Hydrophobic and oleophobic modification and anti-fingerprint application of antireflection coating based on porous structure

Abstract

This invention relates to the field of anti-fingerprint coating technology, and particularly to the hydrophobic and oleophobic modification of anti-reflective coatings based on porous structures and their anti-fingerprint applications. The method includes the following steps: First, a chitin nanofiber (ChNFs) suspension is prepared; then, methyltrimethoxysilane (MTMS) is introduced as a crosslinking agent, and MTMS-crosslinked ChNFs coatings with different water contents are placed in a gradient freezing temperature environment for treatment. This causes the chitin nanofibers to form a multi-nanoporous structure due to ice crystal repulsion, resulting in a substrate coated with a chitin nanofiber-based anti-reflective coating; subsequently, a vapor deposition method is used to modify the coating with perfluorodecyltriethoxysilane as a low-surface-energy modifier to achieve hydrophobic and oleophobic properties, thus imparting anti-fingerprint functionality while maintaining the anti-reflective properties. The single-layer anti-reflective coating of this invention achieves integrated functions of "high-efficiency anti-reflection, anti-fingerprint, environmentally friendly, and stable and durable," while providing a feasible and scalable technical path for the controllable preparation of high-performance composite coatings.

Description

Technical Field

[0001] This invention relates to the field of anti-fingerprint coating technology, and in particular to the hydrophobic and oleophobic modification of anti-reflective coatings based on porous structures and their anti-fingerprint applications. Background Technology

[0002] In recent years, interactive touch screen displays have become increasingly popular in portable electronic devices such as smartphones, tablets, and laptops, as well as in industrial control terminals, automotive display systems, and medical devices. They have become an indispensable core component in people's production and daily life. However, touch screens face a key challenge that has not been completely resolved in the process of frequent use: the inevitable accumulation of fingerprint residue. Fingerprint residue is a complex system composed of sweat (containing water, electrolytes, and other hydrophilic substances) and sebum (containing fatty acids and other lipophilic substances) secreted by the skin. Its adhesion to the screen surface not only significantly reduces the visual clarity of the display and causes glare interference, but also affects touch sensitivity and operation feel, seriously weakening the user experience. In addition, long-term fingerprint residue is prone to bacterial growth, and repeated wiping may cause screen scratches, further shortening the lifespan of the device.

[0003] To address this pain point, anti-fingerprint coatings have become a research hotspot in recent years. Their core objective is to minimize the adhesion of fingerprint residues and environmental contaminants by controlling the surface chemical composition and microstructure, thereby reducing cleaning frequency and maintenance costs while ensuring the optical performance and lifespan of display devices. An ideal anti-fingerprint coating needs to possess both hydrophobic and oleophobic properties, simultaneously inhibiting the adhesion and spread of water-based (sweat) and oil-based (sebum) contaminants. Meanwhile, anti-reflective coatings, as a key technology for improving the optical performance of display devices, can significantly improve screen transmittance and visual contrast by reducing interfacial refractive index differences and light reflection loss. However, traditional anti-reflective coatings often focus on optical performance optimization and generally suffer from high surface energy, susceptibility to contamination, and prominent fingerprint residue problems. Developing a coating that combines efficient anti-reflective and anti-fingerprint functions with environmental friendliness and excellent stability has become a core direction for meeting the practical application needs of display devices. Summary of the Invention

[0004] The purpose of this invention is to provide hydrophobic and oleophobic modification and anti-fingerprint application of antireflective coatings based on porous structures, so as to solve the problems mentioned in the background art that traditional antireflective coatings focus on optical performance optimization and generally have high surface energy, are easy to get dirty, and have prominent fingerprint residue.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure, comprising the following steps:

[0006] S1. Weigh chitin powder and maleic anhydride powder at a mass ratio of 1:5, mix and seal, and react at 120°C for 3 hours in an oven. The reaction product is then centrifuged and washed until the supernatant is neutral to remove unreacted maleic anhydride and obtain esterified chitin product.

[0007] S2. Take the esterified chitin product from step S1, add a 35% NaOH solution, and react at 90℃ for 4 hours to achieve partial deacetylation of the acetylamino group on the chitin molecular chain. The reaction product is centrifuged and washed until the dispersion is neutral to remove residual NaOH.

[0008] S3. The washed esterified-partially deacetylated chitin product was diluted to a dispersion with a mass fraction of 0.05 wt%, the pH was adjusted to 3.5 with acetic acid, and then subjected to ultrasonic nanofiberization treatment to obtain a uniform and stable chitin nanofiber (ChNFs) dispersion.

[0009] S4. The ChNFs dispersion was mixed with methyltrimethoxysilane (MTMS) at a mass ratio of 8:1 and stirred continuously for 2 hours at room temperature (25±2℃) and stirring rate (300r / min) to obtain the ChNFs / MTMS aqueous dispersion.

[0010] S5. Select an ultra-thin, high-transparency glass slide as the substrate, and clean it with deionized water and anhydrous ethanol for 20 minutes each, and dry it at 60°C for 30 minutes before use.

[0011] S6. Take 0.8 mL of ChNFs / MTMS aqueous dispersion and uniformly cast it onto the surface of the pretreated glass slide. Dry it at 60℃ for 1 h to obtain an MTMS cross-linked ChNF coating. Then, equilibrate at 93% relative humidity and room temperature for 8 h to allow the coating to reach a stable moisture content. Next, place the glass slide with the coating in a refrigerator and freeze it at -60℃ for 5 h. Finally, transfer it to an oven and thaw and dry it at 60℃ to obtain a multi-nanoporous MTMS cross-linked ChNFs antireflective coating.

[0012] S7. Place a glass slide with an MTMS cross-linked ChNF antireflective coating in a chemical vapor deposition reactor, with the coated surface facing down and a vertical distance of 8 cm from the bottom of the reactor. Inject 80 μL of perfluorodecyltriethoxysilane (PFDTES) as a fluorination modifier into the bottom of the reactor. Place the reactor in a vacuum drying oven, evacuate to 85 kPa, heat to 120 °C, and set different times for modification. Then, allow it to cool naturally to room temperature and release the vacuum to obtain a single-layer antireflective and anti-fingerprint coating (P-ChNF). x ).

[0013] Preferably, in steps S1 and S2, the centrifugal washing speed is 6500 r / min and the centrifugation time is 5 min.

[0014] Preferably, in step S5, the ultrasonic power is 500W.

[0015] Preferably, in step S6, the ChNFs / MTMS aqueous dispersion completely covers the substrate area of ​​the glass slide, and the stable state of the moisture content is that the moisture content is controlled at 44.4%.

[0016] Preferably, in step S6, a nanoporous structure is constructed using a freeze casting method. The freeze casting method imparts a coating with a maximum porosity of 1.28 and a minimum refractive index, providing a structural basis for antireflective properties.

[0017] Preferably, in step S7, the different time settings are 0 min, 15 min, 30 min, 45 min, and 60 min.

[0018] A hydrophobic and oleophobic modified antireflective coating, wherein the coating has a nanoporous structure, a water contact angle ≥150°, an oleic acid contact angle ≥118°, a transmittance ≥95% at a wavelength of 550nm, and a reflectance ≤3.1%.

[0019] The application of hydrophobic and oleophobic modified antireflective coatings in touch screen display devices, wherein the coating is applied to the surface of glass or tempered glass to improve light transmittance, suppress reflection, and prevent fingerprint adhesion.

[0020] Preferably, the touch screen display device includes smartphones, tablets, vehicle display systems, and industrial control terminals.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. Using natural and renewable chitin nanofibers as the core raw material, ChNFs dispersions were prepared through esterification modification, partial deacetylation, and ultrasonic nanofiberization. Then, a low refractive index (1.28) nanoporous bottom coating was constructed by MTMS crosslinking and freeze casting. Combined with low surface energy modification by chemical vapor deposition, a single-layer integrated coating with both high-efficiency antireflection and superhydrophobic anti-fingerprint functions was successfully prepared. The coating has a transmittance of 95.3% and a reflectance of only 3.1% at a characteristic wavelength of 550nm. The transmittance is 5.0% higher than that of a blank glass slide, and the reflection loss is reduced by more than 67%. It also maintains excellent antireflection performance in the incident angle range of 0°-75°. Even at the extreme incident angle of 75°, it still has a transmittance gain of 3.4% and a low reflectance of 6.8%. It effectively solves the pain points of traditional antireflection coatings being easy to get dirty and the insufficient optical performance of anti-fingerprint coatings. At the same time, by suppressing the interference of interface reflected light, it significantly improves the visual clarity of display devices.

[0023] 2. The coating possesses excellent superhydrophobic and oleophobic properties, and is modified by fluorination of P-ChNF for 60 minutes. 60 The coating has a water contact angle of 153° and an oleic acid contact angle of 118°, which enables fingerprint residue to form discrete droplets without the formation of continuous lines. This significantly reduces the amount and visibility of fingerprints, reduces cleaning frequency and maintenance costs, and avoids the growth of bacteria from fingerprint residue and screen scratches caused by repeated wiping, thus indirectly extending the lifespan of display devices. In addition, the coating has high transparency and no visual defects such as yellowing or haziness, fully meeting the stringent requirements of display devices for coating appearance.

[0024] 3. The core raw material, chitin nanofiber, is widely available, biocompatible, and environmentally degradable. The preparation process is simple to operate and the parameters are easy to control. It does not require complex and expensive equipment, and has the advantages of being both environmentally friendly and low-cost. At the same time, the coating has strong application compatibility and can be adapted to various transparent substrates such as glass and tempered glass. It is suitable for various display devices such as smartphones, automotive display systems, and medical devices, and will not affect the touch response sensitivity and display quality of the display devices. It achieves the integration of functions of "high efficiency anti-reflection - anti-fingerprint - environmentally friendly - stable and durable", providing a new green solution for the surface protection of display devices and has broad practical application prospects. Attached Figure Description

[0025] Figure 1 P-ChNF prepared under different conditions was constructed for this invention. x Transmittance variation of coated glass slide;

[0026] Figure 2 P-ChNF prepared under different conditions was constructed for this invention. x A diagram showing the variation in reflection of the coated glass slide;

[0027] Figure 3 This invention is free of P-ChNF 60 Coating and coated with P-ChNF 60 Comparison of the anti-reflective properties of coated glass slides;

[0028] Figure 4 This is a comparison diagram of the contact angles of water droplets and oil droplets under different modification times according to the present invention;

[0029] Figure 5 P-ChNF at different modification times according to the present invention x The coating's anti-fingerprint properties, anti-fingerprint appearance, and P-ChNF x High-magnification image of fingerprints remaining on the coating;

[0030] Figure 6 Comparison of oil-red fingerprint residue on the surface of a smartphone equipped with a tempered glass screen protector according to the present invention. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1-6 This invention provides a technical solution: a method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure, comprising the following steps:

[0033] Step 1: Preparation of Chitosan Nanofibers

[0034] Chitosan was first modified by esterification with maleic anhydride. Chitosan powder and maleic anhydride powder were accurately weighed at a mass ratio of 1:5, thoroughly mixed, and sealed in an Erlenmeyer flask. The flask was placed in an oven and reacted at 120℃ for 3 hours. After the reaction, an appropriate amount of purified water was added to the flask, the reaction product was stirred and dispersed, and then centrifuged (6500 rpm, 5 minutes). Washing was repeated until the pH of the supernatant was neutral to remove unreacted maleic anhydride. 1 g of the esterified chitosan product was weighed and added to 25 mL of a 35% (mass fraction) NaOH solution. The mixture was stirred thoroughly until uniformly dispersed. The mixture was then placed in a constant-temperature water bath and reacted at 90℃. After 4 hours, the deacetylation of some acetylamino groups on the chitin molecular chain was achieved. After the reaction was completed, the system was cooled to room temperature, and the precipitate was collected by centrifugation (6500 r / min, 5 min). An appropriate amount of purified water was added to the precipitate, and the mixture was stirred and dispersed before centrifugation and washing. The above operation was repeated until the pH of the dispersion was neutral. The residual NaOH was removed, and the washed esterified-partially deacetylated chitin product was diluted with purified water to prepare a dispersion with a mass fraction of 0.05 wt%. The pH was adjusted to 3.5 with acetic acid, and the diluted dispersion was subjected to ultrasonic nanofiberization treatment to obtain a uniform and stable chitin nanofiber (ChNFs) dispersion.

[0035] Step 2: Preparation of Chitosan Nanofiber-Based Antireflective Coating

[0036] ChNFs suspension and MTMS were mixed at a mass ratio of 8:1 and placed on a magnetic stirrer. The mixture was stirred continuously for 2 hours at room temperature (25±2)℃ and a stirring rate of 300 r / min to ensure uniform dispersion of MTMS in the ChNFs suspension, ultimately obtaining a stable and homogeneous ChNFs / MTMS aqueous dispersion for later use. Ultrathin, high-transparency glass slides were selected as the coating substrate and ultrasonically cleaned sequentially with deionized water and anhydrous ethanol for 20 minutes each time at a power of 500 W to thoroughly remove oil, dust, and other impurities from the substrate surface. After cleaning, the slides were dried in a 60℃ oven for 30 minutes to remove residual moisture and cooled to room temperature for later use. The coating was first prepared using a casting method. 0.8 mL of the ChNFs / MTMS aqueous dispersion was pipetted evenly onto the pre-treated substrate. After processing, the surface of the glass slide was ensured to completely cover the substrate area with the dispersion. The glass slide was then transferred to a 60℃ electric thermostatic drying oven for 1 hour to obtain an MTMS cross-linked ChNF coating. After removal, it was placed in a constant temperature and humidity chamber and equilibrated for 8 hours at a relative humidity of 93% and room temperature to allow the coating to reach a stable moisture content (the final moisture content was controlled at 44.4%). Next, the glass slide with the coating was placed in an ultra-low temperature freezer and frozen at −60℃ for 5 hours to construct a nanoporous structure using a cryogenic casting method. After freezing, it was quickly transferred to a 60℃ oven for 20 minutes to thaw and dry simultaneously. The cryogenic casting parameters (moisture content 44.4%, freezing temperature -60℃) showed that the coating could obtain the highest porosity and the lowest refractive index (1.28), laying the foundation for the porous structure for anti-reflection performance.

[0037] Step 3: Superhydrophobic modification of single-layer antireflective coating

[0038] To reduce the surface energy of the aforementioned multi-nanoporous MTMS cross-linked ChNF antireflective coating and impart anti-fingerprint properties, fluorination modification was performed using chemical vapor deposition. The specific process is as follows:

[0039] First, a glass slide with an MTMS cross-linked ChNF antireflective coating was placed in a self-made chemical vapor deposition reactor. The reactor was then placed in a vacuum drying oven. The position of the slide was adjusted so that the vertical distance between it and the bottom of the reactor was controlled at 8 cm, with the coated side facing down, to ensure sufficient contact between the coating surface and the fluorination modifier vapor, improving the uniformity of modification. 80 μL of perfluorodecyltriethoxysilane (PFDTES) was precisely injected into the bottom of the reactor as the fluorination modifier using a pipette. After closing the vacuum drying oven door, a vacuum of 85 kPa was created, and the oven temperature was raised to 120°C. Modification was performed for different durations under these temperature and vacuum conditions. After modification, the heating device was turned off, and the reaction system was allowed to cool naturally to room temperature. The vacuum was slowly released, and the coating was removed, yielding the modified antireflective and anti-fingerprint coating, named P-ChNF. x Coating (where "x" represents the vapor deposition modification time, specifically x = 0 min, 15 min, 30 min, 45 min, 60 min).

[0040] Furthermore, such as Figure 1 As shown, Figure 1 The transmittance spectra of P-ChNFx coatings prepared at different modification times on glass slides are shown, along with the transmittance variation under different incident light angles. Figure 1 (a) It can be seen that all P-ChNF coatings x The light transmittance of the coated glass slides was significantly higher than that of the uncoated blank glass slides, indicating that the fluorinated P-ChNFx coating still maintains excellent antireflective properties. The core reason for this performance advantage lies in the fact that the freeze-casting process constructs a rich and uniform nanoporous structure in the ChNFs-based coating. This structure effectively reduces the refractive index gradient difference between air, coating, and glass substrate, reducing interfacial light reflection loss, thereby achieving a significant improvement in light transmittance. Specifically, when the modification time is 60 min, the P-ChNFx coating exhibits significantly higher transmittance than the uncoated blank glass slides. 60 The coating exhibits optimal antireflection performance, maintaining high transmittance across the entire visible light spectrum. Specifically, it achieves 95.3% transmittance at the characteristic wavelength of 550 nm, representing a transmittance gain of approximately 5.0% compared to a blank glass slide (transmittance at 550 nm is approximately 90.3%), a 25.0% improvement. This improvement stems not only from the higher porosity and superior pore structure (refractive index as low as 1.28) imparted by the cryogenic casting process, but also from the effective preservation of the coating's porous structure during chemical vapor deposition modification. The modification only introduces low surface energy fluorinated groups onto the coating surface, without causing blockage of the nanopores, thus ensuring the integrity of the antireflection function.

[0041] Most importantly, the all-around anti-reflective capability of anti-reflective coatings is crucial for practical applications in real life. Figure 1 (b) Demonstrates coating of P-ChNF 60 The correlation between the transmittance of the coated slide and the incident angle is as follows: compared with vertical incidence (0°), when the incident angle gradually increases from 0° to 75°, the transmittance of the coating decreases slightly but still remains at a high level; under the extreme incident angle of 75°, the transmittance gain at 550nm is still as high as 3.4%.

[0042] Furthermore, such as Figure 2 As shown, Figure 2 The reflectance spectra of P-ChNFx coatings prepared at different modification times on glass slides are shown, as well as the reflectance variation under different incident light angles. The antireflection performance of the coatings is systematically evaluated from the perspective of reflection suppression. Figure 2 The reflectance test results in (a) further demonstrate that, compared to the reflectance of the glass slide (approximately 9.4% at 550 nm), the reflectance of the glass slide coated with P-ChNF is significantly lower. x When coated, the reflectivity is significantly reduced; the reflectivity of a blank glass slide at 550 nm is approximately 9.4%, while that of a slide coated with P-ChNF is significantly higher. 60 After coating, the reflectivity at this wavelength is significantly reduced to 3.1%, and the reflection loss is reduced by more than 67%, achieving full-band reflection suppression compared to a blank glass slide.

[0043] Furthermore, Figure 2 (b) The results of reflectance changes under different incident angles further demonstrate that P-ChNF 60 The coating possesses omnidirectional anti-reflective properties. Under test incident angles of 15°, 30°, 45°, 60°, and 75°, the P-ChNF coating... 60 The reflectivity of the coated slides was significantly lower than that of the blank slides, and the increase in reflectivity was gradual with the increase of the incident angle. Even at the extreme incident angle of 75°, the reflectivity was only 6.8%, which was lower than the 27.7% of the blank slides at the same angle. This characteristic indicates that the P-ChNFx coating has good all-around anti-reflection performance and is expected to be used in different observation angle scenarios to effectively avoid the decrease in visual clarity caused by changes in the incident angle.

[0044] Furthermore, such as Figure 3 As shown, the coating's transparency and its anti-reflective effect in practical applications are important and intuitive indicators for evaluating its application potential. Figure 3 (a) Showing blank glass slides and P-ChNF coated glass slides 60 The comparison images of the coated glass sheets show that the differences between the two are visually indistinguishable, indicating that P-ChNF... 60The coating exhibits excellent transparency and does not exhibit significant visual defects (such as yellowing or haziness) due to the nanoporous structure or fluorination modification, meeting the stringent requirements of optical devices for coating appearance. This provides a basis for further visual verification of the coating's antireflective properties. Figure 3 (b) Showing a bare glass slide (top) and a P-ChNF coated slide. 60 Comparison photographs of coated glass slides (bottom) under illumination show the bright area projected by the chandelier clearly. The bare glass slide, due to strong light reflection, obscures the text beneath the lamplight, making it completely illegible. In contrast, the P-ChNF coated slide... 60 The coated glass slide exhibits significantly suppressed surface reflection, while text remains clearly visible within the lamplight area. This intuitive phenomenon aligns with the previous quantitative reflectance test results (constructed using P-ChNF). 60 The high degree of agreement between the coated glass slide and the reduced reflectance at 550nm (from 9.4% to 3.1%) further confirms the excellent anti-reflection performance of the P-ChNF coating. By suppressing interference from interface reflected light, it effectively improves visual clarity in practical applications, providing visualization support for its use in devices requiring clear visual presentation, such as smart touch screens and display panels.

[0045] Furthermore, wettability, as a core evaluation indicator of anti-fingerprint performance, directly reflects the coating's ability to resist water-based and oil-based contaminants, such as... Figure 4 As shown, tests were conducted on clean glass slides, unmodified ChNFs-based coatings (0 min deposition), and P-ChNFs prepared at different modification times. x The water contact angle and oleic acid contact angle of the coating, such as Figure 4 (a) Due to the presence of hydroxyl groups on the surface of the clean glass slide, it exhibits hydrophilicity, with a water contact angle of approximately 31°. The unmodified ChNF-based coating (0 min deposition) is rich in hydrophilic groups such as hydroxyl, carboxyl, acetamino, and amino groups, with a water contact angle of approximately 29°. After modification by PFDTES chemical vapor deposition, P-ChNF... x The water contact angles of the coatings all showed a significant increase, exhibiting a trend of first increasing and then stabilizing with modification time. After 30 minutes of modification, the water contact angle of the P-ChNF30 coating increased to approximately 135°, achieving hydrophobic properties. Extending the modification time to 60 minutes, the P-ChNF... 60 The water contact angle of the coating is approximately 153°, meeting the standard of a superhydrophobic contact angle >150°. The modification time was further extended to 75 minutes for P-ChNF. 60 The water contact angle of the coating is approximately 155°, similar to that of P-ChNF. 60 The coating showed no significant difference, indicating that PFDTES had been fully grafted onto the coating surface by 60 minutes of modification, and the oleic acid contact angle was as shown. Figure 4(b) The oleic acid contact angle of the bare glass slide is approximately 21°, exhibiting strong oleophilicity. After coating with an unmodified ChNFs coating (0 min deposition), the oleic acid contact angle is 18°, showing even more significant oleophilicity. This phenomenon is attributed to the hydrogen bonding between the hydrophilic groups on the ChNFs coating surface and the oleic acid molecules, as well as the van der Waals attraction between the coating surface and the oleic acid molecules, resulting in complete spread of oleic acid on the surface. After modification, the oleic acid contact angle of the P-ChNFx coating is improved. 45 The oil contact angle of the coating increased to 95.3°, initially exhibiting oleophobic properties, P-ChNF 60 The coating achieves an oleic acid contact angle of 118°, significantly enhancing its oleophobic properties. Figure 4 The illustrations in (a) and (b) show the effects of 50 μL water and oil droplets on P-ChNF. 60 The coating surface remained nearly spherical and did not spread, which visually confirms its excellent dual-repellent properties (hydrophobic and oleophobic).

[0046] Furthermore, such as Figure 5 As shown, the system evaluates its anti-fingerprint performance through fingerprint residue tests simulating real-world usage scenarios. Figure 5 This study showcases the anti-fingerprint appearance of clean glass slides and P-ChNFx coating surfaces at different modification times, as well as high-magnification details of residual fingerprints on the P-ChNFx coating surfaces. Macroscopic images reveal clearly distinguishable fingerprint traces on both bare glass slides and unmodified coating surfaces, with complete fingerprint patterns. This is closely related to the strong hydrophilicity and oleophilicity of both surfaces. The aqueous component of the fingerprint spreads rapidly, while the oil component is tightly adsorbed, resulting in a strong interaction between the residue and the substrate. In stark contrast, fingerprint visibility is significantly suppressed on all P-ChNFx coating surfaces, and fingerprint residue decreases with prolonged modification time. 45 Faint fingerprint traces remained on the coating surface, but the patterns began to blur. When the modification time was extended to 60 minutes, P-ChNF... 60 Fingerprints on the coating surface are almost invisible. High-magnification images show that only a very small amount of dispersed sebum droplets remain on the coating surface, with no continuous fingerprint patterns forming. Based on the combined wettability and anti-fingerprint performance test results, a correlation can be established: the anti-fingerprint effect of the coating is positively correlated with the water / oil contact angle. When the water contact angle of the coating is ≈150° and the oil contact angle is ≈120°, the amount and visibility of fingerprint residue are significantly reduced. However, when the water contact angle is <140° and the oil contact angle is <110° (such as P-ChNF), the fingerprint effect is significantly reduced. 45 Even with a coating, fingerprint residue still exists. This indicates that the dihydrophobic properties are a prerequisite for the coating to achieve anti-fingerprint performance. Modification, by regulating the surface chemical composition, achieves synergistic optimization of wettability and anti-fingerprint performance.

[0047] Furthermore, to further explore P-ChNF x The practical application potential of the coating will enable P-ChNF to achieve optimal performance. 60 The coating was applied to the surface of a tempered glass screen protector for smartphones to simulate fingerprint resistance and compatibility under real-world usage scenarios. Test results are as follows: Figure 6 As shown, Figure 6 (a) The surface of a smartphone with a clean, original tempered glass screen protector shows clearly visible red fingerprint marks after being pressed with oil-based fingerprints. The fingerprint texture is detailed and severely affects the visual clarity of the screen. Figure 6 (b) Coating with P-ChNF 60 The tempered glass screen protector with the coating significantly suppresses the amount of oil-based fingerprints on the smartphone surface under the same conditions. Only faint traces are visible, with no obvious continuous lines, resulting in a significant improvement in visual clarity. This result is consistent with the previous description of the P-ChNF coating. 60 The fingerprint resistance test results of the glass slide substrate were consistent, confirming that P-ChNF... 60 The coating maintains excellent anti-fingerprint properties on the surface of actual electronic devices, effectively preventing the accumulation of smudges and fingerprints.

[0048] Most importantly, compatibility testing shows that P-ChNF 60 The coating did not negatively impact the core performance of the smartphone touchscreen. On one hand, the coating's high transparency and low haze ensured the original display quality of the screen, preventing issues such as blurry images and color distortion. On the other hand, the coating did not affect the touchscreen's electronic response sensitivity. Letter input tests verified that all 26 English letters could be input smoothly, with a touch response speed of ≤50ms, indistinguishable from the original screen without the coating. Furthermore, combined with the anti-reflective performance test results mentioned earlier, P-ChNF... 60 The coating not only provides fingerprint resistance but also reduces screen reflection interference, further enhancing the visual experience.

[0049] In summary, the application verification of P-ChNF coating in smartphone screen protectors shows that it not only has excellent anti-fingerprint and anti-smudge performance, but also takes into account display quality and touch compatibility, while playing an anti-reflective role. It has important practical application value and promotion potential in the field of smart electronic devices.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure, characterized in that, Includes the following steps: S1. Weigh chitin powder and maleic anhydride powder at a mass ratio of 1:5, mix and seal, and react at 120°C for 3 hours in a drying oven. The reaction product is then centrifuged and washed until the supernatant is neutral to remove unreacted maleic anhydride and obtain esterified chitin product. S2. Take the esterified chitin product from step S1, add a 35% NaOH solution, and react at 90℃ for 4 hours to achieve the deacetylation of some acetylamino groups on the chitin molecular chain. The reaction product is centrifuged and washed until the dispersion is neutral to remove residual NaOH. S3. The washed esterified-partially deacetylated chitin product was diluted to a dispersion with a mass fraction of 0.05 wt%, the pH was adjusted to 3.5 with acetic acid, and then subjected to ultrasonic nanofiberization treatment to obtain a uniform and stable chitin nanofiber (ChNFs) dispersion. S4. The ChNFs dispersion was mixed with methyltrimethoxysilane (MTMS) at a mass ratio of 8:1 and stirred continuously for 2 hours at room temperature (25±2℃) and stirring rate (300r / min) to obtain the ChNFs / MTMS aqueous dispersion. S5. Select an ultra-thin, high-transparency glass slide as the substrate, and clean it with deionized water and anhydrous ethanol for 20 minutes each, and dry it at 60°C for 30 minutes before use. S6. Take 0.8 mL of ChNFs / MTMS aqueous dispersion and uniformly cast it onto the surface of the pretreated glass slide. Dry it at 60 °C for 1 h to obtain an MTMS cross-linked ChNF coating. Then, equilibrate at 93% relative humidity and room temperature for 8 h to allow the coating to reach a stable moisture content. Next, place the glass slide with the coating in an ultra-low temperature freezer and freeze it at -60 °C for 5 h. Finally, transfer it to an oven and thaw and dry it at 60 °C to obtain a multi-nanoporous MTMS cross-linked ChNF antireflective coating. S7. Place a glass slide with an MTMS cross-linked ChNF antireflective coating in a chemical vapor deposition reactor, with the coated surface facing down and a vertical distance of 8 cm from the bottom of the reactor. Inject 80 μL of perfluorodecyltriethoxysilane (PFDTES) as a fluorination modifier into the bottom of the reactor. Place the reactor in a vacuum drying oven, evacuate to 85 kPa, heat to 120 °C, and set different times for modification. Then, allow it to cool naturally to room temperature and release the vacuum to obtain a single-layer antireflective and anti-fingerprint coating (P-ChNF). x ).

2. The method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure according to claim 1, characterized in that, In steps S1 and S2, the centrifugal washing speed is 6500 r / min and the centrifugation time is 5 min.

3. The method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure according to claim 1, characterized in that, In step S5, the ultrasonic power is 500W.

4. The method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure according to claim 1, characterized in that, In step S6, the ChNFs / MTMS aqueous dispersion completely covers the substrate area of ​​the glass slide, and the stable state of the moisture content is that the moisture content is controlled at 44.4%.

5. The method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure according to claim 1, characterized in that, In step S6, a nanoporous structure is constructed using a cryogenic casting method. The cryogenic casting method imparts a minimum refractive index of 1.28 to the coating, providing a structural basis for its antireflective properties.

6. The method for preparing a hydrophobic and oleophobic modified antireflective coating based on a porous structure according to claim 1, characterized in that, In step S7, the different time settings are 0 min, 15 min, 30 min, 45 min, and 60 min.

7. A hydrophobic and oleophobic modified antireflective coating prepared by the method according to any one of claims 1-6, characterized in that, The coating has a nanoporous structure, a water contact angle ≥150°, an oleic acid contact angle ≥118°, a transmittance ≥95% at a wavelength of 550nm, and a reflectance ≤3.1%.

8. The application of the hydrophobic and oleophobic modified antireflective coating as described in claim 7 in a touch screen display device, characterized in that, The coating is applied to the surface of glass or tempered glass to improve light transmittance, suppress reflection, and prevent fingerprints from adhering.

9. The application of the hydrophobic and oleophobic modified antireflective coating according to claim 8 in a touch screen display device, characterized in that, The touchscreen display devices include smartphones, tablets, vehicle display systems, and industrial control terminals.

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