Nanowire-reinforced hydrogel raw material composition, nanowire-reinforced hydrogel and preparation method and application

Abstract

The application discloses a nanowire reinforced hydrogel raw material composition, a nanowire reinforced hydrogel and a preparation method and application. The raw material composition comprises: potassium-based and / or sodium-based oxygen-containing acid salt nanowires exchanged with reducing low-valence transition metal ions, a water-soluble polymer compound, acrylamide and an initiator; the mass ratio of the potassium-based and / or sodium-based oxygen-containing acid salt nanowires exchanged with reducing low-valence transition metal ions to the water-soluble polymer compound is 1:(10-300), the mass ratio of the water-soluble polymer compound to the acrylamide is 1:(0.5-20), and the mass ratio of the acrylamide to the initiator is 1:(0.001-0.1). The nanowire reinforced hydrogel prepared by the application has high tensile property, high toughness and good elasticity.

Description

Technical Field

[0001] The present invention specifically relates to a nanowire-enhanced hydrogel raw material composition, a nanowire-enhanced hydrogel, a preparation method, and an application. Background Art

[0002] Inspired by the ion conduction properties and sensory functions of the skin, artificial ion skin (hydrogels, ion gels, ion elastomers, etc.) based on ion conduction can realize a variety of sensing functions such as temperature, pressure and strain. Among them, hydrogels are mainly composed of a hydrophilic polymer three-dimensional network structure, which can swell rapidly in water. They have 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 gives it high ion conductivity and excellent biocompatibility. However, the skin not only has ion conduction and sensory functions, but also needs to maintain its original shape and function during repeated deformation to restore its original mechanical properties and sensory capabilities. Therefore, the artificial ion skin of the hydrogel system needs to further develop elasticity to improve its functions.

[0003] The elasticity of a hydrogel reflects the ability of a polymer network to recover its original shape. Based on the reversibility of the polymer network's recovery, it can be divided into elastic deformation and plastic deformation. Elastic deformation refers to the portion of the polymer network that can recover its original shape during deformation, while plastic deformation refers to the portion that cannot recover its original shape. Hydrogels often chemically crosslink polymer chains to stabilize the polymer network, so that only relative positions change during deformation, thereby improving elastic deformation. However, chemically crosslinked hydrogels have poor toughness, are prone to breakage, and are difficult to resist crack expansion, affecting the long-term use of electronic skin. Therefore, it is particularly important to develop a hydrogel that is both elastic and highly tough. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of existing hydrogel systems in artificial ionic skin, which suffer from poor elasticity and toughness. The invention provides a nanowire-enhanced hydrogel raw material composition, a nanowire-enhanced hydrogel, and a preparation method and application. The nanowire-enhanced hydrogel prepared by the present invention exhibits high stretchability, high toughness, and good elasticity.

[0005] The present invention uses acrylamide, a water-soluble high molecular polymer, an initiator, and potassium- or sodium-based oxygen-containing salt nanowires exchanged with reducing low-valent transition metal ions to prepare a sodium titanate nanowire-reinforced hydrogel with a double network structure, wherein acrylamide is polymerized outward along the ion-exchange nanowires in the presence of reducing low-valent transition metal ions to form polyacrylamide as the first heavy hydrogen bond network (during the reaction, the low-valent transition metal ions are oxidized to a high-valent state), and the water-soluble high molecular polymer is the second heavy network. The water-soluble high molecular polymer forms coordination bonds and hydrogen bond networks with the ion-exchange nanowires and polyacrylamide, respectively, and is anchored around the nanowires to form a polymer network with the nanowires as crosslinking points. The double network composed of ion-exchange nanowires as anchor points mimics the intermuscular spine structure in fish bodies, so that the peripheral polymer chains always only change their relative positions during repeated deformation, maintaining elastic deformation.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a nanowire-enhanced hydrogel raw material composition, which comprises the following components: potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions, a water-soluble polymer compound, acrylamide and an initiator;

[0008] The mass ratio of the potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions to the water-soluble polymer compound is 1:(10-300), the mass ratio of the water-soluble polymer compound to the acrylamide is 1:(0.5-20), and the mass ratio of the acrylamide to the initiator is 1:(0.001-0.1).

[0009] In the present invention, the reducing low-valent transition metal ion is preferably Sn 2+ 、Cu + 、Fe 2+ 、Mn 2+ 、Ti 3+ 、Ru 3+ 、Nb 3+ 、Ta 3+ and V 3+ One or more of .

[0010] In the present invention, in the potassium- and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions, the molar ratio of "potassium- and / or sodium-based oxyacid salt nanowires" to the reducing low-valent transition metal ions can be 1: (5-100), preferably 1: (10-80).

[0011] In the present invention, according to the conventional art, the potassium-based and / or sodium-based oxoacid salt nanowires are generally layered materials.

[0012] In the present invention, the potassium-based and / or sodium-based oxyacid salt is preferably a titanate or a manganate, such as Na2Ti3O7, Na2Ti6O 13 Or Na 0.44 M n O2.

[0013] In a specific embodiment, the potassium-based and / or sodium-based oxoacid salt nanowires are Na2Ti3O7 nanowires.

[0014] In the present invention, the preparation method of the potassium and / or sodium oxyacid salt nanowires exchanged with reducing low-valent transition metal ions preferably includes the following steps: mixing the "potassium and / or sodium oxyacid salt nanowires" and a reducing low-valent transition metal salt solution to achieve ion exchange; wherein the molar ratio of the "potassium and / or sodium oxyacid salt nanowires" to the reducing low-valent transition metal salt is 1:(5-100).

[0015] The diameter of the potassium-based and / or sodium-based oxoacid nanowires may be 0.01-1 μm, and the length of the potassium-based and / or sodium-based oxoacid nanowires may be 0.1-1000 μm.

[0016] Among them, the preparation method of the "potassium-based and / or sodium-based oxyacid salt nanowires" can be conventional in the art, and preferably includes the following steps: a mixed solution containing "titanium dioxide or manganese oxide" and a strong base is subjected to a hydrothermal reaction at 170-210°C for 18-96 hours, followed by washing and drying.

[0017] The strong base may be sodium hydroxide and / or potassium hydroxide. In the mixed solution, the concentration of the strong base may be 5-12 M, for example, 10 M. The mass ratio of the titanium dioxide or manganese oxide to the strong base may be 1:(100-140), for example, 1:120. The hydrothermal reaction temperature may be 180-200°C, for example, 190°C. The hydrothermal reaction time may be 18-30 hours, for example, 24 hours.

[0018] Among them, the reducing low-valent transition metal salt is preferably one or more of hydrochlorides, sulfates and nitrates of reducing low-valent transition metals, for example, one or more of stannous chloride, stannous sulfate, cuprous sulfate, cuprous chloride, ferrous sulfate and ferrous chloride.

[0019] The concentration of the reducing low-valent transition metal salt solution may be (0.05-1) g / mL, preferably (0.05-0.5) g / mL, such as 0.08 g / mL, 0.1 g / mL, 0.12 g / mL or 0.2 g / mL.

[0020] The molar ratio of the "potassium-based and / or sodium-based oxoacid salt nanowires" to the reducing low-valent transition metal salt is preferably 1:(10-80), such as 1:15.9, 1:21.3, 1:27.1 or 1:71.7.

[0021] The mixing method can be conventional in the art, such as stirring or ultrasound. The mixing time can be 10 min-6 h, preferably 0.5 h-2 h, such as 0.5 h, 1 h, 1.5 h or 2 h.

[0022] According to the conventional art, after the mixing is completed, filtration and washing, such as suction filtration, are generally required.

[0023] During the preparation process of the potassium and / or sodium oxyacid salt nanowires exchanged with reducing low-valent transition metal ions, the metal cations in the reducing low-valent transition metal salt are ion-exchanged with the cations in the "potassium and / or sodium oxyacid salt nanowires". The higher the concentration of the reducing low-valent transition metal salt solution and the longer the mixing time, the higher the content of transition metal ions in the potassium and / or sodium oxyacid salt nanowires exchanged with reducing low-valent transition metal ions; the molar ratio of the "potassium or sodium oxyacid salt nanowires" and the reducing low-valent transition metal salt affects the distribution ratio of the reducing low-valent transition metal cations in the nanowires.

[0024] In the present invention, the water-soluble polymer compound can be a carboxyl-containing polymer, preferably one or more of sodium alginate, polyacrylic acid, and carboxymethyl cellulose. The carboxyl groups in the water-soluble polymer compound form coordination bonds with the cations in the potassium and / or sodium oxoacid salt nanowires exchanged with reducing low-valent transition metal ions, thereby facilitating the dispersion of the nanowires and strengthening the hydrogel.

[0025] In the present invention, the initiator can be a water-soluble free radical initiator, preferably one or more of ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid and azobisisopropylimidazoline.

[0026] In the present invention, the mass ratio of the potassium and / or sodium oxoacid salt nanowires exchanged with reducing low-valent transition metal ions and the water-soluble polymer compound is preferably 1:(10-200), for example, 1:40, 1:50, 1:55.6, 1:80, 1:100, 1:143, 1:200, and more preferably 1:(20-50).

[0027] In the present invention, the mass ratio of the water-soluble polymer compound to the acrylamide is preferably 1:(1-10), such as 1:1, 1:2.5, 1:4 or 1:8.

[0028] In the present invention, the mass ratio of the acrylamide to the initiator is preferably 1:(0.01-0.05), such as 1:0.02, 1:0.025 or 1:0.0375.

[0029] In the present invention, the nanowire-enhanced hydrogel raw material composition preferably further comprises a solvent.

[0030] The solvent may be one or more of deionized water, ethanol, ethylene glycol and glycerol.

[0031] The ratio of the sum of the masses of the potassium and / or sodium oxoacid salt nanowires exchanged with reducing low-valent transition metal ions, the water-soluble polymer compound, the acrylamide, and the initiator to the volume of the solvent may be (0.1-2.0) g / mL, preferably (0.2-1.0) g / mL, for example, 0.44 g / mL, 0.49 g / mL, or 0.68 g / mL.

[0032] In the present invention, the nanowire-enhanced hydrogel raw material composition preferably comprises the following components: potassium- and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions, a "mixed solution containing a water-soluble polymer compound and acrylamide" and a "solution containing an initiator";

[0033] The mass ratio of the potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions to the water-soluble polymer compound is 1:(10-300), the mass ratio of the water-soluble polymer compound to the acrylamide is 1:(0.5-20), and the mass ratio of the acrylamide to the initiator is 1:(0.001-0.1).

[0034] The solvents in the "mixed solution containing a water-soluble polymer and acrylamide" and the "solution containing an initiator" are as described above.

[0035] In the "mixed solution containing a water-soluble polymer and acrylamide", the concentration of acrylamide may be (0.1-1) g / mL, such as 0.2 g / mL, 0.4 g / mL, 0.5 g / mL or 0.8 g / mL.

[0036] Wherein, in the “solution containing an initiator”, the concentration of the initiator may be (0.1-1) g / mL, such as 0.2 g / mL, 0.25 g / mL or 0.3 g / mL.

[0037] The present invention also provides a nanowire-enhanced hydrogel, which is prepared by mixing the nanowire-enhanced hydrogel raw material composition as described above.

[0038] In the present invention, the nanowire-enhanced hydrogel can be prepared into hydrogel products with different morphologies and sizes according to actual application requirements, for example, into a hydrogel film.

[0039] In the present invention, the breaking length of the nanowire-reinforced hydrogel can be 500%-2500%.

[0040] In the present invention, the breaking strength of the nanowire-reinforced hydrogel may be 50-300 kPa.

[0041] The present invention also provides a method for preparing the nanowire-enhanced hydrogel, which comprises the following steps:

[0042] Method 1: (1) dissolving the water-soluble polymer compound and the acrylamide in a solvent to prepare a solution A; mixing the potassium-based and / or sodium-based oxoacid salt nanowires exchanged with reducing low-valent transition metal ions with the solution A to prepare a solution B;

[0043] (2) dissolving the initiator in a solvent to prepare a solution C, then mixing the solution C with the solution B and allowing the mixture to stand for a period of time;

[0044] Alternatively, method 2: (1) dissolving the water-soluble polymer compound and the acrylamide in a solvent to obtain a solution A; dissolving the initiator in a solvent to obtain a solution C; mixing the solution A and the solution C to obtain a solution D;

[0045] (2) The potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions are sprayed onto a glass sheet, and then the solution D is added to the surface of the nanowires and allowed to stand for a period of time.

[0046] In method 1 and / or method 2, the solvent is as described above.

[0047] In method 1 and / or method 2, the mixing method can be conventional in the art, such as stirring or ultrasound. In method 1, preferably, the solution C is added to the solution B and then mixed.

[0048] In method 1 and / or method 2, there is generally no order in which solution A and solution C are prepared, for example, solution A is prepared first and then solution C, or solution C is prepared first and then solution A, or they are prepared simultaneously.

[0049] In method 2, the potassium and / or sodium oxoacid salt nanowires exchanged with reducing low-valent transition metal ions are generally prepared into a dispersion for spray coating. The solvent in the dispersion can be a conventional volatile solvent in the art, such as ethanol. The concentration of the dispersion is generally not particularly limited, but is preferably (1-10) mg / mL, for example, 3 mg / mL, 4.7 mg / mL, or 6 mg / mL.

[0050] In method 1 and / or method 2, the standing still is generally performed in a mold. The standing still time can be 10 minutes to 10 hours, preferably 1 to 5 hours, such as 1 hour, 2 hours or 5 hours.

[0051] In method 1 and / or method 2, the standing temperature may be -10°C to 80°C, such as 25°C, 40°C or 60°C, preferably 15-40°C.

[0052] After the solution C and the solution B are mixed, the reducing low-valent transition metal ions on the surface of the nanowires accelerate the decomposition of the initiator into highly active free radicals, which react to generate high-valent transition metal ions, causing the acrylamide monomer to undergo polymerization at room temperature to obtain a hydrogel that grows epitaxially along the nanowires.

[0053] The amount of the initiator used will affect the polymerization reaction rate and the mechanical properties of the hydrogel. Too much initiator will cause a violent reaction and explosion, while too little will require a longer standing time. The standing time will affect the completeness of the polymerization reaction, while too short a standing time will lead to incomplete polymerization.

[0054] The present invention also provides an application of the nanowire-enhanced hydrogel as described above in the fields of electronic skin, flexible sensors, artificial muscles or gel electrolytes.

[0055] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0056] The reagents and raw materials used in the present invention are commercially available.

[0057] The positive progress effect of the present invention is:

[0058] The nanowire-reinforced hydrogel prepared by the present invention has the following advantages:

[0059] (1) Excellent tensile properties: Under the action of the entangled network of polyacrylamide and water-soluble polymer, the hydrogel can obtain high tensile properties through the gradual untangling of the network;

[0060] (2) High toughness: Under the coordination bonds and hydrogen bonds of polyacrylamide and water-soluble polymers, the hydrogel obtains high toughness through the dissipation of reversible physical bonds and hinders the expansion of wound cracks;

[0061] (3) High elasticity: Under the anchoring effect of ion exchange nanowires, the polymer only changes its relative position and can return to its original structure after rebound. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 These are photos of the polyacrylamide-polyacrylic acid-tin ion exchange hydrogel composition sample prepared in Example 1 (a) before polymerization and (b) after polymerization at room temperature;

[0063] Figure 2 Part (a) is a cryo-electron micrograph of the polyacrylamide-polyacrylic acid-tin ion exchange hydrogel composition sample prepared in Example 1; Figure 2 Part (b) is a cryo-electron micrograph of the polyacrylamide-polyacrylic acid-sodium titanate hydrogel composition sample prepared in Comparative Example 6;

[0064] Figure 3 Part (a) is a white gel of the polyacrylamide-polyacrylic acid-tin ion exchange hydrogel composition sample prepared in Example 7, which is in situ anchored and grown on the ion-exchanged sodium titanate nanowires on a glass slide; Figure 3 Part (b) is the disordered transparent gel grown on the sodium titanate nanowires without ion exchange in Comparative Example 5;

[0065] Figure 4 Part (a) is a pressure-stretch curve of the polyacrylamide-polyacrylic acid-tin ion exchange hydrogel composition sample prepared in Example 1 under cyclic stretching of 1 times the initial length; Figure 2 Part (b) is a pressure-stretch curve of the polyacrylamide-polyacrylic acid hydrogel composition sample prepared in Comparative Example 1 under cyclic stretching of 1 times the initial length;

[0066] Figure 5 Part (a) is a pressure-stretch curve of the polyacrylamide-carboxymethyl cellulose-tin ion exchange hydrogel composition sample prepared in Example 2 under cyclic stretching of 1 times the initial length; Figure 3 Part (b) is a pressure-stretch curve of the polyacrylamide-carboxymethyl cellulose hydrogel composition sample prepared in Comparative Example 2 under cyclic stretching of 1 times the initial length;

[0067] Figure 6 The pressure-stretch curves of the polyacrylamide-polyacrylic acid-copper ion exchange hydrogel composition samples prepared in Example 3 and Examples 5-6 and the polyacrylamide-polyacrylic acid sample prepared in Comparative Example 3;

[0068] Figure 7The pressure-stretch curves of the polyacrylamide-polyacrylic acid-copper ion exchange hydrogel composition samples prepared in Example 3 and Examples 5-6 and the polyacrylamide-polyacrylic acid sample prepared in Comparative Example 3 under cyclic stretching of 1 times the initial length are shown;

[0069] Figure 8 Part (a) is a pressure-stretch curve of the polyacrylamide-sodium alginate-iron ion exchange hydrogel composition sample prepared in Example 4 and the polyacrylamide-sodium alginate composition sample prepared in Comparative Example 4 under cyclic stretching of 1 times the initial length;

[0070] Figure 9 This is a current signal diagram of the polyacrylamide-sodium alginate-iron ion exchange hydrogel composition sample prepared in Example 4 when used as a flexible sensor under long-term cyclic operation. DETAILED DESCRIPTION

[0071] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0072] The raw material information used in the following examples and comparative examples is shown in Table 1:

[0073] Table 1

[0074]

[0075]

[0076] The preparation method of sodium titanate nanowires used in the following examples is as follows: 12 g of sodium hydroxide is dissolved in 30 mL of deionized water to obtain a sodium hydroxide solution; 0.1 g of titanium dioxide powder is dispersed in a reactor filled with the sodium hydroxide solution, and a hydrothermal reaction is carried out at 190° C. for 24 h. The resulting product is washed with deionized water until neutral and dried to obtain sodium titanate nanowires (diameter 0.5-2 μm, length 5-10 μm).

[0077] The size of the mold used in the following Examples 1-6 and Comparative Examples 1-4 and Comparative Example 6 is 75 mm*50 mm*1 mm (length*width*thickness).

[0078] Example 1

[0079] (1) Preparation of ion-exchange nanowires: 5 g of stannous chloride was dissolved in 50 g of water to form a stannous chloride solution; 0.5 g of sodium titanate nanowires was immersed in the stannous chloride solution, stirred for 1 hour, and then filtered to obtain stannous ion-exchange sodium titanate nanowires;

[0080] (2) Preparation of hydrogel precursor: 2 g of polyacrylic acid and 5 g of acrylamide were dissolved in 10 mL of water, and 14 mg of stannous ion-exchanged sodium titanate nanowires were added to the polyacrylic acid-acrylamide solution and ultrasonically dispersed to obtain a polyacrylic acid-acrylamide-stannous ion-exchanged sodium titanate nanowire dispersion;

[0081] (3) Preparation of sodium titanate nanowire-reinforced hydrogel: 0.1 g of ammonium persulfate was dissolved in 0.5 g of water to prepare an ammonium persulfate solution; the ammonium persulfate solution was added to the polyacrylic acid-acrylamide-stannous ion exchange sodium titanate nanowire dispersion, stirred evenly, poured into a mold, and allowed to stand at 25°C for 1 hour to obtain a polyacrylamide-polyacrylic acid-tin ion exchange hydrogel composition sample.

[0082] Example 2

[0083] (1) Preparation of ion-exchange nanowires: 4 g of stannous chloride was dissolved in 50 g of water to form a stannous chloride solution; 0.3 g of sodium titanate nanowires was immersed in the stannous chloride solution, stirred for 2 hours, and then filtered to obtain stannous ion-exchange sodium titanate nanowires;

[0084] (2) Preparation of hydrogel precursor: 1 g of carboxymethyl cellulose and 4 g of acrylamide were dissolved in 10 mL of water, and 10 mg of stannous ion-exchanged sodium titanate nanowires were added to the carboxymethyl cellulose-acrylamide solution and ultrasonically dispersed to obtain a carboxymethyl cellulose-acrylamide-stannous ion-exchanged sodium titanate nanowire dispersion;

[0085] (3) Preparation of sodium titanate nanowire-reinforced hydrogel: 0.1 g of ammonium persulfate was dissolved in 0.5 g of water to prepare an ammonium persulfate solution; the ammonium persulfate solution was added to a carboxymethyl cellulose-acrylamide-stannous ion exchange sodium titanate nanowire dispersion, stirred evenly, poured into a mold, and allowed to stand at 25°C for 2 hours to obtain a polyacrylamide-carboxymethyl cellulose-tin ion exchange hydrogel composition sample.

[0086] Example 3

[0087] (1) Preparation of ion exchange nanowires: 10 g of cuprous sulfate was dissolved in 50 g of water to form a cuprous sulfate solution; 0.5 g of sodium titanate nanowires was immersed in the cuprous sulfate solution, stirred for 0.5 hours, and then filtered to obtain cuprous ion exchange sodium titanate nanowires;

[0088] (2) Preparation of hydrogel precursor: 1 g of polyacrylic acid and 4 g of acrylamide were dissolved in 10 mL of water, and 10 mg of cuprous ion-exchanged sodium titanate nanowires were added to the polyacrylic acid-acrylamide solution and ultrasonically dispersed to obtain a polyacrylic acid-acrylamide-cuprous ion-exchanged sodium titanate nanowire dispersion;

[0089] (3) Preparation of sodium titanate nanowire-reinforced hydrogel: 0.15 g of azobis(isobutyl)amidine hydrochloride was dissolved in 0.5 g of water to prepare an azobis(isobutyl)amidine hydrochloride solution; the azobis(isobutyl)amidine hydrochloride solution was added to the polyacrylic acid-acrylamide-cuprous ion exchange sodium titanate nanowire dispersion, stirred evenly, poured into a mold, and allowed to stand at 25°C for 5 hours to obtain a polyacrylamide-polyacrylic acid-cuprous ion exchange hydrogel composition sample.

[0090] Example 4

[0091] (1) Preparation of ion exchange nanowires: 6 g of ferrous chloride was dissolved in 50 g of water to form a ferrous chloride solution; 0.2 g of sodium titanate nanowires was immersed in the ferrous chloride solution, stirred for 1.5 hours, and then filtered to obtain ferrous ion exchange sodium titanate nanowires;

[0092] (2) Preparation of hydrogel precursor. 0.5 g of sodium alginate and 4 g of acrylamide were dissolved in 10 mL of water. 9 mg of ferrous ion exchanged sodium titanate nanowires were added to the sodium alginate-acrylamide solution and ultrasonically dispersed to obtain a sodium alginate-acrylamide-ferrous ion exchanged sodium titanate nanowire dispersion.

[0093] (3) Preparation of sodium titanate nanowire-reinforced hydrogel: 0.15 g of potassium persulfate was dissolved in 0.5 g of water to prepare a potassium persulfate solution; the potassium persulfate solution was added to the sodium alginate-acrylamide-ferrous ion exchange sodium titanate nanowire dispersion, stirred evenly, poured into a mold and allowed to stand at 25°C for 2 hours to obtain a polyacrylamide-sodium alginate-ferric ion exchange hydrogel composition sample.

[0094] Example 5

[0095] Compared with Example 3, except that the amount of cuprous ion-exchanged sodium titanate nanowires added in step (2) was adjusted to 5 mg, the other operations and conditions were the same as those in Example 3.

[0096] Example 6

[0097] Compared with Example 3, except that the amount of cuprous ion-exchanged sodium titanate nanowires added in step (2) was adjusted to 25 mg, the other operations and conditions were the same as those in Example 3.

[0098] Example 7

[0099] (1) Preparation of ion-exchange nanowires: 5 g of stannous chloride was dissolved in 50 g of water to form a stannous chloride solution; 0.5 g of sodium titanate nanowires was immersed in the stannous chloride solution, stirred for 1 hour, and then filtered to obtain stannous ion-exchange sodium titanate nanowires;

[0100] (2) Preparation of sodium titanate nanowire-reinforced hydrogel: 14 mg of stannous ion-exchanged sodium titanate nanowires were dispersed in 3 ml of ethanol. The nanowire dispersion was sprayed onto a glass slide using a spray gun and placed in a cylindrical hollow mold (20 mm in diameter and 10 mm in height).

[0101] 2 g of polyacrylic acid and 5 g of acrylamide were dissolved in 10 mL of water to obtain solution A, and 0.1 g of ammonium persulfate was dissolved in 0.5 g of water to obtain solution C. Solution A and solution C were mixed evenly, poured into a cylindrical hollow mold, and allowed to stand at 25°C for 1 hour to grow an orderly white gel.

[0102] Comparative Example 1

[0103] Dissolve 2 g of polyacrylic acid and 5 g of acrylamide in 10 mL of water to obtain solution A;

[0104] 0.1 g of ammonium persulfate was dissolved in 0.5 g of water to prepare solution C; solution C was added to solution A, stirred evenly, poured into a mold, and allowed to stand at 60° C. for 0.5 hours to obtain a polyacrylamide-polyacrylic acid hydrogel composition sample.

[0105] Comparative Example 2

[0106] Dissolve 1 g of carboxymethyl cellulose and 4 g of acrylamide in 10 mL of water to obtain solution A;

[0107] 0.1 g of ammonium persulfate was dissolved in 0.5 g of water to prepare solution C; solution C was added to solution A, stirred evenly, poured into a mold, and allowed to stand under heating conditions at 60° C. for 0.5 hour to obtain a polyacrylamide-carboxymethyl cellulose hydrogel composition sample.

[0108] Comparative Example 3

[0109] Dissolve 1 g of polyacrylic acid and 4 g of acrylamide in 10 mL of water to obtain solution A;

[0110] 0.15 g of azobisisobutylamidine hydrochloride was dissolved in 0.5 g of water to prepare solution C; solution C was added to solution A, stirred evenly, poured into a mold, and allowed to stand under heating conditions at 60° C. for 0.5 hour to obtain a polyacrylamide-polyacrylic acid hydrogel composition sample.

[0111] Comparative Example 4

[0112] Dissolve 0.5 g of sodium alginate and 4 g of acrylamide in 10 mL of water to obtain solution A;

[0113] 0.15 g of potassium persulfate was dissolved in 0.5 g of water to prepare solution C; solution C was added to solution A, stirred evenly, poured into a mold, and allowed to stand under heating conditions at 60° C. for 0.5 hour to obtain a polyacrylamide-sodium alginate hydrogel composition sample.

[0114] Comparative Example 5

[0115] 14 mg of sodium titanate nanowires were dispersed in 3 ml of ethanol, and the nanowire dispersion was sprayed onto a glass slide using a spray gun and placed in a cylindrical hollow mold (20 mm in diameter and 10 mm in height);

[0116] 2 g of polyacrylic acid and 5 g of acrylamide were dissolved in 10 mL of water to obtain solution A, and 0.1 g of ammonium persulfate was dissolved in 0.5 g of water to obtain solution B. Solution A and solution B were mixed evenly, poured into a cylindrical hollow mold, and allowed to stand under heating conditions at 60°C for 0.5 hours to grow a disordered transparent gel.

[0117] Comparative Example 6

[0118] (1) Preparation of hydrogel precursor: 2 g of polyacrylic acid and 5 g of acrylamide were dissolved in 10 mL of water, and 14 mg of sodium titanate nanowires were added to the polyacrylic acid-acrylamide solution and ultrasonically dispersed to obtain a polyacrylic acid-acrylamide-sodium titanate nanowire dispersion;

[0119] (2) Preparation of sodium titanate nanowire-reinforced hydrogel: 0.1 g of ammonium persulfate was dissolved in 0.5 g of water to prepare an ammonium persulfate solution; the ammonium persulfate solution was added to the polyacrylic acid-acrylamide-sodium titanate nanowire dispersion, stirred evenly, poured into a mold, and allowed to stand at 25°C for 1 hour to obtain a polyacrylamide-polyacrylic acid-sodium titanate hydrogel composition sample.

[0120] Effect embodiment

[0121] (1) Figure 1 These are photos of the polyacrylamide-polyacrylic acid-tin ion exchange sodium titanate nanowire hydrogel composition sample prepared in Example 1 before and after polymerization at room temperature; after standing at room temperature of 25°C for 1 hour, the polyacrylic acid-acrylamide-stannous ion exchange sodium titanate nanowire precursor dispersion was polymerized into a hydrogel.

[0122] Figure 2 Cryo-electron microscopy images of the prepared hydrogel composition samples. (a) shows the in situ growth of polymer chains on the tin ion exchange nanowires after the reaction. Stannous ions can accelerate the generation of free radicals and form a coordination effect with acrylamide, allowing acrylamide to grow on the surface of the nanowires. After deionized water rinsing and centrifugation, the acrylamide remains anchored on the nanowires. However, (b) shows that no polymer chains grow on the nanowires without ion exchange at room temperature.

[0123] according to Figure 3 It can be seen that the polyacrylamide-polyacrylic acid-tin ion exchange hydrogel composition sample prepared in Example 7 forms a white gel that is in situ anchored and grown on the ion-exchanged nanowires on a glass slide. After the coordination effect of the stannous ions aggregates the monomers, the high-density monomers grow in an orderly manner along the outward surface of the ion-exchanged nanowires. However, since Comparative Example 5 uses nanowires that have not been ion-exchanged, it cannot be polymerized into a gel at room temperature. Although polymerization occurs after heating at 60°C, a disordered transparent gel is obtained by growing on the unexchanged nanowires.

[0124] (2) The samples of Examples 1-6 and Comparative Examples 1-4 prepared above (cut into strips with a length * width * thickness of 50 mm * 5 mm * 1 mm) were subjected to pressure-tensile tests. The relevant test results are shown in Figure 4-Figure 8 According to the test results, when nanowires are not added, the residual strain of the curve is obvious, and the stress is unstable with the increase of the number of cycles. However, when nanowires are added, the residual strain is greatly reduced or even disappears, and the stress is stable.

[0125] (3) The polyacrylamide-polyacrylic acid-copper ion exchange hydrogel composition samples prepared in Example 3 and Examples 5-6 and the polyacrylamide-polyacrylic acid sample prepared in Comparative Example 3 (cut into strips with a length * width * thickness of 50 mm * 5 mm * 1 mm) were subjected to pressure-tensile testing. The test results are shown in Table 2:

[0126] Table 2

[0127]

[0128]

[0129] According to the test data in Table 2, when Cu + When ion-exchanged sodium titanate nanowires were added, the fracture toughness and stress of the prepared hydrogel samples were significantly improved.

[0130] (4) The polyacrylamide-sodium alginate-iron ion exchange sodium titanate nanowire hydrogel composition sample prepared in Example 4 (previously cut into strips with a length * width * thickness of 50 mm * 5 mm * 1 mm) was connected to metal electrodes on the upper and lower surfaces to obtain a flexible sensor. Figure 9 This is the current signal diagram of the long-term cyclic operation of the flexible sensor. It can be seen from the figure that the resistance change after 2500 cycles under 100% stretching is negligible, and it has cyclic stability and anti-fatigue performance.

[0131] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A nanowire-enhanced hydrogel raw material composition, characterized in that: The invention comprises the following components: potassium-based and / or sodium-based oxoacid salt nanowires exchanged with reducing low-valent transition metal ions, a water-soluble polymer compound, acrylamide and an initiator; the water-soluble polymer compound is a carboxyl-containing polymer; The mass ratio of the potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions to the water-soluble polymer compound is 1:(10-300), the mass ratio of the water-soluble polymer compound to the acrylamide is 1:(0.5-20), and the mass ratio of the acrylamide to the initiator is 1:(0.001-0.1).

2. The nanowire-enhanced hydrogel raw material composition according to claim 1, characterized in that: The reducing low-valent transition metal ion is Sn 2+ 、Cu + 、Fe 2+ 、Mn 2+ 、Ti 3+ 、Ru 3+ 、Nb 3+ 、Ta 3+ and V 3+ One or more of; And / or, in the potassium- and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions, the molar ratio of "potassium- and / or sodium-based oxyacid salt nanowires" to reducing low-valent transition metal ions is 1:(5-100).

3. The nanowire-enhanced hydrogel raw material composition according to claim 2, characterized in that: In the potassium and / or sodium oxyacid salt nanowires exchanged with reducing low-valent transition metal ions, the molar ratio of "potassium and / or sodium oxyacid salt nanowires" to reducing low-valent transition metal ions is 1:(10-80).

4. The nanowire-enhanced hydrogel raw material composition according to claim 1, characterized in that: The raw material composition satisfies one or more of the following conditions: (1) The water-soluble polymer compound is one or more of sodium alginate, polyacrylic acid and carboxymethyl cellulose; (2) The initiator is a water-soluble free radical initiator; (3) The mass ratio of the potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions to the water-soluble polymer compound is 1:(10-200); (4) The mass ratio of the water-soluble polymer compound to the acrylamide is 1:(1-10); (5) The mass ratio of the acrylamide to the initiator is 1:(0.01-0.05).

5. The nanowire-enhanced hydrogel raw material composition according to claim 4, characterized in that: The initiator is one or more of ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid and azobisisopropylimidazoline.

6. The nanowire-enhanced hydrogel raw material composition according to claim 4, characterized in that: The mass ratio of the potassium and / or sodium oxoacid salt nanowires exchanged with reducing low-valent transition metal ions to the water-soluble polymer compound is 1:40, 1:50, 1:55.6, 1:80, 1:100, 1:143, and 1:

200.

7. The nanowire-enhanced hydrogel raw material composition according to claim 4, characterized in that: The mass ratio of the potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions to the water-soluble polymer compound is 1:(20-50).

8. The nanowire-enhanced hydrogel raw material composition according to claim 4, characterized in that: The mass ratio of the water-soluble polymer compound to the acrylamide is 1:1, 1:2.5, 1:4 or 1:

8.

9. The nanowire-enhanced hydrogel raw material composition according to claim 4, characterized in that: The mass ratio of the acrylamide to the initiator is 1:0.02, 1:0.025 or 1:0.0375.

10. The nanowire-enhanced hydrogel raw material composition according to claim 1, characterized in that: The potassium-based and / or sodium-based oxyacid salt is titanate or manganate; And / or, the method for preparing the potassium- and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions comprises the following steps: mixing the "potassium- and / or sodium-based oxyacid salt nanowires" with a reducing low-valent transition metal salt solution to achieve ion exchange; wherein the molar ratio of the "potassium- and / or sodium-based oxyacid salt nanowires" to the reducing low-valent transition metal salt is 1:(5-100).

11. The nanowire-enhanced hydrogel raw material composition according to claim 10, characterized in that: The potassium and / or sodium oxyacid salts are Na2Ti3O7, Na2Ti6O 13 Or Na 0.44 MnO2.

12. The nanowire-enhanced hydrogel raw material composition according to claim 10, characterized in that: The method for preparing the potassium and / or sodium oxoacid salt nanowires exchanged with reducing low-valent transition metal ions satisfies one or more of the following conditions: (1) The diameter of the "potassium-based and / or sodium-based oxyacid salt nanowires" is 0.01-1 μm; (2) The length of the "potassium-based and / or sodium-based oxyacid salt nanowires" is 0.1-1000 μm; (3) The reducing low-valent transition metal salt is one or more of a hydrochloride, sulfate, and nitrate of a reducing low-valent transition metal; (4) The concentration of the reducing low-valent transition metal salt solution is (0.05-1) g / mL; (5) The molar ratio of the "potassium-based and / or sodium-based oxygen-containing salt nanowires" to the reducible low-valent transition metal salt is 1:(10-80); (6) The mixing time is 10 minutes to 6 hours.

13. The nanowire-enhanced hydrogel raw material composition according to claim 12, characterized in that: The reducing low-valent transition metal salt is one or more of stannous chloride, stannous sulfate, cuprous sulfate, cuprous chloride, ferrous sulfate and ferrous chloride.

14. The nanowire-enhanced hydrogel raw material composition according to claim 12, characterized in that: The concentration of the reducing low-valent transition metal salt solution is (0.05-0.5) g / mL.

15. The nanowire-enhanced hydrogel raw material composition according to claim 14, wherein: The concentration of the reducing low-valent transition metal salt solution is 0.08 g / mL, 0.1 g / mL, 0.12 g / mL or 0.2 g / mL.

16. The nanowire-enhanced hydrogel raw material composition according to claim 12, characterized in that: The molar ratio of the "potassium-based and / or sodium-based oxoacid salt nanowires" to the reducing low-valent transition metal salt is 1:15.9, 1:21.3, 1:27.1 or 1:71.

7.

17. The nanowire-enhanced hydrogel raw material composition according to claim 12, characterized in that: The mixing time is 0.5h-2h.

18. The nanowire-enhanced hydrogel raw material composition according to claim 17, characterized in that: The mixing time is 0.5 h, 1 h, 1.5 h or 2 h.

19. The nanowire-enhanced hydrogel raw material composition according to claim 10, characterized in that: The preparation method of the "potassium-based and / or sodium-based oxoacid salt nanowires" includes the following steps: subjecting a mixed solution containing "titanium dioxide or manganese oxide" and a strong base to a hydrothermal reaction at 170-210°C for 18-96 hours, followed by washing and drying.

20. The nanowire-enhanced hydrogel raw material composition according to claim 19, characterized in that: The strong base is sodium hydroxide and / or potassium hydroxide.

21. The nanowire-enhanced hydrogel raw material composition according to claim 19, characterized in that: In the mixed solution, the concentration of the strong base is 5-12M.

22. The nanowire-enhanced hydrogel raw material composition according to claim 19, wherein: The mass ratio of the "titanium dioxide or manganese oxide" to the strong base is 1:(100-140).

23. The nanowire-enhanced hydrogel raw material composition according to claim 1, characterized in that: The nanowire-enhanced hydrogel raw material composition further includes a solvent; And / or, the nanowire-reinforced hydrogel raw material composition comprises the following components: potassium- and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions, a "mixed solution containing a water-soluble polymer compound and acrylamide", and a "solution containing an initiator".

24. The nanowire-enhanced hydrogel raw material composition according to claim 23, characterized in that: The solvent is one or more of deionized water, ethanol, ethylene glycol and glycerol.

25. The nanowire-enhanced hydrogel raw material composition according to claim 23, characterized in that: The ratio of the sum of the masses of the potassium and / or sodium oxoacid salt nanowires exchanged with reducing low-valent transition metal ions, the water-soluble polymer compound, the acrylamide and the initiator to the volume of the solvent is (0.1-2.0) g / mL.

26. The nanowire-enhanced hydrogel raw material composition according to claim 23, wherein: In the "mixed solution containing a water-soluble polymer and acrylamide", the concentration of acrylamide is (0.1-1) g / mL.

27. The nanowire-enhanced hydrogel raw material composition according to claim 23, wherein: In the "solution containing an initiator", the concentration of the initiator is (0.1-1) g / mL.

28. A nanowire-enhanced hydrogel, characterized in that: The nanowire-enhanced hydrogel is prepared by mixing the nanowire-enhanced hydrogel raw material composition according to any one of claims 1 to 27.

29. A method for preparing a nanowire-enhanced hydrogel according to claim 28, characterized in that: It includes the following steps: Method 1: (1) dissolving the water-soluble polymer compound and the acrylamide in a solvent to prepare a solution A; mixing the potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions with the solution A to prepare a solution B; (2) dissolving the initiator in a solvent to prepare a solution C, and then mixing the solution C with the solution B and allowing the mixture to stand for a period of time; Alternatively, method 2: (1) dissolving the water-soluble polymer compound and the acrylamide in a solvent to obtain solution A; dissolving the initiator in a solvent to obtain solution C; mixing the solution A and the solution C to obtain solution D; (2) The potassium-based and / or sodium-based oxyacid salt nanowires exchanged with reducing low-valent transition metal ions are sprayed onto a glass sheet, and then the solution D is added to the surface of the nanowires and allowed to stand for a period of time.

30. Use of the nanowire-enhanced hydrogel according to claim 28 in the fields of electronic skin, flexible sensors, artificial muscles or gel electrolytes.

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