Method for regulating and controlling closing of nano grooves in fiber surface of snagging-preventing bird eye cloth

Abstract

The invention discloses an anti-snagging bird eye cloth fiber surface nanometer groove closing regulation and control method, and relates to the technical field of textile material surface intelligent regulation and control, and the method comprises the following steps: carrying out stress anchoring pretreatment on a fiber substrate to form a fractal branch crack network and dielectric elastomer composite structure; constructing a humidity response unit, wherein the humidity response unit comprises an ionic liquid gel micro-spring array and a photo-thermal response mesoporous coating; through a cooperation mechanism of low-humidity rigid screening and a high-humidity dynamic valve, closed regulation and control are conducted on the nano groove; according to the invention, a fractal crack double-frequency decoupling mechanism is constructed, a dielectric elastomer is combined to regulate and control a humidity threshold value, an ionic liquid micro-spring quantitatively closes a groove and retains a ventilation channel, and a photo-thermal response coating is cooperated to form double-trigger screening, so that full-scene protection of low-humidity rigid snagging prevention and high-humidity dynamic ventilation is realized; the opposite function limitation of a traditional material is broken through, and the snagging resistance, the breathability and the multifunctional protection capacity of the fabric are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent control of textile material surfaces, and specifically to a method for controlling the closure of nano-grooves on the fiber surfaces of anti-snagging bird's-eye cloth. Background Art

[0002] Anti-snagging bird's-eye fabric, a functional fabric combining lightweight, high breathability, and structural stability, is widely used in sportswear, outdoor equipment, and high-end textiles. Its core performance relies on a mechanism for regulating the closure of nanogrooves on the fiber surface—dynamic closure of the groove structure achieves anti-snagging while maintaining breathability within the fabric's pores. Traditionally, nanogroove closure has been primarily based on the hydrophilic or hydrophobic properties of a single material: hydrophilic materials achieve groove closure through moisture absorption and swelling, while hydrophobic materials rely on surface energy differences to form a physical barrier.

[0003] When natural polymers (such as cellulose and chitosan) or hydrophilic hydrogel materials are used to construct nanogrooves, polar groups such as hydroxyl and carboxyl groups on their molecular chains readily form hydrogen bonds with water molecules in high humidity environments, causing the material to swell. For example, in snag-resistant bird's-eye fabric, swelling can cause deformation of the nanogrooves on the fiber surface, expand the pores, and disrupt the closure mechanism. This not only compromises the snag-proof function but can also increase the risk of snagging due to the increased interfiber spacing. Furthermore, the densification of the material after swelling can block the fabric's breathability, causing the wearer to feel stuffy in high humidity environments, defeating the original purpose of bird's-eye fabric's "high breathability." To circumvent this swelling issue, hydrophobic materials such as polytetrafluoroethylene (PTFE) and silicone rubber are used. While their low surface energy can inhibit water penetration, the clogging of the material's pores by hydrophobic groups and the increased surface tension hinder the diffusion and transmission of gases such as water vapor. For example, the nanogrooves on the surface of hydrophobic fibers can be effectively closed to prevent snagging in a dry environment. However, in a high-humidity environment, due to the lack of a humidity response mechanism, the grooves remain rigidly closed, resulting in a sharp drop in the breathability of the fabric. This cannot meet the needs of human sweat evaporation in sports scenes, seriously affecting wearing comfort and functionality.

[0004] Traditional closure control methods adhere to a single-material design approach, emphasizing either "closed or closed," treating "snagging-resistant" and "breathable and moisture-wicking" as opposing properties. This approach fails to create a synergistic structure that combines humidity responsiveness and graded functionality. A single material cannot achieve controlled closure in high humidity (e.g., uncontrolled swelling of hydrophilic materials) or maintain sustained breathable channels (e.g., rigid closure of hydrophobic materials). This results in bird's-eye fabric facing a technical dilemma of "closure failure and insufficient breathability" in complex environments, severely limiting its application in outdoor environments like heavy rain and high-humidity sports. In outdoor sports and medical protective equipment, high humidity conditions place dual demands on snag-resistant bird's-eye fabric: resistance to rainwater penetration (requiring a stable closure structure) and the ability to quickly dissipate water vapor from human metabolism (requiring high breathability). This inability to balance these two requirements results in outdoor clothing becoming damp on the outside and stuffy on the inside in rainy weather. Medical protective clothing suffers from insufficient breathability, causing discomfort and even skin damage to the wearer. Furthermore, the increased risk of snagging shortens the fabric's lifespan.

[0005] In view of this, a method for regulating the closure of nano-grooves on the fiber surface of anti-snagging bird's eye cloth is provided to overcome the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for regulating the closure of nano-grooves on the fiber surface of anti-snagging bird's eye cloth to solve the problems raised in the above background technology.

[0007] To solve the above technical problems, the present invention provides a method for controlling the closure of nano-grooves on the fiber surface of anti-snagging bird's eye cloth, comprising the following steps: Stress anchoring pretreatment of the fiber substrate forms a composite structure of fractal branching crack network and dielectric elastomer; Constructing a humidity-responsive unit, including an ionic liquid gel microspring array and a photothermal-responsive mesoporous coating; The closure of the nanogrooves is regulated through the synergistic mechanism of low-humidity rigid screening and high-humidity dynamic valves.

[0008] Furthermore, the steps for constructing the fractal branch crack network are: A 355nm wavelength ultraviolet pulse laser is used to spirally scan the surface of PET fiber at a 45° inclination angle to form three-level self-similar branch cracks. The main crack depth is 5-8μm and the pitch is 60μm. The secondary crack depth is 3-5μm, the nano-branch width is 80-120nm and the depth is 200-300nm. 5nmTiO2 nanocrystals are magnetron sputtered on the convex surface of the main crack, and the original hydrophobic groups of PET are retained on the concave surface to form a wettability gradient.

[0009] Furthermore, the steps for constructing the dielectric elastomer composite structure are: Carboxylated CNTs are dispersed in a silicone rubber precursor containing 3-7wt% glycerol. During curing, a 1kV / mm radial pulsed electric field is applied to cause the CNTs to radiate in an umbrella shape along the radial direction of the fiber, with an angle of 75° between the CNTs and the fiber axis.

[0010] Furthermore, the growth steps of the ionic liquid gel microspring array are: Electrochemical deposition was carried out using a triangular wave pulse voltage of -0.5V→0V→-0.5V. EMIM-BF4 ionic liquid was added to the electrolyte to form a right-handed helical structure with a pitch of 100nm. When RH=50%, the pitch was shortened to 85nm.

[0011] Furthermore, the root of the microspring forms a covalent bond with the tip of the microcrack through the hydroxyl group of the TiO2 nanocrystal, and the top extends to the edge of the nanogroove. When the pitch is shortened, the top produces a 15° directional deflection, driving the groove edge to close.

[0012] Furthermore, the modification steps of the photothermal responsive mesoporous coating are as follows: Using CTAB as a structure-directing agent, a mesoporous SiO2 coating loaded with AZO molecules was prepared in an ethanol-water mixed solution with a pH of 10. The AZO molecules were arranged perpendicular to the pores, and the mesopore diameter shrank to 2-3 nm under 365 nm light.

[0013] Furthermore, in the low-humidity rigid screening mode, the width of the nanogroove is smaller than the minimum diameter of the hook body, the microsprings at the edge of the groove are in an extended state to form elastic protrusions, and the CNT network in the dielectric elastomer is partially broken during the hook impact to dissipate energy.

[0014] Furthermore, in the high-humidity dynamic valve mode, the shortening of the microspring pitch and the radial contraction of the dielectric elastomer form a composite drive, causing the groove closure to change nonlinearly with humidity, while retaining the central air permeable channel, whose channel width matches the size of water vapor molecules.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Dual-frequency decoupling of stress response and humidity control solves the functional conflict problem of traditional materials: The three-level self-similar structure of the fractal branching crack network (main crack depth 5-8μm, nanobranch depth 200-300nm) creates a decoupling mechanism of "low-frequency stress dissipation and high-frequency humidity response." The main crack transmits the impact force of wire snags (corresponding to the 1-10Hz frequency of human motion), while the nanobranch responds to humidity changes (matching the 100nm free path of water vapor molecules), thus avoiding the uncontrolled closure of traditional cracks caused by stress confusion. Furthermore, the wettability gradient formed by the TiO2 nanocrystals on the convex surface of the main crack and the hydrophobic groups on the concave surface transforms the crack into a controllable elastic hinge, improving displacement accuracy compared to traditional planar cracks.

[0016] Second, dielectric elastomers synergistically regulate humidity thresholds to achieve a dynamic balance between breathability and closure: In a glycerol-containing dielectric elastomer, the umbrella-shaped CNT network forms a 75° radial arrangement under a 1kV / mm pulsed electric field. Its radial conductivity is several times greater than its axial conductivity, amplifying the radial contraction caused by glycerol's moisture absorption through a lever structure into a driving force for crack tip closure. By adjusting the glycerol content (3-7wt%), the humidity trigger threshold (RH = 35%-65%) can be precisely controlled. For example, 5wt% glycerol corresponds to RH = 50% (suitable for medical protection). This eliminates the need for higher humidity to trigger closure than traditional materials, enabling earlier response in low-humidity environments.

[0017] 3. Ionic liquid gel microsprings are quantitatively closed to improve air permeability and displacement accuracy: A PIL-AAm microspring with a pitch of 100nm, deposited using a -0.5V triangular pulse voltage, shortens to 85nm at RH = 50% due to hydration of EMIM-BF4 ions. This "lever-fulcrum" mechanism drives a 15° deflection of the groove edge, achieving a closure of 76% while retaining a central air permeable channel (width matching the 0.3nm width of a water vapor molecule). This limits swelling to the contraction of the microspring pitch, avoiding the undirectional expansion of traditional hydrogels and improving air permeability compared to hydrophobic materials.

[0018] 4. Dual-trigger screening of photothermal responsive mesoporous coatings to expand multifunctional protection: AZO molecules are directionally loaded on the mesoporous SiO2 coating through CTAB micelles. Under 365nm light, the mesopore diameter shrinks from 3nm to 2nm, forming a synergistic effect with the humidity-driven groove closure: water vapor is allowed to pass through when humidity is dominant, and liquid water and PM2.5 particles are blocked under light. At the same time, the superhydrophobic grooves and the AZO cis structure form a self-cleaning surface, and the fabric's anti-snagging life is extended.

[0019] 5. Collaborative closure mechanism realizes multi-scenario protection: Low-humidity rigid screening: The width of the nano-grooves etched by the femtosecond laser is smaller than the diameter of the snag body. The edge micro-springs stretch to form elastic protrusions. Combined with the dynamic fracture of the CNT network in the dielectric elastomer to dissipate impact energy (the resistance change rate is linearly related to the impact energy), the anti-snagging efficiency is improved and fabric damage can be monitored in real time.

[0020] High-humidity dynamic valve: The shortening of the micro-spring pitch and the radial contraction of the dielectric elastomer are combined to drive the closure degree to change nonlinearly with humidity (for example, the closure degree is 80% when RH=70%). The center of the groove retains a breathable channel to solve the problem of "wet outside and stuffy inside" of traditional materials and improve wearing comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a schematic diagram of the principle of the method for controlling the closure of nano-grooves on the fiber surface of the anti-snagging bird's eye cloth of the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] See also Figure 1 , the present invention provides a technical solution: See Figure 1 As shown, an embodiment of the method for controlling the closure of nano-grooves on the fiber surface of the anti-snagging bird's eye fabric is as follows: 1. "Stress anchoring" pretreatment of fiber substrate: 1. Laser-induced anisotropic microcrack network (helical stress anchor point construction): ① Fractal of self-similar branching network: A 355nm UV pulsed laser (fluence density 3.2J / cm², pulse frequency 15kHz) was used to spirally scan the surface of a PET fiber at a 45° angle. Based on the Wunderlich fractal growth model (fractal dimension D=1.78), a three-level self-similar branching crack was formed along the fiber axis: a primary crack (depth 5-8μm, pitch 60μm) gave rise to secondary cracks (depth 3-5μm, length 20μm) at a 60° angle on either side. Nanoscale branches (width 80-120nm, depth 200-300nm) regenerate at the ends of the secondary cracks. This structure creates a fractal stress concentration effect at the crack tip. Fracture mechanics calculations show that the stress intensity factor at the crack tip is higher than that of a traditional linear crack, and the surface energy distribution exhibits a gradient: the convex surface of the primary crack is magnetron sputtered with 5nm TiO2 nanocrystals, resulting in a hydrophilic and electroactive region; the concave surface retains the original hydrophobic groups of the PET (contact angle 110°), forming a three-level wettability gradient from millimeter to micrometer to nanometer.

[0024] It is necessary to add the following explanations here: The crack image after laser etching is calculated using the box dimension method, and the formula is: ; in: The required side length to cover the crack is The number of squares, the measured crack tip stress intensity factor when D=1.78 2.3 times higher than that of straight crack (based on fracture mechanics formula , the stress concentration coefficient of fractal structure is Y=1.85, and that of traditional structure is Y=0.8).

[0025] The main crack pitch of 60μm corresponds to the characteristic wavelength of wire-snagging impact (the wire-snagging frequency of human body movement is 1-10Hz, corresponding to the stress wavelength of 50-300μm), and the nano-branch depth of 200-300nm matches the diffusion path of water molecules (the free path of water vapor molecules is about 100nm), forming a scale-matched stress-humidity response unit.

[0026] Different from the planar cracks of traditional uniform etching, the fractal branch network has the following characteristics: A. Frequency-selective characteristics of stress conduction: The main crack transmits macroscopic stress (such as snagging impact force), while the nano-branches respond to microscopic humidity-induced deformation, forming a dual-frequency decoupling mechanism of "low-frequency stress dissipation-high-frequency humidity response" (traditional cracks cannot distinguish stresses of different scales); Frequency response model: Main crack natural frequency: (corresponding to low-frequency stress), natural frequency of nano-branch (corresponding to high-frequency stress of humidity changes), achieved through fractal structure Frequency separation ( is the elastic coefficient, for quality).

[0027] B. Directional drive of wettability gradient: The convex hydrophilic area preferentially absorbs moisture and expands, driving the crack opening angle to increase, while the concave hydrophobic area remains rigid, making the entire crack a controllable elastic hinge. Compared with the non-directional swelling of traditional planar cracks, the displacement accuracy is improved.

[0028] ②、Memory elastic fulcrum: By controlling the laser energy density, the crack depth is precisely controlled to penetrate the PET fiber cortex (6μm thick) without damaging the core, forming a "rigid core-elastic cortex" composite structure. TiO2 nanocrystals on the inner wall of the cortical crack form covalent anchors with the subsequently grown ionic liquid gel microsprings through hydroxyl groups, anchoring the microspring's base to the crack tip and extending its tip to the edge of the nanogroove. When the ambient humidity fluctuates, the expansion force generated by moisture absorption in the hydrophilic region of the cortex is amplified by the leverage effect of the crack, driving the microspring's tip to a 15° directional deflection. The rigid support of the core ensures that the fiber's main structure does not deform.

[0029] By limiting the moisture absorption response to the tip of the cortical crack, the core material is prevented from participating in the deformation, achieving "local response-overall stability"; the dynamic adjustment of the crack opening angle allows the nanogrooves to partially close at high humidity while retaining the central breathable channel, which is more rigid and fully closed than traditional hydrophobic materials and has improved air permeability.

[0030] 2. Pre-stretching and fixing of dielectric elastomer (anisotropic braiding of CNT network): ①, Electric field induced umbrella-shaped CNT conductive network: Carboxylated carbon nanotubes (CNTs) (5-10 μm in length and 15 nm in diameter) were dispersed in a silicone rubber precursor containing 5 wt% glycerol (a hydrophilic plasticizer). During curing, a radial pulsed electric field (1 kV / mm, 50 Hz frequency, 100 μs pulse width) was applied. This, leveraging the CNTs' dipole moment orientation (dielectric constant ε = 100), caused them to radiate in an "umbrella-like" pattern along the fiber's radial direction. The CNTs were arranged at a 75° angle to the fiber axis, with their tips pointing toward the fiber surface. This arrangement imparts anisotropic conductivity to the elastomer layer: radial conductivity is several times greater than axial conductivity, creating a composite conductive path characterized by surface stress sensitivity and internal elastic support.

[0031] It is necessary to add the following explanations here: In traditional dielectric elastomers, CNTs are randomly dispersed, making it impossible to achieve directional stress transmission. This method uses a pulsed electric field to form an umbrella-like network of CNTs: Enhanced stress-electrical signal coupling: When the elastomer contracts radially, the dense CNT network on the surface undergoes a change in contact resistance, providing real-time feedback on humidity-induced deformation (traditional methods cannot quantify the closure driving force). Lever amplification of anisotropic shrinkage: Glycerol absorption leads to significant radial shrinkage and weak axial shrinkage. Through the lever structure of umbrella-shaped CNT (the fulcrum is in the fiber core layer), the radial shrinkage displacement is converted into a directional closure driving force at the crack tip, which significantly improves the stress transfer efficiency compared to traditional uniformly dispersed CNTs.

[0032] ② Humidity-responsive gradient shrinkage mechanism: Glycerol molecules in the elastomer layer form hydrogen bonds with water molecules. Moisture absorption increases the distance between the silicone rubber molecular chains, leading to significantly greater radial free volume expansion than axial expansion, resulting in pronounced anisotropic deformation (conventional swelling materials exhibit minimal directional deformation). This directional contraction is directly transmitted to the microcrack tips through the CNT network, where it forms a combined driving force with the shortening of the microspring's pitch, ensuring groove edge closure even at relatively low humidity (conventional materials require higher humidity).

[0033] It is necessary to add the following explanations here: Precise control of the closing threshold: By adjusting the glycerol content, the humidity response threshold can be controlled within a reasonable range to match different application scenarios (such as sportswear, medical protection, and other differentiated humidity triggering requirements); Glycerol content-humidity threshold mapping relationship: Glycerol content 3wt%: trigger humidity RH=65% (suitable for sportswear); Glycerol content 5wt%: trigger humidity RH=50% (suitable for medical protection); Glycerin content 7wt%: Trigger humidity RH=35% (suitable for outdoor rainstorm scenes).

[0034] Dynamic balance of energy dissipation: When the snag impacts the fiber, the umbrella-like structure of the CNT network partially breaks, effectively dissipating the impact energy, preventing the impact force from being transmitted to the microspring, and protecting the humidity-responsive unit from mechanical damage (the closed unit of traditional materials is prone to failure due to impact).

[0035] It is also necessary to explain here that: Providing precise anchoring points for the microspring array: The TiO2 nanocrystals at the crack tip and the PIL-AAm microsprings form a tight chemical anchoring point through intermolecular forces, which minimizes the fixing error at the root of the microspring and ensures precise tip deflection angle when the pitch changes, avoiding the shedding or displacement deviation of traditional uniformly coated microsprings, and providing a stable mechanical fulcrum for the controllable closure of the nanogrooves.

[0036] Laying the foundation for multi-field coupled response: The CNT network in the dielectric elastomer possesses dual functions of stress conduction and environmental sensitivity. It not only transmits mechanical stress but also acts as a humidity-responsive element, providing real-time feedback signals for subsequent intelligent control systems. This multi-field coupling capability extends functionality beyond the capabilities of traditional single, closed structures, laying the foundation for intelligent material upgrades.

[0037] Constructing a bionic hierarchical support skeleton: Fractal branch cracks and umbrella-shaped CNT networks together form a bionic hierarchical support structure, whose stress distribution and deformation characteristics simulate the adaptive mechanism of organisms in nature, achieving the synergy of macrostructure and microscopic response.

[0038] A precisely controllable mechanical-chemical coupling interface was constructed for the subsequent humidity response unit, enabling nanoscale material response to achieve millimeter-level functional output through micron-level structural regulation, forming a multi-dimensional synergistic effect and opening up a new technical path for functional fiber surface treatment.

[0039] 2. Construction of "field effect control" of humidity response unit: 1. Growth of ionic liquid gel microspring arrays (precise control of helical conformation): (1) Pulse waveform of electrochemical deposition: A triangular pulse voltage (-0.5V→0V→-0.5V, 10s cycle) was used instead of conventional direct current deposition to generate a periodically varying electric field strength in the electrolyte. The rising edge of this waveform (0V→-0.5V) aligns the amide groups of the PIL-AAm molecular chains due to the electric field force. During the falling edge (-0.5V→0V), the molecular chains spontaneously coil due to the entropy increase, ultimately forming a right-handed helical structure with a pitch of 100nm. 1-Ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (EMIM-BF4) was added to the electrolyte. Its cations (EMIM+) form strong hydrogen bonds with water molecules (hydration energy ΔH = -25 kJ / mol), while the anions (BF4-) interact with the PIL segments through van der Waals forces. This results in a sudden decrease in the pitch of the microspring at RH = 50% due to ionic hydration, which reduces the spacing between the helical segments.

[0040] It should be noted here that: Quantitative Pitch-Closure Model: Establishing Microspring Pitch and groove closure The relationship: ; When RH=50%, EMIM-BF4 hydration leads to shortened to 85nm, corresponding to , while retaining the width of the central ventilation channel (The diameter of water vapor molecules is 0.3nm, and the diameter of PM2.5 particles is 2500nm, achieving selective screening).

[0041] Under a traditional direct current electric field, polymer chains can only align linearly along the direction of the field and cannot form a helical conformation. This method utilizes the "orientation-relaxation" cycle of a triangular electric field to simulate the self-assembly process of biomacromolecules (such as DNA), converting electrical signals into molecular conformational changes. The addition of EMIM-BF4 does not simply plasticize the material. Instead, through specific ion-water interactions, it converts humidity signals into quantifiable changes in helical pitch, resolving the issues of delayed humidity response and fuzzy thresholds common in traditional hydrogels.

[0042] Limiting swelling to the pitch contraction of the microspring rather than the random volume expansion of traditional materials improves the accuracy of closing displacement; achieving quantitative coupling of humidity changes and structural deformation makes it possible to accurately control humidity in smart clothing.

[0043] (2) “Lever-fulcrum” coupling of microspring: The root of the microspring forms a covalent bond with the microcrack tip through the hydroxyl (-OH) groups of the TiO2 nanocrystals; the tip extends to the edge of the nanogroove, forming a "fulcrum-lever" mechanical system. When the pitch is shortened, the tip deflects in a directional manner, pushing the groove edge toward the center, improving the degree of closure. Simultaneously, the radial contraction of the dielectric elastomer provides additional displacement, further improving the overall degree of closure.

[0044] It is necessary to add the following explanations here: Lever mechanics amplification calculation: microspring length , the distance between the fulcrum and the tip , shortened pitch When the top deflection angle The calculation is as follows: ; Combined with the additional displacement of radial contraction of the dielectric elastomer (5nm), the total deflection angle reaches 15°, corresponding to the groove edge closure displacement .

[0045] Inspired by the mechanosensing mechanism of insect antennae, this approach amplifies molecular-scale swelling into controllable structural-scale displacement through a lever structure. While the volume change of conventional swelling materials cannot be controlled in direction, this method, through a "fixed fulcrum-lever transmission" approach, transforms the undirectional expansion into a directed closure of the groove edge, improving the directionality of displacement. In particular, the response unit (microspring) is confined to the crack tip, creating an island-like structure characterized by "local response and overall stability," avoiding the loss of fiber stiffness associated with traditional uniform coating.

[0046] Therefore, the air permeability is improved compared to traditional hydrophobic materials.

[0047] 2. Photothermal responsive mesoporous coating modification (molecular switch and pore size coordination): (1) "Interlocking" loading of AZO molecules: Using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent, in a 3:1 volume ratio ethanol-water mixture at pH 10, CTAB forms rod-shaped micelles (2 nm in diameter). The hydrophobic ends (azobenzene rings) of the AZO molecules are inserted into the micelle core, while the hydrophilic ends (carboxylic acid groups) are exposed to the aqueous phase. When the SiO2 sol gels, the micelle template is encapsulated to form mesopores. After removal of the CTAB, the AZO molecules are fixed perpendicular to the pores.

[0048] The self-assembly properties of CTAB micelles are exploited to achieve directional alignment of AZO molecules. This "interlocking" loading ensures that the cis- and trans-isomer axes of AZO are perfectly aligned with the mesopore axis, allowing for controllable pore size change. This overcomes the low response efficiency caused by molecular disorder in traditional coatings. Furthermore, combining the light response of AZO with the humidity response of the microspring creates a cross-scale synergy of "molecular switch-nanovalves."

[0049] (2) Coupling of dual-trigger screening mechanism: When humidity dominates closure, the microspring pitch shortens, driving the groove edges to close to a higher ratio. At the same time, the mesopores maintain an appropriate pore size to ensure the free passage of water vapor. If there is light of a specific wavelength (such as strong outdoor light), the AZO molecular isomerization causes the mesopore diameter to further shrink, forming a graded screening effect: Gas screening: water vapor molecules can pass through, while fine particles such as PM2.5 are blocked; Liquid protection: The closed groove edge and the hydrophobic substrate form a super hydrophobic barrier to achieve efficient waterproofing; Snag protection: Snags of varying sizes are blocked by a synergistic combination of groove geometry and elastic capture effects.

[0050] It is necessary to add the following explanations here: Dual trigger timing control: Humidity priority mode: When RH≥50%, the microspring drives the groove to close to 76%, and the mesopore diameter is maintained at 3nm (water vapor passes through); Light priority mode: Under λ=365nm light, the AZO cis isomer shrinks the mesopore diameter to 2nm (blocking water vapor), while the groove closure is locked at 85% (waterproof priority); Synergistic mode: When RH ≥ 50% and light is applied, the mesopore diameter is 2.5nm and the groove closure is 80%, achieving a "waterproof-micro-breathable" balance (attached response timing diagram: humidity trigger delay 10s, light trigger delay 5s).

[0051] Inspired by biological multispectral sensing mechanisms, humidity and light parameters are converted into synergistic responses of materials. By cross-scale matching of mesopore pore size and groove closure, a multi-level screening network from molecular to structural is constructed.

[0052] This achieves multiple functions: snag prevention, waterproofing, breathability, and particle filtration. Under light conditions, the AZO cis-structure and superhydrophobic grooves synergize to form a self-cleaning surface, significantly extending the fabric's service life. Light locks the mesopores, ensuring continued protection even after humidity drops. Snag impact energy is efficiently dissipated through multiple pathways, significantly improving the fabric's fatigue resistance.

[0053] 3. Collaborative Closure Mechanism: 1. Low humidity "rigid screening" mode: (1) Nano-level precision control of geometric screening: Through femtosecond laser etching (wavelength 800nm, scanning speed 5mm / s), the nanogrooves are narrowed to within a range smaller than the minimum diameter of the snag, creating a size-exclusion barrier based on the principle of Brownian motion. Microsprings at the edges of the grooves are stretched, forming elastic protrusions. When a snag contacts the fiber, the protrusions elastically deform, generating a restoring force that counteracts the attractive force between the snag and the fiber, preventing it from embedding.

[0054] It is necessary to add the following explanations here: Inspired by the biofilm sieving mechanism, this fabric transforms the anti-snagging problem into nanoscale dimensional matching, breaking through the traditional hardness anti-snagging approach. The elastic protrusions generate rebound vibration when the snag is detached, achieving self-cleaning, a feature not found in traditional fabrics.

[0055] (2) Dynamic destruction mechanism of conductive network with stress dissipation: The conductive network within the dielectric elastomer partially fractures during a snagging impact, breaking the conductive path and dissipating the mechanical energy through Joule heating. After the impact, the elastomer recovers, reconnecting the network and creating a recyclable dissipation mechanism that responds to high-frequency shocks in real time.

[0056] It is necessary to add the following explanations here: Drawing on the principles of electronic device protection, this technology utilizes the dynamic "destruction-recovery" behavior of a conductive network to dissipate energy, breaking through the limitations of traditional materials that rely on density for dissipation. The change in resistance of the conductive network is linearly correlated with the impact energy, acting as a built-in sensor to monitor fabric damage.

[0057] Linear equation verification: Through the drop hammer impact test (impact energy 0.1-1J), the relationship between the resistance change rate and the impact energy is obtained: ; in: is the initial resistance, unit: , correlation coefficient , which can be used as the calibration basis for damage monitoring sensors.

[0058] 2. High humidity "dynamic valve" mode: (1) Humidity-stress composite driving force of closure: When the ambient humidity rises, the microspring pitch shortens, generating radial displacement. Simultaneously, the dielectric elastomer contracts radially due to moisture absorption, transmitting additional displacement through the conductive network, forming a composite drive that gradually closes the groove. The center of the groove is supported by a fiber core layer, retaining a breathable channel. Its width is graded to match the size of water vapor molecules, ensuring breathability while blocking liquid water.

[0059] It is necessary to add the following explanations here: Inspired by the principles of a bionic siphon, the humidity and stress responses are designed as a tandem drive system, creating a dual-stage response: "threshold triggering and continuous regulation." This solves the problem of excessive swelling in traditional materials while retaining breathable channels and significantly improving air permeability. The relationship between closure and humidity is nonlinear, matching the human sweating threshold and achieving intelligent regulation.

[0060] (2) Molecular dynamics regulation of elastic capture effect: When the pitch of the microspring is shortened, elastic potential energy is stored. When the snagging body triggers displacement, the potential energy is converted into radial elastic force. The force value is greater than the attraction between the snagging body and the fiber but less than the fiber bond energy, ensuring that the microspring will be ejected without damaging the fiber. The ejection process is fast to prevent snagging and entanglement.

[0061] It is necessary to add the following explanations here: Mimicking the jumping mechanism of insects, it converts molecular-scale energy into structural-scale force. Through conformational changes in the microspring, it precisely controls the release of potential energy, exhibiting an "all-or-nothing" response. This solves the problem of snagging damage in traditional materials and significantly reduces the depth of surface damage. The high recovery rate of the microspring's elastic potential energy creates a cyclical protection mechanism, significantly reducing the degradation of the fabric's snagging resistance.

[0062] By confining the humidity-responsive units to a tiny area at the crack tip, the stress concentration effect of the fractal branching crack allows local deflection to drive overall groove closure. This "local-global" driving mechanism is far more efficient than traditional uniform response. Inspired by the triggering mechanism of the Venus flytrap, this approach breaks the conventional wisdom that a higher proportion of responsive units equals better results, achieving energy amplification through fractal structures.

[0063] Summarize: This method addresses the contradiction between the uncontrolled swelling of hydrophilic materials and the insufficient air permeability of hydrophobic materials in traditional anti-snagging bird's-eye cloth. By constructing a fractal branch crack network, dual-frequency decoupling of low-frequency stress and high-frequency humidity response is achieved. A glycerol-containing dielectric elastomer is used to regulate the humidity trigger threshold. Combined with the quantitative closure of ionic liquid gel microsprings, the dual-trigger screening of photothermal responsive mesoporous coatings, and the dynamic energy dissipation mechanism of the conductive network, a multi-field coupled nanogroove closure system is formed. This method accurately balances the "anti-snagging closure" and "graded breathability" functions, achieving a synergistic effect of breathability and anti-snagging in a variety of scenarios, breaking through the technical bottleneck of traditional "either hydrophilic or hydrophobic" material design.

Claims

1. A method for controlling the closure of nano-grooves on the fiber surface of anti-snagging bird's eye cloth, characterized in that: The following steps are involved: Stress anchoring pretreatment of the fiber substrate forms a composite structure of fractal branching crack network and dielectric elastomer; Constructing a humidity-responsive unit, including an ionic liquid gel microspring array and a photothermal-responsive mesoporous coating; The closure of the nanogrooves is regulated through the synergistic mechanism of low-humidity rigid screening and high-humidity dynamic valves.

2. The method for controlling the closure of nano-grooves on the fiber surface of the anti-snagging bird's-eye fabric according to claim 1, characterized in that: The steps for constructing a fractal branching crack network are: A 355nm wavelength ultraviolet pulse laser is used to spirally scan the surface of PET fiber at a 45° inclination angle to form three-level self-similar branch cracks. The main crack depth is 5-8μm and the pitch is 60μm. The secondary crack depth is 3-5μm, the nano-branch width is 80-120nm and the depth is 200-300nm. 5nmTiO2 nanocrystals are magnetron sputtered on the convex surface of the main crack, and the original hydrophobic groups of PET are retained on the concave surface to form a wettability gradient.

3. The method for controlling the closure of nano-grooves on the fiber surface of the snagging-proof bird's-eye fabric according to claim 2, characterized in that: The steps for constructing the dielectric elastomer composite structure are: Carboxylated CNTs are dispersed in a silicone rubber precursor containing 3-7wt% glycerol. During curing, a 1kV / mm radial pulsed electric field is applied to cause the CNTs to radiate in an umbrella shape along the radial direction of the fiber, with an angle of 75° between the CNTs and the fiber axis.

4. The method for controlling the closure of nano-grooves on the fiber surface of snagging-proof bird's-eye fabric according to claim 1, characterized in that: The growth steps of the ionic liquid gel microspring array are: Electrochemical deposition was carried out using a triangular wave pulse voltage of -0.5V→0V→-0.5V. EMIM-BF4 ionic liquid was added to the electrolyte to form a right-handed helical structure with a pitch of 100nm. When RH=50%, the pitch was shortened to 85nm.

5. The method for controlling the closure of nano-grooves on the fiber surface of the snagging-proof bird's-eye fabric according to claim 4, characterized in that: The root of the microspring forms a covalent bond with the tip of the microcrack through the hydroxyl group of TiO2 nanocrystals, and the top extends to the edge of the nanogroove. When the pitch is shortened, the top produces a 15° directional deflection, driving the groove edge to close.

6. The method for controlling the closure of nano-grooves on the fiber surface of the anti-snagging bird's-eye fabric according to claim 1, characterized in that: The modification steps of the photothermal responsive mesoporous coating are as follows: Using CTAB as a structure-directing agent, a mesoporous SiO2 coating loaded with AZO molecules was prepared in an ethanol-water mixed solution with a pH of 10. The AZO molecules were arranged perpendicular to the pores, and the mesopore diameter shrank to 2-3 nm under 365 nm light.

7. The method for controlling the closure of nano-grooves on the fiber surface of the anti-snagging bird's-eye fabric according to claim 1, characterized in that: In the low-humidity rigid screening mode, the width of the nanogroove is smaller than the minimum diameter of the hook body, the microsprings at the edge of the groove are in an extended state to form elastic protrusions, and the CNT network in the dielectric elastomer is locally broken during the hook impact to dissipate energy.

8. The method for controlling the closure of nano-grooves on the fiber surface of snagging-proof bird's-eye fabric according to claim 1, characterized in that: In the high-humidity dynamic valve mode, the shortening of the microspring pitch and the radial contraction of the dielectric elastomer form a composite drive, causing the groove closure to change nonlinearly with humidity, while retaining the central air permeable channel, whose width matches the size of water vapor molecules.

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