A method for manufacturing a micro water content monitoring sensor, a system thereof, and a method for using the same

Abstract

The application discloses a preparation method of a micro-water content monitoring sensor, a system thereof and a use method thereof, and belongs to the technical field of sensors. The preparation method comprises the following steps: mixing a compound containing a disulfide bond, nanoparticles and deionized water to obtain a nanoparticle solution; adding an anionic fluorocarbon surfactant into the nanoparticle solution, stirring to form an aqueous solution; spraying the aqueous solution on the surface of a friction material, drying, and then modifying the dried coating layer by using a fluorine-containing silane to obtain the micro-water content monitoring sensor. The sensor is assembled with an electrode material into a triboelectric sensor, and is assembled into a triboelectric sensor array according to different combination modes, so that the signal response of water content is realized, and the purpose of high-selectivity monitoring is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sensors, and particularly relates to a preparation method of a micro-water content monitoring sensor, a system thereof and a use method. BACKGROUND

[0002] In contemporary industrial production, lubricating oil is not only a lubricant for the operation of mechanical equipment, but also a characterization index of its health status. The quality and purity of lubricating oil are directly related to the operating efficiency and service life of the machinery. In particular, the content of liquid contaminants such as water in the lubricating oil is a key indicator for assessing the environmental impact on the equipment. Water in the lubricating oil can reduce the lubricating performance, cause corrosion and oxidation, reduce the cleanliness and performance of the oil, and lead to mechanical failure.

[0003] The commonly used lubricating oil water monitoring sensors at present mainly include methods based on capacitance, resistance and optics, which can detect at least as low as 200 ppm. The capacitance sensor measures the water content in the oil based on the principle that the change of water content in the oil will cause the change of dielectric constant. The optical sensor uses the distortion effect of light passing through the medium to obtain the gray intensity, target shape width and width non-uniformity coefficient of the optical image to analyze the water content in the oil. Although the existing monitoring technology can provide information on the state of the lubricating oil to some extent, they often have some limitations, such as low monitoring accuracy, inability to achieve continuous real-time monitoring, lack of self-repair mechanism for the sensor after long-term use, and insufficient intelligence level. These limiting factors greatly reduce the effectiveness and reliability of the monitoring system.

[0004] With the continuous progress of wireless communication technology, the lubricating oil monitoring technology has ushered in new development opportunities. The application of wireless communication technology makes real-time data transmission possible, greatly improving the accuracy and efficiency of monitoring. Through real-time monitoring and early warning systems, potential equipment problems can be discovered and handled in a timely manner, thereby improving the maintenance efficiency of the equipment and reducing the risk of downtime. At the same time, the monitoring system integrated with remote monitoring and maintenance functions provides users with more flexible and convenient monitoring means, making equipment management more efficient and intelligent. SUMMARY

[0005] In view of the above technical problems, the present application provides a preparation method of a micro-water content monitoring sensor, a system thereof and a use method. The sensor can operate stably for a long time, can realize real-time monitoring of the state of the lubricating oil, and has an intelligent early warning function.

[0006] To achieve the above purpose, the present application provides the following technical solutions:

[0007] One of the purposes of the present application is to provide a preparation method of a micro-water content monitoring sensor, comprising the following steps:

[0008] mixing the compound containing a disulfide bond, the nanoparticles and deionized water to obtain a nanoparticle solution;

[0009] adding an anionic fluorocarbon surfactant to the nanoparticle solution to form an aqueous solution by stirring;

[0010] spraying the aqueous solution on the surface of the friction material, drying, and then modifying the dried coating layer with a fluorine-containing silane to obtain a micro-water content monitoring sensor containing a coating layer.

[0011] Further, the compound containing a disulfide bond is selected from one or more of 4'4-diaminodiphenyl disulfide, 2,2'-diaminodiphenyl disulfide, 5,5'-dithiobis(2-nitrobenzoic acid), diallyl trisulfide, dimethyl disulfide, dithiothiophene, lipoic acid and amino acid; and / or

[0012] The nanoparticles are selected from one or more of silica nanoparticles, titanium dioxide nanoparticles, polystyrene nanoparticles and carbon nanotubes; and / or

[0013] The particle size of the nanoparticles is 20-100 nm; and / or

[0014] Further, the compound containing a disulfide bond is selected from one or more of 4'4-diaminodiphenyl disulfide, 2,2'-diaminodiphenyl disulfide, 5,5'-dithiobis(2-nitrobenzoic acid), diallyl trisulfide, dimethyl disulfide, dithiothiophene, lipoic acid and amino acid; and / or

[0015] The fluorine-containing silane is selected from one or more of (3,3,3-trifluoropropyl)methyl dichlorosilane, (3,3,3-trifluoropropyl)methyl dimethoxysilane, (3,3,3-trifluoropropyl)methyl diethoxysilane, 1,3,5-trimethyl-1,3,5-tris(3,3,3-trifluoropropyl)-cyclotrisiloxane, (3,3,3-trifluoropropyl)trichlorosilane, (3,3,3-trifluoropropyl)trimethoxysilane, perfluoroheptyltrimethoxysilane, heptadecafluoroheptyltriethoxysilane, heptadecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, trifluoromethyltrimethylsilane and 1H,1H,2H,2H-perfluorooctyltriethoxysilane.

[0016] Further, the mass ratio of the compound containing a disulfide bond and the nanoparticles is 1:(20-30); and / or

[0017] The mass ratio of the nanoparticles and deionized water is 1:(30-40); and / or

[0018] The mass ratio of the anionic fluorocarbon surfactant to the nanoparticles is (10-20):1; and / or

[0019] The mass ratio of the anionic fluorocarbon surfactant to the fluorosilane is (6-20) g: 20 mg.

[0020] Furthermore, the modification treatment conditions are: deposition at 70-100°C for 30-60 minutes.

[0021] The second objective of this invention is to provide a micro-moisture content monitoring sensor prepared by the above-mentioned preparation method, wherein the coating thickness of the micro-moisture content monitoring sensor is 5-10 μm and the roughness is 3-6 μm.

[0022] A third objective of this invention is to provide a triboelectric sensor, comprising: an electrode material and the aforementioned micro-moisture content monitoring sensor.

[0023] Furthermore, the electrode material is selected from gold, silver, aluminum, copper, titanium, chromium, selenium, iron, manganese, platinum, nickel, palladium, copper alloys, or aluminum alloys; and / or

[0024] The friction material is selected from polydimethylsiloxane, polyethylene, polypropylene, polyvinylidene fluoride, perfluoroethylene propylene, vinylidene chloride acrylonitrile copolymer, polytetrafluoroethylene, polyvinyl chloride, polychlorotrifluoroethylene, polychloroprene, polyisobutylene, polyoxymethylene, polyamide, or polyimide.

[0025] The fourth objective of this invention is to provide a water content monitoring system, comprising:

[0026] A triboelectric sensor array is integrated from multiple sets of triboelectric sensors, with each set containing more than three sets of triboelectric sensors; wherein, the triboelectric sensors are composed of the triboelectric sensors themselves.

[0027] The microprogram control unit is used to receive and process voltage signals generated by the sensor and control the signal transmission and reception of the sensing system.

[0028] The transmission and receiving unit is used to wirelessly transmit voltage signals to the remote monitoring platform and receive command signals from the remote monitoring platform.

[0029] An energy harvesting unit is used to store electrical energy generated by the triboelectric sensor array and to manage the collection and distribution of electrical energy.

[0030] The user control analysis unit is used for information display, control system and signal analysis.

[0031] The sensor prepared by this invention has self-healing and self-repairing properties, and intelligent monitoring is achieved by integrating the sensor and various modules to form a monitoring and control system.

[0032] The fifth object of the present application is to provide an application of the water content monitoring system in detecting the water content of lubricating oil.

[0033] The sixth object of the present application is to provide a method for using the water content monitoring system, comprising the following steps:

[0034] The water content monitoring system is immersed in the lubricating oil, so that the triboelectric sensor array is in full contact with the lubricating oil;

[0035] The triboelectric sensor array generates an electrical signal after contacting water;

[0036] The signal processing module converts the electrical signal into a micro-water content electrical signal after receiving the electrical signal;

[0037] The micro-water content electrical signal is transmitted wirelessly to the user end for display, control and analysis, and the micro-water content in the oil is detected.

[0038] Compared with the prior art, the present application has the following advantages and technical effects:

[0039] The present application uses a high-molecular polymer containing a disulfide bond to modify nanoparticles to form a nanosensing coating, which has the ability to operate stably for a long time. Different characteristic coatings are prepared through modification treatment, and the signal response to water content is realized, achieving high selectivity monitoring. Through the triboelectric sensor array and the signal processing module, the system can monitor the micro-water content in the lubricating oil in real time, and transmit data to remote monitoring equipment through the wireless communication module. In addition, the system also integrates an energy harvesting circuit and a user control unit, realizing an intelligent early warning function, improving the maintenance efficiency of the equipment and reducing the risk of downtime. The system prolongs the service life of the sensor and reduces the maintenance cost.

[0040] The contact surface of the triboelectric nanogenerator sensor based on the present application has oleophobic properties, prolonging the service life of the sensor for detecting in the lubricating oil and reducing the maintenance cost.

[0041] The triboelectric nanogenerator sensor can achieve high selectivity monitoring of the water content in the lubricating oil through different responses of different characteristic coatings to water content.

[0042] The construction of the integrated system realizes real-time monitoring and intelligent early warning of the lubricating oil state, and the design of the energy harvesting and management system enables the sensor system to be self-powered, reducing the dependence on external power supply and improving the stability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0043] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments of the present application illustrated in the drawings and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0044] Figure 1 Schematic of the modified hydrophobic surface spray for Example 1 of the present application;

[0045] Figure 2 Schematic of the water-responsive triboelectric sensor surface for Example 1 of the present application;

[0046] Figure 3 Schematic of the triboelectric sensor array for Example 1 of the present application;

[0047] Figure 4 Schematic of the sensor detection system architecture for Example 1 of the present application;

[0048] Figure 5 Workflow diagram of the lubricant water content detection sensor system for Example 1 of the present application;

[0049] Figure 6 Sensor result plot for Example 1 of the present application (lubricant oil with no water and lubricant oil with water);

[0050] Figure 7 Sensor durability result plot for Example 1 of the present application;

[0051] Figure 8 Schematic of the triboelectric sensor array for Example 2 of the present application. DETAILED DESCRIPTION

[0052] The detailed description set forth below describes various illustrative embodiments of the application. The detailed description is not intended, nor is it to be construed, as being a limit to the application. Rather, the detailed description is intended to provide a description of certain aspects, features, and embodiments of the application.

[0053] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. In addition, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict, the present specification will control.

[0054] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict, the present specification will control.

[0055] Many modifications and variations of the specific embodiments of the application can be made without departing from the scope or spirit of the application, which will be apparent to those skilled in the art. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application. The specification and examples are illustrative only.

[0056] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean inclusion, but not limited to, the listed material or step.

[0057] The embodiment of the application provides a water content monitoring system, which mainly comprises the following steps: step 1, constructing a self-healing and self-repairing nano-sensing coating and performing modification treatment; step 2, designing a triboelectric sensor array to monitor the water content in lubricating oil; and step 3, building an integrated detection sensor system to realize data transmission analysis and system control. The specific steps comprise the following.

[0058] (I) Preparation of a triboelectric sensor

[0059] (1) Preparation of a micro-water content monitoring sensor: mixing a compound containing a disulfide bond, nanoparticles and deionized water to obtain a nanoparticle solution;

[0060] Adding an anionic fluorocarbon surfactant to the nanoparticle solution to form an aqueous solution by stirring;

[0061] Spraying the aqueous solution on the surface of a friction material, drying, and then modifying the dried coating with a fluorine-containing silane to obtain a friction material containing a coating, i.e. a micro-water content monitoring sensor;

[0062] (2) Assembly: assembling the electrode and the micro-water content monitoring sensor into a triboelectric sensor according to a conventional method;

[0063] (II) Construction of a triboelectric sensor array: using micro-water content monitoring sensors with different friction surface coatings to build a triboelectric sensor array to enhance the triboelectric performance of the array and thus realize different response characteristics for different water contents; multiple triboelectric sensors are integrated according to the actual installation environment.

[0064] (III) Construction of an integrated monitoring and control system for real-time monitoring of the micro-water content in lubricating oil

[0065] S1, a triboelectric sensor array, integrated by multiple triboelectric sensors, has different response characteristics for different water contents, and the number of triboelectric sensors is greater than 3 groups; the array is composed of multiple triboelectric sensors to enhance the triboelectric performance of the array;

[0066] S2, a microprogram control unit, configured to receive and process the voltage signal generated by the sensor, control the signal transmission and reception of the sensor system;

[0067] S3, a transmission and reception unit, configured to wirelessly transmit the voltage signal to a remote monitoring platform and receive the command signal from the remote monitoring platform;

[0068] S4, an energy collection unit, configured to store the electrical energy generated by the triboelectric sensor array, manage the collection and distribution of the electrical energy;

[0069] S5, a user control and analysis unit, configured to display information, control the system and analyze the signal.

[0070] In some embodiments, in step (I), the compound containing a disulfide bond is selected from one or more of 4'4-diaminodiphenyl disulfide, 2,2'-diaminodiphenyl disulfide, 5,5'-dithiobis(2-nitrobenzoic acid), a diallyl trisulfide compound, dimethyl disulfide, a dithiothiophene, lipoic acid, and an amino acid. Exemplarily, in the following embodiments of the present application, the compound containing a disulfide bond can be selected as 4'4-diaminodiphenyl disulfide or 2,2'-diaminodiphenyl disulfide for effect verification.

[0071] In some embodiments, in step (I), the nanoparticles are selected from one or more of silica nanoparticles, titanium dioxide nanoparticles, polystyrene nanoparticles, and carbon nanotubes. Exemplarily, in the following embodiments of the present application, the nanoparticles can be selected as silica nanoparticles or titanium dioxide nanoparticles for effect verification. The particle size of the nanoparticles is 20-100 nm.

[0072] In some embodiments, in step (I), the mass ratio of the compound containing a disulfide bond to the nanoparticles is 1:(20-30). Exemplarily, in the following preferred embodiments of the present application, the mass ratio of the compound containing a disulfide bond to the nanoparticles can be selected as 1:20.

[0073] In some embodiments, in step (I), the mass ratio of the nanoparticles to deionized water is 1:(30-40). Exemplarily, in the following preferred embodiments of the present application, the mass ratio of the nanoparticles to deionized water can be selected as 1:30.

[0074] In some embodiments, in step (I), the mass ratio of the anionic fluorocarbon surfactant to the nanoparticles is (10-20):1. Exemplarily, in the following preferred embodiments of the present application, the mass ratio of the anionic fluorocarbon surfactant to the nanoparticles can be selected as 15:1.

[0075] In some embodiments, in step (I), the amount of anionic fluorocarbon surfactant and fluorine-containing silane is adjusted according to the hydrophobic or oleophobic properties of the desired coating to obtain a coating with a specific surface wettability, and thus the present application limits the mass ratio of the anionic fluorocarbon surfactant and fluorine-containing silane to (6-20) g:20 mg. Exemplarily, in the following preferred embodiments of the present application, the mass ratio of the anionic fluorocarbon surfactant and fluorine-containing silane can be selected as 6 g:20 mg, 18 g:20 mg, 20 g:20 mg, or any range between the aforementioned ratios. For example, by adjusting the amount ratio of anionic fluorocarbon surfactant and fluorine-containing silane, two different friction surface coatings of a frictional electric sensor are obtained, and by combining these two together as a unit, more sensor arrays can be obtained by splicing between multiple units. Each unit is the same, but can be combined into different shaped arrays according to actual conditions.

[0076] In some embodiments, in step (I), the modification treatment is performed at a temperature of 70-100°C for 30-60 minutes. Exemplarily, in the following preferred embodiments of the present application, the temperature of the modification treatment can be selected as 80°C or 100°C, and the deposition time can be selected as 30 min or 40 min.

[0077] In some embodiments, in step (I), the coating in the friction material containing the coating has a thickness of 5-10 μm and a roughness of 3-6 μm.

[0078] In some embodiments, in step (I), the fluorine-containing silane is selected from one or more of (3,3,3-trifluoropropyl)methyldichlorosilane, (3,3,3-trifluoropropyl)methyldimethoxysilane, (3,3,3-trifluoropropyl)methyldiethoxysilane, 1,3,5-trimethyl-1,3,5-tris(3,3,3-trifluoropropyl)-cyclotrisiloxane, (3,3,3-trifluoropropyl)trichlorosilane, (3,3,3-trifluoropropyl)trimethoxysilane, perfluoroalkyltrimethoxysilane, heptadecafluoroalkyltriethoxysilane, heptadecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, trifluoromethyltrimethylsilane, and 1H,1H,2H,2H-perfluorooctyltriethoxysilane. Exemplarily, in the following preferred embodiments of the present application, the fluorine-containing silane can be selected from 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0079] In some embodiments, in step (I), the electrode material includes, but is not limited to, gold, silver, aluminum, copper, titanium, chromium, selenium, iron, manganese, platinum, nickel, palladium, copper alloy, aluminum alloy, etc. Exemplarily, in the following preferred embodiments of the present application, the electrode material can be selected as copper or aluminum.

[0080] The electrode material is partially submerged when the oil rises. According to the electron transfer theory, the surface of the friction layer and the oil form bound charges due to the triboelectric effect. Due to the asymmetric distribution of charges, the free electrons of the electrode and the ground transfer from the ground to the electrode until the surface is completely submerged by the oil. Conversely, when the oil falls, the potential distribution changes, and the electrons flow from the electrode to the ground.

[0081] The friction layer material includes, but is not limited to, polydimethylsiloxane, polyethylene, polypropylene, polyvinylidene fluoride, perfluoroethylene propylene, vinylidene fluoride-acrylonitrile copolymer, polytetrafluoroethylene, polyvinyl chloride, polytrifluorochloroethylene, polychlorobutadiene, polyisobutylene, polyformaldehyde, polyamide, polyimide, etc. In the following preferred embodiments of the present application, the friction layer material can be selected from polytetrafluoroethylene or polyimide.

[0082] The shape of the friction layer and the electrode material includes, but is not limited to, sheet, tube or ring;

[0083] The triboelectric sensor is composed of an electrode material and a friction material containing a coating. One end of the electrode is grounded to form a single-electrode triboelectric sensor, which generates a voltage signal based on the principles of triboelectricity and electrostatic induction.

[0084] The triboelectric sensor type includes, but is not limited to, single-electrode or double-electrode form;

[0085] The triboelectric sensor array is composed of multiple groups of single triboelectric sensors, which transmit multiple signals for monitoring the water content in lubricating oil.

[0086] To detect water content, the open-circuit voltage of the triboelectric sensor array under different water content is measured.

[0087] As the water content increases, the voltage output signal of the hydrophobic-coated triboelectric sensor increases, and the voltage output signal of the hydrophilic-coated triboelectric sensor decreases. When water appears in the oil, the triboelectric sensor can monitor the water content.

[0088] In some embodiments, in step (three) S2, the microprogram control unit includes:

[0089] The microprogram control unit uses an embedded processor to execute algorithm processing, analyze digital signals, and transmit signal data of micro water content, including but not limited to STM32, MSP430, Nvidia Jetson Xavier, Jetson Nano, etc.

[0090] An analog-to-digital converter is used to convert the analog signal generated by the sensor into a digital signal.

[0091] A microcontroller is used to execute algorithm processing, analyze digital signals, and transmit signal data of the micro-water content.

[0092] In some embodiments, in S3 of step (three), the transmission receiving unit comprises:

[0093] A sending module is configured to send sensor signals to a remote user terminal.

[0094] A receiving module is configured to receive command signals from the user terminal.

[0095] Wireless transmission includes but is not limited to Bluetooth transmission, Wi-Fi network connection transmission, 4G / 5G transmission, etc.

[0096] In some embodiments, in S4 of step (three), the energy collection circuit comprises:

[0097] The energy collection unit is used to store the electrical energy generated by the triboelectric sensor array.

[0098] An embedded processor is used to manage the collection and distribution of electrical energy, ensuring stable operation of the system.

[0099] In some embodiments, in S5 of step (three), the user control analysis unit comprises:

[0100] A display unit is used to display the monitoring data of the micro-water content in the lubricating oil in real time.

[0101] A control unit is used to receive user operation instructions and adjust the operating state of the monitoring system according to the instructions.

[0102] An analysis unit is used to analyze and process signals to detect the micro-water content in the lubricating oil.

[0103] The embodiment of the present application provides a use method of the water content monitoring system, which comprises the following steps:

[0104] The water content monitoring system is immersed in the lubricating oil, so that the triboelectric sensor array is in full contact with the lubricating oil.

[0105] The triboelectric sensor array generates an electrical signal after contacting water.

[0106] The signal processing module converts the electrical signal into an electrical signal of the micro-water content after receiving the electrical signal.

[0107] The electrical signal of the micro-water content is transmitted to the user terminal for display, control and analysis, and the micro-water content in the oil is detected.

[0108] When the water content exceeds the preset threshold, a warning signal is sent through the alarm system.

[0109] The water content monitoring system is immersed in lubricating oil, so that the sensor array is in full contact with the lubricating oil, the presence of water molecules in the lubricating oil is detected through the sensor array in the monitoring system, and a corresponding electric signal is generated, the electric signal is collected by using a signal processing unit and is converted into an electric signal of the micro water content, data is transmitted to a remote monitoring device through a transmission and receiving unit, and real-time monitoring and analysis are performed; the micro water content in the oil is monitored and analyzed through a user analysis unit.

[0110] The micro water content monitoring sensor prepared by the preparation method of the micro water content monitoring sensor is also provided in the embodiment of the application, and the coating in the micro water content monitoring sensor has a hierarchical cell-like structure with a thickness of 5-10 μm and a roughness of 3-6 μm. The wetting properties of the coating include but are not limited to oil-repellent superhydrophobicity, oil-repellent hydrophobicity, oil-repellent hydrophilicity and the like.

[0111] The micro water content monitoring sensor array is also provided in the embodiment of the application.

[0112] Unless otherwise specified, the "room temperature" in the application refers to 20-30 ℃.

[0113] The raw materials used in the application are all commercially available.

[0114] The technical solutions of the application are further described below through examples.

[0115] Example 1

[0116] A water content monitoring system:

[0117] (I) Preparation of the micro water content monitoring sensor:

[0118] 4'4-diaminodiphenyl disulfide, silica nanoparticles (with a particle size of 20-100 nm) and deionized water are mixed (the mass ratio of 4'4-diaminodiphenyl disulfide to silica nanoparticles is 1:20, and the mass ratio of silica nanoparticles to deionized water is 1:30, to obtain a silica nanoparticle solution;

[0119] An anionic fluorocarbon surfactant is added to the silica nanoparticle solution, and stirring is continued to form an aqueous solution; the mass ratio of the anionic fluorocarbon surfactant to the silica nanoparticles is 15:1;

[0120] The aqueous solution is sprayed on the surface of a polytetrafluoroethylene material (see Figure 1 ), dried in air, and repeatedly sprayed until a coating layer is formed on the surface of the polytetrafluoroethylene material;

[0121] The coating is placed in a condition of 80℃, and the coating is modified by using 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane by deposition method for 30min to obtain a polytetrafluoroethylene friction material containing a coating, i.e., a micro-water content monitoring sensor;

[0122] In the same way, by changing the mass ratio of anionic fluorocarbon surfactant and fluorine-containing silane, the following friction surface coating friction electricity sensors with different friction surfaces are obtained, respectively:

[0123] Group a: when the mass ratio of anionic fluorocarbon surfactant and fluorine-containing silane is 18g:20mg, a coating with a thickness of 10μm, a roughness of 5μm, and oleophobicity and hydrophilicity is obtained;

[0124] Group b: when the mass ratio of anionic fluorocarbon surfactant and fluorine-containing silane is 6g:20mg, a coating with a thickness of 10μm, a roughness of 5μm, and oleophobicity and hydrophobicity is obtained;

[0125] (ii) Construction of a friction electricity sensor array:

[0126] The friction electricity sensor is composed of an electrode material and the micro-water content monitoring sensor prepared above;

[0127] Each group of the sheet-shaped polytetrafluoroethylene friction material containing a coating prepared above is assembled with a sheet-shaped copper electrode to form a friction electricity sensor array; one end of the electrode is grounded to form a single-electrode friction electricity sensor, which generates a voltage signal based on the principle of triboelectricity and electrostatic induction;

[0128] The copper electrode is partially submerged when the oil rises, and according to the electron transfer theory, the polytetrafluoroethylene surface and the oil form bound charges due to the triboelectric effect; due to the asymmetric distribution of charges, electron transfer occurs from the ground end to the electrode, and then from the electrode end to the ground end when the oil falls;

[0129] The friction electricity sensor array is composed of friction electricity sensors with different friction surface coatings, so it has different response characteristics for water content (see Figure 2 );

[0130] The array is composed of two groups of friction electricity sensors to enhance the triboelectric performance of the array;

[0131] The two groups of friction electricity sensors are integrated according to the actual installation environment, as shown in Figure 3 ;

[0132] (iii) Construction of an integrated monitoring and control system (as shown in Figure 4 ), for real-time monitoring of the micro-water content in lubricating oil:

[0133] S1, the triboelectric sensor array prepared in step (ii);

[0134] S2, a microprogram control unit, comprising:

[0135] An embedded processor STM32 series is used to execute algorithm processing, analyze digital signals, and transmit signal data of the micro water content;

[0136] An analog-to-digital converter is used to convert analog signals generated by the sensor into digital signals;

[0137] A microcontroller is used to execute algorithm processing, analyze digital signals, and transmit signal data of the micro water content;

[0138] S3, a transmission receiving unit, comprising:

[0139] A sending module is used to send sensor signals to a remote user end;

[0140] A receiving module is used to receive command signals from the user end;

[0141] Wireless transmission uses Wi-Fi network connection transmission;

[0142] S4, an energy collection unit, comprising:

[0143] An energy collection module is used to store electrical energy generated by the triboelectric sensor array;

[0144] An embedded processor is used to manage the collection and distribution of electrical energy and ensure stable operation of the system;

[0145] S5, a user control analysis unit, comprising:

[0146] A display module is used to display monitoring data of the micro water content in the lubricating oil in real time;

[0147] A control module is used to receive operation instructions from the user and adjust the operating state of the monitoring system according to the instructions.

[0148] An analysis module is used to analyze and process signals and detect the micro water content in the lubricating oil.

[0149] When the computer terminal is used, the method for analyzing and processing signals comprises:

[0150] When the water content exceeds the preset threshold value, a warning signal is sent through the alarm system. According to the current voltage or component change trend, the water content state in the lubricating oil is warned, and when the voltage is greater than the preset threshold value, the alarm system is automatically started, the staff maintains the machine and replaces the new lubricating oil. The overall working process is as shown in Figure 5 .

[0151] To realize the detection of water content, the open circuit voltage of the triboelectric sensor array under different water contents is measured. The test method is as follows: by adding water in oil, the voltage signal change is detected by an electrometer, and the signal change is collected by a signal collection module through a computer. The results are shown in FIGS. 8 and 9, wherein the left graph is the result without water, and the right graph is the result after adding water. It is found that with the increase of water content, the voltage output signal of the triboelectric sensor with hydrophobic coating increases, and the voltage output signal of the triboelectric sensor with hydrophilic coating decreases. When water appears in the oil, the triboelectric sensor can realize the monitoring of the contaminant being water. Figure 6

[0152] In the triboelectric sensor test, a linear motor is used to make the cuboid oil tank circulate, so that the sensor surface is in circulation contact with the oil. The voltage signal after different circulation times is measured by an electrometer (Keithley 6514).

[0153] Figure 7 For the durability of the triboelectric sensor, it can be seen from FIG. 10 that after multiple cycles, a relatively high voltage output can still be ensured, which indicates good durability. Figure 7

[0154] Example 2

[0155] A water content monitoring system:

[0156] (I) Preparation of a micro-water content monitoring sensor:

[0157] 2,2'-diaminodiphenyl disulfide, titanium dioxide nanoparticles (particle size between 20-100 nm) and deionized water are mixed (the mass ratio of 2,2'-diaminodiphenyl disulfide and nanoparticles is 1:30, and the mass ratio of titanium dioxide nanoparticles and deionized water is 1:30) to obtain a nanoparticle solution;

[0158] An anionic fluorocarbon surfactant is added to the titanium dioxide nanoparticle solution, and stirring is continued to form an aqueous solution; the mass ratio of the anionic fluorocarbon surfactant to the titanium dioxide nanoparticles is 15:1;

[0159] The aqueous solution is sprayed on the surface of the polyimide material, dried in air, and repeated until a coating layer is formed on the surface of the polytetrafluoroethylene material;

[0160] The coating layer is placed at a temperature of 100°C, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane is used for modification treatment of the coating layer by deposition for 40 min to obtain a polyimide friction material containing a coating layer, i.e., a micro-water content monitoring sensor.

[0161] In the same way, by changing the mass ratio of the anionic fluorocarbon surfactant and the fluorine-containing silane, the following triboelectric sensors with different friction surface coatings are obtained, respectively:​​

[0162] Group a: when the mass ratio of anionic fluorocarbon surfactant and fluorine-containing silane is 20g:20mg, an oil-repellent and water-repellent coating with a thickness of 10μm and a roughness of 5μm is obtained;

[0163] Group b: when the mass ratio of anionic fluorocarbon surfactant and fluorine-containing silane is 6g:20mg, an oil-repellent and water-repellent coating with a thickness of 10μm and a roughness of 5μm is obtained;

[0164] (ii) Constructing a triboelectric sensor array:

[0165] The triboelectric sensor is composed of an electrode material and the micro-water content monitoring sensor prepared above;

[0166] Each group of the above-prepared polyimide friction material with a coating is assembled with a sheet-shaped aluminum electrode to form a triboelectric sensor array; one end of the electrode is grounded to form a single-electrode triboelectric sensor, which generates a voltage signal based on the principle of triboelectricity and electrostatic induction;

[0167] The aluminum electrode is partially submerged when the oil rises, and according to the electron transfer theory, the polyimide surface and the oil form bound charges due to the triboelectric effect; due to the asymmetric distribution of charges, electron transfer occurs from the ground end to the electrode, and from the electrode end to the ground end when the oil falls;

[0168] The triboelectric sensor array is composed of triboelectric sensors with different friction surface coatings, so it can have different response characteristics for water content;

[0169] The array is composed of two groups of triboelectric sensors to enhance the triboelectric performance of the array;

[0170] The two groups of triboelectric sensors are integrated according to the actual installation environment, and two groups form a unit, and two units form an array, as shown in Figure 8 ;

[0171] (iii) Constructing an integrated monitoring and control system for real-time monitoring of micro-water content in lubricating oil:

[0172] S1, using the triboelectric sensor array prepared in step (ii);

[0173] S2, a microprogram control unit, including:

[0174] An embedded processor MSP430 series is used to execute algorithm processing, analyze digital signals, and transmit micro-water content signal data;

[0175] An analog-to-digital converter is used to convert the analog signal generated by the sensor into a digital signal;

[0176] A microcontroller is used to perform algorithm processing, analyze the digital signal, and transmit signal data of the micro-water content;

[0177] S3, a transmission receiving unit, comprising:

[0178] A sending module is used to send sensor signals to a remote user terminal;

[0179] A receiving module is used to receive command signals from the user terminal;

[0180] Wireless transmission uses Wi-Fi network connection transmission;

[0181] S4, an energy collection unit, comprising:

[0182] The energy collection unit is used to store the electrical energy generated by the triboelectric sensor array;

[0183] An embedded processor is used to manage the collection and distribution of electrical energy, ensuring stable operation of the system;

[0184] S5, a user control analysis unit, comprising:

[0185] A display unit is used to display the monitoring data of the micro-water content in the lubricating oil in real time;

[0186] A control unit is used to receive the operation instructions of the user and adjust the operating state of the monitoring system according to the instructions.

[0187] An analysis unit is used to analyze and process signals and detect the micro-water content in the lubricating oil.

[0188] When the computer terminal is used, the method for analyzing and processing signals comprises:

[0189] When the water content exceeds the preset threshold value, a warning signal is sent through the alarm system. According to the current voltage or component change trend, the water content state in the lubricating oil is warned, and when the voltage is greater than the preset threshold value, the alarm system is automatically started, the staff maintains the machine and replaces the new lubricating oil.

[0190] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of making a micro-water content monitoring sensor, characterized by, The method comprises the following steps: mixing a compound containing a disulfide bond, nanoparticles and deionized water to obtain a nanoparticle solution; adding an anionic fluorocarbon surfactant to the nanoparticle solution and stirring to form an aqueous solution; spraying the aqueous solution onto the surface of a friction material, drying, and then modifying the dried coating layer with a fluorine-containing silane to obtain a micro-water content monitoring sensor.

2. The method for preparing a micro-water content monitoring sensor according to claim 1, wherein: the compound containing a disulfide bond is selected from one or more of 4'4-diaminodiphenyl disulfide, 2,2'-diaminodiphenyl disulfide, 5,5'-dithiobis(2-nitrobenzoic acid), diallyl trisulfide, dimethyl disulfide, dithiothiophene, thioctic acid and amino acid; and / or the nanoparticles are selected from one or more of silica nanoparticles, titanium dioxide nanoparticles, polystyrene nanoparticles and carbon nanotubes; and / or the particle size of the nanoparticles is 20-100 nm; and / or the fluorine-containing silane is selected from one or more of (3,3,3-trifluoropropyl)methyl dichlorosilane, (3,3,3-trifluoropropyl)methyl dimethoxysilane, (3,3,3-trifluoropropyl)methyl diethoxysilane, 1,3,5-trimethyl-1,3,5-tris(3,3,3-trifluoropropyl)-cyclotrisiloxane, (3,3,3-trifluoropropyl)trichlorosilane, (3,3,3-trifluoropropyl)trimethoxysilane, perfluorophenyltrimethoxysilane, heptadecafluorophenyltriethoxysilane, heptadecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, trifluoromethyltrimethylsilane and 1H,1H,2H,2H-perfluorooctyltriethoxysilane; and / or the friction material is selected from polydimethylsiloxane, polyethylene, polypropylene, polyvinylidene fluoride, perfluoroethylene propylene, vinylidene chloride acrylonitrile copolymer, polytetrafluoroethylene, polyvinyl chloride, polytrifluorochloroethylene, polychlorobutadiene, polyisobutylene, polyformaldehyde, polyamide or polyimide.

3. The method for preparing a micro-water content monitoring sensor according to claim 1, wherein: the mass ratio of the compound containing a disulfide bond to the nanoparticles is 1:(20-30); and / or the mass ratio of the nanoparticles to deionized water is 1:(30-40); and / or the mass ratio of the anionic fluorocarbon surfactant to the nanoparticles is (10-20):1; and / or the mass ratio of the anionic fluorocarbon surfactant to the fluorine-containing silane is (6-20)g:20mg.

4. The method of claim 1, wherein the micro-water content monitoring sensor is prepared by the steps of: the modification treatment is performed at 70-100°C for 30-60 minutes.

5. A micro-water content monitoring sensor prepared by the method of any one of claims 1 to 4, characterized in that, the thickness of the coating layer in the micro-water content monitoring sensor is 5-10μm and the roughness is 3-6μm.

6. A triboelectric sensor, comprising: comprising: an electrode material and the micro-water content monitoring sensor according to claim 5.

7. The triboelectric sensor of claim 6, wherein, the electrode material is selected from gold, silver, aluminum, copper, titanium, chromium, selenium, iron, manganese, platinum, nickel, palladium, copper alloy or aluminum alloy.

8. A water content monitoring system characterized by, comprising: a triboelectric sensor array integrated by 3 or more groups of the triboelectric sensor according to claim 6 or 7. Microprogram control unit, for receiving and processing voltage signals generated by the sensor, controlling signal transmission and reception of the sensing system; Transmission and reception unit, for wirelessly transmitting voltage signals to the remote monitoring platform and receiving command signals from the remote monitoring platform; Energy collection unit, for storing the electrical energy generated by the triboelectric sensor array, managing the collection and distribution of electrical energy; User control analysis unit, for information display, control system and signal analysis.

9. The use of the water content monitoring system according to claim 8 in detecting the water content of lubricating oil.

10. A method of using a water content monitoring system as claimed in claim 8, characterized in that, The steps include: Immerse the water content monitoring system in the lubricating oil, so that the triboelectric sensor array is in full contact with the lubricating oil; The triboelectric sensor array generates an electrical signal after contacting water; The signal processing module converts the electrical signal into a micro water content electrical signal after receiving the electrical signal; The micro water content electrical signal is wirelessly transmitted to the user end for display, control and analysis, and the micro water content in the oil is detected.

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