CN118185070B

CN118185070B - Super-slippery double-network hydrogel based on inhibition effect and preparation method and application thereof

Info

Publication number: CN118185070B
Application number: CN202410327126.3A
Authority: CN
Inventors: 刘宇宏; 王军宇; 许焱
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2024-03-21
Filing date: 2024-03-21
Publication date: 2025-02-07
Anticipated expiration: 2044-03-21
Also published as: CN118185070A

Abstract

The present application discloses a super-slippery double network hydrogel based on the inhibitory effect, and a preparation method and application thereof, wherein the preparation method of the super-slippery double network hydrogel based on the inhibitory effect comprises: subjecting a first precursor solution to a first ultraviolet irradiation in a first mold to obtain a first layer of network hydrogel; subjecting the first layer of network hydrogel to a first swelling in a second precursor solution to obtain an intermediate; subjecting the intermediate to a second ultraviolet irradiation in a second mold to obtain a second layer of network hydrogel; the first mold and the second mold are both molds with at least partial oxygen isolation function. The preparation method of the super-slippery double network hydrogel based on the inhibitory effect of the present application adopts a mold that has at least partial oxygen isolation function and performs two ultraviolet irradiations during the preparation process of the hydrogel, and utilizes the inhibitory effect of oxygen to reduce the friction coefficient of the hydrogel and improve the lubrication performance of the hydrogel.

Description

Super-smooth double-network hydrogel based on inhibition effect and preparation method and application thereof

Technical Field

The application relates to the technical field of high polymer materials, in particular to an ultra-smooth double-network hydrogel based on an inhibition effect, and a preparation method and application thereof.

Background

Hydrogels are flexible materials composed of crosslinked polymer networks containing large amounts of water, and are widely used in biomedical, soft robotic, and agricultural fields. When hydrogels and other material surfaces undergo interactions, excellent lubrication properties are critical, which have unique advantages in some areas, most typically in artificial articular cartilage. With aging population and increasing obesity rate, osteoarthritis has become an increasingly serious global health problem, and artificial joint replacement for treating severe arthritis is more frequent, so that hydrogel has become more important as an excellent candidate material for artificial joint cartilage, and lubrication performance has become one of the cores of hydrogel in practical application.

Various methods have been developed to improve the lubricating properties of hydrogels, such as lowering the friction coefficient based on the boundary layer formed by liposomes (CN 115569235B, a method for preparing hydrogels based on lipid lubrication), and permanent lubrication by forming a lubricating layer with functional molecules containing lubricating properties (CN 116854940a, a permanent lubrication hydrogel and a method for preparing the same). These methods reduce the coefficient of friction of hydrogels, but the absolute value of the coefficient of friction of hydrogels still has a large gap compared to natural articular cartilage and the friction experiment time is very short.

Therefore, how to effectively reduce the friction coefficient of the hydrogel is of great significance for improving the lubricating property of the hydrogel.

Disclosure of Invention

In view of the above, the present application aims to provide a preparation method of a super-smooth dual-network hydrogel based on an inhibition effect, in which a mold having at least partial isolation effect on oxygen is used and two times of ultraviolet irradiation are performed in the preparation process of the hydrogel, and the inhibition effect of oxygen is used to reduce the friction coefficient of the hydrogel and improve the lubrication performance of the hydrogel.

It is another object of the present application to provide a super-slippery dual-network hydrogel based on inhibition effect.

It is a further object of the present application to provide the use of a super-slippery dual-network hydrogel based on an inhibitory effect.

To achieve the above object, a first aspect of the present application provides a method for preparing a super-slippery dual-network hydrogel based on an inhibition effect, comprising:

carrying out first ultraviolet irradiation on the first precursor solution in a first die to obtain a first layer of network hydrogel;

Carrying out first swelling on the first layer of network hydrogel in a second precursor solution to obtain an intermediate;

carrying out second ultraviolet irradiation on the intermediate in a second die to obtain a second layer of network hydrogel;

the first mold and the second mold are both molds with at least partial oxygen isolation function.

In some embodiments, the materials of the first mold and the second mold each comprise at least one of glass, polymethyl methacrylate, polystyrene, and polycarbonate.

In some embodiments, the first precursor solution includes a first monomer, a first crosslinker, a first photoinitiator.

In some embodiments, the second precursor solution includes a second monomer, a second crosslinker, and a second photoinitiator.

In some embodiments, the material of the first mold is a material having a function of completely isolating oxygen, and the material of the second mold is a material allowing oxygen to pass through.

Preferably, the first mold is made of glass, and the second mold is made of polymethyl methacrylate.

In some embodiments, the first monomer comprises at least one of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, methacrylamide, sodium acrylate, 2-hydroxyethyl methacrylate.

In some embodiments, the first and second crosslinking agents each comprise at least one of N, N' -methylenebisacrylamide, ethylene glycol dimethacrylate.

In some embodiments, the first photoinitiator and the second photoinitiator each comprise at least one of a lithium phenyl (2, 4, 6-trimethylbenzoyl) phosphate salt, a photoinitiator 2959.

In some embodiments, the mass ratio of the first monomer, the first crosslinking agent, and the first photoinitiator is (15-22): 0.1-1): 0.01-0.03.

In some embodiments, the second monomer comprises at least one of acrylic acid, methacrylic acid.

In some embodiments, the mass ratio of the second monomer, the second crosslinking agent, and the second photoinitiator is (10-14): 0.05-0.2): 0.01-0.03.

In some embodiments, the material of the first mold is a material having a function of completely isolating oxygen, and the material of the second mold is a material having a function of at least partially isolating oxygen.

In some embodiments, the first mold and the second mold are both glass.

In some embodiments, ferric ions are contained in the second precursor solution or in the second precursor solution and the first precursor solution.

In some embodiments, the ferric ion concentration in the second precursor solution or the second precursor solution and the first precursor solution is 0.001-0.9mmol/L.

In some embodiments, the wavelength of the ultraviolet light is 350-370nm and the time of the ultraviolet light is 1-5h in the first ultraviolet light and the second ultraviolet light.

In some embodiments, the preparation method of the ultra-smooth dual-network hydrogel based on the inhibition effect further comprises a step of performing a second swelling of the intermediate product obtained after the second ultraviolet irradiation in pure water.

In some embodiments, the first swelling time is 40-56 hours.

In some embodiments, the second swelling time is 40-56 hours.

In some embodiments, the intermediate product obtained after the second ultraviolet irradiation is subjected to the second swelling in pure water, and the pure water is replaced every 10 to 12 hours.

The second aspect of the application provides a super-smooth double-network hydrogel based on an inhibition effect, which is prepared by adopting the preparation method of the super-smooth double-network hydrogel based on the inhibition effect.

In some embodiments, the inhibitory effect-based super-slip dual-network hydrogel comprises the first layer of network hydrogel and a second layer of network hydrogel, wherein the second layer of network hydrogel is coated on at least part of the outer surface layer of the first layer of network hydrogel.

In some embodiments, the inhibitory effect-based ultraslip dual network hydrogel has a coefficient of friction of 0.00383 to 0.01.

The third aspect of the application relates to application of the ultra-smooth double-network hydrogel based on the inhibition effect in the fields of cartilage repair, soft robots, medical instrument surface lubrication and the like.

The preparation method of the ultra-smooth double-network hydrogel based on the inhibition effect provided by the application has at least the following beneficial effects:

1. In the preparation process of the hydrogel, a die with at least partial isolation effect on oxygen is adopted and ultraviolet irradiation is carried out twice, so that the friction coefficient of the hydrogel can be reduced by utilizing the inhibition effect of the oxygen, and the lubricating property of the hydrogel is improved.

2. The ferric iron serving as an inhibitor is introduced into the second hydrogel to participate in the polymerization reaction of the hydrogel, and acts on free radicals generated by the second initiator, and meanwhile, a first die with an oxygen isolation function and a second die with at least partial oxygen isolation function are used, so that a better inhibition effect can be realized, the friction coefficient of the hydrogel is obviously reduced, the minimum friction coefficient of the hydrogel can reach 0.00383, and the friction coefficient of the hydrogel can still be kept at 0.0072 even after 6 hours of continuous friction.

Additional aspects and advantages of the application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and may be better understood from the following description of embodiments with reference to the accompanying drawings,

Wherein:

FIG. 1 is a schematic diagram of the preparation method of a super-smooth dual-network hydrogel based on an inhibition effect according to an exemplary embodiment of the present application.

FIG. 2 is a synthetic schematic diagram of a method for preparing a super-slippery dual-network hydrogel based on an inhibitory effect according to another exemplary embodiment of the present application.

Fig. 3 is a schematic diagram of a first mold and a second mold according to an exemplary embodiment of the present application, wherein a is a design frame diagram, b is a physical diagram before combination, c is a schematic diagram after combination, and d is a schematic diagram of a violet dye.

FIG. 4 is a graph showing the effect of oxygen inhibition on the friction coefficient of hydrogels, wherein Glass-PMMA-Gel, glass-Gel, PMMA-PMMA-Gel, PMMA-Glass-Gel represent the hydrogels prepared in example 8, example 1, example 9, and example 10, respectively.

FIG. 5 is a graph showing comparison of ferric ion inhibition of hydrogel polymerization at various concentrations.

FIG. 6 is a graph of the effect of ferric ion concentration on the coefficient of friction (i.e., a graph comparing the coefficient of friction of the hydrogels prepared in examples 1-7), wherein 0mM Fe³⁺、0.15mM Fe³⁺、0.3mM Fe³⁺、0.45mM Fe³⁺、0.6mM Fe³⁺、0.75mM Fe³ ⁺、0.9mM Fe³⁺ represents the hydrogels prepared in examples 1,2, 3,4, 5, 6, and 7, respectively.

FIG. 7 is a graph showing the effect of load and friction time on the friction performance of a hydrogel, wherein PMMA-Glass-Gel represents the hydrogel prepared in example 10, glass-PMMA-Gel represents the hydrogel prepared in example 8, DN-Hydrogel-0.3Fe ³⁺ represents the hydrogel prepared in example 3, the left graph a shows the effect of load change on the friction performance of the hydrogel, and the right graph b shows the effect of friction time change on the friction performance of the hydrogel.

FIG. 8 is a graph showing the change in friction coefficient with speed, wherein Glass-Gel represents the hydrogel prepared in comparative example 1 and PMMA-Gel represents the hydrogel prepared in comparative example 2.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present application and should not be construed as limiting the application.

In the present application, the disclosure of numerical ranges includes disclosure of all values and further sub-ranges within the entire range, including endpoints and sub-ranges given for these ranges.

In the present application, the materials and facilities involved are those which can be made by commercial means or known methods unless otherwise specified, and the methods involved are conventional methods unless otherwise specified.

The inventors found that the prior art method for improving the lubrication performance of hydrogels, although reducing the friction coefficient of hydrogels, the absolute value of the friction coefficient of hydrogels still has a large gap compared to natural articular cartilage, and the friction experiment time is very short. To solve this problem, the inventors have improved the lubrication performance of hydrogels based on the inhibition effect (strategy) in dual-network hydrogels (the mechanical properties of which are closer to practical applications). The friction coefficient of the hydrogel is greatly reduced, the lowest friction coefficient is very low, and the hydrogel still maintains excellent lubrication property after long-time continuous friction for 6 hours, which is very beneficial to practical application. Specifically, the idea of reducing the friction coefficient of the hydrogel based on the inhibition effect is that oxygen in air and ferric ions serving as efficient inhibitors are respectively utilized to realize the inhibition effect, so that the ultra-smooth double-network hydrogel is synthesized. Firstly, the method utilizes oxygen in air (figure 1) to synthesize the double-network hydrogel by using the first die and the second die, so that when the permeability of the first die and the second die to gas is changed, the oxygen permeation quantity in the hydrogel polymerization process can be regulated. Among the inhibitory effects of oxygen, it was found that the optimal frictional properties can be achieved by acting only on the second layer network hydrogel. Based on this experimental conclusion, the introduction of the highly effective inhibitor ferric ion further explores the potential of the inhibition effect to reduce the coefficient of friction.

The following describes a preparation method of the ultra-smooth double-network hydrogel based on the inhibition effect according to the embodiment of the application with reference to the accompanying drawings.

As shown in fig. 1, the preparation method of the ultra-smooth dual-network hydrogel based on the inhibition effect according to the embodiment of the application comprises the following steps:

S101, carrying out first ultraviolet irradiation on the first precursor solution in a first die to obtain a first layer of network hydrogel.

In the embodiment of the present application, in step S101, the purpose of the first ultraviolet irradiation is to generate free radicals by the photoinitiator through ultraviolet light, thereby forming free radical polymerization, and polymerizing the monomer into a high molecular polymer.

In some embodiments, the mass ratio of the first monomer, the first crosslinker, the first photoinitiator is (15-22): (0.1-1): (0.01-0.03), e.g., 18.2:0.6:0.02, etc.

As an alternative example, the first precursor solution may include water, except for the first monomer, the first crosslinking agent, and the first photoinitiator. The water may be ultrapure water, distilled water, or the like, for example.

In some embodiments, the first monomer includes, but is not limited to, at least one of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, methacrylamide, sodium acrylate, 2-hydroxyethyl methacrylate, and the like.

As an alternative example, the first monomer consists of acrylamide (AAm) and 2-acrylamido-2-methylpropanesulfonic Acid (AMPS).

As a non-limiting list, when the first monomer consists of acrylamide (AAm) and 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), the mass ratio of acrylamide (AAm) to 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) is (0.8-1.6): (12-22), including but not limited to 0.8:12, 0.8:22, 1.6:12, 1.6:22, or 1,2:1.7, etc.

In some embodiments, the mass fraction of the first monomer in the first precursor solution is 15-22%, including but not limited to 15%, 17%, 19%, 22%, etc.

In some embodiments, the first crosslinking agent includes, but is not limited to, at least one of N, N' -methylenebisacrylamide, ethylene glycol dimethacrylate, and the like.

In some embodiments, the mass fraction of the first crosslinker in the first precursor solution is 0.1-1%, including but not limited to 0.1%, 0.25%, 0.6%, 0.75%, or 1%, etc.

As an alternative example, the first crosslinking agent is N, N' -Methylenebisacrylamide (MBAA), and the mass fraction of the first crosslinking agent in the first precursor solution is 0.1%.

In some embodiments, the first photoinitiator includes at least one of lithium phenyl (2, 4, 6-trimethylbenzoyl) phosphate (LAP), and photoinitiator 2959.

In some embodiments, the mass fraction of the first photoinitiator in the first precursor solution is between 0.01 and 0.03%, including but not limited to 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, etc.

As an alternative example, the first photoinitiator is phenyl (2, 4, 6-trimethylbenzoyl) phosphate lithium salt, and the mass fraction of the first photoinitiator in the first precursor solution is 0.02%.

In some embodiments, the first mold is a mold having an at least partially oxygen barrier function.

It will be appreciated that the first die may be a die having a function of completely isolating oxygen, or may be a die having a function of partially isolating oxygen (i.e., at least partially passing oxygen).

It should be noted that, in the embodiment of the present application, the mold having the function of at least partially isolating oxygen may be implemented by a structure of the mold, or may be implemented by selecting a material of the mold.

In some embodiments, the material of the first mold includes, but is not limited to, at least one of glass, polymethyl methacrylate (PMMA), polystyrene, polycarbonate, and the like. Wherein:

when the material is glass, because glass is dense inorganic matter, can fine isolation oxygen, therefore first mould has the function of completely isolating oxygen.

When the material is polymethyl methacrylate (PMMA), PMMA is an organic substance formed by polymer chains, oxygen can relatively easily pass through PMMA, and free radicals generated in the polymerization process are restrained, so that the restraining effect is exerted, and therefore, the first die has the function of partially isolating oxygen (namely, at least partially passing oxygen).

In some embodiments, the wavelength of the ultraviolet light in the first ultraviolet radiation is 350-370nm, including but not limited to 350nm, 355nm, 360nm, 365nm, 370nm, etc.

In some embodiments, in the first ultraviolet irradiation, the period of ultraviolet irradiation is 1-5 hours, including but not limited to 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc.

S102, performing first swelling on the first layer of network hydrogel obtained in the step S101 in a second precursor solution to obtain an intermediate.

In some embodiments, the first layer of network hydrogel resulting from step S102 is swelled in a second precursor solution in order to allow the monomers, cross-linking agent and initiator in the second precursor solution to penetrate into the first layer of network hydrogel.

In some embodiments, the mass ratio of the second monomer, the second crosslinker, the second photoinitiator is (10-14): (0.05-0.2): (0.01-0.03), e.g., 12:0.1:0.02, etc.

As an alternative example, the second precursor solution may include water in addition to the second monomer, the second crosslinking agent, and the second photoinitiator. The water may be ultrapure water, distilled water, or the like, for example.

In the examples of the present application, the second monomer needs to satisfy two limitations, 1. Flexible polymer chains can be formed by free radical polymerization, 2. The second precursor solution needs to be acidic, otherwise ferric iron is easily hydrolyzed to form a colloid. Thus, in some cases the second monomer is acidic, such as acrylic acid, methacrylic acid, etc., and in other cases the second monomer is a non-acidic monomer, in which case additional acid is required to avoid ferric iron hydrolysis.

As an alternative example, the second monomer includes, but is not limited to, at least one of acrylic acid (AAc), methacrylic acid, and the like.

In some embodiments, the mass fraction of the second monomer in the second precursor solution is 10-14%, including but not limited to 10%, 11%, 12%, 13%, 14%, etc.

As an alternative example, the second monomer is acrylic acid, and the mass fraction of the second monomer in the second precursor solution is 0.1%.

In some embodiments, the second crosslinking agent includes, but is not limited to, at least one of N, N' -Methylenebisacrylamide (MBAA), ethylene glycol dimethacrylate, and the like.

In some embodiments, the mass fraction of the second crosslinker in the second precursor solution is 0.05-0.2%, including but not limited to 0.05%, 0.1%, 0.15%, or 0.2%, etc.

As an alternative example, the second crosslinking agent is N, N' -methylenebisacrylamide, and the mass fraction of the second crosslinking agent in the second precursor solution is 12%.

In some embodiments, the second photoinitiator includes, but is not limited to, at least one of lithium phenyl (2, 4, 6-trimethylbenzoyl) phosphate (LAP), photoinitiator 2959, and the like.

In some embodiments, the mass fraction of the second photoinitiator in the second precursor solution is between 0.01 and 0.03%, including but not limited to 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, etc.

As an alternative example, the second photoinitiator is phenyl (2, 4, 6-trimethylbenzoyl) phosphate lithium salt, and the mass fraction of the second photoinitiator in the second precursor solution is 0.02%.

In some embodiments, the first swelling time is 40-56h, including but not limited to 40h, 44h, 48h, 52h, 56h, or the like.

In some embodiments, the first swelling is performed in an air atmosphere.

In embodiments of the application, the first swelling is aimed at balancing the internal and external osmotic pressures of the hydrogel, while swelling significantly increases the volume of the hydrogel to facilitate the entry of the components of the second precursor solution into the hydrogel.

And S103, carrying out second ultraviolet irradiation on the intermediate obtained in the step S102 in a second die to obtain a second layer of network hydrogel (namely the final super-smooth double-network hydrogel based on the inhibition effect).

In the embodiment of the present application, in step S103, the purpose of the second ultraviolet irradiation is to generate free radicals by the photoinitiator through ultraviolet light, thereby forming free radical polymerization, and polymerizing the monomer into a high molecular polymer.

In some embodiments, the second mold is a mold having at least a partial oxygen barrier function.

It will be appreciated that the second die may be a die having a function of completely isolating oxygen, or may be a die having a function of partially isolating oxygen (i.e., at least partially passing oxygen).

In some embodiments, the material of the second mold includes, but is not limited to, at least one of glass, polymethyl methacrylate (PMMA), polystyrene, polycarbonate, and the like. Wherein:

when the material is glass, because glass is dense inorganic matter, can fine isolation oxygen, therefore the second mould has the function of completely isolating oxygen.

When the material is polymethyl methacrylate (PMMA), PMMA is an organic substance formed by polymer chains, oxygen can relatively easily pass through PMMA, and free radicals generated in the polymerization process are restrained, so that the restraining effect is exerted, and therefore, the second die has the function of partially isolating oxygen (namely, at least partially passing oxygen).

In some embodiments, the wavelength of the ultraviolet light in the second ultraviolet radiation is 350-370nm, including but not limited to 350nm, 355nm, 360nm, 365nm, 370nm, etc.

In some embodiments, the second ultraviolet irradiation is performed for a period of time ranging from 1 to 5 hours, including but not limited to 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc.

In some embodiments, the method for preparing a super-smooth dual-network hydrogel based on the inhibition effect further comprises a step of performing a second swelling of the intermediate product obtained after the second ultraviolet irradiation in pure water. The purpose of the second swelling is to remove unreacted monomers. It should be noted that, in the embodiment of the present application, since even a small amount of the residual first monomer is in the hydrogel, this portion of the first monomer still participates in the free radical polymerization during the second polymerization (i.e., the second uv irradiation), the second swelling-removed monomer is mainly the second monomer, and the first monomer may be present and in a small amount.

In some embodiments, the second swelling time is 40-56h, including but not limited to 40h, 44h, 48h, 52h, 56h, or the like.

In some embodiments, the second swelling is performed in an air atmosphere.

In some embodiments, the intermediate product obtained after the second ultraviolet irradiation is subjected to the second swelling in pure water, and the pure water is replaced every 10 to 12 hours (e.g., 10 hours, 11 hours, 12 hours, etc.). The purpose of this is to remove the unreacted monomers completely.

In some embodiments, as shown in fig. 2, the second precursor solution also contains ferric ions. In the embodiment of the application, the inhibitor ferric ion is added into the second precursor solution, the inhibitor ferric ion participates in the polymerization reaction of the second layer network hydrogel, and acts on the free radical generated by the second initiator, so that the inhibition effect can be exerted, and the friction coefficient is obviously reduced. The inhibition effect is mainly that a loose hydrogel network and a large number of polymer catenaries are formed by reducing covalent cross-linking of the hydrogel, so that shearing force in the friction process is reduced, and the friction coefficient of the hydrogel is further reduced.

In some embodiments, ferric ion can be derived from a variety of soluble ferric salts.

As a non-limiting list, soluble ferric salts include, but are not limited to, at least one of ferric nitrate, ferric chloride, ferric sulfate, and the like.

In the examples of the present application, the anions in the soluble ferric salt do not participate in the reaction, so that the salt capable of providing ferric ion can exert the inhibition effect and significantly reduce the friction coefficient. Meanwhile, since the object of the action of the ferric ion is a radical generated by the second initiator, the concentration of the ferric ion is in the same order as that of the second initiator.

In some embodiments, the concentration of ferric ion in the second precursor solution is 0.001 to 0.9mmol/L. In the embodiment of the application, the concentration of ferric ions in the second precursor solution is within the range, so that the friction coefficient of the hydrogel can be reduced, and when the concentration is lower than 0.001mmol/L, a remarkable effect can not be exerted, and when the concentration is higher than 0.9mmol/L, the friction coefficient of the hydrogel is increased.

It should be noted that, when the second precursor solution does not contain ferric ions, the preparation method of the ultra-smooth dual-network hydrogel based on the inhibition effect in the embodiment of the application only depends on the oxygen inhibition effect to reduce the friction coefficient. At this time, the inventors found that when the material of the first mold is a material having a function of completely isolating oxygen and the material of the second mold is a material allowing oxygen to pass, the ultra-smooth double-network hydrogel based on the inhibition effect obtained by the preparation method of the ultra-smooth double-network hydrogel based on the inhibition effect has the lowest friction coefficient, which means that the introduction of the inhibitor such as ferric ion into the second precursor solution alone can exert the best friction coefficient reducing effect.

Therefore, in some embodiments, when the second precursor solution does not contain ferric ions, and the method for preparing the ultra-smooth dual-network hydrogel based on the inhibition effect according to the embodiment of the present application only depends on the oxygen inhibition effect to reduce the friction coefficient (as shown in fig. 1), as a preferred example, the material of the first mold is a material having a function of completely isolating oxygen, and the material of the second mold is a material allowing oxygen to pass through. As a non-limiting example, the material of the first mold is Glass (Glass) or the like, and the material of the second mold is polymethyl methacrylate (PMMA) or the like.

As an alternative example, when the second precursor solution does not contain ferric ions, and the preparation method of the super-smooth dual-network hydrogel based on the inhibition effect according to the embodiment of the present application reduces the friction coefficient only by the oxygen inhibition effect, as shown in fig. 1, the preparation method of the super-smooth dual-network hydrogel based on the inhibition effect according to the embodiment of the present application includes:

The first precursor solution was poured into a first mold and irradiated with ultraviolet light at 365nm for 3 hours. And then taking out the reacted hydrogel from the first die, putting the hydrogel into the prepared second precursor solution, and swelling for 48 hours. The fully swollen hydrogel was removed and placed again in a second mold and irradiated with 365nm ultraviolet light for 3 hours. The reacted double network hydrogel was removed from the second mold, fully swelled in pure water for 48 hours, and the unreacted monomer was removed every 12 hours by changing the pure water. Wherein, the material of the first mould and the second mould is Glass (Glass) or polymethyl methacrylate (PMMA). Preferably, the first mold is made of Glass (Glass), and the second mold is made of polymethyl methacrylate (PMMA).

In other embodiments, when the second precursor solution contains ferric ions, the preparation method of the ultra-smooth dual-network hydrogel based on the inhibition effect of the embodiment of the present application relies on the inhibition effect of the inhibitor such as ferric ions or the inhibition effect of the inhibitor such as ferric ions and the oxygen inhibition effect to reduce the friction coefficient (as shown in fig. 2), the material of the first mold is a material with a function of completely isolating oxygen, and the material of the second mold is a material with a function of at least partially isolating oxygen.

As a non-limiting example, when the second precursor solution contains ferric ions and the preparation method of the ultra-smooth dual-network hydrogel based on the inhibition effect according to the embodiment of the present application only reduces the friction coefficient by the inhibition effect of the inhibitor such as ferric ions (as shown in fig. 2), in order to avoid the interference of oxygen in the air, the material of the first mold and the material of the second mold are both materials having a function of completely isolating oxygen, for example, glass (Glass).

As a non-limiting example, when the second precursor solution contains ferric ions and the preparation method of the ultra-smooth dual-network hydrogel based on the inhibition effect of the embodiment of the application relies on the inhibition effect of the inhibitor such as ferric ions and the oxygen inhibition effect to jointly reduce the friction coefficient (as shown in fig. 2), the material of the first mold is a material with a function of completely isolating oxygen, such as Glass (Glass), and the material of the second mold is a material allowing oxygen to pass through, but the oxygen passing rate of the second mold needs to be controlled to be smaller than that of the second mold which only relies on the oxygen inhibition effect to reduce the friction coefficient, so that the synergistic effect of the inhibition effect of the inhibitor such as ferric ions and the oxygen inhibition effect can ensure that a better friction coefficient reducing effect can be obtained.

As an alternative example, when the second precursor solution contains ferric ions, the preparation method of the super-smooth dual-network hydrogel based on the inhibition effect of the embodiment of the present application relies on the inhibition effect of the inhibitor such as ferric ions or the inhibition effect of the inhibitor such as ferric ions and the oxygen inhibition effect to reduce the friction coefficient, as shown in fig. 2, the preparation method of the super-smooth dual-network hydrogel based on the inhibition effect of the embodiment of the present application includes:

the first precursor solution was poured into the first mold and irradiated under ultraviolet light at 365nm for 3 hours. And then taking out the reacted hydrogel from the first die, putting the hydrogel into a prepared second precursor solution with ferric ion concentration ranging from 0.001 mmol/L to 0.9mmol/L, and swelling for 48 hours. The fully swollen hydrogel was removed and placed again in a second mold and irradiated with 365nm ultraviolet light for 3 hours. The reacted double network hydrogel was removed from the second mold, fully swelled in pure water for 48 hours, and the unreacted monomer was removed every 12 hours by changing pure water, and the resultant hydrogel was named DN-Hydrogel-XFe ³⁺, where X means the concentration of ferric ion was X mmol/L. Wherein, the material of the first mould and the second mould is Glass (Glass).

The first precursor solution and the second precursor solution without the inhibitor such as ferric ion of the present application may be other precursor solution compositions suitable for dual-network hydrogels, which are well known in the art, in addition to the compositions of the present application.

It should be further noted that, in the embodiment of the present application, the structures of the first mold and the second mold are not limited, and may be any mold that can make a dual-network hydrogel, for example, a mold as shown in fig. 3, which is well known in the art.

In some embodiments, the method of preparing an inhibitory effect-based ultra-smooth dual network hydrogel of embodiments of the present application further comprises the step of formulating a first precursor solution and a second precursor solution.

By way of non-limiting example, the first precursor solution may be prepared by dissolving the first monomer in water, followed by adding the first crosslinking agent and the first photoinitiator and mixing.

As a non-limiting list, when ferric ion is not contained in the second precursor solution, the second precursor solution is prepared by a method comprising dissolving the second monomer, the second crosslinking agent, and the second photoinitiator in water.

As a non-limiting list, when ferric ions are contained in the second precursor solution, the second precursor solution is prepared by dissolving the second monomer, the second crosslinking agent and the second photoinitiator in water, followed by adding ferric nitrate or the like, and the above-mentioned soluble ferric salts.

It should be noted that, in the embodiment of the present application, the step of preparing the first precursor solution precedes the step S101, the step of preparing the second precursor solution may precede the step S101, between the step S101 and the step S102, and when the step of preparing the first precursor solution and the step of preparing the second precursor solution precede the step S101, the sequence of the step of preparing the first precursor solution and the step of preparing the second precursor solution is not limited.

In addition, it should be noted that, in the embodiment of the present application, when ferric ions need to be introduced, on one hand, ferric ions may be introduced into the first-layer network hydrogel, but ferric ions cannot be introduced only into the first-layer network hydrogel, but not into the second-layer network hydrogel, and ferric ions are introduced into the first-layer network hydrogel, and the effect of ferric ions acts on both the first-layer network hydrogel and the second-layer network hydrogel. Specifically, ferric iron is added into the first layer of network hydrogel, and even ppm ferric iron is always present in the hydrogel, and although ferric iron is changed into ferrous iron after the polymerization reaction is completed, the first swelling (as described above, the first swelling process is performed in air) in step S102 is quickly oxidized into ferric iron again by oxygen in air, so that the second layer of network hydrogel functions. Alternatively, ferric ions may be introduced separately into the first layer of the network hydrogel as previously described. When ferric ions are simultaneously introduced into both the first layer of network hydrogel and the second layer of network hydrogel, ferric ions need to be added into the first precursor solution, and the material selection, concentration and the like of the specific ferric ions are the same as those of the case of adding ferric ions into the second precursor solution, and are not repeated herein.

The preparation method of the ultra-smooth double-network hydrogel based on the inhibition effect provided by the embodiment of the application has at least the following beneficial effects:

The super-smooth double-network hydrogel based on the inhibition effect is prepared by adopting the preparation method of the super-smooth double-network hydrogel based on the inhibition effect.

In some embodiments, the inhibitory effect-based super-slippery dual-network hydrogel of the embodiments of the present application comprises a first layer of network hydrogel and a second layer of network hydrogel, the second layer of network hydrogel coating at least a portion of the outer surface layer of the first layer of network hydrogel.

In some embodiments, the coefficient of friction of the ultra-smooth dual network hydrogels of embodiments of the present application based on the inhibition effect is 0.00383-0.01 (see example 3, infra, where best).

The ultra-smooth double-network hydrogel based on the inhibition effect can be widely applied to the fields of cartilage repair, soft robots, medical instrument surface lubrication and the like, and is used for reducing friction coefficient and improving lubrication effect.

Certain features of the present technology are further illustrated in the following non-limiting examples.

1. Examples and comparative examples

In each of the following examples and comparative examples, the first mold and the second mold were each a mold having a structure as shown in fig. 3.

Example 1 (Glass-Gel)

The preparation method of the ultra-smooth double-network hydrogel based on the inhibition effect comprises the following steps:

(1) The preparation of the first precursor solution comprises dissolving acrylamide (AAm) and 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) in ultrapure water, and then adding a crosslinking agent N, N' -Methylenebisacrylamide (MBAA) and a photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) to mix uniformly to obtain the first precursor solution.

Wherein, the mass fraction of the acrylamide (AAm) in the first precursor solution is 1.2 percent, the mass fraction of the 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) is 17 percent, the mass fraction of the first cross-linking agent N, N' -Methylenebisacrylamide (MBAA) is 0.6 percent, and the mass fraction of the first photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) is 0.02 percent based on the total mass of the first precursor solution.

(2) And (3) preparing the first layer of network hydrogel, namely placing the first precursor solution obtained in the step (1) into a first die, and irradiating for 3 hours under 365nm ultraviolet light to obtain the first layer of network hydrogel.

Wherein the first mold is a Glass (Glass) mold (i.e., the material of the first mold is Glass).

(3) And (3) preparing a second precursor solution, namely dissolving second monomer acrylic acid, a second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) and a second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) in ultrapure water to obtain the second precursor solution.

Wherein, the mass fraction of the second monomer acrylic acid in the second precursor solution is 12 percent, the mass fraction of the second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) is 0.1 percent, and the mass fraction of the second photoinitiator phenyl (2, 4, 6-trimethyl benzoyl) lithium phosphate (LAP) is 0.02 percent based on the total mass of the second precursor solution.

(4) And (3) preparing a second-layer network hydrogel, namely putting the first-layer network hydrogel obtained in the step (2) into the second precursor solution obtained in the step (3) to be soaked for 48 hours, so that the first-layer network hydrogel is fully swelled, and an intermediate is obtained. The intermediate was placed in a second mold, irradiated with 365nm uv light for 3 hours, then fully swelled in pure water for 48 hours, and after each 12 hour change of pure water, unreacted completed monomers were removed to obtain a second layer of network hydrogel (i.e., the ultra-smooth double network hydrogel based on the inhibitory effect of this example, labeled Glass-Gel).

Wherein the second mold is a Glass (Glass) mold (i.e., the material of the second mold is Glass).

Example 2

This embodiment is substantially the same as embodiment 1 except that:

The preparation method of the second precursor solution in the step (3) comprises the steps of dissolving second monomer acrylic acid, a second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) and a second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) in water, and then adding ferric nitrate to obtain the second precursor solution.

In the second precursor solution, the molar concentration of ferric ion was 0.15mM.

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as DN-Hydrogel-0.15Fe ³⁺.

Example 3

This embodiment is substantially the same as embodiment 2 except that:

in step (3), the molar concentration of ferric ion in the second precursor solution is 0.3mM.

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as DN-Hydrogel-0.3Fe ³ ⁺.

Example 4

This embodiment is substantially the same as embodiment 2 except that:

In step (3), the molar concentration of ferric ion in the second precursor solution is 0.45mM.

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as DN-Hydrogel-0.45Fe ³⁺.

Example 5

This embodiment is substantially the same as embodiment 2 except that:

In step (3), the molar concentration of ferric ion in the second precursor solution is 0.6mM.

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as DN-Hydrogel-0.6Fe ³ ⁺.

Example 6

This embodiment is substantially the same as embodiment 2 except that:

In step (3), the molar concentration of ferric ion in the second precursor solution is 0.75mM.

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as DN-Hydrogel-0.75Fe ³⁺.

Example 7

This embodiment is substantially the same as embodiment 2 except that:

In step (3), the molar concentration of ferric ion in the second precursor solution is 0.9mM.

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as DN-Hydrogel-0.9Fe ³ ⁺.

Example 8 (Glass-PMMA-Gel)

This embodiment is substantially the same as embodiment 1 except that:

In the step (2), the first mold is a Glass (Glass) mold (i.e., the material of the first mold is Glass), and in the step (4), the second mold is a polymethyl methacrylate (PMMA) mold (i.e., the material of the second mold is PMMA).

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as Glass-PMMA-Gel.

Example 9 (PMMA-PMMA-Gel)

This embodiment is substantially the same as embodiment 1 except that:

In the step (2), the first mold is a polymethyl methacrylate (PMMA) mold (i.e., the material of the first mold is PMMA), and in the step (4), the second mold is a polymethyl methacrylate (PMMA) mold (i.e., the material of the second mold is PMMA).

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as PMMA-PMMA-Gel.

Example 10 (PMMA-Glass-Gel)

This embodiment is substantially the same as embodiment 1 except that:

In the step (2), the first mold is a polymethyl methacrylate (PMMA) mold (i.e., the material of the first mold is PMMA), and in the step (4), the second mold is a Glass (Glass) mold (i.e., the material of the second mold is Glass).

The ultra-smooth double-network hydrogel based on the inhibition effect prepared in the embodiment is marked as PMMA-Glass-Gel.

Comparative example 1

This comparative example is substantially the same as example 1 except that:

step (3) is not required, i.e. the second precursor solution does not need to be provided.

And (4) fully swelling in pure water for 48 hours, and removing unreacted monomers after 12 hours of pure water replacement to obtain the final first layer of network hydrogel.

The hydrogel prepared in this comparative example was designated Glass-Gel.

Comparative example 2

This comparative example is substantially the same as example 9 except that:

The double network hydrogel prepared in this comparative example was labeled PMMA-Gel.

2. Friction test of hydrogel

The friction coefficients of the four hydrogels of example 1, examples 8-10 based on the oxygen inhibition effect were first tested. The experimental results are shown in FIG. 4. As can be seen from fig. 4, the change of the materials of the first mold and the second mold can significantly affect the friction coefficient of the hydrogel, and the difference between the friction coefficients of the hydrogel obtained by combining the first mold and the second mold with different materials can reach an order of magnitude, which fully illustrates that the inhibition effect of oxygen can effectively reduce the friction coefficient of the double-network hydrogel. Furthermore, because the networks of dual-network hydrogels have different network structures and chain lengths, the inhibition effect is not all positive to the effect of the different networks from the standpoint of reducing the coefficient of friction. From FIG. 4, it can be seen that Glass-PMMA-Gel (hydrogel prepared in example 8) has the lowest coefficient of friction.

In order to further exploit the potential of the inhibition effect to reduce the coefficient of friction, the present application selects a highly effective inhibitor, fe ³⁺. According to the experimental result of oxygen inhibition effect, we choose to add ferric ion with different concentration only in the second layer network hydrogel to realize the optimal friction coefficient reducing effect.

To verify that very small amounts of ferric ions can produce a significant inhibitory effect, we performed the following experiment (fig. 5):

Preparing four second precursor solutions with different ferric ion concentrations, namely a second precursor solution 1, a second precursor solution 2, a second precursor solution 3 and a second precursor solution 4, wherein the preparation methods are as follows:

The preparation method of the second precursor solution 1 comprises the steps of dissolving second monomer acrylic acid, a second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) and a second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) in water, and then adding ferric nitrate to obtain the second precursor solution 1. Wherein the mass fraction of the second monomer acrylic acid in the second precursor solution is 12%, the mass fraction of the second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) is 0.1%, the mass fraction of the second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) is 0.02%, and the molar concentration of ferric ions in the second precursor solution 1 is 0mM.

The preparation method of the second precursor solution 2 comprises the steps of dissolving second monomer acrylic acid, a second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) and a second photoinitiator phenyl (2, 4, 6-trimethyl benzoyl) lithium phosphate (LAP) in water, and then adding ferric nitrate to obtain a second precursor solution 1. Wherein the mass fraction of the second monomer acrylic acid in the second precursor solution is 12%, the mass fraction of the second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) is 0.1%, the mass fraction of the second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) is 0.02%, and the molar concentration of ferric ions in the second precursor solution 2 is 1mM.

The second precursor solution 3 is prepared by dissolving a second monomer acrylic acid, a second crosslinking agent N, N' -Methylenebisacrylamide (MBAA) and a second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) in water, and then adding ferric nitrate to obtain a second precursor solution 1. Wherein the mass fraction of the second monomer acrylic acid in the second precursor solution is 12%, the mass fraction of the second crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) is 0.1%, the mass fraction of the second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) is 0.02%, and the molar concentration of ferric ions in the second precursor solution 3 is 2mM.

The second precursor solution 4 is prepared by dissolving a second monomer acrylic acid, a second crosslinking agent N, N' -Methylenebisacrylamide (MBAA) and a second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) in water, and then adding ferric nitrate to obtain a second precursor solution 1. Wherein the mass fraction of the second monomer acrylic acid in the second precursor solution is 12%, the mass fraction of the second crosslinking agent N, N' -Methylenebisacrylamide (MBAA) is 0.1%, the mass fraction of the second photoinitiator phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate (LAP) is 0.02%, and the molar concentration of ferric ions in the second precursor solution 4 is 3mM.

The second precursor solution 1, the second precursor solution 2, the second precursor solution 3 and the second precursor solution 4 are respectively irradiated under 365nm ultraviolet for different time, wherein each second precursor solution is respectively irradiated for 2min, 4min, 6min and 8min, and the polymerization state change of the hydrogel is observed, and the result is shown in fig. 5. As can be seen from fig. 5, as the concentration of ferric ions increases, the time required for the hydrogel to polymerize from a liquid state to a solid state increases from the initial 2min to 8min, and this experimental result fully demonstrates that ferric ions can significantly inhibit the polymerization of the hydrogel.

Based on this experiment we tested the friction coefficients of hydrogels of examples 1-7 with different ferric ion concentrations by testing the friction coefficients of hydrogels prepared in examples 1-7 with different ferric ion concentrations, respectively, under a load of 1N. The test results are shown in fig. 6.

As can be seen from fig. 6, the friction coefficient of the hydrogel underwent a decrease followed by an increase with increasing ferric ion concentration. From the viewpoint of reducing the friction coefficient, the optimal ferric iron concentration is 0.3mmol/L. The reason why the friction coefficient of the hydrogel undergoes the descending section and the ascending section is that ferric ions have an inhibiting effect to reduce the friction coefficient, and can form weak physical cross-linking with carboxyl groups in the second-layer network hydrogel through electrostatic action, so that the physical cross-linking is greatly increased due to excessive ferric ions, the hydrogel grid is densified, and the friction coefficient is further increased. The experiment proves that the friction coefficient of the hydrogel can be effectively reduced by the inhibition effect on the prediction of the reduction friction coefficient of ferric ions, and the optimal ferric ion concentration is 0.3mmol/L and the lowest friction coefficient is 0.00383.

On the basis of the above experimental results, the application tested more careful friction properties of DN-Hydrogel-0.3Fe ³⁺ hydrogels prepared in example 3 by observing the change in the friction coefficient of the hydrogel during the increase of the load from 1N to 8N (FIG. 7 a) and the change in the friction coefficient of the hydrogel at a sliding speed of 1N for 6 hours (FIG. 7 b). The test results are shown in fig. 7.

The PMMA-Glass-Gel hydrogels prepared in example 10 and the Glass-PMMA-Gel hydrogels prepared in example 8 were selected for comparison with the DN-Hydrogel-0.3Fe ³⁺ hydrogels prepared in example 3, because PMMA-Glass-Gel and Glass-PMMA-Gel represent the worst and best two hydrogels, respectively, of the oxygen inhibition effects, symbolizing the upper and lower limits of the inhibition effect hydrogels. As can be seen from fig. 7, as the load increases, the difference in friction coefficients of the three hydrogels becomes smaller, but DN-Hydrogel-0.3Fe ³⁺ still has the lowest friction coefficient, illustrating the contribution of ferric ions as a high-efficiency inhibitor to the reduction of friction coefficient (fig. 7 a). The difference in friction performance was continuously amplified with increasing friction time, the initial lower friction coefficient was more excellent in the long-term friction experiment (fig. 7 b), the ultra-slip was maintained only by DN-Hydrogel-0.3Fe ³⁺ after the continuous friction for 3 hours (friction coefficient < 0.01), and furthermore, the friction coefficient of DN-Hydrogel-0.3Fe ³⁺ hydrogel prepared in example 3 was maintained at 0.0072 even after the continuous friction for 6 hours, and the friction coefficient was reduced by 94% with respect to PMMA-Glass-Gel hydrogel prepared in example 10. The experimental results further support that the high-efficiency inhibitor ferric iron can remarkably improve the friction performance of the hydrogel, and the friction coefficient of the hydrogel is excellent in both absolute value and relative value.

The present experiment further tested the trend of the friction coefficient with speed for comparative example 1 and comparative example 2, as shown in fig. 8, with a load of 1N. As can be seen from FIG. 8, the PMMA-Gel of comparative example 2 has a lower coefficient of friction than the Glass-Gel of comparative example 1, since PMMA-Gel is affected by the inhibitory effect during synthesis to form a relatively loose network structure, which is also consistent with previous theories. However, the absolute values of the friction coefficients of the comparative examples were substantially greater than 0.01, and the results were very poor with respect to the best example 3 (example 3 reduced the friction coefficients of comparative examples 1 and 2 by about 80% and 60%, respectively). This also demonstrates the advantage of selecting a dual network hydrogel that can achieve more excellent friction properties under the effect of the inhibition effect. Meanwhile, in combination with fig. 8 and 4, comparative example 1 and example 1 showed a relatively large decrease in the friction coefficient, indicating that the second layer of network hydrogel was effective in decreasing the friction coefficient when the second layer of network hydrogel was contained and both the first mold and the second mold were glass molds, and comparative example 2 and example 9 showed a relatively small decrease in the friction coefficient, indicating that the second layer of network hydrogel was helpful in decreasing the friction coefficient when the second layer of network hydrogel was contained and both the first mold and the second mold were PMMA molds, but the ability to decrease the friction coefficient was decreased.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.

Claims

1. The preparation method of the ultra-smooth double-network hydrogel based on the inhibition effect is characterized by comprising the following steps of:

the first die and the second die are dies with at least partial oxygen isolation function, wherein the first precursor solution comprises a first monomer, a first crosslinking agent and a first photoinitiator, the second precursor solution comprises a second monomer, a second crosslinking agent and a second photoinitiator, the first monomer comprises at least one of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, methacrylamide, sodium acrylate and 2-hydroxyethyl methacrylate, and the second monomer comprises at least one of acrylic acid and methacrylic acid;

The second precursor solution or the second precursor solution and the first precursor solution contain ferric ions;

The concentration of ferric ions in the second precursor solution or the second precursor solution and the first precursor solution is 0.15-0.6mmol/L, and the concentration of ferric ions is in the same magnitude as the concentration of the second photoinitiator;

The first mold is made of glass, and the second mold is made of at least one of glass, polymethyl methacrylate, polystyrene and polycarbonate.

2. The method according to claim 1, wherein the first mold is made of glass, and the second mold is made of polymethyl methacrylate.

3. The method of claim 1, wherein the first and second crosslinking agents each comprise at least one of N, N' -methylenebisacrylamide, ethylene glycol dimethacrylate;

And/or, the first photoinitiator and the second photoinitiator comprise at least one of phenyl (2, 4, 6-trimethylbenzoyl) lithium phosphate and a photoinitiator 2959;

And/or the mass ratio of the first monomer to the first cross-linking agent to the first photoinitiator is (15-22): 0.1-1): 0.01-0.03;

and/or the mass ratio of the second monomer to the second crosslinking agent to the second photoinitiator is (10-14): 0.05-0.2): 0.01-0.03.

4. The method according to claim 1, wherein the first and second ultraviolet irradiation are each performed for a period of 1 to 5 hours at a wavelength of 350 to 370 nm;

And/or, the preparation method of the ultra-smooth double-network hydrogel based on the inhibition effect further comprises the step of performing second swelling on the intermediate product obtained after the second ultraviolet irradiation in pure water;

and/or the first swelling time is 40-56h.

5. The method of claim 4, wherein the second swelling time is 40-56 hours;

and/or, in the process of carrying out second swelling on the intermediate product obtained after the second ultraviolet irradiation in pure water, the pure water is replaced every 10-12 hours.

6. An inhibitory effect-based ultra-smooth dual-network hydrogel prepared by the preparation method according to any one of claims 1 to 5.

7. The inhibitory effect-based super-slip dual-network hydrogel of claim 6, wherein said inhibitory effect-based super-slip dual-network hydrogel comprises said first layer of network hydrogel and a second layer of network hydrogel, said second layer of network hydrogel coating at least a portion of an outer surface layer of said first layer of network hydrogel.

8. The inhibitory effect-based super-slippery double-network hydrogel according to claim 6, wherein the coefficient of friction of the inhibitory effect-based super-slippery double-network hydrogel is 0.00383-0.01.

9. Use of the ultra-smooth dual network hydrogel based on inhibition effect according to any one of claims 6 to 8 in the field of soft robotics, in the field of medical device surface lubrication, or as a material in the field of cartilage repair.