阅读说明：本技术 聚偏二氟乙烯/聚（2-丙烯酰胺-2-甲基丙磺酸）掺杂聚苯胺膜氨气传感器及制备方法 (Polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline film ammonia gas sensor and preparation method thereof ) 是由 沈文锋 吕大伍 宋伟杰 谭瑞琴 于 2019-09-10 设计创作，主要内容包括：本发明公开了一种聚偏二氟乙烯/聚(2-丙烯酰胺-2-甲基丙磺酸)掺杂的聚苯胺膜氨气传感器,包括聚偏二氟乙烯层、聚(2-丙烯酰胺-2-甲基丙磺酸)掺杂的聚苯胺层、叉指电极层。本发明制备的传感器对氨气的检测具有高灵敏度,高选择性和高稳定性；本发明可以通过调控聚(2-丙烯酰胺-2-甲基丙磺酸)、苯胺和过硫酸铵的浓度,来调节聚苯胺膜层的导电性和气敏性能,本发明具有小型化,室温工作的优势,从而可降低功耗,同时本发明具有可规模化生产,低成本的优势,有利于工业化生产。另外,本发明剩余溶液经过滤、干燥后可得到聚苯胺,减少浪费,节约成本。(The invention discloses a polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline film ammonia gas sensor which comprises a polyvinylidene fluoride layer, a poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline layer and an interdigital electrode layer. The sensor prepared by the invention has high sensitivity, high selectivity and high stability for detecting ammonia gas; the invention can adjust the conductivity and gas-sensitive property of the polyaniline film layer by regulating and controlling the concentrations of poly (2-acrylamide-2-methylpropanesulfonic acid), aniline and ammonium persulfate, has the advantages of miniaturization and room-temperature work, thereby reducing power consumption, and simultaneously has the advantages of large-scale production and low cost, and is beneficial to industrial production. In addition, the polyaniline can be obtained after the residual solution is filtered and dried, so that the waste is reduced, and the cost is saved.)

1. The polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline film ammonia gas sensor is characterized by sequentially comprising a polyvinylidene fluoride layer, a poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline layer and an interdigital electrode layer.

2. The polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) -doped polyaniline film ammonia gas sensor of claim 1, wherein the poly (2-acrylamide-2-methylpropanesulfonic acid) -doped polyaniline layer is grown on the polyvinylidene fluoride porous film layer by an in-situ growth method.

3. The polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) -doped polyaniline film ammonia gas sensor according to claim 1, wherein the interdigital electrode layer is formed by depositing a conductive material on the polyaniline layer through screen printing, ink-jet printing and sputtering deposition.

4. The polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) -doped polyaniline film ammonia gas sensor of claim 3, wherein the conductive material is one of a silver conductive ink or a copper conductive ink.

5. A method for preparing the polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) -doped polyaniline film ammonia gas sensor as described in any one of claims 1 to 4, which comprises the following steps:

(1) sequentially and respectively soaking a polyvinylidene fluoride porous membrane in ethanol and acetone, and ultrasonically cleaning for 15-20 minutes generally; then heat-treating at 50-150 deg.C for 10-100 min;

(2) adding 1-13g of 2-acrylamide-2-methylpropanesulfonic acid into a container filled with 75ml of deionized water, then carrying out magnetic stirring for 10-300 minutes, adding 1-5g of potassium persulfate into the solution, and then carrying out magnetic stirring for 10-100 minutes;

(3) putting the solution into an oil bath kettle preheated to 50-100 ℃, introducing nitrogen into the solution in the reaction process, and reacting for 1-6 h;

(4) cooling the solution to room temperature, then pouring the solution into a beaker, adding 500ml of acetone into the beaker, standing for 10-60min, carrying out centrifugal treatment, repeating the acetone addition and the centrifugal treatment for one to three times, finally collecting the precipitate, carrying out heat treatment at 40-80 ℃ for 200-1200 min, and grinding the obtained solid substance into powder for later use;

(5) adding 1-10g of the powder obtained in the step (4) into 100-300ml of deionized water, magnetically stirring for 10-300 minutes, adding 0.01-3g of aniline, ultrasonically oscillating for 10-100 minutes, putting the polyvinylidene fluoride porous membrane treated in the step (1) into the solution to obtain a solution A, and putting the solution A into ice water;

(6) adding 1-10g of ammonium persulfate into 20ml of deionized water, carrying out ultrasonic oscillation for 5-100 minutes, adding the obtained solution into the solution A, and keeping the solution in ice water for reaction for 5-30 hours;

(7) taking out the polyvinylidene fluoride porous membrane, washing with deionized water, and then carrying out heat treatment at 30-150 ℃ for 1-10 h;

(8) depositing one of silver conductive ink and copper conductive ink on the polyvinylidene fluoride porous membrane by screen printing, ink-jet printing or sputtering, and then carrying out heat treatment at 40-200 ℃ for 30-200 minutes.

Technical Field

The invention relates to a gas sensor, in particular to a detection sensor for ammonia gas, and also relates to a preparation method thereof.

Background

Today, the problem of atmospheric pollution is undoubtedly affecting the normal production and living activities of human beings. It is known that ammonia gas has serious harm to human health due to its high toxicity and strong corrosiveness, and in addition, ammonia gas is also a potential biomarker for diagnosing diseases such as uremia and duodenal ulcer in the detection of respiratory gas components of human bodies. Therefore, the development of the high-performance flexible room-temperature gas sensor has important significance in the fields of environmental detection, human health early warning, military, national defense and the like.

Since the relevant gas in the human respiratory gas, which reflects the human health condition, generally has low concentration and complex composition factors, there are high sensitivity and high selectivity requirements for the gas sensor for human health condition early warning. In order to achieve the purpose of industrial production, the sensor also needs to have the advantages of high stability, low cost, simple manufacture, large-scale manufacture and the like. Further, in practical applications of products, flexibility, low-temperature operation, low power consumption, miniaturization, integration, wireless, and the like are generally required. Currently, the sensitive materials for ammonia detection are generally classified into four types: metal oxides, carbon tubes, graphene, and organic polymers. The metal oxide material is a conventional gas-sensitive material for gas detection at present, but the metal oxide generally needs a very high working temperature, so that the power consumption is large, and the detected concentration of the metal oxide is mostly above ppm level, so that the metal oxide material is not suitable for wearable equipment applied to the aspect of human body breathing gas detection. And carbon tubes and graphene materials generally have the defects of low sensitivity, poor selectivity and the like. The organic polymer has the advantages of room-temperature working, high sensitivity, simple manufacturing method, good stability and the like, and is an important research material in the aspect of ammonia gas detection at present. However, generally, the sensor is made of an organic polymer such as polyaniline by dissolving the powder in an organic solvent (e.g., hexafluoroisopropanol, and azomethylpyrrolidone), and then coating the powder on the electrode by means of dropping or spin coating. The sensor manufactured by the method has the defects of low sensitivity, poor stability, complex manufacturing and the like. In addition, the invention patent CN 109613069 discloses a preparation method of an ammonia gas sensor of a polyvinylidene fluoride and polyaniline composite flexible membrane, but in the preparation method, the polyaniline is polymerized by using hydrochloric acid as protonic acid, and finally the detection of ammonia gas reaches 100 ppb. But the detection of ammonia in human respiratory gas with lower concentration has higher requirement for the detection limit of ammonia.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the high-efficiency ammonia gas sensor based on the polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline composite flexible membrane, and the performance of the obtained gas sensor is greatly improved compared with other ammonia gas sensors.

The technical scheme of the invention is to provide a high-efficiency ammonia gas sensor based on a polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline composite flexible membrane, which comprises a polyvinylidene fluoride layer, a poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline layer and an interdigital electrode layer.

Further, a poly (2-acrylamide-2-methylpropanesulfonic acid) -doped polyaniline layer is grown on the polyvinylidene fluoride porous membrane layer by adopting an in-situ growth method.

Further, the interdigital electrode layer is formed by depositing a conductive material on the polyaniline layer by a screen printing method, an ink-jet printing method or the like; wherein the conductive material is one of silver conductive ink or copper conductive ink.

The invention also provides a preparation method of the high-efficiency ammonia gas sensor based on the polyvinylidene fluoride/poly (2-acrylamide-2-methylpropanesulfonic acid) doped polyaniline composite flexible membrane, which comprises the following steps:

(1) sequentially and respectively soaking a polyvinylidene fluoride porous membrane in ethanol and acetone, and ultrasonically cleaning for 15-20 minutes generally; then heat-treating at 50-150 deg.C for 10-100 min;

(2) adding 1-13g of 2-acrylamide-2-methylpropanesulfonic acid into a container filled with 75ml of deionized water, then carrying out magnetic stirring for 10-300 minutes, adding 1-5g of potassium persulfate into the solution, and then carrying out magnetic stirring for 10-100 minutes;

(3) putting the solution into an oil bath kettle preheated to 50-100 ℃, introducing nitrogen into the solution in the reaction process, and reacting for 1-6 h;

(4) cooling the solution to room temperature, then pouring the solution into a beaker, adding 500ml of acetone with the volume of 200-;

(5) adding 1-10g of the powder obtained in the step (4) into 100-300ml of deionized water, magnetically stirring for 10-300 minutes, adding 0.01-3g of aniline, ultrasonically oscillating for 10-100 minutes, putting the polyvinylidene fluoride porous membrane treated in the step (1) into the solution to obtain a solution A, and putting the solution A into ice water;

(6) adding 1-10g of ammonium persulfate into 20ml of deionized water, carrying out ultrasonic oscillation for 5-100 minutes, adding the obtained solution into the solution A, and keeping the solution in ice water for reaction for 5-30 hours;

(7) taking out the polyvinylidene fluoride porous membrane, washing with deionized water, and then carrying out heat treatment at 30-150 ℃ for 1-10 h;

(8) depositing one of silver conductive ink and copper conductive ink on the polyvinylidene fluoride porous membrane by screen printing, ink-jet printing or sputtering, and then carrying out heat treatment at 40-200 ℃ for 30-200 minutes.

The invention has the advantages and beneficial effects that:

the sensor prepared by the invention has high sensitivity and better response to low-concentration ammonia gas (30 ppb); high selectivity, and has larger response to ammonia gas only; high stability, and basically unchanged initial resistance after multiple measurements.

The invention can adjust the conductivity and gas-sensitive property of the polyaniline film layer by regulating and controlling the concentrations of poly (2-acrylamide-2-methylpropanesulfonic acid), aniline and ammonium persulfate, has the advantages of miniaturization and room-temperature work, thereby reducing power consumption, and simultaneously has the advantages of large-scale production and low cost, and is beneficial to industrial production. In addition, the polyaniline can be obtained after the residual solution is filtered and dried, so that the waste is reduced, and the cost is saved.

The invention has the advantages of simple manufacture, low cost, mild reaction conditions and good controllability, and is beneficial to industrial production.

Drawings

Fig. 1 shows response tests of the ammonia gas sensor prepared in example 1 of the present invention to ammonia gas of different concentrations.

FIG. 2 is a graph showing the selectivity test of the ammonia gas sensor prepared in example 1 of the present invention for various gases.

Fig. 3 is a graph showing the resistance change of the ammonia gas sensor prepared in example 1 of the present invention after repeated several times.

Fig. 4 is a test of the stability of the long-term response performance of the ammonia gas sensor prepared in example 1 of the present invention.

FIG. 5 is a schematic diagram of a performance test flow of the ammonia gas sensor prepared by the invention.

Detailed Description

The present invention will be further described with reference to the following embodiments.