Magnetically responsive self-supplementing lubricating coating as well as preparation method and application thereof

Abstract

The invention provides a self-supplementing lubricating coating with magnetic response as well as a preparation method and application of the self-supplementing lubricating coating. The self-supplementing lubricating coating comprises a lubricant storage layer used for storing a lubricant; the magnetic response deformation layer is positioned on the lubricant storage layer and is used for responding to external magnetic field stimulation to extrude the lubricant in the lubricant storage layer; the lubricating anti-scale layer is positioned on the magnetic response deformation layer and is used for stabilizing and spreading a lubricant which is transmitted to the surface of the lubricating anti-scale layer through an internal pore channel of the magnetic response deformation layer; the lubricant storage layer is made of a porous polymer material, the magnetic response deformation layer is a polysiloxane elastomer doped with magnetic particles, and the lubricating anti-scaling layer is of a hydrophobic rough micro-nano structure; the magnetic response deformation layer has a taper hole array structure. The self-supplementing lubricating coating can deform under the stimulation of an external magnetic field, so that a lubricant stored in the coating is slowly released, and the long-term efficient scale prevention of the lubricating coating in a complex fluid environment is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and specifically comprises a magnetically responsive self-replenishing lubricating coating, a preparation method thereof, and an application thereof. Background Art

[0002] Interfacial interactions play an important role in many aqueous processes, such as catalytic reactions, corrosion, and scaling. In particular, scaling processes can deposit on almost all surfaces. The scaling process can occur through the formation of mineral crystals in the bulk solution or through surface-induced heterogeneous nucleation of mineral crystals. The formation of scale can have an adverse effect on many production and living scenarios, such as oil collection and heat exchangers. For example, in the oil and gas industry, in order to improve oil recovery efficiency, seawater injection is often used. At this time, the alkaline earth metal ions in the formation water will form sulfate scale with the sulfate ions in the oil. Scale deposition and continued thickening will cause the inner diameter of the pipeline to decrease and block flow, reduce production capacity, and even cause the well to shut down. In addition, valve blockage and failure will bring huge safety hazards and even cause risks such as explosions.

[0003] At present, the treatment methods for scale in life and industrial production mainly adopt two types of means: physical mechanical removal and chemical inhibitor prevention. However, these means are not only costly, energy-intensive, and environmentally polluting, but also have very limited anti-scaling and descaling effects. As one of the commonly used anti-scaling strategies, coating technology has the characteristics of simple construction, strong versatility, long life, low cost, and environmental friendliness. As a new coating technology, lubricating coatings have shown potential application prospects in the fields of anti-fouling. Varanasi et al. from the Massachusetts Institute of Technology in the United States obtained nanostructures by etching the surface of silicon wafers and then immersed the surface in silicone oil. This layer of silicone oil not only reduced the nucleation rate of mineral crystals, but also reduced the adhesion of mineral crystals deposited on the surface. The mineral crystals can be washed away under low-flow water (Advanced Materials Interfaces, 2014, 1 (2), 1300068). Subsequently, Charpentier et al. from the University of Leeds in the United Kingdom used the electrodeposition method to modify porous polypyrrole on stainless steel and infused ionic liquid to form a lubricating surface for anti-scaling (ACS Omega, 2019, 4, 79). Bertran et al. at the State University of Campinas, Brazil, infused a perfluorinated lubricant into a linear structure of fluorinated polyaniline, forming a liquid film to prevent scale from adhering to the surface (Journal of Colloid and Interface Science, 2015, 444, 81). Under static conditions, these studies have achieved excellent anti-scaling effects. However, when lubricating coatings are used in complex environments, such as flow conditions, the lubricant is often lost due to the coating's own instability or changes in the external environment, resulting in a loss of the coating's anti-scaling properties. Therefore, it is particularly important to develop a coating that can provide stable lubrication and maintain long-term dynamic anti-scaling properties. Summary of the Invention

[0004] To address the aforementioned issues with the existing technology, the first objective of the present invention is to provide a magnetically responsive, self-replenishing lubricating coating. This self-replenishing lubricating coating can deform in response to an external magnetic field, slowly releasing lubricant stored within the coating. This enables on-demand lubricant replenishment on the coating surface, maintaining long-term, efficient anti-fouling properties in complex fluid environments.

[0005] The second object of the present invention is to provide a method for preparing the self-replenishing lubricating coating as described above.

[0006] The third object of the present invention is to provide an application of the self-replenishing lubricating coating in oil field development and transportation.

[0007] To achieve the above first object, the technical solution adopted by the present invention includes:

[0008] The present invention discloses a magnetically responsive self-replenishing lubricating coating, the self-replenishing lubricating coating comprising

[0009] a lubricant storage layer, used for storing lubricant;

[0010] a magnetically responsive deformation layer located on the lubricant storage layer, configured to squeeze the lubricant in the lubricant storage layer in response to an external magnetic field stimulus; and

[0011] A lubricating anti-fouling layer located on the magnetically responsive deformation layer, for stabilizing and spreading the lubricant transferred to the surface of the lubricating anti-fouling layer through the internal pores of the magnetically responsive deformation layer;

[0012] The lubricant storage layer is a porous polymer material, the magnetic response deformation layer is a polysiloxane elastomer doped with magnetic particles, and the lubricating anti-fouling layer is a hydrophobic rough micro-nano structure;

[0013] The magnetically responsive deformation layer has a cone hole array structure.

[0014] Inspired by the fact that glands on the surface of earthworms release lubricants under external mechanical stimulation, the present invention designs and prepares a magnetically responsive self-replenishing lubricating coating. This self-replenishing lubricating coating can slowly release the lubricant stored inside the coating under the stimulation of an external magnetic field, thereby achieving on-demand replenishment of the lubricant on the coating surface, thereby maintaining the long-term stability of the lubricating coating and being suitable for complex fluid environments.

[0015] In the early stage of scale prevention, the self-replenishing lubricating coating can effectively reduce the deposition and adhesion of scale by using the lubricant impregnated in the lubricating anti-scale layer itself. With the influence of factors such as evaporation, wetting ridges, and liquid shear, the lubricant impregnated in the lubricating anti-scale layer itself is severely lost. At this time, the magnetically responsive deformation layer can be deformed with the help of an external magnetic field stimulation. After deformation, the lubricant storage layer is squeezed, so that the lubricant stored in the lubricant storage layer is transmitted upward to the lubricating anti-scale layer through the tapered hole array structure of the magnetically responsive deformation layer, thereby realizing on-demand replenishment of the lubricant on the coating surface. The released lubricant can be stably spread under the special rough micro-nano structure of the lubricating anti-scale layer, thereby achieving long-term dynamic scale prevention on the entire coating surface.

[0016] Furthermore, the tapered hole array structure is a porous structure having tapered holes arranged in an array inside the magnetically responsive deformation layer.

[0017] Furthermore, the tapered hole penetrates the magnetically responsive deformation layer, wherein the tapered hole is formed by drilling a hole through the interface between the magnetically responsive deformation layer and the lubricating anti-fouling layer using a drilling device, and then exiting from the opposite side of the interface between the magnetically responsive deformation layer and the lubricating anti-fouling layer. The drilling device used can be a carbon dioxide laser marking machine. The diameter of the tapered hole formed on the interface between the magnetically responsive deformation layer and the lubricating anti-fouling layer is 450-850 μm, preferably 600-850 μm. Exemplarily, the diameter of the tapered hole can be 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, etc. The spacing between adjacent tapered holes is 1-12 mm. Exemplarily, the spacing between adjacent tapered holes can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, etc.

[0018] Furthermore, the tapered hole array structure may be a tapered hole array structure arranged in a polygonal array, such as a tapered hole array structure arranged in a quadrilateral array, a tapered hole array structure arranged in a pentagonal array, or a tapered hole array structure arranged in a hexagonal array.

[0019] Furthermore, the porous polymer material is a commercially available polymer sponge with a pore size of 50-300 μm. If the pore size is too small, it will be detrimental to the recovery of the surface lubricating layer.

[0020] Furthermore, the lubricant is selected from one or more of liquid paraffin, edible oil, silicone oil and perfluoropolyether-based lubricant;

[0021] The magnetic particles are selected from one or more of iron powder, ferroferric oxide nanoparticles, cobalt nanoparticles and neodymium iron boron particles.

[0022] Furthermore, the hydrophobic rough micro-nano structure contains nanoparticles;

[0023] The nanoparticles are selected from one or more of silicon dioxide particles, zinc oxide particles, titanium dioxide particles and boron nitride particles, and have a particle size of 1-50 μm. They can be purchased or synthesized by themselves.

[0024] Furthermore, the thickness of the lubricant storage layer is 1000-5000 μm. For example, the thickness of the lubricant storage layer may be 1000 μm, 2000 μm, 3000 μm, 4000 μm, 5000 μm, etc.; the thickness of the magnetic response deformation layer is 100-1000 μm. For example, the thickness of the magnetic response deformation layer may be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc., preferably 1000 μm. The thickness of the lubricating anti-fouling layer is 10-50 μm.

[0025] Furthermore, the thickness ratio of the lubricant storage layer, the magnetically responsive deformation layer and the lubricating anti-fouling layer is 150:20:1, which is more conducive to utilizing the deformation of the magnetically responsive deformation layer to squeeze the release of the lubricant in the lubricant storage layer.

[0026] To achieve the above second purpose, the technical solutions adopted by the present invention include:

[0027] The present invention discloses a method for preparing the self-replenishing lubricating coating as described above, comprising the following steps:

[0028] 1) mixing a polysiloxane elastomer and a cross-linking agent to obtain a prepolymer, adding magnetic particles to the prepolymer, and uniformly mixing to obtain a magnetic polysiloxane elastomer prepolymer liquid;

[0029] 2) coating a magnetic polysiloxane elastomer prepolymer solution on a substrate to form a coating film, then placing a porous polymer material on the coating film and drying and curing the film together, and removing the substrate after curing to obtain a lubricant storage layer and a magnetically responsive deformation layer;

[0030] 3) punching holes in the magnetically responsive deformation layer to form a conical hole array structure, then adding nanoparticles to the prepolymer to obtain a mixed solution, spraying the mixed solution on the surface of the magnetically responsive deformation layer, drying and curing to obtain a composite coating, and immersing the composite coating in a lubricant to obtain a self-replenishing lubricating coating.

[0031] Furthermore, the substrate is selected from substrates that do not react with the magnetic polysiloxane elastomer prepolymer liquid. For example, the substrate can be a silicon wafer, a polyethylene substrate, a polypropylene substrate, a polystyrene substrate, a polyvinyl chloride substrate, a polymethyl methacrylate substrate, or the like.

[0032] Furthermore, the curing temperature of step 2 and step 3 is 60-80° C., and the curing time is 1-12 hours.

[0033] Furthermore, the polysiloxane elastomer and cross-linking agent can be directly selected from the commercially available Dow Corning 184PDMS body and cross-linking agent combination, and are prepared at a mass ratio of 10:1;

[0034] The mass ratio of the prepolymer to the magnetic particles is 1-10:1; illustratively, the mass ratio of the prepolymer to the magnetic particles can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0035] The mass ratio of the prepolymer to the nanoparticles is 10:1.

[0036] To achieve the third objective, the present invention employs the following technical solutions:

[0037] The present invention discloses an application of the self-replenishing lubricating coating in oil field development and transportation.

[0038] Furthermore, the self-replenishing lubricating coating is applied to dynamic anti-scaling during oil field development and transportation.

[0039] Beneficial effects of the present invention:

[0040] The magnetically responsive self-replenishing lubricating coating provided by the present invention is inspired by the fact that the glands on the surface of earthworms release lubricants under external mechanical stimulation. The present invention designs and prepares a magnetically responsive self-replenishing lubricating coating. The self-replenishing lubricating coating can slowly release the lubricant stored inside the coating under the stimulation of an external magnetic field, thereby achieving on-demand replenishment of the lubricant on the coating surface, thereby maintaining the long-term stability of the lubricating coating and being suitable for complex fluid environments.

[0041] The magnetically responsive self-replenishing lubricating coating provided by the present invention has the characteristic of long-term inhibition of scale adhesion in pipelines. In a 168-hour test in a flowing supersaturated salt solution, the amount of scale deposited on the surface of the self-replenishing lubricating coating provided by the present invention was extremely small, with a minimum of 0.2 mg / cm 2 .

[0042] The self-replenishing lubricating coating of the present invention utilizes a stable, self-replenishing lubricant as an isolation layer to reduce scale deposition and adhesion, providing a long-term, dynamic anti-scaling strategy. This invention helps address the problem of scale deposits easily precipitating and adhering to pipe walls during pipeline transportation, disrupting normal production. This invention can be widely used in petrochemical transportation pipelines and wastewater treatment pipelines, reducing pipeline corrosion, extending pipeline life and production efficiency, and reducing treatment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] Figure 1 Scanning electron microscope images of the magnetically responsive self-replenishing lubricating coating of Example 1 are shown as a whole and as individual components.

[0045] Figure 2 The initial state of the magnetically responsive self-replenishing lubricating coating of Example 1, the sliding angle after the lubricating layer is lost, and the corresponding sliding angle after the lubricating layer is restored are shown.

[0046] Figure 3 The sliding angle change of the magnetically responsive self-replenishing lubricating coating of Example 1 after multiple loss-recovery cycle tests is shown. DETAILED DESCRIPTION

[0047] To more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. It should be understood that the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] In addition, unless otherwise specified, the raw materials used in the present invention can be obtained commercially, and any range recorded in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0049] Example 1

[0050] (1) The bulk of Dow Corning 184PDMS and a crosslinker were mixed at a mass ratio of 10:1 to obtain a prepolymer, and cobalt nanoparticles were added at a mass ratio of 1:1 to the prepolymer and mixed evenly. The air bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0051] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0052] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0053] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Conical holes are formed by laser ablation, and the power is controlled to obtain a conical hole array structure with a conical hole diameter of 650 μm and a spacing between adjacent conical holes of 8 mm.

[0054] (5) The bulk of Dow Corning 184PDMS and the crosslinker were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then silica particles were added at a mass ratio of the prepolymer to the silica particles of 10:1, mixed uniformly, and vacuumed to remove bubbles to obtain a mixed solution.

[0055] (6) Spray the mixed solution obtained in step 5 on the surface of the magnetically responsive deformation layer, place it in an oven at 80° C. and cure it for 1 hour to obtain a composite coating.

[0056] The composite coating prepared in step 6 was characterized using a scanning electron microscope. Figure 1The figure shows that after a series of preparation processes, a three-layer coating is obtained: a lubricating anti-fouling layer, a magnetically responsive deformation layer, and a lubricant storage layer. The rough structure of the lubricating anti-fouling layer is 20μm thick, the magnetically responsive deformation layer is about 400μm thick, the lubricant storage layer at the bottom has a pore size of about 300μm, and the silica particles in the lubricating anti-fouling layer are about 5μm in size.

[0057] (7) The composite coating obtained in step 6 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0058] In the rolling angle experiment, different test samples were placed on a rotatable mechanical turntable, the coating was fixed, the tilt angle was adjusted, 20 μL of deionized water dyed with methylene blue was dripped on the surface, and the rolling of the droplet was observed using a camera. The different test samples were: the first was directly tested using the self-replenishing lubricating coating prepared in step 7, recorded as the initial sample; the second was tested after wiping the surface lubricant with alcohol and dust-free paper and rinsing the surface lubricant in fast-flowing deionized water; the third was tested after the surface lubricant layer was restored in a 250 mT magnetic field, recorded as the replenished sample. The results are shown in [1]. Figure 2 , both the initial sample and the replenished sample showed good lubrication ability. In the same way, the surface lubricating layer of the self-replenishing lubricating coating was repeatedly depleted and replenished to observe its recovery ability, see Figure 3 , after repeating it 8 times, it still maintains a good recovery ability.

[0059] In the static anti-fouling experiment, the prepared magnetically responsive self-replenishing lubricating coating was placed in water, and a magnetic field of 250mT was applied to the water tank every 24 hours. The surface lubricant of the coating was replenished using an optical camera. It was found that the coating had a strong self-replenishing lubricant ability and could completely restore the lubrication performance. Under the stimulation of the magnetic field, a sufficient amount of lubricant could be squeezed to the coating surface. The rough structure of the lubricating anti-fouling layer could increase the hydrophobicity of the coating surface, promote the spreading of the lubricant on the surface, and provide capillary force and hydrophobic interaction to stabilize the lubricant on the surface.

[0060] The anti-scaling performance of the magnetically responsive self-replenishing lubricating coating was tested under dynamic conditions. Specifically, the magnetically responsive self-replenishing lubricating coating was placed in a flow cell connected to a peristaltic pump. The fluid was a 50 mM CaSO4 supersaturated solution. The flow rate was set at 200 mL / min. A 250 mT magnetic field was applied to the flow cell every 24 hours to replenish the lubricant on the coating surface. After 168 hours of observation using a scanning electron microscope, it was found that there was almost no scale crystal adhesion on the coating surface. Quantitative analysis of calcium by atomic emission spectroscopy revealed that the CaSO4 content on the coating surface was approximately 0.2 mg / cm3 after 168 hours of dynamic testing. 2, which proves that the magnetically responsive self-replenishing lubricating coating has good anti-fouling effect.

[0061] Example 2

[0062] (1) The bulk of Dow Corning 184PDMS and the crosslinking agent were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then ferrosoferric oxide particles were added at a mass ratio of 1:1 between the prepolymer and ferrosoferric oxide particles, and the mixture was mixed uniformly. The bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0063] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0064] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0065] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Conical holes are formed by laser ablation, and the power is controlled to obtain a conical hole array structure with a conical hole diameter of 450 μm and a spacing between adjacent conical holes of 6 mm.

[0066] (5) The bulk of Dow Corning 184PDMS and the crosslinker were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then silica particles were added at a mass ratio of the prepolymer to the silica particles of 10:1, mixed uniformly, and vacuumed to remove bubbles to obtain a mixed solution.

[0067] (6) Spraying the mixed solution obtained in step 5 on the surface of the magnetically responsive deformation layer, curing it at 80° C. for 1 h, and obtaining a composite coating.

[0068] After testing, the rough structure thickness of the lubricating anti-fouling layer is 20μm, the thickness of the magnetic response deformation layer is about 400μm, the pore size of the lubricant storage layer at the bottom is about 300μm, and the silica size in the lubricating anti-fouling layer is about 5μm.

[0069] (7) The composite coating obtained in step 6 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0070] In the static anti-fouling experiment, the prepared magnetically responsive self-replenishing lubricating coating was placed in water, and a magnetic field of 250mT was applied to the water tank every 24 hours. The surface lubricant of the coating was replenished using an optical camera. It was found that the coating had a strong self-replenishing lubricant ability and could completely restore the lubrication performance. Under the stimulation of the magnetic field, a sufficient amount of lubricant could be squeezed to the coating surface. The rough structure of the lubricating anti-fouling layer could increase the hydrophobicity of the coating surface, promote the spreading of the lubricant on the surface, and provide capillary force and hydrophobic interaction to stabilize the lubricant on the surface.

[0071] The anti-scaling performance of the magnetically responsive self-replenishing lubricating coating was tested under dynamic conditions. Specifically, the magnetically responsive self-replenishing lubricating coating was placed in a flow cell connected to a peristaltic pump. The fluid was a 50 mM CaSO4 supersaturated solution. The flow rate was set at 200 mL / min. A 300 mT magnetic field was applied to the flow cell every 24 hours to replenish the lubricant on the coating surface. After 168 hours of observation using a scanning electron microscope, it was found that there was almost no scale crystal adhesion on the coating surface. Quantitative analysis of calcium by atomic emission spectroscopy revealed that the CaSO4 content on the coating surface was approximately 1.6 mg / cm3 after 168 hours of dynamic testing. 2 , which proves that the magnetically responsive self-replenishing lubricating coating has good anti-fouling effect.

[0072] Example 3

[0073] (1) The bulk of Dow Corning 184PDMS and the crosslinking agent were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then iron powder was added at a mass ratio of 1:1 to the prepolymer and iron powder, and mixed uniformly. The air bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer liquid.

[0074] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0075] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0076] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Conical holes are formed by laser ablation, and the power is controlled to obtain a conical hole array structure with a conical hole diameter of 650 μm and a spacing between adjacent conical holes of 4 mm.

[0077] (5) The bulk of Dow Corning 184PDMS and the crosslinker were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then silica particles were added at a mass ratio of the prepolymer to the silica particles of 10:1, mixed uniformly, and vacuumed to remove bubbles to obtain a mixed solution.

[0078] (6) Spray the mixed solution obtained in step 5 on the surface of the magnetically responsive deformation layer, place it in an oven at 80° C. and cure it for 1 hour to obtain a composite coating.

[0079] After testing, the rough structure thickness of the lubricating anti-fouling layer is 20μm, the thickness of the magnetic response deformation layer is about 400μm, the pore size of the lubricant storage layer at the bottom is about 300μm, and the silica size in the lubricating anti-fouling layer is about 5μm.

[0080] (7) The composite coating obtained in step 6 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0081] In the static anti-fouling experiment, the prepared magnetically responsive self-replenishing lubricating coating was placed in water, and a magnetic field of 250mT was applied to the water tank every 24 hours. The surface lubricant of the coating was replenished using an optical camera. It was found that the coating had a strong self-replenishing lubricant ability and could completely restore the lubrication performance. Under the stimulation of the magnetic field, a sufficient amount of lubricant could be squeezed to the coating surface. The rough structure of the lubricating anti-fouling layer could increase the hydrophobicity of the coating surface, promote the spreading of the lubricant on the surface, and provide capillary force and hydrophobic interaction to stabilize the lubricant on the surface.

[0082] The anti-scaling performance of the magnetically responsive self-replenishing lubricating coating was tested under dynamic conditions. Specifically, the magnetically responsive self-replenishing lubricating coating was placed in a flow cell connected to a peristaltic pump. The fluid was a 50 mM CaSO4 supersaturated solution. The flow rate was set at 200 mL / min. A 250 mT magnetic field was applied to the flow cell every 24 hours to replenish the lubricant on the coating surface. After 168 hours of observation using a scanning electron microscope, it was found that there was almost no scale crystal adhesion on the coating surface. Quantitative analysis of calcium by atomic emission spectroscopy revealed that the CaSO4 content on the coating surface was approximately 2.3 mg / cm3 after 168 hours of dynamic testing. 2 , which proves that the magnetically responsive self-replenishing lubricating coating has good anti-fouling effect.

[0083] Comparative Example 1

[0084] (1) The bulk of Dow Corning 184PDMS and a crosslinker were mixed at a mass ratio of 10:1 to obtain a prepolymer, and cobalt nanoparticles were added at a mass ratio of 1:1 to the prepolymer and mixed evenly. The air bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0085] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0086] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0087] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Laser ablation is performed to form conical holes. The power is controlled to obtain a conical hole array structure with a conical hole diameter of 250 μm and an adjacent large hole spacing of 8 mm.

[0088] (5) The bulk of Dow Corning 184PDMS and the crosslinker were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then silica particles were added at a mass ratio of the prepolymer to the silica particles of 10:1, mixed uniformly, and vacuumed to remove bubbles to obtain a mixed solution.

[0089] (6) Spray the mixed solution obtained in step 5 on the surface of the magnetically responsive deformation layer, place it in an oven at 80° C. and cure it for 1 hour to obtain a composite coating.

[0090] (7) The composite coating obtained in step 6 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0091] In the static anti-fouling experiment, the prepared magnetically responsive self-replenishing lubricating coating was placed in water, and a magnetic field of 250mT was applied to the water tank every 24 hours. The surface lubricant of the coating was observed using an optical camera. It was found that its self-replenishing lubricant ability was poor and the lubricant could not spread across the entire coating surface. This is because the pore size of the internal structure of the coating is small, so the deformation under the action of the magnetic field is small, and the stored lubricant cannot be released in large quantities.

[0092] Comparative Example 2

[0093] (1) The bulk of Dow Corning 184PDMS and a crosslinker were mixed at a mass ratio of 10:1 to obtain a prepolymer, and cobalt nanoparticles were added at a mass ratio of 5:1 between the prepolymer and the cobalt nanoparticles, and the mixture was mixed evenly. The bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0094] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0095] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0096] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Conical holes are formed by laser ablation, and the power is controlled to obtain a conical hole array structure with a conical hole diameter of 650 μm and a spacing between adjacent conical holes of 8 mm.

[0097] (5) The bulk of Dow Corning 184PDMS and the crosslinker were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then silica particles were added at a mass ratio of the prepolymer to the silica particles of 10:1, mixed uniformly, and vacuumed to remove bubbles to obtain a mixed solution.

[0098] (6) Spray the mixed solution obtained in step 5 onto the surface of the magnetically responsive deformation layer where macropores are formed, and place the mixture in an oven at 80° C. for curing for 1 h to obtain a composite coating.

[0099] (7) The composite coating obtained in step 6 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0100] In the static anti-fouling experiment, the prepared magnetically responsive self-replenishing lubricating coating was placed in water, and a magnetic field of 250mT was applied to the water tank every 24 hours. The surface lubricant of the coating was observed using an optical camera. It was found that its self-replenishing lubricant ability was poor and the lubricant could not spread across the entire coating surface. This is because the content of cobalt nanoparticles inside the coating is relatively low, so the deformation under the action of the magnetic field is small, and the stored lubricant cannot be released in large quantities.

[0101] Comparative Example 3

[0102] (1) The bulk of Dow Corning 184PDMS and a crosslinker were mixed at a mass ratio of 10:1 to obtain a prepolymer, and cobalt nanoparticles were added at a mass ratio of 1:1 to the prepolymer and mixed evenly. The air bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0103] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0104] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0105] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Conical holes are formed by laser ablation, and the power is controlled to obtain a conical hole array structure with a conical hole diameter of 650 μm and an adjacent conical hole spacing of 8 mm to obtain a composite coating.

[0106] (5) The composite coating obtained in step 4 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0107] In the static anti-fouling experiment, the prepared magnetically responsive self-replenishing lubricating coating was placed in water, and a magnetic field of 250mT was applied to the water tank every 24 hours. The surface lubricant of the coating was observed using an optical camera. It was found that its self-replenishing lubricant ability was poor, and the lubricant could not spread on the coating surface. The released lubricant turned into oil droplets. This is because the coating surface has no rough structure and the coating has poor hydrophobicity.

[0108] Example 4

[0109] (1) The bulk of Dow Corning 184PDMS and a crosslinker were mixed at a mass ratio of 10:1 to obtain a prepolymer, and cobalt nanoparticles were added at a mass ratio of 1:1 to the prepolymer and mixed evenly. The air bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0110] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0111] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0112] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Laser ablation is performed to form conical holes. The power is controlled to obtain a conical hole array structure with a conical hole diameter of 650 μm and a spacing between adjacent conical holes of 10 mm.

[0113] (5) The bulk of Dow Corning 184PDMS and the crosslinker were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then silica particles were added at a mass ratio of the prepolymer to the silica particles of 10:1, mixed uniformly, and vacuumed to remove bubbles to obtain a mixed solution.

[0114] (6) Spray the mixed solution obtained in step 5 on the surface of the magnetically responsive deformation layer, place it in an oven at 80° C. and cure it for 1 hour to obtain a composite coating.

[0115] The composite coating prepared in step 6 was characterized using a scanning electron microscope. Figure 1The figure shows that after a series of preparation processes, a three-layer coating is obtained: a lubricating anti-fouling layer, a magnetically responsive deformation layer, and a lubricant storage layer. The rough structure of the lubricating anti-fouling layer is 20μm thick, the magnetically responsive deformation layer is about 400μm thick, the lubricant storage layer at the bottom has a pore size of about 300μm, and the silica in the lubricating anti-fouling layer is about 5μm in size.

[0116] (7) The composite coating obtained in step 6 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0117] In the static anti-fouling experiment, the prepared magnetically responsive self-replenishing lubricating coating was placed in water, and a magnetic field of 250mT was applied to the water tank every 24 hours. The surface lubricant of the coating was replenished using an optical camera. It was found that the coating had a strong self-replenishing lubricant ability and could completely restore the lubrication performance. Under the stimulation of the magnetic field, a sufficient amount of lubricant could be squeezed to the coating surface. The rough structure of the lubricating anti-fouling layer could increase the hydrophobicity of the coating surface, promote the spreading of the lubricant on the surface, and provide capillary force and hydrophobic interaction to stabilize the lubricant on the surface.

[0118] Example 5

[0119] (1) The bulk of Dow Corning 184PDMS and a crosslinker were mixed at a mass ratio of 10:1 to obtain a prepolymer, and cobalt nanoparticles were added at a mass ratio of 1:1 to the prepolymer and mixed evenly. The air bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0120] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0121] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0122] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Conical holes are formed by laser ablation, and the power is controlled to obtain a conical hole array structure with a conical hole diameter of 650 μm and a spacing between adjacent conical holes of 6 mm.

[0123] (5) The bulk of Dow Corning 184PDMS and the crosslinker were mixed uniformly at a mass ratio of 10:1 to obtain a prepolymer, and then silica particles were added at a mass ratio of the prepolymer to the silica particles of 10:1, mixed uniformly, and vacuumed to remove bubbles to obtain a mixed solution.

[0124] (6) Spray the mixed solution obtained in step 5 on the surface of the magnetically responsive deformation layer, place it in an oven at 80° C. and cure it for 1 hour to obtain a composite coating.

[0125] The composite coating prepared in step 6 was characterized using a scanning electron microscope. Figure 1 The figure shows that after a series of preparation processes, a three-layer coating is obtained: a lubricating anti-fouling layer, a magnetically responsive deformation layer, and a lubricant storage layer. The rough structure of the lubricating anti-fouling layer is 20μm thick, the magnetically responsive deformation layer is about 400μm thick, the lubricant storage layer at the bottom has a pore size of about 300μm, and the silica in the lubricating anti-fouling layer is about 5μm in size.

[0126] (7) The composite coating obtained in step 6 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0127] The anti-scaling performance of the magnetically responsive self-replenishing lubricating coating was tested under dynamic conditions. Specifically, the magnetically responsive self-replenishing lubricating coating was placed in a flow cell connected to a peristaltic pump. The fluid was a 50 mM CaSO4 supersaturated solution. The flow rate was set at 200 mL / min. The flow cell was placed in a 250 mT magnetic field to replenish the lubricant on the coating surface every 24 hours. After 168 hours of observation using a scanning electron microscope, it was found that there was almost no scale crystal adhesion on the coating surface. Quantitative analysis of calcium by atomic emission spectroscopy revealed that the CaSO4 content on the coating surface was approximately 0.98 mg / cm3 after 168 hours of dynamic testing. 2 .

[0128] Comparative Example 4

[0129] Refer to the preparation process of Example 5, the only difference is that it does not contain a lubricating anti-fouling layer.

[0130] (1) The bulk of Dow Corning 184PDMS and a crosslinker were mixed at a mass ratio of 10:1 to obtain a prepolymer, and cobalt nanoparticles were added at a mass ratio of 1:1 to the prepolymer and mixed evenly. The air bubbles were removed by vacuum to obtain a magnetic polysiloxane elastomer prepolymer solution.

[0131] (2) The magnetic polysiloxane elastomer prepolymer prepared in step 1 was coated on a polytetrafluoroethylene substrate using a scraper to form a coating film with a thickness of 1000 μm.

[0132] (3) Select a commercially available polymer sponge with a thickness of 3 mm, cut the polymer sponge into appropriate sizes, place it on the coating film in step 2, and put it in an oven for drying and curing. The curing condition is 80° C. for 1 hour.

[0133] (4) After curing, the polytetrafluoroethylene substrate is removed, and a carbon dioxide laser marking machine is used to drill holes on and penetrate the magnetically responsive deformation layer. Conical holes are formed by laser ablation, and the power is controlled to obtain a conical hole array structure with a conical hole diameter of 650 μm and a distance between adjacent conical holes of 6 mm, thereby obtaining a composite coating.

[0134] (5) Spraying the mixed solution obtained in step 4 on the surface of the magnetically responsive deformation layer, placing it in an oven at 80° C. for curing for 1 hour to obtain a composite coating.

[0135] (6) The composite coating obtained in step 5 is completely immersed in a perfluoropolyether lubricant, and a magnetically responsive self-replenishing lubricating coating is obtained after 24 hours.

[0136] The anti-scaling performance of the magnetically responsive self-replenishing lubricating coating was tested under dynamic conditions. Specifically, the magnetically responsive self-replenishing lubricating coating was placed in a flow cell connected to a peristaltic pump with a flow rate set at 200 mL / min. The flow cell was placed in a 250 mT magnetic field every 24 hours to replenish the lubricant on the coating surface. After 168 hours of observation using a scanning electron microscope, it was found that obvious scale crystals adhered to the coating surface. Quantitative analysis of calcium by atomic emission spectroscopy revealed that the CaSO4 content on the coating surface was approximately 17.99 mg / cm3 after 168 hours of testing under dynamic conditions. 2 .

[0137] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A magnetically responsive self-replenishing lubricating coating, characterized in that: The self-replenishing lubricating coating comprises a lubricant storage layer, used for storing lubricant; a magnetically responsive deformation layer located on the lubricant storage layer, configured to squeeze the lubricant in the lubricant storage layer in response to an external magnetic field stimulus; as well as A lubricating anti-fouling layer located on the magnetically responsive deformation layer, for stabilizing and spreading the lubricant transferred to the surface of the lubricating anti-fouling layer through the internal pores of the magnetically responsive deformation layer; The lubricant storage layer is a porous polymer material, the magnetic response deformation layer is a polysiloxane elastomer doped with magnetic particles, and the lubricating anti-fouling layer is a hydrophobic rough micro-nano structure; The magnetically responsive deformation layer has a cone hole array structure.

2. The self-replenishing lubricating coating according to claim 1, characterized in that The tapered hole array structure is a porous structure having tapered holes arranged in an array inside the magnetically responsive deformation layer; Preferably, the tapered hole penetrates the magnetically responsive deformable layer, wherein the tapered hole is formed by drilling a hole through the interface between the magnetically responsive deformable layer and the lubricating anti-fouling layer using a drilling device and exiting from the opposite side of the interface between the magnetically responsive deformable layer and the lubricating anti-fouling layer, the diameter of the tapered hole formed on the interface between the magnetically responsive deformable layer and the lubricating anti-fouling layer is 450-850 μm, and the spacing between adjacent tapered holes is 1-12 mm; Preferably, the porous polymer material is a polymer sponge with a pore size of 50-300 μm.

3. The self-replenishing lubricating coating according to claim 1, characterized in that The lubricant is selected from one or more of liquid paraffin, edible oil, silicone oil and perfluoropolyether-based lubricant; The magnetic particles are selected from one or more of iron powder, ferroferric oxide nanoparticles, cobalt nanoparticles and neodymium iron boron particles.

4. The self-replenishing lubricating coating according to claim 1, characterized in that The hydrophobic rough micro-nano structure contains nanoparticles; The nanoparticles are selected from one or more of silicon dioxide particles, zinc oxide particles, titanium dioxide particles and boron nitride particles, and have a particle size of 1-50 μm.

5. The self-replenishing lubricating coating according to claim 1, characterized in that The thickness of the lubricant storage layer is 1000-5000 μm, the thickness of the magnetic response deformation layer is 100-1000 μm, and the thickness of the lubricating anti-fouling layer is 10-50 μm; Preferably, the thickness ratio of the lubricant storage layer, the magnetically responsive deformation layer and the lubricating anti-fouling layer is 150:20:

1.

6. The method for preparing a self-replenishing lubricating coating according to any one of claims 1 to 5, characterized in that: The steps include: 1) mixing a polysiloxane elastomer and a cross-linking agent to obtain a prepolymer, adding magnetic particles to the prepolymer, and uniformly mixing to obtain a magnetic polysiloxane elastomer prepolymer liquid; 2) coating a magnetic polysiloxane elastomer prepolymer solution on a substrate to form a coating film, then placing a porous polymer material on the coating film and drying and curing the film together, and removing the substrate after curing to obtain a lubricant storage layer and a magnetically responsive deformation layer; 3) punching holes in the magnetically responsive deformation layer to form a conical hole array structure, then adding nanoparticles to the prepolymer to obtain a mixed solution, spraying the mixed solution on the surface of the magnetically responsive deformation layer, drying and curing to obtain a composite coating, and immersing the composite coating in a lubricant to obtain a self-replenishing lubricating coating.

7. The preparation method according to claim 6, characterized in that The curing temperature of step 2 and step 3 is 60-80° C., and the curing time is 1-12 hours.

8. The preparation method according to claim 6, characterized in that The mass ratio of polysiloxane elastomer to crosslinker is 10:1; The mass ratio of the prepolymer to the magnetic particles is 1-10:1; The mass ratio of the prepolymer to the nanoparticles is 10:

1.

9. Use of the self-replenishing lubricating coating according to any one of claims 1 to 5 in oil field development and transportation.

10. The use according to claim 9, characterized in that The self-replenishing lubricating coating is applied to dynamic scaling prevention during oil field development and transportation.

Images