Structural Colored Fabrics and Their Preparation Methods

Abstract

This invention relates to structural colored fabrics and their preparation method. The preparation method includes the following steps: (1) dispersing rough-surfaced hollow nanospheres in an aqueous solution, and adding alkali solution for modification to obtain photonic nano-pigment; (2) preparing a photonic nano-pigment solution by mixing the photonic nano-pigment, aqueous acrylic emulsion, carbon black, tannic acid, and water; (3) immersing the fabric in the photonic nano-pigment solution, and then placing it in an oven for heat treatment to obtain structural colored fabric. This invention utilizes the characteristics of photonic nano-pigment—no assembly required and single-sphere color generation—to develop a simple and efficient one-step dyeing method. By introducing an aqueous acrylic emulsion binder and the hydrogen-bonding crosslinking agent tannic acid, the interaction between the photonic nano-pigment and the fabric is enhanced. The photonic nano-pigment can be uniformly attached to the yarn surface, and the prepared structural colored fabric has high saturation, good color fastness, softness, and excellent air permeability.

Description

Technical Field

[0001] This invention belongs to the field of structural color material application and textile printing and dyeing structural color generation technology, specifically relating to a structural color fabric and its preparation method and application. Background Technology

[0002] Fabric dyeing has always played a vital role in the textile industry, reflecting advanced human aesthetic needs and cultural expression. All commercial colorants are based on organic dyes and pigments that selectively absorb light, generating significant amounts of wastewater pollution and toxic substances during the dyeing process. Furthermore, these chemical colorants are chemically unstable under light, easily discoloring or fading over time. In contrast, structural color originates from the interaction of visible light with periodic micro or nanostructures. Theoretically, as long as the micro or nanostructure remains intact, structural color will never fade. Moreover, structural color can be continuously adjusted across the entire visible light spectrum simply by changing the size and spacing of a set of materials. Therefore, as a clean and environmentally friendly alternative, structural color of fabrics is receiving increasing attention in the textile industry.

[0003] Structural color materials, due to their cleanliness, environmental friendliness, and resistance to fading, have become an ideal choice for eco-friendly dyeing. In many cases, researchers employ colloidal nanosphere self-assembly technology to prepare close-packed photonic crystals or amorphous photonic structures as structural colorants. However, in terms of practicality, they are difficult to replace dyes and pigments. Photonic crystals and amorphous photonic structures rely on complex and time-consuming self-assembly processes, which limits their commercialization and application. Furthermore, the assembly of these structures requires a large nanosphere load, which can affect the inherent wearing experience of textiles, such as breathability and softness. Achieving a balance between environmentally friendly dyeing and commercial practicality in fabric coloring using structural color materials remains an urgent goal.

[0004] Patent document CN113106749B discloses a method for preparing structural colored fabrics by self-assembling polystyrene microspheres coated with tannic acid onto the surface of a fabric. However, this method requires an assembly process of 2-4 hours, and the structural colored fabrics obtained by drop coating lose their breathability and softness, and cannot achieve one-time double-sided coloring. In addition, patent document CN109201438A discloses a method for preparing amorphous photonic crystal structures by blending monodisperse nanospheres, polymer emulsions with the same charge as the microspheres, and natural melanin such as carbon black, carbon nanotubes, graphene, or polydopamine under heat-assisted conditions. However, the structural colored fabrics prepared have problems such as poor color fastness and inability to be prepared on a large scale. Summary of the Invention

[0005] Based on the aforementioned shortcomings and deficiencies in the prior art, one of the objectives of this invention is to at least solve one or more of the aforementioned problems in the prior art. In other words, one of the objectives of this invention is to provide a structural colored fabric that meets one or more of the aforementioned requirements, as well as its preparation method and application.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a structurally colored fabric includes the following steps:

[0008] (1) A photonic nano-pigment was obtained by dispersing rough-surfaced hollow nanospheres in an aqueous solution and then modifying them with alkali solution.

[0009] (2) Photonic nano pigment, aqueous acrylic emulsion, carbon black, tannic acid and water are prepared into a photonic nano pigment solution;

[0010] (3) The fabric is immersed in a photonic nano pigment solution and then placed in an oven for heat treatment to obtain a structural color fabric.

[0011] As a preferred embodiment, in step (2), the photonic nano pigment in the photonic nano pigment solution has a mass fraction of 20-30 wt%, the aqueous acrylic emulsion has a mass fraction of 10-20 wt%, the carbon black has a mass fraction of 0.1-0.5 wt%, and the tannic acid has a mass fraction of 0.1-0.8 wt%.

[0012] As a preferred embodiment, in step (3), the fabric is immersed for 5 to 60 seconds and the heat treatment temperature of the oven is 50 to 90°C.

[0013] As a preferred embodiment, in step (1), the pH of the solution is adjusted to 10-12 with an alkaline solution.

[0014] As a preferred embodiment, in step (1), the alkaline solution is sodium carbonate, sodium bicarbonate, ammonia, or ammonium bicarbonate solution.

[0015] As a preferred embodiment, in step (1), the hollow nanospheres are hollow silicon dioxide, titanium dioxide, zirconium dioxide, tin dioxide, cerium dioxide, zinc oxide, copper oxide, or zinc sulfide.

[0016] As a preferred embodiment, in step (1), after adding alkali solution, the mixture is stirred and modified at 80-95°C.

[0017] As a preferred embodiment, the fabric substrate is cotton, polyester, polyester-cotton blend, polyester-spandex blend, wool-polyester blend, polyester-viscose blend, or polyester-cotton blend.

[0018] The present invention also provides a structural color fabric prepared by the preparation method described in any of the preceding embodiments, the structural color fabric having a double-sided structural color.

[0019] Compared with the prior art, the beneficial effects of this invention are:

[0020] (1) The photonic nano-pigment of the present invention is composed of hollow nanospheres with rough surfaces. It can generate non-iridescent structural colors independently without self-assembly and can be uniformly dispersed in water after modification. Through a one-step dyeing strategy, the photonic nano-pigment can be quickly and uniformly attached to the surface of fabric yarns to achieve high-quality double-sided structural coloring. At the same time, the hydrogen bond cross-linking network between the fabric and nanospheres is constructed by using water-based acrylic emulsion WA and tannic acid TA, which greatly improves the color fastness. In addition, since the nano-sized pigment does not clog the weaving pores of the fabric, the fabric still has good softness and breathability.

[0021] (2) The photonic nano pigments of the present invention provide a new approach for the large-scale preparation of structural colored fabrics. Each photonic nano pigment is an independent coloring unit, requiring no assembly process. This simple and efficient structural dyeing strategy of one-step dyeing has great commercial value. It combines the simplicity, versatility and scalability of traditional chemical pigment dyeing processes, while also achieving environmentally friendly dyeing. The nanoscale colorant brings excellent wearing experience to the structural colored fabric, such as breathability, softness, angle independence and excellent coverage. Its dyeing effect is close to that of traditional pigments and is very similar to the dyeing effect of dyes and pigments.

[0022] (3) The successful use of photonic nano pigments in the dyeing strategy of this invention is a major advancement in the field of ecological dyeing. Attached Figure Description

[0023] Figure 1 This is a flowchart of the method for preparing the structured colored fabric of Embodiment 1 of the present invention;

[0024] Figure 2 In the diagram, a is a schematic diagram of surface modification used to enhance the long-range electrostatic repulsion between nanospheres; b is a comparison of the aqueous solution of orange photonic nanopigment before and after modification (A: before modification, B: after modification, 0.05 g / ml); c is the particle size distribution of unmodified and modified H-SiO2 nanospheres; d is the zeta potential of unmodified and modified H-SiO2 nanospheres.

[0025] Figure 3 The adhesion enhancement diagram shows the network structure formed between TA, WA, and photonic nanopigments.

[0026] Figure 4In the diagram, a represents six structural dyed fabrics of different colors obtained through a one-step dyeing method; b and c represent the corresponding reflectance spectra of the front and back sides of the structural dyed fabrics, respectively; d represents digital photographs of green, blue, and magenta fabrics from different angles; and e, f, and g represent three-dimensional mapping projections of the reflectance spectra of green, blue, and magenta samples independent of angle, respectively.

[0027] Figure 5 In the image, a, b, and c are scanning electron microscope images of white cotton fabric, structured fabric with H-SiO2 photonic nano-pigment attached, and H-SiO2 / WA-TA structured fabric bonded with WA-TA, respectively.

[0028] Figure 6 In the figures, a and c are digital photographs and reflectance spectral changes of H-SiO2 / WA / cotton fabrics with different WA contents before and after friction; b and d are digital photographs and reflectance spectral changes of H-SiO2 / WA-TA / cotton fabrics with different TA contents before and after washing.

[0029] Figure 7 In the diagram, a and b are digital photographs of the H-SiO2 / cotton fabric and H-SiO2 / WA-TA / cotton fabric after durability testing, including 2 hours of water immersion, 50 brush washes, 45 minutes of washing, and 30 minutes of ultrasonic treatment; c shows the change in reflectance spectrum of the samples after durability testing in a and b; d is a digital photograph of the H-SiO2 / WA-TA / cotton fabric showing softness; e is a schematic diagram of the continuous tumble spinning process, including dye solution impregnation, heat drying, and fabric collection; f is a digital photograph of the structurally colored fabric prepared by the method in e.

[0030] Figure 8 A photograph illustrating the air permeability of the structured fabric prepared in Example 1 of this invention;

[0031] Figure 9 In the image, a and b are digital photographs and reflectance spectra of the structural colored fabrics prepared in Example 1 and Comparative Example 1, respectively; c and d are digital photographs and reflectance spectra of the structural colored fabrics prepared in Example 1 and Comparative Example 1 after rubbing, respectively.

[0032] Figure 10 In the figures, a and b are digital photographs and reflectance spectra of the structural colored fabrics prepared in Example 1 and Comparative Example 2, respectively; c and d are digital photographs and reflectance spectra of the structural colored fabrics prepared in Example 1 and Comparative Example 2 after rubbing, respectively.

[0033] Figure 11 In the image, a and b are digital photographs of the structured fabrics prepared in Example 1 and Comparative Example 3, respectively; c is the reflectance spectrum of the structured fabrics prepared in Example 1 and Comparative Example 3.

[0034] Figure 12 In the figures, a and b are the particle size distribution and zeta potential of the H-SiO2 nanospheres modified in Example 1 and Comparative Example 4, respectively; c and d are digital photographs and reflectance spectra of the structured fabrics prepared in Example 1 and Comparative Example 4.

[0035] Figure 13 In the image, a, b, c, and d are digital photographs of polyester, spandex, silk, and linen, respectively; e, f, g, and h are optical microscope images of polyester, spandex, silk, and linen, showing the surface roughness and weaving structure of different fabrics; i, j, k, and l are photographs of structured colored fabrics of polyester, spandex, silk, and linen after dyeing. Detailed Implementation

[0036] The technical solution of the present invention will be further explained and illustrated below through specific embodiments.

[0037] Example 1:

[0038] like Figure 1 As shown, the method for preparing the structurally colored fabric in this embodiment includes the following steps:

[0039] (1) Using polystyrene microspheres (PS) with good monodispersity (180–630 nm) as the core, and coating the surface of the microspheres with a silica shell, core-shell microspheres of different sizes (PS@SiO2) were obtained. The core-shell microspheres were then etched in a 0.2 g / mL sodium hydroxide solution to create pores, resulting in porous core-shell colloidal microspheres (PS@E-SiO2). The etching time was adjusted to 30 min to ensure the pore size was within the mesoporous range. Finally, the dried porous core-shell colloidal microspheres were ground into powder in a mortar, then placed in a ceramic boat and calcined in a muffle furnace at a heating rate of 3 °C / min for 3 h at 450 °C to remove organic polymers, thus preparing surface-roughened hollow silica H-SiO2 nanospheres. The specific preparation process of the above-mentioned surface-roughened hollow silica nanospheres is existing technology and will not be elaborated here.

[0040] (2) 1g of H-SiO2 nanospheres were dispersed in 45mL of deionized water, and then ammonia water (NH3·H2O) was added to adjust the pH value to 12. After uniform dispersion and ultrasonic treatment, the mixture was stirred at 95℃ for 10h. The product was then centrifuged and washed three times to finally obtain photonic nano pigment.

[0041] Figure 2 a is a schematic diagram of surface modification used to enhance long-range electrostatic repulsion between nanospheres in this embodiment. Figure 2 b shows a comparison of the orange photonic nano-pigment aqueous solution before and after modification. It was observed that the unmodified nanospheres completely settled to the bottom, while the modified nanospheres still maintained good dispersibility. Figure 2c and 2d represent the particle size distribution and zeta potential of the unmodified and modified H-SiO2 nanospheres in this embodiment, respectively. After modification, the zeta potential of the H-SiO2 nanospheres changed from -12.25mV to -34.76mV, while the corresponding polydispersity index (PDI) decreased from 0.418 to 0.096. This indicates that the modified H-SiO2 nanospheres have good dispersibility.

[0042] (3) Disperse 1g of photonic nano pigment in 1.5mL of deionized water, then add 0.15g of aqueous acrylic emulsion WA, 0.004g of tannic acid TA and 0.008g of carbon black, and obtain a photonic nano pigment dispersion by ultrasonic homogenization; wherein, the glass transition temperature of the aqueous acrylic emulsion is -10℃.

[0043] (4) The cotton fabric is completely immersed in the photon nano pigment dispersion, and gently stirred to ensure full wetting. The immersion time is 20s. After that, the fabric is dried in an oven at 60℃. After cooling to room temperature, a structural color fabric with saturated color on both sides is finally obtained.

[0044] During the drying process, the aqueous acrylic emulsion WA is heated above the glass transition temperature, causing it to melt and fill the gaps between the nano-pigments and the yarn. As the temperature decreases, the curing of WA firmly bonds the nano-pigments to the cotton fabric, thereby providing the main color fastness. In a synergistic effect, TA acts as a key intermediate molecule, forming a cross-linked network with other components, further improving the structural color stability. Figure 3 This is an illustration of adhesion enhancement in this embodiment. Specifically, TA utilizes abundant phenolic hydroxyl groups to form dense hydrogen bond crosslinking points with the carboxyl groups of WA and the oxygen anions on the surface of modified H-SiO2 nanospheres. At the same time, TA undergoes self-condensation to achieve the effect of improving the stability of structural color.

[0045] In this embodiment, H-SiO2 photonic nanopigments with particle sizes of 266nm, 310nm, 343nm, 370nm, 423nm, and 473nm are used to dye cotton fabrics. Figure 4 a represents six structural dyed fabrics of different colors obtained through a one-step dyeing method, namely, magenta, purple, blue, cyan, green, and orange structural dyed fabrics. Figure 4 b、 Figure 4 c represents the corresponding reflectance spectra of the front and back sides of the structural fabric in this embodiment, showing a uniform color on both sides with no obvious color difference. Figure 4 d represents digital photographs of green, blue, and magenta fabrics from different angles in this embodiment. Their colors were observed sequentially from different viewing angles (0°, 30°, 60°), and no significant color changes were observed. Figure 4e-4g are three-dimensional mapping projections of the reflectance spectra of green, blue, and purplish-red samples, independent of angle, respectively, with no significant change in the reflectance peaks.

[0046] Figure 5 a is a scanning electron microscope image of the white cotton fabric in this embodiment. It is observed that the cotton fabric is woven by specific warp and weft threads, resulting in a layered porous structure with large cracks between the yarns and a disordered, irregularly curled structure on the fabric surface. Figure 5 b is a structured fabric with H-SiO2 photonic nano-pigment attached. These nanospheres can be seen to be randomly distributed on the surface of the yarn, while effectively filling the gaps between cotton fibers under the drive of capillary action. Figure 5 c is a scanning electron microscope image of the H-SiO2 / WA-TA structured colored fabric bonded with WA-TA. After the introduction of WA-TA, no photonic nano-pigment and adhesive were found to cover the braiding holes between the yarns. The results show that the one-step dyeing method can achieve precise local coloring of photonic nano-pigment on the fabric, which is crucial for maintaining the breathability and softness of the structured colored fabric.

[0047] Figure 6 a, Figure 6 c represents digital photographs and reflectance spectral changes of H-SiO2 / WA / cotton fabrics with different WA contents before and after friction. Dispersions containing only photonic nano-pigments and WA at different concentrations (0-25 wt%) were prepared, and then structural color fabrics were prepared using a dyeing method. As the WA concentration increased, the structural color of the fabric gradually changed from a bright green to a deeper hue. When the WA concentration reached 25 wt%, the fabric almost turned black, and the reflectance peak almost disappeared. Figure 6 b、 Figure 6 Images d show digital photographs and reflectance spectral changes of H-SiO2 / WA-TA / cotton with different TA contents before and after washing. More rigorous washing tests were conducted on structural color fabrics with different TA contents (0wt%-0.8wt%). After washing with 0.3 vol% liquid detergent in 40°C water for 45 minutes, significant detachment of photonic nanoparticles was observed in the periphery and central areas of the fabric without TA. In contrast, the addition of only 0.2 wt% TA significantly inhibited the detachment of photonic nanoparticles. When the TA content increased to 0.4 wt% or higher, the structural color in the periphery and central areas of the fabric remained almost unchanged, and the corresponding reflectance spectral changes after washing confirmed these results.

[0048] Durability tests were conducted on the prepared structural dyed fabric. Figure 7 a, Figure 7 b and Figure 7c represents digital photographs and reflectance spectra of the H-SiO2 / cotton and H-SiO2 / WA-TA / cotton fabrics after durability tests, including 2 hours of water immersion, 50 brush washes, 45 minutes of washing, and 30 minutes of ultrasonic treatment. The structural color and reflectance spectra of both fabrics showed no significant changes after mild water immersion. After brush washing, the photonic nano-pigment on the H-SiO2 / cotton fabric was significantly detached, leading to a broadening of the reflectance peak, a decrease in intensity, and degradation of the structural color. After washing, the structural color on the H-SiO2 / cotton fabric completely faded, exposing the original white fabric. After ultrasonic treatment, the white substrate was completely exposed on the H-SiO2 / cotton fabric. However, the structural color and corresponding reflectance spectra of the H-SiO2 / WA-TA / cotton fabric remained intact after these tests. This indicates that the prepared structural color fabric possesses strong colorfastness. Figure 7 Image d is a digital photograph showing the softness of H-SiO2 / WA-TA / cotton fabric. After being repeatedly kneaded and unfolded 20 times, the H-SiO2 / WA-TA / cotton fabric can still return to its original state. Figure 7 e and Figure 7 f shows a schematic diagram of the continuous rotundation process and a digital photograph of the prepared structured colored fabric, including dye solution impregnation, heat drying, and fabric collection. The continuous rotundation process successfully demonstrates the industrial dyeing potential of photonic nano-pigments in double-sided structured colored fabrics.

[0049] The air permeability of the prepared structural dyed fabric was tested. Figure 8 To demonstrate the air permeability of the prepared structural dyed fabric, when the H-SiO2 / WA-TA / cotton fabric was placed between hot water and a dry glass slide, water vapor immediately passed through the sample and subsequently condensed on the glass, indicating the fabric's excellent air permeability.

[0050] Comparative Example 1:

[0051] The method for preparing the structural colored fabric in this comparative example differs from that in Example 1 in that:

[0052] Polydimethylsiloxane (PDMS) was used instead of the binder WA in Example 1 and dispersed in tetrahydrofuran, with other conditions consistent with Example 1;

[0053] Figure 9 In the image, a and b are digital photographs and reflectance spectra of two structural color fabrics prepared with WA and PDMS as binders, respectively. By comparison, it can be seen that when the binder is replaced with PDMS, the color of the structural color fabric is darker, the characteristic peaks are wider and the peak values ​​are lower. Figure 9In the images, c and d show digital photographs and reflectance spectra of two structural color fabrics after 20 rubs, respectively. When the adhesive was replaced with PDMS, the colorfastness of the fabric prepared with WA as the adhesive was significantly worse than that prepared with WA. After rubbing, the fabric color became noticeably lighter, and the reflectance peak further decreased, while the structural color fabric prepared with WA as the adhesive showed no color change. The reason for this significant difference is that the carboxyl groups in WA can form dense hydrogen bond crosslinking points with the abundant phenolic hydroxyl groups in TA, further improving the colorfastness of the structural color fabric; while PDMS itself does not have groups that can effectively form hydrogen bonds with phenolic hydroxyl groups, and therefore cannot provide sufficient force to ensure the structural colorfastness of the fabric when subjected to external friction.

[0054] Comparative Example 2:

[0055] The method for preparing the structural colored fabric in this comparative example differs from that in Example 1 in that:

[0056] PDMS modified with 2-formylphenylboronic acid (PBA) (PDMS-PBA) was used instead of the binder WA in Example 1 and dispersed in tetrahydrofuran, with other conditions consistent with Example 1.

[0057] The specific modification method is as follows: 0.04 g of PBA and 10 g of PDMS are dissolved in 120 mL of tetrahydrofuran and stirred overnight; then, 0.02 g of sodium borohydride is slowly added under vigorous stirring, and stirring is continued for 2 hours. Finally, the solvent is removed by distillation to obtain PDMS-PBA;

[0058] Figure 10 In the image, a and b are digital photographs and reflectance spectra of two structural color fabrics prepared with WA and PDMS-PBA as adhesives, respectively. By comparison, it can be seen that when the adhesive is replaced with PDMS-PBA, the color of the structural color fabric becomes significantly darker, the characteristic peaks become wider and the peak values ​​are very low. Figure 10 In the images, c and d represent digital photographs and reflectance spectra of two structural color fabrics after 20 rubs, respectively. The structural color fabric prepared using PDMS-PBA as a binder showed no significant change in color or spectrum after rubbing, as did the structural color fabric prepared using WA as a binder. However, the structural color fabric prepared using PDMS-PBA as a binder had a less vibrant color than the one prepared using WA. This significant difference is due to the fact that the introduction of PBA disrupted the relatively orderly molecular arrangement of PDMS, leading to a significant change in the refractive index of PDMS and affecting the color-generating properties of the photonic nano-pigment, resulting in a duller color.

[0059] Comparative Example 3:

[0060] The method for preparing the structural colored fabric in this comparative example differs from that in Example 1 in that:

[0061] The prepared H-SiO2 nanospheres were directly mixed with WA, carbon black, TA and water to prepare a photonic nano pigment solution without undergoing an alkaline modification step. Other conditions were the same as in Example 1.

[0062] Figure 11 In the image, a and b are digital photographs of structural color fabrics obtained by photonic nano-solution dyeing with modified and unmodified H-SiO2 nanospheres, respectively. By comparison, it can be seen that the structural color fabric obtained by photonic nano-solution dyeing with modified H-SiO2 nanospheres has a bright and uniform color, while the structural color fabric obtained by photonic nano-solution dyeing with unmodified H-SiO2 nanospheres has a significantly poor color uniformity, and localized accumulation of photonic nano-pigments can be clearly seen on the fabric surface. Figure 11 In the diagram, c represents the reflection spectra of the two structural fabrics. The structural fabric prepared by modifying H-SiO2 nanospheres exhibits a narrower characteristic peak and higher peak intensity in its reflection spectrum. The unmodified structural fabric, due to color differences, shows a wider characteristic peak and lower peak intensity. This significant difference arises because the unmodified H-SiO2 nanospheres have poor dispersibility in aqueous solution, readily agglomerating and precipitating. When the fabric is immersed in the solution, the agglomerated photonic nanoparticles accumulate locally on the fabric surface, resulting in uneven color. After modification, the dispersibility of the H-SiO2 nanospheres in aqueous solution is significantly improved, and the photonic nanoparticles are uniformly distributed on the fabric surface after dyeing, resulting in a uniform color.

[0063] Comparative Example 4:

[0064] The method for preparing the structural colored fabric in this comparative example differs from that in Example 1 in that:

[0065] 1g of the prepared H-SiO2 nanospheres were dispersed in 45mL of deionized water without adding alkali to adjust the pH of the solution. After uniform dispersion and ultrasonic treatment, the mixture was stirred at 95℃ for 10h. Subsequently, the product was centrifuged and washed three times to finally obtain the photonic nano pigment. Other conditions were the same as in Example 1.

[0066] Figure 12Figures a and b show the particle size distribution and zeta potential of H-SiO2 nanospheres modified with and without alkali, respectively. Compared with H-SiO2 nanospheres modified with alkali, the zeta potential of H-SiO2 nanospheres modified directly with aqueous solution without alkali changed from -34.76 mV to -21.13 mV, while the corresponding polydispersity index (PDI) increased from 0.096 to 0.201. This indicates that the dispersibility of H-SiO2 nanospheres obtained by adjusting the pH of the solution without adding alkali will be worse. Figure 12 c and d are digital photographs and reflection spectra of structural colored fabrics obtained by further preparing photonic nano-pigment solutions from H-SiO2 nanospheres modified with and without alkali, respectively. The comparison shows that the color uniformity of the structural colored fabrics obtained by adding alkali is improved.

[0067] Example 2:

[0068] The structural colored fabric in this embodiment differs from that in Embodiment 1 in that:

[0069] Polyester, spandex, silk, and linen were used instead of the cotton fabric in Example 1 for coloring, while other conditions were the same as in Example 1.

[0070] Figure 13 ad are digital photos of polyester, spandex, silk, and linen, respectively. Figure 13 Eh represents optical microscope images of polyester, spandex, silk, and linen, showing their different surface roughness and weave structures. Figure 13 The images show photographs of structured color fabrics after dyeing polyester, spandex, silk, and linen, respectively. It was observed that the photonic nano-pigments can adhere well to various fibers, exhibiting bright and uniform structured colors on both sides of these fabrics. This indicates that the photonic nano-pigments provide excellent coverage on various fabrics and are not limited by the fabric material or surface properties during the dyeing process.

[0071] Example 3:

[0072] The structural colored fabric in this embodiment differs from that in Embodiment 1 in that:

[0073] Hollow nanospheres with rough surfaces, such as titanium dioxide, zirconium dioxide, tin dioxide, cerium dioxide, zinc oxide, copper oxide, and zinc sulfide, were used instead of the hollow SiO2 nanospheres in Example 1 as photonic nanopigments for coloring fabrics. Other conditions were the same as in Example 1.

[0074] Example 4:

[0075] The structural colored fabric in this embodiment differs from that in Embodiment 1 in that:

[0076] Sodium carbonate, sodium bicarbonate, sodium hydroxide, and ammonium bicarbonate solutions were used instead of the ammonia solution in Example 1 as the alkaline solution to modify the photonic nano pigments, while other conditions were the same as in Example 1.

[0077] The breathable and durable structural dyed fabric prepared by the above embodiments of the present invention can be applied to green printing and dyeing and smart fabrics.

[0078] This invention uses rough-surfaced hollow nanospheres as structural color materials and modifies the nanospheres with an alkaline solution to obtain photonic nanopigments. Leveraging the assembly-free and single-sphere color-generating characteristics of photonic nanopigments, a simple and efficient one-step dyeing strategy is developed to prepare double-sided structurally colored fabrics with high saturation, good color fastness, inherent softness, and excellent breathability. This simple dyeing mechanism can be widely adapted to fabrics with different surface roughness and weave structures and has great potential for large-scale dyeing. This dyeing strategy opens a practical avenue for industrial dyeing of fabrics using nanoscale structural color units.

[0079] Given that there are numerous embodiments of the present invention, and the raw materials and quantities involved can be selected within a limited range according to actual needs, and that the experimental data for each embodiment are extensive and numerous, it is not suitable to list and describe them one by one here. However, the content to be verified and the final conclusions obtained in each embodiment are similar. Therefore, the verification content of each embodiment will not be described one by one here.

[0080] The above description is merely a detailed explanation of preferred embodiments and principles of the present invention. For those skilled in the art, there may be changes in specific implementation methods based on the ideas provided by the present invention, and these changes should also be considered within the scope of protection of the present invention.

Claims

1. A method for producing a structural color fabric, characterized by, The method comprises the following steps: (1) dispersing the hollow nanospheres with rough surface in an aqueous solution, and adding an alkali solution to modify the hollow nanospheres to obtain photonic nano pigments; wherein the hollow nanospheres are hollow silica, titanium dioxide, zirconium dioxide, tin dioxide, cerium dioxide, zinc oxide, copper oxide or zinc sulfide; (2) preparing a photonic nano pigment solution by mixing the photonic nano pigments, an aqueous acrylic emulsion, carbon black, tannic acid and water; (3) immersing the fabric in the photonic nano pigment solution, and then placing the fabric in an oven for heat treatment to obtain a structural color fabric.

2. The production method according to claim 1, characterized by, In the step (2), the mass fraction of the photonic nano pigments in the photonic nano pigment solution is 20-30 wt%, the mass fraction of the aqueous acrylic emulsion is 10-20 wt%, the mass fraction of the carbon black is 0.1-0.5 wt%, the mass fraction of the tannic acid is 0.1-0.8 wt%, and the rest is water.

3. The production method according to claim 1, characterized by, In the step (3), the fabric is immersed for 5-60 s, and the heat treatment temperature of the oven is 50-90℃.

4. The production method according to any one of claims 1 to 3, characterized by, In the step (1), the pH of the solution is adjusted to 10-12 by the alkali solution.

5. The method of any one of claims 1-3, wherein the method further comprises, In the step (1), the alkali solution is a sodium carbonate solution, a sodium bicarbonate solution, an ammonia water solution or an ammonium bicarbonate solution.

6. The method of any one of claims 1-3, wherein, In the step (1), the modified solution is stirred at 80-95℃ after the addition of the alkali solution.

7. The method of any one of claims 1-3, wherein, The fabric substrate is cotton, polyester, polyester-cotton, polyester-ammonia, wool-polyester, polyester-viscose or polyester-cotton.

8. The structured color fabric prepared according to the preparation method of any one of claims 1-7, wherein, The structural color fabric has a double-sided structural color.

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