A method for preparing a silica composite antireflection coating

Abstract

The present application relates to inorganic optical coating preparation technical field, disclose a kind of preparation method of silica composite antireflection coating, comprising: hollow silica sol and solid silica sol are mixed in anhydrous ethanol and stirred and matched into composite coating fluid, using leaching method is coated on the surface of glass substrate and dry to form porous composite initial film, calcination obtains heat-treated porous composite film, it is placed in airtight reaction cabin and is connected anhydrous ammonia gas and completes gas phase crosslinking, the present application is by adjusting hollow and solid inorganic component distribution ratio to reduce interlayer optical impedance mismatch, utilize the catalytic production of covalent bridging network in particle contact site ammonia molecule in gas phase, strengthen porous skeleton rigidity on the premise of preserving low refractive index optical boundary, improve the durability of composite coating against shear wear and normal impact.

Description

Technical Field

[0001] This invention belongs to the field of inorganic optical coating preparation technology, and particularly relates to a method for preparing a silicon dioxide composite antireflection coating. Background Technology

[0002] Currently, inorganic antireflective coating compositions have value in enhancing the light transmittance of photovoltaic modules. The common practice is to coat and cure a dispersion of spherical nano-silica particles on a glass substrate to construct a thin film with a nanoscale porous stacked network. This structure reduces the refractive index of the film by introducing air, making the film's refractive index match the optical impedance of the substrate, suppressing reflection loss at the interface, and improving visible light transmittance. However, when such coating compositions are used in areas of superimposed stress such as shear stress, particle impact, and alternating damp heat, there is a conflict between optimizing optical response and mechanical durability. To maintain a low refractive index, the film contains a high volume fraction of nanoscale pores. The high porosity directly leads to a reduction in the contact area between nanoparticles. Adjacent particles are only constrained by intermolecular forces or hydrogen bonds. When the coating surface is subjected to stress disturbances caused by sand and dust abrasion or high-pressure water flow, the weakly connected porous framework is prone to irreversible spatial structural displacement or collapse of the porous stacked framework.

[0003] To increase the interparticle bonding stress within the spatial framework, binder materials are typically added to the composition or high-temperature sintering is employed. However, increasing the binder component leads to heterogeneous filling within the porous network, causing blockage of the porous channels by external media. This reduces the air volume fraction within the film, resulting in an increase in the film's refractive index and reflection loss, thus degrading its antireflection performance. High-temperature sintering is limited by the substrate's temperature tolerance, and high thermal stress causes substrate deformation. Furthermore, it is prone to interlayer delamination during alternating heating and cooling due to thermal expansion coefficient mismatch. Besides the limitations of physical coating, existing technologies also have shortcomings in controlling the surface morphology and reaction pathways within the film. For example, Chinese invention patent application CN105776884A discloses a multi-layer... The porous silica antireflective film and its preparation method involve preparing hollow silica spheres using a polymer electrolyte template agent, mixing them with tetraethyl orthosilicate sol for acidic gelation and thermal annealing curing. However, under complex outdoor humid and hot conditions and large mass transfer alternating conditions, there is a fundamental mismatch: it relies on secondary hydrolysis and condensation of liquid precursors. During film drying, the flowing liquid phase binder converges towards the external gaps or pores of the hollow particles, blocking the porous channels, causing the volume density of the closed-pore air cavity to run out of control and the refractive index to increase nonlinearly. Furthermore, it relies on high-temperature annealing at 250℃ to 600℃ to drive the agglomeration of the inorganic framework. In continuous large-size substrate production, surface thermal stress mismatch accumulates. When subjected to wind and sand impacts or continuous shearing and scouring by high-pressure fluids, the interlayer physical stacking cannot provide sufficient shear tension, easily leading to large-area peeling and structural collapse.

[0004] Therefore, the technical problem to be solved by this invention is how to regulate the internal pore network of the nanoporous coating composition to balance the optical refractive index matching requirements, and to construct a continuous and robust chemical covalently bridged system to resist external wear and erosion without changing the solid content of the existing composition. Summary of the Invention

[0005] The present invention aims to solve the problem of the difficulty in achieving both low refractive index optical matching and mechanical durability in nanoporous coating compositions.

[0006] In this technical solution, a method for preparing a silicon dioxide composite antireflective coating includes the following steps:

[0007] Step S101: Hollow silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 40nm to 60nm, dispersed in anhydrous ethanol medium, is mixed with solid silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 15nm to 25nm, dispersed in anhydrous ethanol medium, at a volume ratio of 40:60 to 60:40. The mixture is then homogenized and stirred at a speed of 300rpm to 500rpm for 30min to 60min to obtain a composite silica coating solution.

[0008] Step S102: The composite silica coating solution is coated onto the surface of a washed and dried glass substrate by an immersion method. The immersion method is controlled at a pulling speed of 100 mm / min to 150 mm / min and the relative humidity of the coating environment is 40% to 50%. After coating, the coated glass substrate is placed in an oven at 60°C to 80°C and dried for 10 min to 15 min to obtain a porous composite primary film.

[0009] Step S103: Place the porous composite primary membrane in a muffle furnace and heat it to a calcination temperature of 450°C to 550°C at a heating rate of 5°C / min. Then, calcine it at the calcination temperature for 1 to 2 hours. After calcination, control the muffle furnace and the porous composite primary membrane to cool to room temperature to obtain a heat-treated porous composite membrane.

[0010] In step S104, the heat-treated porous composite membrane is moved into a sealed reaction chamber, and anhydrous ammonia gas is injected into the sealed reaction chamber. The ammonia gas concentration in the sealed reaction chamber is controlled to be 0.05 mol / L to 0.2 mol / L, the pressure in the sealed reaction chamber is maintained at 0.1 MPa to 0.12 MPa, the reaction environment temperature is set to 25℃ to 40℃, and the temperature is maintained for 20 min to 40 min. The injected anhydrous ammonia gas diffuses and penetrates to the particle interface contact sites in the heat-treated porous composite membrane to obtain a silica composite antireflective coating.

[0011] Preferably, in step S101, the preparation step of hollow silica sol includes: mixing anhydrous ethanol with deionized water and ammonia water with a mass percentage concentration of 25%, adding hexadecyltrimethylammonium bromide as a soft template, stirring in a water bath at 30°C to 40°C for 30 min, adding tetraethyl silicate and reacting for 2 h to obtain primary silica with a soft template, centrifuging and washing the primary silica, calcining it at 550°C for 4 h to remove the soft template, and then dispersing it in anhydrous ethanol to obtain hollow silica sol.

[0012] Preferably, step S101 includes the following sub-steps: step S1011, mixing anhydrous ethanol with hollow silica sol and stirring at 200 rpm for 10 min to obtain a first premixed liquid; step S1012, adding solid silica sol to the first premixed liquid, increasing the rotation speed to 400 rpm and homogenizing for 30 min to obtain a composite silica coating liquid.

[0013] Preferably, in step S101, the preparation step of solid silica sol includes: mixing anhydrous ethanol with deionized water and ammonia water with a mass percentage concentration of 25%, stirring at 25°C for 15 min, adding tetraethyl silicate and stirring continuously for 6 h to obtain solid silica sol.

[0014] Preferably, in step S102, the cleaning step of the glass substrate includes: immersing the glass substrate in a 5% sodium hydroxide solution for ultrasonic cleaning for 20 minutes, rinsing with deionized water until the water discharged from the surface is neutral, and finally drying in an oven at 80°C.

[0015] Preferably, in step S102, when using the immersion method to lift the glass substrate, the lifting speed is set to 120 mm / min, and the relative humidity of the coating environment is adjusted to 45%.

[0016] Preferably, in step S102, the coated glass substrate is placed in an oven at 70°C and dried continuously for 12 minutes.

[0017] Preferably, in step S104, anhydrous ammonia gas is continuously introduced into the sealed reaction chamber through the gas valve at the bottom of the sealed chamber, and the total internal pressure in the sealed reaction chamber is adjusted to 0.11 MPa.

[0018] Preferably, after step S104, a film cleaning step is also included: immersing the obtained silica composite antireflective coating in deionized water for 10 minutes, and then drying it with high-pressure pure nitrogen gas to remove the free ammonia molecules remaining on the surface of the silica composite antireflective coating.

[0019] Compared with existing technologies, the method for preparing a silica composite antireflective coating of the present invention has the following advantages:

[0020] 1. In the preparation of silica composite antireflection coating, by adjusting the volume ratio of low-refractive-index hollow silica to dense solid silica, while maintaining the stable morphology of nanoparticles on the surface of the composite coating, the volume fraction of closed-pore air cavities inside the coating exhibits a regular gradient distribution. By utilizing the interlacing of optical equivalent densities of silica with different physical structures, the equivalent refractive index of the composite film is continuously and linearly controlled within the range of 1.18 to 1.27, reducing the impedance mismatch between the coating and the glass substrate. The reflected light generated at the interface of different media between the layers undergoes destructive destructive interference, achieving a high transmittance optical antireflection effect and suppressing reflection loss in the visible light band.

[0021] 2. By employing gas-phase ammonia modification, gas-phase ammonia molecules penetrate into the nanochannels of the porous network. At the contact interface between adjacent silica nanoparticles, free silanol groups on the catalytic surface undergo dehydration condensation, transforming the original physical stacked contact into a dense siloxane covalent bond three-dimensional framework. While maintaining the porous framework from collapsing, the physical thickness of the film is reduced, the boundaries between particles are blurred, and the interlayer fusion adhesion is enhanced. This eliminates the fragile stacking that relies on van der Waals forces and hydrogen bonds, providing a binding force to resist detachment when subjected to severe stress disturbances such as external tangential wear, gravel impact, or water erosion, thus constructing a continuous and robust three-dimensional covalent bridge network.

[0022] 3. Through the synergistic effect of adjusting the ratio of binary composite particles and constructing a covalent network at the gas-phase interface, the dense solid component acts as a support layer for the compressive skeleton, while the closed-cell cavity inside the hollow component maintains the optical boundary of the film with a low refractive index. Furthermore, the cross-linking and locking of the covalent bond network on the surface of adjacent particles enables the composite coating to resist tangential wear and normal impact. Under the harsh application challenges such as heavy load cyclic friction, continuous impact of high-speed sand and gravel, or shearing and scouring by high-flow and high-pressure fluid, the nanoparticles are prevented from physically peeling off from the surface of the glass substrate, thus maintaining the physical structure integrity and optical transmittance stability of the porous network of the composite film over a long period of time. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the preparation process of a silicon dioxide composite antireflection coating according to the present invention;

[0024] Figure 2 This is a system structure diagram of the method for preparing a silicon dioxide composite antireflective coating according to the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0026] A method for preparing a silica composite antireflective coating includes the following steps:

[0027] Step S101: Hollow silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 40nm to 60nm, dispersed in anhydrous ethanol medium, is mixed with solid silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 15nm to 25nm, dispersed in anhydrous ethanol medium, at a volume ratio of 40:60 to 60:40. The mixture is then homogenized and stirred at a speed of 300rpm to 500rpm for 30min to 60min to obtain a composite silica coating solution.

[0028] Step S102: The composite silica coating solution is coated onto the surface of a washed and dried glass substrate by an immersion method. The immersion method is controlled at a pulling speed of 100 mm / min to 150 mm / min and the relative humidity of the coating environment is 40% to 50%. After coating, the coated glass substrate is placed in an oven at 60°C to 80°C and dried for 10 min to 15 min to obtain a porous composite primary film.

[0029] Step S103: Place the porous composite primary membrane in a muffle furnace and heat it to a calcination temperature of 450°C to 550°C at a heating rate of 5°C / min. Then, calcine it at the calcination temperature for 1 to 2 hours. After calcination, control the muffle furnace and the porous composite primary membrane to cool to room temperature to obtain a heat-treated porous composite membrane.

[0030] In step S104, the heat-treated porous composite membrane is moved into a sealed reaction chamber, and anhydrous ammonia gas is injected into the sealed reaction chamber. The ammonia gas concentration in the sealed reaction chamber is controlled to be 0.05 mol / L to 0.2 mol / L, the pressure in the sealed reaction chamber is maintained at 0.1 MPa to 0.12 MPa, the reaction environment temperature is set to 25℃ to 40℃, and the temperature is maintained for 20 min to 40 min. The injected anhydrous ammonia gas diffuses and penetrates to the particle interface contact sites in the heat-treated porous composite membrane to obtain a silica composite antireflective coating.

[0031] Preferably, in step S101, the preparation step of hollow silica sol includes: mixing anhydrous ethanol with deionized water and ammonia water with a mass percentage concentration of 25%, adding hexadecyltrimethylammonium bromide as a soft template, stirring in a water bath at 30°C to 40°C for 30 min, adding tetraethyl silicate and reacting for 2 h to obtain primary silica with a soft template, centrifuging and washing the primary silica, calcining it at 550°C for 4 h to remove the soft template, and then dispersing it in anhydrous ethanol to obtain hollow silica sol.

[0032] Preferably, step S101 includes the following sub-steps: step S1011, mixing anhydrous ethanol with hollow silica sol and stirring at 200 rpm for 10 min to obtain a first premixed liquid; step S1012, adding solid silica sol to the first premixed liquid, increasing the rotation speed to 400 rpm and homogenizing for 30 min to obtain a composite silica coating liquid.

[0033] Preferably, in step S101, the preparation step of solid silica sol includes: mixing anhydrous ethanol with deionized water and ammonia water with a mass percentage concentration of 25%, stirring at 25°C for 15 min, adding tetraethyl silicate and stirring continuously for 6 h to obtain solid silica sol.

[0034] Preferably, in step S102, the cleaning step of the glass substrate includes: immersing the glass substrate in a 5% sodium hydroxide solution for ultrasonic cleaning for 20 minutes, rinsing with deionized water until the water discharged from the surface is neutral, and finally drying in an oven at 80°C.

[0035] Preferably, in step S102, when using the immersion method to lift the glass substrate, the lifting speed is set to 120 mm / min, and the relative humidity of the coating environment is adjusted to 45%.

[0036] Preferably, in step S102, the coated glass substrate is placed in an oven at 70°C and dried continuously for 12 minutes.

[0037] Preferably, in step S104, anhydrous ammonia gas is continuously introduced into the sealed reaction chamber through the gas valve at the bottom of the sealed chamber, and the total internal pressure in the sealed reaction chamber is adjusted to 0.11 MPa.

[0038] Preferably, after step S104, a film cleaning step is also included: immersing the obtained silica composite antireflective coating in deionized water for 10 minutes, and then drying it with high-pressure pure nitrogen gas to remove the free ammonia molecules remaining on the surface of the silica composite antireflective coating.

[0039] Example 1: This example provides a method for preparing a silica composite antireflective coating, suitable for high-transmittance glass substrates in environments with high sand and dust and rainfall, directly subjected to shear wear damage caused by high-speed normal impacts from wind and sand and continuous scouring by high-pressure water. Traditional nanoporous coating compositions, when increasing porosity to approach the target refractive index of 1.23, suffer from insufficient internal chemical bonding strength, leading to large-area collapse and peeling of the particle-packed framework under outdoor normal impacts or mechanical abrasion. If a polymer crosslinking component is introduced to strengthen the framework, the fluid crosslinking agent, under the action of external surface tension, fills the air pores in the particle-packed network, causing a nonlinear increase in the equivalent refractive index, deviating from the range of 1.18 to 1.27. This results in interlayer optical impedance mismatch and increased reflection loss in the glass substrate, making it impossible to meet the low refractive index matching requirement. There is a mutual constraint between the requirements for the formulation and the construction of a high-rigidity and mechanically durable framework. Hollow silica sol with a mass percentage concentration of 2% and an average particle size of 50nm and solid silica sol with a mass percentage concentration of 2% and an average particle size of 20nm are mixed in anhydrous ethanol medium at a volume ratio of 50:50. The speed of the homogenizing stirring system is controlled to be maintained at 400rpm and the homogenization process is continued for 45min to obtain a composite silica coating solution. The composite silica coating solution is coated on the surface of a washed and dried glass substrate using an extraction method. The solvent evaporates and dries to form a porous composite primary film with randomly stacked hollow silica nanoparticles and solid silica nanoparticles. The glass substrate is then transferred to a calcination furnace and calcined at a constant temperature of 450℃ in an air atmosphere for 2h to solidify the porous framework, resulting in a heat-treated porous composite film with a uniformly distributed internal pore network.

[0040] A heat-treated porous composite membrane was placed in a sealed reaction chamber. Anhydrous ammonia gas was introduced into the chamber, and the ammonia concentration was maintained at 70 mg / L. Gaseous ammonia molecules permeated to the interface between hollow and solid silica nanoparticles, catalyzing in-situ dehydration condensation of residual silanol groups on the surfaces of adjacent nanoparticles. This generated a Si-O-Si covalent network at the geometrical interface of the particles, improving the shear strength of the porous framework while maintaining a constant air cavity volume fraction and solid mass. In the actual reaction process, the aforementioned ammonia concentration of 70 mg / L maintained inside the sealed reaction chamber refers to the initial concentration of free gas in the chamber. The transport and maintenance density, in this invention, refers to the local enrichment molar concentration of anhydrous ammonia gas within the nanochannels of the porous composite primary membrane due to capillary condensation and strong chemisorption of surface silanol groups. Due to the micro-confinement effect of the nanopores, gaseous ammonia molecules are largely captured and confined to the local inflection point of particle contact after entering the channels, resulting in an enrichment of the effective reaction concentration in the micro-regions inside the membrane compared to the overall free gas phase density within the chamber. Measurements show that the enriched molar concentration inside the membrane falls precisely within the highly efficient catalytic range of 0.05 mol / L to 0.2 mol / L, thus ensuring the complete progress of the dehydration condensation reaction. This confirms that the ammonia concentration within the sealed reaction chamber is within the optimal range for heat treatment. A local enrichment concentration of 0.05 to 0.2 mol / L was achieved at the particle interface contact sites within the porous composite membrane. Anhydrous ammonia gas was continuously injected into the sealed reaction chamber using a gas-phase mass flow rate control system, maintaining the initial free ammonia density in the gas phase within the sealed reaction chamber at 50 to 90 mg / L. Utilizing the nanoporous confined channels formed by the random stacking of hollow silica sol with an average particle size of 40 to 60 nm and solid silica sol with an average particle size of 15 to 25 nm within the heat-treated porous composite membrane, gaseous ammonia molecules, upon passing through these nanoporous confined channels, experienced capillary aggregation and chemical adsorption by the active silanol groups on the particle surface, resulting in local enrichment at the geometric inflection points of the particle-phase intersections. This was confirmed by offline sample analysis. Weighing and chemical titration analysis calibration showed that an initial free ammonia concentration of 50 to 90 mg / L, maintained at an ambient temperature of 25 to 40°C and a total internal pressure of 0.1 to 0.12 MPa in the sealed reaction chamber, corresponds to a local reaction concentration of 0.05 to 0.2 mol / L at the particle interface contact site. This physical conversion relationship was used as the adjustment parameter for the control valve opening and gas phase input flow rate. After controlling the gas phase crosslinking reaction for 60 minutes, the glass substrate was removed from the sealed reaction chamber. The refractive index of the composite antireflection coating on the surface of the glass substrate was 1.23. The reflected light in the visible light band underwent destructive interference at the interlayer medium interface, and the peak transmittance of the composite antireflection coating was 98%.After undergoing mechanical damage tests involving load friction, high-speed sandblasting normal impact, and continuous high-pressure water jet scouring, the porous framework of the composite antireflective coating maintained its surface structure integrity. The peak transmittance after the mechanical damage tests was greater than or equal to 98%, and the water contact angle on the coating surface changed from the initial 3.39° to 15.54°. A porous inorganic network was established on the glass substrate surface through the complementary physical geometry of hollow and solid silica nanoparticles. A Si-O-Si covalent network was directionally introduced at the particle contact interface using a gas-phase catalytic reaction. This improved the mechanical stiffness of the framework against shear deformation while maintaining the volume density of the closed-pore air cavities within the porous film, thus ensuring that the low refractive index antireflective properties and mechanical durability are maintained simultaneously within the same film structure.

[0041] Example 2: This glass surface treatment experiment was conducted on an automated thin film preparation platform containing a high-precision multi-channel slit extrusion coating unit and a temperature-controlled gas phase reaction chamber. It was used to process a 3.2 mm thick, 300 mm side-length soda-lime glass substrate to simulate the surface anti-reflection protection conditions of an industrial photovoltaic panel. The initial mass percentage concentration of the hollow silica sol in anhydrous ethanol medium was 2%, with an average particle size of 50 nm for the hollow inorganic units. The initial mass percentage concentration of the dense solid silica sol in anhydrous ethanol medium was 2%, with an average particle size of 20 nm for its framework units. The composite silica coating solution was prepared... The homogenization stirring speed is a key parameter for controlling the uniformity of the porous network framework. Its setting aims to reconcile the technical contradiction between component aggregation and segregation caused by low fluid shear force and hollow shell fragmentation caused by high mechanical impact force. A motion judgment model is established based on the force balance relationship between fluid shear rate and nanoparticles in the dispersion medium. When the viscosity of the mixture is 1.2 mPa·s and the Reynolds number of the dispersion medium is in the transition flow range, to ensure that the local shear stress on the hollow shell is less than its critical fracture strength, the homogenization stirring speed is set towards the normal median value within its protected zone. In this experimental group, the stirring speed setting was determined to be 400. The stirring time was set to 45 minutes at rpm to obtain a composite silica coating liquid with uniform element distribution and no structural damage. In actual operation, the aforementioned motion determination model was implemented through the following plain text logic steps: the feed unit was input with a preset mixture viscosity of 1.2 mPa·s and the geometric radius and impeller blade size of the homogenizing tank; the control unit calculated the overall shear rate generated by the fluid at the edge of the impeller blade based on the stirring speed increment from 300 rpm to 500 rpm, and derived the Reynolds number of the dispersion medium by combining the fluid density and characteristic length, determining that it was in the transition range of 2000 to 4000. The flow interval is then determined. Next, the maximum hydrodynamic pressure borne by the hollow silica particles in the transition flow shear field is calculated using a micro-particle shear model and compared with the pre-measured critical fracture strength of the hollow shell, which is 15.0 MPa. When the stirring speed reaches 400 rpm, the calculated local shear stress is 8.4 MPa, which does not exceed the critical fracture strength, and the fluid shear force at this time is sufficient to overcome the van der Waals force aggregation barrier between the hollow and solid particles. Finally, the control unit outputs the judgment result as a safe recommended stirring speed of 400 rpm, thereby achieving process balance within the physical boundary between the overall stirring power and the surface shell strength.

[0042] To confirm the antireflective effectiveness and structural durability of this method, an experimental verification matrix consisting of nine preset process configurations was constructed by adjusting process parameters. Among them, the sample group of this invention, employing the complete process steps with a hollow silica sol to solid silica sol volume ratio of 50:50, an ammonia concentration maintained at 70 mg / L in the gas-phase crosslinking atmosphere, and a reaction duration of 60 min, exhibited a composite antireflective coating with a refractive index of 1.23, a peak transmittance of 98.86% in the visible light range of 380 nm to 780 nm, a surface water contact angle of 15.54°, and a transmittance of 98.35% after undergoing a standard sandblasting abrasion test. The sample group with the volume ratio adjusted to 40:60... The boundary sample group had a refractive index of 1.26, a peak transmittance of 98.12%, a water contact angle of 14.12°, and a transmittance of 97.91% after wear. The upper boundary sample group with a volume ratio adjusted to 60:40 had a refractive index of 1.19, a peak transmittance of 98.92%, a water contact angle of 16.21°, and a transmittance of 97.82% after wear. The lower boundary control group with a volume ratio set to 30:70 had a refractive index that increased to 1.32 and a peak transmittance that decreased to 96.45% due to an excessively high proportion of dense inorganic components leading to insufficient internal closed-cell volume fraction. The transmittance after wear was 96.11%. The control group (70:30) exceeding the upper limit, although its refractive index decreased to 1.15 and its initial peak transmittance reached 99.12%, suffered from insufficient interlayer adhesion due to a lack of solid framework support units. After enduring the same sandblasting impact abrasion, it experienced large-area pulverization and peeling, with the transmittance plummeting to 89.43% after abrasion. The control group (without anhydrous ammonia and a crosslinking concentration of 0 mg / L) exhibited a refractive index of 1.23 and a peak transmittance of 98.85%, but a surface water contact angle of 3.39°. This was due to the absence of a Si-O-Si covalent network at the contact sites of adjacent nanoparticles, leading to particle displacement under frictional shear forces and a decreased transmittance after abrasion. The value decreased to 91.12%; in the second missing feature control group with a volume ratio of 0:100, the porous framework was entirely composed of solid inorganic particles, the film refractive index measurement increased to 1.44, and the initial peak transmittance measurement decreased to 92.15%, indicating impedance matching failure; in the lower limit atmosphere control group with ammonia mass concentration reduced to 40 mg / L, the silanol condensation reaction was incomplete due to insufficient density of gas-phase catalytic active centers, and the transmittance measurement decreased to 94.52% after wear; in the upper limit atmosphere control group with ammonia mass concentration increased to 100 mg / L, the high concentration of alkaline gas induced local irreversible dissolution of the silica framework and clogging of porous channels inside the film, resulting in an abnormal increase in the film refractive index measurement to 1.29. The initial peak transmittance measurement decreased to 97.23%.

[0043] The sample group of the present invention and the control group with the first missing feature were placed together in a sandblasting erosion test chamber to test the performance stability of the film under different erosion times. Quartz sand particles were used as the erosion source, and continuous normal jet damping was set. Under mild erosion conditions with a duration of 5 minutes, the peak transmittance of the sample group of the present invention changed from 98.86% to 98.62%, while the control group with the first missing feature experienced local detachment due to loose accumulation of surface particles under fluid impact, and its transmittance decreased from 98.85% to 93.42%. Under moderate erosion conditions lasting 15 minutes, the porous network of the present invention's sample maintained topological adaptability through covalently stretched resistive lines at the interparticle contact interfaces, and its peak transmittance remained stable at 98.11%. In contrast, the film surface of the control group lacking the first feature underwent shear delamination, and its transmittance further decreased to 87.15%. Under severe erosion conditions lasting 30 minutes, the present invention's sample maintained the continuity of its overall framework structure, and its peak transmittance remained at an enhanced transmittance level of 97.54%, while the control group lacking the first feature... The porous framework underwent overall structural detachment, with its transmittance collapsing to 79.32%. This set of gradient experimental data, showing differentiated evolution with prolonged erosion time, confirms that the Si-O-Si covalent bridging network formed in situ at the particle interface has a mechanical maintenance effect against the dissipation of external mechanical stress. The experimental data indicate that hollow silica nanoparticles and solid silica nanoparticles in a limited volume ratio of 40:60 to 60:40, combined with anhydrous ammonia gas at a mass concentration of 50 mg / L to 90 mg / L, underwent gas-phase catalytic cross-linking. Accordingly, a three-dimensional inorganic network framework with low equivalent refractive index and high shear strength is constructed on the surface of a glass substrate. The specific component ratio and the synergistic operation of the gas-phase catalytic process enable the distribution of closed-pore air cavities inside the porous composite film to reach a preset equilibrium state of optical equivalent density. At the same time, the formation of the mechanical wear-resistant network is limited to the local geometric inflection points where the basic elements contact each other. While maintaining the low refractive index optical matching boundary, the overall interlayer adhesion of the inorganic framework is improved, thus resolving the technical problem in traditional optical coatings where increased porosity and deteriorated mechanical properties are mutually restrictive.

[0044] Example 3: This example combines Figures 1 to 2 The preparation method of a silicon dioxide composite antireflective coating is described, such as... Figure 1As shown, in step S101, hollow silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 40nm to 60nm is mixed with solid silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 15nm to 25nm in anhydrous ethanol at a volume ratio of 40:60 to 60:40, and homogenized at 300rpm to 500rpm for 30min to 60min to obtain a composite silica coating solution. In step S102, the composite silica coating solution is dipped and coated onto the surface of a glass substrate at a pulling speed of 100mm / min to 150mm / min. After coating at a relative humidity of 40% to 50%, the substrate is placed in an oven at 60℃ to 80℃. The membrane is dried for 10 to 15 minutes to obtain a porous composite primary membrane. Then, step S103 is performed, in which the porous composite primary membrane is placed in a muffle furnace and calcined at 450 to 550°C at a rate of 5°C / min for 1 to 2 hours. After cooling to room temperature in the furnace, a heat-treated porous composite membrane is obtained. Finally, in step S104, the heat-treated porous composite membrane is transferred into a sealed reaction chamber, and anhydrous ammonia gas is injected at a concentration of 0.05 mol / L to 0.2 mol / L and a pressure of 0.1 MPa to 0.12 MPa. The temperature is maintained at 25 to 40°C for 20 to 40 minutes to allow the ammonia gas to diffuse and penetrate to the particle interface contact sites for gas-phase cross-linking, thereby obtaining a silica composite antireflection coating.

[0045] like Figure 2 As shown, the constant temperature and humidity coating chamber is equipped with a homogenizing and stirring unit for preparing the composite coating liquid, a feed pump for correcting the process flow rate, and an extraction film forming machine containing a unidirectional vertical electric slide rail to control the flow of the liquid film coating. Downstream from the constant temperature and humidity coating chamber is a drying chamber, which contains a drying execution area for curing the porous composite primary film. Further downstream from the drying chamber is a closed muffle furnace, which is equipped with independent heating components for controlling the heat treatment temperature rise and hold. Downstream from the closed muffle furnace is a sealed reaction chamber, which is equipped with a dual-way air valve circulation system to maintain stable total internal pressure. The system features a pressure control structure and a bottom valve for continuously supplying anhydrous ammonia gas. Downstream of the sealed reaction chamber is a sandblasting erosion test chamber, which includes an environmental stress erosion test module to assess the stability of the thin film structure and performance. In the overall system control architecture, a control unit with dynamic closed-loop correction calculation function and process parameter control core establishes unidirectional control connections with the feed pump, drying oven, closed muffle furnace, and sealed reaction chamber. Meanwhile, a Fourier transform infrared spectrometer is configured on the periphery of the system, and its internal infrared absorption spectroscopy test unit is used to analyze the absorption peak area ratio. Furthermore, a detection correlation path is established between the spectrometer and the sealed reaction chamber.

[0046] Example 4: This glass surface treatment method is applied in a continuous glass panel processing production line environment. The continuously transported ultra-white glass substrate directly bears the shear wind field disturbance and mass transfer stress concentration on the substrate surface caused by the continuous movement of the large-scale production line. This causes local film thickness stress instability in the diluted dispersion during the casting and coating process. Furthermore, in the subsequent continuous gas-phase catalytic crosslinking in the sealed reaction chamber, the large-size glass film has uneven crosslinking from the surface center to the edge due to the nonlinear accumulation of local gas boundary layer diffusion resistance. Traditional surface treatment processes rely solely on fixed empirical curing times. Under non-ideal industrial temperature and humidity fluctuations, insufficient crosslinking leads to deterioration of wear resistance, or excessive crosslinking causes local dissolution and brittleness of the film skeleton. This creates a mutual constraint between meeting the low refractive index matching requirements and constructing a high-rigidity mechanical durability skeleton.

[0047] In a constant temperature and humidity coating chamber with an ambient temperature of 25℃ and a relative humidity of 50%, the dynamic viscosity of the composite silica coating liquid is: Its measured value is 1.2 mPa·s, and the continuous conveying speed of the glass substrate is... Its initial velocity is 0.5 m / s, and the geometric thickness of the porous composite initial membrane is... And its control relationship formula satisfies the following form: ,in, The geometric thickness of the porous composite primary membrane, The dynamic viscosity of the composite silica coating liquid. The continuous transport speed of the glass substrate. This is the fluid property conversion coefficient, which is 3.16 under the current operating conditions; when the conveying speed... When a 10% positive offset occurs, the control unit corrects the process flow rate according to the control relationship formula, adjusting the feed pump to increase the output flow rate of the composite silica coating liquid by 4.8%, thereby increasing the geometric thickness of the porous composite initial film. Maintaining a thickness within the range of 100nm to 150nm, the aforementioned 4.8% increase in the output flow rate of the feed pump controls the geometric thickness as follows: In the casting and extraction zone of the extraction film forming machine, the dynamic balance between the liquid level and the extraction film forming zone determines the meniscus curvature of the fluid boundary layer and the viscous drag force acting on the glass substrate surface. When the conveying speed of the glass substrate deviates by 10% in the positive direction, the volume of liquid carried away from the substrate surface per unit time increases accordingly. If the feed rate remains unchanged, it will cause a momentary drop in the extraction liquid level, thereby changing the shear stress distribution of the fluid boundary layer and causing fluctuations and thinning of the subsequently formed wet film thickness. The control unit sends a control command to the feed pump to increase the output flow rate by 4.8%, ensuring that the fluid volume rate of the replenishment input tank is perfectly matched with the liquid volume rate carried away by the high-speed conveyor, maintaining the liquid level height in the extraction film forming zone within a steady-state error of ±0.1mm, thereby ensuring that the drag thickness of the fluid dynamic boundary layer remains stable within the preset target range. Within the scope, when controlling the geometric thickness of the porous composite primary film using the extraction film forming machine, the control unit corrects the process output flow rate based on pre-stored fluid dynamic boundary layer drag characteristic data when the continuous conveying speed of the glass substrate is positively or negatively offset, causing fluctuations in the wet film thickness. When a 10% positive increase in the continuous conveying speed of the glass substrate compared to the initial speed of 0.5 m / s is detected, the liquid level in the extraction film forming machine area drops instantaneously due to the increase in viscous drag force. The control unit sends a flow compensation command to the feed pump to control the process output flow rate of the feed pump to increase by 4.8% within a preset time constant. By increasing the fluid volume rate replenished to the homogenizing stirring tank, the liquid volume carried away by the increase in continuous conveying speed is offset, so that under the conditions of constant temperature and humidity coating chamber environment temperature of 25℃ and relative humidity of 50%, the meniscus curvature and fluid boundary layer shear stress distribution in the extraction film forming area remain constant, and the final geometric thickness of the porous composite primary film is controlled within the preset target range of 100 to 150 nm.

[0048] In a closed reaction chamber, under a constant gaseous catalytic atmosphere of 70 mg / L anhydrous ammonia, Fourier transform infrared spectroscopy was used to analyze the infrared absorption spectra of multiple sets of experimental glass samples with a time gradient of 10 min and a crosslinking time increasing from 20 min to 80 min. The ratio of the absorption peak area at 960 cm⁻¹ (representing silanol groups) to the absorption peak area at 1080 cm⁻¹ (representing the silicon-oxygen bond network) showed a monotonically decreasing trend with increasing crosslinking time; when the crosslinking time reached 60 min, the decreasing curve of the ratio tended to... The surface is flat and its first derivative converges to 0, indicating that the hydroxyl condensation reaction at the particle interface has reached equilibrium. When the crosslinking time is extended to 80 min, the absorption peak at 1080 cm⁻¹ undergoes a redshift and splits, and the porous framework undergoes local dissolution. Therefore, 60 min is determined to be the processing time for anhydrous ammonia gas-phase crosslinking. In actual industrial production, the aforementioned fixed time of 60 min determined by the experimental glass sample is stored in the control unit as the benchmark initial prediction value in the system control architecture, while the infrared absorption spectroscopy testing unit of the aforementioned Fourier transform infrared spectrometer is located in a sealed reaction chamber. During operation, the surface chemical state of the large-size glass film is scanned in real time via a reflective in-situ optical window. The control unit extracts the ratio of the absorption peak areas of 960 cm⁻¹ and 1080 cm⁻¹ measured in situ and compares it online with the convergence trend of the first derivative of the baseline historical curve. When the rate of decrease of this ratio is detected to be less than 0.001 for three consecutive acquisition cycles and tends to flatten, the control unit determines that the particle contact interface of the current batch of film has reached the reaction equilibrium endpoint, and dynamically issues a command to close the bottom gas valve and open the... The control command for activating the dual-channel gas valve circulation pressure control structure to remove residual ammonia effectively combines offline calibration baseline with online in-situ monitoring, achieving dynamic closed-loop correction of process time under non-ideal production conditions. During gas-phase crosslinking in the sealed reaction chamber, the infrared absorption spectroscopy testing unit inside the Fourier transform infrared spectrometer scans the moving silica composite antireflection coating surface online through a reflective in-situ optical window, collecting infrared absorption spectral data of the thin film surface and transmitting it as an input signal to the control unit. The control unit extracts and calculates the 960 cm⁻¹ value representing the stretching vibration characteristics of the surface-active silanol groups. -1 The absorption peak area at this point is similar to that at 1080 cm⁻¹, which represents the asymmetric stretching vibration characteristic of silicon-oxygen bonds. -1 The absorption peak area at 960 cm⁻¹ -1 The absorption peak area at 1080 cm⁻¹ -1The ratio of the absorption peak area is used to determine the real-time area ratio. The control unit determines that when the real-time area ratio is 0.12 for three consecutive acquisition cycles and the absolute value of the rate of change with crosslinking time is less than 0.001, this state is confirmed as the equilibrium endpoint of the hydroxyl condensation reaction at the particle contact interface. A control command is issued to close the gas valve at the bottom of the sealed chamber, open the dual-way gas valve circulation control structure to remove the residual anhydrous ammonia in the chamber, and terminate the gas phase catalytic reaction to prevent local dissolution of the porous silica framework. The film on the surface of the high-transmittance glass substrate has an equivalent refractive index of 1.23 in the visible light band of 380nm to 780nm, and its peak transmittance is 98.86%. After undergoing a damp heat cycling aging test, the film exhibits destructive destructive interference of reflected light. Its peak transmittance after the shear failure test is greater than or equal to 98%, and the surface water contact angle of the film is 15.54°. The inorganic optical coating establishes a porous network through the stacking of hollow silica nanoparticles and solid silica nanoparticles, utilizing geometric thickness. With conveying speed The control relationship is adjusted to adjust the liquid film coating flow, and the gas-phase ammonia catalytic molecules are used to form a Si-O-Si covalent network at the local inflection point of the nanoparticle contact. While maintaining the air cavity volume density inside the porous film, the mechanical strength of the skeleton against shear deformation is enhanced, so that the low refractive index characteristics and mechanical durability are maintained together in the same film structure.

[0049] Example 5: When the system faces the condition that the residual moisture in different batches of hollow silica sol fluctuates, causing the initial hydroxyl density of the porous composite primary film to deviate from the baseline, the reaction sites on the skeleton surface jump, causing the subsequent anhydrous ammonia catalytic curing path to shift. In the pre-stage process, a property normalization method for the reaction environment is introduced to stabilize the curing network. The initial state definition procedure stipulates that the glass substrate with the porous composite primary film is sent into the sealed reaction chamber, the internal pressure is reduced to 0.01MPa by evacuation, and the temperature is kept constant at 120°C for 30 minutes to remove the free water molecules adsorbed in the capillary channels of the primary film. The hydroxyl density on the surface of the primary film is adjusted to converge to the preset adsorption baseline, and the pre-curing baseline is established without changing the topological stacking morphology of the nanoparticles.

[0050] After the pre-dehydration process is completed, high-purity nitrogen is introduced into the sealed reaction chamber to restore the pressure to 0.1 MPa. The temperature inside the chamber is then adjusted to cool and stabilize at 25°C. Anhydrous ammonia is introduced and its concentration is maintained at 70 mg / L. Gaseous ammonia molecules permeate along porous channels to the interface between nanoparticles, directionally inducing condensation reactions of hydroxyl groups between adjacent units. An in-situ Si-O-Si inorganic bridging covalent network is constructed at the particle contact inflection point. The refractive index of the treated composite antireflective coating is stable at 1.23, the peak transmittance in the visible light band (380 nm to 780 nm) remains at 98.86%, the surface water contact angle is stable at 15.54°, and it exhibits mechanical durability after being subjected to sandblasting abrasion.

[0051] Example 6: When the system faces fluctuations in relative humidity and variations in batch material parameters, the optical impedance matching boundary and physical stacking stiffness of the porous composite film are adaptively adjusted through a standardized engineering calibration procedure. The production equipment used for this glass surface treatment method includes an extraction film-forming machine equipped with a unidirectional vertical electric slide rail. The lifting speed error of the electric slide rail is less than or equal to 0.5 mm / min. It is equipped with a closed muffle furnace with temperature control accuracy better than ±1℃ and independent heating components for each zone, as well as a sealed reaction chamber with a dual-channel gas valve circulation pressure control structure. In actual engineering practice, the aforementioned fluid property conversion coefficient of 3.16 was determined through fluid dynamic calibration experiments on the surface tension of anhydrous ethanol medium at 25℃ (22.3 mN / m), dynamic viscosity (1.2 mPa·s), and surface tension of the glass substrate. A constant coefficient is defined. When this coefficient is below 2.80, it means insufficient fluid wettability, resulting in a lower theoretical thickness calculated by the system, which will lead to defects such as broken lines and missed coatings in the actual coating. When it is above 3.50, it will cause the wet film thickness to exceed the standard and cause subsequent drying cracking. The aforementioned constant coefficient of 0.48 is the transmission gain obtained by interactive calibration of the rated head-flow curve of the feed pump and the liquid level response damping of the extraction film forming machine. Its physical lower limit is 0.40. Below this value, the flow compensation will have a time lag and will not be able to offset the speed disturbance in time. Its physical upper limit is 0.55. Above this value, the feed pump will overshoot, which will cause liquid surface fluctuations and streaks. The values ​​of both ensure the precise adaptive adjustment of the control loop within the critical stability boundary. The control unit calculates the percentage increase in the process output flow of the composite silica coating liquid according to the formula. ,in, The percentage increase in process output flow rate correction. This is a constant coefficient, which takes a value of 0.48 under the current operating conditions; The percentage change in lifting speed is given. Under this process parameter control, when the lifting speed deviates positively by 10%, the process output flow rate increases by 4.8% to offset the decrease in liquid film thickness caused by the increased lifting speed. This maintains the geometric thickness of the porous composite primary film within the range of 100nm to 150nm. The aforementioned decrease in liquid film thickness due to increased lifting speed refers to the sharp increase in the shear rate of the fluid element surface caused by the positive deviation of the lifting speed under continuous processing and overall airflow disturbance. This leads to a nonlinear acceleration of the local evaporation rate of the solvent on the liquid film surface, resulting in overall volume shrinkage of the wet film due to excessive solvent evaporation. This shrinkage and thinning effect exceeds the theoretical thickening effect brought about by fluid viscous drag. By increasing the flow rate, a supplementary boundary layer is constructed on the micro-area liquid surface of the extraction film forming machine using the increased process output flow rate to compensate for the liquid phase volume lost due to shear evaporation. This keeps the geometric thickness of the porous composite primary film within the preset target range, ensuring that the final geometric thickness of the porous composite primary film is stable within the range of 100nm to 150nm.

[0052] The preparation procedure for the first verification group consists of the following steps: A hollow silica sol with a mass percentage concentration of 1% and an average particle size of 40 nm is mixed with a solid silica sol with a mass percentage concentration of 1% and an average particle size of 15 nm in anhydrous ethanol medium, and the volume ratio of the two is adjusted to 40:60; homogenization is performed for 60 min at 300 rpm using a homogenizing stirring unit to prepare the first composite silica coating solution; a clean glass substrate is immersed in and lifted out of the first composite silica coating solution using a slide rail at a speed of 100 mm / min, while maintaining the relative humidity of the film-forming chamber at 40%; the glass substrate is transferred to a drying oven at 60°C and dried for 15 min to obtain the first porous composite initial film; the first porous composite initial film is placed in a closed muffle furnace and dried at 5°C / m... The temperature was raised to 450℃ at a heating rate of in and calcined at a constant temperature for 2 hours. The mixture was then cooled to room temperature in the furnace to obtain a first heat-treated porous composite membrane. The first heat-treated porous composite membrane was transferred into a sealed reaction chamber, and anhydrous ammonia gas was injected into the sealed reaction chamber and the ammonia concentration was adjusted to be stable at 0.05 mol / L. The total internal pressure in the sealed reaction chamber was maintained at 0.1 MPa, and the reaction environment temperature was set at 25℃ and maintained at a constant temperature for 20 minutes. Gaseous ammonia molecules diffused and penetrated into the particle interface contact sites in the first heat-treated porous composite membrane, catalyzing the dehydration and condensation of free silanol groups on the surface, forming a three-dimensional siloxane network at the geometric interface of the particle contact. The obtained sample was immersed in deionized water for 10 minutes, and the remaining free ammonia molecules on the membrane surface were dried using high-pressure pure nitrogen gas, resulting in a first silica composite antireflective coating sample on the glass substrate.

[0053] The preparation procedure for the second verification group consists of the following steps: A hollow silica sol with a mass percentage concentration of 2% and an average particle size of 50 nm is mixed with a solid silica sol with a mass percentage concentration of 2% and an average particle size of 20 nm in anhydrous ethanol medium, and the volume ratio of the two is adjusted to 50:50; homogenization is performed for 45 min at 400 rpm using a homogenizing stirring unit to prepare the second composite silica coating solution; a clean glass substrate is immersed in and lifted out of the second composite silica coating solution using a slide rail at a speed of 125 mm / min, while maintaining the relative humidity of the film-forming chamber at 45%; the glass substrate is transferred to a drying oven at 70°C and dried for 12 min to obtain the second porous composite initial film; the second porous composite initial film is placed in a closed muffle furnace and heated at 5°C / min. The temperature was increased to 500℃ and calcined at a constant temperature for 1.5 hours, then cooled to room temperature in the furnace to obtain a second heat-treated porous composite membrane. The second heat-treated porous composite membrane was transferred into a sealed reaction chamber, and anhydrous ammonia gas was injected into the sealed reaction chamber and the ammonia concentration was adjusted to be stable at 0.125 mol / L. The total internal pressure in the sealed reaction chamber was maintained at 0.11 MPa, and the reaction environment temperature was set at 32.5℃ and maintained at a constant temperature for 30 minutes. The gaseous ammonia molecules diffused and penetrated into the particle interface contact sites in the second heat-treated porous composite membrane, catalyzing the dehydration and condensation of free silanol groups on the surface, forming a three-dimensional siloxane network at the geometric interface of the particle contact. The obtained sample was immersed in deionized water for 10 minutes, and the remaining free ammonia molecules on the membrane surface were dried using high-pressure pure nitrogen gas, resulting in a second silica composite antireflective coating sample on the glass substrate.

[0054] The preparation procedure for the third verification group consists of the following steps: A hollow silica sol with a mass percentage concentration of 3% and an average particle size of 60 nm is mixed with a solid silica sol with a mass percentage concentration of 3% and an average particle size of 25 nm in anhydrous ethanol medium, and the volume ratio of the two is adjusted to 60:40; homogenization is performed for 30 minutes at 500 rpm using a homogenizing stirring unit to prepare the third composite silica coating solution; a clean glass substrate is immersed in and lifted out of the third composite silica coating solution using a sliding rail at a speed of 150 mm / min, while maintaining the relative humidity of the film-forming chamber at 50%; the glass substrate is transferred to an 80°C drying oven and dried for 10 minutes to obtain the third porous composite initial film; the third porous composite initial film is placed in a closed muffle furnace and heated at 5°C / m... The temperature was increased to 550℃ at a heating rate of in and calcined at a constant temperature for 1 hour. The mixture was then cooled to room temperature in the furnace to obtain a third heat-treated porous composite membrane. The third heat-treated porous composite membrane was transferred into a sealed reaction chamber, and anhydrous ammonia gas was injected into the chamber and the ammonia concentration was adjusted to be stable at 0.2 mol / L. The total internal pressure in the sealed reaction chamber was maintained at 0.12 MPa, and the reaction environment temperature was set at 40℃ and maintained at a constant temperature for 40 minutes. The gaseous ammonia molecules diffused and penetrated into the particle interface contact sites in the third heat-treated porous composite membrane, catalyzing the dehydration and condensation of free silanol groups on the surface, forming a three-dimensional siloxane network at the geometric interface of the particle contact. The obtained sample was immersed in deionized water for 10 minutes, and the remaining free ammonia molecules on the membrane surface were dried using high-pressure pure nitrogen gas, resulting in a third silica composite antireflective coating sample on the glass substrate.

[0055] The fourth verification group, serving as a control group lacking hollow silica inorganic elements, consisted of the following steps: 1) Adding solid silica sol with a mass percentage concentration of 2% and an average particle size of 20 nm to anhydrous ethanol medium; 2) Homogenizing the solution for 45 min at 400 rpm using a homogenizing stirring unit to prepare the fourth silica coating solution; 3) Immersing and pulling a clean glass substrate in the fourth silica coating solution at a speed of 125 mm / min using a sliding rail, maintaining the relative humidity of the film-forming chamber at 45%; 4) Drying the glass substrate in a 70°C drying oven for 12 min to obtain the fourth porous composite primary film; 5) Placing the fourth porous composite primary film... The sample was placed in a closed muffle furnace and heated to 500℃ at a heating rate of 5℃ / min and calcined at a constant temperature for 1.5h. It was then cooled to room temperature with the furnace to obtain the fourth heat-treated porous composite membrane. The fourth heat-treated porous composite membrane was transferred into a sealed reaction chamber, and anhydrous ammonia gas was injected into the sealed reaction chamber and the ammonia concentration was adjusted to be stable at 0.125mol / L. The total internal pressure in the sealed reaction chamber was maintained at 0.11MPa, and the reaction environment temperature was set at 32.5℃ and maintained at a constant temperature for 30min. The obtained sample was immersed in deionized water for 10min, and the free ammonia molecules remaining on the film surface were dried using high-pressure pure nitrogen gas to obtain the fourth silicon dioxide composite antireflection coating sample on the glass substrate.

[0056] The fifth verification group, serving as a control group lacking the gas-phase ammonia crosslinking reaction, consisted of the following steps in its preparation procedure: the fifth heat-treated porous composite membrane was prepared according to the same material specifications and process parameters as the second verification group, omitting the anhydrous ammonia injection and gas-phase crosslinking reaction process, and the fifth heat-treated porous composite membrane was directly removed from the sealed reaction chamber to obtain the fifth silica composite antireflection coating sample on the surface of the glass substrate.

[0057] Based on the spectroscopic brightness characteristics and wear durability test results of the samples in the above verification groups, reproducible test data were obtained: The first silica composite antireflective coating sample has an equivalent refractive index of 1.26, an initial peak transmittance of 98.20% at a wavelength of 590nm, and after being subjected to 80 cycles of continuous cyclic rubbing with an anhydrous ethanol cotton ball under a 500g load, the peak transmittance of the first silica composite antireflective coating sample remained at 97.80%, and the surface static water contact angle remained at 14.20°; the second silica composite antireflective coating sample has an equivalent refractive index of 1.23, an initial peak transmittance of 98.86% at a wavelength of 557nm, and after being subjected to 80 cycles of continuous cyclic rubbing with anhydrous ethanol cotton ball under a 500g load, the peak transmittance of the first silica composite antireflective coating sample remained at 97.80%, and the surface static water contact angle remained at 14.20°; After 80 cycles of cyclic rubbing under the same friction conditions, the peak transmittance of the second silica composite antireflective coating sample remained at 98.06%, and the static water contact angle remained at 15.54°. The third silica composite antireflective coating sample had an equivalent refractive index of 1.19 and an initial peak transmittance of 98.35% at a wavelength of 510 nm. After 80 cycles of cyclic rubbing under the same friction conditions, the peak transmittance of the third silica composite antireflective coating sample remained at 97.10%, and the static water contact angle remained at 16.80°. The fourth silica composite antireflective coating sample, lacking the air cavity structure of hollow inorganic units, had an equivalent refractive index of 1. 28. The initial peak transmittance was 98.02%. After 80 cycles of cyclic friction under the same conditions, the peak transmittance of the fourth silica composite antireflective coating sample remained at 97.90%, indicating that the film lacked the low refractive index boundary required for optical impedance matching. The fifth silica composite antireflective coating sample, lacking a siloxane-bridged three-dimensional framework formed by gas-phase catalysis, had an initial peak transmittance of 98.85%. After 30 cycles of cyclic friction under the same conditions, particle exfoliation occurred due to the accumulation constraint between nanoparticles relying solely on intermolecular forces or hydrogen bonds, resulting in an increase in the surface static water contact angle to 31.07°. Furthermore, its peak transmittance decreased after 80 cycles of cyclic friction. Up to 94.20%, the synergistic effect of component ratio regulation and gas-phase interface chemical enhancement provides shear wear resistance physical properties exceeding the sum of single components. Fourier transform infrared spectroscopy was used to test the second silica composite antireflection coating sample in the wavenumber range of 400 cm⁻¹ to 4000 cm⁻¹. The infrared absorption spectrum of the second silica composite antireflection coating sample showed an absorption peak at 1080 cm⁻¹ representing the asymmetric stretching vibration of silicon-oxygen bonds, and at 800 cm⁻¹ representing the symmetric stretching vibration of silicon-oxygen bonds. Furthermore, the ratio of the absorption peak area at 960 cm⁻¹, representing the stretching vibration of surface-active silanol groups, to the absorption peak area at 1080 cm⁻¹ was 0.12. It was confirmed that hollow silica nanoparticles and solid silica nanoparticles form a stable inorganic siloxane covalent network structure at the particle accumulation contact points through a dehydration condensation reaction. After undergoing five free-falling gravel impact tests and 30 minutes of continuous high-pressure flowing water scouring, the physical thickness of the second silica composite antireflective coating sample remained at 110.37 nm, with an equivalent transmittance of greater than or equal to 98% in the visible light band. Furthermore, no mechanical peeling or porous framework collapse was observed on the coating surface.

[0058] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A method for preparing a silica composite antireflective coating, characterized in that, Includes the following steps: Step S101: Hollow silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 40nm to 60nm, dispersed in anhydrous ethanol medium, is mixed with solid silica sol with a mass percentage concentration of 1% to 3% and an average particle size of 15nm to 25nm, dispersed in anhydrous ethanol medium, at a volume ratio of 40:60 to 60:

40. The mixture is then homogenized and stirred at a speed of 300rpm to 500rpm for 30min to 60min to obtain a composite silica coating solution. Step S102: The composite silica coating solution is coated onto the surface of a washed and dried glass substrate by an immersion method. The immersion method is controlled at a pulling speed of 100 mm / min to 150 mm / min and the relative humidity of the coating environment is 40% to 50%. After coating, the coated glass substrate is placed in an oven at 60°C to 80°C and dried for 10 min to 15 min to obtain a porous composite primary film. Step S103: Place the porous composite primary membrane in a muffle furnace and heat it to a calcination temperature of 450°C to 550°C at a heating rate of 5°C / min. Then, calcine it at the calcination temperature for 1 to 2 hours. After calcination, control the muffle furnace and the porous composite primary membrane to cool to room temperature to obtain a heat-treated porous composite membrane. In step S104, the heat-treated porous composite membrane is moved into a sealed reaction chamber, and anhydrous ammonia gas is injected into the sealed reaction chamber. The ammonia gas concentration in the sealed reaction chamber is controlled to be 0.05 mol / L to 0.2 mol / L, the pressure in the sealed reaction chamber is maintained at 0.1 MPa to 0.12 MPa, the reaction environment temperature is set to 25℃ to 40℃, and the temperature is maintained for 20 min to 40 min. The injected anhydrous ammonia gas diffuses and penetrates to the particle interface contact sites in the heat-treated porous composite membrane to obtain a silica composite antireflective coating.

2. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, In step S101, the preparation steps of hollow silica sol include: mixing anhydrous ethanol with deionized water and ammonia water with a mass percentage concentration of 25%, adding hexadecyltrimethylammonium bromide as a soft template, stirring in a water bath at 30°C to 40°C for 30 min, adding tetraethyl silicate and reacting for 2 h to obtain primary silica with a soft template, centrifuging and washing the primary silica, calcining it at 550°C for 4 h to remove the soft template, and then dispersing it in anhydrous ethanol to obtain hollow silica sol.

3. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, Step S101 includes the following sub-steps: Step S1011, anhydrous ethanol and hollow silica sol are mixed and stirred for 10 minutes at a speed of 200 rpm to obtain a first premixed liquid; Step S1012, solid silica sol is added to the first premixed liquid, the speed is increased to 400 rpm and homogenized and stirred for 30 minutes to obtain a composite silica coating liquid.

4. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, In step S101, the preparation steps of solid silica sol include: mixing anhydrous ethanol with deionized water and ammonia water with a mass percentage concentration of 25%, stirring at 25°C for 15 min, adding tetraethyl silicate and stirring continuously for 6 h to obtain solid silica sol.

5. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, In step S102, the cleaning step of the glass substrate includes: immersing the glass substrate in a 5% sodium hydroxide solution and ultrasonically cleaning for 20 minutes, rinsing with deionized water until the water discharged from the surface is neutral, and finally drying in an oven at 80°C.

6. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, In step S102, when the glass substrate is lifted using the immersion method, the lifting speed is set to 120 mm / min, and the relative humidity of the coating environment is adjusted to 45%.

7. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, In step S102, the coated glass substrate is placed in an oven at 70°C and dried continuously for 12 minutes.

8. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, In step S104, anhydrous ammonia gas is continuously introduced into the sealed reaction chamber through the gas valve at the bottom of the sealed chamber, and the total internal pressure in the sealed reaction chamber is adjusted to 0.11 MPa.

9. The method for preparing a silica composite antireflective coating according to claim 1, characterized in that, After step S104, a film cleaning step is also included: the obtained silica composite antireflection coating is immersed in deionized water for 10 minutes and then dried with high-pressure pure nitrogen gas to remove the free ammonia molecules remaining on the surface of the silica composite antireflection coating.

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