Preparation method of fe3o4-pdms photothermal response micro-column surface with lubricating oil directional transportation

Abstract

The application discloses a Fe3O4-PDMS photothermal response micro-column surface preparation method with lubricating oil directional transportation, first designs a biomimetic pitcher-rice leaf composite structure; then carries out laser processing on the biomimetic pitcher-rice leaf composite structure on a metal surface; configures and coats a Fe3O4-PDMS mixture; prepares a micro-column structure; carries out silane coupling agent treatment; finally, carries out nanoparticle modification to obtain the Fe3O4-PDMS photothermal response micro-column surface. The application can realize remote, efficient and controllable transportation of lubricating oil, supplement lubricating medium for an oil-starved area in time, improve the lubrication state of a friction pair, avoid mechanical wear caused by oil starvation, and improve the service life and service reliability of a space vehicle.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photo-thermal response surface design and preparation, and particularly relates to a Fe3O4-PDMS photo-thermal response micro-column surface preparation method with lubricating oil directional transportation. BACKGROUND

[0002] The moving parts of a spacecraft generate a large amount of heat in the friction pair area during movement, but the space environment makes it difficult for the heat to dissipate, forming a sharp temperature gradient at the friction surface. The lubricating liquid is affected by the temperature gradient and "creeps" from the high-temperature to the low-temperature area, making the friction interface in a starved oil lubrication state, which leads to severe wear of the moving parts, reduces the working life of the mechanical parts, and even causes the spacecraft to fail prematurely. To solve the problem of starved oil lubrication caused by lubricating oil "creep", achieve controllability of lubricating liquid supply, and enhance the long-distance control performance of the lubricating liquid migration process to improve the lubricating performance of the moving parts and reduce single-point failures, it is of great significance for long-life spacecraft.

[0003] Responsive functional surfaces refer to surfaces whose physical / chemical properties change under the action of an external field, changing the surface wettability and achieving the effect of driving liquid droplets. Common responsive functional surfaces include electrically responsive functional surfaces, magnetically responsive functional surfaces, light-responsive functional surfaces, thermally responsive functional surfaces, acoustically responsive functional surfaces, and mechanically stress-responsive functional surfaces. Light-responsive functional surfaces have the advantages of remote operation and flexible operation, and their response speed and stability are relatively good. Light is a flexible external field, and its size, shape, irradiation time, intensity, and process adjustability make it have advantages in liquid droplet operation. Light-driven liquid droplet operation is suitable for remote operation, and the formation of a non-uniform temperature field by light can drive liquid droplets to run in real time. Light-responsive materials are divided into three categories: organic responsive materials, inorganic responsive materials, and other responsive materials. Inorganic light-responsive materials mainly include various photosensitive inorganic oxides such as TiO2, V2O5, WO3, ZnO, Ga2O3, and SnO2. These materials can produce surface lattice defects under light irradiation, and water molecules can invade the damaged lattice, causing the wettability of the material to change. Inorganic light-responsive materials have the advantages of low toxicity and good chemical / thermal stability. Organic light-responsive materials contain photochromic functional groups such as spiropyrans, diarylethylene, and azobenzene, which have the ability to reversibly change molecular configuration under ultraviolet / visible light, which can cause the surface wettability to change. Light-responsive organic materials have the advantages of chemical modification and reaction diversity. Other light-responsive materials use the surface black color attribute to absorb more light and convert it into a heat field, such as Fe3O4, carbon black, and MoS2. SUMMARY

[0004] The application aims to provide a Fe3O4-PDMS photothermal response micro-column surface preparation method with lubricating oil directional delivery, which can realize remote, efficient and controllable delivery of lubricating oil, supplement lubricating medium for oil-starved areas in time, improve the lubrication state of friction pairs, avoid mechanical wear caused by oil starvation, and improve the service life and reliability of space vehicles.

[0005] The technical scheme adopted by the application is that the Fe3O4-PDMS photothermal response micro-column surface preparation method with lubricating oil directional delivery is implemented according to the following steps.

[0006] Step 1, design a biomimetic pitcher-rice leaf composite structure.

[0007] Step 2, laser process the biomimetic pitcher-rice leaf composite structure on a metal surface.

[0008] Step 3, Fe3O4-PDMS mixture preparation and coating.

[0009] Step 4, micro-column structure preparation.

[0010] Step 5, silane coupling agent treatment.

[0011] Step 6, nanoparticle modification, and obtain the Fe3O4-PDMS photothermal response micro-column surface.

[0012] The application also has the characteristics that,

[0013] Step 1 is implemented according to the following steps.

[0014] Step 1.1, the biomimetic pitcher-rice leaf composite structure is composed of a “human” shape structure of a biomimetic pitcher and a linear structure of a biomimetic rice leaf, and the composite structure is centrally symmetrically arranged, the upper and lower structures are composed of the “human” shape track of the biomimetic pitcher, and the upper part and the lower part are connected through the linear structure of the biomimetic rice leaf to form a composite structure for directional delivery of liquid drops.

[0015] Step 1.2, the linear width Wd of the biomimetic rice leaf connecting structure is 20-80 μm, the linear spacing d is 0.1-0.5 mm, the linear track angle Dα is 0-5°, and the linear track length W1 is 1-3 mm.

[0016] Step 1.3, the biomimetic pitcher track width Wz is 0.5-2 mm, the linear width b1 of a single biomimetic pitcher structure is 100-150 μm, the spacing b2 between the two opposite single biomimetic pitcher structures is 50-200 μm, the inclination angle Zα of the single biomimetic pitcher structure is 30-90°, a plurality of biomimetic pitcher structures are arranged at equal intervals along the length direction, and the arrangement spacing h between adjacent two single biomimetic pitcher structures is 500-700 μm.

[0017] Step 2 is specifically implemented according to the following steps:

[0018] Step 2.1, polishing the metal test piece to remove the surface oxide layer, the metal test piece being any one of titanium alloy, copper, steel, aluminum alloy;

[0019] Step 2.2, the metal test piece obtained in step 2.1 is ultrasonically cleaned with anhydrous ethanol for 5-10 min to remove surface lipids and organic matter, then the metal test piece surface is rinsed with deionized water to remove residual anhydrous ethanol on the surface, and the surface is dried for standby;

[0020] Step 2.3, the metal test piece is placed horizontally, and after marking the laser processing area on the surface of the test piece, the bionic nepenthes-rice leaf composite structure is marked and engraved, and the laser processing process is set as follows: laser power is 20-30 W, laser frequency is 20-50 KHz, pulse width is 100-300 ns, processing speed is 50-100 mm / s, and processing times is 1-3 times;

[0021] Step 2.4, the surface of the metal test piece with the bionic nepenthes-rice leaf composite structure is polished again using 1000-2000# sandpaper to remove burrs generated by laser processing, then surface polishing treatment is performed, the metal test piece surface is rinsed with deionized water, and then ultrasonically cleaned in anhydrous ethanol for 5-10 min to remove residual metal debris and polishing abrasive particles on the test piece surface.

[0022] Step 3 is specifically implemented according to the following steps:

[0023] Step 3.1, mixing polydimethylsiloxane and curing agent in a mass ratio of 5:1-10:1 and stirring uniformly to obtain a PDMS mixture;

[0024] Step 3.2, mixing Fe3O4 particles and the PDMS mixture obtained in step 3.1 in a mass ratio of 0.7:1-1:1, and fully mixing the Fe3O4 particles and the PDMS mixture by stirring to obtain a Fe3O4-PDMS mixture, the particle size of the Fe3O4 particles being one or more of 100 nm-10 μm particle size microparticles;

[0025] Step 3.3, using a four-sided film applicator to uniformly scrape the Fe3O4-PDMS mixture onto the surface of the test piece, so that the bionic nepenthes-rice leaf composite structure is filled with the Fe3O4-PDMS mixture, and the Fe3O4-PDMS mixture in other areas of the surface is cleaned and wiped off, so that only the bionic nepenthes-rice leaf composite structure on the surface is filled.

[0026] Step 4 is specifically implemented according to the following steps:

[0027] Step 4.1, the fluorination liquid is mixed by anhydrous ethanol and fluorosilane, the volume fraction of fluorosilane is 1%-5%, and the fluorosilane is one or more of trichloro-tridecafluoro-n-octylsilane, triethoxy-1H, 1H, 2H, 2H-tridecafluoro-n-octylsilane and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane;

[0028] Step 4.2, the slide is placed in the fluorination liquid of step 4.1, and is soaked for 5-10 min, so as to complete the low surface energy treatment;

[0029] Step 4.3, the slide treated by the low surface energy in step 4.2 is supported on the surface of the test piece obtained in step 3 by using copper foil as a gasket, and the thickness of the copper foil gasket is 100-400 μm;

[0030] Step 4.4, the structure obtained in step 4.3 is horizontally placed on the surface of a magnet, and is statically placed for 1-5 min, so as to obtain a micro column structure under the guidance of a magnetic field, and the magnet is any one of N37, N42 or N52;

[0031] Step 4.5, the micro column structure sample obtained in step 4.4 and the magnet are placed in a blast drying oven for curing treatment, the curing temperature is 70-100 ℃, the curing time is 1-3 h, and the surface of the Fe3O4-PDMS micro column is cured.

[0032] Step 5 is implemented according to the following steps:

[0033] Step 5.1, a KH-550 ethanol solution is prepared by mixing KH-550 silane coupling agent and anhydrous ethanol, and the mass ratio of the KH-550 silane coupling agent is 1%-5%;

[0034] Step 5.2, the surface test piece of the Fe3O4-PDMS micro column obtained in step 4.5 is soaked in the KH-550 ethanol solution obtained in step 5.1, the temperature is 20-25 ℃, and the soaking time is 1-5 min;

[0035] Step 5.3, the surface test piece obtained in step 5.2 is cultured in a temperature environment of 20-25 ℃ for 10-20 h, so as to complete the silane coupling agent treatment.

[0036] Step 6 is implemented according to the following steps:

[0037] Step 6.1, a nanoparticle modification liquid is prepared by mixing SiO2 nanoparticles and anhydrous ethanol, the mass fraction of the SiO2 nanoparticles is 1%-5%, and the particle size of the SiO2 nanoparticles is 10-50 nm; after the SiO2 nanoparticles and the anhydrous ethanol are mixed, the temperature is set to 40-60 ℃, the magnetic stirring is performed at a speed of 200-400 r / min for 5-10 min, and the preparation of the nanoparticle modification liquid is completed;

[0038] Step 6.2, the test piece treated by the silane coupling agent in step 5 is horizontally placed in a nanoparticle modification liquid, soaked for 1-5 min, and left to stand for 10-20 min after being taken out;

[0039] Step 6.3, the test piece in step 6.2 is again horizontally placed in a nanoparticle modification liquid, soaked for 1-5 min, and left to stand for 1-2 h after being taken out, to obtain a Fe3O4-PDMS photothermal response microcolumn surface with directional transport of lubricating oil;

[0040] Step 6.4, the surface of the test piece in step 6.3 is infiltrated with lubricating oil, and the amount of lubricating oil infiltration is 200-400 μL of one or more of PAO2, PAO4, and PFPE lubricating oil, to obtain a Fe3O4-PDMS photothermal response microcolumn surface with directional transport of water-based droplets.

[0041] The beneficial effects of the present application are that the photothermal response lubricating liquid transport is a high-efficiency transport method in droplet remote transport, the present application can obtain good droplet photothermal driving performance and wettability after treatment on various metal surfaces, can effectively alleviate the problem of oil shortage lubrication through lubricating liquid supplement, and can reduce the friction and wear of moving parts by moving the lubricating oil to the friction area through photothermal driving, thereby improving the design life of the workpiece, and has good social and economic value. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a schematic diagram of a bionic pitcher-rice leaf composite structure and various parameters designed by the present application;

[0043] Figure 2 is a SEM image of a local area of the surface of the bionic pitcher-rice leaf composite structure of the present application;

[0044] Figure 3 is a process of directional self-driving of a droplet on the surface of the bionic pitcher-rice leaf composite structure of the present application;

[0045] Figure 4 is a SEM image of the PDMS-Fe3O4 microcolumn structure filled in the bionic pitcher-rice leaf composite structure of the present application. DETAILED DESCRIPTION

[0046] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0047] The present application has a preparation method of a Fe3O4-PDMS photothermal response microcolumn surface with directional transport of lubricating oil, which is specifically implemented according to the following steps:

[0048] Step 1, design a bionic pitcher-rice leaf composite structure;

[0049] Combination Figure 1 , Figure 2 , Figure 3 Step 1 is implemented in the following steps:

[0050] Step 1.1: The biomimetic pitcher plant-rice leaf composite structure consists of two parts: the "human" shaped structure of the biomimetic pitcher plant and the linear structure of the biomimetic rice liquid. The composite structure is centrally symmetrically arranged. The upper and lower structures are formed by the "human" shaped track of the biomimetic pitcher plant. The upper and lower parts are connected by the linear structure of the biomimetic rice leaf to form a composite structure for the directional transport of droplets.

[0051] Step 1.2, Bionic rice leaf connection structure, linear width W of rice leaf d The linear spacing is 20-80μm, the linear pitch d is 0.1-0.5mm, the linear track angle Dα is 0-5°, and the linear track length W1 is 1-3mm.

[0052] Step 1.3: The width Wz of the biomimetic pitcher plant track is 0.5-2mm, the linear width b1 of a single biomimetic pitcher plant structure is 100-150μm, the spacing b2 between two opposite single biomimetic pitcher plant structures is 50-200μm, the tilt angle Zα of a single biomimetic pitcher plant structure is 30-90°, multiple sets of biomimetic pitcher plant structures are arranged at equal intervals along the length direction, and the spacing h between two adjacent single biomimetic pitcher plant structures is 500-700μm.

[0053] Step 2: Laser processing of the metal surface to create a biomimetic pitcher plant-rice leaf composite structure;

[0054] Step 2 is implemented in the following steps:

[0055] Step 2.1: Grind the metal specimen to remove the surface oxide layer. The metal specimen can be any one of titanium alloy, copper, steel, or aluminum alloy.

[0056] Step 2.2: Clean the metal specimen obtained in step 2.1 with anhydrous ethanol using ultrasonic cleaning for 5-10 minutes to remove surface grease and organic matter. Then rinse the surface of the metal specimen with deionized water to remove residual anhydrous ethanol. Dry the surface and set aside for later use.

[0057] Step 2.3: Place the metal specimen horizontally, mark the laser processing area on the specimen surface, and then start marking the biomimetic pitcher plant-rice leaf composite structure. During the laser processing, set the laser power to 20-30W, the laser frequency to 20-50KHz, the pulse width to 100-300ns, the processing speed to 50-100mm / s, and the number of processing times to 1-3.

[0058] Step 2.4, the surface of the metal test piece of the notched biomimetic nepenthes-rice leaf composite structure is polished again using 1000-2000# sandpaper to remove burrs generated by laser processing on the surface, and then surface polishing treatment is performed, the metal test piece surface is washed with deionized water, and then placed in anhydrous ethanol for ultrasonic cleaning for 5-10 min to remove residual metal debris and polishing abrasive particles on the surface of the test piece.

[0059] Step 3, Fe3O4-PDMS mixture preparation and coating;

[0060] Step 3 is implemented according to the following steps:

[0061] Step 3.1, polydimethylsiloxane and curing agent are mixed in a mass ratio of 5:1-10:1 and stirred uniformly to obtain a PDMS mixture;

[0062] Step 3.2, Fe3O4 particles and the PDMS mixture obtained in step 3.1 are mixed in a mass ratio of 0.7:1-1:1, and Fe3O4 particles and the PDMS mixture are fully mixed and uniformly mixed by stirring to obtain a Fe3O4-PDMS mixture, the particle size of the Fe3O4 particles being one or more of 100 nm-10 μm particle size microparticles;

[0063] Step 3.3, the Fe3O4-PDMS mixture is uniformly scraped and coated on the surface of the test piece, so that the Fe3O4-PDMS mixture fills the inside of the biomimetic nepenthes-rice leaf composite structure, and the Fe3O4-PDMS mixture in other areas of the surface is cleaned and wiped off, so that only the biomimetic nepenthes-rice leaf composite structure is filled on the surface.

[0064] In combination Figure 4 Step 4, micro-column structure preparation;

[0065] Step 4 is implemented according to the following steps:

[0066] Step 4.1, the fluorination liquid is mixed from anhydrous ethanol and fluorosilane, the volume fraction of fluorosilane being 1%-5%, and the fluorosilane being one or more of trichloro-tridecafluoro-n-octylsilane, triethoxy-1H, 1H, 2H, 2H-tridecafluoro-n-octylsilane, and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane;

[0067] Step 4.2, the glass slide is placed in the fluorination liquid of step 4.1 and soaked for 5-10 min to complete the low surface energy treatment;

[0068] Step 4.3, copper foil is used as a gasket, and the glass slide subjected to low surface energy treatment in step 4.2 is placed on the surface of the test piece obtained in step 3, and the thickness of the copper foil gasket is 100-400 μm;

[0069] Step 4.4, place the structure obtained in step 4.3 horizontally on the surface of a magnet, and stand for 1-5 min to obtain the micro-column structure under the guidance of the magnetic field; the magnet is any one of N37, N42, or N52;

[0070] Step 4.5, place the micro-column structure sample obtained in step 4.4 and the magnet in a drying oven for curing treatment, the curing temperature is 70-100°C, and the curing time is 1-3 h, to complete the curing of the Fe3O4-PDMS micro-column surface.

[0071] Step 5, silane coupling agent treatment;

[0072] Step 5 is implemented according to the following steps:

[0073] Step 5.1, prepare a KH-550 ethanol solution by mixing KH-550 silane coupling agent and anhydrous ethanol, and the mass ratio of the KH-550 silane coupling agent is 1%-5%;

[0074] Step 5.2, immerse the Fe3O4-PDMS micro-column surface sample obtained in step 4.5 in the KH-550 ethanol solution obtained in step 5.1, the temperature is 20-25°C, and the immersion time is 1-5 min;

[0075] Step 5.3, complete the silane coupling agent treatment by placing the surface sample obtained in step 5.2 in a temperature environment of 20-25°C for 10-20 h.

[0076] Step 6, nanoparticle modification to obtain a Fe3O4-PDMS photothermal response micro-column surface.

[0077] Step 6 is implemented according to the following steps:

[0078] Step 6.1, prepare a nanoparticle modification liquid by mixing SiO2 nanoparticles and anhydrous ethanol, the mass fraction of the SiO2 nanoparticles is 1%-5%, and the particle size of the SiO2 nanoparticles is 10-50 nm; after mixing the SiO2 nanoparticles and the anhydrous ethanol, set the temperature to 40-60°C, and magnetically stir at a speed of 200-400 r / min for 5-10 min to complete the preparation of the nanoparticle modification liquid;

[0079] Step 6.2, place the sample treated with the silane coupling agent in step 5 horizontally in the nanoparticle modification liquid, immerse for 1-5 min, and stand for 10-20 min after taking out;

[0080] Step 6.3, place the sample in step 6.2 again horizontally in the nanoparticle modification liquid, immerse for 1-5 min, and stand for 1-2 h after taking out to obtain a Fe3O4-PDMS photothermal response micro-column surface with directional transportation of lubricating oil;

[0081] Step 6.4, the surface of the test piece after step 6.3 is infiltrated with lubricating oil, the amount of lubricating oil infiltration is 200-400 μL, and the lubricating oil is one or more of PAO2, PAO4, and PFPE lubricating oil, to obtain a Fe3O4-PDMS photothermal response microcolumnar surface with water-based droplet directional transport.

[0082] Example 1

[0083] The present application has a Fe3O4-PDMS photothermal response microcolumnar surface preparation method with lubricating oil directional transport, which is specifically implemented according to the following steps:

[0084] Step 1, design a biomimetic pitcher-rice leaf composite structure;

[0085] Step 2, laser processing of the biomimetic pitcher-rice leaf composite structure on the metal surface;

[0086] Step 3, Fe3O4-PDMS mixture preparation and coating;

[0087] Step 4, microcolumnar structure preparation;

[0088] Step 5, silane coupling agent treatment;

[0089] Step 6, nanoparticle modification, to obtain a Fe3O4-PDMS photothermal response microcolumnar surface.

[0090] Example 2

[0091] The selected test piece for preparing the Fe3O4-PDMS photothermal response microcolumnar surface is Ti6Al4V, and a titanium alloy test piece with a diameter of Φ30×5 (mm) is selected. Specific embodiments of the Fe3O4-PDMS photothermal response microcolumnar surface with lubricating oil directional transport.

[0092] Step 1, design a biomimetic pitcher-rice leaf composite structure;

[0093] Step 1 is specifically implemented according to the following steps:

[0094] Step 1.1, the biomimetic pitcher-rice leaf composite structure is composed of a "human" shaped structure of a biomimetic pitcher and a linear structure of a biomimetic rice leaf. The composite structure is centrally symmetric, and the upper and lower structures are composed of the "human" shaped track of the biomimetic pitcher. The upper part and the lower part are connected by the linear structure of the biomimetic rice leaf to form a composite structure that can be used for droplet directional transport;

[0095] Step 1.2, the linear width Wd of the biomimetic rice leaf connecting structure is 20 μm, the linear spacing d is 0.15 mm, the linear track angle Dα is 5°, and the linear track length W1 is 3 mm;

[0096] Step 1.3, the biomimetic pitcher plant track width Wz is 1 mm, the single biomimetic pitcher plant structure linear width b1 is 100 μm, the middle distance b2 is 100 μm, the inclination angle Zα is 30°, a plurality of groups of biomimetic pitcher plant structures are arranged along the length direction at equal intervals, and the arrangement interval h is 500 μm.

[0097] Step 2, laser processing a biomimetic pitcher plant-rice leaf composite structure on the titanium alloy surface;

[0098] Step 2 is specifically implemented according to the following steps:

[0099] Step 2.1, polishing the titanium alloy test piece to remove the surface oxide layer;

[0100] Step 2.2, the test piece obtained in step 2.1 is ultrasonically cleaned with anhydrous ethanol for 5 min to remove surface lipids and organic matter, and the test piece surface is rinsed with deionized water to remove residual anhydrous ethanol on the surface. After the surface is dried, it is ready for use;

[0101] Step 2.3, place the test piece horizontally, and after marking the laser processing area on the surface of the test piece, start marking the biomimetic pitcher plant-rice leaf composite structure. The laser processing process is set as follows: laser power is 20 W, laser frequency is 20 KHz, pulse width is 300 ns, processing speed is 50 mm / s, and processing times is 3 times;

[0102] Step 2.4, the test piece surface marked with the biomimetic pitcher plant-rice leaf composite structure is polished again using 1000# sandpaper to remove burrs generated by surface laser processing, and then surface polishing treatment is performed. The test piece surface is rinsed with deionized water and then placed in anhydrous ethanol for ultrasonic cleaning for 5 min to remove residual metal debris and polishing abrasive particles on the test piece surface.

[0103] Step 3, Fe3O4-PDMS mixture preparation and coating;

[0104] Step 3 is specifically implemented according to the following steps:

[0105] Step 3.1, mixing polydimethylsiloxane and curing agent at a mass ratio of 10:1 and stirring uniformly to obtain a PDMS mixture;

[0106] Step 3.2, mixing Fe3O4 particles and the PDMS mixture obtained in step 3.1 at a mass ratio of 1:1, and uniformly mixing the Fe3O4 particles and the PDMS mixture by stirring to obtain a Fe3O4-PDMS mixture. The particle size of the Fe3O4 particles is one or more of 100 nm-10 μm particle size microparticles;

[0107] Step 3.3, using a four-sided film applicator to evenly scrape the Fe3O4-PDMS mixture on the surface of the test piece, so that the biomimetic pitcher-rice leaf composite structure is filled with Fe3O4-PDMS mixture, and the Fe3O4-PDMS mixture in other areas of the surface is cleaned and wiped off, so that only the biomimetic pitcher-rice leaf composite structure is filled.

[0108] Step 4, micro-column structure preparation

[0109] Step 4 is implemented according to the following steps:

[0110] Step 4.1, the fluorination liquid is composed of anhydrous ethanol and fluorosilane, the volume fraction of fluorosilane is 1%, and the fluorosilane is trichloro-tridecafluoro-n-octylsilane;

[0111] Step 4.2, place the glass slide in the fluorination liquid and soak for 5 min to complete the low surface energy treatment;

[0112] Step 4.3, use copper foil as a gasket to support the low surface energy treated glass slide of step 4.2 on the surface of the test piece obtained in step 3.3, and the thickness of the copper foil gasket is 100 μm;

[0113] Step 4.4, place the structure obtained in step 4.3 horizontally on the surface of a magnet, and stand for 1 min to obtain a micro-column structure under the guidance of a magnetic field, and the magnet is of N52 grade;

[0114] Step 4.5, place the micro-column structure sample of step 4.4 and the magnet together in a forced air drying oven for curing treatment, the curing temperature is 70°C, and the curing time is 3 h, and the Fe3O4-PDMS micro-column surface curing is completed.

[0115] Step 5, silane coupling agent treatment;

[0116] Step 5 is implemented according to the following steps:

[0117] Step 5.1, the KH-550 ethanol solution is composed of KH-550 silane coupling agent and anhydrous ethanol, and the mass ratio of KH-550 silane coupling agent is 1%;

[0118] Step 5.2, immerse the Fe3O4-PDMS micro-column surface test piece obtained in step 4.5 in the KH-550 ethanol solution, the temperature is 20°C, and the soaking time is 5 min;

[0119] Step 5.3, place the surface obtained in step 5.2 in a temperature environment of 20-25°C for 10-20 h to complete the silane coupling agent treatment.

[0120] Step 6, nanoparticle modification, to obtain a Fe3O4-PDMS photothermal response micro-column surface.

[0121] Step 6 is specifically implemented according to the following steps:

[0122] Step 6.1, the nanoparticle modification solution is composed of SiO2 nanoparticles and anhydrous ethanol, the mass fraction of SiO2 nanoparticles is 1%, the particle size of SiO2 nanoparticles is 10 nm, after mixing SiO2 nanoparticles and anhydrous ethanol, the temperature is set to 40-60℃, and magnetic stirring is performed at a speed of 200 r / min for 5 min to complete the preparation of the nanoparticle modification solution;

[0123] Step 6.2, the test piece treated by the silane coupling agent in step 5.3 is horizontally placed in the nanoparticle modification solution and soaked for 1 min, and then taken out and left to stand for 10 min;

[0124] Step 6.3, the test piece in step 6.2 is horizontally placed in the nanoparticle modification solution and soaked for 5 min, and then taken out and left to stand for 1 h to obtain a Fe3O4-PDMS photothermal responsive microcolumn surface with directional transport of lubricating oil;

[0125] Step 6.4, the surface of the test piece in step 6.3 is infiltrated with 200 μL of lubricating oil, and the lubricating oil is PFPE lubricating oil to obtain a Fe3O4-PDMS photothermal responsive microcolumn surface with directional transport of water-based droplets.

[0126] Example 3

[0127] The test piece for preparing the Fe3O4-PDMS photothermal responsive microcolumn surface is Ti6Al4V, and a Φ30*5 (mm) copper test piece is selected. A specific embodiment of the Fe3O4-PDMS photothermal responsive microcolumn surface with directional transport of lubricating oil.

[0128] Step 1, design of a biomimetic pitcher-rice leaf composite structure;

[0129] Step 1 is specifically implemented according to the following steps:

[0130] Step 1.1, the biomimetic pitcher-rice leaf composite structure is composed of a "human" shaped structure of a biomimetic pitcher and a linear structure of a biomimetic rice leaf. The composite structure is centrally symmetrically arranged, and the upper and lower structures are composed of the "human" shaped track of the biomimetic pitcher, and the upper part and the lower part are connected by the linear structure of the biomimetic rice leaf to form a composite structure that can be used for directional transport of droplets;

[0131] Step 1.2, the linear width Wd of the biomimetic rice leaf connecting structure is 80 μm, the linear spacing d is 0.5 mm, the linear track angle Dα is 5°, and the linear track length W1 is 3 mm;

[0132] Step 1.3, the biomimetic pitcher plant track width Wz is 2 mm, the single biomimetic pitcher plant structure linear width b1 is 150 μm, the middle distance b2 is 200 μm, the inclination angle Zα is 90°, a plurality of groups of biomimetic pitcher plant structures are arranged at equal intervals along the length direction, and the arrangement interval h is 700 μm.

[0133] Step 2, laser processing of a biomimetic pitcher plant-rice leaf composite structure on a copper surface;

[0134] Step 2 is implemented according to the following steps:

[0135] Step 2.1, polishing the metal test piece to remove the surface oxide layer, the metal test piece being one of titanium alloy, copper, steel and aluminum alloy;

[0136] Step 2.2, ultrasonic cleaning the test piece obtained in step 2.1 with anhydrous ethanol for 10 min to remove surface lipids and organic matter, rinsing the test piece surface with deionized water to remove residual anhydrous ethanol on the surface, and drying the surface for standby;

[0137] Step 2.3, placing the test piece horizontally, marking the biomimetic pitcher plant-rice leaf composite structure after marking the laser processing area on the surface of the test piece, setting the laser power to 20 W, the laser frequency to 20 KHz, the pulse width to 100 ns, the processing speed to 50 mm / s, and the processing number to 1 time during the laser processing process;

[0138] Step 2.4, re-polishing the test piece surface marked with the biomimetic pitcher plant-rice leaf composite structure using 2000# sandpaper to remove burrs generated by the surface laser processing, then performing surface polishing treatment, rinsing the test piece surface with deionized water, and then placing it in anhydrous ethanol for ultrasonic cleaning for 5 min to remove residual metal debris and polishing abrasive particles on the test piece surface.

[0139] Step 3, Fe3O4-PDMS mixture preparation and coating;

[0140] Step 3 is implemented according to the following steps:

[0141] Step 3.1, mixing polydimethylsiloxane and a curing agent at a mass ratio of 5:1 and stirring uniformly to obtain a PDMS mixture;

[0142] Step 3.2, mixing Fe3O4 particles and the PDMS mixture obtained in step 3.1 at a mass ratio of 0.7:1, fully mixing the Fe3O4 particles and the PDMS mixture by stirring to obtain a Fe3O4-PDMS mixture, the particle size of the Fe3O4 particles being one or more of 1 μm particle size microparticles;

[0143] Step 3.3, using a four-sided film applicator to evenly scrape the Fe3O4-PDMS mixture on the surface of the test piece, so that the biomimetic pitcher-rice leaf composite structure is filled with Fe3O4-PDMS mixture, and the Fe3O4-PDMS mixture in other areas of the surface is cleaned and wiped off, so that only the biomimetic pitcher-rice leaf composite structure is filled.

[0144] Step 4, micro-column structure preparation

[0145] Step 4 is implemented according to the following steps:

[0146] Step 4.1, the fluorination liquid is composed of anhydrous ethanol and fluorosilane, the volume fraction of fluorosilane is 1%, and the fluorosilane is 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane;

[0147] Step 4.2, place the glass slide in the fluorination liquid and soak for 10 min, and complete the low surface energy treatment;

[0148] Step 4.3, use copper foil as a gasket to support the low surface energy treated glass slide of step 4.2 on the surface of the test piece obtained in step 3.3, and the thickness of the copper foil gasket is 400 μm;

[0149] Step 4.4, place the structure obtained in step 4.3 horizontally on the surface of a magnet, and stand for 5 min to obtain a micro-column structure under the guidance of a magnetic field, and the magnet is of N42 grade;

[0150] Step 4.5, place the micro-column structure sample of step 4.4 and the magnet together in a forced air drying oven for curing treatment, the curing temperature is 100°C, and the curing time is 1 h, and the Fe3O4-PDMS micro-column surface curing is completed.

[0151] Step 5, silane coupling agent treatment;

[0152] Step 5 is implemented according to the following steps:

[0153] Step 5.1, the KH-550 ethanol solution is composed of KH-550 silane coupling agent and anhydrous ethanol, and the mass ratio of KH-550 silane coupling agent is 1%;

[0154] Step 5.2, immerse the Fe3O4-PDMS micro-column surface test piece obtained in step 4.5 in the KH-550 ethanol solution, the temperature is 25°C, and the soaking time is 5 min;

[0155] Step 5.3, place the surface obtained in step 5.2 in a temperature environment of 25°C, and incubate for 10 h to complete the silane coupling agent treatment.

[0156] Step 6, nanoparticle modification, to obtain a Fe3O4-PDMS photothermal response micro-column surface.

[0157] Step 6 is specifically implemented according to the following steps:

[0158] Step 6.1, the nanoparticle modification solution is composed of SiO2 nanoparticles and anhydrous ethanol, the mass fraction of SiO2 nanoparticles is 5%, the particle size of SiO2 nanoparticles is 50 nm, after mixing SiO2 nanoparticles and anhydrous ethanol, the temperature is set to 60°C, and magnetic stirring is performed at a speed of 400 r / min for 10 min to complete the preparation of the nanoparticle modification solution;

[0159] Step 6.2, the test piece treated by the silane coupling agent in step 5.3 is horizontally placed in the nanoparticle modification solution and soaked for 5 min, and then taken out and left to stand for 20 min;

[0160] Step 6.3, the test piece in step 6.2 is horizontally placed in the nanoparticle modification solution and soaked for 5 min, and then taken out and left to stand for 2 h to obtain a Fe3O4-PDMS photothermal responsive microcolumn surface with directional transport of lubricating oil;

[0161] Step 6.4, the surface of the test piece in step 6.3 is infiltrated with 400 μL of lubricating oil, and the lubricating oil is PAO2 lubricating oil to obtain a Fe3O4-PDMS photothermal responsive microcolumn surface with directional transport of water-based droplets.

Claims

1. A method for preparing Fe304-PDMS photo-thermal responsive micro-pillar surface with directional transport of lubricating oil, characterized in that, Specifically according to the following steps: Step 1, design a biomimetic pitcher-rice leaf composite structure; The step 1 is specifically implemented according to the following steps: Step 1.1, the biomimetic pitcher-rice leaf composite structure is composed of two parts of the "human" shape structure of the biomimetic pitcher and the linear structure of the biomimetic rice liquid, and the center is symmetrically arranged, the upper and lower structures are composed of the "human" shape track of the biomimetic pitcher, and the upper and lower parts are connected by the linear structure of the biomimetic rice leaf to form a composite structure for directional transport of liquid drops; Step 1.2, the linear width Wd of the biomimetic rice leaf connecting structure is 20-80 μm, the linear spacing d is 0.1-0.5 mm, the linear track angle Dα is 0-5°, and the linear track length W1 is 1-3 mm; Step 1.3, the width Wz of the biomimetic pitcher track is 0.5-2 mm, the linear width b1 of a single biomimetic pitcher structure is 100-150 μm, the spacing b2 between the two opposite single biomimetic pitcher structures is 50-200 μm, the inclination angle Zα of a single biomimetic pitcher structure is 30-90°, a plurality of biomimetic pitcher structures are arranged at equal intervals along the length direction, and the spacing h between the adjacent two single biomimetic pitcher structures is 500-700 μm; Step 2, laser processing of biomimetic pitcher-rice leaf composite structure on metal surface; Step 3, Fe3O4-PDMS mixture preparation and coating; The step 3 is specifically implemented according to the following steps: Step 3.1, mixing and stirring polydimethylsiloxane and curing agent at a mass ratio of 5:1-10:1 to obtain a PDMS mixture; Step 3.2, mixing Fe3O4 particles and the PDMS mixture obtained in step 3.1 at a mass ratio of 0.7:1-1:1, and fully mixing the Fe3O4 particles and the PDMS mixture by stirring to obtain a Fe3O4-PDMS mixture, wherein the particle size of the Fe3O4 particles is one or more of 100 nm-10 μm; Step 3.3, uniformly scraping the Fe3O4-PDMS mixture on the surface of the test piece to fill the Fe3O4-PDMS mixture in the biomimetic pitcher-rice leaf composite structure, and cleaning and wiping the Fe3O4-PDMS mixture in other areas of the surface to make the surface only filled with the biomimetic pitcher-rice leaf composite structure; Step 4, micro-column structure preparation; Step 5, silane coupling agent treatment; Step 6, nanoparticle modification, to obtain a Fe3O4-PDMS photothermal response micro-column surface.

2. The Fe304-PDMS photothermal responsive microcylinder surface preparation method with directional delivery of lubricating oil according to claim 1, characterized in that, The step 2 is specifically implemented according to the following steps: Step 2.1, polishing the metal test piece to remove the surface oxide layer, wherein the metal test piece is any one of titanium alloy, copper, steel and aluminum alloy; Step 2.2, ultrasonic cleaning the metal test piece obtained in step 2.1 with anhydrous ethanol for 5-10 min to remove surface lipids and organic matter, then rinsing the surface of the metal test piece with deionized water to remove residual anhydrous ethanol, and drying the surface for standby; Step 2.3, the metal sample is placed horizontally, and after marking the laser processing area on the surface of the sample, the biomimetic nepenthes-rice leaf composite structure is marked, and the laser processing process is set as follows: laser power 20-30 W, laser frequency 20-50 KHz, pulse width 100-300 ns, processing speed 50-100 mm / s, and processing times 1-3 times; Step 2.4, the surface of the metal sample marked with the biomimetic nepenthes-rice leaf composite structure is polished again using 1000-2000# sandpaper to remove burrs generated by laser processing on the surface, and then surface polishing treatment is performed, the surface of the metal sample is washed with deionized water, and then placed in anhydrous ethanol for ultrasonic cleaning for 5-10 min to remove residual metal debris and polishing abrasive particles on the surface of the sample.

3. The Fe304-PDMS photothermal responsive microcylinder surface preparation method with directional delivery of lubricating oil according to claim 2, characterized in that, The step 4 is specifically implemented according to the following steps: Step 4.1 The fluorination solution is prepared by mixing anhydrous ethanol with a fluorosilane, the fluorosilane being present in a volume fraction of 1% to 5%, the fluorosilane being trichlorotri-decafluoro-n-octylsilane triethoxy-1H, 1H, 2H, 2H-tridecafluoro-n-octylsilane one or more of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane; Step 4.2, place the glass slide in the fluorination liquid of step 4.1 and soak for 5-10 min to complete the low surface energy treatment; Step 4.3, use copper foil as a gasket to support the glass slide treated with low surface energy in step 4.2 on the surface of the sample obtained in step 3, and the thickness of the copper foil gasket is 100-400 μm; Step 4.4, place the structure obtained in step 4.3 horizontally on the surface of a magnet, and stand for 1-5 min to obtain a microcolumn structure under the guidance of a magnetic field, and the magnet is any one of N37, N42, and N52; Step 4.5, place the microcolumn structure sample obtained in step 4.4 and the magnet together in a forced air drying oven for curing treatment, the curing temperature is 70-100 ℃, and the curing time is 1-3 h to complete the surface curing of the Fe3O4-PDMS microcolumn.

4. The Fe304-PDMS photothermal responsive microcylinder surface preparation method with directional delivery of lubricating oil according to claim 3, characterized in that, The step 5 is specifically implemented according to the following steps: Step 5.1, mix KH-550 silane coupling agent and anhydrous ethanol to prepare a KH-550 ethanol solution, and the mass ratio of KH-550 silane coupling agent is 1%-5%; Step 5.2, immerse the surface sample of the Fe3O4-PDMS microcolumn obtained in step 4.5 in the KH-550 ethanol solution obtained in step 5.1, and the temperature is 20-25 ℃, and the soaking time is 1-5 min; Step 5.3, place the surface sample obtained in step 5.2 in a temperature environment of 20-25 ℃ for 10-20 h to complete the silane coupling agent treatment.

5. The Fe304-PDMS photothermal responsive microcylinder surface preparation method with directional delivery of lubricating oil according to claim 4, characterized in that, The step 6 is specifically implemented according to the following steps: Step 6.1, mix SiO2 nanoparticles and anhydrous ethanol to form a nanoparticle modification liquid, the mass fraction of SiO2 nanoparticles is 1%-5%, and the particle size of SiO2 nanoparticles is 10-50 nm, mix SiO2 nanoparticles and anhydrous ethanol, set the temperature to 40-60 ℃, and magnetically stir at a speed of 200-400 r / min for 5-10 min to complete the preparation of the nanoparticle modification liquid; Step 6.2, place the sample treated with the silane coupling agent in step 5 horizontally in the nanoparticle modification liquid, soak for 1-5 min, and stand for 10-20 min after taking out. Step 6.3, the test piece after step 6.2 is placed horizontally in the nanoparticle modification solution again, soaked for 1-5 min, and then taken out and placed for 1-2 h to obtain a Fe3O4-PDMS photothermal responsive microcolumn surface with directional transport of lubricating oil; Step 6.4, the surface of the test piece after step 6.3 is infiltrated with lubricating oil, the amount of lubricating oil is 200-400 μL, and the lubricating oil is one or more of PAO2, PAO4 and PFPE lubricating oil, to obtain a Fe3O4-PDMS photothermal responsive microcolumn surface with directional transport of water-based droplets.

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