CN108993847B

CN108993847B - Application of composite coating, anti-corrosion material and preparation method of anti-corrosion material

Info

Publication number: CN108993847B
Application number: CN201810804403.XA
Authority: CN
Inventors: 王彩旗; 崔含蕊; 赵建亮
Original assignee: University of Chinese Academy of Sciences
Current assignee: University of Chinese Academy of Sciences
Priority date: 2018-07-20
Filing date: 2018-07-20
Publication date: 2020-02-21
Anticipated expiration: 2038-07-20
Also published as: CN108993847A

Abstract

The invention relates to application of a composite coating, an anti-corrosion material and a preparation method thereof. The composite coating includes: the hydrophilic layer and the hydrophobic layer that contact, hydrophilic layer contains hydrophilic substance, the hydrophobic layer contains hydrophobic substance. The corrosion-resistant material comprises a substrate and a composite coating formed on the surface of the substrate. The composite coating can be applied to the field of corrosion prevention, cannot enable liquid to permeate, and can effectively play a role in corrosion prevention. Furthermore, the composite coating in the anticorrosive material provided by the invention does not allow liquid to permeate, and the liquid does not enter the composite coating and contact with the substrate to corrode the substrate, so that the anticorrosive effect can be effectively achieved.

Description

Application of composite coating, anti-corrosion material and preparation method of anti-corrosion material

Technical Field

The invention relates to an application of a composite coating, an anticorrosive material and a preparation method thereof, belonging to the field of chemical materials and application.

Background

Chemical materials (such as metal, plastic, etc.) are prone to corrosion under the action of the external environment, and therefore huge economic losses are caused. In order to inhibit corrosion of chemical materials, a common method of corrosion protection is coating with organic or inorganic coatings. Although these coatings provide some protection from chemical materials, they still have many problems in practical use. The presence of micro-porous defects in organic or inorganic coatings generally impairs the anti-corrosive effect of the coating, so that the service life of the chemical material is greatly reduced.

In recent years, according to the principle of bionics, people imitate the super-hydrophobic surface of lotus leaves in nature, and develop super-hydrophobic coatings to make up for the defects of the traditional coating preparation process. In practice, however, external stimuli can cause water droplets to penetrate along the groove gaps of the superhydrophobic coating. In case of corrosion, the penetration of water droplets would cause the destruction of the air layer mentioned in the Cassie model, and once the air layer disappears, the liquid would enter the coating to contact the substrate and corrode the substrate. Both conventional organic or inorganic coatings and superhydrophobic coatings therefore suffer from liquid penetration.

For example, magnesium is one of the metals that is extremely susceptible to corrosion. Although magnesium has the characteristics of light weight and no toxicity, and good mechanical properties, processability and degradability, it rapidly degrades in a corrosive aqueous solution to become the most hindrance to its application. Particularly in the medical field, after magnesium serving as an implant material is corroded, hydrogen is released to cause a local pH to sharply rise, the magnesium is prematurely failed, and even healing and severe necrosis of local tissues are influenced, so that the magnesium has a great influence on a human body.

Therefore, it is an urgent need to solve the technical problem of developing a method or product capable of effectively dredging liquid and preventing liquid from permeating, which can be applied in the field of corrosion prevention.

Disclosure of Invention

Problems to be solved by the invention

In view of the technical problems of the prior art corrosion protection materials and methods, such as: external stimulation can cause water drops to permeate along the gaps of the grooves of the super-hydrophobic coating; the presence of microporous defects in organic or inorganic coatings can impair the corrosion protection effect, leading to a considerable reduction in the service life of the chemical material, etc. The invention firstly provides an application of a composite coating in corrosion prevention.

Furthermore, the invention also provides an anticorrosive material which can not enable liquid to permeate and can effectively play a role in corrosion prevention.

Further, the invention also provides a preparation method of the anti-corrosion material.

Means for solving the problems

The invention provides the use of a composite coating for corrosion protection, the composite coating comprising: a hydrophilic layer and a hydrophobic layer in contact,

the hydrophilic layer contains a hydrophilic substance, and the hydrophobic layer contains a hydrophobic substance.

The application of the invention is characterized in that the surface and/or the interior of the composite coating layer is provided with a plurality of pore structures, and the average pore diameter of the pore structures is between 0.1 and 1000 nm.

According to the application of the invention, the surface of the composite coating layer has an irregular structure, and preferably, the irregular structure comprises at least one of a concave structure, a convex structure and a reticular structure.

The application of the invention is that the hydrophilic substance comprises one or the combination of more than two of polyacrylic acid, polyurethane, polydopamine and polyvinyl alcohol; the hydrophobic substance comprises an aliphatic polyester.

According to the application of the invention, the composite coating is formed on the surface of the substrate, the hydrophobic layer is in contact with the surface of the substrate, and the hydrophilic layer is arranged on the side, opposite to the substrate, of the hydrophobic layer.

The invention also provides an anti-corrosion material, which comprises a substrate and a composite coating formed on the surface of the substrate;

the composite coating is the composite coating of the invention.

According to the anticorrosive material of the present invention, the substrate is a surface-treated substrate; preferably, after the substrate is subjected to surface treatment, the surface of the substrate has a net structure; wherein the matrix comprises one or the combination of more than two of metal, ceramic, plastic and glass.

The invention also provides a method for producing the corrosion-resistant material according to the invention, comprising:

a material obtaining step: dissolving hydrophilic substances in a first solvent to obtain a hydrophilic material; dissolving a hydrophobic substance in a second solvent to obtain a hydrophobic material;

a forming step: enabling the hydrophilic material and the hydrophobic material to alternately form a composite coating on the surface of the substrate; preferably, in the hydrophobic material, the content of the hydrophobic substance is 0.1-10 wt%; in the hydrophilic material, the concentration of the hydrophilic substance is 0.1-20 mg/mL.

According to the production method of the present invention, the molding step includes:

contacting the hydrophobic material with the surface of the substrate and forming a hydrophobic layer;

superimposing the hydrophilic material on a side of the hydrophobic layer opposite the substrate.

According to the preparation method of the present invention, before the molding step, the method further comprises:

a step of subjecting the substrate to surface treatment;

preferably, the surface of the substrate is subjected to a modification treatment using a modifier.

According to the preparation method of the invention, the modifier comprises an acidic solution, preferably, the acidic solution comprises one or a combination of more than two of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid;

more preferably, the modifier further comprises an alcohol and/or an inorganic salt; preferably, the alcohols include ethanol and/or glycerol.

ADVANTAGEOUS EFFECTS OF INVENTION

The composite coating can be applied to the field of corrosion prevention, cannot enable liquid to permeate, and can effectively play a role in corrosion prevention.

Furthermore, the composite coating in the anticorrosive material provided by the invention does not allow liquid to permeate, and the liquid does not enter the composite coating and contact with the substrate to corrode the substrate, so that the anticorrosive effect can be effectively achieved.

Furthermore, the preparation method of the anti-corrosion material has the advantages of easily available raw materials, higher safety, easy molding, short processing time and high production efficiency, and is suitable for industrial large-scale production.

Drawings

Fig. 1 is a perspective view showing the structure of an anticorrosive material produced according to an embodiment of the present invention.

FIG. 2 shows electron micrographs of a corrosion-resistant material I and a corrosion-resistant material II according to the invention;

fig. 3 shows a schematic graph of the contact angle size of different materials of example 1 and example 2 of the present invention.

FIG. 4 shows a schematic corrosion profile at day 0 for different materials of example 1 and example 2 of the present invention;

FIG. 5 shows a schematic corrosion profile on day 1 for different materials of example 1 and example 2 of the present invention;

FIG. 6 shows a schematic corrosion profile at day 5 for different materials of example 1 and example 2 of the present invention;

FIG. 7 shows a schematic corrosion profile at day 12 for different materials of example 1 and example 2 of the present invention;

FIG. 8 shows a schematic corrosion profile on day 21 for the different materials of example 1 and example 2 of the present invention.

Description of the reference numerals

1: a substrate; 2: a composite coating; 21: a hydrophobic layer; 22: a hydrophilic layer.

Detailed Description

Various exemplary embodiments, features and aspects of the invention will be described in detail below. The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In other instances, methods, means, devices and steps which are well known to those skilled in the art have not been described in detail so as not to obscure the invention.

First embodiment

A first embodiment of the invention provides the use of a composite coating for corrosion protection. As shown in fig. 1, the composite coating 2 of the present invention may include: the hydrophilic layer 22 and the hydrophobic layer 21 in contact,

the hydrophilic layer 22 contains a hydrophilic substance, and the hydrophobic layer 21 contains a hydrophobic substance.

The composite coating 2 of the present invention may be a Janus film, which generally refers to a film structure having an asymmetric structure or property. The key to distinguish a Janus membrane from a general asymmetric membrane is whether the properties of the two sides of the membrane are "opposite", such as hydrophilicity/hydrophobicity or electropositivity/electronegativity, etc., while the simple structural or compositional asymmetry cannot be called a Janus membrane. In the present invention, the composite coating 2 has two sides with different properties, i.e., has a Janus structure, and can exert its functions at the same time. The composite coating 2 can prevent liquid from permeating under the combined action of hydrophobic acting force, static pressure and capillary force, thereby achieving the purpose of corrosion prevention.

In the present invention, the composite coating 2 can be prepared by two methods: asymmetric preparation and asymmetric decoration. Asymmetric fabrication is where the Janus structures are formed during film formation, while asymmetric decoration is through post-modification to obtain the Janus structures.

The asymmetric fabrication may be to fabricate each side of the composite coating 2, separately to obtain the asymmetric structure, and then bond the two asymmetric structures together to obtain the Janus structure. For example: the hydrophobic layer 21 and the hydrophilic layer 22 may be prepared by an electrospinning method; it is also possible to prepare the hydrophobic layer 21 and the hydrophilic layer 22 by sequentially filtering the hydrophilic substance and the hydrophobic substance onto the porous substrate; it is also possible to take advantage of the migration or phase separation of immiscible components in the film matrix and to blend hydrophilic and hydrophobic substances in the casting solution so that the Janus structure can be obtained during the formation of the composite coating 2.

In addition, the asymmetric decoration can be a single-sided decoration to obtain the Janus structure. For example: the composite coating 2 having a Janus structure can be obtained by photochemical modification, vapor deposition, wet preparation, and the like. The preparation method of the hydrophilic layer 22 and the hydrophobic layer 21 of the composite coating 2 is not particularly limited in the present invention, as long as the corresponding Janus structure having the hydrophilic layer 22 and the hydrophobic layer 21 can be obtained.

Further, the composite coating 2 of the present invention has a plurality of pore structures on the surface and/or inside thereof, and the average pore diameter of the pore structures is between 0.1 and 1000 nm. In the composite coating 2, the hydrophilic layer 22 and the hydrophobic layer 21 can be tightly combined together, so that the composite coating can effectively play a role in corrosion prevention.

In the present invention, the surface of the composite coating 2 may also have a plurality of irregular structures. The irregular structure may be, for example: at least one of a concave structure, a convex structure, a mesh structure, and the like.

< hydrophobic layer >

In the present invention, the water-repellent layer 21 contains a hydrophobic substance, and the hydrophobic substance may be a substance containing a hydrophobic group and having hydrophobicity, for example: may be a chemical substance containing a C10-C20 hydrocarbon group; a chemical substance which may be a hydrocarbon group containing an aryl group, an ester group, an ether group, an amine group, an amide group, or the like; chemical substances which may also be hydrocarbon groups containing double bonds; chemical substances containing ester groups and the like are also possible. Preferably, the hydrophobic substance may include aliphatic polyesters such as polycaprolactone, polyglycolide, polylactide, polyglycolide-lactide, and the like.

As shown in fig. 1, in the present invention, the water-repellent layer 21 may be brought into contact with the surface of the substrate 1, and the hydrophilic layer 22 may be provided on the side of the water-repellent layer 21 opposite to the substrate 1, so that the corrosion prevention performance can be further improved.

< hydrophilic layer >

In the present invention, the hydrophilic layer 22 contains a hydrophilic substance. The hydrophilic substance may be a substance containing a hydrophilic group and having hydrophilicity, such as: the chemical substance may contain a carboxyl group, a sulfonic acid group, a sulfuric acid group, a phosphoric acid group, an amino group, a quaternary ammonium group, an ether group, a hydroxyl group, or the like. Specifically, in the present invention, the hydrophilic substance may include one or a combination of two or more of polyacrylic acid, polyurethane, polydopamine, polyvinyl alcohol, and the like.

The composite coating 2 prevents liquid from permeating under the combined action of hydrophobic acting force, static pressure and capillary force, thereby achieving the purpose of corrosion prevention. The composite coating 2 does not allow liquid to permeate, and thus can effectively prevent corrosion.

Second embodiment

A second embodiment of the present invention provides an anticorrosive material comprising: a substrate 1 and a composite coating 2 formed on the surface of the substrate 1;

the composite coating 2 is the composite coating 2 in the first embodiment.

In general, in the present invention, the composite coating layer 2 may be directly formed on the surface of the substrate 1, thereby performing an anti-corrosion function. The composite coating 2 can also be prepared in advance and then arranged on the surface of the substrate 1, thereby playing a role of corrosion resistance.

The composite coating 2 in the anti-corrosion material prevents liquid from permeating under the combined action of hydrophobic acting force, static pressure and capillary force, thereby achieving the purpose of corrosion resistance. The composite coating 2 does not allow liquid to permeate, and the liquid does not enter the composite coating 2 and contact with the substrate 1 to corrode the substrate 1, so that the anti-corrosion effect can be effectively achieved.

< substrate >

In the present invention, the composite coating 2 may be formed on the surface of the substrate 1, wherein the substrate 1 includes one or a combination of two or more of metal, ceramic, plastic and glass. The metal may be any one of gold, silver, copper, magnesium, iron, aluminum, and the like. The plastic may be polyethylene, polypropylene, etc.

In the present invention, the substrate 1 is preferably a surface-treated substrate. The surface treatment of the substrate 1 may be performed by physical, chemical, or the like; the substrate 1 is preferably surface-treated by chemical means. For example, the substrate 1 may be surface-treated with a modifier. After the surface treatment, the surface of the substrate 1 can have a net structure, so that the substrate can be better integrated with the composite coating 2.

In the present invention, the water-repellent layer 21 may be brought into contact with the surface of the substrate 1, and the hydrophilic layer 22 may be provided on the side of the water-repellent layer 21 opposite to the substrate 1, whereby the corrosion resistance can be further improved.

The composite coating layer 2 in the anticorrosive material of the present invention has not only excellent anticorrosive performance but also excellent biodegradability and adhesiveness, and can proliferate cells when implanted into a living body.

Third embodiment

A third embodiment of the present invention provides a method for producing the anticorrosive material of the second embodiment of the present invention, comprising:

a material obtaining step: dissolving a hydrophobic substance in a first solvent to obtain a hydrophobic material; dissolving hydrophilic substances in a second solvent to obtain hydrophilic materials;

a forming step: forming a composite coating 2 on the surface of the substrate 1 by the hydrophilic material and the hydrophobic material alternately; preferably, the first and second electrodes are formed of a metal,

the surface and/or the inside of the composite coating 2 may have a plurality of pore structures having an average pore diameter of 0.1 to 1000 nm.

In this embodiment, the first solvent is a solvent that can dissolve or partially dissolve the hydrophobic substance, for example: may be dichloromethane, trichloromethane, benzene, tetrahydrofuran, etc. The second solvent is a solvent that can dissolve or partially dissolve the hydrophilic substance, such as: alcohols, water, etc. may be used.

In the present embodiment, the alternating formation of the composite coating 2 may be to form a hydrophilic layer 22 on the surface of the substrate 1 by using a hydrophilic material, and then to overlap a hydrophobic material on the opposite side of the hydrophilic layer 22 from the substrate 1; it is also possible to form the hydrophobic layer 21 on the surface of the substrate 1 using a hydrophobic material and then to apply a hydrophilic material to the side of the hydrophobic layer 21 opposite to the substrate 1.

Generally speaking, the content of the hydrophobic substance in the hydrophobic material is 0.1-10 wt%; in the hydrophilic material, the concentration of the hydrophilic substance is 0.1-20 mg/mL. In the hydrophilic material, a pH adjuster may be used to adjust the pH to be alkaline, and the pH adjuster may be NaOH or the like.

In this embodiment, the molding step may include: bringing a hydrophobic material into contact with the surface of the substrate 1 to form a hydrophobic layer 21; a hydrophilic material is superimposed on the hydrophobic layer 21 on the side opposite to the substrate 1. By bringing the water-repellent layer 21 into contact with the surface of the substrate 1, the corrosion resistance can be further improved. The forming process can be one or a combination of more than two of spreading, coating, soaking, casting and spraying.

Before the molding step, the method further comprises the following steps: a step of surface-treating the substrate 1; by surface-treating the substrate 1, the composite coating 2 can be more firmly present on the surface of the substrate 1.

Preferably, the surface of the substrate 1 is subjected to a modification treatment with a modifier. The modifier comprises an acidic solution, preferably, the acidic solution comprises one or a combination of more than two of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid. In the present embodiment, the modifier may be a mixed solution containing an acidic solution, for example: alcohols (e.g., ethanol, glycerol, etc.) and inorganic salts may also be contained.

In general, the inorganic salts used may be chosen in accordance with the corrosion protection materials, in order not to introduce other impurities, such as: when Mg metal is used as a matrix and modification is performed with nitric acid, Mg (NO) may be selected₃)₂As an inorganic salt component.

Examples

Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

Example 1

(1) Cutting the magnesium ingot into a sample with the length of 1cm, the width of 1cm and the thickness of 0.2 cm; and respectively polishing and smoothing by using 200cw, 1000cw, 3000cw and 5000cw sand paper to obtain matrix Mg which is marked as Mg.

(2) Preparing modifier, HNO in aqueous solution of modifier₃Has a concentration of 22g/L, Mg (NO)₃)₂The concentration of (2) is 150g/L, and the concentration of ethanol is 300 g/L. Then the matrix is soaked in the aqueous solution of the modifier for 10s and then taken out, washed by distilled water and dried at room temperature to obtain modified matrix Mg, which is recorded as Mg-H.

(3) Preparing 2mg/mL polydopamine ethanol solution, and adjusting the pH value to 10 by using sodium hydroxide to obtain a hydrophilic material; preparing 2.5 wt% of a dichloromethane solution of polycaprolactone to obtain the hydrophobic material.

(4) And soaking the modified matrix Mg (Mg-H) in the hydrophilic material for 12H, and drying to obtain the anticorrosive material which is only provided with the hydrophilic layer and is marked as Mg-H-PDA.

(5) Soaking the anti-corrosion material (Mg-H-PDA) only provided with the hydrophilic layer in the hydrophobic material for 45s, and drying to obtain the anti-corrosion material I, namely Mg-H-PDA-PCL, wherein an electron microscope picture is shown in figure 2 (left), and the surface of the anti-corrosion material I has an irregular structure.

Example 2

Step (1) to step (3) of example 1 are the same as example 1, and example 2 differs from example 1 only in that: the sequence of the step (4) and the step (5) is interchanged, and the method specifically comprises the following steps:

(4) and (3) soaking the modified matrix (Mg-H) in a hydrophobic material for 45s, and drying to obtain the anticorrosive material only provided with the hydrophobic layer, which is named as Mg-H-PCL.

(5) Soaking the anti-corrosion material (Mg-H-PCL) only provided with the hydrophobic layer in the hydrophilic material for 12H, and drying to obtain the anti-corrosion material II, namely Mg-H-PCL-PDA, wherein an electron microscope picture is shown in figure 2 (right), and the surface of the anti-corrosion material II has an irregular structure.

Example 3

(1) Cutting the copper mesh into a sample with the length of 3cm and the width of 3cm to obtain a matrix Cu which is recorded as Cu;

(2) preparing 2mg/mL polydopamine ethanol solution, and adjusting the pH value to 10 by using sodium hydroxide to obtain a hydrophilic material; preparing 2.5 wt% of a dichloromethane solution of polycaprolactone to obtain the hydrophobic material.

(3) And soaking the substrate Cu in the hydrophobic material for 45s, and drying to obtain the anti-corrosion material only provided with the hydrophobic layer, which is named as Cu-PCL.

(4) And soaking the matrix Cu in the hydrophilic material for 12h, and drying to obtain the anticorrosive material which is only provided with the hydrophilic layer and is marked as Cu-PDA.

(5) The hydrophilic layer of the corrosion protection material (Cu-PDA) provided with only the hydrophilic layer is bonded above the hydrophobic layer of the corrosion protection material (Cu-PCL) provided with only the hydrophobic layer, so as to obtain the corrosion protection material III, which is named as Cu-PCL-PDA-Cu', of the invention.

Performance testing

Contact Angle testing

Respectively dripping water drops on the surfaces of samples to be detected of a matrix Mg (Mg), a modified matrix Mg (Mg-H), an anti-corrosion material (Mg-H-PCL) only provided with a hydrophobic layer, an anti-corrosion material (Mg-H-PDA) only provided with a hydrophilic layer, an anti-corrosion material I (Mg-H-PDA-PCL) and an anti-corrosion material II (Mg-H-PCL-PDA), and measuring the sizes of contact angles of the samples to be detected, wherein the sizes are shown in the following table 1 and figure 3:

TABLE 1

Test items	Contact Angle/°
		Mg	58.7
Mg-H	24.4
		Mg-H-PCL	90.7
Mg-H-PDA	47.4
		Mg-H-PDA-PCL	104.1
Mg-H-PCL-PDA	45.3

As can be seen from table 1 and fig. 3, Polycaprolactone (PCL) is hydrophobic, while Polydopamine (PDA) is hydrophilic. And Polycaprolactone (PCL) and Polydopamine (PDA) can be coated on the surface of the matrix magnesium.

Surface corrosion Performance test

Taking a matrix Mg (Mg), a modified matrix Mg (Mg-H), an anti-corrosion material (Mg-H-PCL) only provided with a hydrophobic layer, an anti-corrosion material (Mg-H-PDA) only provided with a hydrophilic layer, an anti-corrosion material I (Mg-H-PDA-PCL) and an anti-corrosion material II (Mg-H-PCL-PDA) as samples to be detected, scratching the surfaces of the samples to be detected, soaking the samples in SBF simulated body fluid at 37 +/-0.5 ℃ for 0 day, 1 day, 5 days and 12 days, taking out the samples after 21 days, and observing the corrosion degree near the scratches under an optical microscope, wherein the results are shown in figures 4-8.

As can be seen from fig. 4, all materials were not corroded at day 0.

As can be seen from FIG. 5, on day 1, the matrix Mg (Mg) and the modified matrix Mg (Mg-H) were significantly corroded; the corroded area of the anti-corrosion material (Mg-H-PCL) only provided with the hydrophobic layer is less than that of the anti-corrosion material (Mg-H-PDA) only provided with the hydrophilic layer; the anti-corrosion material I (Mg-H-PDA-PCL) only slightly corrodes near the scratch, the surface of the anti-corrosion material I is relatively complete, and the corroded area is less than that of the anti-corrosion material (Mg-H-PCL) only provided with the hydrophobic layer; the corrosion-resistant material II (Mg-H-PCL-PDA) has substantially no corroded area.

As can be seen from fig. 6, at day 5, the corrosion of the matrix Mg (Mg) and the modified matrix Mg (Mg-H) was increased, and the surface was piled up by corrosion products; the corrosion of the anti-corrosion material provided with only a hydrophobic layer (Mg-H-PCL) and the anti-corrosion material provided with only a hydrophilic layer (Mg-H-PDA) was intensified, but a relatively intact area could still be observed; the corroded area of the anti-corrosion material I (Mg-H-PDA-PCL) is less than that of an anti-corrosion material (Mg-H-PCL) only provided with a hydrophobic layer and that of an anti-corrosion material (Mg-H-PDA) only provided with a hydrophilic layer; the corrosion-resistant material II (Mg-H-PCL-PDA) had very few areas corroded, and the composite coating layer in the vicinity of the scratch was still observed.

As can be seen from FIG. 7, at day 12, the matrix Mg (Mg) and the modified matrix Mg (Mg-H) had corroded substantially completely; the corrosion of the anti-corrosion material (Mg-H-PCL) only provided with the hydrophobic layer and the corrosion-resistant material (Mg-H-PDA) only provided with the hydrophilic layer is intensified, and corrosion products are accumulated on the surface; the surface of the anti-corrosion material I (Mg-H-PDA-PCL) still has complete areas, and corrosion products are few; the surface of the anti-corrosion material II (Mg-H-PCL-PDA) is still intact, and no obvious corroded area exists.

As can be seen from FIG. 8, at 21 days, only a small amount of the area of the corrosion-resistant material II (Mg-H-PCL-PDA) was corroded, while the surface of the other corrosion-resistant material was substantially completely accumulated with the corrosion product.

Permeability test

A permeability test was performed using a substrate Cu (Cu), an anticorrosive material (Cu-PCL) provided with only a hydrophobic layer, an anticorrosive material (Cu-PDA) provided with only a hydrophilic layer, and an anticorrosive material III (Cu-PCL-PDA-Cu') of the present invention. The method specifically comprises the following steps:

a substrate Cu (Cu), an anti-corrosion material (Cu-PCL) only provided with a hydrophobic layer, an anti-corrosion material (Cu-PDA) only provided with a hydrophilic layer and an anti-corrosion material III (Cu-PCL-PDA-Cu') of the invention are used as samples to be detected, and the samples are fixed between two syringes by a clamp and are vertically placed. The height of the amount of water in the upper syringe when the water was dropped into the syringe and the water was observed to permeate from the upper syringe to the lower syringe was as shown in Table 2 below.

TABLE 2

Test items	Height of water amount/cm
		Cu	0
Cu-PDA	0
		Cu-PCL	3.2cm
Cu-PCL-PDA-Cu’	>7.5cm

As can be seen from table 2, the substrate Cu (Cu), the corrosion-resistant material (Cu-PDA) provided with only the hydrophilic layer, did not have water-retaining ability, and water easily permeated; the anti-corrosion material (Cu-PCL) only provided with the hydrophobic layer has certain water storage capacity, and water is not easy to permeate; the water storage capacity of the anti-corrosion material III (Cu-PCL-PDA-Cu') is better than that of an anti-corrosion material (Cu-PCL) only provided with a hydrophobic layer, and water cannot permeate through the anti-corrosion material III. It is thus clear that the anticorrosive material of the present invention has excellent permeation preventive properties and further excellent anticorrosive properties.

The above examples of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Use of a composite coating for corrosion protection, the composite coating comprising: a hydrophilic layer and a hydrophobic layer in contact,

the hydrophilic layer contains hydrophilic substances, and the hydrophobic layer contains hydrophobic substances;

the composite coating is formed on the surface of a substrate, the hydrophobic layer is in contact with the surface of the substrate, the hydrophilic layer is arranged on the side, opposite to the substrate, of the hydrophobic layer, and the surface of the composite coating is provided with an irregular structure, wherein the irregular structure comprises at least one of a concave structure, a convex structure and a reticular structure;

the hydrophobic substance comprises an aliphatic polyester;

the hydrophilic substance comprises one or the combination of more than two of polyacrylic acid, polyurethane, polydopamine and polyvinyl alcohol.

2. The use according to claim 1, wherein the composite coating has a plurality of pore structures on the surface and/or inside, the pore structures having an average pore size between 0.1 and 1000 nm.

3. An anticorrosion material, characterized in that the anticorrosion material comprises a substrate and a composite coating formed on the surface of the substrate;

the composite coating includes: a hydrophilic layer and a hydrophobic layer in contact,

the hydrophobic substance comprises an aliphatic polyester; the hydrophilic substance comprises polydopamine.

4. The anti-corrosion material according to claim 3, wherein the surface and/or the inside of the composite coating layer has a plurality of pore structures, and the average pore diameter of the pore structures is between 0.1 and 1000 nm.

5. The anticorrosive material according to claim 3 or 4, wherein the substrate is a surface-treated substrate.

6. The anticorrosive material according to claim 5, wherein the surface of the substrate after the surface treatment has a network structure; wherein the matrix comprises one or the combination of more than two of metal, ceramic, plastic and glass.

7. A method for producing an anti-corrosion material according to any one of claims 3 to 6, characterized by comprising:

a forming step: and (3) enabling the hydrophilic material and the hydrophobic material to alternately form a composite coating on the surface of the substrate.

8. The preparation method according to claim 7, wherein the content of the hydrophobic substance in the hydrophobic material is 0.1-10 wt%; in the hydrophilic material, the concentration of the hydrophilic substance is 0.1-20 mg/mL.

9. The method of manufacturing according to claim 8, wherein the molding step includes:

10. The production method according to any one of claims 7 to 9, characterized by further comprising, before the molding step:

and performing surface treatment on the substrate.

11. The production method according to claim 10, wherein the surface of the substrate is subjected to a modification treatment with a modifier.

12. The method of claim 11, wherein the modifier comprises an acidic solution.

13. The method according to claim 12, wherein the acidic solution includes one or a combination of two or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid.

14. The method according to claim 12 or 13, wherein the modifier further comprises an alcohol and/or an inorganic salt.

15. The method of claim 14, wherein the alcohol comprises ethanol and/or glycerol.