Efficient ammonia gas sensor based on polypyrrole composite flexible membrane and preparation thereof
阅读说明：本技术 以聚吡咯复合柔性膜为基的高效氨气传感器及其制备 (Efficient ammonia gas sensor based on polypyrrole composite flexible membrane and preparation 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：本发明公开了一种以聚吡咯复合柔性膜为基的高效氨气传感器,包括柔性膜层、聚吡咯层、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吡咯和过硫酸铵的浓度,来调节聚吡咯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 high-efficiency ammonia gas sensor based on a polypyrrole composite flexible membrane, which comprises a flexible membrane layer, a polypyrrole 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 method can adjust the conductivity and gas-sensitive property of the polypyrrole film layer by regulating and controlling the concentration of pyrrole and ammonium persulfate, has the advantages of miniaturization and room-temperature working, 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 efficient ammonia gas sensor based on the polypyrrole composite flexible membrane is characterized by sequentially comprising a flexible membrane layer, a polypyrrole layer and an interdigital electrode layer.
2. The efficient ammonia gas sensor based on the polypyrrole composite flexible film according to claim 1, wherein the polypyrrole layer grows on the flexible film layer by an in-situ growth method.
3. The efficient ammonia gas sensor based on the polypyrrole composite flexible film according to claim 1, wherein the flexible film is made of one of polyvinylidene fluoride, polyimide, polyurethane and polymethyl methacrylate.
4. The efficient ammonia gas sensor based on the polypyrrole composite flexible film according to claim 1, wherein the interdigital electrode layer is formed by depositing a conductive material on the polypyrrole layer by screen printing, ink-jet printing and sputtering deposition methods; wherein the conductive material is one of silver conductive ink or copper conductive ink.
5. The method for preparing the efficient ammonia gas sensor based on the polypyrrole composite flexible film as claimed in any one of claims 1 to 4, is characterized by comprising the following steps:
(1) sequentially and respectively soaking the flexible 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 0.01-3g of pyrrole into 100-300ml of 1M HCl, magnetically stirring for 10-300 minutes, putting the flexible membrane treated in the step (1) into the solution to obtain a solution A, and putting the solution A into ice water;
(3) adding 0.01-6g of ammonium persulfate into 20ml of 1M HCl, ultrasonically oscillating for 5-100 minutes, adding the obtained solution into the solution A, and keeping the solution in ice water for reacting for 10-100 min;
(4) taking out the flexible film, washing with deionized water, and then carrying out heat treatment at 30-150 ℃ for 1-10 h;
(5) one of silver conductive ink and copper conductive ink is deposited on the flexible film by silk screen printing, ink-jet printing or sputtering, and then is subjected to 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 well known that ammonia gas, NH, is a serious health hazard to humans due to its high toxicity and strong corrosiveness3The exposure limits to humans are 25ppm (8 hours) and 35ppm (10 minutes). Furthermore, NH3Is considered to be an environmentA contaminant because it has high activity and forms aerosols, such as ammonium nitrate and ammonium sulfate, when it reacts with nitric acid and sulfuric acid, respectively, in the air. Thus, these nanoscale NH3Aerosols produce smoke and exhibit a cooling effect, thereby negatively affecting the global greenhouse gas balance. 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.
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 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, organic polymers such as polyaniline and polythiophene are generally found in related researches, and NH prepared by the organic materials is discovered in related researches3The sensor generally has the defects of poor long-term stability and easy influence of temperature and humidity.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the high-efficiency ammonia gas sensor based on the polypyrrole composite flexible membrane, and compared with other ammonia gas sensors, the performance of the obtained gas sensor is greatly improved.
The technical scheme of the invention is to provide a high-efficiency ammonia gas sensor based on a polypyrrole composite flexible membrane, which is characterized by sequentially comprising a flexible membrane layer, a polypyrrole layer and an interdigital electrode layer.
Further, the flexible film layer may be polyvinylidene fluoride, polyimide, polyurethane, polymethyl methacrylate, or the like.
Further, the polypyrrole layer is grown on a flexible film, such as a polyvinylidene fluoride porous film layer, using an in-situ growth method.
Further, the interdigital electrode layer is formed by depositing a conductive material on the polypyrrole 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 efficient ammonia gas sensor based on the polypyrrole composite flexible membrane, which comprises the following steps:
(1) sequentially and respectively soaking the flexible 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 0.01-3g of pyrrole into 100-300ml of 1M HCl, magnetically stirring for 10-300 minutes, putting the flexible membrane treated in the step (1) into the solution to obtain a solution A, and putting the solution A into ice water;
(3) adding 0.01-6g of ammonium persulfate into 20ml of 1M HCl, ultrasonically oscillating for 5-100 minutes, adding the obtained solution into the solution A, and keeping the solution in ice water for reacting for 10-100 min;
(4) taking out the flexible film, washing with deionized water, and then carrying out heat treatment at 30-150 ℃ for 1-10 h;
(5) one of silver conductive ink and copper conductive ink is deposited on the flexible film by silk screen printing, ink-jet printing or sputtering, and then is subjected to heat treatment at 40-200 ℃ for 30-200 minutes.
The invention has the advantages and beneficial effects that:
the sensor prepared by the invention is NH taking polypyrrole as a base3Has good stability and is not easily influenced by temperature and humidity, and can be used for preparing NH3The test of related products has better response to low-concentration ammonia gas, the test limit reaches 5ppm, and the sensitivity is high; high selectivity and large response to ammonia gas only(ii) a High stability, and basically unchanged initial resistance after multiple measurements. The method can adjust the conductivity and gas-sensitive property of the polypyrrole film layer by regulating and controlling the concentration of pyrrole and ammonium persulfate, has the advantages of miniaturization and room-temperature working, 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 shows the response value change of the ammonia gas sensor prepared in example 1 of the present invention after repeated multiple 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 shows ammonia gas test conditions of the ammonia gas sensor prepared in example 1 of the present invention at different humidities.
FIG. 6 shows ammonia gas test conditions of the ammonia gas sensor prepared in example 1 of the present invention at different temperatures.
FIG. 7 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.