阅读说明：本技术 一种导电水凝胶的制备方法 (Preparation method of conductive hydrogel ) 是由 刘瑞来 何欢 梁松 李泽彪 赵瑨云 胡家朋 林皓 穆寄林 于 2020-08-06 设计创作，主要内容包括：本发明提供一种导电水凝胶的制备方法,步骤包括：纤维素多孔纳米纤维的制备；N-(4-氨苯基)丙烯酰胺的合成；纤维素多孔纳米纤维接枝聚(丙烯酰胺-co-N-(4-氨苯基)丙烯酰胺)水凝胶的制备；纤维素多孔纳米纤维接枝聚(丙烯酰胺-co-N-(4-氨苯基)丙烯酰胺)接枝聚(苯胺-co-对苯二胺)水凝胶的制备。本发明得到的新型导电水凝胶具有成本低廉、工艺简单、导电性良好、循环稳定性好、热稳定性优异等优点,具有良好的工业应用前景。(The invention provides a preparation method of conductive hydrogel, which comprises the following steps: preparing cellulose porous nano-fibers; synthesizing N- (4-aminophenyl) acrylamide; preparing a cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel; preparation of cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel. The novel conductive hydrogel obtained by the invention has the advantages of low cost, simple process, good conductivity, good cycle stability, excellent thermal stability and the like, and has good industrial application prospect.)

1. A preparation method of the conductive hydrogel is characterized by comprising the following steps:

preparing cellulose porous nano-fibers;

synthesizing N- (4-aminophenyl) acrylamide;

preparing a cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel by using the cellulose porous nanofiber and N- (4-aminophenyl) acrylamide;

preparing a cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel by using the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel, namely the conductive hydrogel.

2. The method for preparing the electrically conductive hydrogel according to claim 1, wherein the cellulose porous nanofiber is prepared by:

adding cellulose triacetate and polyurethane into a mixed solvent of N, N' -dimethylformamide and acetone, dissolving to obtain cellulose triacetate and polyurethane, and adding nano SiO₂Adding into acetone to obtain SiO₂Suspending the dispersion, and mixing the SiO₂Adding the suspension dispersion liquid into a cellulose triacetate/polyurethane solution, and uniformly dispersing to form a mixed solution;

quenching the mixed solution at-40 to-20 ℃ for 120-180 min, extracting with distilled water to remove N, N' -dimethylformamide and acetone, and freeze-drying to obtain cellulose triacetate/polyurethane/SiO₂Compounding nano fiber;

mixing the cellulose triacetate/polyurethane/SiO₂Soaking the composite nano-fiber in NaOH/ethanol solution for hydrolysis, washing and drying to obtain cellulose/polyurethane/SiO₂Compounding nano fiber;

mixing the cellulose/polyurethane/SiO₂Soaking the composite nano-fiber in acetone, oscillating at normal temperature for 24h, washing with ethanol, and drying to obtain cellulose/SiO₂Composite porous nanofibers;

mixing the cellulose/SiO₂Soaking the composite porous nano fiber in a mixed solution of hydrofluoric acid and ammonium fluoride to remove SiO₂And then washing and drying to obtain the cellulose porous nanofiber.

3. The method for preparing the conductive hydrogel according to claim 2, wherein the mixed solution contains 3 to 5 mass% of cellulose triacetate, 1 to 2 mass% of polyurethane, and nano SiO₂The mass fraction of the N, N '-dimethylformamide is 0.2-0.5%, and the mass ratio of the N, N' -dimethylformamide to the acetone is (3-5): (1-2).

4. The method of claim 2, wherein the polyurethane is linear polyurethane or nano-SiO₂Has an average particle diameter of not more than 5 nm.

5. The method for preparing the electrically conductive hydrogel according to claim 1, wherein the method for synthesizing the N- (4-aminophenyl) acrylamide comprises the following steps:

under the protection of nitrogen, adding p-phenylenediamine and triethylamine into dichloromethane, dissolving, dropwise adding acryloyl chloride, reacting at 0-2 ℃, filtering after the reaction is finished, collecting filtrate, and carrying out reduced pressure distillation to remove the solvent to obtain the N- (4-aminophenyl) acrylamide.

6. The method for preparing the conductive hydrogel according to claim 5, wherein the mass ratio of p-phenylenediamine, triethylamine and acryloyl chloride is (1-2): (0.3-0.5): (0.3-0.6).

7. The method for preparing the electrically conductive hydrogel according to claim 1, wherein the method for preparing the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel comprises the following steps:

dissolving acrylamide, N- (4-aminophenyl) acrylamide and N, N' -methylene bisacrylamide in a nitric acid solution to obtain a reaction solution A;

dissolving ammonium ceric nitrate in a nitric acid solution, adding cellulose porous nano-fibers, and uniformly dispersing to obtain a reaction solution B;

and dropwise adding the reaction solution A into the reaction solution B, and reacting at 30-50 ℃ to obtain the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel.

8. The method for preparing the conductive hydrogel according to claim 7, wherein the mass ratio of the acrylamide to the N- (4-aminophenyl) acrylamide to the N, N' -methylenebisacrylamide is (10-15): (1-2): (0.1 to 0.3); the mass ratio of the ammonium ceric nitrate to the cellulose porous nano-fiber is (2-5): (0.5-2).

9. The method for preparing the electrically conductive hydrogel according to claim 1, wherein the method for preparing the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel comprises the following steps:

adding cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel into a dilute hydrochloric acid solution, adding aniline and p-phenylenediamine, dropwise adding an ammonium persulfate aqueous solution at 0-4 ℃, and reacting at 15-25 ℃ to obtain the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel.

10. The method for preparing the conductive hydrogel according to claim 9, wherein the mass ratio of aniline to p-phenylenediamine is (2-3): (0.5-1), wherein the mass fraction of the ammonium persulfate aqueous solution is 15-20%.

Technical Field

The invention relates to a preparation method of novel conductive hydrogel, belonging to the fields of functional polymer materials and electrochemistry.

Background

With the development of science and technology, electronic equipment is more and more widely applied. The flexible electronic equipment has the advantages of softness, light weight, deformability and the like, and is widely applied to various fields. The flexible super capacitor has the advantages of being simple in structure and convenient to use. The super capacitor has the advantages of high power density and energy density, high charging speed, low production cost, excellent cycling stability, environmental friendliness and the like, and thus becomes a main device of the flexible electronic equipment.

The key link of the flexible supercapacitor preparation lies in the preparation of the flexible electrode material. The electrode material of the super capacitor mainly comprises the following three types: carbon materials, transition metal compounds, conductive polymers. These three types of materials are rigid materials and do not have flexibility. Therefore, in order to prepare flexible electrode materials, researchers often transfer or load the three types of materials to a toolA substrate of flexible material to impart flexibility thereto. Common substrate materials include elastomeric rubber, polydimethylsiloxane, cotton, and the like. For example: yang et al prepared a fibrous-flexible supercapacitor by orderly wrapping carbon nanotubes on elastic rubber fibers, which still had a specific capacitance of 18F/g after 100 cycles of 75% bending (Yang Z, et al, ahigh string, fiber-shaped supercapacitor [ J)]Angle. chem. edition,2013,52, 13453). Hu et al use a fabric worn in general to support single-walled carbon nanotubes on its surface by impregnation to obtain a conductive fabric. The conductivity of the fabric is 125S/cm, and the resistance is less than 1 omega/sq. And the conductive fabric shows excellent flexibility and bendability, and the specific capacitance is as high as 0.48F/cm²(Hu L,et al.,Stretchable,porous,and conductiveenergy textiles,Nano Lett.2010,10,704)。

Although the above method can prepare the flexible electrode material to a certain extent, it has some defects, such as tedious preparation steps and low industrialization level; flexible substrate materials, while providing flexibility, contribute significant mass and weight to the device, causing deterioration in electrochemical performance. The flexible substrate and the active material cannot be completely combined together, contact resistance exists between the flexible substrate and the active material, the flexible substrate and the active material are easy to fall off under violent movement, and the electrochemical stability is poor. For the above reasons, developing a flexible electrode material with good electrochemical stability, strong flexibility and simple process is the focus of the scientist.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method of a conductive hydrogel.

A preparation method of conductive hydrogel comprises the following steps:

preparing cellulose porous nano-fibers;

synthesizing N- (4-aminophenyl) acrylamide;

preparing a cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel by using the cellulose porous nanofiber and N- (4-aminophenyl) acrylamide;

preparing a cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel by using the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel, namely the conductive hydrogel.

Preferably, the preparation method of the cellulose porous nanofiber comprises the following steps:

adding cellulose triacetate and polyurethane into a mixed solvent of N, N' -dimethylformamide and acetone, dissolving to obtain cellulose triacetate and polyurethane, and adding nano SiO₂Adding into acetone to obtain SiO₂Suspending the dispersion, and mixing the SiO₂Adding the suspension dispersion liquid into a cellulose triacetate/polyurethane solution, and uniformly dispersing to form a mixed solution;

quenching the mixed solution at-40 to-20 ℃ for 120-180 min, extracting with distilled water to remove N, N' -dimethylformamide and acetone, and freeze-drying to obtain cellulose triacetate/polyurethane/SiO₂Compounding nano fiber;

mixing the cellulose triacetate/polyurethane/SiO₂Soaking the composite nano-fiber in NaOH/ethanol solution for hydrolysis, washing and drying to obtain cellulose/polyurethane/SiO₂Compounding nano fiber;

mixing the cellulose/polyurethane/SiO₂Soaking the composite nano-fiber in acetone, oscillating for 24h at normal temperature, washing with ethanol, and drying to obtain cellulose/SiO₂Composite porous nanofibers;

mixing the cellulose/SiO₂Soaking the composite porous nano fiber in a mixed solution of hydrofluoric acid and ammonium fluoride to remove SiO₂And then washing and drying to obtain the cellulose porous nanofiber.

Preferably, in the mixed solution, the mass fraction of the cellulose triacetate is 3-5%, the mass fraction of the polyurethane is 1-2%, and the nano SiO is₂The mass fraction of the N, N '-dimethylformamide is 0.2-0.5%, and the mass ratio of the N, N' -dimethylformamide to the acetone is (3-5): (1-2).

Preferably, the polyurethane is linear polyurethane or nano SiO₂Has an average particle diameter of not more than 5 nm.

Preferably, the synthesis method of the N- (4-aminophenyl) acrylamide comprises the following steps:

under the protection of nitrogen, adding p-phenylenediamine and triethylamine into dichloromethane, dissolving, dropwise adding acryloyl chloride, reacting at 0-2 ℃, filtering after the reaction is finished, collecting filtrate, and carrying out reduced pressure distillation to remove the solvent to obtain the N- (4-aminophenyl) acrylamide.

Preferably, the mass ratio of the p-phenylenediamine to the triethylamine to the acryloyl chloride is (1-2): (0.3-0.5): (0.3-0.6).

Preferably, the preparation method of the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel comprises the following steps:

dissolving acrylamide, N- (4-aminophenyl) acrylamide and N, N' -methylene bisacrylamide in a nitric acid solution to obtain a reaction solution A;

dissolving ammonium ceric nitrate in a nitric acid solution, adding cellulose porous nano-fibers, and uniformly dispersing to obtain a reaction solution B;

and dropwise adding the reaction solution A into the reaction solution B, and reacting at 30-50 ℃ to obtain the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel.

Preferably, the mass ratio of the acrylamide to the N- (4-aminophenyl) acrylamide to the N, N' -methylenebisacrylamide is (10-15): (1-2): (0.1 to 0.3); the mass ratio of the ammonium ceric nitrate to the cellulose porous nano-fiber is (2-5): (0.5-2).

Preferably, the preparation method of the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel comprises the following steps:

adding cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel into a dilute hydrochloric acid solution, adding aniline and p-phenylenediamine, dropwise adding an ammonium persulfate aqueous solution at 0-4 ℃, and reacting at 15-25 ℃ to obtain the cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel.

Preferably, the mass ratio of the aniline to the p-phenylenediamine is (2-3): (0.5-1), wherein the mass fraction of the ammonium persulfate aqueous solution is 15-20%.

The basic principle of the invention is as follows:

1. preparation of cellulose triacetate/polyurethane/SiO by thermally induced phase separation₂Composite nano fiber, through a series of soaking and washing to remove polyurethane and SiO₂Obtaining cellulose porous nano-fibers;

2. taking cellulose porous nano-fiber as a template and N, N' -methylene bisacrylamide as a cross-linking agent, and grafting and copolymerizing acrylamide and N- (4-aminophenyl) acrylamide on the porous fiber to obtain cellulose porous nano-fiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) hydrogel;

3. by using N- (4-aminophenyl) acrylamide as an active point, aniline and p-phenylenediamine are grafted and copolymerized on the hydrogel to obtain a cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel;

compared with the prior art, the invention has the following beneficial effects:

1. by utilizing the high porosity and large specific surface area of the cellulose porous nanofiber, aniline and p-phenylenediamine are grafted on the surface of the cellulose porous nanofiber, so that the specific surface area of the conductive hydrogel is greatly improved, and the specific capacitance of the material is improved;

2. aniline and p-phenylenediamine are grafted onto the hydrogel in situ by utilizing the flexibility and bendability of the hydrogel to prepare the conductive hydrogel flexible electrode material, so that the bendability of the electrode material is greatly improved;

3. the polyaniline-co-p-phenylenediamine and the matrix gel are subjected to graft polymerization. Compared with an in-situ polymerization mode, the in-situ graft polymerization mode is more favorable for forming a continuous conductive channel in a hydrogel network, so that the conductivity of the material is greatly improved;

4. the conductive hydrogel prepared by the invention has the characteristics of stable preparation process, easiness in operation, low equipment dependence, no pollution and the like, is suitable for industrial large-scale production, and is expected to become an ideal flexible supercapacitor electrode material.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of the preparation of a cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) hydrogel according to the present invention;

FIG. 2 is a scanning electron microscope image of a hydrogel of cellulose porous nanofiber grafted poly (acrylamide-co-N- (4-aminophenyl) acrylamide) grafted poly (aniline-co-p-phenylenediamine) prepared in example 1 of the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.