阅读说明：本技术 基于聚吡咯薄膜修饰的粗糙化的锥形宏弯光纤乙醇气体传感器 (Roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification ) 是由 侯钰龙 胡彦君 刘文怡 于 2019-11-16 设计创作，主要内容包括：本发明公开了一种基于聚吡咯薄膜修饰的粗糙化的锥形宏弯光纤乙醇气体传感器,涉及光纤传感器领域。传感器主要包括一根宏弯光纤,宏弯光纤上一定长度的一段为锥形宏弯结构,锥形宏弯结构为利用粗糙化加工后去掉了光纤包层及部分纤芯的剩余纤芯结构,锥形宏弯结构的表面上附着有聚吡咯薄膜,形成乙醇气体敏感探头,宏弯光纤位于锥形宏弯结构两端的光纤部分采用屏蔽外界光的黑色套管遮挡,宏弯光纤一端与LED光源连接,另一端与光功率计连接。同时还公开了该传感器的制备方法和检测方法。本发明提供的检测方法和制备方法比较简单,薄膜形态良好,可以满足在复杂空间结构内任意布置的检测需求,结构简单、成本较低。(The invention discloses a roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, and relates to the field of optical fiber sensors. The sensor mainly comprises a macrobend optical fiber, a section of the macrobend optical fiber with a certain length is a conical macrobend structure, the conical macrobend structure is a residual fiber core structure which is formed by removing an optical fiber cladding and a part of fiber core after roughening processing, a polypyrrole film is attached to the surface of the conical macrobend structure to form an ethanol gas sensitive probe, the optical fiber parts of the macrobend optical fiber at two ends of the conical macrobend structure are shielded by black sleeves for shielding external light, one end of the macrobend optical fiber is connected with an LED light source, and the other end of the macrobend optical fiber is connected with an optical power meter. Meanwhile, a preparation method and a detection method of the sensor are also disclosed. The detection method and the preparation method provided by the invention are simple, the film has good form, the detection requirements of random arrangement in a complex space structure can be met, the structure is simple, and the cost is low.)

1. A coarsened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification is characterized in that: the optical fiber power meter comprises a macrobend optical fiber, wherein a section of the macrobend optical fiber with a certain length is a conical macrobend structure, the conical macrobend structure is a residual fiber core structure which is subjected to roughening processing and then is provided with a fiber cladding and a part of fiber core, a polypyrrole film is attached to the surface of the conical macrobend structure to form an ethanol gas sensitive probe, the optical fiber parts of the macrobend optical fiber at two ends of the conical macrobend structure are shielded by black sleeves for shielding external light, one end of the macrobend optical fiber is connected with an LED light source, and the other end of the macrobend optical fiber is connected with an optical power meter.

2. The polypyrrole film modification-based roughened conical macrobend optical fiber ethanol gas sensor is characterized in that: the length of the conical macrobend structure is 2-3 cm.

3. The preparation method of the roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, as claimed in claim 1, is characterized in that: the method comprises the following steps:

① taking a plastic optical fiber, roughening one section of the fixed length, removing the optical fiber cladding and part of the fiber core at the section, and making the rest fiber core part have a conical macrobend structure;

② weigh 0.2164g FeCl₃Powder, pyrrole 3 ul; 10ml of deionized water was added to 0.2164g of FeCl₃Uniformly stirring the powder in a beaker, standing for half an hour, and depositing impurities at the bottom of the beaker; adding 3ul pyrrole into 10ml deionized water, stirring, and uniformly separating by using a magnetic stirrer; taking a glass culture dish with the diameter of 8cm, and adding FeCl₃Pouring the solution into a culture dish, adding the pyrrole solution, uniformly mixing, covering a cover, reacting at room temperature for 4 hours, and forming a layer of black and gray polypyrrole film on the surface of the reaction solution;

③ bending the plastic optical fiber to make the conical macrobend structure located at the head of the bent plastic optical fiber, then extending the bent head of the plastic optical fiber, namely the conical macrobend structure into a glass culture dish for 2-3min, and taking out to form an ethanol gas sensitive probe, namely obtaining the rough conical macrobend optical fiber ethanol gas sensor modified by the polypyrrole film;

④ shielding the plastic optical fiber parts at two sides of the conical macrobend structure with black sleeves;

⑤ one end of the plastic optical fiber is connected with the LED light source and the other end is connected with the optical power meter.

4. The preparation method of the roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, according to claim 3, is characterized in that: the roughening process is carried out by sanding.

5. The ethanol gas detection method of the polypyrrole film modified roughened conical macrobend optical fiber ethanol gas sensor, according to claim 1, is characterized in that: the method comprises the following steps:

①, connecting one end of a roughened conical macrobend optical fiber modified by a polypyrrole film with one side of an optical power meter, connecting the other end of the roughened conical macrobend optical fiber with an LED light source, connecting the other side of the optical power meter with a computer, wherein the LED light source is a light source with adjustable optical power;

② placing the roughened conical macrobend optical fiber decorated by polypyrrole film in the environment of the detected alcohol gas, the alcohol gas sensitive probe functions, when no alcohol gas exists in the environment, the power meter outputs stable value, when alcohol gas exists, the polypyrrole film and alcohol react with each other, the output power changes suddenly and falls, and the larger the alcohol concentration is, the faster the response is, the larger the power variation is, when the alcohol concentration is reduced, the output power value rises and recovers to stable value, the change of the power count value corresponds to the alcohol concentration, and the response and recovery time of the sensor gas is determined according to the rising and falling time.

Technical Field

The invention relates to the field of optical fiber sensors, in particular to a roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, which is suitable for detection of ethanol gas.

Background

Disclosure of Invention

The invention provides a roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, aiming at solving the problem that a sensor adopted for ethanol gas detection in the prior art is not suitable for detection at normal temperature and normal pressure.

The invention is realized by the following technical scheme: the utility model provides a toper macrobend optic fibre ethanol gas sensor based on coarsening of polypyrrole film modification, includes a macrobend optic fibre, one section of certain length is toper macrobend structure on the macrobend optic fibre, toper macrobend structure is for utilizing the surplus fibre core structure that has removed optic fibre covering and partial fibre core after the coarsening processing, the toper macrobend structure is attached to on the surface has the polypyrrole film, forms the gaseous sensitive probe of ethanol, the optical fiber part that macrobend optic fibre is located toper macrobend structure both ends adopts the black sleeve pipe of shielding external light to shelter from, macrobend optic fibre one end is connected with the LED light source, and the other end is connected with the optical power meter.

The invention utilizes the roughened conical macrobend optical fiber and the polypyrrole film to form a novel ethanol gas detection sensor. The polypyrrole film is prepared by excessive ferric chloride and pyrrole monomers to generate a film of um level, the surface of the optical fiber is roughened by using a rough machining mode, and the volume ratio of the surface area of the film attached to the optical fiber is increased by using a formed conical macrobend structure, wherein the conical macrobend structure refers to a shape formed by the fiber core after roughening machining. The polypyrrole film reacts with the ethanol gas, the refractive index of the surface of the polypyrrole film is changed, the refractive index is changed differently due to different ethanol concentrations, the final power output is different, and the concentration of the ethanol gas can be measured by using the principle. The technological method for modifying the polypyrrole film on the surface of the optical fiber provided by the invention combines the polypyrrole film with the tapered optical fiber, so that the measurement of ppm-level ethanol gas concentration is realized, and the response time is less than 50 s.

A preparation method of a roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification comprises the following steps:

① taking a plastic optical fiber, roughening one section of the fixed length, removing the optical fiber cladding and part of the fiber core at the section, and making the rest fiber core part have a conical macrobend structure;

② weigh 0.2164g FeCl₃Powder, pyrrole 3 ul; 10ml of deionized water was added to 0.2164g of FeCl₃Uniformly stirring the powder in a beaker, standing for half an hour, and depositing impurities at the bottom of the beaker; adding 3ul pyrrole into 10ml deionized water, stirring, and uniformly separating by using a magnetic stirrer; taking a glass culture dish with the diameter of 8cm, and adding FeCl₃Pouring the solution into a culture dish, adding the pyrrole solution, uniformly mixing, covering a cover, reacting at room temperature for 4 hours, and forming a layer of black and gray polypyrrole film on the surface of the reaction solution;

③ bending the plastic optical fiber to make the conical macrobend structure located at the head of the bent plastic optical fiber, then extending the bent head of the plastic optical fiber, namely the conical macrobend structure into a glass culture dish for 2-3min, and taking out to form an ethanol gas sensitive probe, namely obtaining the rough conical macrobend optical fiber ethanol gas sensor modified by the polypyrrole film;

④ shielding the plastic optical fiber parts at two sides of the conical macrobend structure with black sleeves;

⑤ one end of the plastic optical fiber is connected with the LED light source and the other end is connected with the optical power meter.

According to the preparation method of the roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, the polypyrrole film is prepared by using excessive ferric chloride, and the thickness of the film is reduced, so that the light transmittance is increased. Meanwhile, a polypyrrole film formed by oxidation-reduction reaction at room temperature can keep the film shape; and the rough surface of the plastic optical fiber is processed (by using tools such as sand paper and the like), the optical fiber cladding and part of the optical fiber core are removed, the conical macrobend structure is manufactured, the rough surface of the optical fiber can enable the optical fiber to be tightly attached to the polypyrrole film, the evanescent wave strength is increased by bending the optical fiber, and the sensitivity is improved.

The ethanol gas detection method of the roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification comprises the following steps:

①, connecting one end of a roughened conical macrobend optical fiber modified by a polypyrrole film with one side of an optical power meter, connecting the other end of the roughened conical macrobend optical fiber with an LED light source, connecting the other side of the optical power meter with a computer, wherein the LED light source is a light source with adjustable optical power;

② placing the roughened conical macrobend optical fiber decorated by polypyrrole film in the environment of the detected alcohol gas, the alcohol gas sensitive probe functions, when no alcohol gas exists in the environment, the power meter outputs stable value, when alcohol gas exists, the polypyrrole film and alcohol react with each other, the output power changes suddenly and falls, and the larger the alcohol concentration is, the faster the response is, the larger the power variation is, when the alcohol concentration is reduced, the output power value rises and recovers to stable value, the change of the power count value corresponds to the alcohol concentration, and the response and recovery time of the sensor gas is determined according to the rising and falling time.

The invention provides an ethanol gas detection method of a roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, which has the following principle: when the surface of the optical fiber attached with the polypyrrole film meets ethanol gas, because ethanol has reducibility and can be used for volatilizing electrons, the polypyrrole is a P-type polymer, the concentration of a hole is greater than that of an electron, when the polypyrrole film and the electron contact with each other, the reaction occurs, so that the concentration of the hole of the polypyrrole is reduced, the refractive index of the polypyrrole is changed, the coupling rate of the optical fiber sensor is changed along with the change of the concentration of the hole of the polypyrrole, the pulse intensity is suddenly changed, and the gas concentration can be obtained correspondingly. The method can monitor the change of concentration in real time, and can realize high-precision gas concentration detection by a method with low cost and simple structure.

Compared with the prior art, the invention has the following beneficial effects: according to the roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, the preparation method and the detection method, the excessive ferric chloride and pyrrole are used for preparing the um-level polypyrrole film, the method is simple, and the film is good in shape; the detection of ethanol gas can be realized by utilizing the polypyrrole film and the conical plastic optical fiber, the detection requirement of random arrangement in a complex space structure can be met, the structure is simple, the cost is low, and non-contact measurement can be carried out; the optical fiber is polished by methods such as sand paper and the like to be conical, the rough surface of the optical fiber can enable the optical fiber to be tightly attached to the polypyrrole film, the gas detection sensitivity can be increased, meanwhile, the film is not easy to fall off, and the method is suitable for multiple tests. The intensity of evanescent waves is increased by bending the optical fiber into a U shape; meanwhile, the gas sensor can be applied to gas detection in communication, post and telecommunications, financial systems, libraries, museums, archives, airports, oil depots, petroleum, petrochemical, pharmaceutical and other industries in the future.

Drawings

Fig. 1 is a schematic rough surface of a 2cm long tapered macrobend structure polished according to an embodiment of the present invention.

Fig. 2 is a schematic view of a macrobend structure of a polypyrrole film plated on a tapered macrobend structure of a macrobend optical fiber in the present invention.

FIG. 3 is a schematic diagram illustrating the detection principle of the ethanol gas sensor according to the present invention.

Fig. 4 is an assembly diagram of an experimental detection device according to an embodiment of the present invention.

FIG. 5 is a graph of the time response of the power of a comparative example of PPy1 according to an embodiment of the present invention as a function of ethanol concentration.

FIG. 6 is a graph of the time response of power as a function of ethanol concentration for an example of PPy2 according to an embodiment of the present invention.

FIG. 7 is a graph of the time response of the power of a comparative example of PPy3 according to an embodiment of the present invention as a function of ethanol concentration.

FIG. 8 is a graph of power as a function of concentration for three examples.

FIG. 9 is a diagram of polypyrrole films prepared in three examples.

The figures are labeled as follows: the device comprises a 1-polypyrrole film, a 2-macrobend optical fiber, a 3-ethanol gas sensitive probe, a 4-black sleeve, a 5-fiber core, a 6-optical power meter, a 7-LED light source, an 8-computer, a 9-ethanol gas concentration meter, a 10-USB connector and an 11-gas experimental box.

Detailed Description

The present invention is further illustrated by the following specific examples.

The utility model provides a toper macrobend optic fibre ethanol gas sensor based on coarsening of polypyrrole film modification, as shown in fig. 1~2, includes a macrobend optic fibre, a section of certain length is toper macrobend structure on the macrobend optic fibre, toper macrobend structure is for utilizing the remaining fiber core structure that has removed optic fibre cladding and partial fibre core after the roughening processing, the polypyrrole film is attached to on the surface of toper macrobend structure, forms the gaseous sensitive probe of ethanol, the optical fiber part that macrobend optic fibre is located toper macrobend structure both ends adopts the black sleeve pipe of shielding external light to shelter from, macrobend optic fibre one end is connected with the LED light source, and the other end is connected with the optical power meter.

In this embodiment, the length of the conical macrobend structure is 2-3 cm.

A preparation method of a roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification comprises the following steps:

① taking a plastic optical fiber, roughening one section of the fixed length, removing the optical fiber cladding and part of the fiber core at the section, and the remaining fiber core part in the section is a conical macrobend structure, wherein the roughening is performed by sand paper grinding in the embodiment, but not limited to this processing mode;

② weigh 0.2164g FeCl₃Powder, pyrrole 3 ul; 10ml of deionized water was added to 0.2164g of FeCl₃Uniformly stirring the powder in a beaker, standing for half an hour, and depositing impurities at the bottom of the beaker; adding 3ul pyrrole into 10ml deionized water, stirring, and uniformly separating by using a magnetic stirrer; taking a glass culture dish with the diameter of 8cm, and adding FeCl₃The solution is poured into a petri dish and thenAdding a pyrrole solution, uniformly mixing, covering a cover, reacting at room temperature for 4 hours to form a layer of black and gray polypyrrole film on the surface of the reaction solution;

③ bending the plastic optical fiber to make the conical macrobend structure located at the head of the bent plastic optical fiber, then extending the bent head of the plastic optical fiber, namely the conical macrobend structure into a glass culture dish for 2-3min, and taking out to form an ethanol gas sensitive probe, namely obtaining the rough conical macrobend optical fiber ethanol gas sensor modified by the polypyrrole film;

④ shielding the plastic optical fiber parts at two sides of the conical macrobend structure with black sleeves;

⑤ one end of the plastic optical fiber is connected with the LED light source and the other end is connected with the optical power meter.

The ethanol gas detection method of the roughened conical macrobend optical fiber ethanol gas sensor based on polypyrrole film modification, as shown in fig. 3, comprises the following steps:

①, connecting one end of a roughened conical macrobend optical fiber modified by a polypyrrole film with one side of an optical power meter, connecting the other end of the roughened conical macrobend optical fiber with an LED light source, connecting the other side of the optical power meter with a computer, wherein the LED light source is a light source with adjustable optical power;

② placing the roughened conical macrobend optical fiber decorated by polypyrrole film in the environment of the detected alcohol gas, the alcohol gas sensitive probe functions, when no alcohol gas exists in the environment, the power meter outputs stable value, when alcohol gas exists, the polypyrrole film and alcohol react with each other, the output power changes suddenly and falls, and the larger the alcohol concentration is, the faster the response is, the larger the power variation is, when the alcohol concentration is reduced, the output power value rises and recovers to stable value, the change of the power count value corresponds to the alcohol concentration, and the response and recovery time of the sensor gas is determined according to the rising and falling time.

In the embodiment, two comparison examples are also used for detection and comparison, the two comparison examples adopt iron chloride oxidant and pyrrole reactant with different mass ratios to prepare the polypyrrole film, the prepared polypyrrole film is plated on the conical macrobend structure, and the detection is carried out, and the specific process is as follows:

0.1443g, 0.2164g and 0.2885g of FeCl were weighed respectively₃And adding 10ml of deionized water into the powder respectively, uniformly stirring in a beaker, standing for half an hour, and depositing impurities at the bottom of the beaker. In addition, three portions of 12ul pyrrole were dissolved in 10ml deionized water and uniformly separated by a magnetic stirrer. Taking three glass culture dishes with the diameter of 8cm, and adding FeCl₃The solution was poured into a petri dish, then the pyrrole solution was slowly added, mixed evenly, covered with a lid, and reacted at room temperature for 4h to form a dark gray PPy film on the surface, as shown in fig. 9. Thus, 3 different concentrations of polypyrrole sensitive films were prepared, which were designated ppy-1, ppy-2, ppy-3. The mass ratios between the ferric chloride oxidant and the pyrrole reactant of the three polypyrrole films prepared at this time were 5:1, 15:2, and 10:1, respectively.

After the experimental device is connected with equipment according to the graph in fig. 4, the gas response and recovery time of the sensitive probe prepared by the three ppy-1, ppy-2, ppy-3 polypyrrole films to the ethanol gas are tested, as shown in fig. 5 to 7, when the optical power meter value is decreased after the gas is injected, and the ethanol gas is extracted, the value is increased and recovered to a stable value, and it can be seen from the graph that the response and recovery time of the sensor prepared by the ppy-2 film are better than those of the sensors prepared by the other two sensitive films under the same concentration. Therefore, the response and recovery time of the sensor gas are determined from the time of the rise and fall while the ethanol concentration is corresponded to the change in the power count value. This experiment tested the change in sensor response between ethanol concentration 700-. FIG. 8 is a graph of power as a function of concentration, showing that the sensor made with the ppy-2 film is most sensitive, with the slope of the curve being the greatest, and the ppy-1 times and ppy-3 changes being the least, depending on its film thickness and the degree of closeness of fit between the sensors.

The scope of the invention is not limited to the above embodiments, and various modifications and changes may be made by those skilled in the art, and any modifications, improvements and equivalents within the spirit and principle of the invention should be included in the scope of the invention.