Plasma modification device for generating fluorescent color developing film and control method thereof

Abstract

The application discloses a kind of plasma modification device and control method for generating fluorescent color film, including DBD reactor, gas path system, plasma excitation source;The gas path system includes parallel working gas gas path, reaction medium gas path and fluorescent agent gas path;Reaction medium gas path is inputted into mixed gas tank by flowmeter, anti-suck bottle and gas washing bottle;Fluorescent agent gas path is inputted into mixed gas tank by flowmeter, suck bottle and atomization bottle;Three-way gas in mixed gas tank is mixed and then passed into DBD reactor to modify the surface of object;During modification process, the flow of working gas gas path, reaction medium gas path and fluorescent agent gas path is controlled to generate fluorescent color film.The application prepares fluorescent film that can be clearly seen under ultraviolet light, and film thickness can be directly observed and modification effect can be judged by the brightness of fluorescent film.

Description

Technical Field

[0001] This invention relates to the field of plasma technology, and more specifically to a plasma modification device for generating fluorescent color-developing thin films and its control method. Background Technology

[0002] With the rapid development of low-temperature plasma technology, plasma has been widely used in the surface modification of insulating materials. By modifying the material surface through plasma, the physical and chemical (surface roughness, wettability, etc.), mechanical (tensile strength, wear resistance, etc.), and electrical (conductivity, flashover voltage, etc.) properties of insulating materials can be effectively improved.

[0003] Materials with good insulation properties used in electrical equipment, especially electrical insulating materials such as polymethyl methacrylate (PMMA), epoxy resin (ER), silicone rubber (SiR) and some polymers, need to maintain good performance under multiple challenges such as harsh environments, concentrated fields, and overvoltage flashover. Therefore, improving the hydrophobic and electrical insulation properties of insulating surfaces has become a research hotspot in the past decade.

[0004] However, the thin films formed after plasma treatment cannot always be clearly observed by the experimenter, especially when the color of the thin film is very close to the color of the treated material itself, making it even more difficult to effectively observe and judge the uniformity of the thin film.

[0005] Researchers have proposed several effective methods to determine the thickness and uniformity of thin films: in "The Influence of Solvents on the Morphology of Metal Thin Films on PMMA Substrates", Xue Xiuli's team used optical microscopy to observe the changes in the surface morphology of thin films; in "Preparation of Nano-TiO2 Thin Films and AFM Observation of Their Surface Morphology", Yu Honghua's team used atomic force microscopy (AFM) to obtain the microstructure of the thin films; in addition, calculating the water contact angle (WCA) between water droplets and the material surface can also be used to evaluate the quality of film formation, but most detection techniques are costly, complex to operate, cannot be measured during plasma processing, and are difficult to obtain the modification effect on large-area material surfaces.

[0006] The testing equipment (optical microscope, SEM, AFM) is too complex and expensive, making it difficult to obtain in experiments, which limits the dissemination of this microscopic analysis method. The detection range of these methods is limited and cannot meet the needs of large materials approaching the meter scale. Multi-point sampling and testing of large-area materials is not only time-consuming, but some tests can also damage the material itself. Furthermore, these methods are all offline evaluation methods, meaning that the material can only be tested after plasma treatment, but they cannot be used during plasma treatment, which limits the online diagnosis and real-time control of plasma thin film deposition. Summary of the Invention

[0007] 1. The technical problem to be solved:

[0008] To address the aforementioned technical problems, this invention provides a plasma modification device and its control method for generating fluorescent color-developing thin films. The device produces fluorescent thin films that are clearly visible under ultraviolet light. The film thickness can be directly observed and the modification effect can be judged by the brightness of the fluorescent thin film, providing the possibility for further online evaluation of the modification effect and uniformity of plasma treatment.

[0009] 2. Technical Solution:

[0010] A plasma modification device and its control method for generating fluorescent color-developing thin films are characterized by comprising a DBD reactor, a gas path system, and a plasma excitation source; the gas path system includes a working gas path, a reaction medium gas path, and a fluorescent agent gas path connected in parallel; the inlets of the working gas path, the reaction medium gas path, and the fluorescent agent gas path are all connected to the working gas cylinder pipeline.

[0011] The working gas path connects the working gas in the gas cylinder to the mixing box through a working gas flow meter;

[0012] The reaction medium gas path is connected in sequence through a reaction medium flow meter, a reaction medium anti-backflow bottle, and a reaction medium washing bottle to input the reaction medium gas into the mixing box; the liquid in the reaction medium washing bottle is hexamethyldisiloxane;

[0013] The fluorescent agent gas path is connected in sequence by a fluorescent agent flow meter, a fluorescent agent anti-backflow bottle, and a fluorescent atomizing bottle, which input the atomized fluorescent agent gas into the mixing box; the fluorescent atomizing bottle is supplied with working gas through its inlet, and the ultrasonic atomizer in the fluorescent agent atomizing bottle atomizes the fluorescent agent and discharges it from its outlet.

[0014] The three gases introduced into the mixing chamber are mixed and then introduced into the main gas path of the DBD reactor; the plasma excitation source drives the DBD reactor to discharge and modify the surface of the object.

[0015] During the modification process, the flow rates of the working gas, reaction medium, and fluorescent agent are controlled to generate a fluorescent color-developing film. Specifically, the control includes: controlling the flow rate of the working gas Ar to 1~2 L / min using a working gas flow meter; controlling the rate of medium blowing in to 10~15 mL / min using a reaction medium flow meter; and controlling the rate of fluorescent agent blowing in to 200~300 mL / min using a fluorescent agent flow meter.

[0016] Furthermore, the fluorescent agent in the fluorescent atomizing bottle is 4,4'-diamino-2,2'-stilbene disulfonic acid.

[0017] Furthermore, it also includes two plastic tee connectors; the first plastic tee connector divides the gas output from the gas cylinder into two paths: a fluorescent agent gas path, a working gas path, and a combined reaction medium gas path; the second plastic tee connector separates the working gas path and the combined reaction medium gas path.

[0018] Furthermore, the gas in the gas cylinder is Ar gas with a purity of 99.999%.

[0019] Furthermore, the diameter of the atomized fluorescent agent is 1~5μm after being atomized by an ultrasonic atomizer.

[0020] Furthermore, the DBD reactor includes a high-voltage electrode and a ground electrode; both the high-voltage electrode and the ground electrode are flat metal plates; the discharge gap between the high-voltage electrode and the ground electrode is 2-3 mm; a blocking medium is provided on the surface of both the high-voltage electrode and the ground electrode; the gas output from the main gas path passes through the discharge gap.

[0021] Furthermore, the plasma-treated material surface was irradiated with ultraviolet light with a wavelength of 10nm to 400nm, causing the plasma-assisted fluorescent film to exhibit blue-green fluorescence.

[0022] 3. Beneficial effects:

[0023] (1) The present invention provides a plasma modification device for generating fluorescent color-developing films, which combines fluorescent color-developing technology with plasma material modification technology. It prepares fluorescent films that are clearly visible under ultraviolet light. The film thickness can be directly observed by the brightness of the fluorescent film, and the modification effect can be judged. This provides the possibility for further online evaluation of the modification effect and uniformity of plasma treatment.

[0024] (2) The working gas path, reaction medium path and fluorescent agent path connected in parallel in this invention respectively introduce the working gas, reaction medium and fluorescent agent into the mixing box. By setting the flow rate of each gas path flow meter, the concentration of fluorescent agent and reaction medium entering the reaction space is controlled. Combined with the working gas argon, it helps to construct the fluorescent color-developing film.

[0025] (3) The fluorescent agent gas path in this invention is equipped with an ultrasonic atomizer to atomize the fluorescent agent with a low saturated vapor pressure. The atomized particles have a diameter of 1~5μm, which ensures that they can be evenly distributed and does not affect plasma discharge and thin film deposition.

[0026] (4) In this invention, both the reaction medium gas path and the fluorescent agent gas path are equipped with anti-backflow bottles, which can effectively avoid backflow problems caused by flow rate mismatch or gas pressure imbalance of the reaction medium or fluorescent agent. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the connection of a plasma modification device with a fluorescent color-developing film according to the present invention;

[0028] Figure 2 The graph shows the effect of the amount of fluorescent agent added on the discharge current and spectrum of the DBD reactor in this device.

[0029] Figure 3 This is a schematic diagram of the DBD reactor in this invention;

[0030] Figure 4 This is a comparison diagram of a conventional thin film and a fluorescent thin film generated using the present invention in a specific embodiment. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings.

[0032] As attached Figure 1 As shown, a plasma modification device for generating fluorescent color-developing thin films and its control method are characterized by comprising a DBD reactor 12, a gas path system, and a plasma excitation source 13; the gas path system includes a working gas path, a reaction medium gas path, and a fluorescent agent gas path connected in parallel; the inlets of the working gas path, the reaction medium gas path, and the fluorescent agent gas path are all connected to the working gas cylinder 1 pipeline.

[0033] The working gas path connects the working gas in the gas cylinder to the mixing box 11 through the working gas flow meter 3;

[0034] The reaction medium gas path is connected in sequence through a reaction medium flow meter 4, a reaction medium anti-backflow bottle 6, and a reaction medium washing bottle 7 to input the reaction medium gas into the mixing box; the liquid in the reaction medium washing bottle is hexamethyldisiloxane;

[0035] The fluorescent agent gas path is connected in sequence by a fluorescent agent flow meter 5, a fluorescent agent anti-backflow bottle 8, and a fluorescent atomizing bottle 9 via a pipe 14, which inputs the atomized fluorescent agent gas into the mixing box; the working gas is introduced into the inlet of the fluorescent atomizing bottle, and the ultrasonic atomizer 10 in the fluorescent agent atomizing bottle atomizes the fluorescent agent and discharges it from its outlet.

[0036] The three gases introduced into the mixing chamber are mixed and then introduced into the main gas path of the DBD reactor; the plasma excitation source drives the DBD reactor to discharge and modify the surface of the object.

[0037] During the modification process, the flow rates of the working gas, reaction medium, and fluorescent agent are controlled to generate a fluorescent color-developing film. Specifically, the control includes: controlling the flow rate of the working gas Ar to 1~2 L / min using a working gas flow meter; controlling the rate of medium blowing in to 10~15 mL / min using a reaction medium flow meter; and controlling the rate of fluorescent agent blowing in to 200~300 mL / min using a fluorescent agent flow meter.

[0038] Furthermore, the fluorescent agent in the fluorescent atomizing bottle is 4,4'-diamino-2,2'-stilbene disulfonic acid.

[0039] Furthermore, it also includes two plastic tee connectors; the first plastic tee connector 15 divides the gas output from the gas cylinder into two paths: a fluorescent agent gas path, a working gas path, and a combined reaction medium gas path; the second plastic tee connector 16 separates the working gas path and the combined reaction medium gas path.

[0040] Furthermore, the gas in the gas cylinder is Ar gas with a purity of 99.999%.

[0041] Furthermore, the diameter of the atomized fluorescent agent is 1~5μm after being atomized by an ultrasonic atomizer.

[0042] Furthermore, the DBD reactor includes a high-voltage electrode and a ground electrode; both the high-voltage electrode and the ground electrode are flat metal plates; the discharge gap between the high-voltage electrode and the ground electrode is 2-3 mm; a blocking medium is provided on the surface of both the high-voltage electrode and the ground electrode; the gas output from the main gas path passes through the discharge gap.

[0043] Furthermore, the plasma-treated material surface was irradiated with ultraviolet light with a wavelength of 10nm to 400nm, causing the plasma-assisted fluorescent film to exhibit blue-green fluorescence.

[0044] Principle of this invention:

[0045] In this invention, a silicon-containing medium, hexamethyldisiloxane (HMDSO), is added to the reaction medium gas path. After plasma activation, it forms a Si-containing thin film with high fragmentation and high film-forming efficiency, making it an excellent choice for forming hydrophobic surfaces. Because HMDSO contains two silicon atoms, each with three methyl groups and sharing one oxygen atom, while SiCl4 consists of a silicon atom surrounded by four chlorine atoms, forming a tetrahedral spatial structure with symmetry, it is more stable than HMDSO. During plasma modification, it is less likely to collide with high-energy electrons and excited Ar atoms, generating free radicals. Therefore, atmospheric pressure plasma modification containing HMDSO yields superior results in surface modification of materials.

[0046] The fluorescent agent gas path in this invention contains the organic fluorescent agent 4,4'-diamino-2,2'-stilbene disulfonic acid (C 14 H 14 N₂O₆S₂ (DSD), a fluorescent agent, is a complex organic compound containing multiple conjugated fluorescent groups. Compared to other fluorescent agents, DSD exhibits higher mechanical properties and thermal stability, and demonstrates better fluorescence under ultraviolet light irradiation. Due to the extremely low saturated vapor pressure of DSD, this invention employs an ultrasonic atomizer-assisted atomization method, equipped with a fluorescent agent flow meter to control the concentration of the added fluorescent agent. The ultrasonic atomizer atomizes the fluorescent colorimetric agent into tiny droplets of 1-5 μm, which are then carried into the plasma discharge space by the working gas, ensuring uniform distribution and not affecting plasma discharge and thin film deposition. (See attached...) Figure 2 The figure shown is a graph illustrating the effect of the amount of fluorescent agent added on the discharge current and spectrum of the DBD reactor, obtained through experiments.

[0047] As attached Figure 1 The diagram shows the gas output from the gas cylinder splitting into two via a first plastic tee connector. One path leads to a second plastic tee connector, which then splits the gas again. One path connects to the working gas flow meter, while the other connects to the reaction medium flow meter, carrying the HMDSO reaction medium from the gas washing bottle into the mixing chamber via bubbling. The other path from the first plastic tee connector connects to the fluorescent agent flow meter, carrying out small droplets of fluorescent agent in the fluorescent agent atomizing bottle. Anti-backflow bottles are used before both the reaction gas washing bottle and the fluorescent agent atomizing bottle to prevent backflow of the reaction medium or fluorescent agent due to flow rate mismatch or pressure imbalance. In the diagram, 2 is a pressure reducing valve, and 17 is a UV lamp.

[0048] All three gas path structures are connected to the DBD reactor as its main gas path. High-purity (99.999%) Ar is used as the working gas, and HMDSO, a typical siloxane used for hydrophobic modification of materials, is used as a precursor and delivered to the DBD discharge region via bubbling. A controllable ultrasonic atomizer is immersed in the liquid fluorescent agent, which can atomize the fluorescent agent into tiny droplets of 1-5 μm at room temperature. Working gas Ar (1~2 L / min), medium A HMDSO (10~15 mL / min), and atomizing fluorescent agent C 14 H 14 N2O6S2 (200~300 mL / min) was thoroughly mixed at a flow rate controlled by a flow meter.

[0049] As attached Figure 3The diagram shows the structure of the DBD reactor in this invention. Typically, a pair of 15mm wide and 200mm long metal conductors are used as high-voltage electrodes, distributed on both sides of the main gas path. A flat metal plate is used as the ground electrode, fixed below the reactor, with a discharge gap of 2-3mm. The reactor uses a double-barrier structure: a 2mm thick resin barrier on the high-voltage electrode and a 3mm thick glass plate barrier on the ground electrode.

[0050] The DBD reactor discharges under the action of a plasma excitation source, generating plasma and forming a thin film containing a fluorescent agent on the surface of the insulating material, such as... Figure 4 As shown. Figure 4 (a) is an image of the film treated by a conventional DBD reactor under normal light; (b) is an image of the film treated by a conventional DBD reactor under ultraviolet light; (c) and (d) are images of the film treated by the present invention under normal light and ultraviolet light, respectively. It can be clearly seen from the figures that although the deposited film on the surface of the insulating material is still unclear and invisible under natural light, the plasma-assisted fluorescent film exhibits blue-green fluorescence on the surface of the material after plasma treatment by irradiating the surface with ultraviolet light with a wavelength of 10nm to 400nm.

[0051] Although the present invention has been disclosed above with reference to preferred embodiments, these are not intended to limit the invention. Any person skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be defined by the scope of the claims of this application.

Claims

1. A plasma modification device for generating fluorescent color-developing thin films and its control method, characterized in that: It comprises a DBD reactor, a gas path system and a plasma excitation source; the gas path system comprises parallel working gas path, reaction medium path and fluorescent agent path; the gas inlets of the working gas path, reaction medium path and fluorescent agent path are connected with the gas bottle pipeline of working gas; The working gas path connects the working gas in the gas bottle to the gas mixing box through the working gas flow meter; The reaction medium path inputs the reaction medium gas into the gas mixing box through the reaction medium flow meter, reaction medium anti-suck bottle and reaction medium gas washing bottle connected by pipelines; the liquid in the reaction medium gas washing bottle is hexamethyldisiloxane; The fluorescent agent path inputs the gas containing atomized fluorescent agent into the gas mixing box through the fluorescent agent flow meter, fluorescent agent anti-suck bottle and fluorescent agent atomization bottle connected by pipelines; the inlet of the fluorescent agent atomization bottle is connected with working gas, and the ultrasonic atomizer in the fluorescent agent atomization bottle atomizes the fluorescent agent and discharges it from the outlet; The three gases input into the gas mixing box are mixed and then input into the main gas path of the DBD reactor; the plasma excitation source drives the DBD reactor to discharge to modify the surface of the object; During the modification process, the fluorescent color film is generated by controlling the flow of the working gas path, reaction medium path and fluorescent agent path; the specific control includes: controlling the flow rate of the working gas Ar through the working gas flow meter to be 1-2 L / min; controlling the blowing rate of the medium through the reaction medium flow meter to be 10-15 mL / min; and controlling the blowing rate of the fluorescent agent through the fluorescent agent flow meter to be 200-300 mL / min.

2. The apparatus for plasma modification for generating a fluorescent color developing film according to claim 1, wherein: The fluorescent agent in the fluorescent agent atomization bottle is 4,4'-diamino-2,2'-stilbene disulfonic acid.

3. The plasma modification device and its control method for generating fluorescent color-developing thin films according to claim 1, characterized in that: It also comprises two plastic tee joints; the first plastic tee joint divides the gas output from the gas bottle into two paths, i.e., the fluorescent agent path, the working gas path and the reaction medium path combined gas path; the second plastic tee joint separates the working gas path and the reaction medium path combined gas path.

4. The plasma modification device and its control method for generating fluorescent color-developing thin films according to claim 1, characterized in that: The gas in the gas bottle is Ar gas with a purity of 99.999%.

5. The apparatus for plasma modification for generating a fluorescent color developing film according to claim 1, wherein: The mist particle diameter of the atomized fluorescent agent is 1-5 μm through the ultrasonic atomizer.

6. The apparatus for plasma modification of a fluorescent color development film and the control method thereof according to claim 1, wherein: The DBD reactor comprises a high-voltage electrode and a ground electrode; both the high-voltage electrode and the ground electrode are flat metal plates; the discharge gap between the high-voltage electrode and the ground electrode is 2-3 mm; the surfaces of the high-voltage electrode and the ground electrode are provided with barrier medium; and the gas output from the main gas path is connected to the discharge gap.

7. The apparatus for plasma modification of a fluorescent color development film and the control method thereof according to claim 1, wherein: The surface of the material after plasma treatment is irradiated with ultraviolet light with a wavelength of 10 nm-400 nm, so that the plasma-assisted fluorescent film presents blue-green fluorescence.

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