CN110591089A

CN110591089A - Preparation method of micro/nano core-shell structure Si @ PDA

Info

Publication number: CN110591089A
Application number: CN201910795610.8A
Authority: CN
Inventors: 张文超; 吴刚刚; 陈亚杰; 郑子龙; 秦志春; 宋长坤; 陈浩
Original assignee: Nanjing Tech University
Current assignee: Nanjing Tech University
Priority date: 2019-08-27
Filing date: 2019-08-27
Publication date: 2019-12-20
Anticipated expiration: 2039-08-27
Also published as: CN110591089B

Abstract

The invention discloses a preparation method of Si @ PDA with a micro/nano core-shell structure. According to the method, under the condition of room temperature, dopamine hydrochloride is firstly adsorbed on micro/nano Si particles in an organic system, then a layer of PDA film is uniformly coated on the surface of Si through oxidation and auto-polymerization, and a large number of amino, phenolic hydroxyl and other functional groups exist on the surface of the film, so that secondary assembly modification is facilitated. The method adopts a pure organic solvent system, has mild reaction conditions, inhibits the oxidative inactivation in the coating process of the high-activity micro/nano Si powder, and does not need low-temperature environments such as ice bath and the like; the method can achieve the surface functional modification of the micro/nano Si powder and provide an ideal platform for secondary modification, and can not influence the mass transfer process among the components of the assembled silicon-based energetic material.

Description

Preparation method of micro/nano core-shell structure Si @ PDA

Technical Field

The invention belongs to the technical field of preparation of micro/nano energetic materials, and relates to a preparation method of micro/nano core-shell structure Si @ PDA.

Background

Compared with aluminum-based energetic materials, the silicon-based energetic material has the following advantages: (1) the theoretical heat value of combustion of silicon is high (7.750kcal g)^-1Al is 7.422kcal g^-1) The thermochemical performance is good; (2) the surface oxide layer is thinner (about 1nm, the Al surface oxide layer is 2-6nm), which is beneficial to high activity maintenance; (3) the silicon-based energetic material has good antistatic capability; (4) the silicon surface is easy to be functionally modified. Therefore, the silicon-based energetic material has important application prospect.

The surface modification of the material is adopted, so that the material surface is multifunctional, which is a great research hotspot at present. The preparation, functionalization and application of Dopamine (DA) -based nanomaterials has attracted extensive attention since Lee et al (Lee H, Dellatre S M, Miller W M, Messersmith P B. science,2007,318:426) reported methods of preparing Polydopamine (PDA) coating materials. A layer of polydopamine film with extremely strong adhesion can be formed on the surface of the material by the oxidation auto-polymerization of dopamine, and a large amount of amino (-NH) exists on the surface of a substrate modified by dopamine₂) Functional groups such as imino (-NH-), catechol and the like, and the functional groups can generate Michael addition reaction and Schiff base reaction under certain environmental conditions, thereby increasing the complexing ability and the reducing ability of the matrix material and providing more adsorption sites. In addition, the catechol structure can anchor metal ions on the surface of the material through chelation under mild conditions, and secondary modification is facilitated. Therefore, the coating PDA film can provide an ideal platform for secondary modification and multi-functionalization of the material surface. Ou et al (Ou J F, Wang J Q, Zhang D, Zhang P L, Liu S, Yan P H, Liu B, Yang S R.Collioids.Surf.B,2010,76:123) coat the surface of a silicon wafer with a layer of 3-aminopropyltriethoxysilane, then coat a dopamine coating (PDAc) as an intermediate layer, and finally perform secondary modification to prepare a novel three-layer organic film, wherein the method coats PDA by using water as a solvent. Research shows that (FOzanam. JN Chazalviel. J. electroananal. chem.1989, 251-266; Zhonggen, Yi-shi-zhou-qin, Zhou-lang. electronic components and materials, 2018,27:10), water is an important factor causing silicon powder oxidation,therefore, in the above method, water is used as a solvent, so that the silicon wafer therein is easily reacted with water to be oxidized, thereby affecting the performance of the material.

Disclosure of Invention

The invention aims to provide a preparation method of micro/nano core-shell structure Si @ PDA. In the method, a layer of PDA film is uniformly coated on the surface of the micro/nano silicon powder in an organic system, and the micro/nano silicon powder coated with PDA is a micro/nano core-shell structure Si @ PDA.

The technical solution for realizing the purpose of the invention is as follows:

the preparation method of the micro/nano core-shell structure Si @ PDA comprises the following specific steps:

dissolving tris (hydroxymethyl) aminomethane or barbituric sodium in an organic solvent, adjusting the pH value with hydrochloric acid, adding dopamine hydrochloride (DA), stirring until the dopamine hydrochloride is completely dissolved, finally adding micro/nano Si powder, performing ultrasonic dispersion uniformly, stirring for oxidation self-polymerization reaction, performing suction filtration, cleaning with methanol, and drying to obtain the micro/nano core-shell structure Si @ PDA.

Preferably, the organic solvent is selected from one or two of methanol, ethanol, Dimethylformamide (DMF) and acetonitrile.

Preferably, the pH is 6.8-9.6.

Preferably, the concentration of the DA is 1-3 mg/mL.

Preferably, the concentration of the micro/nano Si powder is 1-2 mg/mL.

Preferably, the time of the oxidative self-polymerization reaction is 1-10 h.

Compared with the prior art, the invention has the following advantages:

(1) the reaction condition is mild, and the thickness of the PDA coating layer is controllable; the method can not only achieve the surface functional modification of the micro/nano Si powder and provide an ideal platform for secondary modification, but also cannot influence the mass transfer process among the components of the assembled silicon-based energetic material;

(2) compared with water and aqueous solution, the silicon powder has relatively small oxidation degree in an organic solvent and has a certain protection effect on the oxidation of silicon powder.

Drawings

FIG. 1 is a schematic diagram of the preparation method of the present invention.

FIG. 2 is an XRD spectrum of pure phase n-Si and n-Si @ PDA from example 2.

FIG. 3 is an FTIR spectrum of pure phase n-Si and n-Si @ PDA from example 2.

FIG. 4 is a TEM image of pure phase n-Si and n-Si @ PDA from example 2.

Detailed Description

The present invention will be described in further detail with reference to the following examples and accompanying drawings.

Example 1

The preparation method of the core-shell structure m-Si @ PDA comprises the following specific steps:

step 1, measuring 100mL of methanol and DMF (volume ratio of 1: 1) respectively, placing the methanol and the DMF in a 500mL beaker, weighing 0.24g of Tris, stirring the Tris until the Tris is completely dissolved, and then dropwise adding hydrochloric acid to adjust the pH value of a system to 7.5;

step 2, weighing 0.4g of dopamine hydrochloride, and stirring at normal temperature to completely dissolve the dopamine hydrochloride;

and 3, weighing 0.2g of micron Si powder (m-Si), carrying out ultrasonic treatment for 10min to uniformly disperse the micron Si powder, stirring and reacting for 5h at normal temperature, carrying out suction filtration, washing methanol for several times, and drying.

Example 2

The preparation method of the core-shell structure n-Si @ PDA comprises the following specific steps:

step 1, measuring 100mL of methanol and DMF (volume ratio of 1: 1) respectively, placing the methanol and the DMF in a 500mL beaker, weighing 0.24g of Tris, stirring the Tris until the Tris is completely dissolved, and then dropwise adding hydrochloric acid to adjust the pH value of a system to 8.5;

and 3, weighing 0.2g of nano Si powder (n-Si), carrying out ultrasonic treatment for 10min to uniformly disperse the nano Si powder, stirring and reacting for 5h at normal temperature, carrying out suction filtration, washing methanol for several times, and drying.

Example 3

Characterization by XRD

Taking an n-Si @ PDA sample as an example, FIG. 2 is an XRD spectrum of the corresponding sample. Comparing with the standard card JCPDS27-1402 of Si, it can be seen that the crystal form of pure phase nano Si powder is not changed before and after the PDA coating.

Characterization by FTIR

Taking n-Si @ PDA sample as an example, FIG. 3 is an FTIR spectrum of the corresponding sample. Compared with pure-phase Si powder, the FTIR spectrum of the Si powder coated with PDA has-NH₂The characteristic peaks of-NH-and benzene ring indicate that PDA is successfully coated on the surface of Si powder.

TEM characterization

Taking an n-Si @ PDA sample as an example, FIG. 4 is a TEM spectrum of the corresponding sample. Compared with pure-phase Si powder, the surface of the coated Si powder has a PDA layer with the thickness of 3-5 nm.

Claims

1. The preparation method of the micro/nano core-shell structure Si @ PDA is characterized by comprising the following specific steps:

dissolving tris (hydroxymethyl) aminomethane or barbituric sodium in an organic solvent, adjusting the pH value with hydrochloric acid, adding dopamine hydrochloride, stirring until the dopamine hydrochloride is completely dissolved, finally adding micro/nano Si powder, performing ultrasonic dispersion uniformly, stirring for performing oxidation self-polymerization reaction, performing suction filtration, cleaning with methanol, and drying to obtain the micro/nano core-shell structure Si @ PDA.

2. The method according to claim 1, wherein the organic solvent is one or two selected from methanol, ethanol, dimethylformamide and acetonitrile.

3. The method according to claim 1, wherein the pH is 6.8 to 9.6.

4. The preparation method according to claim 1, wherein the concentration of dopamine hydrochloride is 1-3 mg/mL.

5. The preparation method according to claim 1, wherein the concentration of the micro/nano Si powder is 1-2 mg/mL.

6. The preparation method according to claim 1, wherein the time of the oxidative autopolymerization reaction is 1 to 10 hours.