Optical fiber probe and preparation method of hydrophobic membrane applied to optical fiber probe

Abstract

The invention discloses an optical fiber probe and a preparation method of a hydrophobic membrane applied to the optical fiber probe, and relates to the technical field of optical fiber probe hydrophobic membranes. The problem that water and kerosene cannot be distinguished due to the fact that an existing optical fiber probe is stained with water in oil-water two-phase flow is solved. A preparation method of a hydrophobic membrane applied to an optical fiber probe comprises the following steps: preparing the optical fiber probe, and removing a coating layer and a cladding layer of the optical fiber probe; preparing a hydrophobic membrane solution; performing cold compress treatment on the optical fiber probe; and soaking the optical fiber probe in the hydrophobic membrane solution for 10 minutes to complete hydrophobic treatment of the optical fiber probe. The method is also suitable for experiments of the optical fiber probe hydrophobic membrane and the preparation method thereof.

Description

Technical Field

[0001] The invention relates to the technical field of hydrophobic films for optical fiber probes. Background Art

[0002] Two-phase flow is a two-phase coexisting flow body composed of a mixture of gas (or steam) and liquid, such as oil-water two-phase flow. It is widely present in power generation systems, nuclear reactors, foam columns, heat exchangers and submarine oil recovery wells. In oil-water two-phase flow, kerosene exists as a dispersed phase in the form of droplets, and water flows in the pipeline as a continuous phase. Two-phase flow parameters include the volume fraction, velocity, size, etc. of droplets. Accurate acquisition of two-phase flow parameters is of great significance for improving production structure and optimizing enterprise production dynamic characteristics.

[0003] Fiber optic probe sensing is a detection method that uses light reflection to measure two-phase flow parameters. The reflectivity of the light emitted by the fiber optic probe is different in the two media of oil and water, and the light intensity at the receiving end is also different. The photoelectric conversion circuit then outputs voltage signals of different sizes, and subsequent data processing is performed to obtain the measurement of the two-phase flow parameters. The main material of the fiber optic probe is silicon dioxide. Since its surface tension is greater than that of water, in the oil-water two-phase flow experiment, the fiber optic probe sensor will be stained with water when placed in the oil-water two-phase flow experimental device. The wettability of the fiber optic probe surface changes, making it impossible to distinguish between water and kerosene, which seriously affects the experimental results.

[0004] Patent document CN103521095A discloses a method for preparing a tubular ceramic membrane for oil-water separation, and provides a method for preparing a tubular ceramic membrane for oil-water separation, which is used to solve the technical problem that the filtration flux of ceramic membranes in the prior art is low when processing oil phase systems. However, the ceramic membrane has low transmittance and cannot be used in optical fiber probe measurement. Document number is patent document CN107349803A a super-hydrophobic polymer microporous membrane and its manufacturing method, which introduces a super-hydrophobic polymer microporous membrane for oil-water separation, but the material refractive index used in the method and the optical fiber material silica refractive index gap are large, and the material will affect its original optical fiber performance after being coated on the optical fiber probe, so that water and kerosene cannot be distinguished. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the existing optical fiber probe cannot distinguish water from kerosene in oil-water two-phase flow because it is stained with water.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] Solution 1: A method for preparing a hydrophobic film for use in an optical fiber probe, comprising the following steps:

[0008] S1, preparing an optical fiber probe, and removing a coating layer and a cladding layer of the optical fiber probe;

[0009] S2, preparing a hydrophobic membrane solution;

[0010] S3, performing a cold compress treatment on the optical fiber probe described in S1; placing the optical fiber probe in the prepared hydrophobic membrane solution and soaking it for 10 minutes to complete the hydrophobic treatment of the optical fiber probe;

[0011] Furthermore, a preferred embodiment is provided, in which a silica single-mode optical fiber is used as the optical fiber probe in S1.

[0012] Furthermore, a preferred embodiment is provided, wherein the core diameter of the silica single-mode optical fiber is 9 μm, the outer diameter of the cladding is 125 μm, the refractive index of the cladding is 1.455, and the outer diameter of the coating is 250 μm.

[0013] Furthermore, a preferred embodiment is provided, in which a fiber optic stripping pliers is used to remove the coating layer of the fiber optic probe.

[0014] Furthermore, a preferred embodiment is provided, in which a hydrofluoric acid solution is used to remove the cladding of the optical fiber probe in S1.

[0015] Furthermore, a preferred embodiment is provided, wherein the hydrophobic membrane solution comprises polystyrene, polydimethylsiloxane, polyacrylate and ethyl acetate.

[0016] Furthermore, a preferred embodiment is provided, in which the method for preparing the hydrophobic membrane solution is as follows: at room temperature, 10 g of polystyrene particles, 10 mL of polydimethylsiloxane analytical grade reagent, and 2 g of polyacrylate are added to 100 mL of ethyl acetate analytical grade solution, and stirred thoroughly to dissolve them, thereby completing the preparation of the hydrophobic membrane solution.

[0017] Furthermore, a preferred embodiment is provided, in which the refractive index of the hydrophobic film is made the same as the refractive index of the optical fiber probe by adjusting the refractive index of polystyrene and polydimethylsiloxane.

[0018] Furthermore, a preferred embodiment is provided, wherein the refractive index of the hydrophobic film is 1.45.

[0019] Solution 2: A fiber optic probe, the surface of which is covered with a hydrophobic film, and the probe is prepared by any method described in Solution 1.

[0020] The present invention is beneficial in that:

[0021] The invention has the advantages of simple operation, controllable preparation process, low cost, good repeatability and good safety, and non-toxic or low-toxic chemicals are used in the whole experimental process.

[0022] The present invention uses a mixture of polystyrene and polydimethylsiloxane to prepare a hydrophobic film with good light transmittance. By reasonably controlling the configuration ratio of the two raw materials, the refractive index of the hydrophobic film is very close to that of the optical fiber probe itself, without affecting the optical properties of the optical fiber probe itself.

[0023] The hydrophobic film prepared by polystyrene, polydimethylsiloxane and polydimethylsiloxane has strong adsorption and corrosion resistance, is not easy to fall off when coated on the optical fiber probe, and will not dissolve in a two-phase flow pipeline composed of water and kerosene.

[0024] The hydrophobic membrane of the present invention has good light transmittance, and its refractive index is very close to that of the optical fiber probe itself, so it has a good distinguishing effect on oil-water two-phase flow, and the experimental process is simple and the experimental safety is high.

[0025] The invention is also applicable to experiments on hydrophobic membranes of optical fiber probes and preparation methods thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a preparation flow chart of a method for preparing a hydrophobic film applied to an optical fiber probe according to the first embodiment.

[0027] Figure 2 This is a schematic diagram of a method for preparing a hydrophobic film applied to an optical fiber probe according to the first embodiment.

[0028] Figure 3 This is a detection voltage curve diagram of the uncoated optical fiber probe of the present invention.

[0029] Figure 4 This is a detection voltage curve diagram of the optical fiber probe after coating of the present invention.

[0030] In the figure, there is a silica single-mode optical fiber core 1, a cladding 2, and a coated silica single-mode optical fiber core 3. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the implementation methods of the present application clearer, the technical solutions in the implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the implementation methods of the present application. Obviously, the described implementation methods are only part of the implementation methods of the present application, not all of the implementation methods.

[0032] Implementation method 1, see Figures 1 to 4 This embodiment provides a method for preparing a hydrophobic film for use in an optical fiber probe, the method comprising the following steps:

[0033] S1, preparing an optical fiber probe, removing the coating layer and cladding 2 of the optical fiber probe;

[0034] S2, preparing a hydrophobic membrane solution;

[0035] S3, performing a cold compress treatment on the optical fiber probe described in S1; placing the optical fiber probe in the prepared hydrophobic membrane solution and soaking it for 10 minutes to complete the hydrophobic treatment of the optical fiber probe.

[0036] Embodiment 2: This embodiment further limits the method for preparing a hydrophobic film applied to an optical fiber probe described in Embodiment 1. In S1, a single-mode silica optical fiber is used as the optical fiber probe.

[0037] Embodiment 3. This embodiment further limits the method for preparing the hydrophobic film for optical fiber probe described in embodiment 2. The outer diameter of the silica single-mode optical fiber core is 9 μm, the outer diameter of the cladding 2 is 125 μm, the refractive index of the cladding 2 is 1.455, and the outer diameter of the coating layer is 250 μm.

[0038] Embodiment 4: This embodiment further limits the method for preparing a hydrophobic film applied to an optical fiber probe described in Embodiment 1, and uses an optical fiber stripper to remove the coating layer of the optical fiber probe.

[0039] Embodiment 5: This embodiment further limits the method for preparing a hydrophobic film applied to an optical fiber probe described in Embodiment 1. In S1, a hydrofluoric acid solution is used to remove the cladding 2 of the optical fiber probe.

[0040] Embodiment 6: This embodiment further limits the method for preparing a hydrophobic film applied to an optical fiber probe described in Embodiment 1, wherein the hydrophobic film solution includes polystyrene, polydimethylsiloxane, polyacrylate and ethyl acetate.

[0041] Embodiment 7. This embodiment further limits the method for preparing the hydrophobic film for optical fiber probe described in embodiment 4. The method for preparing the hydrophobic membrane solution is as follows: at room temperature, 10 g of polystyrene particles, 10 mL of polydimethylsiloxane analytical grade reagent, and 2 g of polyacrylate are added to 100 mL of ethyl acetate analytical grade solution, stirred thoroughly to dissolve, and the hydrophobic membrane solution is prepared.

[0042] Embodiment 8: This embodiment further limits the method for preparing the hydrophobic film applied to the optical fiber probe described in embodiment 4, by adjusting the refractive index of polystyrene and polydimethylsiloxane to make the refractive index of the hydrophobic film the same as that of the optical fiber probe.

[0043] Embodiment 9: This embodiment further limits the method for preparing the hydrophobic film applied to the optical fiber probe described in embodiment 8, and the refractive index of the hydrophobic film is 1.45.

[0044] The above implementation is described in detail below. S1 specifically includes the following steps:

[0045] S1.1. Take a section of single-mode optical fiber patch cord, cut off the connector at one end, remove the protective cover about 5 cm from the tail end of the optical fiber, and then use wire strippers to remove the coating layer of the optical fiber.

[0046] S1.2. When the fiber optic probe is used for two-phase flow measurement, the end of the port is required to be smooth. A fiber optic cutter should be used to cut off part of the end fiber, and the end of the fiber optic cable should be left with a length of about 2 cm. Then, a fiber optic cleaning cloth dipped in ethanol and acetone should be used to wipe repeatedly in the same direction to ensure that the coating on the fiber optic probe is completely removed.

[0047] S1.3, then use hydrofluoric acid to corrode and remove part of the fiber cladding 2. Hydrofluoric acid is highly irritating and corrosive. Double-layer acid-proof rubber gloves, protective glasses and medical masks are required during the experiment. The laboratory must be well ventilated during the experiment. Use a measuring cup to measure 100mL of 30% hydrofluoric acid solution and put it into a plastic beaker, and put the optical fiber probe into the hydrofluoric acid solution.

[0048] S1.4. Wait for 30 minutes. After the coating layer of the optical fiber probe is completely removed, take out the probe, put it in a beaker of deionized water, and then put it into an ultrasonic cleaner. Oscillate it for 3 minutes, and then put it in a drying oven to dry it to remove moisture on the surface and ensure the cleanliness of the optical fiber end face. Any residual dirt will affect the effect of the subsequent hydrophobic treatment.

[0049] S2. Prepare a hydrophobic membrane solution.

[0050] S2.1. First, use a measuring cup to measure 100 mL of analytical pure ethyl acetate solution into a beaker. High concentration ethyl acetate has a pungent smell similar to nail polish, so you need to wear a mask during the preparation process. Then use an electronic balance to weigh 10 g of polystyrene, add it to the ethyl acetate solution, and use a glass rod to stir thoroughly to completely dissolve the polystyrene.

[0051] S2.2. Use a measuring cup to measure 10 mL of analytical grade polydimethylsiloxane reagent, then pour it into the polystyrene solution and stir with a glass rod to dissolve it.

[0052] S2.3. Use an electronic balance to weigh 2g of polymethyl acrylate and add it to the above solution to fully dissolve it. The hydrophobic film is now ready for coating.

[0053] S3. The optical fiber probe is coated with a hydrophobic film.

[0054] S3.1. When coating, first fix one end of the optical fiber, and then vertically place the other end of the optical fiber into a beaker containing hydrophobic film solution and soak for 30 minutes. During the static process, the beaker needs to be sealed with tin foil.

[0055] S3.2. After the soaking time is over, the optical fiber probe 3 coated with the hydrophobic film is placed in a drying oven for drying or placed in the air for 30 minutes to dry naturally.

[0056] S3.3. After the hydrophobic film is naturally dried, the preparation is completed.

[0057] Next, the hydrophobic effect of the hydrophobic film on the optical fiber probe coated by the above method is verified.

[0058] S4.1. Take a beaker and pour 50 mL of water and 50 mL of kerosene into it. Water and kerosene are incompatible with each other, and the density of water is greater than that of kerosene. In the beaker, the water is at the bottom layer and the kerosene is at the top layer.

[0059] S4.2. Take a fiber optic probe without hydrophobic film, connect one end to the two-phase flow measurement device, and put the other end into water and kerosene. Collect the real-time voltage through the acquisition card and draw the voltage-time curve as shown in Figure 3 shown.

[0060] At 0-1.3s, the voltage was about 1V, and the probe was in the upper layer of kerosene; at 1.3s-2.5s, the voltage was about 10V, and the probe was in the water at the bottom of the beaker; after 2.5s, the fiber optic probe was put from water into kerosene. At this time, the fiber optic probe was stained with water, and the surface wettability changed, so the voltage could no longer be measured normally.

[0061] S4.3. Take a fiber optic probe coated with a hydrophobic film, connect one end to the two-phase flow measurement device, and put the other end into water and kerosene. Collect the real-time voltage through the acquisition card and draw the voltage-time curve as shown in Figure 4 shown.

[0062] At 0-1.2s, the voltage was about 1V, and the probe was in the upper kerosene; at 1.2s-2.6s, the voltage was about 10V, and the probe was in the water at the bottom of the beaker; at 2.5s-3.8s, the voltage was about 1V, and the probe was in the upper kerosene; after 3.8s, the voltage was about 10V, and the probe was in the water at the bottom of the beaker. It can be seen that during the entire experiment, the surface of the optical fiber probe was not stained with water, and the hydrophobic effect was good.

[0063] Embodiment 10: This embodiment proposes an optical fiber probe, the surface of which is covered with a hydrophobic film. The probe is prepared by the method described in any one of embodiments 1 to 9.

[0064] The hydrophobic effect of the hydrophobic film described in this embodiment is closely related to the hydrophobic angle. The wetting ability of a liquid on a solid is closely related to the contact angle formed by the liquid on the solid surface, which is the result of the surface tension balance of the liquid at the solid-liquid-gas interface on the material surface.

[0065] According to Young's equation, the contact angle θ of a liquid on a solid surface can be calculated by the following formula:

[0066]

[0067] where σ(sg) is the surface tension of the solid;

[0068] σ(lg) is the surface tension of the liquid;

[0069] Φ is the interaction factor, which is related to the surface properties of the liquid phase and the solid phase;

[0070] When the distances between various molecules are close and the polarities between the solid phase and the liquid phase are close, Φ approaches 1. For the convenience of qualitative analysis, assume Φ = 1 to discuss which materials have hydrophobic properties. When the surface tension of the solid is greater than the surface tension of the liquid, i.e., σ(sg) >= σ(lg), from the above formula, it can be seen that 0 < cosθ <= 1. At this time, the liquid wets the solid surface. When θ = 0°, the liquid completely spreads on the solid surface, that is, spreading occurs and the solid surface is completely wetted, and the solid has the maximum wettability; when the surface tension of the solid is less than the surface tension of the liquid, -1 <= cosθ < 0. At this time, 90° < θ <= 180°, and the liquid has a tendency to separate from the solid, and the liquid does not wet the solid. If σ(sg) << σ(lg), then θ = 180°, and at this time the solid is completely not wetted; when θ = 90°, the solid is in the critical state of being liquid-philic and liquid-phobic. Generally, it is considered that θ ≥ 140° indicates that the solid has superhydrophobic properties for this liquid. Therefore, the contact angle is a standard for measuring the hydrophobic performance of the solid surface. Knowing the size of the contact angle can roughly measure the wetting degree. The smaller the contact angle, the better the wetting ability, and the larger the contact angle, the better the liquid-phobic performance.

[0071] At room temperature, the surface tension of water is 72.75 mN·m-1. To increase the hydrophobic angle, the ratio of the surface tension of the solid to the surface tension of water should be made as small as possible, that is, the surface tension of the solid material should be smaller than 72.75 mN·m-1, and the smaller the value, the larger the contact angle of water on this material and the less likely it is to wet the solid surface. The surface tension of polystyrene is 40.7 mN·m-1, and the surface tension of polydimethylsiloxane is 20.4 mN·m-1. Substituting into the above formula for calculation, the hydrophobic angle can reach 145°, showing a good hydrophobic effect.

[0072] Polyacrylate has adhesiveness and can enhance the adsorption of the hydrophobic film on the optical fiber probe. Adding it to the hydrophobic film solution can enhance the adsorption force of polystyrene and polydimethylsiloxane on the optical fiber probe, making the hydrophobic film not easy to fall off. Ethyl acetate is a solvent for polystyrene and polydimethylsiloxane.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0074] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a hydrophobic film for an optical fiber probe, characterized in that: The following steps are included: S1, preparing an optical fiber probe, and removing a coating layer and a cladding layer (2) of the optical fiber probe; S2, preparing a hydrophobic membrane solution; S3, performing cold compress treatment on the optical fiber probe described in S1; The optical fiber probe is placed in the hydrophobic membrane solution and immersed for 10 minutes to complete the hydrophobic treatment of the optical fiber probe.

2. The method for preparing a hydrophobic film for an optical fiber probe according to claim 1, characterized in that: In S1, silica single-mode optical fiber is used as the optical fiber probe.

3. The method for preparing a hydrophobic film for an optical fiber probe according to claim 2, characterized in that: The diameter of the silica single-mode optical fiber core (1) is 9 μm, the outer diameter of the cladding (2) is 125 μm, the refractive index of the cladding (2) is 1.455, and the outer diameter of the coating layer is 250 μm.

4. The method for preparing a hydrophobic film for an optical fiber probe according to claim 1, characterized in that: Use fiber optic strippers to remove the coating from the fiber optic probe.

5. The method for preparing a hydrophobic film for an optical fiber probe according to claim 1, characterized in that: In S1, a hydrofluoric acid solution is used to remove the cladding of the optical fiber probe (2).

6. The method for preparing a hydrophobic film for an optical fiber probe according to claim 1, characterized in that: The hydrophobic membrane solution includes polystyrene, polydimethylsiloxane, polyacrylate and ethyl acetate.

7. The method for preparing a hydrophobic film for an optical fiber probe according to claim 4, characterized in that: The method for preparing the hydrophobic membrane solution is as follows: at room temperature, 10 g of polystyrene particles, 10 mL of polydimethylsiloxane analytical grade reagent, and 2 g of polyacrylate are added to 100 mL of ethyl acetate analytical grade solution, and stirred sufficiently to dissolve the mixture, thereby completing the preparation of the hydrophobic membrane solution.

8. The method for preparing a hydrophobic film for an optical fiber probe according to claim 1, characterized in that: The refractive index of the hydrophobic film is made to be the same as that of the optical fiber probe by adjusting the refractive index of polystyrene and polydimethylsiloxane.

9. The method for preparing a hydrophobic film for an optical fiber probe according to claim 8, characterized in that: The refractive index of the hydrophobic film is 1.

45.

10. An optical fiber probe, the surface of which is covered with a hydrophobic film, characterized in that: The probe is prepared by the method according to any one of claims 1 to 9.

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