A hydrogel composition with dynamic bond self-healing function and its preparation method and application

Abstract

The present invention relates to a hydrogel composition with dynamic bond self-healing function and a preparation method and application thereof. The preparation method of the hydrogel composition with dynamic bond self-healing function comprises the following steps: (1) dissolving acrylamide and a water-soluble high molecular polymer in water to form a solution A; dissolving an initiator and a dynamic cross-linking agent in water to form a solution B; (2) adding solution B to solution A, stirring evenly and pouring into a mold, and under heating conditions, acrylamide monomer and the water-soluble high molecular polymer undergo a thermal polymerization reaction via the initiator and the dynamic cross-linking agent to obtain the hydrogel composition with dynamic bond self-healing function.

Description

Technical Field

[0001] The present invention relates to the field of electronic skin, and in particular to a hydrogel composition with high stretchability, self-healing and strong adhesion properties. Background Art

[0002] Inspired by the ion conduction properties and sensory functions of the skin, artificial ion skin (hydrogel, ion gel, ion elastomer, etc.) based on ion conduction can realize multiple sensing functions such as temperature, pressure and strain. Among them, hydrogel is mainly composed of a hydrophilic polymer three-dimensional network structure, which can swell rapidly in water. It has multiple characteristics such as high water content, good flexibility and strong permeability. At the same time, the unique network structure of the hydrogel material system also makes it have high ion conductivity and excellent biocompatibility. However, the skin not only has ion conduction and sensory functions, but also can self-heal after being injured to restore its original mechanical properties and sensory abilities. Therefore, the artificial ion skin of the hydrogel system needs to further develop self-healing properties to improve its functions.

[0003] Self-healing materials are a type of smart material developed in the past decade that can spontaneously repair internal or external damage to restore its original performance. Self-healing material systems usually contain dynamic forces such as non-covalent bonds (hydrogen bonds, van der Waals forces, π-π stacking, ionic bonds, metal-ligand coordination bonds, dipole effects, etc.) or reversible covalent bonds (disulfide bonds, boric acid bonds, imine bonds, etc.), which enable them to reassemble supramolecular networks after being damaged and achieve reversible recovery under mild conditions.

[0004] Existing self-healing systems help hydrogels achieve self-healing functions. Through the combination of non-covalent sacrificial bonds and reversible covalent bonds, they can restore mechanical and electrical properties under certain external stimuli (such as light, pressure, and temperature), completing further bionics of the skin. However, existing self-healing systems can only form weak forces (hydrogen bonds and electrostatic effects) with the surface of human tissue at most, and cannot effectively adhere to the tissue surface. Common solutions, such as grafting functional groups on polymers, often have complex steps, high costs, and are difficult to apply. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a hydrogel composition with dynamic bond self-healing function and a preparation method thereof, wherein the prepared hydrogel composition exhibits excellent self-healing properties and good skin adhesion properties.

[0006] Specifically, in a first aspect, the present invention provides a method for preparing a hydrogel composition with dynamic bond self-healing function, comprising the following steps:

[0007] (1) dissolving acrylamide and a water-soluble high molecular polymer in water to form a solution A; dissolving an initiator and a dynamic crosslinking agent in water to form a solution B;

[0008] (2) adding solution B to solution A, stirring evenly and then pouring into a mold; under heating conditions, acrylamide monomer and water-soluble high molecular polymer undergo thermal polymerization via an initiator and a dynamic crosslinking agent to obtain a hydrogel composition with dynamic bond self-healing function.

[0009] Preferably, the water-soluble high molecular polymer is a high molecular polymer containing hydroxyl groups and / or carboxyl groups, preferably at least one of polyvinyl alcohol, sodium alginate, polyacrylic acid, sodium polyacrylate, and nanocellulose.

[0010] Preferably, the mass ratio of acrylamide to water-soluble high molecular polymer is 1g:(1-0.1g), preferably 1g:(0.5-0.1g), more preferably 1g:(0.3-0.15g), and the concentration of acrylamide in solution A can be 100-1000g / L.

[0011] Preferably, the initiator includes at least one of ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid or azobisisopropylimidazoline, preferably at least one of ammonium persulfate or potassium persulfate, more preferably ammonium persulfate; in the solution B, the concentration of the initiator may be 50 to 500 g / L.

[0012] Preferably, the dynamic crosslinking agent is a boron-containing compound, preferably at least one of boric acid, sodium tetraborate, 3-acrylamidophenylboric acid, 3-hydroxymethylphenylboric acid or 3-carboxymethylphenylboric acid, more preferably at least one of boric acid or 3-acrylamidophenylboric acid, most preferably 3-acrylamidophenylboric acid; in the solution B, the concentration of the dynamic crosslinking agent may be 5 to 50 g / L.

[0013] Preferably, in step (2), after solution B is added to solution A, the ratio of the mass of acrylamide to the mass of the initiator in the mixed solution is controlled to be 1g:(0.001-0.1g), preferably 1g:(0.002-0.05g), more preferably 1g:(0.002-0.005g); the ratio of the mass of acrylamide to the mass of the dynamic cross-linking agent is 1g:(0.001-0.1g), preferably 1g:(0.002-0.05g), more preferably 1g:(0.002-0.005g).

[0014] Preferably, in step (2), the heating temperature is 40 to 90° C., preferably 50 to 80° C., and more preferably 60 to 70° C.; the heating time is 10 to 120 minutes, preferably 10 to 50 minutes, and more preferably 15 to 30 minutes.

[0015] In a second aspect, the present invention provides a hydrogel composition with dynamic bond self-healing function obtained according to the above-mentioned preparation method, wherein the chemical composition of the hydrogel composition with dynamic bond self-healing function includes polyacrylamide, a water-soluble polymer, an initiator and a boron-containing dynamic cross-linking agent.

[0016] In a third aspect, the present invention also provides an application of the above-mentioned hydrogel composition with dynamic bond self-healing function in the fields of electronic skin, flexible sensors, biological tapes, medical bandages, drug carriers or gel electrolytes.

[0017] The self-healing hydrogel for biological tissue adhesion provided by the present invention has a chemical composition of polyacrylamide, a water-soluble high molecular polymer, an initiator and a dynamic crosslinking agent. Compared with the prior art, the present invention conducts a thermal polymerization reaction of acrylamide monomers through a thermal initiator, and under heating conditions and the action of a dynamic crosslinking agent, forms a supramolecular crosslinked hydrogel with reversible dynamic bonds with a high molecular polymer containing carboxyl and / or hydroxyl groups. The dynamic crosslinking agent participates in the reaction, catalyzing the carboxyl groups in the hydrogel to react with the amino groups present in the tissue to form a reversible covalent bond, which is more conducive to tissue adhesion.

[0018] Beneficial Effects

[0019] The hydrogel composition with dynamic bond self-healing function obtained by the preparation method provided by the present invention has the following excellent properties:

[0020] (1) Excellent tensile properties. In the presence of a carboxyl polymer network, acrylamide monomers form a double network with water-soluble polymers during free radical polymerization, giving the hydrogel high elasticity and stretchability;

[0021] (2) Good self-healing properties. In the presence of a boron-containing dynamic crosslinker, the amino group in acrylamide forms a dynamically reversible esterification reaction with the carboxyl group and the hydroxyl group to form a dynamic covalent bond, which together with the physical bond gives the hydrogel good room temperature self-healing properties;

[0022] (3) High interfacial adhesion. The prepared hydrogel composition has abundant hydroxyl and carboxyl groups, which can form hydrogen bonds and reversible covalent bonds with biological epidermal functional groups, thereby forming a good adhesion effect on the biological epidermis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1A schematic diagram of a pressure-stretching curve of a polyacrylamide / polyacrylic acid self-healing hydrogel composition sample prepared in Example 1 is shown;

[0024] Figure 2 A schematic diagram showing the adhesion energy of the polyacrylamide / polyacrylic acid / sodium alginate self-healing hydrogel composition sample prepared in Example 3;

[0025] Figure 3 A confocal microscope image of the self-healing process of the polyacrylamide / polyacrylic acid self-healing hydrogel composition sample prepared in Example 4 is shown. DETAILED DESCRIPTION

[0026] The present invention is further described below by way of embodiments. It should be understood that the following embodiments are only used to illustrate the present invention, but not to limit the present invention. In the following examples, the reagents, materials and instruments used are conventional reagents, conventional materials and conventional instruments, unless otherwise specified, and can be obtained commercially.

[0027] The present invention provides a self-healing hydrogel for biological tissue adhesion, the chemical composition of which is polyacrylamide, a water-soluble high molecular polymer, an initiator and a dynamic crosslinking agent. Compared with the prior art, the present invention conducts a thermal polymerization reaction of acrylamide monomers through a thermal initiator, and under heating conditions and the action of a dynamic crosslinking agent, forms a supramolecular crosslinked hydrogel with reversible dynamic bonds with a high molecular polymer containing carboxyl groups and / or hydroxyl groups. The dynamic crosslinking agent participates in the reaction, catalyzing the reaction of carboxyl groups in the hydrogel with amino groups present in the tissue to form a reversible covalent bond, which is more conducive to tissue adhesion.

[0028] In the present invention, in the presence of a boron-containing dynamic crosslinking agent, the amino group in acrylamide forms a dynamically reversible esterification reaction with the carboxyl group and the hydroxyl group to form a dynamic covalent bond, thereby giving the hydrogel good room temperature self-healing properties.

[0029] The hydrogel composition with dynamic bond self-healing function for biological tissue adhesion provided by the present invention has the characteristics of self-healing, rapid adhesion and simple preparation, and is suitable for large-scale commercial production.

[0030] The following is an exemplary description of the preparation method of the hydrogel composition with dynamic bond self-healing function provided by the present invention.

[0031] Preparation of precursors. Acrylamide and water-soluble polymer are dissolved in water to form solution A. Initiator and dynamic cross-linking agent are dissolved in water to form solution B.

[0032] In an optional embodiment, the water-soluble high molecular polymer is a high molecular polymer containing hydroxyl groups and / or carboxyl groups, preferably one or a combination of polyvinyl alcohol, sodium alginate, polyacrylic acid, sodium polyacrylate, and nanocellulose.

[0033] In an optional embodiment, the mass ratio of acrylamide to water-soluble high molecular polymer may be 1g:(1-0.1g), preferably 1g:(0.5-0.1g), and more preferably 1g:(0.3-0.15g). The concentration of acrylamide in solution A may be 100-1000g / L, and the ratio of acrylamide to water in solution A may be 1g:(0.001-0.01L).

[0034] In an optional embodiment, the initiator includes at least one of ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid or azobisisopropylimidazoline, preferably at least one of ammonium persulfate or potassium persulfate, more preferably ammonium persulfate. In the solution B, the concentration of the initiator can be 50-500 g / L, and the volume ratio of the initiator mass to water can be 1 g: (0.002-0.02 L), preferably 1 g: (0.004-0.01 L), more preferably 1 g: (0.006-0.01 L), and most preferably 1 g: (0.008-0.01 L).

[0035] In an optional embodiment, the dynamic crosslinking agent is a boron-containing compound, preferably at least one of boric acid, sodium tetraborate, 3-acrylamidophenylboric acid, 3-hydroxymethylphenylboric acid or 3-carboxymethylphenylboric acid, more preferably at least one of boric acid and 3-acrylamidophenylboric acid, and most preferably 3-acrylamidophenylboric acid. In the solution B, the concentration of the dynamic crosslinking agent may be 5 to 50 g / L, and the volume ratio of the dynamic crosslinking agent mass to water may be 1 g: (0.02 to 0.2 L), preferably 1 g: (0.04 to 0.1 L), more preferably 1 g: (0.06 to 0.1 L), and most preferably 1 g: (0.08 to 0.1 L).

[0036] Preparation of a hydrogel composition with dynamic bond self-healing function. Solution B is added to solution A to obtain a mixed solution. Preferably, the ratio of the mass of acrylamide in solution A to the mass of the initiator in solution B is controlled to be 1g: (0.001-0.1g), preferably 1g: (0.002-0.05g), and most preferably 1g: (0.002-0.005g). Preferably, the ratio of the mass of acrylamide in solution A to the mass of the dynamic crosslinker in solution B is controlled to be 1g: (0.001-0.1g), preferably 1g: (0.002-0.05g), and most preferably 1g: (0.002-0.005g).

[0037] The amount of initiator used will affect the polymerization rate and the mechanical properties of the hydrogel: when the amount is too high, the polymerization rate will be too fast, causing implosion, thereby reducing the fracture length of the hydrogel; when the amount is too low, the polymerization rate will be too slow, making it difficult for the hydrogel to polymerize, and the fracture strength after polymerization will be reduced. The amount of crosslinker used will affect the crosslinking degree of the hydrogel: when the amount is too high, the crosslinking degree is too high, thereby reducing the fracture length of the hydrogel; when the amount is too low, the crosslinking degree is low, affecting the mechanical properties of the hydrogel.

[0038] The mixed solution obtained by mixing solution A and solution B is stirred and mixed evenly, then poured into a mold, and heated and cured at a certain temperature to obtain a hydrogel composition with dynamic bond self-healing function. The heating and curing temperature can be 40 to 90°C, preferably 50 to 80°C, and more preferably 60 to 70°C. The heating and curing time can be 10 to 120 minutes, preferably 10 to 50 minutes, and more preferably 15 to 30 minutes.

[0039] The following further examples are given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention. The specific process parameters of the following examples are also only an example within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description of this article, and are not limited to the specific values ​​​​exemplified below.

[0040] Example 1

[0041] (1) Preparation of precursor: Weigh 5 g acrylamide and 2 g polyacrylic acid in 10 g water and stir to dissolve; weigh 0.1 g ammonium persulfate and 0.01 g 3-acrylamidophenylboronic acid in 1 g water and stir to disperse by ultrasonic.

[0042] (2) Preparation of a hydrogel composition with dynamic bond self-healing function: Add ammonium persulfate and 3-acrylamidophenylboronic acid solution to an acrylamide-polyacrylic acid solution, and heat at 70° C. for 10 minutes to obtain a polyacrylamide / polyacrylic acid self-healing hydrogel composition sample.

[0043] Figure 1 The schematic diagram of the pressure-stretching curve of the polyacrylamide / polyacrylic acid self-healing hydrogel composition sample prepared in Example 1 is shown. As can be seen from the figure, the fracture strength of the obtained hydrogel is about 275 kPa, and the fracture length is about 1750%.

[0044] Example 2

[0045] (1) Preparation of precursor: Weigh 5 g acrylamide and 0.6 g sodium alginate into 9.4 g water and stir to dissolve; weigh 0.1 g ammonium persulfate and 0.01 g boric acid into 1 g water and stir to disperse by ultrasonic.

[0046] (2) Preparation of a hydrogel composition with dynamic bond self-healing function: Add ammonium persulfate and boric acid solution to an acrylamide-sodium alginate solution, heat at 50° C. for 40 minutes, and obtain a polyacrylamide / sodium alginate self-healing hydrogel composition sample.

[0047] Example 3

[0048] (1) Preparation of precursor: Weigh 5 g of acrylamide, 3 g of polyacrylic acid and sodium alginate in a mass ratio of 2:1, mix and dissolve in 10 g of water, and stir to dissolve; weigh 0.2 g of ammonium persulfate, 0.01 g of boric acid and 0.03 g of sodium tetraborate in 1 g of water, stir and disperse by ultrasonic.

[0049] (2) Preparation of a hydrogel composition with dynamic bond self-healing function: Add ammonium persulfate, boric acid, and sodium tetraborate solution to an acrylamide-polyacrylic acid-sodium alginate solution, and heat at 60°C for 20 minutes to obtain a polyacrylamide / polyacrylic acid / sodium alginate self-healing hydrogel composition sample.

[0050] Figure 2 The schematic diagram of the adhesion energy of the polyacrylamide / polyacrylic acid / sodium alginate self-healing hydrogel composition sample prepared in Example 3 shows that the adhesion of the self-healing hydrogel to wood, titanium foil, pig skin, PET film and glass is 222, 120, 24, 10 and 3 N m -1 .

[0051] Example 4

[0052] (1) Preparation of precursor: Weigh 5 g acrylamide and 2 g polyacrylic acid in 10 g water and stir to dissolve; weigh 0.1 g ammonium persulfate and 0.01 g 3-hydroxymethylphenylboronic acid in 1 g water and stir to disperse by ultrasonic.

[0053] (2) Preparation of a hydrogel composition with dynamic bond self-healing function: Add ammonium persulfate and 3-hydroxymethylphenylboronic acid solution to acrylamide-polyacrylic acid solution, and heat at 60° C. for 30 minutes to obtain a polyacrylamide / polyacrylic acid self-healing hydrogel composition sample.

[0054] Figure 3 The confocal microscope image of the self-healing process of the polyacrylamide / polyacrylic acid self-healing hydrogel composition sample prepared in Example 4 is shown. As can be seen from the figure, the obtained self-healing hydrogel heals spontaneously at room temperature after being cut, and completely recovers to the morphology before cutting after 120 minutes, achieving the recovery of mechanical properties.

Claims

1. A method for preparing a hydrogel composition with dynamic bond self-healing function, characterized in that: The following steps are involved: (1) dissolving acrylamide and a water-soluble polymer in water to form a solution A; dissolving an initiator and a dynamic crosslinking agent in water to form a solution B; the water-soluble polymer is a polymer containing a carboxyl group; the polymer containing a carboxyl group is at least one of sodium alginate, polyacrylic acid, and sodium polyacrylate; the dynamic crosslinking agent is at least one of 3-acrylamidophenylboronic acid, 3-hydroxymethylphenylboronic acid, or 3-carboxymethylphenylboronic acid; (2) adding solution B to solution A, stirring evenly and pouring into a mold, and under heating conditions, acrylamide monomer and water-soluble polymer undergo thermal polymerization reaction via an initiator and a dynamic crosslinker to obtain a hydrogel composition with dynamic bond self-healing function; in the mixed solution obtained after adding solution B to solution A, the mass ratio of acrylamide to water-soluble polymer is 1g:(1-0.1g), the mass ratio of acrylamide to initiator is 1g:(0.001-0.1g), and the mass ratio of acrylamide to dynamic crosslinker is 1g:(0.001-0.1g); The chemical composition of the hydrogel composition with dynamic bond self-healing function includes polyacrylamide, water-soluble high molecular polymer, initiator and boron-containing dynamic cross-linking agent.

2. The preparation method according to claim 1, characterized in that The concentration of acrylamide in solution A is 100-1000 g / L.

3. The preparation method according to claim 1, characterized in that The initiator comprises at least one of ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid or azobisisopropylimidazoline, and the concentration of the initiator in solution B is 50-500 g / L.

4. The preparation method according to claim 1, characterized in that The concentration of the dynamic cross-linking agent in solution B is 5 to 50 g / L.

5. The preparation method according to claim 1, characterized in that: In step (2), the heating temperature is 40 to 90° C. and the heating time is 10 to 120 minutes.

6. Application of a hydrogel composition with dynamic bond self-healing function obtained by the preparation method according to claim 1 in the fields of electronic skin, flexible sensors, biological tapes, medical bandages, drug carriers or gel electrolytes.

Images