CN113717383A

CN113717383A - Oxidative polymerization method of dopamine and application thereof

Info

Publication number: CN113717383A
Application number: CN202111181229.6A
Authority: CN
Inventors: 张拥军; 周晓曼
Original assignee: Tianjin Polytechnic University
Current assignee: Tianjin Polytechnic University
Priority date: 2021-10-11
Filing date: 2021-10-11
Publication date: 2021-11-30
Anticipated expiration: 2041-10-11
Also published as: CN113717383B

Abstract

The invention relates to an oxidative polymerization method of dopamine and application thereof. The oxidative polymerization process comprises the steps of: preparing a buffer solution with a pH value of more than 4; using the buffer solution as a solvent to prepare a solution containing Fe²⁺A solution of ions; in an atmospheric environment, adding Fe to the mixture²⁺And adding dopamine into the ionic solution, and polymerizing to obtain polydopamine. The oxidative polymerization of dopamine is carried out by the method provided by the invention, the rapid oxidative polymerization of dopamine can be realized while the advantages of simple and mild reaction conditions are kept, and particularly, the instantaneous polymerization can be realized under weak acidic and neutral conditions. The method provided by the invention can be used for depositing polydopamine on the surface of the material to be modifiedThe method realizes the modification of the surface of the material, has beneficial technical effects particularly on the aspects of dyeing of fabrics, dyeing of hair and the like, can quickly finish dyeing and dyeing under simple and mild conditions, and has excellent color fastness.

Description

Oxidative polymerization method of dopamine and application thereof

Technical Field

The invention relates to the technical field of dopamine oxidative polymerization, in particular to a dopamine oxidative polymerization method with simple, mild and rapid reaction conditions and application thereof, and especially application in surface modification of a material to be modified.

Background

Dopamine (DA for short) dissolved in an alkaline aqueous solution can be subjected to spontaneous oxidative polymerization under the action of oxygen to generate polydopamine. Polydopamine (PDA for short) has a series of unique physicochemical properties, including simple preparation, good adhesion, chemical reaction activity, metal chelating capacity, biocompatibility, biodegradability, free radical capturing capacity, photothermal conversion capacity and the like.

Therefore, the deposition of dopamine on the surface of a material by utilizing the spontaneous oxidative polymerization of dopamine has become a common surface modification method. In 2007 Lee et al disclose a method for Surface modification of various materials using dopamine in alkaline solutions (see Lee, H., et al, Mussel-incorporated Surface Chemistry for multifunctionality coatings, science,2007, Vol.318 (5849): page 426 and 430).

Polydopamine has a structure similar to that of melanin in the human body and is considered to be an artificial melanin. Therefore, the fabric can be dyed by utilizing the oxidative polymerization of dopamine, and the serious environmental pollution problem existing in the existing fabric dyeing method can be expected to be solved. For example, Yan et al disclose the use of Fe at higher temperatures (50 ℃ C.)³⁺A method for dyeing Silk fabrics by oxidative Polymerization of Dopamine under the action of sodium perborate as an oxidizing agent (Yan et al, dye-Dyed and functionalized Silk with Rapid Oxidation Polymerization, Polymers,2018, Vol. 10, No. 7, p. 728).

Polydopamine as artificial melanin is also a hair dye with great application prospect. The existing hair dyes in the mainstream all contain substances such as p-phenylenediamine, and the substances have carcinogenicity and sensitization, and the safety of the substances is always a question of public doubt. The dopamine hair dye is expected to be a substitute product with high safety.

Im et al first disclosed the use of polydopamine as an artificial melaninA method for dyeing hair. They first dissolved DA in Tris-HCl buffer at pH 8.1, allowed DA to polymerize in this alkaline buffer for 6 hours, and then treated hair for 1 hour. For improving dyeing effect, Fe is added into hair while putting into hair²⁺Metal ions are generated to promote the Deposition of PDA on Hair by Chelation of these Metal ions (see Im, et al, Metal-chemistry-Assisted Deposition of Polydopamine on Human Hair: AReady-to-Use Eumelanin-Based Hair Dyeing method, ACS Biomaterials Science&Engineering,2017, vol 3, No. 4, p 628-636).

Gao et al disclose the use of CuSO under alkaline conditions₄/H₂O₂A method for dyeing hair by accelerating polymerization of dopamine can finish dyeing in about 5 minutes (refer to Gao, et al, Rapid prediction of multiple coating as a multifunctionality hair dye, RSC Advances, 2019, volume 9, 35, 20492 and 20496).

Dong et al disclose a method for dyeing hair using sodium periodate to promote polymerization of dopamine under weakly acidic conditions, which can be accomplished in 30 minutes (see Dong, et al, Melanin-mimetic multicolor and low-toxicity hair dye, RSC Advances, vol.2019, vol.9, 58, p.33617-33624).

Battistella et al disclose a method for dyeing Hair by polymerizing dopamine under alkaline conditions (3-6 wt% ammonia water) at a temperature of 37-40 ℃ for 2 hours (see Battistella, et al, Mimicking Natural Human Hair harvesting with Synthetic Melanin, ACS Central Science, 2020, Vol.6, No. 7, p. 1179-1188).

Surface modification including dyeing and coloring by oxidative polymerization of dopamine has many advantages, but has a serious problem of slow reaction speed. The usual method is spontaneous redox under alkaline conditions (e.g. pH 8.5) with oxygen in air as the oxidant, which takes hours or even days. For this purpose, methods have been proposed which use strong oxidizers to accelerate the reaction, such as the abovementioned use of Fe³⁺Sodium perborate, CuSO₄/H₂O₂And strong oxidants such as sodium periodate. These methods are effective in increasing the reaction rate, but the use of a strong oxidizing agent makes the reaction conditions severe and may destroy the structure of the surface-modified material such as fabric or hair. The use of alkaline conditions may also disrupt the structure of the surface modified material, such as fabric or hair.

Disclosure of Invention

Problems to be solved by the invention

In view of the above-mentioned drawbacks of the prior art, the present invention provides an oxidative polymerization method of dopamine, so as to achieve rapid polymerization of dopamine under simple and mild reaction conditions. The invention also aims to provide the application of the dopamine oxidative polymerization method in surface modification.

Means for solving the problems

The inventors of the present invention have found, through intensive studies, that Fe is used in an atmospheric environment using oxygen in the air as an oxidizing agent²⁺The ion is used as a catalyst to catalyze the oxidative polymerization reaction of dopamine in a buffer solution with the pH value of more than 4, so that the rapid polymerization of dopamine can be completed under simple and mild reaction conditions. The method well solves the problems that the reaction speed of the spontaneous oxidative polymerization of dopamine in the prior art is low, the reaction conditions are severe, and a strong oxidant needs to be added.

The invention provides a dopamine oxidative polymerization method, which comprises the following steps:

preparing a buffer solution with a pH value of more than 4;

using the buffer solution as a solvent to prepare a solution containing Fe²⁺A solution of ions;

in an atmospheric environment, adding Fe to the mixture²⁺And adding dopamine into the ionic solution, and polymerizing to obtain polydopamine.

The method according to the present invention, wherein only atmospheric oxygen is used as an oxidizing agent when dopamine is added to polymerize polydopamine.

The invention also provides application of polydopamine in surface modification, wherein the polydopamine is obtained by the dopamine oxidative polymerization method.

The use according to the invention, wherein the pH of the buffer solution is in the range of 4 to 8.

The use according to the present invention, wherein the composition comprises Fe²⁺The Fe in solution of ions²⁺The concentration of the ions is 10^-4To 10^-1In the range of mol/L.

The use according to the invention, wherein with respect to the inclusion of Fe²⁺A solution of ions and a total mass of dopamine added, said mass percentage concentration of dopamine being in the range of 0.01 wt% to 4 wt%.

The use according to the invention, wherein the surface modification comprises deposition of polydopamine on the surface of the material to be modified.

The use according to the present invention, wherein the surface modification comprises deposition of polydopamine on a fabric.

The use according to the invention, wherein the surface modification comprises deposition of polydopamine on the hair.

ADVANTAGEOUS EFFECTS OF INVENTION

The method provided by the invention is used for carrying out the oxidative polymerization of dopamine, only oxygen in the atmosphere is used as an oxidizing agent, any other oxidizing agent is not required to be added, and Fe is used²⁺The ion is used as a catalyst, so that the rapid oxidative polymerization of dopamine can be realized while the advantages of simple and mild reaction conditions are kept, and particularly, the instantaneous polymerization can be realized when the reaction is carried out under weak acidic and neutral conditions.

The method provided by the invention can realize the modification of the material surface by depositing the polydopamine on the surface of the material to be modified, has beneficial technical effects particularly on the aspects of dyeing of fabrics, dyeing of hair and the like, can realize the rapid completion of dyeing and dyeing under simple and mild conditions, and has excellent color fastness.

Drawings

Fig. 1 shows the results of the oxidative polymerization kinetics of dopamine catalyzed by different metal ions at pH 5.

Fig. 2 shows the results of different metal ions catalyzing oxidative polymerization of dopamine at pH 5 for 15 minutes.

FIG. 3 shows Fe²⁺The ions catalyze the oxidative polymerization kinetics of dopamine under different pH values.

Fig. 4 shows the results of the oxidative polymerization kinetics of dopamine catalyzed by different metal ions at pH 7.

Fig. 5 shows the results of different metal ions catalyzing oxidative polymerization of dopamine at pH 7 for 15 minutes.

FIG. 6 shows Fe at different pH values²⁺Oxidative polymerization kinetics of ion catalyzed dopamine results.

FIG. 7 shows the addition of Fe²⁺Ionic, no addition of Fe²⁺Ion, addition of Fe²⁺Ions and EDTA, addition of Fe²⁺Oxidative polymerization kinetics of dopamine under ionic and nitrogen-charged conditions.

FIG. 8 shows Fe at various concentrations at pH 5²⁺Kinetics of oxidative polymerization of dopamine under ion catalysis.

FIG. 9 shows Fe at various concentrations at pH 5²⁺The amount of polydopamine produced under ionic catalysis.

FIG. 10 shows Fe at various concentrations at pH 7²⁺Kinetics of oxidative polymerization of dopamine under ion catalysis.

FIG. 11 shows Fe at various concentrations at pH 7²⁺The amount of polydopamine produced under ionic catalysis.

FIG. 12 shows Fe at pH 5²⁺The ions catalyze the oxidative polymerization kinetics of varying concentrations of dopamine.

FIG. 13 shows Fe at pH 7²⁺The ions catalyze the oxidative polymerization kinetics of varying concentrations of dopamine.

FIG. 14 shows pH values at different pH values and notSame Fe²⁺The deposition speed of polydopamine on the silicon wafer under the condition of ion concentration.

FIG. 15 shows dopamine at different concentrations of Fe²⁺The three fabrics are dyed by oxidative polymerization under the catalysis of ions.

FIG. 16 shows a cross-section at Fe²⁺Effect of dye time on three fabrics when the ions catalyze oxidative polymerization of dopamine to dye.

Figure 17 shows the effect of washing powder washing on the colour of polydopamine dyed fabrics.

FIG. 18 shows dopamine at different concentrations of Fe²⁺The hair dyeing effect is realized by the oxidative polymerization under the ion catalysis.

Fig. 19 shows the effect of hair dyeing time on hair dyeing effect.

Fig. 20 shows the effect of dopamine concentration on hair coloring effect.

Figure 21 shows the effect of wash times on the color of polydopamine-stained hair.

Detailed Description

The invention relates to an oxidative polymerization method of dopamine, which comprises the following steps:

preparing a buffer solution with a pH value of more than 4;

The technical idea of the method provided by the invention is that Fe is used by taking oxygen in air as an oxidant in the atmospheric environment²⁺The ion is used as a catalyst to catalyze the oxidative polymerization reaction of dopamine in a buffer solution with the pH value of more than 4, so that the rapid polymerization of dopamine is completed under simple and mild reaction conditions. The method well solves the problems that the reaction speed of the spontaneous oxidative polymerization of dopamine in the prior art is low, the reaction conditions are severe, and a strong oxidant needs to be added.

In the oxidative polymerization process of the present invention, a pH of4 or more buffer solution as solvent to prepare Fe²⁺A solution of ions. When the pH of the buffer solution is less than 4, it is difficult to effectively catalyze the oxidative polymerization of dopamine, and the polymerization reaction rate is extremely slow.

In the oxidative polymerization process of the present invention, it is preferable that only oxygen in the air is used as a catalyst without adding any other oxidizing agent.

The kind of the buffer solution is not particularly limited, and a buffer solution generally used in the art may be used as long as the pH of the buffer solution is 4 or more. Examples of the kind of the buffer solution include an acetic acid/sodium acetate buffer solution, a Tris-HCl buffer solution, and the like.

The concentration of the buffer solution is not particularly limited, and is preferably in the range of 0.05mol/L to 0.5 mol/L.

In the oxidative polymerization process of the present invention, the formulation comprises Fe²⁺In ionic solution, for containing Fe²⁺The metal salt of the ion is not particularly limited, and examples thereof include FeCl₂、FeSO₄、FeBr₂And the like.

In the oxidative polymerization method of the present invention, the polymerization reaction rate of dopamine increases with the increase in pH of the buffer solution, preferably, pH of the buffer solution is in the range of 4 to 12, more preferably, pH is in the range of 4 to 10, and particularly preferably, pH is in the range of 6 to 9, and instantaneous oxidative polymerization of dopamine can be achieved.

In the oxidative polymerization method of the present invention, preferably, the polymer contains Fe²⁺The Fe in solution of ions²⁺The concentration of the ions is 10^-4To 10^-1In the range of mol/L. When said Fe is present²⁺The concentration of the ions is 10^-4To 10^-1In the mol/L range, the polydopamine can be produced in an appropriate amount at an economical cost. If the concentration is less than 10^-4If the mol/L is less than the threshold value, the amount of the generated polydopamine is too low; if the concentration is higher than 10^-1The mol/L is that the generation amount of polydopamine is close to the peak value, and then the Fe is further improved²⁺The concentration of ionsThe production of polydopamine can not be obviously improved any more, but the cost is increased unnecessarily. More preferably, the iron-containing particles comprise Fe²⁺The Fe in solution of ions²⁺The concentration of the ions is 10^-4To 10^-2In the range of mol/L. Particularly preferably, the Fe²⁺The concentration of the ions is 10^-3To 10^-2In the range of mol/L.

In the oxidative polymerization method of the present invention, the Fe is added to the composition in an atmospheric environment²⁺Adding dopamine into the ionic solution to polymerize to obtain polydopamine, preferably relative to the Fe-containing solution²⁺A solution of ions and dopamine in a mass percent concentration in the range of 0.01 wt% to 4 wt%. When the concentration of dopamine is in the range of 0.01 wt% to 4 wt%, a suitable amount of polydopamine can be produced at an economical cost. If the concentration is less than 0.01 wt%, the amount of polydopamine produced is too low; if the concentration is higher than 4 wt%, the production of polydopamine is close to the peak value, and further increase of the dopamine concentration can not lead to significant increase of the production of polydopamine, but rather increases the cost. More preferably, with respect to said inclusion of Fe²⁺A solution of ions and dopamine in a mass percent concentration in the range of 0.1 to 2 wt%. Particularly preferably, the dopamine concentration is in the range of 0.2 wt% to 2 wt%.

As a non-limiting example, the process for oxidative polymerization of dopamine of the present invention comprises the steps of:

preparing Tris-HCl buffer solution with pH value of 4 or more and concentration of 0.1mol/L or acetic acid/sodium acetate buffer solution with concentration of 0.2mol/L, and preparing solution containing Fe with the buffer solution as solvent²⁺A solution of ions, preferably, wherein Fe²⁺The concentration of the ions is 10^-4To 10^-1And adding dopamine into the solution at mol/L in an atmospheric environment, preferably, the concentration of the dopamine in the solution is 0.01 wt% to 4 wt%, and polymerizing to obtain polydopamine.

The invention also provides application of the polydopamine obtained by the dopamine oxidative polymerization method in surface modification.

In the application of the polydopamine in surface modification, preferably, the pH value of the buffer solution is in the range of 4 to 9, and when the buffer solution is used as a solvent, the buffer solution is prepared to contain Fe²⁺In ionic solution, preferably, the solution contains Fe² ⁺The Fe in solution of ions²⁺The concentration of the ions is 10^-4To 10^-1In the range of mol/L; placing the material to be modified in the container containing Fe²⁺Adding dopamine into the ionic solution to ensure that the solution contains Fe²⁺A solution of ions and dopamine in a mass percent concentration in the range of 0.01 wt% to 4 wt%. When the material to be modified comprises Fe²⁺Soaking in the solution of ions and dopamine for 2 minutes to 2 hours, then taking out, washing with water and airing. The polydopamine is deposited on the surface of the material to be modified so as to realize the surface modification of the material to be modified. Materials to be modified include, without limitation, silicon wafers, fabrics, hair, and the like.

In the application of the polydopamine in surface modification, the pH value of the buffer solution is preferably in the range of 5 to 8, and more preferably in the range of 6 to 8.

Preferably, the buffer solution has a pH in the range of 5 to 8, Fe²⁺The concentration of the ions is 10^-4To 10^-2In the range of mol/L, the dopamine concentration is in the range of 0.1 wt% to 2 wt%, and in case these preferred conditions are met, the modification can be achieved in 2 to 20 minutes.

The application of the polydopamine in surface modification comprises the step of depositing the polydopamine on a fabric, so that the fabric is dyed.

Preferably, the buffer solution has a pH in the range of 4 to 9, Fe²⁺The concentration of the ions is 10^-4To 10^-1In the range of mol/L, placing the fabric in the composition containing Fe²⁺Adding dopamine into the ionic solution, wherein the concentration of the dopamine is in the range of 0.01-4 wt%, and when the fabric contains Fe²⁺Soaking in the solution of ions and dopamine for 2 minutes to 2 hours, then taking out, washing with water and airing. The polydopamine is deposited on the surface of the fabric to achieve surface modification of the fabric.

More preferably, the buffer solution has a pH in the range of 5 to 8, Fe²⁺The concentration of the ions is 10^-3To 10^-2In the mol/L range, the concentration of the dopamine is in the range of 0.2 wt% to 2 wt%, and under the conditions meeting the requirements, the modification of the fabric, namely the dyeing of the fabric can be completed within 2 to 20 minutes.

The application of the polydopamine in surface modification comprises the step of depositing the polydopamine on hair, so that the hair is dyed.

Preferably, the buffer solution has a pH in the range of 6 to 8, Fe²⁺The concentration of the ions is 10^-4To 10^-1Soaking hair in the solution at mol/L, adding dopamine at a concentration of 0.01-4 wt%, and adding Fe²⁺Soaking in the solution of ions and dopamine for 2 minutes to 2 hours, then taking out, washing with water and airing. The polydopamine is deposited on the surface of the hair to effect surface modification of the hair.

More preferably, the buffer solution has a pH in the range of 7 to 7.5, Fe²⁺The concentration of the ions is 10^-3To 10^-2In the range of mol/L, the dopamine concentration is in the range of 0.2 wt% to 2 wt%, and under the conditions satisfying these preferences, the modification of the hair, i.e. the dyeing of the hair, can be accomplished in 2 to 30 minutes.

Examples

The present invention is further described in detail below with reference to specific examples, but the technical solution of the present invention is by no means limited to the following examples. It should be noted that the reagents, raw materials and equipment used in the examples are conventional products commercially available unless otherwise specified.

Example 1

(1) Preparation of Fe²⁺Ion concentration of 10^-4A 0.2mol/L acetic acid/sodium acetate buffer solution with pH value of 5 at 25 deg.CAdding dopamine into the solution to enable the concentration of the dopamine in the solution to be 0.5 wt%, and detecting the oxidative polymerization reaction kinetics of the dopamine in the solution by using an ultraviolet spectrophotometer.

(2) Separately preparing Fe³⁺、Zn²⁺、Cu²⁺、Al³⁺、Ba²⁺、Mg²+、Ca²⁺、Ni²⁺、Cr³⁺Ion concentration of 10^-4Adding dopamine into each solution at 25 ℃ so that the concentration of the dopamine in each solution is 0.5 wt% respectively, and detecting the oxidative polymerization reaction kinetics of the dopamine in each solution by using an ultraviolet spectrophotometer respectively.

Fig. 1 shows the results of the oxidative polymerization kinetics of dopamine catalyzed by different metal ions at pH 5. Fig. 2 shows the results of different metal ions catalyzing oxidative polymerization of dopamine at pH 5 for 15 minutes.

The UV measurements shown in FIG. 1 indicate that when dopamine is added to the solution containing Fe²⁺After the ion buffer solution, the absorbance of the solution rapidly rises, and after 5 minutes, the solution is close to saturation; when dopamine is added to the composition containing Fe³⁺After the ion buffer solution, the absorbance of the solution slowly increased, and the rate of increase in absorbance was significantly lower than that of the solution containing Fe²⁺A buffer solution of ions; when dopamine is added to a buffer solution containing other metal ions, the absorbance of the solution does not substantially change.

As can be seen from the photographs shown in FIG. 2, after dopamine was added to the buffer solution containing different metal ions for 15 minutes, Fe was contained²⁺The buffer solution of ions, which contained Fe, turned significantly black in color³⁺The color of the buffer solution (2) was slightly blackened, and the buffer solution containing other metal ions was hardly discolored.

The above results show that Fe is present at a pH of 5²⁺The presence of ions can rapidly catalyze the oxidative polymerization of dopamine.

Example 2

Separately preparing Fe²⁺Ion concentration of 10^-4Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH values of 3, 4, 5, 6, 7, 8 and 9 respectively or acetic acid/sodium acetate with the concentration of 0.2mol/L are added into each solution respectively at 25 ℃, so that the concentration of the dopamine in each solution is 0.5 wt%, and the oxidative polymerization reaction kinetics of the dopamine in each solution is detected by an ultraviolet spectrophotometer respectively.

The UV measurements shown in FIG. 3 indicate that Fe is present at pH 3²⁺The absorbance of the ion buffer solution is basically unchanged, and the ion buffer solution hardly plays a role in catalyzing the oxidative polymerization of dopamine. Containing Fe at pH 4²⁺The absorbance of the ion buffer solution gradually increased, indicating that the oxidative polymerization of dopamine was catalyzed at a pH of 4. The absorbance is obviously increased along with the gradual increase of the pH value, which indicates that the oxidative polymerization reaction speed is gradually increased, and when the pH value is more than or equal to 6, particularly when the pH value is 6, 7, 8 and 9, the instantaneous oxidative polymerization of dopamine can be realized.

Example 3

(1) Preparation of Fe²⁺Ion concentration of 10^-4The oxidative polymerization reaction kinetics of the dopamine in the solution are detected by an ultraviolet spectrophotometer, wherein the concentration of the dopamine in the solution is 0.5 wt% by adding the dopamine to the Tris-HCl buffer solution with the mol/L pH value of 7 and the concentration of the Tris-HCl buffer solution is 0.1mol/L at the temperature of 25 ℃.

(2) Separately preparing Fe³⁺、Zn²⁺、Cu²⁺、Al³⁺、Ba²⁺、Mg²+、Ca²⁺、Ni²⁺、Cr³⁺Ion concentration of 10^-4And (3) respectively adding dopamine into each solution at 25 ℃ so that the concentration of the dopamine in each solution is 0.5 wt% by using a Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7 of mol/L, and respectively detecting the oxidative polymerization reaction kinetics of the dopamine in each solution by using an ultraviolet spectrophotometer.

Fig. 4 shows the results of the oxidative polymerization kinetics of dopamine catalyzed by different metal ions at pH 7. Fig. 5 shows the results of different metal ions catalyzing oxidative polymerization of dopamine at pH 7 for 15 minutes.

The UV measurements shown in FIG. 4 indicate that when dopamine is added to the solution containing Fe²⁺After the ion buffer solution, the absorbance of the solution rapidly rises and almost immediately approaches saturation; when dopamine is added to the composition containing Fe³⁺After the ion buffer solution, the absorbance of the solution gradually increases, and the rate of increase in absorbance is lower than that of the solution containing Fe²⁺A buffer solution of ions; when dopamine is added to a buffer solution containing other metal ions, the absorbance of the solution increases slightly.

As can be seen from the photographs shown in FIG. 5, after dopamine was added to the buffer solution containing different metal ions for 15 minutes, Fe was contained²⁺The buffer solution of ions, which contained Fe, turned significantly black in color³⁺The color of the buffer solution (2) was slightly blackened, and the buffer solution containing other metal ions was hardly discolored.

The above results show that Fe is present at pH 7²⁺The presence of ions can effect transient oxidative polymerization of dopamine.

Example 4

Separately preparing Fe²⁺Ion concentration of 10^-40.2mol/L acetic acid/sodium acetate buffer solution with pH values of 4, 5, 6, 7 and 8 or 0.1mol/L Tris-HCl buffer solution, adding dopamine into each solution at 25 ℃ to enable the concentration of the dopamine in each solution to be 0.5 wt%, and detecting the oxidative polymerization reaction kinetics of the dopamine in each solution by using an ultraviolet spectrophotometer.

The UV detection results shown in FIG. 6 indicate that Fe is contained at pH 4²⁺The buffer solution of the ion can catalyze the oxidative polymerization of dopamine. The oxidation polymerization reaction speed is gradually increased along with the gradual increase of the pH value, and when the pH value is more than or equal to 6, particularly when the pH value is 6, 7 or 8, the instantaneous oxidation polymerization of the dopamine can be realized.

Example 5

(2) Preparing a Tris-HCl buffer solution with the pH value of 7 and the concentration of 0.1mol/L, adding dopamine into the solution at 25 ℃ to enable the concentration of the dopamine in the solution to be 0.5 wt%, and detecting the oxidative polymerization reaction kinetics of the dopamine in the solution by using an ultraviolet spectrophotometer.

(3) Preparation of Fe²⁺Ion concentration of 10^-4A Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7, and ethylene diamine tetraacetic acid (EDTA for short) is added into the solution to ensure that the concentration of the EDTA in the solution is 10^-3mol/L, further, dopamine was added at 25 ℃ so that the concentration of dopamine in the solution was 0.5 wt%, and the oxidative polymerization kinetics of dopamine in the solution was examined with an ultraviolet spectrophotometer.

(4) Preparation of Fe²⁺Ion concentration of 10^-4The method comprises the steps of adding dopamine into a Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7 at 25 ℃ under the condition of introducing nitrogen into the solution to remove oxygen, enabling the concentration of the dopamine in the solution to be 0.5 wt%, and detecting the oxidative polymerization reaction kinetics of the dopamine in the solution by using an ultraviolet spectrophotometer.

FIG. 7 shows the addition of Fe as described above, respectively²⁺Ionic, no addition of Fe²⁺Ion, addition of Fe²⁺Ions and EDTA, addition of Fe²⁺Oxidative polymerization kinetics of dopamine under various conditions of ionic and nitrogen flux.

The UV measurements shown in FIG. 7 show that when dopamine is added to the solution containing Fe²⁺After the buffer solution of ions, the absorbance of the solution rapidly increased, almost immediately approaching saturation, thus demonstrating oxygen and Fe in the atmosphere²⁺Catalysis of oxidative polymerization of dopamine in the presence of ionsUsing; when dopamine is added and Fe is not contained²⁺After the ion is buffered, the absorbance of the solution is not substantially changed; when dopamine is added to the composition containing Fe²⁺After the buffer solution of the ions and EDTA, the absorbance of the solution was not substantially changed, since Fe²⁺Complexing with EDTA, and therefore not catalyzing the oxidative polymerization of dopamine; when dopamine is added to the composition containing Fe²⁺The absorbance of the solution is not substantially changed after the ion and nitrogen are simultaneously introduced into the deoxygenated buffer solution, since no oxygen is present as an oxidizing agent, and therefore even if Fe is present in the solution²⁺The ion can not play a role in catalyzing the oxidative polymerization reaction of dopamine.

Example 6

Preparation of Fe²⁺Ions are 0 and 10 respectively^-4mol/L、2×10^-4mol/L、5×10^-4mol/L、10^-3mol/L、2×10^- ³mol/L、5×10^-3mol/L、10^-2Adding dopamine into each solution at 25 ℃ so that the concentration of the dopamine in each solution is 0.5 wt% by using an acetic acid/sodium acetate buffer solution with the mol/L pH value of 5 and the concentration of 0.2mol/L, and detecting the oxidative polymerization reaction kinetics of the dopamine in each solution by using an ultraviolet spectrophotometer.

The UV detection results shown in FIG. 8 show that Fe is not present in the buffer solution²⁺When ionic, the absorbance of the solution is substantially unchanged, i.e., the oxidative polymerization of dopamine hardly occurs, in the presence of Fe²⁺In the case of ions, the absorbance gradually increased, indicating that oxidative polymerization of dopamine occurred, with Fe²⁺The ion concentration is increased, the absorbance is obviously increased, and the oxidative polymerization reaction speed of the dopamine is obviously improved.

FIG. 9 shows Fe at various concentrations at pH 5²⁺The amount of polydopamine produced under ionic catalysis. The absorbance of the solution after 15 minutes of reaction was used as an indicator. FIG. 9 showsIs doped with Fe²⁺The absorbance increased significantly with increasing concentration, indicating that with Fe²⁺The increase in the ion concentration significantly increases the oxidative polymerization rate of dopamine, and thus the amount of polydopamine produced in the same reaction time is significantly increased.

Example 7

Preparation of Fe²⁺The ion concentrations are 0 and 10 respectively^-4mol/L、2×10^-4mol/L、5×10^-4mol/L、10^-3mol/L、2×10^-3mol/L、5×10^-3mol/L、10^-2The oxidative polymerization reaction kinetics of the dopamine in each solution are detected by an ultraviolet spectrophotometer, wherein the molar/L Tris-HCl buffer solution with the pH value of 7 and the concentration of 0.1mol/L is added into each solution at 25 ℃, so that the concentration of the dopamine in each solution is 0.5 wt%.

The UV detection results shown in FIG. 10 indicate that Fe is not present in the buffer solution²⁺When ionic, the absorbance of the solution is substantially unchanged, i.e., the oxidative polymerization of dopamine hardly occurs, in the presence of Fe²⁺In the case of ions, the absorbance increased significantly, indicating that oxidative polymerization of dopamine occurred, with Fe²⁺The ion concentration is increased, the absorbance is obviously increased, and the oxidative polymerization reaction speed of the dopamine is obviously improved.

FIG. 11 shows Fe at various concentrations at pH 7²⁺The amount of polydopamine produced under ionic catalysis. The absorbance of the solution after 15 minutes of reaction was used as an indicator. FIG. 11 shows the evolution of Fe²⁺The absorbance increased significantly with increasing concentration, indicating that with Fe²⁺The increase in the ion concentration significantly increases the oxidative polymerization rate of dopamine, and thus the amount of polydopamine produced in the same reaction time is significantly increased.

Example 8

Preparation of Fe²⁺Ion concentration of 10^-4A 0.2mol/L acetic acid/sodium acetate buffer solution with a pH value of 5 at 25 deg.CDopamine is added into the solutions to enable the concentration of the dopamine in each solution to be 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0, 2.0 and 3.0 wt%, and the oxidative polymerization reaction kinetics of the dopamine in each solution are detected by an ultraviolet spectrophotometer.

The uv measurements shown in fig. 12 show that the absorbance increases with increasing dopamine concentration, indicating an increase in the rate of oxidative polymerization of dopamine.

Example 9

Preparation of Fe²⁺Ion concentration of 10^-4Adding dopamine into a Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7 at 25 ℃ so that the concentration of the dopamine in each solution is 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0, 2.0 and 3.0 wt%, and detecting the oxidative polymerization reaction kinetics of the dopamine in each solution by using an ultraviolet spectrophotometer.

The uv measurement results shown in fig. 13 show that the absorbance is instantaneously and significantly increased as the concentration of dopamine increases, indicating that the oxidative polymerization of dopamine is instantaneously completed.

Example 10

Placing the silicon wafer in boiling piranha solution (i.e. H with volume ratio of 3: 7)₂O₂-H₂SO₄Mixed solution) for about 1 hour, thoroughly rinsed with deionized water, and dried for use.

(1) Preparation of Fe²⁺Ion concentration of 10^-4Putting a silicon wafer into the solution, adding dopamine into the solution at 25 ℃ to enable the concentration of the dopamine in the solution to be 0.5 wt%, taking out the silicon wafer after the silicon wafer is put into the solution for different time, washing the silicon wafer with deionized water, and drying the silicon wafer with nitrogen. Measuring different standing times of silicon wafer in solution by using ellipsometerThickness of the poly dopamine layer deposited on the surface of the silicon wafer.

(2) Preparing 0.2mol/L acetic acid/sodium acetate buffer solution with pH value of 5, placing a silicon wafer in the solution, adding dopamine into the solution at 25 ℃ to enable the concentration of the dopamine in the solution to be 0.5 wt%, taking out the silicon wafer after the silicon wafer is placed in the solution for different time, washing with deionized water, and drying with nitrogen. And (3) measuring the thickness of the poly dopamine layer deposited on the surface of the silicon wafer after the silicon wafer is kept stand in the solution for different times by using an ellipsometer.

(3) Preparation of Fe²⁺Ion concentration of 10^-4Putting a silicon wafer into a Tris-HCl buffer solution with the mol/L pH value of 7 and the concentration of 0.1mol/L, adding dopamine into the solution at 25 ℃ to ensure that the concentration of the dopamine in the solution is 0.5 wt%, taking out the silicon wafer after the silicon wafer is put into the solution for different times, washing the silicon wafer with deionized water, and drying the silicon wafer with nitrogen. And (3) measuring the thickness of the poly dopamine layer deposited on the surface of the silicon wafer after the silicon wafer is kept stand in the solution for different times by using an ellipsometer.

(4) Preparing a Tris-HCl buffer solution with the pH value of 7 and the concentration of 0.1mol/L, placing a silicon wafer into the solution, adding dopamine into the solution at 25 ℃ to enable the concentration of the dopamine in the solution to be 0.5 wt%, taking out the silicon wafer after the silicon wafer is placed in the solution for different times, washing the silicon wafer with deionized water, and drying the silicon wafer with nitrogen. And (3) measuring the thickness of the poly dopamine layer deposited on the surface of the silicon wafer after the silicon wafer is kept stand in the solution for different times by using an ellipsometer.

(5) The method comprises the steps of depositing a poly-dopamine layer on the surface of a silicon wafer by adopting a conventional method in the prior art, namely preparing a Tris-HCl buffer solution with the pH value of 8.5 and the concentration of 0.1mol/L, placing the silicon wafer into the solution, adding dopamine into the solution at 25 ℃ to enable the concentration of the dopamine in the solution to be 0.5 wt%, taking out the silicon wafer after the silicon wafer is placed in the solution for different times, washing the silicon wafer with deionized water, and drying the silicon wafer with nitrogen. And (3) measuring the thickness of the poly dopamine layer deposited on the surface of the silicon wafer after the silicon wafer is kept stand in the solution for different times by using an ellipsometer.

FIG. 14 shows a comparison of the deposition rate of polydopamine on silicon wafers under the various conditions described above.

As shown in FIG. 14, in the case of Fe²⁺The poly dopamine layer deposited on the surface of the silicon wafer in the ionic buffer solution rapidly increased in thickness, saturated at 10 minutes, reaching 31.8nm at a pH of 5 and 38.1nm at a pH of 7.

In contrast, in the absence of Fe²⁺In the ion buffer solution, the thickness of the poly dopamine layer deposited on the surface of the silicon wafer is slowly increased. After 10 minutes, the thickness of the polydopamine layer was 0.3nm (pH 5), 1.5nm (pH 7) and 3.1nm (pH 8.5), respectively.

Converted to that containing no Fe²⁺The buffer solution of ions contained therein at a concentration of 10^-4Fe of M²⁺In the ionic buffer solution, under the condition that the pH value is 5, the deposition speed of the polydopamine layer is increased by 105 times; under the condition of pH value of 7, the deposition speed of the polydopamine layer is increased by 24 times.

The above results demonstrate that addition of Fe²⁺The ions can greatly catalyze the oxidative polymerization reaction of dopamine, so that the deposition speed of polydopamine on the surface of a silicon wafer is increased, and the rapid surface modification of the surface of the silicon wafer is realized. Under both neutral conditions of pH 7 and weakly acidic conditions of pH 5, rapid surface modification can be achieved.

Example 11

And (3) carrying out ultrasonic treatment on the cotton/polyester blended fabric, the cotton cloth and the linen respectively in absolute ethyl alcohol or acetone for 30 minutes, and then naturally airing for later use.

Placing the three fabrics in Fe respectively²⁺Ion concentrations of 10 respectively^-4mol/L、5×10^-4mol/L10^-3mol/L、2×10^-3mol/L and 5X 10^-3Stirring for 15 minutes in a Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7, respectively adding dopamine into each solution to ensure that the concentration of the dopamine in the solution is 0.5 wt%, stirring for 15 minutes, taking out the fabric, washing with deionized water, and naturally drying.

Photographs of each fabric are shown in FIG. 15, and FIG. 15 shows dopamineFe at various concentrations²⁺The three fabrics are dyed by oxidative polymerization under the catalysis of ions.

As shown in FIG. 15, Fe at various concentrations²⁺Under the catalysis of ions, dopamine is oxidized and polymerized to generate polydopamine which is deposited on the surface of each fabric so as to dye the fabric, and the polydopamine is accompanied by Fe²⁺The increase in the concentration of ions increases the thickness of the deposited polydopamine, which results in a darker colour of the fabric.

Example 12

Placing the three fabrics in Fe respectively²⁺Ion concentration of 2X 10^-3Stirring for 15 minutes in a Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7, respectively adding dopamine into each solution to ensure that the concentration of the dopamine in the solution is 0.5 wt%, stirring for 15 minutes, 1 hour, 3 hours and 5 hours, respectively, taking out the fabric, washing with deionized water, and naturally airing.

Photographs of each fabric are shown in fig. 16, and fig. 16 shows dopamine at the same concentration of Fe²⁺And (3) carrying out oxidative polymerization under the ion catalysis for different time, and then dyeing the three fabrics.

As shown in fig. 16, for cotton fabric, only 15 minutes of treatment was required to obtain a darker color; for cotton/polyester blended fabrics and linen fabrics, darker colors can be obtained after 3 hours of treatment.

Example 13

Placing the three fabrics in Fe respectively²⁺Ion concentration of 2X 10^-3Stirring for 15 minutes in a Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7, respectively adding dopamine into each solution to ensure that the concentration of the dopamine in each solution is 0.5 wt%, stirring for 15 minutes, taking out the fabric, washing with deionized water, and naturally drying.

And (3) putting the dyed fabrics into centrifuge tubes filled with 30ml of deionized water, adding 0.08g of washing powder, shaking for 5 minutes, taking out, and naturally drying. The washing operation was repeated three times.

Photographs of each of the fabrics after dyeing and before washing and after dyeing and after washing are shown in fig. 17, and fig. 17 shows the effect of washing powder washing on the fabric color.

As shown in FIG. 17, after washing, the color of each dyed fabric did not change significantly from that before washing, indicating that Fe was used²⁺The ion-catalyzed oxidative polymerization of dopamine can realize the rapid dyeing of different fabrics, and each fabric dyed by the polydopamine has better color fastness.

Example 14

Preparation of Fe²⁺Ion concentrations of 10 respectively^-4mol/L、5×10^-4mol/L、10^-3mol/L、2×10^-3mol/L、5×10^-3Adding a Tris-HCl buffer solution with the concentration of 0.1mol/L and the pH value of 7 into each solution, respectively adding platinum real human hair with the length of about 10cm and the color number of 613 into each solution to moisten the hair, respectively adding dopamine into each solution to ensure that the concentration of the dopamine in each solution is 0.5 wt%, stirring for 15 minutes, taking out the hair, washing with deionized water, and naturally drying.

Hair without dyeing treatment and hair containing different concentrations of Fe²⁺Photographs of the dyed treated hair in ionic buffer are shown in figure 18. FIG. 18 shows dopamine at different concentrations of Fe²⁺The hair dyeing effect is realized by the oxidative polymerization under the catalysis of ions.

As shown in FIG. 18, Fe is used²⁺The oxidative polymerization of dopamine is catalyzed by ions, the hair can be quickly dyed, and the color of the hair is changed along with Fe in the buffer solution²⁺The ion concentration increases.

Example 15

Preparation of Fe²⁺Ion concentration of 5X 10^-3A Tris-HCl buffer solution of 0.1mol/L concentration having a pH of 7, to which solution about 10c long was addedm, white gold true human hair with color number 613, wetting the hair, then adding dopamine to the solution so that the concentration of dopamine in the solution is 0.5 wt%, stirring for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes and 30 minutes respectively, taking out the hair, washing with deionized water, and naturally drying.

Photographs of hair treated with different time-courses of dyeing are shown in FIG. 19, and FIG. 19 shows the same concentration of Fe in dopamine²⁺The hair dyeing effect is the hair dyeing effect after oxidative polymerization is carried out for different time under the ion catalysis, namely the hair dyeing effect is influenced by the hair dyeing time.

As shown in FIG. 19, Fe is used²⁺The ion-catalyzed oxidative polymerization of dopamine can realize the rapid dyeing of hair, and the dyeing can be completed in only 5 minutes.

Example 16

Preparation of Fe²⁺Ion concentration of 5X 10^-3Adding a 0.1mol/L Tris-HCl buffer solution with the pH value of 7 into the solution, adding platinum real human hair with the length of about 10cm and the color number of 613 into the solution to moisten the hair, then adding dopamine into the solution to ensure that the concentration of the dopamine in the solution is 0.25 wt%, 0.5 wt%, 0.75 wt%, 1 wt% and 3 wt% respectively, stirring for 15 minutes, taking out the hair, washing with deionized water, and naturally drying.

Photographs of hair dyed in buffer solutions containing different concentrations of dopamine are shown in FIG. 20, and FIG. 20 shows Fe at the same concentration²⁺The hair dyeing effect is the hair dyeing effect of oxidative polymerization of dopamine with different concentrations under the catalysis of ions, namely the influence of the concentration of the dopamine on the hair dyeing effect.

As shown in FIG. 20, Fe is used²⁺The ion-catalyzed oxidative polymerization of dopamine can realize the rapid dyeing of hair, and the concentration of dopamine is more than 0.25 wt% so that the hair can be successfully dyed.

Example 17

Preparation of Fe²⁺Ion concentration of 5X 10^-3Adding 0.1mol/L Tris-HCl buffer solution with pH value of 7 into the solution, and adding platinum color head with length of about 10cm and color number of 613Wetting hair, adding dopamine into the solution to enable the concentration of the dopamine in the solution to be 0.5 wt%, stirring for 15 minutes, taking out the hair, washing the hair with deionized water, and naturally drying the hair.

Repeatedly washing the dyed hair with shampoo for 5, 10, 15, 20, 25, and 30 times.

Photographs of hair after dyeing and before and after washing for various times are shown in fig. 21, and fig. 21 shows the effect of the number of washes on the dyeing effect.

As shown in FIG. 21, the color of each dyed hair after washing was substantially unchanged from that before washing, and the results showed that Fe was used²⁺The oxidative polymerization of dopamine is catalyzed by ions, the hair can be quickly dyed, and the dyed hair has better color fastness after polydopamine dyeing.

The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present invention, and it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements and the like within the spirit and scope of the present invention should be included.

Industrial applicability

The oxidative polymerization of dopamine is carried out by the method provided by the invention, the rapid oxidative polymerization of dopamine can be realized while the advantages of simple and mild reaction conditions are kept, and particularly, the instantaneous polymerization can be realized under weak acidic and neutral conditions. The method provided by the invention can be advantageously used for surface modification of materials to be modified, has beneficial technical effects particularly on aspects of fabric dyeing, hair dyeing and the like, can realize quick completion of dyeing and dyeing under simple and mild conditions, and has excellent color fastness.

Claims

1. A method of oxidative polymerization of dopamine, comprising the steps of:

preparing a buffer solution with a pH value of more than 4;

2. The oxidative polymerization process of claim 1, wherein only atmospheric oxygen is used as the oxidant in the addition of dopamine to polymerize polydopamine.

3. Use of polydopamine for surface modification, characterized in that polydopamine is obtained by the process of oxidative polymerization of dopamine according to claim 1 or 2.

4. Use according to claim 3, wherein the pH of the buffer solution is in the range of 4 to 8.

5. Use according to claim 3 or 4, wherein said comprises Fe²⁺The Fe in solution of ions²⁺The concentration of the ions is 10^-4To 10^-1In the range of mol/L.

6. Use according to claim 3 or 4, wherein with respect to said inclusion of Fe²⁺A solution of ions and a total mass of dopamine added, said mass percentage concentration of dopamine being in the range of 0.01 wt% to 4 wt%.

7. Use according to claim 3, wherein the surface modification comprises deposition of polydopamine on the surface of the modified material.

8. Use according to claim 3, wherein the surface modification comprises deposition of polydopamine on a fabric.

9. Use according to claim 3, wherein the surface modification comprises deposition of polydopamine on the hair.