阅读说明：本技术 一种利用改性Janus纳米片制备自修复水凝胶的方法 (Method for preparing self-repairing hydrogel by using modified Janus nanosheets ) 是由 柏良久 李梦楠 王文香 陈厚 梁英 牛余忠 杨华伟 杨正龙 于 2019-10-05 设计创作，主要内容包括：本发明公开了利用制备的Janus纳米片构筑自修复纳米复合水凝胶的方法,首先用乳液法制备二氧化硅纳米空心球(SiO<Sub>2</Sub> JSs),然后在其外表面粘附聚多巴胺后粉碎制备Janus@PDA纳米片,利用自由基聚合对其另外一侧进行改性接枝聚甲基丙烯酸异氰基乙酯制备具有双重自修复性能的SiO<Sub>2</Sub>@PDA/PMAUPy JNs纳米片,并以其为添加剂成功制备了具有优良机械强度和自修复性能的纳米复合水凝胶。(The invention discloses a method for constructing self-repairing nano composite hydrogel by using prepared Janus nanosheets, which comprises the steps of firstly preparing silicon dioxide nano hollow Spheres (SiO) by using an emulsion method 2 JSs), then grinding the outer surface of the substrate after being adhered with agglomerated dopamine to prepare Janus @ PDA nano-sheets, and preparing SiO with double self-repairing performance by modifying and grafting polyisocyanoethyl methacrylate on the other side of the substrate by utilizing free radical polymerization 2 The @ PDA/PMAUPy JNs nanosheet is used as an additive to successfully prepare the nano composite hydrogel with excellent mechanical strength and self-repairing performance.)

1. A method for preparing self-repairing hydrogel by using a modified Janus nanosheet is characterized by comprising the following two steps: (1) preparation of silica-based Janus nanosheets (SiO) with Polydopamine (PDA) on one side and polyisocyanoethyl methacrylate (PMAUPy) once₂@ PDA/PMAUPy JNs) and is prepared through emulsion process to prepare hollow nano-silica Spheres (SiO)₂JSs) taking ethyl orthosilicate as a raw material, adding an aqueous solution of a styrene maleic anhydride copolymer (HSMA), deionized water, n-dodecane, 3- (methacryloyloxy) propyltrimethoxysilane and aminopropyltrimethoxysilane, wherein the mass ratio of the HSMA to the deionized water is that the ethyl orthosilicate to the n-dodecane to the 3- (methacryloyloxy) propyltrimethoxysilane to the aminopropyltrimethoxysilane =1 ~ 100 to 1 ~ 100 to 1 ~ 20 to 1 ~ 20 to 0.1 ~ 10 to 0.1 ~ 10,

the reaction temperature is 10 ~ 100 degrees centigrade,

the reaction time is 8 ~ 16 hours and 16 hours,

the reaction stirring speed is 100 ~ 600 rpm;

secondly, the silicon dioxide nanometer hollow Sphere (SiO) is utilized₂JSs) preparation of SiO₂@ PDA JNs nanosheets, preparation of SiO product₂JSs dispersing the nano material in deionized water under high-speed stirring, dropwise adding dopamine hydrochloride (DA) and Tris-HCl buffer solution (pH = 8.5) for self-polymerization, and centrifuging, crushing and drying the product to obtain a Janus @ DA nanosheet, wherein the mass ratio of DA: Tris-HCl buffer: SiO2₂JSs nanomaterial =1 ~ 10:1 ~ 10: 10 ~ 100,

the reaction temperature is 15 ~ 40 ℃,

the reaction time was 4 ~ 30 hours,

the reaction stirring speed is 100 ~ 600 rpm;

finally, the other side is grafted with PMAUPy polymer by free radical polymerization to prepare SiO₂@ PDA/PMAUPy JNs nanosheets, wherein the polymerization system comprises SiO₂@ PDAJNS nanosheets, hydrogen bond type monomers (MAUPy), Azobisisobutyronitrile (AIBN), and Dimethylformamide (DMF), wherein SiO is added according to the mass ratio₂@ PDA JNs nanosheets MAUPy: AIBN: DMF = 0.01 ~ 10:0.01 ~ 10:0.001 ~ 1:1 ~ 100;

the reaction temperature is 10 ~ 100 ℃;

the reaction time is 4 ~ 30 hours;

the reaction stirring speed is 100 ~ 600 rpm;

(2) using designed SiO₂@ PDA/PMAUPy JNs sodiumThe self-repairing nano composite hydrogel prepared from rice flakes comprises the following components in percentage by mass: acrylic acid, water, potassium persulfate solution, ferric chloride hexahydrate and SiO₂@ PDA/PMAUPyJNs =1 ~ 10:1 ~ 20:0.01 ~ 0.1.1: 0.01 ~ 0.1.1: 0.001 ~ 1, drying the prepared hydrogel, and then performing self-repairing performance measurement such as microscopy, stretching, rheology, swelling, scanning electron microscopy and the like, and exploring SiO₂The influence of the @ PDA/PMAUPy JNS nano-sheet on the self-repairing capability and mechanical strength of the hydrogel and the optimal dosage,

the reaction temperature is 30 ~ 100 ℃ and 100 ℃,

the reaction time was 2 ~ 24 hours,

the reaction stirring speed is 100 ~ 600 rpm.

2. A self-healing nanocomposite hydrogel capable of both rapid self-healing and high mechanical strength at room temperature prepared by the modified Janus nanosheets of claim 1.

Technical Field

The invention adopts an emulsion methodPreparing silicon dioxide nanometer hollow Sphere (SiO)₂JSs) and modifying and crushing the nano-particles to prepare and design a silicon dioxide based Janus nano-Sheet (SiO) with self-repairing functional groups on both sides₂@ PDA/PMAUPy JNs) as an additive to successfully construct a nano composite hydrogel with efficient self-repairing performance, belonging to the field of functional polymers.

Background

As a hydrophilic material with a network structure, most of the hydrogel has good biocompatibility, irritation and high water-bearing property. It is these special properties that make it have important application prospects in the fields of biomedicine, tissue engineering, chemical industry, etc. However, the disadvantages of low strength, low mechanical properties, and fragile structure limit the development of the composite material. The novel bionic material self-repairing hydrogel has excellent self-repairing performance, high strength and toughness, so that the service life of the hydrogel is prolonged, and extensive research is initiated.

Many methods have been proposed for preparing self-healing hydrogels, and strategies for reconstructing the damaged network structure of hydrogels include the use of healing agents, dynamic covalent bonds, or reversible non-covalent interactions such as hydrogen bonding, electrostatic interaction, and pi-pi stacking, among others. Recently, the development of novel self-repairing hydrogels has become one of the hot spots of the current research. The current novel design process types of the self-repairing hydrogel comprise nano-composite, double-network, polyelectrolyte and the like. The nano composite hydrogel has excellent self-repairing, high strength and toughness performances. A great deal of previous research into nanocomposite self-healing hydrogels has focused on nanocomposites, and nanocomposite hydrogels reinforced with nanoclays, silica nanoparticles, carbon nanotubes and Graphene Oxide (GO) have been reported.

Whereas Janus materials are unique among these nanocomposites. Janus nano material refers to a special nano material with an asymmetric structure or property, and can be asymmetric in shape or composition property of the nano material. In terms of appearance, the asymmetric appearance enables the Janus nano material to have a special space effect, and can be used for discussing target recognition, self-assembly and the like; from the composition property, the Janus material can simultaneously have two different or even opposite properties, such as hydrophile-hydrophobicity, positive charge-negative charge, polarity-nonpolarity, magnetism-non-magnetism and the like, so that the material has multiple functions and can simultaneously adapt to more complex condition requirements. In view of the consideration, in recent years, there is a wide prospect in trying to design and prepare multi-component and multifunctional asymmetric Janus materials and researching their application in the aspects of physics, chemistry, biology, catalysis, optical imaging, drug transportation and the like, which plays a crucial role in promoting the development of new materials.

The invention designs and prepares SiO with double self-repairing performance₂@ PDA/PMAUPy JNs nanosheets and SiO₂The @ PDA/PMAUPy JNs nanosheet is used as a strong additive, can be doped into a polyacrylic acid network through free radical polymerization reaction, and is used as a physical cross-linking agent to further improve the cross-linking degree of the polyacrylic acid network. Therefore, the nano-composite hydrogel with high mechanical strength and repair rate is prepared, a new thought is provided for preparing the self-repairing hydrogel, and the nano-composite hydrogel has a good prospect in the fields of biomedicine and the like.

Disclosure of Invention

The invention aims to provide a method for preparing self-repairing hydrogel based on a silicon dioxide-based Janus nanocomposite.

In order to achieve the purpose, the specific technical scheme of the invention is as follows:

(1) preparation of silica-based Janus nanosheets (SiO) with Polydopamine (PDA) on one side and polyisocyanoethyl methacrylate (PMAUPy) once₂@ PDA/PMAUPy JNs) and is prepared through emulsion process to prepare hollow nano-silica Spheres (SiO)₂JSs) taking ethyl orthosilicate as a raw material, adding an aqueous solution of a styrene maleic anhydride copolymer (HSMA), deionized water, n-dodecane, 3- (methacryloyloxy) propyltrimethoxysilane and aminopropyltrimethoxysilane, wherein the mass ratio of the HSMA to the deionized water is that the ethyl orthosilicate to the n-dodecane to the 3- (methacryloyloxy) propyltrimethoxysilane to the aminopropyltrimethoxysilane =1 ~ 100 to 1 ~ 100 to 1 ~ 20 to 1 ~ 20 to 0.1 ~ 10 to 0.1 ~ 10,

the reaction temperature is 10 ~ 100 degrees centigrade,

the reaction time is 8 ~ 16 hours and 16 hours,

the reaction stirring speed is 100 ~ 600 rpm;

secondly, the silicon dioxide nanometer hollow Sphere (SiO) is utilized₂JSs) preparation of SiO₂@ PDA JNs nanosheets, preparation of SiO product₂JSs the nano material is dispersed in deionized water under high speed stirring, and dopamine hydrochloride (DA) and Tris-HCl buffer solution (pH = 8.5) are added dropwise for self-polymerization. And centrifuging, crushing and drying the product to obtain the Janus @ DA nanosheet. Wherein, according to the mass ratio, DA: Tris-HCl buffer: SiO2₂JSs nanomaterial =1 ~ 10:1 ~ 10: 10 ~ 100,

the reaction temperature is 15 ~ 40 ℃,

the reaction time was 4 ~ 30 hours,

the reaction stirring speed is 100 ~ 600 rpm;

finally, the other side is grafted with PMAUPy polymer by free radical polymerization to prepare SiO₂@ PDA/PMAUPy JNs nanosheets, wherein the polymerization system comprises SiO₂@ PDA JNs nanosheets, hydrogen bond monomer (MAUPy), Azobisisobutyronitrile (AIBN), Dimethylformamide (DMF). Wherein, according to the mass ratio, SiO₂@ PDA JNs nanosheets MAUPy: AIBN: DMF = 0.01 ~ 10:0.01 ~ 10:0.001 ~ 1:1 ~ 100;

the reaction temperature is 10 ~ 100 ℃;

the reaction time is 4 ~ 30 hours;

the reaction stirring speed is 100 ~ 600 rpm;

(2) using designed SiO₂The self-repairing nano composite hydrogel is prepared from @ PDA/PMAUPy JNs nanosheets, wherein the self-repairing nano composite hydrogel comprises the following components in percentage by mass: acrylic acid, water, potassium persulfate solution, ferric chloride hexahydrate and SiO₂@ PDA/PMAUPyJNs =1 ~ 10:1 ~ 20:0.01 ~ 0.1.1: 0.01 ~ 0.1.1: 0.001 ~ 1, drying the prepared hydrogel, and then performing self-repairing performance measurement such as microscopy, stretching, rheology, swelling, scanning electron microscope, and the like₂Shadow of @ PDA/PMAUPy JNS nanosheet on hydrogel self-repairing capability and mechanical strengthThe noise and the optimal dosage are reduced,

the reaction temperature is 30 ~ 100 ℃ and 100 ℃,

the reaction time was 2 ~ 24 hours,

the reaction stirring speed is 100 ~ 600 rpm.

Accordingly, the present invention claims a method of self-healing hydrogels. The method comprises the following steps:

(1) a formulation system as defined in claim 1 (1);

(2) the prepared SiO₂The @ PDA/PMAUPy JNS nanosheet is added into the preparation process of the hydrogel taking acrylic acid as a matrix, so that self-repairing of hydrogen bonds and metal-ligand synergistic effect is realized.

Due to the application of the scheme, compared with the prior art, the invention has the advantages that:

the high-efficiency dual self-repairing hydrogel is prepared by modifying the Janus nanosheets under the synergistic effect of hydrogen bonds and metal-coordination bonds, and meanwhile, the mechanical strength and the self-repairing rate of the hydrogel are improved.

Detailed Description

The invention is further described below with reference to exemplary embodiments, but the invention is not limited to the following embodiments. The method is a conventional method unless otherwise specified. The starting materials are commercially available from the open literature unless otherwise specified.

Example (a): preparation of hollow silica nanospheres (SiO 2 JSs)

15 mL of a styrene-maleic anhydride copolymer aqueous solution and 75 mL of ultrapure water were uniformly mixed, and the pH of the aqueous solution was adjusted to 2.5 with 2 mol/L hydrochloric acid to prepare an aqueous phase. 5.6 mL of ethyl orthosilicate, 10.4 mL of n-heptane, 1.0mL of 3- (methacryloyloxy) propyltrimethoxysilane, and 1.2 mL of aminopropyltrimethoxysilane were mixed uniformly to prepare an oil phase for later use. The aqueous phase and the oil phase are mixed and homogenized to form a stable oil-in-water emulsion. The liquid is placed at 70 ℃ and stirred mechanically for 12 hours.

Example (b): preparation of Janus @ DA nanosheet

The pH was adjusted to around 8.0 with an aqueous solution of Tris-hydroxymethyl aminomethane (Tris-H2O). 50 mL of dopamine hydrochloride solution in Tris-HCl (2 mg/mL) was added with stirring, and the reaction was stirred at room temperature for 24 hours. The above solution was centrifuged and then washed 3 times with absolute ethanol. And (3) dispersing the brown solid in absolute ethyl alcohol, crushing for 7 days by using a cell crusher, and then centrifuging and drying in vacuum to obtain the Janus @ DA nanosheet.

Example (iii): preparation of SiO₂@ PDA/PMAUPy JNs nanosheet

Weighing 0.2 g of Janus @ DA nanosheet and 0.2 g of hydrogen bond type monomer (MA-UPy) in an ampoule bottle, adding 0.01 g of azobisisobutyronitrile and 4 mL of Dimethylformamide (DMF), introducing nitrogen for 10 min, heating to 70 ℃, stirring for reacting for 12 hours, centrifuging the obtained product, washing with absolute ethyl alcohol, and drying in an oven to obtain SiO₂@ PDA/PMAUPy JNs nanosheets.

Example (iv): preparation of self-repairing hydrogel

Taking 2.5 mL of acrylic acid, 5 mL of water, 2.5 mL of potassium persulfate solution, 0.8 mL of FeCl3.6H2O and 5 mg of modified Janus nanosheets, reacting in a constant-temperature magnetic stirrer at 60 ℃ for about 20 min, pouring the liquid into a specific mold when the liquid becomes very viscous, putting the mold into a drying oven at 35 ℃ to evaporate the solvent, and then carrying out self-repairing performance determination on the prepared hydrogel such as microscopy, stretching, rheology and the like. Different hydrogels are prepared by controlling the types and the use amounts of the modified Janus nanosheets, and SiO is explored₂The influence of the @ PDA/PMAUPy JNS nanosheets on the self-repairing capability and mechanical strength of the hydrogel is further utilized, so that the self-repairing hydrogel with the optimal performance is found out.