Aerogel-reinforced antifouling coatings for ships and their preparation methods

Abstract

This invention belongs to the field of coating preparation technology and provides an aerogel-reinforced antifouling coating for ships and its preparation method. A fluorosilicone prepolymer is prepared by reacting perfluorohexyl ethyl acrylate with a silane coupling agent under the action of azobisisobutyronitrile (AIB). This prepolymer is then mixed with hydroxyl-terminated polydimethylsiloxane and PEEK nanofibers to obtain a resin matrix. An aerogel is prepared by hydrolyzing tetraethyl orthosilicate to form a SiO2 gel, followed by solvent replacement and perfluorinated surface modification. A chromium-based metal-organic framework composite material is prepared by hydrothermal method and then composited with an ionic liquid to obtain an ionic liquid composite additive. Microsphere additives are prepared by emulsion polymerization, and surface structure properties are further controlled by etching processes. The resin matrix, aerogel, ionic liquid composite additive, microsphere additive, and solvent are mixed to obtain the aerogel-reinforced antifouling coating for ships.

Description

Technical Field

[0001] This invention belongs to the field of coating preparation technology, and relates to aerogel-reinforced antifouling coatings for ships and their preparation methods. Background Technology

[0002] Marine antifouling coatings are a key material in marine engineering, one of their core functions being to prevent the attachment and growth of marine organisms on the ship's hull surface. The marine environment contains a large number of microorganisms, algae, barnacles, shellfish, and other organisms that secrete sticky substances or directly adhere to the ship's surface, forming a biofouling layer that increases navigational resistance. Therefore, the application of antifouling coatings is of great significance to the economy, safety, and ecological protection of ships. Traditional marine antifouling coatings achieve their antifouling function mainly through three mechanisms. The first is the physical barrier type, which works by constructing low surface energy or micro / nano-scale rough structures to reduce the contact area between organisms and the coating. The second is the chemical release type, which slowly releases biotoxic chemicals; however, with increasingly stringent environmental regulations, traditional highly toxic substances have been banned. The third is the biomimetic type.

[0003] Despite significant advancements in antifouling coating technology, it still faces substantial challenges in practical applications, primarily in durability and surface property degradation. In dynamic marine environments, coatings must simultaneously withstand multiple destructive factors, including physical friction, chemical erosion, and biological action. While the rigid network structure of traditional resin matrices provides initial strength, it is prone to microcracks under cyclic stress, which can propagate into macroscopic spalling. Furthermore, the surface functional layer of superhydrophobic coatings often lacks sufficient adhesion to the substrate, exposing the matrix under turbulent impacts or sand friction, making it susceptible to bioadhesion. Aerogel materials have attracted attention due to their unique three-dimensional network structure and high specific surface area. They can not only serve as a mechanical reinforcing phase to improve the coating's shear resistance, but their abundant porosity can also act as a carrier for bactericides, enabling controlled release. Through surface chemical modification, aerogels can simultaneously impart superhydrophobic properties and anti-bioadhesion capabilities to coatings. Therefore, the development of an aerogel-reinforced marine antifouling coating is of great significance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide aerogel-reinforced antifouling coatings for ships and their preparation method. First, a fluorosilicone prepolymer with excellent chemical stability and low surface energy is prepared as the resin matrix by combining perfluorination chemistry and silicon oxidation chemistry. Second, a superhydrophobic aerogel material is prepared through tetraethyl orthosilicate hydrolysis and perfluorination surface modification, enhancing the coating's anti-adhesion properties and mechanical stability. Third, a chromium-based metal-organic framework composite material is synthesized via a hydrothermal method and ionic liquid is introduced to prepare an ionic liquid composite additive with slow-release properties. Furthermore, a microsphere additive with a multi-level structure is prepared through emulsion polymerization combined with etching processes, further optimizing the surface function of the coating. Finally, the synergistic effect of the resin matrix, aerogel, ionic liquid composite additive, and microsphere additive endows the coating with antifouling properties and durability, thereby meeting the needs of practical production.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing an aerogel-reinforced antifouling coating for ships, the method comprising:

[0007] S1, Perfluorohexyl ethyl acrylate, silane coupling agent and azobisisobutyronitrile are mixed and reacted to obtain fluorosilicone prepolymer. Fluorosilicone prepolymer, hydroxyl-terminated PDMS, dibutyltin dilaurate and PEEK nanofibers are mixed to obtain resin matrix.

[0008] S2, mix tetraethyl orthosilicate, aqueous ethanol solution and aqueous ammonia solution and hydrolyze to obtain SiO2 gel, mix SiO2 gel with PDMS prepolymer to obtain wet gel, perform solvent replacement to obtain displacement gel, immerse displacement gel in per(xepin)fluorodecyltriethoxysilane aqueous ethanol solution to obtain aerogel;

[0009] S3, Chromium nitrate nonahydrate and terephthalic acid are dispersed in DMF aqueous solution and reacted to obtain product A. Then, product A is immersed in [BMIM]PF6 methanol solution to obtain ionic liquid composite additive.

[0010] S4, cyclohexane, Span80 and Tween80 are mixed, methyltriethoxysilane / quaternary ammonium salt solution is added, and then etched with acetic acid solution to obtain microsphere additive;

[0011] S5, a resin matrix, aerogel, ionic liquid composite additive, microsphere additive and solvent are mixed to obtain an aerogel-reinforced marine antifouling coating.

[0012] Specifically, it includes:

[0013] S1, Perfluorohexyl ethyl acrylate, silane coupling agent and azobisisobutyronitrile are mixed and reacted at the first temperature under a nitrogen atmosphere to obtain a fluorosilicone prepolymer. The fluorosilicone prepolymer, hydroxyl-terminated PDMS, dibutyltin dilaurate and PEEK nanofibers are mixed, stirred at the second temperature and ultrasonically dispersed to obtain a resin matrix.

[0014] S2, mix tetraethyl orthosilicate, aqueous ethanol solution and aqueous ammonia solution and hydrolyze to obtain SiO2 gel, mix SiO2 gel with PDMS prepolymer, adjust the temperature to the third temperature and stir to obtain wet gel, then perform solvent replacement to obtain displacement gel, immerse displacement gel in per(xepin)fluorodecyltriethoxysilane aqueous ethanol solution, adjust to the second temperature and stir, vacuum dry to obtain aerogel.

[0015] S3, Chromium nitrate nonahydrate and terephthalic acid are dispersed in DMF aqueous solution, and the temperature is adjusted to the fourth temperature for hydrothermal reaction to obtain product A. Then, product A is immersed in [BMIM]PF6 methanol solution and vacuum dried to obtain ionic liquid composite additive.

[0016] S4, cyclohexane, Span80 and Tween80 are mixed and adjusted to the specified pH with ammonia water, methyltriethoxysilane / quaternary ammonium salt solution is added and stirred, and then etched with acetic acid solution to obtain microsphere additive;

[0017] S5, a resin matrix, aerogel, ionic liquid composite additive, microsphere additive and solvent are mixed to obtain an aerogel-reinforced marine antifouling coating.

[0018] The synthesis of fluorosilicone prepolymers is based on the principle of free radical polymerization. Its core lies in activating the double bonds of fluorinated monomers through an initiator, triggering a chain growth reaction, while simultaneously introducing a silane coupling agent to achieve functional modification of the molecular chain. Perfluorohexyl ethyl acrylate (PFHEE) is the main monomer, and its acrylate group contains an unsaturated double bond. Azobisisobutyronitrile (AIB) acts as an initiator, generating free radicals upon heating. These free radicals attack the double bonds of PFHEE, initiating a chain growth reaction and forming a polymer backbone with a fluorocarbon chain as the main structure. The introduction of the silane coupling agent KH560 endows the prepolymer with key siloxane functional groups. The KH560 molecule contains two active groups: an epoxy group at one end and a methoxysilyl group at the other. Under high-temperature reaction conditions, the ring-opening epoxy group exposes hydroxyl groups. These hydroxyl groups can react with the free radicals at the ends of the PFHEE molecular chain or with active sites in the already formed polymer chain, thereby embedding the siloxane structural units into the fluorocarbon backbone. This chemical bonding not only achieves molecular-level hybridization of fluorocarbon and siloxane chains, but also provides the prepolymer with anchoring sites for subsequent reactions with inorganic fillers (such as silica aerogel) or organosilicon polymers (such as hydroxyl-terminated PDMS). Furthermore, the methoxysilane groups in KH560 can be converted into silanol groups during subsequent hydrolysis, providing chemical bonding capabilities for the interfacial bonding between the resin matrix and the reinforcing phase.

[0019] After the synthesis of the fluorosilicone prepolymer, it needs to be composited with hydroxyl-terminated polydimethylsiloxane (PDMS) through a condensation crosslinking reaction to construct a three-dimensional network structure, and a nano-reinforcing phase is introduced to improve mechanical properties. Hydroxyl-terminated PDMS is a linear organosilicon polymer with active hydroxyl groups at both ends of its molecular chains. These hydroxyl groups can undergo a condensation reaction with the methoxysilane groups in the fluorosilicone prepolymer under the action of a catalyst, connecting the linear fluorosilicone prepolymer and PDMS into a three-dimensional network structure. The formation of the crosslinked network endows the resin matrix with excellent elasticity and deformation recovery ability. The fluorocarbon segments provide compressive strength and low surface energy due to their rigid structure, while the flexible siloxane chains of PDMS absorb external stress through the coiling and slippage of the molecular chains, preventing brittle fracture. To further improve the impact resistance and wear resistance of the material, polyetheretherketone (PEEK) nanofibers were introduced as a reinforcing phase in the experiment. PEEK is a semi-crystalline high-performance engineering plastic, and its nanofibers are uniformly distributed in the resin matrix through high-energy ultrasonic dispersion. These fibers function through two mechanisms: first, they act as rigid fillers to directly bear external stress, consuming fracture energy through crack deflection and fiber pull-out effects; second, the abundant functional groups (such as ketone groups) on the fiber surface form hydrogen bonds or van der Waals forces with the polar groups in the resin matrix, enhancing the interfacial bonding strength.

[0020] Tetraethyl orthosilicate serves as the silicon source. Under alkaline conditions, the ethoxy group in its molecule undergoes a nucleophilic substitution reaction with water, gradually generating silicic acid monomers. Ammonia molecules, acting as a weak base, activate water molecules through deprotonation, accelerating the hydrolysis of the ethoxy group. The silicic acid monomers then connect through dehydration or de-alcoholization reactions, forming Si-O-Si bonds. In an alkaline environment, the condensation reaction tends to generate less branched linear structures, but with prolonged reaction time, these linear chains gradually form a nanonetwork with mesoporous structures through further cross-linking. After the silica gel is formed, polydimethylsiloxane (PDMS) prepolymer is introduced to construct an organic-inorganic hybrid network. The addition of PDMS achieves structural enhancement through a two-step mechanism: First, the silane-hydrogen bonds in the PDMS prepolymer undergo a condensation reaction with the silanol groups on the silica surface under heating conditions to form a covalently linked Si-O-Si bridging structure. This chemical bonding anchors the flexible PDMS segments onto the rigid silica framework, effectively alleviating external stress concentration and preventing brittle fracture. Second, the unreacted PDMS prepolymer fills the silica nanopores through physical penetration, forming an elastic support during the subsequent curing process, further enhancing the resilience of the aerogel.

[0021] Solvent replacement in the wet gel is a core step to prevent the collapse of the pore structure during drying. Ethanol is used to replace water molecules in the gel, utilizing the miscibility of ethanol and water to thoroughly remove residual moisture. This is followed by a transition to an ethanol-n-hexane mixed solvent to gradually reduce the system's polarity. Finally, pure n-hexane is used as the low surface tension solvent to complete the replacement. The choice of n-hexane is based on its low surface tension, which significantly reduces the capillary force exerted during evaporation, thereby minimizing the compression deformation of the pore structure. Furthermore, n-hexane has good compatibility with PDMS, avoiding phase separation between the solvent and polymer. After drying, the aerogel needs to be chemically modified to impart superhydrophobic properties. Perfluorodecyltriethoxysilane is used as a modifier; the ethoxysilane terminus in its molecule can undergo a condensation reaction with the silanol groups on the aerogel surface, forming a dense, low surface energy coating layer. This modification process not only reduces surface energy but also further refines the surface roughness through the perfluorinated chain. The chemical inertness of the fluorinated layer effectively resists the corrosion of oxidizing substances in the marine environment, extending the service life of the coating. The resin matrix and aerogel form a rigid-flexible interpenetrating structure through covalent bonds and physical entanglement. The condensation crosslinking of fluorosilicone prepolymer and PDMS endows the coating with elastic deformation capability, while the nanoporous framework of the aerogel absorbs external stress through crack deflection and energy dissipation mechanisms. This rigid-flexible synergy not only enhances the impact resistance of the coating but also inhibits phase separation through interfacial chemical compatibility. PEEK nanofibers, as a reinforcing phase, connect the resin and aerogel interface through a bridging effect. Their high modulus properties uniformly transfer local stress to the aerogel framework, preventing coating peeling caused by stress concentration. At the same time, after the aerogel surface is modified with fluorosilane, its low surface energy forms a chemically compatible interface with the fluorosilicone resin matrix, further strengthening the interfacial bonding strength and forming a dual mechanical-chemical synergy.

[0022] Chromium nitrate nonahydrate, used as a chromium source, undergoes a coordination reaction with the carboxylic acid groups of terephthalic acid. Terephthalic acid, acting as a bidentate ligand, deprotonates its two carboxylic acid groups, which then form stable coordination bonds with trivalent chromium ions via oxygen atoms, forming a motile pore structure (MOF). Each trivalent chromium ion coordinates with three terephthalic acid ligands, constructing a cage-like pore structure. The loading of the ionic liquid is based on the synergistic effect of capillary adsorption and surface interaction. During impregnation, the mesopores of the MOF draw the ionic liquid solution into the pores through capillary forces. The imidazole cations of the ionic liquid form stable bonds with the carboxylic acid groups in the MOF framework through electrostatic attraction and π-π stacking interactions, while the hexafluorophosphate anions fill the remaining space in the pores. After loading, vacuum drying removes the solvent, confining the ionic liquid molecules within the MOF pores, forming a composite system where physical adsorption and chemical bonding coexist. In seawater environments, the stability of the MOF framework is affected by factors such as pH and ionic strength. When the MOF coating comes into contact with seawater, chloride ions gradually replace hexafluorophosphate ions through ion exchange, disrupting the original electrostatic balance and causing imidazole cations to be slowly released from the pores. Simultaneously, sodium and magnesium ions in the seawater compete for coordination with trivalent chromium ions in the MOF framework, further weakening the framework structure and accelerating the diffusion and release of the ionic liquid. The released imidazole cations disrupt the charge balance of microbial cell membranes, leading to membrane potential disturbances and leakage of contents, thus prolonging the antifouling effect. Under the high salinity and weak alkalinity of seawater, the MOF framework needs to resist hydrolysis and ionic erosion. The strong coordination bond between trivalent chromium ions and carboxylic acid ligands endows the MOF with high hydrolysis resistance, while the hydrophobic ionic liquid layer can partially block direct contact between water molecules and the framework. Furthermore, the mesoporous structure of the MOF allows for the slow release of the ionic liquid, avoiding the burst release effect caused by excessively high concentrations in a short period, thereby reducing toxic effects on non-target organisms.

[0023] Span80 and Tween80, as nonionic surfactants, have molecular structures containing lipophilic hydrocarbon chains and hydrophilic polyethylene oxide chains. In a mixed system of oil and aqueous phases, they form an oil-in-water microemulsion. Methyltriethoxysilane, as a silicon source, undergoes stepwise hydrolysis and condensation of its ethoxy group in an alkaline aqueous core. Methyltriethoxysilane hydrolyzes to methylsilanetriol, and the hydroxyl groups carried by the hydrolysis product are highly reactive. Adjacent silanol molecules form Si-O-Si bonds through dehydration, initially generating linear or cyclic oligomeric siloxanes. In the microemulsion system, the spatial arrangement of oligomers is strictly restricted, forcing the molecules to adopt the lowest-energy configuration, namely a highly symmetrical cage structure. This structure arises from the synergistic effect of the tetrahedral bond angles and steric hindrance of the silicon-oxygen bonds: each silicon atom is connected to three bridging oxygen atoms and one methyl group, and eight silicon atoms are closed through oxygen bridging bonds to form a cubic framework with internal cavities. In the initial stage of hydrolysis of methyltriethoxysilane, a quaternary ammonium salt solution is added. Its cationic head group binds to the negatively charged silanol through electrostatic attraction, while the long-chain alkyl group embeds itself into the forming POSS organic shell through hydrophobic interactions. As the condensation reaction progresses, the quaternary ammonium salt molecules are gradually encapsulated within the POSS framework, forming a core-shell structure. In this process, the charge complementarity between the quaternary ammonium salt cation and the silicon-oxygen network plays a crucial role: the cation neutralizes the negative charge of the silanol, reducing electrostatic repulsion and promoting the condensation reaction; simultaneously, the steric effect of the quaternary ammonium salt guides the orientation of POSS molecules, optimizing the integrity of the cage structure. The hollowing out of the silicon-based microspheres depends on the selective etching of uncrosslinked silicate regions. Under acidic conditions, the incompletely condensed linear siloxane chains (containing more terminal hydroxyl groups) first undergo hydrolytic breakage, leaving a hollow structure with a highly crosslinked POSS shell. When the microspheres are exposed to seawater, hydroxide ions attack the silicon-oxygen bonds in the shell, causing some cross-linking points to break and expanding the mesoporous channels. Simultaneously, chloride ions in the seawater replace the counterions of the quaternary ammonium salt cations through ion exchange, disrupting the original charge balance and driving the quaternary ammonium salt to diffuse outwards. Initially, highly cross-linked regions only allow small molecular ions to pass through, but as the degree of cross-linking decreases due to hydroxide ion erosion, larger quaternary ammonium salt molecules are released. This allows the microspheres to respond quickly to the high bacterial density at the initial stage of bioattachment while maintaining a long-term antibacterial concentration.

[0024] As a preferred embodiment of the present invention, in S1, the mass ratio of perfluorohexyl ethyl acrylate, silane coupling agent, and azobisisobutyronitrile is (300-330):(75-80):(2-3), for example, it can be (300, 303, 306, 309, 312, 315, 318, 321, 324, 327 or 330):(75.0, 75.5, 76.0, 76.5, 77.0, 77.5, 78.0, 78.5, 79.0, 79.5 or 80.0):(2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 or 3.0), but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0025] In some optional instances, the silane coupling agent is KH560.

[0026] In some alternative instances, the first temperature is 80-90°C, for example, it can be 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0027] In some alternative instances, the reaction time at the first temperature is 6-7 hours, for example, 6.0 hours, 6.1 hours, 6.2 hours, 6.3 hours, 6.4 hours, 6.5 hours, 6.6 hours, 6.7 hours, 6.8 hours, 6.9 hours, or 7.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0028] In some optional examples, the mass ratio of the fluorosilicone prepolymer, hydroxyl-terminated PDMS, dibutyltin dilaurate, and PEEK nanofibers is (700-730):(300-340):(7-10):(50-55), for example, it can be (700, 703, 706, 709, 712, 715, 718, 721, 724, 727, or 730):(300, 304, 308, 312, 316, 320). (324, 328, 332, 336 or 340): (7.0, 7.3, 7.6, 7.9, 8.2, 8.5, 8.8, 9.1, 9.4, 9.7 or 10.0): (50.0, 50.5, 51.0, 51.5, 52.0, 52.5, 53.0, 53.5, 54.0, 54.5 or 55.0), but not limited to the listed values, other unlisted values ​​within this range also apply.

[0029] In some alternative instances, the second temperature is 60-65°C, for example, it can be 60.0°C, 60.5°C, 61.0°C, 61.5°C, 62.0°C, 62.5°C, 63.0°C, 63.5°C, 64.0°C, 64.5°C or 65.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0030] In some optional instances, the stirring time at the second temperature is 30-40 min, for example, 30 min, 31 min, 32 min, 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min or 40 min, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0031] As a preferred embodiment of the present invention, in S2, the mass ratio of tetraethyl orthosilicate, aqueous ethanol solution, aqueous ammonia solution, and PDMS prepolymer is (200-210):(220-230):(4-5):(10-12), for example, it can be (200, 201, 202, 203, 204, 205, 206, 207, 208, 209 or 210):(220, 221, 222, 223, 224, 2... 25, 226, 227, 228, 229 or 230): (4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 or 5.0): (10.0, 10.2, 10.4, 10.6, 10.8, 11.0, 11.2, 11.4, 11.6, 11.8 or 12.0), but not limited to the listed values; other unlisted values ​​within this range also apply.

[0032] In some optional instances, the ethanol-to-water mass ratio in the aqueous ethanol solution is 4:1.

[0033] In some alternative instances, the mass fraction of the ammonia solution is 20-25 wt.%, for example, it can be 20.0 wt.%, 20.5 wt.%, 21.0 wt.%, 21.5 wt.%, 22.0 wt.%, 22.5 wt.%, 23.0 wt.%, 23.5 wt.%, 24.0 wt.%, 24.5 wt.%, or 25.0 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0034] In some optional instances, the hydrolysis time is 24-25 h, for example, 24.0 h, 24.1 h, 24.2 h, 24.3 h, 24.4 h, 24.5 h, 24.6 h, 24.7 h, 24.8 h, 24.9 h, or 25.0 h, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0035] In some optional instances, the PDMS prepolymer is Sylgard184.

[0036] In some alternative instances, the third temperature is 50-55°C, for example, it can be 50.0°C, 50.5°C, 51.0°C, 51.5°C, 52.0°C, 52.5°C, 53.0°C, 53.5°C, 54.0°C, 54.5°C or 55.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0037] In some optional instances, the time for adjusting the temperature to the third temperature and stirring is 12-13 hours, for example, 12.0 hours, 12.1 hours, 12.2 hours, 12.3 hours, 12.4 hours, 12.5 hours, 12.6 hours, 12.7 hours, 12.8 hours, 12.9 hours, or 13.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0038] In some optional examples, the solvent replacement is as follows: first, soaking in ethanol for 4-5 hours, for example, 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, or 5.0h, changing the solution 3 times; then, shaking with ethanol / n-hexane at a volume ratio of 1:1 for 4-5 hours, for example, 4.0h, 4.1h, 4.2h, 4.3h, 4.9h, or 5.0h. The soaking time can be 4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, or 5.0h, with two solution changes. Finally, soak in n-hexane for 4-5h, for example, 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, or 5.0h, with two solution changes. However, this is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0039] In some alternative instances, the mass fraction of the per(xepinus)fluorodecyltriethoxysilane ethanol solution is 5-10 wt.%, for example, it can be 5.0 wt.%, 5.5 wt.%, 6.0 wt.%, 6.5 wt.%, 7.0 wt.%, 7.5 wt.%, 8.0 wt.%, 8.5 wt.%, 9.0 wt.%, 9.5 wt.%, or 10.0 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0040] In some optional instances, the stirring time at the second temperature is 4-5 hours, for example, 4.0 hours, 4.1 hours, 4.2 hours, 4.3 hours, 4.4 hours, 4.5 hours, 4.6 hours, 4.7 hours, 4.8 hours, 4.9 hours, or 5.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0041] As a preferred embodiment of the present invention, in S3, the mass-to-volume ratio of chromium nitrate nonahydrate, terephthalic acid, and DMF aqueous solution is (0.8-1)g:(0.7-0.8)g:40mL. For example, it can be (0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.94, 0.96, 0.98, or 1.00)g:(0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, or 0.80)g:40mL, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] In some optional instances, the fourth temperature is 150-160°C, for example, it can be 150°C, 151°C, 152°C, 153°C, 154°C, 155°C, 156°C, 157°C, 158°C, 159°C or 160°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0043] In some alternative instances, the hydrothermal reaction time is 8-9 hours, for example, 8.0 hours, 8.1 hours, 8.2 hours, 8.3 hours, 8.4 hours, 8.5 hours, 8.6 hours, 8.7 hours, 8.8 hours, 8.9 hours, or 9.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0044] As a preferred embodiment of the present invention, in S4, the mass-to-volume ratio of cyclohexane, Span80, Tween80, and the methyltriethoxysilane / quaternary ammonium salt solution is (85-90) g : (10-12) g : (5-7) g : (40-50) mL, for example, it can be (85.0, 85.5, 86.0, 86.5, 87.0, 87.5, 88.0, 88.5, 89.0, 89.5, or 90.0) g : (10.0, 1 0.2, 10.4, 10.6, 10.8, 11.0, 11.2, 11.4, 11.6, 11.8 or 12.0) g; (5.0, 5.2, 5.4, 5.6, 5.8, 6.0, 6.2, 6.4, 6.6, 6.8 or 7.0) g; (40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50) mL, but not limited to the listed values; other unlisted values ​​within this range also apply.

[0045] In some optional instances, the specified pH is 9.5-10, such as 9.5, 9.6, 9.7, 9.8, 9.9 or 10.0, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0046] In some optional examples, the mass ratio of the methyltriethoxysilane to the quaternary ammonium salt is 5:1.

[0047] In some optional instances, the quaternary ammonium salt is quaternary ammonium salt-15.

[0048] In some optional examples, the solvent for the methyltriethoxysilane / quaternary ammonium salt solution is an aqueous ethanol solution at a volume ratio of 1:1.

[0049] In some alternative examples, the mass fraction of the methyltriethoxysilane / quaternary ammonium salt solution is 20-25 wt.%, for example, it can be 20.0 wt.%, 20.5 wt.%, 21.0 wt.%, 21.5 wt.%, 22.0 wt.%, 22.5 wt.%, 23.0 wt.%, 23.5 wt.%, 24.0 wt.%, 24.5 wt.%, or 25.0 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0050] In some optional instances, the stirring time is 24-25 hours, for example, 24.0 hours, 24.1 hours, 24.2 hours, 24.3 hours, 24.4 hours, 24.5 hours, 24.6 hours, 24.7 hours, 24.8 hours, 24.9 hours, or 25.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0051] In some optional examples, the concentration of the acetic acid solution is 0.1M.

[0052] As a preferred embodiment of the present invention, in S5, the mass-to-volume ratio of the resin matrix, aerogel, ionic liquid composite agent, microsphere agent, and solvent is (500-520)g:(80-90)g:(40-45)g:(30-35)g:(120-130)mL, for example, it can be (500, 502, 504, 506, 508, 510, 512, 514, 516, 518 or 520)g:(80, 81, 82, 83, 84, 8 5, 86, 87, 88, 89 or 90) g; (40.0, 40.5, 41.0, 41.5, 42.0, 42.5, 43.0, 43.5, 44.0, 44.5 or 45.0) g; (30.0, 30.5, 31.0, 31.5, 32.0, 32.5, 33.0, 33.5, 34.0, 34.5 or 35.0) g; 120 mL, but not limited to the listed values, other unlisted values ​​within this range also apply.

[0053] In some optional examples, the solvent is xylene / PMA in a volume ratio of 1:1.

[0054] In a second aspect, the present invention provides an aerogel-reinforced antifouling coating for ships prepared by the preparation method described in the first aspect.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The siloxane segments in the fluorosilicone resin matrix and the silanol groups on the surface of the aerogel form covalent bonds through condensation reaction to achieve molecular-level interface bonding, improve the adhesion between the coating and the substrate, resist the shear stress of water flow, and at the same time, PEEK nanofibers are uniformly dispersed in the resin matrix. Their high specific surface area forms extensive hydrogen bond interaction with the resin, which serves as a stress transfer medium to uniformly distribute the external load to the aerogel skeleton and reduce the damage of local stress to the adhesion.

[0056] (2) The nanopores of the aerogel and the micron-level protrusions of the fluorosilicone resin surface form a rough surface, which reduces the wettability of the sticky substances secreted by marine organisms and inhibits the initial attachment. The MOF mesoporous structure loads ionic liquid, which blocks the formation of biofilm through ion exchange and coordination bond dissociation. The hollow POSS microspheres expand the shell pores in the seawater environment to release quaternary ammonium salts, achieving efficient killing. Detailed Implementation

[0057] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The embodiments described herein are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limiting the implementation of the present invention or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0058] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0059] Example 1

[0060] This embodiment provides an aerogel-reinforced antifouling coating for ships and its preparation method. The preparation method specifically includes the following steps:

[0061] S1, 300g of perfluorohexyl ethyl acrylate, 75g of KH560 and 2.0g of azobisisobutyronitrile were mixed and reacted at 88℃ for 6.3h under a nitrogen atmosphere to obtain a fluorosilicone prepolymer. 700g of the fluorosilicone prepolymer, 300g of hydroxyl-terminated PDMS, 7g of dibutyltin dilaurate and 50g of PEEK nanofibers were mixed and stirred at 60℃ for 30min. After ultrasonic dispersion, a resin matrix was obtained.

[0062] S2, 200g of tetraethyl orthosilicate, 220g of aqueous ethanol solution and 4g of 20wt.% ammonia solution were mixed and hydrolyzed for 24h to obtain SiO2 gel. The SiO2 gel was mixed with 10g of PDMS prepolymer, the temperature was adjusted to 50℃ and stirred for 12h to obtain wet gel. Solvent replacement was then performed to obtain displacement gel. The displacement gel was immersed in 5wt.% per(heptafluorodecyltriethoxysilane aqueous ethanol solution, the temperature was adjusted to 60℃ and stirred for 4h, and vacuum dried to obtain aerogel.

[0063] S3, 0.8g of chromium nitrate nonahydrate and 0.7g of terephthalic acid were dispersed in 40mL of DMF aqueous solution, and the temperature was adjusted to 150℃ for hydrothermal reaction for 8h to obtain product A. Product A was then immersed in 20mL of [BMIM]PF6 methanol solution and vacuum dried to obtain ionic liquid composite additive.

[0064] S4. Mix 85g cyclohexane, 10g Span80 and 5g Tween80, adjust the pH to 9.5 with ammonia, add 40mL of 20wt.% methyltriethoxysilane / quaternary ammonium salt solution and stir for 24h. Then etch with 0.1M acetic acid solution to obtain microsphere additive.

[0065] S5, 500g resin matrix, 80g aerogel, 40g ionic liquid composite additive, 30g microsphere additive and 120mL solvent are mixed to obtain aerogel-reinforced marine antifouling coating.

[0066] Example 2

[0067] This embodiment provides an aerogel-reinforced antifouling coating for ships and its preparation method. The preparation method specifically includes the following steps:

[0068] S1, 330g of perfluorohexyl ethyl acrylate, 80g of KH560 and 3.0g of azobisisobutyronitrile were mixed and reacted at 90℃ for 6.0h under a nitrogen atmosphere to obtain a fluorosilicone prepolymer. 730g of the fluorosilicone prepolymer, 340g of hydroxyl-terminated PDMS, 10g of dibutyltin dilaurate and 55g of PEEK nanofibers were mixed and stirred at 65℃ for 40min. After ultrasonic dispersion, a resin matrix was obtained.

[0069] S2, 210g of tetraethyl orthosilicate, 230g of aqueous ethanol solution and 5g of 25wt.% ammonia solution were mixed and hydrolyzed for 25h to obtain SiO2 gel. The SiO2 gel was mixed with 12g of PDMS prepolymer, the temperature was adjusted to 55℃ and stirred for 13h to obtain wet gel. Solvent replacement was then performed to obtain displacement gel. The displacement gel was immersed in 10wt.% per(heptafluorodecyltriethoxysilane aqueous ethanol solution, the temperature was adjusted to 65℃ and stirred for 5h, and vacuum dried to obtain aerogel.

[0070] S3, 1g of chromium nitrate nonahydrate and 0.8g of terephthalic acid were dispersed in 40mL of DMF aqueous solution, and the temperature was adjusted to 160℃ for hydrothermal reaction for 9h to obtain product A. Product A was then immersed in 20mL of [BMIM]PF6 methanol solution and vacuum dried to obtain ionic liquid composite additive.

[0071] S4. Mix 90g cyclohexane, 12g Span80 and 7g Tween80, adjust the pH to 9.7 with ammonia, add 44mL of 23wt.% methyltriethoxysilane / quaternary ammonium salt solution and stir for 25h, then etch with 0.1M acetic acid solution to obtain microsphere additive.

[0072] S5, 510g resin matrix, 88g aerogel, 44g ionic liquid composite additive, 33g microsphere additive and 120mL solvent are mixed to obtain aerogel-reinforced marine antifouling coating.

[0073] Example 3

[0074] This embodiment provides an aerogel-reinforced antifouling coating for ships and its preparation method. The preparation method specifically includes the following steps:

[0075] S1, 310g of perfluorohexyl ethyl acrylate, 77g of KH560 and 2.6g of azobisisobutyronitrile were mixed and reacted at 80℃ for 7.0h under a nitrogen atmosphere to obtain a fluorosilicone prepolymer. 710g of the fluorosilicone prepolymer, 330g of hydroxyl-terminated PDMS, 9g of dibutyltin dilaurate and 53g of PEEK nanofibers were mixed and stirred at 64℃ for 33min. After ultrasonic dispersion, a resin matrix was obtained.

[0076] S2, 203g of tetraethyl orthosilicate, 225g of aqueous ethanol solution, and 4.3g of aqueous ammonia solution were mixed and hydrolyzed for 24.3h to obtain SiO2 gel. The SiO2 gel was mixed with 11g of PDMS prepolymer, the temperature was adjusted to 54℃ and stirred for 12.7h to obtain wet gel. Solvent replacement was then performed to obtain displacement gel. The displacement gel was immersed in 9wt.% per(heptafluorodecyltriethoxysilane aqueous ethanol solution, the temperature was adjusted to 61℃ and stirred for 4.3h, and vacuum dried to obtain aerogel.

[0077] S3, 0.9g of chromium nitrate nonahydrate and 0.73g of terephthalic acid were dispersed in 40mL of DMF aqueous solution, and the temperature was adjusted to 155℃ for hydrothermal reaction for 8.3h to obtain product A. Product A was then immersed in 20mL of [BMIM]PF6 methanol solution and vacuum dried to obtain ionic liquid composite additive.

[0078] S4. Mix 88g cyclohexane, 10.5g Span80 and 6g Tween80, adjust the pH to 10 with ammonia, add 48mL of 25wt.% methyltriethoxysilane / quaternary ammonium salt solution and stir for 24.6h. Then etch with 0.1M acetic acid solution to obtain microsphere additive.

[0079] S5, 515g resin matrix, 90g aerogel, 45g ionic liquid composite additive, 35g microsphere additive and 120mL solvent are mixed to obtain aerogel-reinforced marine antifouling coating.

[0080] Example 4

[0081] This embodiment provides an aerogel-reinforced antifouling coating for ships and its preparation method. The preparation method specifically includes the following steps:

[0082] S1, 320g of perfluorohexyl ethyl acrylate, 76g of KH560 and 2.3g of azobisisobutyronitrile were mixed and reacted at 83℃ for 6.8h under a nitrogen atmosphere to obtain a fluorosilicone prepolymer. 720g of the fluorosilicone prepolymer, 320g of hydroxyl-terminated PDMS, 8g of dibutyltin dilaurate and 51g of PEEK nanofibers were mixed and stirred at 61℃ for 38min. After ultrasonic dispersion, a resin matrix was obtained.

[0083] S2, 207g of tetraethyl orthosilicate, 228g of aqueous ethanol solution and 4.7g of aqueous ammonia solution were mixed and hydrolyzed for 24.6h to obtain SiO2 gel. The SiO2 gel was mixed with 10.5g of PDMS prepolymer, the temperature was adjusted to 52℃ and stirred for 12.3h to obtain wet gel. Solvent replacement was then performed to obtain displacement gel. The displacement gel was immersed in 7wt.% per(heptadecyl)fluorodecyltriethoxysilane aqueous ethanol solution, the temperature was adjusted to 63℃ and stirred for 4.7h, and vacuum dried to obtain aerogel.

[0084] S3, 0.85g of chromium nitrate nonahydrate and 0.77g of terephthalic acid were dispersed in 40mL of DMF aqueous solution, and the temperature was adjusted to 152℃ for hydrothermal reaction for 8.6h to obtain product A. Product A was then immersed in 20mL of [BMIM]PF6 methanol solution and vacuum dried to obtain ionic liquid composite additive.

[0085] S4. Mix 86g cyclohexane, 11g Span80 and 6.5g Tween80, adjust the pH to 9.6 with ammonia, add 50mL of 21wt.% methyltriethoxysilane / quaternary ammonium salt solution and stir for 24.2h, then etch with 0.1M acetic acid solution to obtain microsphere additive;

[0086] S5, 520g resin matrix, 83g aerogel, 42g ionic liquid composite additive, 31g microsphere additive and 120mL solvent are mixed to obtain aerogel-reinforced marine antifouling coating.

[0087] Comparative Example 1

[0088] This comparative example provides an aerogel-reinforced antifouling coating for ships and its preparation method. The difference between this example and Example 1 is that the mass of the aerogel in S5 is 20g, which is 60g less than that in Example 1. The other method parameters and operating conditions are exactly the same as those in Example 1.

[0089] Comparative Example 2

[0090] This comparative example provides an aerogel-reinforced antifouling coating for ships and its preparation method. The difference between this example and Example 1 is that the mass of the ionic liquid composite additive in S5 is 10g, which is 30g less than that in Example 1. Other method parameters and operating conditions are exactly the same as those in Example 1.

[0091] Comparative Example 3

[0092] This comparative example provides an aerogel-reinforced antifouling coating for ships and its preparation method. The difference between this example and Example 1 is that the mass of the microsphere additive in S5 is 5g, which is 25g less than that in Example 1. Other method parameters and operating conditions are exactly the same as those in Example 1.

[0093] The adhesion test method is GB / T 9286-2021; the impact resistance test method is GB / T 1732-2020; and the biofouling area test method is GB / T 5370-2007. The test results are shown in Table 1.

[0094] Table 1. Test results of aerogel-reinforced marine antifouling coatings in Examples 1-4 and Comparative Examples 1-3.

[0095]

[0096] As shown in Table 1, compared to Example 1, Comparative Example 1 showed decreased adhesion and impact resistance, but increased biofouling area; Comparative Example 2 showed unchanged adhesion, decreased impact resistance, and increased biofouling area; Comparative Example 3 showed unchanged adhesion, decreased impact resistance, and increased biofouling area. Aerogel, as a reinforcing phase, enhances the interfacial bonding between the coating and substrate through chemical bonding with its three-dimensional porous structure. Simultaneously, the nanopores of the aerogel can disperse impact stress. In Comparative Example 1, the reduction in aerogel led to decreased adhesion and impact resistance, while the decrease in surface fluorination modification ratio resulted in an increased biofouling area. In Comparative Example 2, the reduction in ionic liquid composite additives resulted in a certain enhancement of impact resistance from the MOF carrier, thus decreasing impact resistance. Additionally, the insufficient release of imidazole cations increased the biofouling area. In Comparative Example 3, the reduction in microsphere additives resulted in a certain enhancement of impact resistance from the microspheres, thus decreasing impact resistance. The reduction in quaternary ammonium salts loaded on the microspheres also led to an increased biofouling area.

[0097] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. Process for the preparation of aerogel-reinforced antifouling coatings for ships, characterized in that, The preparation method comprises: S1, perfluorohexyl ethyl acrylate, silane coupling agent and azobisisobutyronitrile are mixed to obtain a fluorosilicon prepolymer, the fluorosilicon prepolymer, hydroxyl-terminated PDMS, dibutyltin dilaurate and PEEK nanofiber are mixed to obtain a resin matrix; S2, tetraethyl orthosilicate, ethanol aqueous solution and ammonia solution are mixed and hydrolyzed to obtain a SiO2 gel, the SiO2 gel and PDMS prepolymer are mixed to obtain a wet gel, solvent replacement is performed to obtain a replacement gel, the replacement gel is immersed in a (heptadeca) fluorodecyl triethoxysilane ethanol aqueous solution to obtain an aerogel; S3, chromium nitrate nonahydrate and terephthalic acid are dispersed in a DMF aqueous solution to obtain product A, and then product A is immersed in a [BMIM]PF6 methanol solution to obtain an ionic liquid composite additive; S4, cyclohexane, Span80 and Tween80 are mixed, a methyl triethoxysilane / quaternary ammonium salt solution is added, and an acetic acid solution is used for etching to obtain a microsphere additive; S5, the resin matrix, the aerogel, the ionic liquid composite additive, the microsphere additive and the solvent are mixed to obtain a ship antifouling coating reinforced by the aerogel.

2. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S1: The mass ratio of the perfluorohexyl ethyl acrylate, the silane coupling agent and the azobisisobutyronitrile is (300-330):(75-80):(2-3).

3. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S1: The mass ratio of the fluorosilicon prepolymer, the hydroxyl-terminated PDMS, the dibutyltin dilaurate and the PEEK nanofiber is (700-730):(300-340):(7-10):(50-55).

4. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S2: The mass ratio of the tetraethyl orthosilicate, the ethanol aqueous solution, the ammonia solution and the PDMS prepolymer is (200-210):(220-230):(4-5):(10-12); The PDMS prepolymer is Sylgard 184.

5. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S2: The solvent replacement is as follows: first, ethanol is used for soaking for 4-5h, and the liquid is replaced for 3 times, second, ethanol / n-hexane with a volume ratio of 1:1 is used for oscillation for 4-5h, and the liquid is replaced for 2 times, and finally, n-hexane is used for soaking for 4-5h, and the liquid is replaced for 2 times.

6. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S3: The mass / volume ratio of the chromium nitrate nonahydrate, the terephthalic acid and the DMF aqueous solution is (0.8-1)g:(0.7-0.8)g:40mL.

7. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S4: The mass / volume ratio of the cyclohexane, Span80, Tween80 and the methyl triethoxysilane / quaternary ammonium salt solution is (85-90)g:(10-12)g:(5-7)g:(40-50)mL.

8. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S4: The mass ratio of the methyl triethoxysilane and the quaternary ammonium salt is 5:1; The quaternary ammonium salt is quaternary ammonium salt-15; The concentration of the acetic acid solution is 0.1M.

9. The method of claim 1, wherein the aerogel-reinforced marine antifouling coating is prepared by the steps of: In S5: The mass / volume ratio of the resin matrix, the aerogel, the ionic liquid composite additive, the microsphere additive and the solvent is (500-520)g:(80-90)g:(40-45)g:(30-35)g:(120-130)mL; The solvent is xylene / PMA with a volume ratio of 1:

1.

10. Aerogel reinforced marine antifouling coating obtained by the process according to any one of claims 1 to 9.

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