Hydrogen bond heterojunction polymer, preparation method and nitrogen dioxide resistive sensor

Abstract

The invention relates to a hydrogen bond heterojunction polymer, a preparation method and a nitrogen dioxide resistive sensor, and belongs to the technical field of organic semiconductor devices. The polymer is of a heterojunction structure formed by a squaric acid amide polymer and a metal coordination polymer through hydrogen bond interaction. When the polymer is in contact with nitrogen dioxide molecules, more charge transfer can be generated, and the sensitivity of the hydrogen bond heterojunction polymer is improved. The polymer is used in a nitrogen dioxide resistive sensor, the device detection limit is low, and ppb-level nitrogen dioxide detection can be realized. The preparation method of the polymer is simple to operate and easy to industrialize.

Description

Technical Field

[0001] The invention relates to a hydrogen bond heterojunction polymer, a preparation method and a nitrogen dioxide resistive sensor, and belongs to the technical field of organic semiconductor devices. Background Art

[0002] Nitrogen oxides are one of the three major components of haze in the air, including nitrogen pentoxide, nitrogen dioxide (NO2), and nitric oxide. Among them, nitrogen oxide pollutants in the atmosphere mainly refer to NO and NO2, collectively referred to as NO x , its sources can be divided into natural sources and anthropogenic sources. Natural sources are mainly produced by nitrogen-fixing bacteria and lightning; anthropogenic sources can be divided into fixed nitrogen oxide sources produced by enterprises through the combustion of fossil energy and mobile sources of nitrogen oxides emitted by vehicles at low altitudes, which have the characteristics of high pollution intensity, wide pollution range, and concentrated emission area. NO2 will form acid rain with SO2 and dust, leading to ozone hole. NO2 contained in the ash formed by photochemical smog will also participate in PM 2.5 The formation of NO2. As a colorless gas with a pungent odor, NO2 is harmful to the human body even in low concentrations. NO2 can cause mild eye and upper respiratory tract irritation symptoms such as throat discomfort and dry cough at the initial stage of inhalation. When the concentration exceeds 1ppm, it will pose a threat to the human respiratory system. Long-term exposure to ppm-level NO2 environment can cause respiratory diseases such as bronchitis, dyspnea, emphysema and even heart disease. Delayed obstructive bronchiolitis may occur about two weeks after emphysema subsides. In addition, NO2 is also a major environmental pollutant, which can cause acid rain and photochemical smog, trigger acidification of surface water, lead to eutrophication of water bodies (due to the rich nutrients such as nitrogen and phosphorus in the water, the massive reproduction of algae leads to hypoxia), and increase the content of toxins in the water that are harmful to fish and other aquatic life.

[0003] Organic chemical resistors have attracted much attention due to their designable structure and low cost. High sensitivity, specific selectivity, reversible reaction / recovery and other robustness indicators are the key to evaluating sensory performance. Although square acid amide polymers can achieve the detection of nitrogen dioxide as low as 60 ppb (parts per billion), their sensitivity and detection limit still need to be further improved. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a hydrogen bond heterojunction polymer, a preparation method and a nitrogen dioxide resistive sensor.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] A hydrogen bond heterojunction polymer, wherein the polymer is formed by a squarylamide polymer and a metal coordination polymer through hydrogen bond interaction to form a heterojunction structure, and the structural formula of the polymer is:

[0007] Wherein, n is a positive integer.

[0008] Preferably, the molar ratio of the squarylamide polymer to the metal coordination polymer is 0.5 to 2:1.

[0009] A method for preparing the hydrogen-bonded heterojunction polymer of the present invention comprises the following steps:

[0010] (1) Under a protective gas (nitrogen or inert gas) atmosphere, p-phenylenediamine and diethyl squarate are heated to react in a reaction solvent to obtain a crude product, which is purified to obtain a squarylamide polymer powder;

[0011] (2) Add concentrated aqueous ammonia to an aqueous solution of 1,2,4,5-tetraaminobenzene hydrochloride at 0-5°C until the reaction system is neutral, then add an aqueous solution of nickel chloride to react to obtain a metal coordination polymer solution; add squarylamide polymer powder to the metal coordination polymer solution, react, filter, and vacuum dry to obtain a hydrogen bond heterojunction polymer.

[0012] Preferably, in step (1), the molar ratio of p-phenylenediamine, diethyl squarate and reaction solvent is 1:1:100-300.

[0013] Preferably, in step (1), the reaction solvent is a mixed solution of toluene and chloroform in a volume ratio of 1:1, or a mixed solution of toluene and acetonitrile in a volume ratio of 1:1.

[0014] Preferably, in step (1), the reaction temperature is 90-130° C. and the reaction time is 9-16 h.

[0015] Preferably, in step (1), during purification, the crude product is added to an extraction solvent, heated and stirred at 70 to 90° C. for 24 to 48 hours under a protective gas (nitrogen or inert gas) atmosphere, naturally cooled, filtered, and vacuum dried at 60 to 90° C. to obtain a squarylamide polymer powder.

[0016] Preferably, in step (2), the concentrations of the aqueous solution of 1,2,4,5-tetraaminobenzene hydrochloride and the aqueous solution of nickel chloride are 0.01 to 1 mol / L, respectively.

[0017] Preferably, in step (2), the molar ratio of 1,2,4,5-tetraaminobenzene hydrochloride, nickel chloride and squarylamide polymer is 1:1:0.5-2.

[0018] Preferably, in step (2), the reaction time is 9 to 16 hours.

[0019] Preferably, in step (2), the vacuum drying temperature is 60 to 90°C.

[0020] A nitrogen dioxide resistive sensor, wherein the interdigital electrodes of the sensor are coated with a hydrogen bond heterojunction polymer according to the present invention.

[0021] Preferably, the sensor is prepared by the following method, the method steps comprising:

[0022] (1) ultrasonically dispersing the hydrogen-bonded heterojunction polymer in a solvent to obtain a dispersion; the mass ratio of the hydrogen-bonded heterojunction polymer to the solvent is 1:400-600; and the ultrasonic time is 2-10 minutes;

[0023] (2) The dispersion is brushed onto a clean interdigital electrode, and after the solvent is naturally evaporated and removed, it is dried to obtain a nitrogen dioxide resistive sensor.

[0024] Preferably, the solvent is one or more of ethanol, chloroform and acetone, more preferably chloroform.

[0025] Preferably, the brushing is completed with a brush pen, the brushing times are 5 to 10 times, and the surface is brushed again after each brushing. The interdigital electrode includes an aluminum oxide substrate and a silver-palladium alloy electrode, the interdigital width is 50 to 100 μm, the interdigital spacing is 200 to 300 μm, the aluminum oxide substrate thickness is 1 to 2 mm, and the silver-palladium alloy electrode thickness is 100 to 200 nm. The drying temperature is 50 to 80°C, and the drying time is 0.5 to 2 hours.

[0026] Beneficial Effects

[0027] The invention provides a hydrogen bond heterojunction polymer, wherein a squarylamide polymer and a metal coordination polymer form a heterojunction structure through hydrogen bond interaction, and the polymer can generate more charge transfer when in contact with nitrogen dioxide molecules, thereby increasing the sensitivity of the hydrogen bond heterojunction polymer. The polymer is used in a nitrogen dioxide resistive sensor, and the device has a low detection limit, and can detect nitrogen dioxide at the ppb level. The polymer preparation method is simple to operate and easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the infrared spectrum result of the hydrogen bond heterojunction polymer described in Example 1.

[0029] Figure 2 This is the response test result of the sensor device in Example 1.

[0030] Figure 3 The performance comparison results of the sensor device in Example 1 are shown in FIG. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with specific embodiments.

[0032] Example 1

[0033] Synthesis of Hydrogen Bonded Heterojunction Polymers:

[0034] Weigh p-phenylenediamine (0.55g, 5mmol), diethyl squarate (0.85g, 5mmol), toluene (46.1g, 0.5mol) and acetonitrile (20.5g, 0.5mol) and place them in a single-mouth pressure-resistant bottle. After loading the reflux device, replace the air in the reaction system with nitrogen four times. Then heat it to 125℃, turn on the stirring device, and reflux for 12h. After the reaction is complete, wait for the temperature to drop to room temperature, filter the product and dry it in a vacuum oven at 70℃ to obtain an orange powder crude product. Then use a Soxhlet extractor to purify the obtained crude product, and the selected extractant is tetrahydrofuran. After the crude product is loaded into the Soxhlet extractor, replace the air in the reaction system with nitrogen four times. Heat it to 65℃, turn on the stirring device, reflux for 36h, wait for the temperature to drop to room temperature, filter the product and dry it in a vacuum oven at 65℃ to obtain 0.76g of orange powder of squaramide polymer.

[0035] Weigh 1,2,4,5-tetraaminobenzene hydrochloride (0.28 g, 1 mmol), nickel chloride (0.13 g, 1 mmol), and squaryl amide polymer (0.19 g, 1 mmol); dissolve 1,2,4,5-tetraaminobenzene hydrochloride and in 10 ml of pure water respectively, and place in a low-temperature reaction tank to cool to 0°C, slowly drop concentrated ammonia water (12 M / L) into the 1,2,4,5-tetraaminobenzene hydrochloride solution until the reaction system is neutral, then slowly add nickel chloride solution and react at room temperature for 10 hours to obtain a metal coordination polymer solution; finally, add the squaryl amide polymer and continue stirring the reaction at room temperature for 12 hours. After the reaction is completed, filter and dry in vacuo at 70°C to obtain a hydrogen-bonded heterojunction polymer powder.

[0036] The infrared spectrum of the hydrogen bond heterojunction polymer is as follows Figure 1 As shown, the results show that compared with the squarylamide polymer and the coordination polymer, some functional groups of the hydrogen-bonded heterojunction polymer undergo red-shift or blue-shift, proving the existence of hydrogen-bonding interactions.

[0037] Preparation of the sensor:

[0038] (1) ultrasonically clean the interdigital electrodes using 10 ml of water, ethanol, and acetone in sequence, and dry them for later use;

[0039] (2) adding 4 mg of hydrogen-bonded heterojunction polymer to 2 g of chloroform by ultrasonic dispersion for 5 minutes to obtain a dispersion containing the hydrogen-bonded heterojunction polymer;

[0040] (3) The dispersion was brushed on the interdigital electrodes for 8 times, and the surface was dried before brushing again after each brushing. After brushing, the surface was left at room temperature, and after evaporation, it was placed in an oven at 60°C for 1 hour to obtain a nitrogen dioxide resistive sensor based on hydrogen bond heterojunction polymer with a film thickness of 300 μm.

[0041] The current response of the sensor under different concentrations of nitrogen dioxide is measured:

[0042] First, the device was placed in pure nitrogen conditions. After the current stabilized, the device was placed in nitrogen dioxide atmospheres of different concentrations. After the current stabilized, the device was placed in pure nitrogen conditions again and the above cycle was repeated. The results are as follows: Figure 2 and Figure 3 As shown in the figure, it can be seen that the sensor based on hydrogen bond heterojunction polymer can have good response and recovery performance to nitrogen dioxide as low as 10ppb, and its response value is larger than that of square acid amide polymer and metal coordination polymer.

[0043] Example 2

[0044] Synthesis of Hydrogen Bonded Heterojunction Polymers:

[0045] Weigh p-phenylenediamine (0.11g, 1mmol), diethyl squarate (0.17g, 1mmol), toluene (46.1g, 0.5mol) and acetonitrile (20.5g, 0.5mol) and place them in a single-mouth pressure-resistant bottle. After loading the reflux device, replace the air in the reaction system with nitrogen four times. Then heat it to 125℃, turn on the stirring device, and reflux for 12h. After the reaction is complete, wait for the temperature to drop to room temperature, filter the product and dry it in a vacuum oven at 70℃ to obtain an orange powder crude product. Then use a Soxhlet extractor to purify the obtained crude product, and the selected extractant is tetrahydrofuran. After the crude product is loaded into the Soxhlet extractor, replace the air in the reaction system with nitrogen four times. Heat it to 65℃, turn on the stirring device, reflux for 36h, wait for the temperature to drop to room temperature, filter the product and dry it in a vacuum oven at 65℃ to obtain an orange powder of squaramide polymer.

[0046] Weigh 1,2,4,5-tetraaminobenzene hydrochloride (0.56g, 2mmol), nickel chloride (0.26g, 2mmol), and squarylamide polymer (0.19g, 1mmol); dissolve 1,2,4,5-tetraaminobenzene hydrochloride and in 15ml pure water respectively, and place in a low-temperature reaction tank to cool to 0℃, slowly drip concentrated ammonia (12M / L) into the 1,2,4,5-tetraaminobenzene hydrochloride solution until the reaction system is neutral, then slowly add nickel chloride solution and react at room temperature for 10h to obtain a metal coordination polymer solution. Finally, add the squarylamide polymer and continue stirring and reacting at room temperature for 12h. After the reaction is completed, filter and dry in vacuum at 70℃ to obtain a hydrogen-bonded heterojunction polymer powder.

[0047] The infrared spectrum results of the hydrogen-bonded heterojunction polymer show that compared with the squarylamide polymer and the coordination polymer, some functional groups of the hydrogen-bonded heterojunction polymer undergo red-shift or blue-shift, proving the existence of hydrogen-bonded interaction.

[0048] Preparation of the sensor:

[0049] (1) ultrasonically clean the interdigital electrodes using 10 ml of water, ethanol, and acetone in sequence, and dry them for later use;

[0050] (2) adding 4 mg of hydrogen-bonded heterojunction polymer to 2 g of ethanol by ultrasonic dispersion for 5 minutes to obtain a dispersion containing the hydrogen-bonded heterojunction polymer;

[0051] (3) The dispersion was brushed on the interdigital electrodes for 8 times, and the surface was dried before brushing again after each brushing. After brushing, the surface was left at room temperature, and after evaporation, it was placed in an oven at 70°C for 1 hour to obtain a nitrogen dioxide resistive sensor based on hydrogen bond heterojunction polymer with a film thickness of 300 μm.

[0052] The current response of the sensor under different concentrations of nitrogen dioxide is measured:

[0053] First, the device was placed in pure nitrogen conditions. After the current stabilized, the device was placed in a nitrogen dioxide atmosphere with different concentrations. After the current stabilized, the device was placed in pure nitrogen conditions again and the above cycle was repeated. The results show that the sensor can have a good response and recovery performance to nitrogen dioxide as low as 10ppb, and its response value is larger than that of square acid amide polymer and metal coordination polymer.

[0054] Example 3

[0055] Synthesis of Hydrogen Bonded Heterojunction Polymers:

[0056] Weigh p-phenylenediamine (0.55g, 5mmol), diethyl squarate (0.85g, 5mmol), toluene (46.1g, 0.5mol) and acetonitrile (20.5g, 0.5mol) and place them in a single-mouth pressure-resistant bottle. After loading the reflux device, replace the air in the reaction system with nitrogen four times. Then heat it to 125℃, turn on the stirring device, and reflux for 12h. After the reaction is complete, wait for the temperature to drop to room temperature, filter the product and dry it in a vacuum oven at 70℃ to obtain an orange powder crude product. Then use a Soxhlet extractor to purify the obtained crude product, and the selected extractant is tetrahydrofuran. After the crude product is loaded into the Soxhlet extractor, replace the air in the reaction system with nitrogen four times. Heat it to 65℃, turn on the stirring device, reflux for 36h, wait for the temperature to drop to room temperature, filter the product and dry it in a vacuum oven at 65℃ to obtain an orange powder of squaramide polymer.

[0057] Weigh a certain molar ratio of 1,2,4,5-tetraaminobenzene hydrochloride (0.28g, 1mmol.), nickel chloride (0.13g, 1mmol.), and squaramide polymer (0.38g, 2mmol.); dissolve 1,2,4,5-tetraaminobenzene hydrochloride and in 10ml pure water respectively, and place in a low-temperature reaction tank to cool to 0℃, slowly drip concentrated ammonia (12M / L) into the 1,2,4,5-tetraaminobenzene hydrochloride solution until the reaction system is neutral, then slowly add nickel chloride solution and react at room temperature for 10h. Finally, add squaramide polymer and continue stirring and reacting at room temperature for 12h. After the reaction is completed, filter and dry in vacuum at 70℃ to obtain hydrogen-bonded heterojunction polymer powder.

[0058] (2) Preparation of sensor:

[0059] Step 1: Use 10 ml of water, ethanol and acetone to ultrasonically clean the interdigital electrodes in order, and then dry them for later use;

[0060] Step 2, ultrasonically adding 4 mg of hydrogen-bonded heterojunction polymer into 2 g of acetone, and ultrasonically dispersing for 5 minutes to obtain a dispersion containing the hydrogen-bonded heterojunction polymer;

[0061] Step 3: Apply the dispersion on the interdigital electrodes 8 times, and apply again after the surface is dry after each application. After application, place it at room temperature, and after evaporation, place it in an oven at 60°C for 1 hour to obtain a hydrogen-bonded heterojunction polymer sensor with a film thickness of 300 μm.

[0062] (3) Current response measurement of nitrogen dioxide sensor based on hydrogen bond heterojunction polymer at different concentrations of nitrogen dioxide:

[0063] First, the device was placed in pure nitrogen conditions. After the current stabilized, the device was placed in a nitrogen dioxide atmosphere with different concentrations. After the current stabilized, the device was placed in pure nitrogen conditions again and the above cycle was repeated. The sensor based on hydrogen bond heterojunction polymer can have a good response and recovery performance to nitrogen dioxide as low as 10ppb, and its response value is larger than that of square acid amide polymer and metal coordination polymer.

[0064] In summary, the invention includes but is not limited to the above embodiments. Any equivalent substitution or partial improvement made under the spirit and principle of the invention shall be deemed to be within the protection scope of the invention.

Claims

1. A hydrogen-bonded heterojunction polymer, characterized in that: The polymer is a heterojunction structure formed by the interaction of a squarylamide polymer and a metal coordination polymer through hydrogen bonding, and the structural formula of the polymer is: Wherein, n is a positive integer.

2. A hydrogen-bonded heterojunction polymer according to claim 1, characterized in that: The molar ratio of the squarylamide polymer to the metal coordination polymer is 0.5 to 2:

1.

3. A method for preparing a hydrogen-bonded heterojunction polymer as claimed in claim 1 or 2, characterized in that: The method steps include: (1) Under a protective gas atmosphere, p-phenylenediamine and diethyl squarate are heated to react in a reaction solvent to obtain a crude product, which is purified to obtain a squarylamide polymer powder; (2) Add concentrated aqueous ammonia to an aqueous solution of 1,2,4,5-tetraaminobenzene hydrochloride at 0-5°C until the reaction system is neutral, then add an aqueous solution of nickel chloride to react to obtain a metal coordination polymer solution; add squarylamide polymer powder to the metal coordination polymer solution, react, filter, and vacuum dry to obtain a hydrogen bond heterojunction polymer.

4. The method for preparing a hydrogen-bonded heterojunction polymer according to claim 3, characterized in that: In step (1), the molar ratio of p-phenylenediamine, diethyl squarate and the reaction solvent is 1:1:100-300; The reaction solvent is a mixed solution of toluene and chloroform in a volume ratio of 1:1, or a mixed solution of toluene and acetonitrile in a volume ratio of 1:1; The reaction temperature is 90-130°C, and the reaction time is 9-16h.

5. A method for preparing a hydrogen-bonded heterojunction polymer as claimed in claim 3 or 4, characterized in that: In step (1), during purification, the crude product is added to an extraction solvent, heated and stirred at 70 to 90° C. for 24 to 48 hours under a protective gas atmosphere, naturally cooled, filtered, and vacuum dried at 60 to 90° C. to obtain a squarylamide polymer powder.

6. The method for preparing a hydrogen-bonded heterojunction polymer according to claim 3, characterized in that: In step (2), the concentrations of the aqueous solution of 1,2,4,5-tetraaminobenzene hydrochloride and the aqueous solution of nickel chloride are 0.01 to 1 mol / L, respectively.

7. A method for preparing a hydrogen-bonded heterojunction polymer according to claim 3 or 6, characterized in that: In step (2), the molar ratio of 1,2,4,5-tetraaminobenzene hydrochloride, nickel chloride and squarylamide polymer is 1:1:0.5-2.

8. A method for preparing a hydrogen-bonded heterojunction polymer according to claim 3 or 7, characterized in that: In step (2), the reaction time is 9 to 16 hours; and the vacuum drying temperature is 60 to 90°C.

9. A nitrogen dioxide resistive sensor, characterized in that: The interdigital electrodes of the sensor are coated with a hydrogen-bonded heterojunction polymer according to the present invention.

10. A nitrogen dioxide resistance sensor as claimed in claim 9, characterized in that: The sensor is prepared by the following method, the method steps comprising: (1) ultrasonically dispersing the hydrogen-bonded heterojunction polymer in a solvent to obtain a dispersion; the mass ratio of the hydrogen-bonded heterojunction polymer to the solvent is 1:400-600; and the ultrasonic time is 2-10 minutes; (2) applying the dispersion onto a clean interdigital electrode, removing the solvent by natural evaporation, and drying to obtain a nitrogen dioxide resistive sensor; Preferably, the solvent is one or more of ethanol, chloroform and acetone; Preferably, the brushing is completed with a brush pen, the brushing times are 5 to 10 times, and the surface is brushed again after each brushing. The interdigital electrode includes an aluminum oxide substrate and a silver-palladium alloy electrode, the interdigital width is 50 to 100 μm, the interdigital spacing is 200 to 300 μm, the aluminum oxide substrate thickness is 1 to 2 mm, and the silver-palladium alloy electrode thickness is 100 to 200 nm. The drying temperature is 50 to 80°C, and the drying time is 0.5 to 2 hours.

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