CN107022083B

CN107022083B - Silicon-based hyperbranched conjugated polymer and preparation method thereof

Info

Publication number: CN107022083B
Application number: CN201710254469.1A
Authority: CN
Inventors: 崔月芝; 吴洪涛; 马晓双; 陶芙蓉; 李天铎
Original assignee: Qilu University of Technology
Current assignee: Qilu University of Technology
Priority date: 2017-04-18
Filing date: 2017-04-18
Publication date: 2020-11-13
Anticipated expiration: 2037-04-18
Also published as: CN107022083A

Abstract

The invention discloses a silicon-based hyperbranched conjugated polymer and a preparation method thereof, wherein the hyperbranched conjugated polymer is formed by polymerizing a plurality of branching units, and the number average molecular weight of the hyperbranched conjugated polymer is 3-6 multiplied by 10⁴ g·mol^‑1The molecular weight distribution index is 1.05-1.50, each branching unit takes eight (3-mercaptopropyl) -three-dimensional cage-like silsesquioxane (POSS) as a core compound, and the tail end mercapto group of the core compound is connected with poly- (dihalo-methylphenyl silane-co-dihalo-diphenylsilane). The hyperbranched polymer is characterized in that: 1) the composite material has a three-dimensional pore structure, and the permeability and the specific surface area of the nitroaromatic are increased; 2) electropositive property (⁺) The weak non-covalent interaction between the silicon atom of (a) and the nitrogen or oxygen atom of the nitroarene can effectively enrich the nitroarene molecules.

Description

Silicon-based hyperbranched conjugated polymer and preparation method thereof

Technical Field

The invention belongs to the technical field of polymer synthesis and fluorescent sensing materials, and particularly relates to a silicon-based hyperbranched conjugated polymer taking polyhedral oligomeric silsesquioxane (POSS) as a core and polysilane as a side chain and a preparation method thereof.

Background

The on-line detection of explosives is mainly a technology for detecting vapor volatilized by explosives and trace explosives remained on the surface of an explosive container and the surface of any article (including a human body) contacted with the explosives. Concealed explosives may form trace concentrations within a certain range around them. Buried mines with PVC casings have been reported to have TNT, DNT levels in the earth surface of up to 0.15ppb over time. The fluorescence sensing method has the characteristics of high sensitivity, more collectable parameters (such as fluorescence intensity, fluorescence spectrum morphology, fluorescence anisotropy, fluorescence lifetime and the like), quick response time, relatively mature instrument design and the like, and becomes a detection method with development prospect.

A large number of fluorescent sensing materials for detecting NACs explosives have been reported, but most are organic pi-pi conjugated polymers (OCPs). The skeleton of the OCP can be used as a molecular wire, so that excitons can rapidly migrate along a polymer chain, and a signal amplification effect of one-point contact and multi-point response is generated. However, in solid films, the OCP tends to accumulate through pi-pi interactions between the polymer backbones. This pi-pi stacking leads to two disadvantages, limiting their application in chemical sensors: 1) fluorescence self-quenching phenomena caused by energy transfer between polymer backbones; 2) the main chain of the OCP tends to be rigid, resulting in poor solubility in common solvents and difficulty in processing and utilization.

Polysilanes are a new inorganic conjugated polymeric material that has emerged in recent years. The main chain of the polymer is composed of Si-Si, and the polymer is obviously different from rigid conjugated polymers composed of C ═ C and aromatic rings in properties. Firstly, a molecular main chain formed by Si-Si bonds is a flexible chain, so that the solubility is good, and the processing is easy; secondly, the small electronegativity and the empty 3d orbital of the Si atom enable the sigma electrons of the polysilane main chain to be delocalized widely along the Si-Si main chain, and a sigma conjugate effect is generated. Therefore, like OCP, polysilane also has a molecular wire effect and has better response sensitivity to nitroaromatic explosives. The flexible backbone of polysilanes, however, allows them to avoid fluorescence quenching similar to that produced by pi-pi stacking in OCP. Thirdly, the weak non-covalent interaction between the silicon atom with positive electric property (+) and the oxygen atom with negative electric property in the nitroarene can effectively enrich the nitroarene molecules and improve the response sensitivity. In conclusion, polysilane is a potential fluorescence sensing material for detecting nitroarene. However, when the pure polysilane is used as a fluorescent sensing material, molecular chains of the pure polysilane are tightly entangled, and the permeability is poor, so that the pure polysilane is not beneficial to the diffusion of molecules of the substance to be detected in the fluorescent sensing material.

Polyhedral oligomeric silsesquioxanes (POSS) are a nanocage molecule that can be modified with organic groups at the vertices of each silicon atom. Due to the characteristics of unique nano-size structure, high thermal stability, easy chemical modification and the like, POSS has proved to be an important 3D support for the construction of porous materials for various purposes. If the fluorescent sensing material is introduced into fluorescent sensing molecules, the permeability of the material can be greatly improved, and the sensing sensitivity is improved. At present, various methods for synthesizing compounds with POSS as a core and optical properties have been reported. The compound has a three-dimensional structure, can generate micro pores in molecules, has large specific surface of the material and good molecular permeability, and is beneficial to improving the sensitivity of the sensing material.

Therefore, the hyperbranched conjugated polymer for fluorescence analysis and detection of TNT and DNT is constructed by taking POSS as a core and polysilane as a side chain, has excellent sensing performance of polysilane and high permeability of POSS derivatives, and thus can show better comprehensive performance.

Disclosure of Invention

In view of the above prior art, the present invention aims to provide a hyperbranched fluorescent polymer (compound IV) having POSS as a core and polysilane as a side chain. The polysilane is of a sigma conjugated structure, has a molecular wire effect, and does not have fluorescence quenching caused by pi-pi accumulation; the three-dimensional POSS structure improves the permeation rate of molecules of a substance to be detected in the membrane, thereby improving the sensing sensitivity of the material.

The invention adopts the following technical scheme:

the invention provides a silicon-based hyperbranched conjugated polymer, which is formed by polymerizing a plurality of branching units, and the number average molecular weight of the hyperbranched conjugated polymer is 3-6 multiplied by 10⁴g·mol^-1The molecular weight distribution index is 1.05-1.50, each branching unit is a hyperbranched structure which takes three-dimensional eight (3-mercaptopropyl) -cage-type silsesquioxane (POSS) as a core and takes polysilane as a side chainThe terminal mercapto group of the core compound is connected with poly- (dihalo methyl phenyl silane-co-dihalo diphenyl silane).

The hyperbranched polymer has a micropore and mesopore structure, wherein the mesopore diameter is distributed between 2 nm and 55nm, and the main pore diameter is distributed between 15 nm and 20nm (preferably 17 nm). The polymer has rich pore structure, increases the specific surface area, improves the penetration rate of the nitroaromatic, and improves the detection sensitivity.

Further, the poly- (dihalomethylphenylsilane-co-dihalodiphenylsilane) block contained in the polymer of the present invention is a random polymer. Experiments prove that the polysilane paranitroarene has good fluorescence quenching performance and good solubility in common solvents.

Further, the poly- (dihalomethylphenylsilane-co-dihalodiphenylsilane) is poly- (dichloromethylphenylsilane-co-dichlorodiphenylsilane) or poly- (dibromomethylphenylsilane-co-dibromodiphenylsilane).

The second aspect of the present invention further provides a preparation method of the above silicon-based hyperbranched conjugated polymer, comprising the following steps:

the silicon-based hyperbranched conjugated polymer is synthesized by reacting octa (3-mercaptopropyl) POSS and poly (dihalo methyl phenyl silane-co-dihalo diphenyl silane) through mercapto-alkene click chemistry reaction.

In the invention, the reaction solvent adopted in the mercapto-alkene click chemistry reaction is anhydrous toluene.

In the invention, the radical initiator adopted in the mercapto-alkene click chemistry reaction is Azobisisobutyronitrile (AIBN).

In the invention, the reaction time for synthesizing the silicon-based hyperbranched conjugated polymer is 4-8 hours, and the further preferable reaction time is 4 hours; the reaction temperature is 60-80 ℃, and the preferable reaction temperature is 60 ℃.

In the invention, the reaction for synthesizing the silicon-based hyperbranched conjugated polymer is carried out under the condition of inert gas, and the inert gas can be argon or nitrogen. In the present invention, the mass ratio of the octa (3-mercaptopropyl) POSS, the vinyl copoly (dihalomethylphenylsilane-co-dihalodiphenylsilane) and the Azobisisobutyronitrile (AIBN) is 1.0:0.1 to 0.6:0.10 to 0.15, and a more preferable mass ratio is 1:0.6: 0.10.

In the present invention, some preferred embodiments specifically include the following steps:

in N₂Mixing octa (3-mercaptopropyl) POSS, AIBN and vinyl poly (dihalo methyl phenyl silane-co-dihalo diphenyl silane) in the environment, and heating in an oil bath; then the oil bath was removed and the solution was exposed to air; and recovering a precipitate product, washing with chloroform, combining the filtrates, standing overnight (8-16 h) at room temperature, and drying to obtain a white powdery compound IV.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

compared with the currently reported compound taking cage type silsesquioxane POSS as a core, the compound prepared by the invention is unique in that polysiloxane chromophores with sigma conjugate effect are functionally introduced at each vertex. The hyperbranched polymer is characterized in that: 1) the material has a three-dimensional pore structure, and the permeability and the contact area of the nitroaromatic are increased; 2) electropositive property (⁺) The weak non-covalent interaction between the silicon atom of (a) and the nitrogen or oxygen atom of the nitroarene can effectively enrich the nitroarene molecules. Compared with the common organic conjugated polymer at present, the inorganic hyperbranched conjugated polymer formed by Si-Si bonds effectively avoids self-quenching effect caused by aggregation induction, improves the sensing performance of the nitroarene, and greatly improves the solubility of the polymer in a common solvent by the Si-Si flexible chain.

Drawings

FIG. 1 is a scheme of the synthesis of compounds of the present invention.

FIG. 2 shows a comparison of the infrared spectra of Compound I, Compound II and Compound IV of the present invention.

FIG. 3 is a test chart of X-ray diffraction of Compound IV of the present invention.

Fig. 4 is an SEM picture of solid particles of compound IV of the present invention.

FIG. 5 is a graph of the nitrogen adsorption and desorption (A) of the compound of the present invention and its pore size distribution (B).

FIG. 6 is a graph of the UV-visible absorption (A) and fluorescence emission (B) spectra of compounds II and IV of the present invention and spin-on-film glass sheets thereof.

FIG. 7 is a plot of the fluorescence quenching of compounds II (A) and IV (B) against TNT in THF.

FIG. 8 is a plot of the quenching rate of Compounds II and IV on TNT in THF for the curves (A) and K_SV(B) Graph is shown.

FIG. 9 is a graph showing the change of fluorescence of spin-coated films of compound II (A) and compound IV (B) with time in a saturated steam of DNT.

FIG. 10 is a graph comparing the quenching rate curves of spin-on films of compounds II and IV.

Fig. 11 is a graph of the quenching effect of a portable assay made with compound IV on TNT solution.

FIG. 12 is a graph showing the reversible effect of fluorescence quenching on spin-coated films of Compound IV.

FIG. 13 is a hydrogen nuclear magnetic resonance spectrum of octa (3-mercaptopropyl) POSS (I).

FIG. 14 is a nuclear magnetic spectrum of poly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (II).

FIG. 15 shows the nuclear magnetic spectrum of three-dimensional hyperbranched conjugated polymer (3D-HPs) (IV).

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

The reagents of the experimental materials of the present invention are shown in Table 1.

TABLE 1 Main raw materials and reagents

The experimental apparatus of the present invention is shown in Table 2.

TABLE 2 Main Experimental Equipment

Interpretation of terms in the present invention:

the overnight time in the invention is 8-16 h.

In the present invention, a plurality of means two or more.

The room temperature in the present invention is 18 to 37 ℃.

The sigma conjugation in the invention means that sigma electrons of a polysilane main chain can be widely delocalized along a Si-Si main chain due to small electronegativity and an empty 3d orbit of a Si atom in polysilane, so that a sigma conjugation effect is generated.

As introduced in the background art, aiming at the defects in the prior art and solving the technical problems, the invention provides a silicon-based hyperbranched conjugated polymer which is formed by polymerizing a plurality of branching units and has the number average molecular weight of 3-6 multiplied by 10⁵g·mol^-1And each branching unit is a hyperbranched structure which takes three-dimensional octa (3-mercaptopropyl) -cage-type silsesquioxane (POSS) (also called octa-mercaptopropyl POSS) as a core and takes polysilane as a side chain, and the terminal mercapto group of the core compound is connected with poly- (dihalo-methylphenyl silane-co-dihalo-diphenylsilane) (also called copolymerization- (dihalo-methylphenyl silane-co-dihalo-diphenylsilane)).

Wherein the octa (3-mercaptopropyl) -three-dimensional cage typeSilsesquioxane (POSS) refers to T₈Eight vertex angle silicon atoms of the three-dimensional cage type silsesquioxane are connected with mercaptopropyl, and the terminal group is mercapto.

Three-dimensional cage-like silsesquioxane, also known as polyhedral oligomeric silsesquioxane (POSS), is an oligomeric siloxane and has the characteristics of cage-like structure on the nanoscale. General formula (RSiO)_1.5)_nWherein n is 6, 8, 10, 12, etc., and may be further abbreviated as T₆、T₈、T₁₀Or T₁₂And the like. In terms of the easiness of preparation and the effect of improving the permeability of the material, the polyhedral oligomeric silsesquioxane (POSS) with n of 8 is optimally selected as the core of the hyperbranched polymer.

In the present invention, a polymer formed by a polymerization reaction involving two or more monomers together, which is called copolymerization, contains two or more monomer units, and such polymers are called copolymers and can be classified into random copolymers, alternating copolymers, block copolymers and graft copolymers. Since the copolymer comprises at least two kinds of structural units, it can be divided into four kinds of copolymers according to the arrangement order of the structural units, and the nomenclature of the copolymer in the case of the structural units A and B is such that a connection number is added between the two monomers, followed by bracketing and a poly character such as poly (dichloromethylphenylsilane-dichlorodiphenylsilane). It is common in international nomenclature to incorporate alt, co, b, g and, respectively, alternating, random, block and graft copolymers between the two monomer names, such as poly (dihalomethylphenylsilane-co-dihalodiphenylsilane) or copoly (dihalomethylphenylsilane-co-dihalodiphenylsilane), i.e., random copolymers representing dihalomethylphenylsilane-dihalodiphenylsilane.

A typical hyperbranched polymer of the present invention has a structure shown in FIG. 1, and the corresponding branching units have a structure shown in FIG. 2.

Among them, we can see that poly- (dihalomethylphenylsilane-co-dihalodiphenylsilane) is represented by the structures shown as 1 and 2, and this copolymer structure is represented by a conventional method in the copolymerization technical field, where the structure of the copolymer is read as: (1) it may represent a random copolymer in which two structural units randomly appear without a certain rule, but the total number of dihalodiphenylsilane monomers in the copolymer is n, the total number of dihalomethylphenylsilane is m, for the structure shown in formula 1 or formula 2, the mercapto group is connected to dihalomethylphenylsilane or dihalodiphenylsilane, rather than only referring to the direct connection of the mercapto group to dihalodiphenylsilane, the representation of the structure is determined by the specificity of random copolymerization, but the structural meaning can be conventionally known by those skilled in the art through the above explanation; (2) it may represent an alternating copolymer, representing two monomers (dihalomethylphenylsilane and dihalodiphenylsilane) arranged strictly at intervals on the macromolecular chain, where n is equal to m, or n + -1 is equal to m, the mercapto group is attached to dihalomethylphenylsilane or dihalodiphenylsilane, and not only the mercapto group is directly attached to dihalodiphenylsilane; (3) it can represent a block copolymer, and is a special polymer prepared by connecting two polymer chain segments with different properties, namely a polymer prepared by connecting a polymer chain segment formed by n dihalo-diphenyl silane monomers and a polymer chain segment formed by m dihalo-methyl-phenyl silanes.

Wherein m is 50-60, n is 35-45, the wavy line represents a branching unit which takes POSS (polyhedral oligomeric silsesquioxane) with other vertexes functionalized by polysilane as a core and is connected through mercaptopropyl, the structure of the branching unit is shown as a formula 2, and wherein the structure of the branching unit is shown as the formula 1. The polymer is a three-dimensional hyperbranched conjugated polymer.

In one embodiment of the present invention, m is 54 and n is 39.

According to the present invention, however, it is preferred that the poly- (dihalomethylphenylsilane-co-dihalodiphenylsilane) of the present invention is a random polymer. The synthesis of poly (dihalomethylphenylsilane-co-dihalodiphenylsilane) is not particularly limited, and those skilled in the art can synthesize poly (dihalomethylphenylsilane-co-dihalodiphenylsilane) according to the conventional preparation method of copolysilanes.

The poly- (dihalomethylphenylsilane-co-dihalodiphenylsilane) is poly- (dichloromethylphenylsilane-co-dichlorodiphenylsilane) or poly- (dibromomethylphenylsilane-co-dibromodiphenylsilane).

Preferably, the poly- (dihalomethylphenylsilane-co-dihalodiphenylsilane) is a random copolymeric silane, in view of solubility of the copolymeric silane and enrichment of the copolymeric silane for nitroarenes.

Through test determination, the hyperbranched polymer has a micropore and mesopore structure, wherein the mesopore diameter is distributed between 2 nm and 55nm, and the main pore diameter is distributed between 15 nm and 20nm (preferably 17 nm). The polymer has rich pore structure, increases the permeability and contact area of the nitroaromatic, and has higher detection sensitivity.

The invention also provides a preparation method of the silicon-based hyperbranched conjugated polymer, which comprises the following steps:

The synthesis of octa (3-mercaptopropyl) POSS is not particularly limited and may be carried out by a conventional method in the art. In a preferred embodiment of the present invention, however, the process for synthesizing the octa (3-mercaptopropyl) POSS comprises the steps of: dissolving concentrated HCl, deionized water and mercaptopropyl trimethoxy silane in ethanol₂And magnetically stirring and hydrolyzing at room temperature in the environment, transferring into an oil bath for magnetic stirring, cooling the reaction, putting into a freezer at the temperature of-8 ℃ for overnight (8-16 h) to obtain white precipitate, washing with ethanol, and drying to obtain a white solid compound I. Wherein:

further, the volume ratio of the concentrated HCl, the deionized water and the mercaptopropyl trimethoxy silane is 1.0: 5.0-9.0: 3.0-5.0. A further preferred volume ratio is 1.0:5.0: 4.0.

Further, the reaction time for synthesizing the octa (3-mercaptopropyl) POSS is 3-4 days, and the further preferable reaction time is 3 days.

The synthesis of poly (dihalomethylphenylsilane-co-dihalodiphenylsilane) is not particularly limited, and those skilled in the art can synthesize poly (dihalomethylphenylsilane-co-dihalodiphenylsilane) according to the conventional preparation method of copolysilanes. In a preferred embodiment of the present invention, however, the synthesis of the copoly (dihalomethylphenylsilane-co-dihalodiphenylsilane) comprises the following steps: copolymerizing dihalo methyl phenyl silane and dihalo diphenyl silane in a sodium sand toluene dispersion system by utilizing a Wurtz reaction (Wurtz reaction), and refluxing; methanol was then added and the crude product was collected, washed sequentially with toluene, Tetrahydrofuran (THF) and water to give compound II as a white powder. Wherein:

in order to enable the copolymerization silane and the POSS to generate effective synergistic effect and enable the effective conjugation length of the copolymerization silane to be increased, through experimental verification, the molar ratio of the dihalo methyl phenyl silane to the dihalo diphenyl silane is 1.0: 0.5-1.5. A further preferred molar ratio is 1.0: 1.3.

Further, in order to enable mercapto-alkene click chemistry reaction, functional group alkenyl group, preferably vinyl group, needs to be added to the terminal of the group of the copoly (dihalomethylphenylsilane-co-dihalodiphenylsilane) to obtain vinyl copoly (dihalomethylphenylsilane-co-dihalodiphenylsilane) (compound III). The synthesis of the vinyl copolymer (dihalomethylphenylsilane-co-dihalodiphenylsilane) is not particularly limited, and those skilled in the art can perform conventional synthesis based on the structure of the compound and common general knowledge. In a preferred embodiment of the present invention, however, the method for synthesizing the vinyl copolymer (dihalomethylphenylsilane) comprises the following steps: adding vinyl magnesium halide (preferably vinyl magnesium chloride or vinyl magnesium bromide) into a solution of copoly (dihalomethylphenylsilane-co-dihalodiphenylsilane) in anhydrous THF at room temperature; heating and stirring the solution; THF was removed by distillation and the product was concentrated; dissolving the remaining reaction mixture in dichloromethane, and filtering to remove by-product salt; finally, a white powdery vinyl copolymer (dihalomethylphenylsilane-co-dihalodiphenylsilane) (i.e., compound III) was obtained.

More preferably, the addition ratio of the vinyl magnesium halide to the copolymerized (dihalo-methyl-phenyl silane-co-dihalo-diphenyl silane) is (0.1 to 1) mL: (0.1-0.15) g; the most preferred amount added is 0.1 mL: 0.13 g.

The reaction temperature for synthesizing the vinyl poly (dihalomethylphenylsilane-co-dihalodiphenylsilane) is preferably 40 to 60 ℃, and more preferably 60 ℃.

In the invention, the reaction solvent adopted in the mercapto-alkene click chemistry reaction is anhydrous toluene, and the reaction solvent is adopted, so that the reaction is more favorably carried out.

In the invention, the radical initiator adopted in the mercapto-alkene click chemistry reaction is azobisisobutyronitrile

(AIBN), with which the polymerization effect is excellent.

In the invention, the reaction for synthesizing the sigma-containing conjugated hyperbranched polymer is carried out under the condition of inert gas, and the inert gas can be argon or nitrogen.

In the present invention, the mass ratio of the octa (3-mercaptopropyl) POSS, the vinyl copoly (dihalomethylphenylsilane-co-dihalodiphenylsilane) and the Azobisisobutyronitrile (AIBN) is 1.0:0.1 to 0.6:0.10 to 0.15, and a more preferable mass ratio is 1:0.6: 0.10.

In some preferred embodiments of the present invention, the method specifically comprises the following steps:

mixing octa (3-mercaptopropyl) POSS, AIBN and vinyl poly (dihalo methyl phenyl silane-co-dihalo diphenyl silane) in an inert gas environment, and heating in an oil bath; then the oil bath was removed and the solution was exposed to air; cooling, separating out a crude product, washing with chloroform for multiple times, combining filtrate, standing for 8-16 h at room temperature, drying, and recovering a product in the filtrate to obtain a white powdery compound (IV).

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.

Example 1

The synthetic route is shown in figure 1:

(1) the preparation method of the octa (3-mercaptopropyl) POSS (I) comprises the following steps:

in N₂To the ambient, a three-necked flask was charged with ethanol (240mL), deionized water (17.5mL) and concentrated HCl (2.5mL, 37%) and stirred and heated to reflux. Mercaptopropyltrimethoxysilane (10mL) was then added and refluxing was continued for 1 day. The reaction was allowed to cool and then placed in a freezer at-8 ℃ overnight to give a white precipitate. Filtering, recovering white precipitate, and filtering the filtrate in N₂Collected in another flask. The white precipitate was then washed several times with ethanol and dried in an oven at 60 ℃ overnight (7% yield), then the filtrate from above was refluxed for a further 3 days and cooled in a freezer at 8 ℃ overnight, yielding more white precipitate. Filtration was carried out as described above and the filtrate was refluxed at 90 ℃ for a further 24 hours. The solution was allowed to cool and then placed in a freezer at-8 ℃ overnight, with a total yield of 15%. White solid (I) was obtained.

¹H-NMR:(CDCl₃,400MHz),(ppm):5.30(s,8H),2.57(s,16H),1.72(s,16H),0.78(s,16H).ATR-FTIR(cm^-1):2926,2552,1122,1025,470. FIG. 13 is a nuclear magnetic spectrum of octa (3-mercaptopropyl) POSS (I).

(2) Synthesis of copoly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (II):

to anhydrous toluene (90mL) was added sodium metal (0.08mol, 1.84g) and a sodium sand dispersion was made. Dichloromethylphenylsilane (0.04mol, 9.55g) and dichlorodiphenylsilane (0.05mol, 12.70g) were dissolved in anhydrous toluene (90mL), and the mixture was slowly added dropwise to the sodium sand dispersion solution and refluxed for 12 hours. Then a small amount of methanol was added and the crude product was collected, washed successively with toluene, THF and water. Yield 65% and product as white powder (II).

¹H-NMR:(CDCl₃,400MHz),(ppm):7.50～5.5(br,12H),0.2～-1.1(br,3H).ATR-FTIR(cm^-1) 3042,2920,1663,1431,1102,786,735,697,467. FIG. 14 is a nuclear magnetic spectrum of poly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (II) wherein the number of dichloromethylphenylsilane monomers is 54 and the number of dichlorodiphenylsilane monomers is 39.

(3) Synthesis of vinyl copolymer (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (III)

Copolymerization of (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (PDMPS) (5X 10)^-7mol, 0.13g) were transferred into a dry three-necked flask equipped with a condensing unit and magnetic stirring. Anhydrous THF (10mL) was added to the reaction vessel by syringe and the solution was heated to 60 ℃. Vinyl magnesium chloride (0.1mL of a 1M solution of vinyl magnesium chloride in THF) was added slowly via syringe. The reaction was carried out at 60 ℃ for 24 hours. THF was removed by distillation and the product was concentrated. The remaining reaction mixture was dissolved in dichloromethane (150mL) and filtered to remove the by-product salt. The product was dried under vacuum at 100 ℃ to give white powder (III).

(4) Synthesis of three-dimensional hyperbranched conjugated Polymer (3D-HPs) (IV)

In N₂Octa (3-mercaptopropyl) POSS (0.050mol, 52.80g) and AIBN (0.005mol, 0.80g) were dissolved in dry toluene (0.25mL) at ambient. Vinyl copoly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (0.006mol, 60g) was then added and the flask was placed in an oil bath at 80 ℃ for 6 hours. The oil bath was then removed and the solution was exposed to air. Precipitating at about 40 deg.C, and recovering product. The reaction flask was washed with chloroform, the combined filtrates were allowed to stand overnight at room temperature, and the flask was dried in a vacuum oven at 60 ℃ for 4 hours to give a white powder (IV).

¹H-NMR:(CDCl₃,400MHz),(ppm):7.50～5.70(br,32H),2.58(s,16H),1.73(s,16H),0.79(s,16H),0.10～-1.11(br,16H).ATR-FTIR(cm^-1) 3042,2926,1663,1431,1122,1025,786,735,465. fig. 15 showsNuclear magnetic spectrum of three-dimensional hyperbranched conjugated polymer (3D-HPs) (IV).

Example 2

(1) Synthesis of octa (3-mercaptopropyl) POSS (I):

in N₂To the ambient, a three-necked flask was charged with ethanol (240mL), deionized water (12.5mL) and concentrated HCl (2.5mL, 37%) and stirred and heated to reflux. Mercaptopropyltrimethoxysilane (7.5mL) was then added and refluxing was continued for 1 day. The reaction was allowed to cool and then placed in a freezer at-8 ℃ overnight to give a white precipitate. Filtering, recovering white precipitate, and filtering the filtrate in N₂Collected in another flask. The white precipitate was then washed several times with ethanol and dried in an oven at 60 ℃ overnight (3% yield), then the filtrate from above was refluxed for a further 4 days, followed by cooling in a freezer at 8 ℃ overnight, yielding more white precipitate. Filtration was carried out as described above and the filtrate was refluxed at 90 ℃ for a further 24 hours. The solution was allowed to cool and then placed in a freezer at-8 ℃ overnight, with a total yield of 11% to give (I) as a white solid.

to anhydrous toluene (90mL) was added sodium metal (0.08mol, 1.84g) and a sodium sand dispersion was made. Dichloromethylphenylsilane (0.04mol, 9.55g) and dichlorodiphenylsilane (0.02mol, 5.08g) were dissolved in anhydrous toluene (90mL), and the mixture was slowly added dropwise to the sodium sand dispersion solution and refluxed for 12 hours. Then a small amount of methanol was added and the crude product was collected, washed sequentially with toluene, THF and water. Yield 50% the product was a white powder (II).

(3) Synthesis of vinyl copolymer (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (III):

copolymerization of (dichloromethylphenylsilane) (PDMPS) (5X 10)^-7mol, 0.13g) were transferred into a dry three-necked flask equipped with a condensing unit and magnetic stirring. Anhydrous THF (10mL) was added to the reaction vessel by syringe and the solution was heated to 60 ℃. Vinyl magnesium chloride (0.5mL of a 1M solution of vinyl magnesium chloride in THF) was added slowly via syringe. The reaction was carried out at 60 ℃ for 24 hours. By distillationTHF was removed and the product was concentrated. The remaining reaction mixture was dissolved in dichloromethane (150mL) and filtered to remove the by-product salt. The product was dried under vacuum at 100 ℃ to give white powder (III).

(4) Synthesis of three-dimensional hyperbranched conjugated Polymer (3D-HPs) (IV):

in N₂Octa (3-mercaptopropyl) POSS (0.050mol, 52.8g) and AIBN (0.003mol, 0.48g) were dissolved in dry toluene (0.25mL) at ambient. Then vinyl copoly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (0.005mol, 50g) was added and the flask was placed in an oil bath at 60 ℃ for 6 hours. The oil bath was then removed and the solution was exposed to air. The product was recovered by precipitation at about 40 ℃. The reaction flask was washed with chloroform, the combined filtrates were allowed to stand overnight at room temperature, and the flask was dried in a vacuum oven at 60 ℃ for 6 hours to give a white powder (IV).

Example 3

(1) Synthesis of octa (3-mercaptopropyl) POSS (I):

in N₂To the ambient, a three-necked flask was charged with ethanol (240mL), deionized water (22.5mL) and concentrated HCl (2.5mL, 37%) and stirred and heated to reflux. Mercaptopropyltrimethoxysilane (12.5mL) was then added and refluxing was continued for 1 day. The reaction was allowed to cool and then placed in a freezer at-8 ℃ overnight to give a white precipitate. The white precipitate was recovered by filtration under gravity and the filtrate was taken up in N₂Collected in another flask. The white precipitate was then washed several times with ethanol and dried in an oven at 60 ℃ overnight (5% yield), then the filtrate from above was refluxed for a further 3.5 days, followed by cooling in a freezer at 8 ℃ overnight, yielding more white precipitate. Filtration was carried out as described above and the filtrate was refluxed at 90 ℃ for 24 hours. The solution was allowed to cool and then placed in a freezer at-8 ℃ overnight, with a total yield of 13%. White solid (I) was obtained.

to anhydrous toluene (90mL) was added sodium metal (0.08mol, 1.84g) and a sodium sand dispersion was made. Dichloromethylphenylsilane (0.04mol, 9.55g) and dichlorodiphenylsilane (0.06mol, 19.05g) were dissolved in anhydrous toluene (90mL), and the mixture was slowly added dropwise to the sodium sand dispersion solution and refluxed for 12 hours. Then a small amount of methanol was added and the crude product was collected, washed sequentially with toluene, THF and water. Yield 52% and product as white powder (II).

(3) Synthesis of vinyl Poly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (III):

copolymerization of (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (PDMPS) (5X 10)^-7mol, 0.13g) were transferred into a dry three-necked flask equipped with a condensing unit and magnetic stirring. Anhydrous THF (10mL) was added to the reaction vessel by syringe and the solution was heated to 60 ℃. Vinyl magnesium chloride (1.0mL of a 1M solution of vinyl magnesium chloride in THF) was added slowly via syringe. The reaction was carried out at 60 ℃ for 24 hours. THF was removed by distillation and the product was concentrated. The remaining reaction mixture was dissolved in dichloromethane (150mL) and filtered to remove the by-product salt. The product was dried under vacuum at 100 ℃ to give white powder (III).

in N₂Octa (3-mercaptopropyl) POSS (0.050mol, 52.8g) and AIBN (0.002mol, 0.32g) were dissolved in dry toluene (0.25mL) at ambient. Vinyl copoly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (0.007mol, 75g) was then added and the flask was placed in an oil bath at 70 ℃ for 6 hours. The oil bath was then removed and the solution was exposed to air. Precipitating at about 40 deg.C, and recovering product. The reaction flask was washed with chloroform, the combined filtrates were allowed to stand overnight at room temperature, and the flask was dried in a vacuum oven at 60 ℃ for 8 hours to give a white powder (IV).

Example 4 basic Properties of the Polymer in example 1

(1) Physicochemical properties of octa (3-mercaptopropyl) POSS (I), copoly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (II) and three-dimensional hyperbranched conjugated polymer (3D-HPs) (IV)

Infrared of octa (3-mercaptopropyl) POSS (I), copoly (dichloromethylphenylsilane-co-dichlorodiphenylsilane) (II) and three-dimensional hyperbranched conjugated polymer (3D-HPs) (IV)The spectrum is shown in FIG. 2. It can be seen that the infrared spectrum of the three-dimensional hyperbranched conjugated polymer (3D-HPs) (IV) is 1122and 1025cm^-1The peak increasing type is widened, and is a Si-O-Si stretching vibration absorption peak on the octa (3-mercaptopropyl) POSS (I); the infrared spectrum of the three-dimensional hyperbranched conjugated polymer (3D-HPs) (IV) is 3042cm^-1The new peak is an unsaturated C-H stretching vibration absorption peak on the copolymerization (dichloromethyl phenyl silane-co-dichlorodiphenylsilane) (II), which shows that the three-dimensional hyperbranched conjugated polymer (3D-HPs) (IV) has the characteristic peaks of the compound I and the compound II, thereby further illustrating the successful synthesis of the compound IV.

The GPC measurement result of the Compound IV showed that the number-average molecular weight was 4.107X 10⁴g·mol^-1Molecular weight distribution index 1.05. Indicating that compound IV is a high molecular weight monodisperse polymer.

The thermal stability test of the compound IV shows that the weight loss starts at 341 ℃ and is higher than the thermal decomposition temperature (271 ℃) of the compound II, so that on one hand, the introduction of a POSS structure with higher thermal stability can increase the thermal stability of the compound II; on the other hand, the compound IV has better thermal stability and good solubility in tetrahydrofuran with low boiling point, which is beneficial to film formation.

Compound IV was ground to a fine powder and subjected to X-ray diffraction. The results are shown in FIG. 3, and the diffraction pattern is analyzed, and a distinct peak pattern appears at 2 theta ≈ 20 degrees, which indicates that the compound has T₈-POSS cage structure. The experimental result, which was calculated from bragg equation (2dsin θ ═ n λ), that the interplanar distance d was 1.5nm, confirmed that compound IV was a three-dimensional molecule having a cage structure.

(2) Testing of nitrogen adsorption isotherms

The environmental scanning electron micrograph of compound IV is shown in fig. 4.

100mg of compound IV are degassed at 150 ℃ for at least 24 hours and the compound is subjected to nitrogen adsorption measurements using UHP grade nitrogen (99.999%) at 77K, the results are shown in FIG. 5. And analyzing the nitrogen adsorption isotherm, wherein the hysteresis loop belongs to type II, and the compound IV is of a micropore and mesopore structure. As can be seen from FIG. 5B, the pore size distribution is broad, with a primary pore size of 17 nm. The experimental result shows that the compound IV is a three-dimensional pore passage structure molecule with a micropore and mesopore structure.

(3) Absorption and emission Properties of Compound IV and Compound II

As shown in fig. 6, ultraviolet absorption (a) and fluorescence emission spectra (B) of compound IV and compound II. As can be seen from fig. 6(a), the maximum absorption peak of compound IV is red-shifted by approximately 14nm compared to the maximum absorption peak of compound II, because compound IV has an increased conjugated system compared to compound II, reducing the energy level difference between the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO). As can be seen from the absorption spectrum, no significant pi-pi stacking occurs between the molecules of the compound IV. As can be seen from the fluorescence spectrum of fig. 6(B), the fluorescence peak of compound IV also undergoes a significant blue shift compared to compound II, and the stokes shift of compound IV reaches 75nm, which is caused by the fact that the hyperbranched conjugated polymer has a multidimensional dendritic structure, and the rotation and vibration of the side chain consume the excited state energy, i.e., after being excited by photons, a large degree of resonance relaxation occurs, causing the fluorescence energy to decrease. The larger stokes shift is a necessary condition of the fluorescence sensing material, so the three-dimensional hyperbranched conjugated polymer (3D-HPs) has more advantages than the one-dimensional linear polymer (II).

EXAMPLE 5 detection of Trace TNT in solution Using Portable test strip for Compound IV

Test method

1) Solution preparation: 10mg of Compound IV are weighed out and dissolved in 100ml of THF to prepare 1X 10^-1g/L of the solution, and diluting the solution to prepare 1X 10^-3g/L of a THF solution of Compound IV. Filtering paper (1X 1 cm)²) Soaking in compound IV solution for 10min, naturally volatilizing solvent at room temperature, and placing in a watch glass for use. TNT was dissolved in 50mL of THF to prepare a solution of 1.0X 10^-2A mol/L TNT solution. And diluting to 7-70 μ M with equal difference.

2) Detection of trace TNT in solution with portable test paper prepared from compound IV:

the above (7, 14, 21, 28, 35, 42, 49, 56, 63 and 70. mu.M) TNT solutions were pipetted into the centers of compound IV portable test strips using glass spotting capillaries (0.3mm), and the process was carried out using a three-way UV analyzer (365nm), and the results are shown in FIG. 11 (A).

It can be seen that compared with the blank portable test paper for compound IV, the black spot quenched in the center of the test paper becomes deeper and deeper as the concentration of the TNT solution increases, and it is noted that, when trace amount of TNT solution (7 μ M) is used, the black spot quenched in the center can be seen with naked eyes, which indicates that the test paper can sensitively detect the trace amount of TNT solution. As shown in FIG. 11(B), at 70. mu.M TNT solution, the compound IV solution was completely quenched. The method not only increases the practicability of detecting the trace nitroarene solution by the fluorescent conjugated polymer, but also has the characteristics of simple method, easily obtained materials and the like.

EXAMPLE 6 preparation of fluorescent sensor

The film was coated on a glass substrate (10X 20X 1 mm) by means of a Spin Coater KW-4A Coater³) The preparation method is characterized by adopting a spin coating method.

The concentration of the compound IV and the compound II solution was 0.1g/L, and the rotation speed was 2000 rpm. And (3) dropwise adding 50uL of solution onto a glass sheet after the coating machine is at a constant speed, and naturally drying the film in the air before use, wherein the film is the sensing material of the fluorescent film sensor.

The compounds used in the following examples were prepared as in example 1.

EXAMPLE 7 optical Properties of fluorescent thin film sensor

The UV-visible absorption and fluorescence emission spectra of spin-coated films of compounds II and IV, respectively, were determined and the results are shown in FIG. 6. It can be seen that for compound II or IV, the absorption peak of the spin-coated film is broader and red-shifted than the corresponding compound in solution, indicating some stacking effect in the film. However, compared with the spin-coated film of the compound II, the spin-coated film of the compound IV with the three-dimensional POSS structure has blue shift in absorption spectrum, which shows that the POSS structure with the space effect can reduce a part of stacking effect. Compounds II and IV also show similar regularity in the fluorescence emission spectra in solution and thin film states.

EXAMPLE 8 measurement of fluorescence sensing Properties of Compounds

(1) Fluorescence quenching Properties of Compound II on TNT in THF solution

Test method

1) Solution preparation: 10mg of compound II are weighed out and dissolved in 100ml of THF to prepare 1X 10^-1g/L of the solution, and diluting the solution to prepare 1X 10^-3g/L of a THF solution of the compound II. TNT was dissolved in 50mL of THF to prepare a solution of 1.0X 10^-2A mol/L TNT solution.

2) Testing the TNT sensing performance of the compound II: TNT solutions of different concentrations were added sequentially and their fluorescence spectra were measured as shown in FIG. 7 (A). And recording the intensity of fluorescence peak, and calculating the quenching efficiency (eta) of the compound II in TNT solution with different concentrations_EP) The results are shown in FIG. 8.

(2) Fluorescence quenching of TNT by Compound IV in THF solution

Test method

1) Solution preparation: 10mg of Compound IV are weighed out and dissolved in 100ml of THF to prepare 1X 10^-1g/L solution. Taking 5 microliter of the solution, adding the solution into a 5ml volumetric flask, and fixing the volume to the scale by using THF to prepare 1X 10^-3g/L of a THF solution of Compound IV. 9mg of TNT was further dissolved in 50mL of THF to prepare 1.0X 10^-2A mol/L TNT solution.

2) Testing the TNT sensing performance of the compound IV: 3ml (concentration: 1X 10) of the THF solution of Compound IV prepared above^-3g/L)) was poured into a 100ml Erlenmeyer flask, and 5. mu.l of 1.0X 10 was added^-2The TNT solution in mol/L was mixed well, poured into a fluorescence cell, and the fluorescence spectrum (excitation wavelength 324nm) was measured with a Hitachi F-4600 type fluorescence spectrophotometer, and the fluorescence peak intensity was recorded as shown in FIG. 7 (B). To this solution was added successively 5. mu.l of 1.0X 10^-2And (3) testing the fluorescence spectrum of each TNT solution after adding the TNT solution in mol/L, and recording the corresponding fluorescence peak intensity I. The fluorescence intensity of the solution of Compound IV without addition of the quencher TNT is recorded as I₀The quenching efficiency at each time was calculated as eta_EP＝1-I/I₀. The results of the fluorescence spectra of compound IV in THF solution as a function of increasing TNT concentration are shown in FIG. 8.

It can be seen that the fluorescence intensity of the compound IV solution gradually decreased with increasing TNT concentration. When the concentration of TNT is 1.02X 10^-4At mol/L, quenching efficiency (. eta.)_EP) 80% was reached, however, when the TNT concentration continued to rise to 1.6X 10^-4mol/L, quenching efficiency slowly rises to 90%. This result revealed that compound IV has a higher response sensitivity to TNT in dilute solution. The electron transfer mechanism between donor and acceptor is the main cause of the fragmentation of compound IV by nitroarenes, and electrons in an excited state are transferred from the electron donor (compound IV) to the electron acceptor (TNT), causing the fragmentation of fluorescence.

Stern-Volmer quenching constant (K)_SV) Is an important index for evaluating the sensitivity of the sensor material, as shown in fig. 8. K comparing Compound II with Compound IV_SVIt was found that the compound IV (K) having a POSS structure introduced therein_SV＝2.83×10⁴M^-1) The sensing performance of the compound on TNT in tetrahydrofuran solution is obviously higher than that of compound II (K)_SV＝1.43×10⁴M^-1). This is because the three-dimensional POSS structure in the polymer IV effectively increases the specific surface of the material, improves the diffusion rate of TNT therein, and increases the response sensitivity of the material.

(3) Fluorescence quenching of compound II and compound IV thin film sensors in saturated DNT vapors

The sensing performance of the compound II spin-coating film sensor on gas-phase DNT is tested:

the test method comprises the following steps:

the spin-on film of compound II was carefully inserted along the diagonal of the cell (glass slide at 45 ° to the incident light). Measuring the change of the fluorescence intensity of the spin-coated film in air with time (lambda)_ex/λ_em347/425 nm). The film was removed and 100mg of DNT powder was added to the cell, capped and sealed, and allowed to stand l h at room temperature to saturate the DNT vapors in the cell. The spin-on film was then carefully inserted along the diagonal of the cell (the glass plate included 45 ℃ with the incident light) and the time-dependent change in fluorescence intensity of the spin-on film in air containing DNT (lambda_ex/λ_em347/425 nm). Test resultsAs shown in fig. 9 (a).

As shown in FIG. 10, the fluorescence intensity of the spin-coated thin film instantly decreased to 30% of that of the DNT saturated vapor (quenching efficiency 70%) upon insertion of the spin-coated thin film into the DNT saturated vapor, indicating that the fluorescence intensity of the monomolecular film sensor was responsive to DNT vapor but the quenching effect was poor.

The sensing performance of the compound IV spin-coated film on gas-phase DNT is tested:

the test method comprises the following steps: spin-on film of compound IV was carefully inserted along the diagonal of the cell (the film included 45 ° to the incident light). Measuring the change of the fluorescence intensity of the spin-coated film in air with time (lambda)_ex/λ_em330/405 nm). The film was removed and 100mg of DNT powder was added to the cell, capped and sealed, and allowed to stand l h at room temperature to saturate the DNT vapors in the cell. The spin-on film was then carefully inserted along the diagonal of the cell (the angle between the film and the incident light was 45 °), and the time-dependent change in fluorescence intensity of the spin-on film in air containing DNT (λ @)_ex/λ_em330/405 nm). The test results are shown in fig. 9 (B).

As shown in FIG. 10, the fluorescence intensity of the spin-coated thin film instantly decreased to 18% of that of the DNT saturated vapor (quenching efficiency: 82%) upon insertion of the spin-coated thin film into the DNT saturated vapor, indicating that the fluorescence intensity of the monomolecular film sensor was sensitive to DNT vapor response, rapidly reached its quenching response equilibrium, and was substantially completely quenched within 300 s. However, the conventional thin film sensor usually needs a certain time to reach the quenching response balance, and the quenching efficiency is low. And a POSS structure and a three-dimensional pore structure are introduced, so that the permeability of DNT molecules is increased, and the quencher molecules are fully contacted with the sensing unit. In particular, on polysilane, positively charged silicon atoms can form non-covalent bonds with N/O atoms of nitroarene, and have enrichment effect on nitroarene. It can be seen that the compound IV spin-on-film glass plate sensor with the POSS structure is introduced to show a remarkable advantage in response speed.

(4) Cyclability test of compound IV films

Method for testing cyclicity of polymer film under saturated DNT vapor pressure environmentThe method comprises the following steps: firstly, recording the fluorescence spectrum of a polymer film without quenching, then placing the film sensor into a cuvette reaching DNT saturated vapor pressure to detect the fluorescence spectrum and record the fluorescence spectrum; then using N as the thin film sensor₂And purging for multiple times, and recording the fluorescence spectrum of the thin film sensor again. This cycle was repeated 5 times. The change in the peak value of the fluorescence spectrum is shown in FIG. 12. It can be seen in the graph that the fluorescence intensity of the polymer film after the 1 st cycle decreased by 12.7%, while the fluorescence intensity of the polymer film after the 5 th cycle decreased by 19.6%. From the first to the fifth cycle, the quenching efficiency dropped from 81.99% to 77.5%. The polymer film sensor has better cyclicity from the test result.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A silicon-based hyperbranched conjugated polymer is polymerized by a plurality of branching units and is characterized in that: the number average molecular weight of the polymer is 3 to 6 x 10⁴g·mol^-1The molecular weight distribution index of the modified poly (methyl phenyl silane) -co-diphenylsilane copolymer is 1.05-1.50, each branching unit takes eight (3-mercaptopropyl) -three-dimensional cage-like silsesquioxane as a core compound, and the tail end of the core compound is connected with poly (methyl phenyl silane-co-diphenylsilane) through a mercapto-alkene click chemical reaction;

the poly (methylphenylsilane-co-diphenylsilane) is a random copolysilane;

the molar ratio of the raw materials dihalo-methyl-phenyl silane and dihalo-diphenyl silane for forming the poly (methyl phenyl silane-co-diphenyl silane) is 1.0: 0.5-1.5.

2. The method for preparing the silicon-based hyperbranched conjugated polymer as set forth in claim 1, which comprises the steps of:

synthesizing the silicon-based hyperbranched conjugated polymer by reacting octa (3-mercaptopropyl) -three-dimensional cage-type silsesquioxane with poly (methylphenyl silane-co-diphenylsilane) through a mercapto-alkene click chemistry reaction.

3. The method of claim 2, wherein:

the synthesis of poly (methylphenylsilane-co-diphenylsilane) includes the following steps: copolymerizing dihalo methyl phenyl silane and dihalo diphenyl silane in a sodium sand toluene dispersion system by utilizing a Wurtz reaction, and refluxing; methanol was then added and the crude product was collected, washed sequentially with toluene, tetrahydrofuran and water to give poly (methylphenylsilane-co-diphenylsilane).

4. The method of claim 1, wherein: the molar ratio of the starting dihalomethylphenylsilane to dihalodiphenylsilane to form poly (methylphenylsilane-co-diphenylsilane) was 1.0: 1.3.

5. The method of claim 2, wherein: the reaction solvent adopted in the sulfydryl-alkene click chemistry reaction is anhydrous toluene.

6. The method of claim 2, wherein: the free radical initiator adopted in the mercapto-alkene click chemistry reaction is azobisisobutyronitrile.

7. The method of claim 2, wherein: the reaction time for synthesizing the silicon-based hyperbranched conjugated polymer is 4-8 hours; the reaction temperature is 60-80 ℃.

8. The method of claim 7, wherein: the reaction time for synthesizing the silicon-based hyperbranched conjugated polymer is 4 hours; the reaction temperature was 60 ℃.

9. The method of claim 2, wherein: the reaction for synthesizing the silicon-based hyperbranched conjugated polymer is carried out under the condition of inert gas, and the inert gas is argon or nitrogen.

10. The method of claim 2, wherein: when the sulfydryl-alkene click chemical reaction is carried out, vinyl poly (methyl phenyl silane-co-diphenylsilane) is adopted; the mass ratio of the octa (3-mercaptopropyl) -three-dimensional cage-type silsesquioxane to the vinyl poly (methylphenylsilane-co-diphenylsilane) to the azobisisobutyronitrile is 1.0: 0.1-0.6: 0.10-0.15;

the synthesis method of vinyl poly (methyl phenyl silane-co-diphenyl silane) includes the following steps: adding vinyl magnesium halide into the poly (methyl phenyl silane-co-diphenyl silane) anhydrous THF solution at room temperature; heating and stirring the solution; THF was removed by distillation and the product was concentrated; dissolving the remaining reaction mixture in dichloromethane, and filtering to remove by-product salt; finally, vinyl poly (methyl phenyl silane-co-diphenyl silane) is obtained;

the reaction temperature for synthesizing the vinyl poly (methyl phenyl silane-co-diphenyl silane) is 40-60 ℃; the addition ratio of the vinyl magnesium halide to the poly (methyl phenyl silane-co-diphenyl silane) is 0.1-1 mL: 0.1 to 0.15 g.

11. The method of claim 10, wherein: the mass ratio of the octa (3-mercaptopropyl) -three-dimensional cage-type silsesquioxane to the vinyl poly (methylphenylsilane-co-diphenylsilane) to the azobisisobutyronitrile is 1:0.6: 0.10.

12. The method of claim 10, wherein: the reaction temperature for synthesizing the vinyl poly (methyl phenyl silane-co-diphenyl silane) is 60 ℃; the addition ratio of the vinyl magnesium halide to the poly (methylphenylsilane-co-diphenylsilane) was 0.1 mL: 0.13 g.

13. The method of claim 2, wherein: the specific reaction process comprises the following steps: mixing octa (3-mercaptopropyl) -three-dimensional cage-type silsesquioxane, azobisisobutyronitrile and vinyl poly (methyl phenyl silane-co-diphenylsilane) in an inert gas environment, and heating in an oil bath; then the oil bath was removed and the solution was exposed to air; and precipitating and recovering the product, washing with chloroform, combining the filtrates, standing for 8-16 h at room temperature, and drying to obtain the silicon-based hyperbranched conjugated polymer.