A peanut-shaped optical fiber humidity sensor and its preparation method

Abstract

The present invention relates to a peanut-shaped optical fiber humidity sensor and a preparation method thereof, the method comprising: a: preparing an optical fiber with a peanut-shaped structure by using a single-mode optical fiber; b: preparing nanofibers of a moisture-sensitive material by using electrostatic spinning, and annealing the nanofibers; c: coating the annealed nanofibers on the optical fiber with a peanut-shaped structure to form a nanofiber membrane, so as to obtain a peanut-shaped optical fiber humidity sensor. The preparation method of the peanut-shaped optical fiber humidity sensor of this embodiment uses electrostatic spinning technology to coat the nanofiber membrane of the moisture-sensitive material on the optical fiber with a peanut-shaped structure. Compared with coating the moisture-sensitive material, the nanofibers can be stably coated on the surface of the optical fiber and are evenly distributed, thereby improving the measurement accuracy of the optical fiber temperature and humidity sensor.

Description

Technical Field

[0001] The invention belongs to the technical field of sensors, and in particular relates to a peanut-shaped optical fiber humidity sensor and a preparation method thereof. Background Art

[0002] Humidity sensing devices are used in a variety of environmental monitoring applications, including human comfort, agriculture, and food processing and storage. Fiber optic humidity sensors offer advantages over conventional electronic sensors, including high sensitivity and resistance to chemical corrosion and electromagnetic interference. Consequently, fiber optic sensors are gaining increasing attention and experiencing rapid development in modern society, offering a wide range of applications.

[0003] A fiber optic sensor detects changes in optical signals caused by changes in the state of the object being measured. An incident light beam from a light source is sent through an optical fiber to a modulator. Within the modulator, the light interacts with the external measured parameter, causing changes in the optical properties of the light, such as intensity, wavelength, frequency, and phase. This modulated light signal is then sent through the optical fiber to an optoelectronic device, where it is finally demodulated to obtain the measured parameter. Optical fiber serves as both a transmission fiber and an optical modulator.

[0004] Currently, most optical fibers use a tapered fiber structure. To achieve high sensitivity, the tapered region must be several microns wide, resulting in low mechanical strength and poor operational performance. Most humidity sensors use a coating method with humidity-sensitive materials, which increases the complexity of the sensor's manufacturing process. Furthermore, uneven coating can affect sensor measurement accuracy, and the coating thickness cannot be precisely controlled. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a peanut-shaped optical fiber humidity sensor and a method for preparing the same. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] The present invention provides a method for preparing a peanut-shaped optical fiber humidity sensor, comprising:

[0007] a: A fiber with a peanut-shaped structure is prepared using a single-mode fiber;

[0008] b: Nanofibers of humidity-sensitive materials were prepared by electrospinning and annealed;

[0009] c: The annealed nanofibers are coated on the optical fiber with a peanut-shaped structure to form a nanofiber membrane, so as to obtain a peanut-shaped optical fiber humidity sensor.

[0010] In one embodiment of the present invention, step a comprises:

[0011] a1: using a fiber fusion splicer to discharge the end of the single-mode optical fiber, so as to fuse the end of the single-mode optical fiber to form a spherical structure;

[0012] a2: Using the fusion mode of the optical fiber fusion splicer, the two single-mode optical fibers with spherical structures are fused to form an optical fiber with a peanut-shaped structure.

[0013] In one embodiment of the present invention, the diameter of the spherical structure is 200-250 μm.

[0014] In one embodiment of the present invention, in step a1, two discharges are used to melt the end of the single-mode optical fiber to form a spherical structure, wherein the first discharge intensity is 150 bits and the discharge time is 150 ms, and the second discharge intensity is 300 bits and the discharge time is 4 s.

[0015] In one embodiment of the present invention, in step a2, the two spherical structures of the single-mode optical fiber are placed next to each other, and the discharge intensity is set to 25 bits through the debugging mode of the fusion splicer, and the two spherical structures are fused to form a peanut-shaped structure.

[0016] In one embodiment of the present invention, the nanofibers are ZnO nanofibers.

[0017] In one embodiment of the present invention, step b comprises:

[0018] b1: prepare ZnO precursor solution;

[0019] b2: Use a syringe to draw up the ZnO precursor solution. The syringe is mounted on the propulsion device of the electrospinning machine. The distance between the syringe and the grounded metal plate is 15-18 cm. Tin foil is placed on the metal plate to collect the nanofibers.

[0020] b3: Align the syringe with the tinfoil and perform electrospinning, where the electric field strength is 18 kV;

[0021] b4: The nanofibers collected from the tinfoil were annealed to obtain disordered ZnO nanofibers, wherein the annealing temperature was 500°C, the annealing time was 3 h, and the annealing heating rate was 1°C / min -1 .

[0022] In one embodiment of the present invention, step c includes: placing the optical fiber with a peanut-shaped structure on the ZnO nanofiber, and rotating the optical fiber with a peanut-shaped structure so that the ZnO nanofiber is coated thereon to form a nanofiber membrane, so as to obtain a peanut-shaped optical fiber humidity sensor.

[0023] The present invention provides a peanut-shaped optical fiber humidity sensor, comprising an optical fiber with a peanut-shaped structure and a nanofiber membrane of a humidity-sensitive material coated thereon, wherein the peanut-shaped optical fiber humidity sensor is prepared using the preparation method described in any one of the above embodiments.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The peanut-shaped fiber optic humidity sensor of the present invention utilizes electrospinning technology to coat a nanofiber membrane of a humidity-sensitive material on the peanut-shaped optical fiber. Compared to coating the fiber with a humidity-sensitive material, the nanofibers can be stably and evenly coated on the optical fiber surface, thereby improving the measurement accuracy of the optical fiber temperature and humidity sensor.

[0026] 2. The peanut-shaped optical fiber humidity sensor fabricated in the present invention has a higher mechanical strength and is less prone to breakage than a tapered optical fiber.

[0027] 3. The preparation method of the peanut-shaped optical fiber humidity sensor of the present invention first prepares nanofibers, and then winds the annealed nanofibers on the optical fiber to form a nanofiber membrane. This can avoid the problem of directly spraying the nanofibers on the optical fiber through electrospinning to form a nanofiber membrane, and then annealing the optical fiber and the nanofibers together, which causes the optical fiber to become brittle and easy to break.

[0028] 4. The peanut-shaped optical fiber humidity sensor of the present invention is simple to manufacture and can be prepared using only ordinary single-mode optical fiber at low cost.

[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of a method for preparing a peanut-shaped optical fiber humidity sensor provided by an embodiment of the present invention;

[0031] Figure 2 This is an optical microscope photograph of an optical fiber with a peanut-shaped structure provided by an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of the electrospinning process provided by an embodiment of the present invention;

[0033] Figure 4 is a scanning electron microscope photograph of the nanofiber provided by an embodiment of the present invention;

[0034] Figure 5 This is a scanning electron microscope photograph of an optical fiber with a peanut-shaped structure coated with a nanofiber membrane provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of a peanut-shaped optical fiber humidity sensor and a preparation method thereof proposed in accordance with the present invention in combination with the accompanying drawings and specific embodiments.

[0036] The aforementioned and other technical contents, features, and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a deeper and more specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are provided for reference and illustration purposes only and are not intended to limit the technical solutions of the present invention.

[0037] Example 1

[0038] See Figure 1 , Figure 1 This is a flow chart of a method for preparing a peanut-shaped optical fiber humidity sensor provided by an embodiment of the present invention. As shown in the figure, the preparation method includes:

[0039] a: A fiber with a peanut-shaped structure is prepared using a single-mode fiber;

[0040] b: Nanofibers of humidity-sensitive materials were prepared by electrospinning and annealed;

[0041] c: The annealed nanofibers are coated on an optical fiber with a peanut-shaped structure to form a nanofiber membrane to obtain a peanut-shaped optical fiber humidity sensor.

[0042] The peanut-shaped optical fiber humidity sensor fabricated in this embodiment utilizes electrospinning technology to coat a nanofiber membrane of a humidity-sensitive material onto the peanut-shaped optical fiber. Compared to coating the fiber with a humidity-sensitive material, the nanofibers can be stably and evenly coated on the optical fiber surface, improving the measurement accuracy of the optical fiber temperature and humidity sensor. Furthermore, compared to a tapered optical fiber, the peanut-shaped optical fiber exhibits greater mechanical strength and is less prone to breakage.

[0043] Specifically, step a includes:

[0044] a1: Use a fiber fusion splicer to discharge the end of the single-mode fiber, melting the end of the single-mode fiber to form a spherical structure;

[0045] a2: Use the fusion mode of the optical fiber fusion splicer to fuse two single-mode optical fibers with spherical structures to form an optical fiber with a peanut-shaped structure.

[0046] Optionally, the spherical structures have a diameter of 200-250 μm.

[0047] Specifically, in step a1, two discharges are used to melt the end of the single-mode optical fiber to form a spherical structure, wherein the first discharge intensity is 150 bits and the discharge time is 150 ms, and the second discharge intensity is 300 bits and the discharge time is 4 s.

[0048] Specifically, in step a2, two spherical structures of single-mode optical fibers are placed next to each other, and the discharge intensity is set to 25 bits through the debugging mode of the fusion splicer, and the two spherical structures are fused to form a peanut-shaped structure.

[0049] It is worth noting that the peanut-shaped structure is not limited to two spherical structures, but can also be a spherical structure or multiple spherical structures connected in series. Figure 2 , Figure 2 is an optical microscope photograph of an optical fiber with a peanut-shaped structure provided by an embodiment of the present invention, such as Figure 2 As shown, in this embodiment, the peanut-shaped structure is formed by welding two spherical structures.

[0050] Furthermore, the nanofibers are ZnO nanofibers.

[0051] Further, the electrospinning method for preparing ZnO nanofibers is described in detail. Figure 3 , Figure 3 Schematic diagram of the electrospinning process provided by an embodiment of the present invention. In this embodiment, step b includes:

[0052] b1: prepare ZnO precursor solution;

[0053] In this embodiment, 1.0 g of Zn(NO3)2·6H2O was dissolved in 12 ml of N,N-dimethylformamide (DMF), and then 2 g of polyvinylpyrrolidone (PVP, Mn=1,300,000) was added to the above solution and continuously stirred to form a uniform ZnO precursor solution.

[0054] b2: Use a syringe to draw up the ZnO precursor solution. The syringe is mounted on the propulsion device of the electrospinning machine. The distance between the syringe and the grounded metal plate is 15-18 cm. Tin foil is placed on the metal plate to collect the nanofibers.

[0055] In this embodiment, a metal plate serves as a grounded target.

[0056] b3: Align the syringe with the tinfoil and perform electrospinning, where the electric field strength is 18 kV;

[0057] b4: The nanofibers collected from the tinfoil were annealed to obtain disordered ZnO nanofibers, wherein the annealing temperature was 500°C, the annealing time was 3 h, and the annealing heating rate was 1°C / min -1 .

[0058] See Figure 4 , Figure 4 This is a scanning electron microscope photo of the nanofibers provided by an embodiment of the present invention. As shown in the figure, in this embodiment, the ZnO nanofibers are intertwined and overlapped with each other, and most of the fibers are straight.

[0059] Optionally, in other embodiments, a mixed solution of polyvinyl alcohol (PVA) and zinc oxide (ZnO) can also be selected as the ZnO precursor solution. Specifically, the prepared PVA solution with a concentration of 8% and the ZnO solution with a concentration of 0.1 mg / ml are mixed in a ratio of 5:1, and stirred for one hour using a magnetic stirrer until uniform to prepare a PVA / ZnO mixed solution. The prepared PVA / ZnO mixed solution is sprayed onto tin foil using electrospinning technology to prepare PVA / ZnO mixed fibers, which can be directly coated on an optical fiber with a peanut-shaped structure through step c without the need for annealing.

[0060] Furthermore, step c includes: placing the optical fiber with a peanut-shaped structure on the ZnO nanofiber, and rotating the optical fiber with a peanut-shaped structure so that the ZnO nanofiber is coated thereon to form a nanofiber membrane, thereby obtaining a peanut-shaped optical fiber humidity sensor.

[0061] Optionally, place the prepared ZnO nanofiber on the operating table, take the optical fiber with a peanut-shaped structure, pinch both ends of the optical fiber with both hands, stick the optical fiber to the ZnO nanofiber, and tightly wrap the ZnO nanofiber around the optical fiber by rotating in the same direction.

[0062] It is worth noting that the thickness of the nanofiber membrane can be controlled by controlling the number of rotations of the optical fiber with a peanut-shaped structure to form a nanofiber membrane with a specific thickness, which is also the sensing membrane of the peanut-shaped optical fiber humidity sensor.

[0063] See Figure 5 , Figure 5 This is a scanning electron microscope photo of a peanut-shaped optical fiber coated with a nanofiber membrane provided by an embodiment of the present invention. As can be seen from the figure, ZnO nanofibers are tightly wrapped around the surface of the optical fiber, forming a nanofiber membrane of a certain thickness.

[0064] The method for preparing the peanut-shaped optical fiber humidity sensor of this embodiment first prepares nanofibers, and then winds the annealed nanofibers on the optical fiber to form a nanofiber membrane. This can avoid the problem of directly spraying the nanofibers on the optical fiber through electrospinning to form the nanofiber membrane, and then annealing the optical fiber and the nanofibers together, which causes the optical fiber to become brittle and easy to break. Moreover, by manual winding, the nanofiber membrane can be quickly and evenly produced on the optical fiber, and the thickness of the nanofiber membrane can be perfectly controlled. Compared with the traditional automatic roller winding method, which is tighter and more uniform, this manual winding method allows the nanofibers to be fixed on most structures.

[0065] Furthermore, this embodiment also provides a peanut-shaped optical fiber humidity sensor, comprising an optical fiber with a peanut-shaped structure and a nanofiber of a sensitive material coated thereon, wherein the peanut-shaped optical fiber humidity sensor of this embodiment is prepared using the preparation method described in the above embodiment.

[0066] The peanut-shaped optical fiber humidity sensor of this embodiment is easy to manufacture and can be prepared using only ordinary single-mode optical fiber at a low cost.

[0067] It should be noted that, in this document, the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the article or device comprising the element. "Connected" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The orientation or positional relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0068] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a peanut-shaped optical fiber humidity sensor, characterized in that: include: a: Optical fiber with a peanut-shaped structure is prepared using single-mode optical fiber; b: preparing nanofibers of a moisture-sensitive material by electrospinning, and subjecting the nanofibers to an annealing treatment; wherein the nanofibers are ZnO nanofibers; c: coating the annealed nanofibers on the optical fiber with a peanut-shaped structure to form a nanofiber membrane, so as to obtain a peanut-shaped optical fiber humidity sensor; Wherein, step b comprises: b1: prepare ZnO precursor solution; b2: Use a syringe to absorb the ZnO precursor solution, and install the syringe on the propulsion device of the electrospinning machine. The distance between the syringe and the grounded metal plate is 15-18 cm. Tin foil is placed on the metal plate to collect nanofibers; b3: Aim the syringe at the tin foil to perform electrospinning, where the electric field strength is 18KV; b4: The nanofibers collected from the tin foil were annealed to obtain disordered ZnO nanofibers, wherein the annealing temperature was 500°C, the annealing time was 3h, and the annealing heating rate was 1°C / min -1 ; Step c includes: placing the optical fiber with a peanut-shaped structure on the ZnO nanofiber, and rotating the optical fiber with a peanut-shaped structure so that the ZnO nanofiber is coated thereon to form a nanofiber membrane, so as to obtain a peanut-shaped optical fiber humidity sensor.

2. The method according to claim 1, characterized in that Step a includes: a1: using a fiber fusion splicer to discharge the end of the single-mode optical fiber, so that the end of the single-mode optical fiber is melted to form a spherical structure; a2: Using the fusion mode of the optical fiber fusion splicer, two single-mode optical fibers with spherical structures are fused to form an optical fiber with a peanut-shaped structure.

3. The method according to claim 2, characterized in that The diameter of the spherical structure is 200-250 μm.

4. The method according to claim 2, characterized in that: In step a1, two discharges are used to melt the end of the single-mode optical fiber to form a spherical structure, wherein the first discharge intensity is 150 bits and the discharge time is 150 ms, and the second discharge intensity is 300 bits and the discharge time is 4 s.

5. The method according to claim 2, characterized in that: In step a2, two spherical structures of the single-mode optical fiber are placed next to each other, and the discharge intensity is set to 25 bits through the debugging mode of the fusion splicer, and the two spherical structures are fused to form a peanut-shaped structure.

6. A peanut-shaped optical fiber humidity sensor, characterized in that: It comprises an optical fiber with a peanut-shaped structure and a nanofiber membrane of a moisture-sensitive material coated thereon, wherein the peanut-shaped optical fiber humidity sensor is prepared by the preparation method according to any one of claims 1-5.

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