Micro-nano hierarchical structure-based super-hydrophilic drainage geotextile and preparation method thereof

Abstract

The application discloses a kind of super-hydrophilic water-absorbing and draining geotextile based on micro-nano hierarchical structure and preparation method thereof, and relates to the field of geotechnical engineering synthetic material and surface modification technology.The super-hydrophilic water-absorbing and draining geotextile provided by the application comprises a geotextile substrate, and then a sandwich composite structure of "interface coupling layer-inorganic nano structure layer-hydrophilic functional layer" is constructed on the surface of the geotextile substrate fibers.The application realizes the stable growth of inorganic nano units on the surface of geotextile fibers through the interface coupling layer, and constructs micron-nano hierarchical roughness;The outer hydrophilic functional layer endows the material with persistent super-hydrophilicity and anti-pollution ability.The above-mentioned geotextile structure utilizes the synergistic effect of the huge capillary suction of nano gap and the macroscopic groove of fiber, improves the air entry value and water conductivity of geotextile, realizes active water absorption and efficient drainage in unsaturated fine-grained soil;The preparation process has strong universality and can be widely applied to roadbed drainage, slope reinforcement and sponge city construction.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering synthetic materials and surface modification technology, and particularly to superhydrophilic and absorbent geotextiles based on micro-nano hierarchical structures and their preparation methods. Background Technology

[0002] Geotextiles, as one of the most widely used synthetic materials in geotechnical engineering, primarily serve four functions: reinforcement, isolation, filtration, and drainage. However, in practical engineering applications such as roadbed drainage, slope reinforcement, and soft soil treatment, traditional geotextiles consistently face a structural contradiction between mechanical strength and drainage capacity. Traditional non-woven geotextiles are typically made from short fibers or filaments through processes such as needle punching and thermal bonding. While their disordered structure endows them with high porosity and good permeability, making them suitable for filtration and drainage applications, the lack of mechanical interlocking results in a low modulus, making them prone to large deformations under stress. This makes them unable to effectively limit lateral displacement of the soil and thus unsuitable for reinforcing roadbeds or enhancing soil stability. In contrast, woven geotextiles, which are orthogonally woven from warp and weft yarns, have advantages such as high modulus, low creep and high strength, making them excellent reinforcing materials. However, their dense structure, despite their vertical permeability, results in extremely low planar water conductivity, making it difficult for water to drain laterally along the fabric plane. This makes it unable to solve the problem of water accumulation and softening inside the roadbed.

[0003] Although nonwoven geotextiles are often used as drainage layers, their drainage efficiency tends to decline significantly over time in complex soil and rock service environments. On one hand, the complex labyrinthine pore structure within the nonwoven fabric easily traps fine soil particles, leading to gradual pore blockage. On the other hand, under the pressure of the overlying soil, the loose fabric thickness is compressed, causing the planar water-conducting channels to narrow or even close, resulting in a loss of drainage capacity. More importantly, the drainage mechanism of traditional geotextiles mainly relies on gravitational potential energy, meaning flow only occurs when the soil reaches saturation. In areas of capillary rise in the subgrade or in unsaturated soil after rainfall, water is trapped between soil particles due to the suction of the soil matrix. Traditional geotextiles cannot actively absorb and drain this water, resulting in "capillary entrapment," which easily leads to subgrade mudslides and other problems.

[0004] In summary, both nonwoven and woven geotextiles have their own irreparable functional defects, which limit their respective application scenarios. Summary of the Invention

[0005] To address the challenges posed by existing geotextiles in unsaturated fine-grained soils, such as capillary barrier effects due to low air permeability leading to unsaturated soil drainage, and the poor bonding strength and aging failure of inorganic nanomaterials on organic fiber surfaces, this invention proposes a superhydrophilic drainage geotextile based on a micro / nano hierarchical structure and its preparation method. This invention retains the high-modulus reinforcement properties of woven geotextiles, utilizing the macroscopic grooves of the irregular cross-section of the geotextile substrate fibers and the special microscopic gaps of the inorganic nanounits to generate a cross-scale synergistic capillary effect. This achieves active water absorption and efficient drainage of unsaturated fine-grained soils, solving the drainage problem. More innovatively, this invention introduces an interface coupling layer and a hydrophilic sealing layer, constructing a unique "sandwich" structure. This effectively solves the durability problem of the inorganic nanostructure layer under soil-rock friction environments, achieving integrated functions of reinforcement, water absorption, drainage, and durability.

[0006] This invention provides a superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure, the structure of which includes a geotextile substrate, an interface coupling layer, an inorganic nanostructure layer, and a hydrophilic sealing layer; the interface coupling layer covers the surface of the geotextile substrate; the inorganic nanostructure layer is composed of an array of inorganic nanounits grown on the surface of the interface coupling layer; the hydrophilic sealing layer covers the surface of the inorganic nanostructure layer and the inner walls of the internal gaps.

[0007] In the aforementioned structure of the superhydrophilic drainage geotextile based on micro-nano hierarchical structure, the geotextile substrate serves as a macroscopic drainage framework; the interface coupling layer is deposited in situ on the fiber surface of the geotextile substrate to provide active sites and enhance interfacial bonding; the inorganic nanounits on the inorganic nanostructure layer form a nanoscale rough surface; and the hydrophilic protective layer penetrates deep into the roots of the inorganic nanounits through solvent replacement and other processes to impart superhydrophilic properties and chemical stability to the material.

[0008] The water migration behavior of absorbent geotextiles follows a dynamic process of "wetting-wicking-evaporation". First, by constructing a superhydrophilic seal layer on the fiber surface, the solid-liquid interface contact angle is reduced, achieving efficient self-absorption of water. Then, by controlling the balance between capillary suction and flow resistance, a high-flux lateral drainage network is constructed. Finally, the matrix suction gradient generated by evaporation provides continuous momentum for the lateral migration of water within the fabric. wicking primarily depends on whether capillary suction can overcome resistance to successfully absorb water and whether there are sufficient lateral drainage channels for lateral drainage.

[0009] In the aforementioned superhydrophilic and absorbent geotextile structure based on micro-nano hierarchical structure, the cross-scale synergistic mechanism of the micro-nano hierarchical structure is as follows: The "nano" level effect (power source) refers to the 100 nm-scale micropores between adjacent inorganic nanounits in the inorganic nanostructure layer. According to the Laplace equation, the extremely small pore radius can generate enormous capillary negative pressure, sufficient to overcome the high matrix suction between unsaturated soil particles, achieving strong capture and self-absorption of micro-pore water in the soil. The "micro" level effect (transmission network) refers to the longitudinal microgrooves (depth and width 0.5-5 μm) formed on the surface of the irregularly shaped fibers and the gaps between fiber filaments (equivalent diameter 10-30 μm). These micron-scale channels construct a low-flow-resistance guiding network, rapidly collecting and distributing the water captured by the nanochannels over long distances laterally.

[0010] Optionally, the fiber material of the geotextile substrate can be polyester (PET), polypropylene (PP) or polyamide (PA), etc., and can generally be filament woven fabric or needle-punched nonwoven fabric.

[0011] Furthermore, the microstructure of the inorganic nanounit is one or more of the following: nanowhisker-like, nanorod-like, nanowire-like, nanosheet-like, and nanoflower-like structures.

[0012] Taking inorganic nanounits in the form of nanocrystal whiskers as an example, their diameter is 50 nm-500 nm and their length is 1 μm-10 μm.

[0013] Furthermore, the constituent materials of the inorganic nanostructure layer include one or more of zinc oxide (ZnO), titanium dioxide (TiO2), silicon dioxide (SiO2), aluminum oxide (Al2O3), and hydroxyapatite (HAp).

[0014] Furthermore, the cross-sectional shapes of the fibers used to prepare the geotextile substrate include, but are not limited to, circular, Y-shaped, cross-shaped, hollow, or multi-lobed shapes. These irregularly shaped structures can provide macroscopic axial water guiding channels.

[0015] Furthermore, the constituent materials of the interface coupling layer include one or more of the following: polydopamine (PDA), polytannic acid (PTA), gallic acid or its metal complex, catechol or its metal complex, silane coupling agents (e.g., γ-aminopropyltriethoxysilane KH550, γ-glycidoxypropyltrimethoxysilane KH560, etc.), tetraethyl orthosilicate (TEOS), polyethyleneimine (PEI), polyacrylic acid (PAA), polyvinyl alcohol (PVA), chitosan, thermal decomposition products of zinc acetate, and thermal decomposition products of zinc nitrate.

[0016] Furthermore, the constituent materials of the hydrophilic protective layer include one or more of the following: polydopamine (PDA), polytannic acid (PTA), polyvinyl alcohol (PVA), chitosan, silane coupling agents (such as γ-aminopropyltriethoxysilane KH550, γ-glycidoxypropyltrimethoxysilane KH560, etc.), and hydrophilic acrylic resin (an acrylic polymer with hydrophilic properties, generally referring to polyacrylic acid with hydrophilic groups attached).

[0017] Optionally, the thickness of the hydrophilic protective layer is 10 nm-50 nm to maintain the connectivity of the nano-gap.

[0018] This invention also provides a method for preparing the above-mentioned superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure, comprising the following steps:

[0019] The interface coupling layer is constructed on the surface of the geotextile substrate using a chemical impregnation method;

[0020] The geotextile substrate coated with the interface coupling layer is placed in a growth solution containing an inorganic precursor, and the inorganic nanostructure layer is formed by growing the interface coupling layer on the surface through a liquid phase synthesis method.

[0021] The geotextile substrate with the inorganic nanostructure layer grown thereon is subjected to hydrophilic sealing treatment to form a hydrophilic sealing layer, thereby obtaining a superhydrophilic absorbent geotextile.

[0022] Before preparing the superhydrophilic and absorbent geotextile, the geotextile substrate needs to be thoroughly cleaned to remove spinning oils, impurities, and dirt from the fiber surface. Optionally, this can be done by sequentially ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water, followed by drying.

[0023] Optionally, the geotextile substrate is immersed in an interfacial coupling solution such as dopamine / Tris buffer to react and form an interfacial coupling layer on the surface of the geotextile fibers.

[0024] Furthermore, the liquid-phase synthesis method is a hydrothermal method, a solvothermal method, a chemical bath deposition method, or a sol-gel method.

[0025] Furthermore, the reaction temperature of the liquid-phase synthesis method is 60-150℃.

[0026] Optionally, the geotextile substrate with the interface coupling layer is immersed in a zinc salt solution to adsorb zinc ions as nucleation sites.

[0027] Optionally, during the hydrophilic sealing treatment, a low-temperature hydrothermal method is used, in which the geotextile substrate is placed in the growth solution of the inorganic precursor and reacted at a predetermined temperature for a period of time (e.g., 3-6 h at 80-95°C) to grow an inorganic nanocrystal array.

[0028] Furthermore, prior to the hydrophilic sealing treatment, the geotextile substrate on which the inorganic nanostructure layer has been grown is pre-wetted.

[0029] Furthermore, the pre-wetting treatment is based on the principle of "solvent replacement". The specific method is as follows: the inorganic nanostructure layer is impregnated and degassed using a low surface tension solvent. Then, before the low surface tension solvent evaporates, it is immediately transferred to an aqueous solution of freshly prepared hydrophilic protective layer material. The miscibility and diffusion of the low surface tension solvent and water are used to guide the molecules of the hydrophilic protective layer material into the nano gaps at the root of the inorganic nanostructure layer and polymerize in situ on the surface of the inorganic nanounits to form a hydrophilic protective layer.

[0030] Optionally, the low surface tension solvent is one or more of ethanol, methanol, acetone, and isopropanol.

[0031] Optionally, after the hydrophilic sealing treatment is completed, low-power ultrasonic cleaning or other methods can be used to remove the surface powder that is physically adsorbed, and then the product can be dried and shaped.

[0032] Compared with the prior art, the advantages of the present invention are:

[0033] 1. The superhydrophilic drainage geotextile provided in this application constructs a stable sandwich structure of "interface coupling layer - inorganic nanostructure layer - hydrophilic sealing layer". It utilizes the huge capillary suction generated by the nano gaps of inorganic nano units to significantly improve the air intake value of the material and can overcome the matrix suction of fine soil to actively absorb water.

[0034] 2. The hydrophilic sealing layer endows the material with long-lasting superhydrophilicity and anti-aging ability. Combined with the macroscopic water-guiding channel of the irregularly shaped geotextile fiber, it realizes the functions of efficient water absorption and drainage and interface reinforcement in unsaturated soil. Attached Figure Description

[0035] Figure 1 This is a schematic cross-sectional view of the microstructure of a single fiber in the superhydrophilic and absorbent geotextile prepared in the example. In the figure, 1 is the geotextile substrate; 2 is the interface coupling layer; 3 is the inorganic nanostructure layer; 4 is the inorganic nanounit; and 5 is the hydrophilic sealing layer.

[0036] Figure 2 This is a schematic diagram of the cross-section of the Y-shaped profiled fiber of the geotextile in the embodiment and the absorption of water onto the fiber surface. In the figure, the gray Y-shaped part is the cross-section of the Y-shaped profiled fiber, and the comb-like structure on the fiber surface represents the interface coupling layer, inorganic nanostructure layer, and hydrophilic sealing layer grown on the surface of the geotextile substrate; the blue part represents the adsorbed water.

[0037] Figure 3This is a schematic diagram of the macroscopic weaving structure and water absorption / drainage flow direction of the superhydrophilic absorbent geotextile prepared in the example. In the diagram, the blue part represents the adsorbed water.

[0038] Figure 4 This is a schematic diagram of the active water absorption mechanism of a water-absorbing geotextile at the soil-fabric interface. In the diagram, water cups located between soil particles are adsorbed onto the nanocrystals on the surface of the geotextile fibers, forming a continuous water film.

[0039] Figure 5 A schematic diagram of the water flow direction for capillary water absorption, lateral drainage, and water evaporation of the geotextile (the dotted part in the figure, which is buried in the roadbed and partially exposed).

[0040] Figure 6 This is a process flow diagram of the preparation of superhydrophilic absorbent geotextile in the example.

[0041] Figure 7 The changes in hydrophilic / hydrophobic properties of the geotextile (with PDA hydrophilic sealing layer) in the embodiment and the comparative example "PDA+ZnO" double-layer geotextile (without hydrophilic sealing layer) in a long-term dark environment are shown. Detailed Implementation

[0042] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] In some embodiments of the present invention, a superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure is provided. The structure includes a geotextile substrate, an interface coupling layer, an inorganic nanostructure layer, and a hydrophilic sealing layer. The interface coupling layer is coated on the surface of the geotextile substrate. The inorganic nanostructure layer is composed of arrayed inorganic nanounits, which are grown on the surface of the interface coupling layer. The hydrophilic sealing layer is coated on the surface of the inorganic nanostructure layer and the inner walls of the internal gaps.

[0044] Optionally, the fiber material used to prepare the geotextile substrate can be polyester (PET), polypropylene (PP) or polyamide (PA), etc., and can generally be filament woven fabric or needle-punched nonwoven fabric.

[0045] Optionally, the microstructure of the inorganic nanounit is one or more of the following: nanowhisker, nanorod, nanowire, nanosheet, and nanoflower structure.

[0046] Optionally, the constituent materials of the inorganic nanostructure layer include one or more of zinc oxide (ZnO), titanium dioxide (TiO2), silicon dioxide (SiO2), aluminum oxide (Al2O3), and hydroxyapatite (HAp).

[0047] Optionally, the cross-sectional shape of the fibers used to prepare the geotextile substrate includes, but is not limited to, circular, Y-shaped, cross-shaped, hollow, or multi-lobed shapes. Using these irregularly shaped structures can provide macroscopic axial water guiding channels.

[0048] Optionally, the constituent materials of the interface coupling layer include one or more of the following: polydopamine (PDA), polytannic acid (PTA), gallic acid or its metal complex, catechol or its metal complex, silane coupling agents (e.g., γ-aminopropyltriethoxysilane KH550, γ-glycidoxypropyltrimethoxysilane KH560, etc.), tetraethyl orthosilicate (TEOS), polyethyleneimine (PEI), polyacrylic acid (PAA), polyvinyl alcohol (PVA), chitosan, thermal decomposition products of zinc acetate, and thermal decomposition products of zinc nitrate.

[0049] Optionally, the hydrophilic protective layer may be composed of one or more of the following: polydopamine (PDA), polytannic acid (PTA), polyvinyl alcohol (PVA), chitosan, silane coupling agents (e.g., γ-aminopropyltriethoxysilane KH550, γ-glycidoxypropyltrimethoxysilane KH560, etc.), and hydrophilic acrylic resin.

[0050] Optionally, the thickness of the hydrophilic protective layer is 10 nm-50 nm to maintain the connectivity of the nano-gap.

[0051] In some embodiments of the present invention, a method for preparing the above-mentioned superhydrophilic and absorbent geotextile based on micro-nano hierarchical structure is also provided, comprising the following steps:

[0052] The interface coupling layer is constructed on the surface of the geotextile substrate using a chemical impregnation method;

[0053] The geotextile substrate coated with the interface coupling layer is placed in a growth solution containing an inorganic precursor, and the inorganic nanostructure layer is formed by growing the interface coupling layer on the surface through a liquid phase synthesis method.

[0054] The geotextile substrate with the inorganic nanostructure layer grown thereon is subjected to hydrophilic sealing treatment to form a hydrophilic sealing layer, thereby obtaining a superhydrophilic absorbent geotextile.

[0055] Before preparing the superhydrophilic and absorbent geotextile, the geotextile substrate needs to be thoroughly cleaned to remove spinning oils, impurities, and dirt from the fiber surface. Optionally, this can be done by sequentially ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water, followed by drying.

[0056] Optionally, the geotextile substrate is immersed in an interfacial coupling solution such as dopamine / Tris buffer to react and form an interfacial coupling layer on the surface of the geotextile fibers.

[0057] Optionally, the liquid-phase synthesis method is a hydrothermal method, a solvothermal method, a chemical bath deposition method, or a sol-gel method.

[0058] Specifically, the reaction temperature of the liquid-phase synthesis method is 60-150℃.

[0059] Optionally, the geotextile substrate with the interface coupling layer is immersed in a zinc salt solution to adsorb zinc ions as nucleation sites.

[0060] Optionally, during the hydrophilic sealing treatment, a low-temperature hydrothermal method is used, in which the geotextile substrate is placed in the growth solution of the inorganic precursor and reacted at a predetermined temperature for a period of time (e.g., 3-6 h at 80-95°C) to grow an inorganic nanocrystal array.

[0061] Optionally, the geotextile substrate on which the inorganic nanostructure layer has been grown is pre-wetted before the hydrophilic sealing treatment.

[0062] The above pre-wetting treatment is based on the principle of "solvent replacement". The specific method is as follows: the inorganic nanostructure layer is wetted and degassed using a low surface tension solvent. Then, before the low surface tension solvent evaporates, it is immediately transferred to an aqueous solution of freshly prepared hydrophilic protective layer material. The miscibility and diffusion of the low surface tension solvent and water are used to guide the molecules of the hydrophilic protective layer material into the nano gaps at the root of the inorganic nanostructure layer and polymerize in situ on the surface of the inorganic nanounits to form a hydrophilic protective layer.

[0063] Optionally, the low surface tension solvent is one or more of ethanol, methanol, acetone, and isopropanol.

[0064] Optionally, after the hydrophilic sealing treatment is completed, low-power ultrasonic cleaning or other methods can be used to remove the surface powder that is physically adsorbed, and then the product can be dried and shaped.

[0065] Example 1

[0066] The superhydrophilic and absorbent geotextile provided in this embodiment is prepared by the following method: Figure 6 As shown, the details are as follows.

[0067] 1. Structure and preparation method of superhydrophilic absorbent geotextile

[0068] The superhydrophilic and absorbent geotextile provided in this embodiment has the following structure: Figure 1As shown, it includes a geotextile substrate 1, an interface coupling layer 2, an inorganic nanostructure layer 3, and a hydrophilic sealing layer 5; the interface coupling layer 2 covers the surface of the geotextile substrate 1; the inorganic nanostructure layer 3 is composed of arrayed inorganic nanounits 4, which are grown on the surface of the interface coupling layer 2; the hydrophilic sealing layer 5 covers the surface of the inorganic nanostructure layer 3 and the inner walls of its internal gaps.

[0069] Specifically, the microstructure of the superhydrophilic absorbent geotextile provided in this embodiment is as follows: Figure 1 and 2 As shown, a "sandwich" structure of "PDA + ZnO + PDA" is formed on the surface of PET geotextile Y-shaped fibers as the base material.

[0070] (1) Substrate pretreatment.

[0071] like Figure 2 As shown, this embodiment uses PET filaments with a Y-shaped fiber cross-section to weave geotextile, and its weaving structure is as follows. Figure 3 The plain weave pattern is shown; the geotextile is then ultrasonically cleaned sequentially in acetone, anhydrous ethanol, and deionized water for 15 minutes each, and dried at 60°C. The geotextile substrate is then cleaned to remove surface impurities.

[0072] (2) Activate the interface and construct the interface coupling layer.

[0073] An interfacial coupling layer was constructed on the fiber surface using a chemical impregnation method, introducing crystal growth nucleation sites. The specific method is as follows:

[0074] Prepare a 2 mg / mL dopamine hydrochloride solution (solvent: 10 mM Tris-HCl buffer, pH=8.5). Immerse the geotextile substrate in the solution and stir at room temperature for 6 h.

[0075] (3) Seed crystals are pre-made and liquid phase growth is used to form inorganic nanounits.

[0076] The treated geotextile was placed in a growth solution containing inorganic precursors, and an inorganic nanostructure layer was grown in situ on the fiber surface via liquid-phase synthesis. The specific method is as follows:

[0077] After the interface is activated, the geotextile is taken out and rinsed with deionized water, then immersed in 0.1 M zinc acetate aqueous solution for 30 min and dried at 80℃.

[0078] A growth solution containing 25 mM zinc nitrate hexahydrate and 25 mM hexamethylenetetramine (HMTA) was prepared. The dried geotextile was vertically suspended in the growth solution and placed in a 95℃ oven for hydrothermal reaction for 4 h.

[0079] After the reaction was completed, the geotextile was removed and thoroughly washed with deionized water to obtain a geotextile with a surface covered with white ZnO nanofibers.

[0080] (4) Hydrophilic modification to construct a hydrophilic protective layer.

[0081] A hydrophilic sealing treatment is applied to geotextiles with inorganic nanostructure layers to form a hydrophilic sealing layer. The specific method is as follows:

[0082] The geotextile covering ZnO nanocrystals was completely immersed in anhydrous ethanol for 20 seconds to displace the air in the nano gaps. After removal, it was kept moist and immediately immersed in a freshly prepared 2 mg / mL dopamine solution (pH 8.5). The mixture was gently shaken and allowed to stand for 1 hour to allow PDA to polymerize in situ on the surface of the ZnO nanocrystals to form an ultrathin hydrophilic film.

[0083] (5) Post-processing. The sample was rinsed alternately with deionized water and ethanol and dried at 60°C to obtain the final superhydrophilic absorbent geotextile.

[0084] 2. The water absorption and drainage principle of superhydrophilic and absorbent geotextiles

[0085] When using superhydrophilic and absorbent geotextiles, the superhydrophilic and absorbent geotextiles are buried under the subgrade soil layer, with a section of geotextile exposed on the subgrade surface. The geotextiles utilize water evaporation to continuously absorb, migrate, evaporate, and release water into the air.

[0086] Specifically, such as Figure 4 and Figure 5 As shown, due to the superhydrophilic protective layer on the fiber surface and the hundreds-nanometer-scale micropores formed between the nanocrystals, the superhydrophilic geotextile exhibits extremely high capillary suction according to the Kelvin equation. This capillary suction effectively overcomes the matrix suction of unsaturated soil, driving pore water into the nanopores within the fabric. The tiny curved surfaces within the nanopores fuse together under surface tension, undergoing capillary condensation and spreading at the whisker roots to form a continuous dynamic water film. Due to the edge angle effect, the converged liquid water rapidly migrates towards the longitudinal microgrooves of the Y-shaped fibers and the pores between the fibers, coalescing into a continuous liquid column. The edge angle effect also significantly reduces the frictional resistance of liquid transport, and combined with the low contact angle environment generated by the superhydrophilic substrate, forms a low-resistance drainage channel. The ends of the geotextile exposed on the roadbed surface generate continuous hydraulic tension through water evaporation, creating a water head pressure difference between the evaporating end and the buried section. This drives water to be transported laterally to the atmosphere along the low flow resistance channels of the irregularly shaped fibers, ultimately achieving "pump-suction" removal of water from the roadbed.

[0087] 3. Microstructure of superhydrophilic and absorbent geotextile

[0088] The inorganic nanounits prepared in this embodiment have a diameter of 50 nm-500 nm and a length of 1 μm-10 μm.

[0089] Microscopic morphology images show that the Y-shaped fiber surface is uniformly covered with upright ZnO nanocrystals, with a diameter of approximately 100 nm and a length of approximately 3 μm, and the PDA layer does not block the gaps between the whiskers. Contact angle testing shows that the water droplet contact angle is 0° (spreading in <0.5 seconds). Vertical wicking tests show that the water absorption height reaches 15 cm within 10 minutes.

[0090] The superhydrophilic and absorbent geotextile provided in this embodiment exhibits a three-peaked soil-water characteristic curve:

[0091] (1) Large pores between yarns (hundreds of micrometers): 1-3 kPa. The weaving process will change the fiber gap and change the specific value of the air intake.

[0092] (2) The gap between individual fibers inside the Y-shaped multifilament and the Y-shaped main groove (micron level): 100-180 kPa, which is related to the size of the fiber itself.

[0093] (3) The gap between nano whiskers on the fiber surface (nanoscale): 2000-2500 kPa, which is related to the whisker morphology, length and spacing.

[0094] Example 2

[0095] The superhydrophilic and absorbent geotextile provided in this embodiment uses polyamide as the base material, and the fiber cross-section is hollow. The interfacial coupling layer is composed of polytannic acid. The inorganic nanostructure layer is constructed using nano-titanium dioxide. The hydrophilic sealing layer also uses polytannic acid.

[0096] Example 3

[0097] The superhydrophilic and absorbent geotextile provided in this embodiment uses polypropylene fiber as the base material, with a cross-shaped fiber cross-section. The interfacial coupling layer is composed of silane coupling agent KH550. The inorganic nanostructure layer is constructed using nano-silica. The hydrophilic sealing layer also uses silane coupling agent KH550.

[0098] Comparative Example 1

[0099] Compared with the structure of the geotextile in Example 1, the structure of the absorbent geotextile provided in this comparative example is different in that the surface of the Y-shaped fibers of the geotextile only forms a double-layer structure of "PDA+ZnO".

[0100] Through experiments, it was found that, Figure 7As shown, when this type of geotextile is buried in the roadbed, the long-term dark environment causes the more thermodynamically stable oxygen atoms to gradually replace the hydroxyl groups, resulting in the inorganic nanostructure layer regaining its hydrophobicity and being unable to achieve water absorption and drainage through capillary action.

[0101] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure, characterized in that, The structure of the superhydrophilic and absorbent geotextile includes a geotextile substrate, an interface coupling layer, an inorganic nanostructure layer, and a hydrophilic sealing layer; the interface coupling layer covers the surface of the geotextile substrate; the inorganic nanostructure layer is composed of arrayed inorganic nanounits, which grow on the surface of the interface coupling layer; the hydrophilic sealing layer covers the surface of the inorganic nanostructure layer and the inner walls of the internal gaps.

2. The superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 1, characterized in that, The inorganic nanounits have a microstructure that is one or more of the following: nanowhiskers, nanorods, nanowires, nanosheets, and nanoflowers.

3. The superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 1, characterized in that, The inorganic nanostructure layer is composed of one or more of zinc oxide, titanium dioxide, silicon dioxide, aluminum oxide, and hydroxyapatite.

4. The superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 1, characterized in that, The cross-sectional shape of the fibers used to prepare the geotextile substrate includes, but is not limited to, circular, Y-shaped, cross-shaped, hollow, or multi-leaf shaped.

5. The superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 1, characterized in that, The constituent materials of the interface coupling layer include one or more of the following: polydopamine, polytannic acid, gallic acid or its metal complex, catechol or its metal complex, silane coupling agent, tetraethyl orthosilicate, polyethyleneimine, polyacrylic acid, polyvinyl alcohol, chitosan, thermal decomposition products of zinc acetate, and thermal decomposition products of zinc nitrate.

6. The superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 1, characterized in that, The hydrophilic protective layer is composed of one or more of the following materials: polydopamine, polytannic acid, polyvinyl alcohol, chitosan, silane coupling agent, and hydrophilic acrylic resin.

7. The method for preparing the superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to any one of claims 1-6, characterized in that, Includes the following steps: The interface coupling layer is constructed on the surface of the geotextile substrate using a chemical impregnation method; The geotextile substrate coated with the interface coupling layer is placed in a growth solution containing an inorganic precursor, and the inorganic nanostructure layer is formed by growing the interface coupling layer on the surface through a liquid phase synthesis method. The geotextile substrate with the inorganic nanostructure layer grown thereon is subjected to hydrophilic sealing treatment to form a hydrophilic sealing layer, thereby obtaining a superhydrophilic absorbent geotextile.

8. The method for preparing a superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 7, characterized in that, The liquid-phase synthesis method is a hydrothermal method, a solvothermal method, a chemical bath deposition method, or a sol-gel method; Furthermore, the reaction temperature of the liquid-phase synthesis method is 60-150℃.

9. The method for preparing a superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 7, characterized in that, Before performing the hydrophilic sealing treatment, the geotextile substrate on which the inorganic nanostructure layer has grown is pre-wetted.

10. The method for preparing a superhydrophilic and absorbent geotextile based on a micro-nano hierarchical structure according to claim 9, characterized in that, The pre-wetting treatment method is as follows: the inorganic nanostructure layer is impregnated and degassed using a low surface tension solvent, and then replaced with a reaction solution containing a hydrophilic protective layer material, so that the hydrophilic protective layer can deeply coat the root of the nanostructure. Furthermore, the low surface tension solvent is one or more of ethanol, methanol, acetone, and isopropanol.

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