阅读说明：本技术 一种新型核壳结构的彩色二氧化硅及其制备方法和应用 (Novel core-shell structure colored silicon dioxide and preparation method and application thereof ) 是由 杨荟 埃泽尔·阿金诺古 金名亮 王新 水玲玲 米夏埃尔·吉尔斯西 保罗·穆尔瓦尼 于 2020-07-23 设计创作，主要内容包括：本发明属于染料掺杂二氧化硅制备技术领域,公开了一种新型核壳结构的彩色二氧化硅,所述彩色二氧化硅以二氧化硅为核,以PDADMAC-染料预混物为内壳层,以二氧化硅为外壳层；本发明将PDADMAC作为一个连接负电性的二氧化硅颗粒与带有负电官能团染料分子的桥梁,成功的将染料分子包裹在二氧化硅颗粒表面；随后再次在PDADMAC-染料预混物外包裹一层二氧化硅作为外壳层,从而最终制得新型核壳结构的彩色二氧化硅；该新型核壳结构的彩色二氧化硅性质稳定,染料不易泄露；本发明的制备方法制得的新型核壳结构的彩色二氧化硅颗粒均一,可以广泛应用于催化、分子检测、生物监测、成像等领域。(The invention belongs to the technical field of dye-doped silicon dioxide preparation, and discloses a novel core-shell-structured colored silicon dioxide, which takes silicon dioxide as a core, PDADMAC-dye premix as an inner shell layer, and silicon dioxide as an outer shell layer; the invention takes PDADMAC as a bridge for connecting electronegative silicon dioxide particles and dye molecules with electronegative functional groups to successfully wrap the dye molecules on the surfaces of the silicon dioxide particles; then wrapping a layer of silicon dioxide outside the PDADMAC-dye premix as a shell layer, thereby finally preparing the novel core-shell structure colored silicon dioxide; the color silicon dioxide with the novel core-shell structure is stable in property, and the dye is not easy to leak; the novel core-shell structure color silica particles prepared by the preparation method disclosed by the invention are uniform, and can be widely applied to the fields of catalysis, molecular detection, biological monitoring, imaging and the like.)

1. The novel color silica with the core-shell structure is characterized in that the color silica takes silica as a core, PDADMAC-dye premix as an inner shell layer and silica as an outer shell layer.

2. The novel core-shell structured colored silica according to claim 1, wherein the dye contains a negatively charged functional group.

3. The method for preparing the novel core-shell structure colored silica according to claim 1 or 2, comprising the following steps:

s1, dissolving dye molecules with negative electricity functional groups, and mixing the dye molecules with the negative electricity functional groups with PDADMAC to obtain a PDADMAC-dye premix;

s2, dropwise adding the PDADMAC-dye premix prepared in the S1 into a silicon dioxide particle aqueous solution to enable silicon dioxide particles to fully absorb the PDADMAC-dye premix, so as to obtain colored silicon dioxide particles with positive charges on the surfaces;

and S3, coating a silicon dioxide shell layer on the surface of the colored silicon dioxide particles with positive charges by adopting a conventional method.

4. The method for preparing novel core-shell structure colored silica according to claim 3, wherein the ratio of the dye to the PDADMAC used in step S1 is 1-2 x 10^-6M：3mg。

5. The method for preparing novel core-shell structure color silica according to claim 3, wherein the mixing time of the dye and PDADMAC in step S1 is more than 20 min.

6. The method for preparing novel core-shell structure colored silica according to claim 3, wherein step S1 employs silica particle solution

7. The method for preparing novel core-shell structure color silica according to claim 3, wherein the mixing ratio of the PDADMAC-dye premix and the silica particle solution in step S2 is 0.3-2 x 10^-6M：100mg。

8. The preparation method of the novel core-shell structure colored silica according to claim 3, wherein the thickness of the silica outer shell layer in step S3 is 5-20 nm.

9. Use of the novel core-shell structured coloured silica according to claim 1 or 2.

10. The use according to claim 9, wherein the fields of application include, but are not limited to, photocatalytic degradation, bio-imaging, sensor detection.

Technical Field

The invention relates to the technical field of preparation of dye-doped silicon dioxide, and particularly relates to novel core-shell-structured colored silicon dioxide and a preparation method and application thereof.

Background

Compared with free dye, the dye-doped silicon dioxide particles have the characteristics of better light stability, water solubility, low toxicity and easy surface modification, so the dye-doped silicon dioxide particles have wide application prospect in biological imaging and sensor technology. Several methods have been developed to incorporate luminescent dyes into silica matrices to produce dye-doped silica particles.

Fluorescent nanoparticles were first obtained in 1992 by Van Blaaderen et al, which first prepared Fluorescein Isothiocyanate (FITC) doped silica nanoparticles by covalent coupling. In this reaction, FITC and 3-Aminopropyltriethoxysilane (APTES), a silane coupling agent, were first coupled in the dark and nitrogen environment for 24 hours to give a FITC-APTES conjugate. Then, taking ammonia water as a catalyst, and carrying out catalytic hydrolysis and condensation on the FITC-APTES conjugate and a silicon source TEOS in an ethanol environment by using the ammonia water to obtain the fluorescent nanoparticles. In using this method, care must be taken that the fluorescent dye must have a functional group capable of coupling with the amino group of the silane coupling agent. However, the current functional group fluorescent dyes capable of reacting with amino are few in types and expensive, and the application of the method is greatly limited.

In 2005, the Rosenzweig group was first at

Phenanthroline ruthenium is doped into an amorphous silicon dioxide medium in a reaction system, so that silicon dioxide particles which are controllable in size, good in light stability and almost free of dye leakage are obtained. The method is based on electrostatic attraction between a positively charged organometallic dye and a negatively charged silica backbone. This method is simpler than the covalent coupling method. However, the metal organic dyes are less in variety and cannot meet a large demand. According to Liang et al a novel adsorption method is proposed, since most water-soluble dyes are negatively charged, while

The silica particles obtained by the synthesis method have a large amount of negative charges due to hydroxyl groups on the surface, and it has been found that polydimethyldiallylammonium chloride (PDADMAC) is a long-chain water-soluble polymer chemical having a large number of positive charges for linking the silica particles to a negatively charged dye, and the dye can be adsorbed into the silica particles by electrostatic force adsorption. However, this method has an effect on the uniformity of the silica particles; tan group prepared 63. + -. by electrostatic interaction in 20014nm bipyridine ruthenium doped silica nanoparticles. However, the synthesis system by reverse microemulsion method is carried out in the environment of aqueous solution, because the water-soluble dye usually has negative charges, such as hydroxyl, carboxyl and sulfonate. Since these groups have the same negative charge as the silica matrix, the dye is hardly bound, and thus the bleeding phenomenon is very serious.

By summarizing the above-mentioned methods, people find useThe covalent coupling of the system must be performed by adding a surface functional group to a specific dye or by using a catalyst to promote the condensation reaction of the original functional group with an amino group, so that the conjugate of the dye and APTES can be cohydrolyzed with TEOS to prepare doped silica particles. Research shows that the dye with specific functional group has less molecules and high price, and is not suitable for large-scale application. For electrostatic adsorption, the method can simply pack the negative charge dye into the silica particles, but because of the charging property, the uniformity of the silica particles can be affected, the generated silica particles are aggregated, and controllable and uniform doped silica particles are difficult to obtain. For the reverse microemulsion method, the method is not considered here because the controllable range of particle size is small and the dye is very easily leaked.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the silicon dioxide particles which are low in cost, simple in preparation process, easy in raw material obtaining, controllable in size and capable of forming monodispersed and uniform dye doping.

The invention mainly aims to provide a novel core-shell structure colored silica.

The second purpose of the invention is to provide a preparation method of the color silicon dioxide with the novel core-shell structure.

The third purpose of the invention is to provide the application of the colored silicon dioxide with the novel core-shell structure.

The purpose of the invention is realized by the following technical scheme:

the novel color silicon dioxide with a core-shell structure takes silicon dioxide as a core, takes PDADMAC-dye premix as an inner shell layer and takes silicon dioxide as an outer shell layer.

PDADMAC (poly dimethyl diallyl ammonium chloride) is a strong cationic polyelectrolyte with a colorless to pale yellow viscous liquid appearance. Safe, nontoxic, easily soluble in water, non-flammable, strong cohesive force, good hydrolytic stability, no gel formation, insensitivity to pH value change and chlorine resistance. The invention utilizes the property that PDADMAC is easily dissolved in water and strong cationic polyelectrolyte to be used as a bridge for connecting electronegative silicon dioxide particles and dye molecules with electronegative functional groups. Successfully coating dye molecules on the surface of the silica particles; on one hand, the dye molecules are further protected from leakage, and on the other hand, the surface of the silicon dioxide nano particle material is easy to modify; wrapping a layer of silicon dioxide outside the PDADMAC-dye premix as a shell layer, thereby finally preparing the novel core-shell structure colored silicon dioxide; the novel color silicon dioxide with the core-shell structure is stable in property, dye is not easy to leak, the intensity of a reflection peak is remarkably increased due to the fine scattering characteristic of the silicon dioxide to visible light, and composite particles are brighter than organic pigment due to the existence of the shell layer silicon dioxide.

Preferably, the dye contains a negatively charged functional group.

More preferably, the negatively charged functional group is a sulfonic acid group.

The invention utilizes the electrostatic adsorption method of PDADMAC, but changes the idea that the dye is not considered to be wrapped, but the dye is considered to be wrapped on the surface of the silicon dioxide particles to form the colorful silicon dioxide particles with the core-shell structure. In the early days of market research, most dyes on the market have negative electric functional groups. However, it should be noted that the stronger the chargeability of the negative electron energy groups, the better the adsorption effect, so that dye molecules having negative electron energy groups with sulfonic acid groups are selected here. PADAMAC is used as a bridge to connect silica particles with dye molecules with sulfonic acid groups, and then a layer of silicon shell is wrapped, so that the aims of protecting the dye molecules and further applying the dye molecules are fulfilled.

Drawings

FIG. 1 is a schematic diagram of a process for preparing a novel core-shell structured colored silica;

FIG. 2 is a flow chart of the preparation of a novel core-shell structured colored silica;

FIG. 3 is the variation of the surface potential of the particle with the dye/shell coating and the study of the maximum adsorption using the potential;

FIG. 4 shows an absorption spectrum of a direct blue 71 aqueous solution and a reflection spectrum of blue silica particles having a core-shell structure;

FIG. 5 is a silica particle size statistic after wrapping the PDADMAC-dye premix and after wrapping the silica outer shell layer; the first row is SEM picture, the second row is particle size distribution statistical chart.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.