for preparing a solid conductive gel that replaces an electrochemical system liquid electrolyte and an electrolytic cell thereof, and belongs to an electrochemical method test. Or analytical material technology.

technical background

Electrochemical detection technology is a detection technology that converts physical, chemical, and biological energy into electrical energy. By detecting changes in the current or potential signal of the output electrical energy, the analysis of the detected substance is achieved. The electrode is an electronic conductor or semiconductor that is in contact with the electrolyte solution or electrolyte. It works by the electrochemical reaction of the test object to generate an electrical signal that is proportional to the concentration of the test object. The electrochemical system uses the electrodes to realize the input or output of electrical energy. The liquid electrolyte and its electrolytic cell are the places where the electrode reactions are performed. Chinese patent CN 102183678 A discloses a multifunctional electrolytic cell for a scanning electrochemical microscope. The three-electrode system, four-electrode system, and its complex system can be completed through different structures of the lower cover. PCT patent CN103155067A discloses an electrolyte system and an electrolytic cell, and relates to an electrolyte system and an electrolytic cell containing the electrolyte system. No. 7,297,289 discloses an electrolyte system, which describes an ionic liquid as an electrolyte.

So far, liquid electrolytes and their electrolytic cells are still a necessary place for electrode reactions. During the electrochemical detection experiment, the use of this electrolytic cell has the following deficiencies or disadvantages: (1) the liquid electrolyte or electrolytic cell is volatile and difficult to seal. (2) The structure of the liquid electrolyte or electrolytic cell is relatively complicated, the operation is complicated, and the sensor substrate is easily corroded. (3) It can only be used in the laboratory and cannot be used for field tests.

Solid conductive gel is a kind of adhesive with certain conductive properties after curing or drying. It usually uses the matrix resin and conductive fillers as the main components. The matrix particles are used to bond the conductive particles together to form conductivity. Via to achieve conductive connection of the adhered material. Since the matrix resin of the conductive adhesive is an adhesive, a suitable curing temperature can be selected for bonding. At the same time, due to the miniaturization, miniaturization of electronic components and the rapid development of high density and high integration of printed electrodes, conductive Glues can be made into pastes for high linear resolution. Compared with the currently widely used liquid electrolytes and their electrolytic cells, it avoids defects such as volatile liquid electrolytes, difficult sealing, and corrosion of the sensor substrate. It has many advantages such as stability, applicability, and long service life. An important trend in the development of rubber material technology.

In terms of technology, there are few reports about the research of solid conductive gel to replace the liquid electrolyte of the electrode of the electrochemical system and its electrolytic cell at home and abroad. Conventional solid conductive gel preparation methods mainly adopt spraying, printing, rubber roller, spin coating and other methods to attach or embed conductive materials in the substrate. Chinese patent CN 102087884A discloses a transparent conductive film with silver nano-semi-buried in the surface layer of an organic polymer. Chinese patent CN 102087886A discloses a transparent conductive film composed of a silver nanowire-based substrate, an adhesive layer and a conductive layer. Chinese Patent No. CN 102183678A discloses a conductive adhesive, which provides a conductive adhesive having the function of conducting, bonding and fixing. The above solid conductive gel is mainly characterized by silver nanometer conductive filler, relatively expensive materials, and low adhesion. In addition, the process of preparing conductive adhesive is complicated and difficult to operate. The conductive and thermal performance cannot be guaranteed, and the conductive stability and repeatability need to be improved.

Summary of the Invention

The invention provides a solid conductive gel suitable for an electrochemical system and a preparation method thereof. A new gelatin matrix is used, and the liquid electrolyte of the electrochemical system is cured by adding a reactive diluent and a room temperature curing agent to obtain a solid conductive gel suitable for the electrochemical system. The solid conductive gel improves the bonding strength and adjusts Curing time, strong adhesion to metal and non-metal, weather resistance, aging resistance, easy operation, can meet the needs of the electrochemical system. The solid conductive gel of the invention has good toughness, high elongation, simple structure, and is not easy to corrode the sensor substrate. It can be made into gel substrates of different thicknesses, which is convenient for transportation and carrying, and can avoid the quantitative transfer of liquid electrolytes during the on-site detection process. The tedious operation can replace the liquid electrolyte of the electrochemical system and the solid conductive gel of the electrolytic cell, and avoid defects such as volatile liquid electrolyte, difficult sealing, and corrosion of the sensor substrate. The method for preparing a solid conductive gel suitable for an electrochemical system according to the present invention is as follows: first, weigh 2.5 g of gelatin and add 97.5 mL of BR buffer solution with a pH of 7 to ultrasonically disperse for 30 min; second, add 0.05 g to the mixture at normal temperature Reactive diluent and 0.25g of modified amine triethylenetetramine were magnetically stirred to make them mix well; again, 0.2g of defoamer was added and stirred uniformly, and after vacuum defoaming treatment, a uniform, transparent gel-like liquid was prepared. The gelatinous liquid is coated in a tetrafluoroethylene mold and left to level at room temperature for 10 minutes. Finally, the gelatinous liquid in the mold is placed in a blast drying oven and heated to 60 ° C to 70 ° C for 30 to 40 minutes; After taking out the heat, it was cured at room temperature for 40 min, and then a transparent solid conductive gel was obtained by demolding. The purpose of the present invention is to provide a solid conductive gel suitable for an electrochemical system and a preparation method thereof. The preparation method is simple, raw materials are easily available, the preparation conditions are not harsh, the extrusion properties are good, there is no special odor, and the environment is not polluted.

Beneficial effect

The invention provides a solid conductive gel suitable for an electrochemical system to solidify a liquid electrolyte of an electrochemical system, and replaces the solid conductive gel of an electrochemical system liquid electrolyte and an electrolytic cell thereof. The solid conductive gel adopts a new gelatin matrix. It has the advantages of good electrical conductivity, high volume conductivity, good toughness, high elongation, controllable thickness, and simple preparation method. It can improve the bonding strength, and has strong adhesion properties to both metal and non-metal, which can be avoided. The liquid electrolyte is volatile, difficult to seal, corrosive to the sensor substrate, and the tedious operation of quantitatively transferring the liquid electrolyte during the on-site detection process. It has a simple structure, weather resistance, and aging resistance. It is not easy to corrode the sensor substrate and is easy to transport and carry. In addition, the solid conductive gel of the present invention can also adjust the curing time of the solid conductive gel, is easy to operate, and can meet the requirements of the electrochemical system. Its preparation raw materials are easy to obtain, the preparation method is simple, the conditions are not harsh, and the extrusion properties are good. Special odor, environmentally friendly material.

In order to solve the above technical problems and achieve the above objectives, the technical solution of the present invention is as follows:

The invention provides a solid conductive gel suitable for an electrochemical system and a preparation method thereof, which solidifies a liquid electrolyte of an electrochemical system and replaces the liquid electrolyte of an electrochemical system and an electrolytic cell thereof. The constituent raw materials of the solid conductive gel are: component A is a polymer matrix, component B is a B-R buffer solution, component C is a modified triethylenetetramine and a reactive diluent, and component D is a defoamer. The method for preparing a BR buffer solution is: Measure 52.5mL of 0.2M NaOH alkali solution, add it to a beaker containing 100mL of 0.04M triacid mixed solution (phosphoric acid, acetic acid, and boric acid), and perform ultrasonic dispersion; Dispersion was carried out for 30 minutes in a medium, and a BR buffer solution having a pH of 7 was prepared after the ultrasonic dispersion. The method for preparing a solid conductive gel suitable for an electrochemical system is: Weigh 2.5 g of gelatin, add 97.5 mL of BR buffer solution with a pH of 7 and ultrasonically disperse for 30 min; add 0.05 g of active diluent and 0.25 to the mixture at normal temperature. g Modified amine triethylenetetramine is magnetically stirred to make it mix well; 0.2g of defoamer is added and stirred uniformly, and after vacuum defoaming treatment, a uniform, transparent gelatinous liquid is prepared; the gelatinous liquid is coated on Place it in a tetrafluoroethylene mold for 10 minutes at room temperature to level it. Put the gelatinous liquid in the mold into a blast drying oven and heat it to 60 ℃ ～ 70 ℃ for 30 ～ 40min; take it out after heat preservation, and cure it at room temperature for 40min. After that, the transparent solid conductive gel is obtained by demolding.

Preferably, in the process of preparing the BR buffer solution, the alkaline solution may be selected from NaOH or KOH, etc., the concentration of the alkaline solution may be 0.1 to 2 mol / L, and the mixed solution of the alkaline solution and triacid (phosphoric acid, acetic acid) , Boric acid) can be (0-100mL): 100mL, where the alkali solution and triacid mixed solution are calculated by volume. The pH value of the B-R buffer solution can be adjusted with an acid solution and an alkali solution, and the adjustment range is from 0 to 12. The alkali solution used to adjust the pH value of the B-R buffer solution may be selected from NaOH or KOH; and the acid solution is selected from a triacid mixed solution (phosphoric acid, acetic acid, boric acid).

Preferably, in preparing a solid conductive gel suitable for an electrochemical system and a method for preparing the same, the gelatin is a colorless, odorless, non-volatile, transparent, hard polymer water-soluble protein, and has better Transparency and resistance to yellowing. The gelatin solution can form a gel that has a certain hardness and cannot flow. When the gelatin gel is stimulated by the environment, its performance will respond accordingly, that is, when the solution composition, pH value, ionic strength changes, temperature, light intensity, electric field and other stimulation signals change, or it is stimulated by specific chemicals When the gel is mutated, the phase transition behavior appears. The gelatin is also an effective protective colloid, which can prevent the aggregation of crystals or ions, is used to stabilize a heterogeneous suspension, and acts as an emulsifier in an oil-in-water dispersion medicament. Good choices of gelatin include Shanghai Aladdin Biochemical Technology Co., Ltd. G108395 and Sinopharm Chemical Reagent 10010326.

Preferably, in the method for preparing a solid conductive gel suitable for an electrochemical system, the solid conductive gel system requires that the curing agent has a short curing time, a low curing temperature, and good connection strength, toughness and weather resistance after curing. And other advantages, commonly used curing agents are aliphatic amines, cycloaliphatic amines, polyphthalamides, and aromatic amines, and their properties are shown in Table 1. By comparison, the present invention selects aliphatic modified amine triethylenetetramine as a room temperature curing agent. It is characterized by medium and low temperature curing, fast curing speed and easy use.

Table 1

BRIEF DESCRIPTION OF THE DRAWINGS

Table 1 is a comparison table of curing agent properties.

Table 2 is the cyclic voltammetry experiment parameters.

Table 3 is a dosage table of each component of the five solid conductive gel samples.

Table 4 Physical properties of five solid conductive gel samples corresponding to different amounts of gelatin and B-R buffer.

Figure 1 is a conventional electrochemical system.

Figure 2 is an electrochemical system based on a solid conductive gel

Figure 3 is a photograph of a solid conductive gel.

FIG. 4 is a comparison of the cyclic voltammetry curve (CV) of the screen-printed three electrodes in the electrolyte solution and the case with the solid conductive gel attached.

FIG. 5 is a cyclic voltammetry curve (CV) of a screen-printed electrode with a solid conductive gel under conditions where the concentration of cevaine is A (0.5 mM), B (1.0 mM), and C (1.5 mM).

Figure 6 is a texture analyzer measurement curve of five solid conductive gel samples corresponding to different gelatin and B-R buffer volumes.

In the figure: 1-electrochemical three-electrode sensor; 2-electrolyte solution; 3-electrolytic cell; 4-solid conductive gel.

Detailed ways

The principle and process of the present invention will be further understood and described with reference to the accompanying drawings.

Example one

The constituent materials and weight of the solid conductive gel in this embodiment are: 2.5 g of gelatin, 97.5 mL of B-R buffer solution, 0.25 g of modified amine triethylene tetramine curing agent, 0.05 g of active diluent, and 0.2 g of antifoaming agent.

1) Prepare a BR buffer solution: (a), measure 52.5mL of 0.2M NaOH alkali solution and add it to a beaker containing 100mL of 0.04M triacid mixed solution (phosphoric acid, acetic acid, boric acid), and perform ultrasonic dispersion; (b), The sample was placed in a sonicator and ultrasonically dispersed for 30 min; (c) After the ultrasonic dispersion, a BR buffer solution having a pH of 7 was prepared.

In step (a) of preparing a BR buffer solution, the alkaline solution may be selected from NaOH or KOH, etc., the concentration of the alkaline solution may be 0.1 to 2 mol / L, and the mixed solution of the alkaline solution and triacid (phosphoric acid, The proportion of acetic acid and boric acid) can be (0-100 mL): 100 mL, where the alkali solution and the triacid mixed solution are calculated by volume. The pH value of the B-R buffer solution can be adjusted with an acid solution and an alkali solution, and the adjustment range is from 0 to 12. The alkaline solution for adjusting the pH value of the B-R buffer solution may be selected from NaOH or KOH; and the acid solution is selected from a triacid mixed solution (phosphoric acid, acetic acid, boric acid).

2) Preparation of a solid conductive gel for an electrochemical system: (a) Weigh 2.5 g of gelatin, add 97.5 mL of BR buffer solution with a pH of 7 to ultrasonically disperse for 30 min; (b) magnetically stir the solution at room temperature, And under stirring state, add 0.05g of active diluent and 0.25g of modified amine triethylenetetramine room temperature curing agent to the mixed solution; (c), add 0.2g defoaming agent under stirring state, and mix the mixed solution After homogenization, a homogeneous, transparent gelatinous liquid is prepared after the vacuum defoaming treatment; (d), the gelatinous liquid is coated in a tetrafluoroethylene mold and left to level at room temperature for 10 minutes; (d), Put the gelatinous liquid in the mold into a blast drying oven, heat it to 60 ℃ ～ 70 ℃ and keep it for 30 ～ 40min; (f), take it out after heat preservation, and cure it at room temperature for 40min, then release it to obtain a transparent solid. Conductive gel.

In step (a) of preparing a solid conductive gel of an electrochemical system, the gelatin is a colorless, odorless, non-volatile, transparent and hard polymer water-soluble protein, which has good transparency and yellow resistance. change. The gelatin solution can form a gel that has a certain hardness and cannot flow. When the gelatin gel is stimulated by the environment, it will respond accordingly, that is, when the composition, pH value, ionic strength of the solution changes, temperature, light intensity, electric field and other stimulation signals change, or when it is stimulated by specific chemicals, The gel will mutate and show phase transition behavior. The gelatin is also an effective protective colloid, which can prevent the aggregation of crystals or ions, is used to stabilize a heterogeneous suspension, and acts as an emulsifier in an oil-in-water dispersion medicament. The gelatin selection includes Shanghai Aladdin Biochemical Technology Co., Ltd. G108395.

In step (b) of preparing the solid conductive gel of the electrochemical system, the solid conductive gel system requires that the curing agent has the advantages of short curing time, low curing temperature, and good connection strength, toughness, and weather resistance after curing. The curing agents include aliphatic amines, alicyclic amines, polyphthalamides, and aromatic amines, and the properties are compared in Table 1. By comparison, the present invention selects aliphatic modified amine triethylenetetramine as a room temperature curing agent. It is characterized by medium and low temperature curing, fast curing speed and easy use.

Example two

During the experimental test, the indoor temperature is 15-25 ° C, and the temperature fluctuation is not greater than ± 2 ° C / h. The relative humidity is 20% ～ 80%, the pressure is standard atmospheric pressure, and there is no strong mechanical vibration and electromagnetic interference in the laboratory.

Under the best experimental conditions, first connect the screen-printed three-electrode (Shanghai Yida Technology Co., Ltd.) to a special interface, and then use the special interface to connect with the CHI440A electrochemical workstation (Shanghai Chenhua Instrument Equipment Co., Ltd.). Screen-printed three electrodes were tested in a non-circulating vessel environment. Open the CHI440A electrochemical workstation and host computer, and set each parameter range on the host computer test software.

The screen-printed three electrodes were selected to test the cyclic voltammetry experiment in an electrolyte solution and with a solid conductive gel attached. The parameters set in the cyclic voltammetry experiment are shown in Table 2. The initial potential starts from -400mV, the highest potential is 600mV, the lowest is -400mV, the final potential is -400mV, and the scanning speed is 50mV / s. For the convenience of comparison, the two data are presented in an overlapping display mode. As shown in Figure 4, curve A is the cyclic voltammetry curve of the screen-printed three electrodes with a solid conductive gel attached, and curve B is the screen. Print the cyclic voltammetry curve of the three electrodes in the electrolyte solution. Buffering conditions: 40 mM electrolyte buffer, pH 7. Scanning speed: 50mV / s. By analyzing the CV curve information, it can be seen that the test results of the solid conductive gel are quite close to the test results of the electrolyte solution.

Table 2

Example three

Under the best experimental conditions, first connect the screen-printed three-electrode (Shanghai Yida Technology Co., Ltd.) to a special interface, and then use the special interface to connect with the CHI440A electrochemical workstation (Shanghai Chenhua Instrument Equipment Co., Ltd.) Screen-printed three electrodes were tested in a non-circulating vessel environment. Open the CHI440A electrochemical workstation and host computer, and set each parameter range on the host computer test software.

Using the same screen-printed three electrodes (Shanghai Yida Technology Co., Ltd.), cyclic voltammetry was used to test three different concentrations of 0.5 mM, 1.0 mM, and 1.5 mM Siwein solutions. The parameters are shown in Table 2. The initial potential starts from -400mV, the highest potential is 600mV, the lowest is -400mV, the final potential is -400mV, and the scanning speed is 50mV / s. Cyclic voltammetry experimental results are shown in FIG. 5. For the convenience of comparison, the three groups of data are presented in an overlapping display mode. By analyzing the CV curve information, it can be seen that the oxidation peak will change with the increase of the concentration of the Siwein solution. In the case of solid conductive gel, the screen-printed three-electrode can be applied to the measurement of the actual sample solution concentration.

Example 4

The screen-printed three-electrode used is a model 110-screen-printed three-electrode (Shanghai Yida Technology Co., Ltd.), the electrode surface area is 50.7mm ² , the working electrode is a carbon electrode, the reference electrode is Ag / AgCl, and the counter electrode is Carbon electrode. The detection instrument is an electrochemical workstation CHI440A (Shanghai Chenhua Instrument Equipment Co., Ltd.). Siwein powder 98% (purchased from Aladdin Co. (Shanghai, China))

Under the best experimental conditions, refer to the Texture Analyzer Analyzer X-T21 texture instrument instruction manual and select the gel type sample measurement conditions: probe mold is P / 2N; probe radius is 1m; measurement mode is TPA; measurement option is Return The test speed was 1.0mm / s; the initial speed was 1.0mm / s; the penetration distance was 20mm; the lift was 1.0mm / s; the temperature was 20 ° C.

In the mixed solution, adjust the amount of gelatin and BR buffer solution, and prepare five solid conductive gel samples numbered 1, 2, 3, 4, and 5 according to the method in Table 3 (other conditions are the same as the standard conditions). Figure 6 shows the adjustment of gelatin. The effect of the addition amount of BR and BR buffer solution on the properties of solid conductive gel. Table 4 shows the physical properties of five solid conductive gel samples corresponding to different amounts of gelatin and BR buffer solution.

table 3

Table 4

Claims

A solid conductive gel suitable for an electrochemical system, characterized in that the constituent raw materials of the solid conductive gel are: component A is a polymer matrix, component B is a BR buffer solution, and component C is triethylene tetrafluoride Amine and reactive diluent, component D is a defoamer; it solidifies the liquid electrolyte of the electrochemical system and replaces the liquid electrolyte of the electrochemical system and its electrolytic cell.
The solid conductive gel suitable for an electrochemical system according to claim 1, characterized in that the polymer matrix is gelatin; the gelatin is a mixture of high molecular weight water-soluble proteins, and is odorless, It is odorless, transparent, and resistant to yellowing. The gelatin selected is Shanghai Aladdin Biochemical Technology Co., Ltd. G108395.
The solid conductive gel suitable for an electrochemical system according to claim 1, wherein the preparation method of the B-R buffer solution is as follows:

a) Measure 52.5mL 0.2M NaOH alkali solution into 100mL 0.04M triacid mixed solution (phosphoric acid, acetic acid, boric acid), and perform ultrasonic dispersion;

b) Put the sample in the ultrasonic instrument and ultrasonically disperse for 30min;

c) After the ultrasonic dispersion, a B-R buffer solution with a pH of 7 is prepared.
The method for preparing a solid conductive gel suitable for an electrochemical system according to claim 1, wherein the method for preparing the solid conductive gel is as follows:

a) Weigh 2.5g of gelatin and add it to 97.5mL B-R buffer solution with pH 7 for ultrasonic dispersion for 30min;

b) Add 0.05g of active diluent and 0.25g of modified amine triethylenetetramine to the mixture at room temperature to magnetically stir to make the mixture uniform;

c) adding 0.2g of antifoaming agent to the above-mentioned uniformly mixed liquid, and stirring to make the mixture uniform;

d) After the vacuum defoaming treatment, a uniform and transparent gelatinous liquid is obtained;

e) The above gelatinous solution is coated in a tetrafluoroethylene mold and left to level for 10 minutes at room temperature;

f) Put the gelatinous liquid in the mold into a blast drying oven, and heat it to 60 ℃ ～ 70 ℃ for 30 ～ 40min;

g) Take it out after heat preservation, and after curing for 40 minutes at normal temperature, release the mold to obtain a transparent solid conductive gel.