Alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene compound and application of alternating electrostatic layer-by-layer assembly gradient hair dyeing method

Abstract

The invention discloses an alternate electrostatic layer-by-layer assembly gradient hair dyeing method based on an MXene compound and application thereof, the hair dyeing method comprises the following steps: S1, spraying a chitosan solution on the surface of hair so that the chitosan solution wraps the hair, and naturally permeating; s2, spraying the Ti < 3 > C < 2 > T < x > at gallic acid compound on the surface of the hair, so that the Ti < 3 > C < 2 > T < x > at gallic acid compound wraps the hair; s3, alternately spraying the chitosan solution and the Ti3C2Tx at gallic acid compound on the surface of the hair, so that the chitosan solution and the Ti3C2Tx at gallic acid compound alternately wrap the hair to form at least five gradient composite layers; the Ti < 3 > C < 2 > T < x > at gallic acid compound is formed by connecting Ti < 3 > C < 2 > T < x > and gallic acid through a C-O-Ti coordinate bond; according to the hair dyeing method, the efficient and lasting dyeing effect is achieved, the smoothness of the hair surface can be remarkably improved, and the mechanical property of the hair is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of hair dyes, and particularly relates to an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composites and its applications. Background Art

[0002] With the upgrading of consumers' demands for the safety, functionality and environmental friendliness of personal care products, traditional hair dyes are facing three major technical challenges: chemical toxicity risks, single functionality, and low material efficiency. Commercially available chemical hair dyes generally contain ammonia (concentration 4 - 6%), hydrogen peroxide (6 - 12%) and aniline dyes (such as p-phenylenediamine, PPD content 1 - 3%). Long-term use results in a scalp irritation rate as high as 12 - 15%, and PPD has been listed as a restricted substance by the European Union. More seriously, the formaldehyde concentration released during the hair dyeing process can reach 200 - 500 ppm, far exceeding the WHO safety threshold (<0.1 ppm). In terms of functionality, traditional products only focus on the dyeing effect and lack additional functions such as UV protection and antistatic properties, unable to meet the needs of modern consumers for multi-functional care.

[0003] In recent years, two-dimensional transition metal carbides (MXene) have provided new ideas for the innovation of hair dyes due to the modifiable groups (-O / -OH / -F end groups) on their surfaces and broadband light absorption (400 - 800 nm) characteristics. The Ti3C2T x (MXene) / collagen composite hair dye developed by the Hwang team in South Korea, although achieving the electromagnetic shielding function (5.1 dB), has key defects: the MXene loading needs to be ≥1 wt% to ensure uniform dyeing, and the mechanical enhancement effect is limited (the yield strength is only increased by 11.25%); moreover, MXene causes a 42% increase in the surface friction coefficient of hair, which is directly related to the topological reconstruction induced by the van der Waals force between MXene sheets.

[0004] CN 118615172 A discloses a preparation method and a dyeing method of a Ti3C2T x hair dye, and CN118615173 A discloses the application of Ti3C2T x in hair dyes. The hair dyeing methods of these two inventions are both: by adding Ti3C2T capped with amino or carboxyl functional groups to the mixed base solution of chitosan and gallic acid, x and then preparing the hair dye, and then spraying the hair dye on the hair, evenly applying, combing, and drying to achieve hair dyeing. However, the hair dyeing methods of these two inventions both have the following defects: (1) Ti3C2T in the hair dye xThe lamellae are uncontrollably stacked due to van der Waals and hydrogen bond interactions, easily forming μm-sized aggregates, which affects the hair dyeing effect; (2) By repeating single spraying to form disordered stacking, the hair surface is rough. Summary of the Invention

[0005] In view of the above deficiencies in the prior art, an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite is provided. This hair dyeing method not only achieves an efficient and long-lasting dyeing effect, but also has excellent wash-fastness, can significantly improve the smoothness of the hair surface, effectively enhance the mechanical properties of the hair, and at the same time has excellent photothermal conversion and thermal management effects, as well as significantly improved antistatic performance and other multiple significant advantages.

[0006] The purpose of the present invention is to provide an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite, including the following steps: S1. Spraying a chitosan solution on the surface of the hair strands so that the chitosan solution wraps the hair strands and naturally penetrates; S2. Then spraying the Ti3C2T x @gallic acid composite on the surface of the hair strands so that the Ti3C2T x @gallic acid composite wraps the hair strands; S3. Then alternately spraying the chitosan solution and the Ti3C2T x @gallic acid composite on the surface of the hair strands so that the chitosan solution and the Ti3C2T x @gallic acid composite alternately wrap the hair strands to form a gradient composite layer with at least 5 layers; The Ti3C2T x @gallic acid composite is formed by connecting Ti3C2T x and gallic acid through C-O-Ti coordination bonds.

[0007] In the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite of the present invention, due to the inherent negative charge characteristics of the hair surface (isoelectric point pH≈3.67), positively charged amino protonated chitosan (ζ=+37.9 mV) first forms a dense base film on the hair surface through electrostatic attraction; subsequently, gallic acid coordinates with the surface Ti atoms of Ti3C2T x through phenolic hydroxyl groups, reducing the ζ potential to -35.5 mV. A potential difference of up to 73.4 mV (corrected value) is generated between the negatively charged Ti3C2T x @gallic acid composite and the chitosan layer, driving the two to form a gradient structure composite film through strong electrostatic self-assembly, and achieving a gradient composite layer with uniform coverage of ≥5 layers through an alternating spraying process.

[0008] In some embodiments of the present invention, in S1, the mass concentration of the chitosan solution is 0.1-0.5%.

[0009] In some embodiments of the present invention, in S1, the pH value of the chitosan solution is 5.0 - 6.0.

[0010] In some embodiments of the present invention, in S1, the chitosan solution further contains an antioxidant.

[0011] In some embodiments of the present invention, in S2, the interlayer spacing of the Ti3C2T x @gallic acid complex is 1.05 nm.

[0012] In some embodiments of the present invention, in S2, the 002 crystal plane characteristic peak of the Ti3C2T x @gallic acid complex is shown at 2θ = 6.06° ± 0.1°.

[0013] In some embodiments of the present invention, after the chitosan solution is sprayed on the hair surface or the Ti3C2T x @gallic acid complex is sprayed on the hair surface, a drying operation is further performed.

[0014] In some embodiments of the present invention, the preparation method of the Ti3C2T x @gallic acid complex includes the following steps: Mix the Ti3C2T x solution with the gallic acid solution to obtain the Ti3C2T x @gallic acid complex.

[0015] In some embodiments of the present invention, the mass concentration of the Ti3C2T x solution is 0.05 - 0.25%.

[0016] In some embodiments of the present invention, the mass concentration of the gallic acid solution is 0.1 - 0.5%.

[0017] In some embodiments of the present invention, the mass ratio of the Ti3C2T x to gallic acid is 1:0.8 - 1:5.

[0018] In some embodiments of the present invention, the surface of the Ti3C2T x at least contains hydroxyl groups.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene complex of the present invention can achieve high-efficiency dyeing at low concentration, with a small dosage of Ti3C2T x , and the Ti3C2T x in the Ti3C2T xThe mass concentration as low as 0.05% can achieve an 80% decrease in hair brightness and a color retention rate of >95% after 20 washes. Compared with the Ti3C2T x system of CN118615172A, the material consumption is reduced by 10-20 times.

[0020] (2) The mechanical properties of the hair treated by the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite of the present invention are strengthened, the yield strength is increased by 32.5%, and the yield strength of the hair is increased from 87.174 MPa to 115.520 MPa; the tensile strength is increased by 14.4%, and the yield strength of the hair is increased from 188.196 MPa to 215.384 MPa.

[0021] (3) The surface of the hair treated by the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite of the present invention is smooth and almost consistent with the roughness of the untreated hair. In addition, the hair treated by the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite of the present invention also exhibits excellent ultraviolet protection and antistatic properties. Description of the Drawings

[0022] Figure 1 Fourier transform infrared spectrum of Ti3C2Tx prepared in Example 1.

[0023] Figure 2 Ultraviolet-visible absorption spectrum of Ti3C2Tx prepared in Example 1.

[0024] Figure 3 Comparison diagram of X-ray diffraction patterns of Ti3C2Tx prepared in Example 1 and Ti3C2Tx@gallic acid composite prepared in Example 5.

[0025] Figure 4 For Ti3C2T prepared in Example 1 x And Ti3C2T prepared in Example 5 x @Gallic acid composite scanning electron microscope images: a) Surface morphology (lateral size 1-4.6 μm); b) Edge layered structure; c) Cross-section stacking state.

[0026] Figure 5 For gallic acid solution, Ti3C2T x dispersions, chitosan solutions and Ti3C2T x @Gallic acid composite zeta potential diagrams prepared in Examples 1-3 and 5.

[0027] Figure 6 Comparison diagram of hair dyeing effects of hair before hair dyeing treatment and hair treated in Examples 9-13.

[0028] Figure 7 It is a brightness analysis diagram of the hair before hair dyeing treatment and the hair after hair dyeing in Examples 9 to 13, Comparative Examples 2 to 5, and Comparative Examples 6 to 10.

[0029] Figure 8 It is a comparison diagram of SEM images of the treated hair in Example 10 and Comparative Example 1.

[0030] Figure 9 It is a wash resistance test diagram of the hair before hair dyeing treatment and the hair treated with Examples 9 to 13.

[0031] Figure 10 It is an average brightness change diagram of the hair before hair dyeing treatment and the hair treated with Examples 9 to 13.

[0032] Figure 11 It is a stress-strain curve diagram of the hair before hair dyeing treatment and the hair treated with Example 10.

[0033] Figure 12 It is the thermal management performance of the hair before hair dyeing treatment and the hair treated with Example 10: a) The temperature rise is 2.3 °C under 300 W xenon lamp illumination for 10 s; b) The temperature drops by 1.6 °C 10 s after stopping illumination.

[0034] Figure 13 It is an antistatic performance test diagram of the hair before hair dyeing treatment and the hair treated with Example 10. Detailed implementation manners

[0035] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] uncoated represents the hair before hair dyeing treatment.

[0037] Example 1 This example provides the preparation of Ti3C2T x Specifically, it includes the following steps: After stirring 1 g of lithium fluoride with 40 mL of 9 M hydrochloric acid in a polytetrafluoroethylene beaker for 30 min, 1 g of Ti3AlC2 powder was slowly added to the polytetrafluoroethylene beaker, and then the reaction was carried out at 40 °C for 24 hours. After the reaction, the reaction solution was centrifuged (3500 rpm, 5 min), and the supernatant was discarded. Then, it was washed several times with deionized water until the pH value of the supernatant was about 6. An appropriate amount of deionized water was added to the precipitate, and it was ultrasonically treated in an ice-water bath under a nitrogen atmosphere for 10 - 20 min. Finally, it was centrifuged again (3500 rpm, 10 min), and the upper-layer dispersion was collected to obtain Ti3C2T x dispersion.

[0038] The Ti3C2T prepared in this example x has an FTIR as Figure 1 shown. An absorption peak at 3509 cm -1 was observed, which is attributed to the stretching vibration of -OH, and a peak at 1655 cm -1 corresponding to the stretching vibration of C=O. The presence of these characteristic peaks is highly consistent with the previously reported Ti3C2T x data, strongly confirming the successful synthesis of Ti3C2T in this example x and the enrichment of the expected functional groups on its surface.

[0039] The UV-Vis spectrum of the Ti3C2T prepared in this example x is as Figure 2 shown. In the ultraviolet wavelength range of 200 - 400 nm, Ti3C2T x exhibits strong absorption characteristics, indicating that Ti3C2T x has excellent ultraviolet absorption ability. By calculation, when the mass fraction of Ti3C2T x is 0.05 wt%, the composite film has an ultraviolet absorption rate of >99.9% for ultraviolet light with a wavelength of 200 - 400 nm.

[0040] Example 2 This example provides the preparation of a gallic acid solution, which specifically includes the following steps: Add 40 mg of gallic acid to a glass bottle and add 10 ml of distilled water. Through 30 min of ultrasonic treatment (ultrasonic temperature 40 °C, ultrasonic power 180 W), the gallic acid is completely dissolved to obtain a 4 mg / ml gallic acid solution.

[0041] Example 3 This example provides the preparation of a chitosan solution, which specifically includes the following steps: Take 20 mg of L-ascorbic acid and add it to a 20 mL glass bottle. Inject 10 mL of distilled water and use an ultrasonic disperser to ultrasonically treat the solution for 10 min to dissolve the L-ascorbic acid. Subsequently, add 20 mg of chitosan to the solution and continue ultrasonically treating for 30 min to dissolve the chitosan, obtaining a chitosan solution with a pH value of 5.0 - 6.0.

[0042] Example 4 This example provides the preparation of the Ti3C2T x @gallic acid complex, which specifically includes the following steps: Take 10 mg of Ti3C2T x and add it to a 20 mL glass bottle. Inject 10 mL of deionized water and use a vortex mixer to vortex and mix for 1 min to prepare a 1 mg / ml Ti3C2T x solution. Subsequently, add 10 ml of a 4 mg / ml gallic acid solution, and vortex and mix the mixed solution for 30 s to obtain a stable Ti3C2T x @gallic acid. In the Ti3C2T x @gallic acid, the mass concentration of Ti3C2T x is 0.05%.

[0043] Example 5 This example provides the preparation of the Ti3C2T x @gallic acid complex. The difference from Example 4 is only that 10 mg of Ti3C2T x is replaced with 20 mg of Ti3C2T x , and it specifically includes the following steps: Take 20 mg of Ti3C2T x and add it to a 20 mL glass bottle. Inject 10 mL of deionized water and use a vortex mixer to vortex and mix for 1 min to prepare a 2 mg / ml Ti3C2T x solution. Subsequently, add 10 ml of a 4 mg / ml gallic acid solution, and vortex and mix the mixed solution for 30 s to obtain a stable Ti3C2T x @gallic acid. In the Ti3C2T x @gallic acid, the mass concentration of Ti3C2T x is 0.1%.

[0044] It can be seen from Figure 3 that the characteristic peak (002) of the Ti3C2T prepared in Example 1 is located at 6.06°, and the characteristic peak of Ti3C2T x can confirm the Ti3C2T x and xThe typical crystal phase effectively excludes the possibility of residual MAX phase or other impurities during the synthesis process, ensuring the purity of the material. For the Ti3C2T prepared in Example 5 x The characteristic peak (002) of @gallic acid is located at 6.26 o , and through the calculation of the Bragg equation, the d-spacing of the crystal plane of Ti3C2T x @gallic acid is 0.048 nm less than that of pure Ti3C2T x , which proves that the addition of gallic acid makes Ti3C2T x nanosheets become ordered and dense during the stacking process.

[0045] From Figure 4 it can be seen that Ti3C2T x has a two-dimensional layered structure, and the lateral size of a single sheet is approximately in the range of 1 - 4.6 μm. This morphological characteristic helps its uniform distribution on the hair surface.

[0046] From Figure 5 it can be seen that the zeta potentials of the gallic acid solution, Ti3C2T x dispersion, Ti3C2T x @gallic acid complex, and chitosan solution prepared in Examples 1 - 4 are -20.9 mV, -40.31 mV, -35.5 mV, and +37.9 mV respectively. Due to the inherent negative charge characteristic of the hair surface (isoelectric point pH≈3.67), positively charged amino protonated chitosan (ζ = +37.9 mV) first forms a dense basal membrane on the hair surface through electrostatic attraction; subsequently, the negatively charged Ti3C2T x @gallic acid complex (ζ = -35.5 mV) and the chitosan layer have a potential difference of up to 73.4 mV (corrected value), driving the two to form a gradient structure composite film through strong electrostatic self-assembly, and achieving a gradient composite layer with ≥5 layers of uniform coverage through an alternating spraying process.

[0047] Example 6 This example provides the preparation of Ti3C2T x @gallic acid complex. The difference from Example 4 is only that 10 mg of Ti3C2T x is replaced with 30 mg of Ti3C2T x , and the specific steps are as follows: Take 30 mg of Ti3C2T x and add it to a 20 mL glass bottle, inject 10 mL of deionized water, and use a vortex mixer to mix evenly for 1 min to obtain 3 mg / ml Ti3C2T xSolution. Subsequently, 10 mL of 4 mg / mL gallic acid solution was added, and the mixed solution was vortexed for 30 s to obtain a stable Ti3C2T x @gallic acid, in Ti3C2T x @gallic acid, the mass concentration of Ti3C2T x was 0.15%.

[0048] Example 7 This example provides the preparation of the Ti3C2T x @gallic acid complex, which is only different from Example 4 in that 10 mg of Ti3C2T x was replaced with 40 mg of Ti3C2T x , and the specific steps are as follows: Take 40 mg of Ti3C2T x and add it to a 20 mL glass bottle, inject 10 mL of deionized water, and vortex for 1 min using a vortex mixer to obtain a 4 mg / mL Ti3C2T x solution. Subsequently, 10 mL of 4 mg / mL gallic acid solution was added, and the mixed solution was vortexed for 30 s to obtain a stable Ti3C2T x @gallic acid, in Ti3C2T x @gallic acid, the mass concentration of Ti3C2T x was 0.2%.

[0049] Example 8 This example provides the preparation of the Ti3C2T x @gallic acid complex, which is only different from Example 4 in that 10 mg of Ti3C2T x was replaced with 50 mg of Ti3C2T x , and the specific steps are as follows: Take 50 mg of Ti3C2T x and add it to a 20 mL glass bottle, inject 10 mL of deionized water, and vortex for 1 min using a vortex mixer to obtain a 5 mg / mL Ti3C2T x solution. Subsequently, 10 mL of 4 mg / mL gallic acid solution was added, and the mixed solution was vortexed for 30 s to obtain a stable Ti3C2T x @gallic acid, in Ti3C2T x @gallic acid, the mass concentration of Ti3C2T x was 0.25%.

[0050] Example 9 This embodiment provides an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite, which specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 into a 20 mL spray bottle, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is carefully wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. Immediately afterwards, inject the Ti3C2T x @ gallic acid with a mass concentration of 0.05% prepared in Example 4 into another spray bottle, and repeat the above processes of spraying, combing and drying; S3. Steps S1 and S2 are alternately executed. During the whole process, the chitosan solution is sprayed three times, while the Ti3C2T x @ gallic acid is sprayed twice to form a 5-layer gradient composite layer.

[0051] Example 10 This embodiment provides an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite. The difference from Example 9 is only that the "Ti3C2T x @ gallic acid with a mass concentration of 0.05% prepared in Example 4" in Example 9 is replaced with "Ti3C2T x @ gallic acid with a mass concentration of 0.1% prepared in Example 5", and specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 into a 20 mL spray bottle, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is carefully wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. Immediately afterwards, inject the Ti3C2T x @ gallic acid with a mass concentration of 0.1% prepared in Example 5 into another spray bottle, and repeat the above processes of spraying, combing and drying; S3. Steps S1 and S2 are alternately executed. During the whole process, the chitosan solution is sprayed three times, while the Ti3C2T x @ gallic acid is sprayed twice to form a 5-layer gradient composite layer.

[0052] Example 11 This embodiment provides an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite. The difference from Example 9 is only that the "Ti3C2T x @ gallic acid with a mass concentration of 0.05% prepared in Example 4" in Example 9 is replaced with "Ti3C2T x @ gallic acid with a mass concentration of 0.15% prepared in Example 6", and specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 into a 20 mL spray bottle, and then gently and evenly spray it on the surface of the hair strands, ensuring that each hair strand is carefully wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. Immediately afterwards, inject the Ti3C2T x @gallic acid with a mass concentration of 0.15% prepared in Example 6 into another spray bottle, and repeat the above processes of spraying, combing, and drying; S3. Alternately execute Steps S1 and S2. During the whole process, the chitosan solution is sprayed three times, while the Ti3C2T x @gallic acid is sprayed twice to form a 5-layer gradient composite layer.

[0053] Example 12 This example provides an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite. The difference from Example 9 is only that the "Ti3C2T x @gallic acid with a mass concentration of 0.05% prepared in Example 4" in Example 9 is replaced with "Ti3C2T x @gallic acid with a mass concentration of 0.2% prepared in Example 7", and the specific steps are as follows: S1. Slowly inject the chitosan solution prepared in Example 3 into a 20 mL spray bottle, and then gently and evenly spray it on the surface of the hair strands, ensuring that each hair strand is carefully wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. Immediately afterwards, inject the Ti3C2T x @gallic acid with a mass concentration of 0.2% prepared in Example 7 into another spray bottle, and repeat the above processes of spraying, combing, and drying; S3. Alternately execute Steps S1 and S2. During the whole process, the chitosan solution is sprayed three times, while the Ti3C2T x @gallic acid is sprayed twice to form a 5-layer gradient composite layer.

[0054] Example 13 This example provides an alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite. The difference from Example 9 is only that the "Ti3C2T x @gallic acid with a mass concentration of 0.05% prepared in Example 4" in Example 9 is replaced with "Ti3C2T x @gallic acid with a mass concentration of 0.25% prepared in Example 8", and the specific steps are as follows: S1. Slowly inject the chitosan solution prepared in Example 3 into a 20 mL spray bottle, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is finely wrapped. After natural penetration, perform careful combing and send it into a dryer for drying and shaping; S2. Immediately afterwards, inject the Ti3C2T x @gallic acid with a mass concentration of 0.25% prepared in Example 8 into another spray bottle, and repeat the above processes of spraying, combing and drying; S3. Alternately execute the two steps of S1 and S2. During the whole process, the chitosan solution is sprayed three times, while the Ti3C2T x @gallic acid is sprayed twice to form a 5-layer gradient composite layer.

[0055] As Figure 6 can be seen, by using the alternate electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite in Example 9, when the mass concentration of Ti3C2T x in the Ti3C2T x @gallic acid is 0.05 wt%, the hair color is also successfully changed to a dark black tone, demonstrating excellent coloring effect.

[0056] Comparative Example 1 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 into a 20 mL spray bottle, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is finely wrapped. After natural penetration, perform careful combing and send it into a dryer for drying and shaping; S2. Immediately afterwards, inject the Ti3C2T x @gallic acid with a mass concentration of 0.1% prepared in Example 5 into another spray bottle, and repeat the above processes of spraying, combing and drying; S3. Alternately execute the two steps of S1 and S2. During the whole process, the chitosan solution is sprayed twice, and the Ti3C2T x @gallic acid is sprayed twice to form a 4-layer gradient composite layer.

[0057] Comparative Example 2 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Prepare the Ti3C2T x dispersion liquid with a mass concentration of 0.1%, and mix the chitosan solution prepared in Example 3 and the Ti3C2T xSlowly pour into a 20 mL spray bottle, mix well, then gently and evenly spray it on the surface of the hair strands, ensuring that each hair strand is finely coated. After allowing it to naturally penetrate, comb it carefully and send it into a dryer to dry and set the style; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0058] Comparative Example 3 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Prepare the Ti3C2T dispersion prepared in Example 1 to a mass concentration of 0.2%, and combine the chitosan solution prepared in Example 3 and the Ti3C2T x dispersion with a mass concentration of 0.2% x Slowly pour into a 20 mL spray bottle, mix well, then gently and evenly spray it on the surface of the hair strands, ensuring that each hair strand is finely coated. After allowing it to naturally penetrate, comb it carefully and send it into a dryer to dry and set the style; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0059] Comparative Example 4 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Prepare the Ti3C2T dispersion prepared in Example 1 to a mass concentration of 0.5%, and combine the chitosan solution prepared in Example 3 and the Ti3C2T x dispersion with a mass concentration of 0.5% x Slowly pour into a 20 mL spray bottle, mix well, then gently and evenly spray it on the surface of the hair strands, ensuring that each hair strand is finely coated. After allowing it to naturally penetrate, comb it carefully and send it into a dryer to dry and set the style; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0060] Comparative Example 5 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Prepare the Ti3C2T dispersion prepared in Example 1 to a mass concentration of 1%, and combine the chitosan solution prepared in Example 3 and the Ti3C2T x dispersion with a mass concentration of 1% x Slowly pour into a 20 mL spray bottle, mix well, then gently and evenly spray it on the surface of the hair strands, ensuring that each hair strand is finely coated. After allowing it to naturally penetrate, comb it carefully and send it into a dryer to dry and set the style; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0061] Comparative Example 6 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 and the Ti3C2T x @ gallic acid with a mass concentration of 0.05% prepared in Example 4 into a 20 mL spray bottle, mix well, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is finely wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0062] Comparative Example 7 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 and the Ti3C2T x @ gallic acid with a mass concentration of 0.1% prepared in Example 5 into a 20 mL spray bottle, mix well, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is finely wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0063] Comparative Example 8 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 and the Ti3C2T x @ gallic acid with a mass concentration of 0.15% prepared in Example 6 into a 20 mL spray bottle, mix well, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is finely wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0064] Comparative Example 9 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 and the Ti3C2T x @ gallic acid with a mass concentration of 0.2% prepared in Example 7 into a 20 mL spray bottle, mix well, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is finely wrapped. After natural penetration, conduct meticulous combing and send it into a dryer for drying and shaping; S2. During the entire process of Step S1, repeat 5 times to form 5 composite layers.

[0065] Comparative Example 10 This comparative example provides a hair dyeing method, which specifically includes the following steps: S1. Slowly inject the chitosan solution prepared in Example 3 and the Ti3C2T x @gallic acid with a mass concentration of 0.25% prepared in Example 8 into a 20 mL spray bottle, mix well, and then gently and evenly spray it on the surface of the hair strands to ensure that each hair strand is finely wrapped. After natural penetration, perform careful combing and send it into a dryer for drying and shaping; S2. During the whole process of Step S1, repeat 5 times to form 5 composite layers.

[0066] As Figure 7 shown, to further quantify the color change after hair dyeing, the Adobe Photoshop software was used to objectively measure the hair brightness after treatment with different mass concentrations of Ti3C2T x @gallic acid in Examples 9 - 13. The results are as x shown in Figure 7 a. After treatment with different mass concentrations (0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%) of Ti3C2T x @gallic acid in Examples 9 - 13, the average brightness of the hair decreased significantly by more than 80%. This indicates that the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite of the present invention has significant coloring efficiency and color adhesion ability. To further verify the superiority of the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite of the present invention, through image analysis of the post-dyeing effects of Comparative Examples 2 - 5 and Comparative Examples 6 - 10 using the Adobe Photoshop software, it was found that the Ti3C2T x @gallic acid hair dye (Comparative Examples 6 - 10) containing gallic acid can significantly reduce the hair brightness value by more than 21% compared to the Ti3C2T x formulation without gallic acid (Comparative Examples 2 - 5). Further comparative studies showed that under the same formulation system, the new hair dyeing process adopted in Examples 9 - 13 can produce a more significant brightness regulation effect than the traditional hair dyeing method in Comparative Examples 6 - 10. The specific quantitative data can be seen in x the chromaticity analysis results of Figure 7 a and 7c. Among them, the parallel experiments of Example 10 and Comparative Example 6 showed that the optimized hair dyeing method can increase the brightness reduction amplitude by 27%. It is particularly worth noting that the hair dyeing effect of Example 1 of the present invention is close to that of Comparative Example 5, while Ti3C2T xThe mass concentration decreased by 10 times. These data not only prove that the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite of the present invention can still achieve efficient dyeing effect at low concentration, but also highlight that it has lower material consumption and better dyeing performance compared with the prior art. The present invention not only reduces the production cost, but also maintains excellent dyeing effect.

[0067] As Figure 8 shown, 8a is the SEM image of the hair before hair dyeing, 8b is the SEM image of the hair dyed by the hair dyeing method of Comparative Example 1, and 8c is the SEM image of the hair dyed by the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite of Example 10. The results show that: (1) Before hair dyeing: The surface of the original hair presents a natural smooth state (see Figure 8 a); (2) After being treated by the hair dyeing method of Comparative Example 1, a uniform coating is formed on the hair surface (see Figure 8 b), but compared with the original hair before hair dyeing, using the hair dyeing method of Comparative Example 1 increases the surface roughness of the hair. The main reason is that the Ti3C2T x nanosheets are physically stacked through van der Waals forces and hydrogen bonds of edge functional groups (-OH / -F) between the nanosheets, and the charge orientation arrangement has not been completed, resulting in random distribution of the sheet orientation; (3) Using the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite of Example 10: When the chitosan solution is sprayed on the outermost layer (see Figure 8 c), the SEM image shows that the surface roughness of the hair is significantly reduced and almost returns to the smoothness before hair dyeing. It can be seen that spraying the chitosan solution on the outermost layer can keep the hair after hair dyeing close to the original smoothness.

[0068] As Figure 9 shown, the hair dyeing durability of the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite of Examples 9-13 was evaluated. The specific method is as follows: The dyed hair samples were completely immersed in a 50 mL conical flask containing 40 mL of 5% (v / v) shampoo, vortex-mixed for 30 s each time, and then rinsed with water and dried. This process was repeated 20 times to simulate the hair dyeing persistence under long-term washing and care conditions. After multiple washings, the hair still remained its original black color, indicating that the hair dyed with gallic acid has excellent wash fastness.

[0069] As Figure 10 shown, to further quantitatively analyze the hair dyeing durability, the brightness change was evaluated by comparing the average RGB values of the hair samples before and after shampooing. The average brightness of the hair samples obtained by the hair dyeing method using the hair dyes of Examples 9-13 after 20 times of shampooing was calculated. The tiny brightness change amplitude proves that using Ti3C2T xThe excellent wash resistance of hair dyed by the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite with different mass concentrations of Ti3C2T in gallic acid. x As shown in and

[0070] , after treating the hair with the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite in Example 10 with reference to the test standard ISO 5079:2020, the yield strength of the hair increased from 87.174 MPa to 115.520 MPa (an increase of 32.52%), and the tensile strength increased from 188.196 MPa to 215.384 MPa (an increase of 14.45%).

[0070] As Figure 11 shown, after treating the hair with the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite in Example 10 with reference to the test standard ISO 5079:2020, the yield strength of the hair increased from 87.174 MPa to 115.520 MPa (an increase of 32.52%), and the tensile strength increased from 188.196 MPa to 215.384 MPa (an increase of 14.45%). As Figure 12 shown, the thermal responses of untreated hair and hair treated with the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite in Example 10 under the condition of 10 s irradiation by a 300 W xenon light source were recorded by an infrared camera. As shown in Figure 12 a, the surface temperature rise rate of the hair treated with the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite in Example 10 was significantly accelerated. After only 10 s of illumination, its temperature was at least 2.3 °C higher than that of the untreated hair, highlighting the excellent photothermal conversion and heat conduction capabilities of the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite of the present invention. Subsequently, the hair sample was heated to near human skin temperature (about 37 °C) under the same 300 w xenon light illumination condition, and then the light source was turned off, and the cooling process was captured by an infrared thermal imager. As shown in Figure 12 a, it was observed that 10 s after the light was turned off, the average temperature of the hair treated with the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite in Example 10 was 1.6 °C lower than that of the untreated hair sample, indicating that the hair treated with the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite in Example 10 could return to room temperature level more quickly. These series of experimental results fully demonstrate that the hair treated with the alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on the MXene composite of the present invention endows the hair with excellent thermal management effects.

[0071] As Figure 13As shown, a surface DC voltmeter was used to test the static voltage of hair samples after being combed 10 times with a plastic comb to evaluate the static charge accumulation under different treatment conditions. The hair samples were untreated hair and hair treated with the MXene composite-based alternating electrostatic layer-by-layer assembly gradient hair dyeing method of Example 10. Among them, Coated represents the hair treated with the MXene composite-based alternating electrostatic layer-by-layer assembly gradient hair dyeing method of Example 10. The experimental results show that the surface static voltage of untreated hair is as high as about 1.32 kV after combing, while for the hair sample treated with the MXene composite-based alternating electrostatic layer-by-layer assembly gradient hair dyeing method of Example 10, its surface static voltage is significantly reduced to only 0.21 kV, indicating that this hair dye effectively inhibits the static charge accumulation on hair and improves the antistatic performance of hair.

[0072] The MXene composite-based alternating electrostatic layer-by-layer assembly gradient hair dyeing method provided by the present invention not only achieves an efficient and long-lasting dyeing effect, but also has excellent wash-fastness, can significantly improve the smoothness of the hair surface, effectively enhance the mechanical properties of the hair, and at the same time has excellent photothermal conversion and thermal management effects, as well as significantly improved antistatic performance and other multiple remarkable advantages. These characteristics work together to ensure the unique value of the hair dye in the field of personal care products and meet the needs of modern consumers for high-quality and multifunctional beauty products.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that after reading the specification of this application, they can still modify the specific implementation manners of the present invention or make equivalent replacements, but these modifications or changes are all within the protection scope of the pending claims of this invention application.

Claims

1. An alternating electrostatic layer-by-layer assembly gradient hair dyeing method based on MXene composite, characterized in that It includes the following steps: S1. Spray the chitosan solution on the surface of the hair strands so that the chitosan solution wraps the hair strands and naturally penetrates; S2. Then spray the Ti3C2T x @ gallic acid complex on the surface of the hair strands so that the Ti3C2T x @ gallic acid complex wraps the hair strands; S3. Then alternately spray the chitosan solution and the Ti3C2T x @ gallic acid complex on the surface of the hair strands, so that the chitosan solution and the Ti3C2T x @ gallic acid complex alternately wrap the hair strands to form a gradient composite layer with at least 5 layers; The Ti3C2T x @ gallic acid complex is composed of Ti3C2T x and gallic acid connected by C-O-Ti coordination bonds.

2. The hair dyeing method according to claim 1, wherein In S1, the mass concentration of the chitosan solution is 0.1 - 0.5%; The pH value of the chitosan solution is 5.0 - 6.

0.

3. The hair dyeing method according to claim 1, characterized in that, In S1, the chitosan solution further contains an antioxidant.

4. The hair dyeing method according to claim 1, characterized in that, In S2, the interlayer spacing of the Ti3C2T x @gallic acid complex is 1.05 nm.

5. The hair dyeing method according to claim 1, wherein, In S2, the characteristic peak of the 002 crystal plane of the x x @ gallic acid complex is shown at 2θ = 6.06° ± 0.1°.

6. The hair dyeing method according to claim 1, characterized in that, After the chitosan solution is sprayed on the surface of the hair strands or the Ti3C2T x @ gallic acid complex is sprayed on the surface of the hair strands, a drying operation is also carried out.

7. The hair dyeing method according to claim 1, characterized in that, The Ti3C2T x The preparation method of the @gallic acid complex comprises the following steps: Mix the Ti3C2T x solution with the gallic acid solution to obtain Ti3C2T x @ gallic acid complex.

8. The hair dyeing method according to claim 7, characterized in that, The Ti3C2T x solution has a mass concentration of 0.05 - 0.25%; The mass concentration of the gallic acid solution is 0.1 - 0.5%.

9. The hair dyeing method according to claim 7, wherein The mass ratio of the Ti3C2T x to gallic acid is 1:0.8 - 1:

5.

10. The hair dyeing method according to claim 7, characterized in that, The surface of the Ti3C2T x contains at least hydroxyl groups.

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