阅读说明：本技术 一种高分子单链纳米颗粒串状组装结构及其制备方法与应用 (High-molecular single-chain nanoparticle string-shaped assembly structure and preparation method and application thereof ) 是由 史聪灵 井静云 刘国林 侯正波 钱小东 于 2021-02-19 设计创作，主要内容包括：本发明涉及高分子材料技术领域,具体公开了一种高分子单链纳米颗粒串状组装结构及其制备方法与应用。纳米颗粒串状组装结构由通过活性阳离子聚合方法制备得到的尺寸相当的单链纳米颗粒经表面改性后组装而成；具体由同种改性后的单链纳米颗粒接枝于同一聚合物链构成；或由至少两种改性后的单链纳米颗粒通过颗粒表面官能团间的点击反应顺序连接构成。本发明通过控制聚合或聚合物功能化等技术在颗粒表面引入特定官能团,利用官能团间的点击反应,实现颗粒在高分子链上的接枝和颗粒间相互连接。所获得的组装结构中纳米颗粒表面的一种或多种官能团具有特异识别性,可实现材料对特定物质的筛选和识别过程,构建潜在纳米识别“基因库”。(The invention relates to the technical field of high polymer materials, and particularly discloses a high polymer single-chain nanoparticle string-shaped assembly structure and a preparation method and application thereof. The nano-particle string-shaped assembly structure is formed by assembling single-chain nano-particles with the same size, which are prepared by an active cationic polymerization method, after surface modification; the modified single-chain nano-particles are grafted on the same polymer chain; or at least two kinds of modified single-chain nano-particles are connected in sequence through click reaction among functional groups on the surfaces of the particles. The invention introduces specific functional groups on the particle surface by controlling polymerization or polymer functionalization and other technologies, and realizes grafting of particles on a macromolecular chain and mutual connection among particles by utilizing click reaction among the functional groups. One or more functional groups on the surface of the nano particles in the obtained assembly structure have specific identification, so that the screening and identification process of the material on specific substances can be realized, and a potential nano identification 'gene library' is constructed.)

1. A nanoparticle string-shaped assembly structure is characterized in that the assembly structure is formed by assembling single-chain nanoparticles prepared by an active cationic polymerization method after surface modification, wherein the single-chain nanoparticles have the same size;

the nanoparticle string-shaped assembly structure comprises a pendant structure formed by grafting modified single-chain nanoparticles on the same polymer chain; or a pearl string structure formed by connecting at least two modified single-chain nano particles in sequence through click reaction among functional groups on the surfaces of the particles.

2. The string-shaped nanoparticle assembly structure according to claim 1, wherein the surface functional group of the modified single-chain nanoparticle is an amino group, a carboxyl group, an aldehyde group, a thiol group, benzyl chloride, a double bond, or a methyl group; the reaction involved in the assembly of the single-chain nano-particles is Schiff base reaction, amidation reaction, rapid termination reaction or oxidative condensation reaction.

3. The string-like assembly structure of nanoparticles according to claim 1 or 2, wherein the size of the single-chain nanoparticles is 2-10 nm.

4. The string-shaped nanoparticle assembly structure according to claim 3, wherein the single-chain nanoparticles are one or more of polyvinyl benzenes, polyvinyl ethers, polyalkylene oxides, polyvinyl conjugates, or polyvinyl coupling agent-based polymer single-chain nanoparticles;

preferably, polystyrene, poly (p-methylstyrene), poly (. alpha. -methylstyrene), poly (p-methoxystyrene), poly (p-chlorostyrene), poly (4-tert-butylstyrene), poly (4-chloromethylstyrene), poly (3-aldehydic styrene) single-chain nanoparticles; or, polyvinyl ether, polymethyl vinyl ether, polyisobutyl vinyl ether, poly-tert-butyl vinyl ether, poly-octadecyl vinyl ether or poly-dodecyl vinyl ether single-chain nanoparticles; or, polypropylene oxide, poly (1, 2-butylene oxide), polybromopropylene oxide, polychloropropylene oxide, poly (1, 2-heptaneoxide), poly (oxypropyl phenyl ether), poly (3-glycidoxypropyl) methyldiethoxysilane, or polyglycidyl methacrylate single-chain nanoparticles; or, polyisoprene, polybutadiene single-chain nanoparticles; or, one or more of polystyrene ethyl trimethoxy silane, polymethyl styrene silane, polyvinyl methyl dimethoxy silane, polyvinyl trimethoxy silane and polyvinyl triethoxy silane single-chain nano-particles.

5. A method for preparing the nanoparticle string assembly structure of any one of claims 1 to 4, comprising the step of grafting the same modified single-chain nanoparticle onto the same polymer chain by Schiff base reaction, amidation reaction, rapid termination reaction or oxidative condensation reaction, wherein the concentration of the polymer chain is less than or equal to 0.1% by mass percentage;

or, the method comprises the step of connecting at least two modified single-chain nano-particles sequentially through click reaction between functional groups on the surfaces of the particles.

6. The method as claimed in claim 5, wherein the specific method for preparing pendant structures formed by grafting modified single-chain nanoparticles of the same species to the same polymer chain comprises:

(1) under the action of an initiator, cationic polymerization is carried out in dichloromethane or free radical polymerization is carried out in toluene to prepare poly (4-chloromethyl styrene), and then the prepared poly (4-chloromethyl styrene) is dissolved in dimethyl sulfoxide for Kornblum oxidation reaction to prepare an aldehyde group polymer chain;

(2) under the action of an initiator, carrying out cationic polymerization of styrene ethyl trimethoxy silane monomer and a divinyl benzene cross-linking agent in dichloromethane, and after the polymerization is finished, adding a small amount of ethanol to carry out sol-gel reaction to prepare silane high-molecular single-chain nano particles;

(3) dissolving the silane high-molecular single-chain nano-particles prepared in the step (2) in toluene, and then adding 3-aminopropyltriethoxysilane and a very small amount of acid catalyst to prepare amino modified nano-particles;

(4) and (3) dissolving the amino modified nanoparticles prepared in the step (3) in dichloromethane, adding the aldehyde-based polymer chain prepared in the step (1) and a very small amount of acid catalyst to perform Schiff base reaction, and then constructing a pendant structure in which the amino modified single-chain nanoparticles are grafted on the aldehyde-based polymer chain through reduction.

7. The method as claimed in claim 5, wherein the specific method for preparing the pearl string structure formed by the crossed arrangement of the two modified single-chain nano-particles A, B comprises the following steps:

(1) under the action of an initiator, carrying out cationic polymerization on a 4-chloromethyl styrene monomer and a divinylbenzene crosslinking agent in dichloromethane to prepare high-molecular single-chain nano-particles;

(2) dissolving the polymer single-chain nano-particles prepared in the step (1) in dimethyl sulfoxide to carry out Kornblum oxidation reaction, and preparing aldehyde single-chain nano-particles;

(3) dissolving the aldehyde single-chain nanoparticles prepared in the step (2) in dichloromethane, adding mercaptoethylamine and a very small amount of acid catalyst to perform Schiff base reaction in a nitrogen atmosphere, and then preparing sulfhydryl modified single-chain nanoparticles through reduction;

(4) respectively reacting the sulfhydryl modified single-chain nano-particles prepared in the step (3) with butenoic acid and allylamine to prepare carboxyl modified single-chain nano-particles A and amino modified single-chain nano-particles B;

(5) dissolving carboxyl modified single-chain nano-particles A in dichloromethane, activating carboxyl by using dicyclohexylcarbodiimide and N-hydroxysuccinimide catalysts, adding equivalent amino modified single-chain nano-particles B, and constructing a pearl string structure with the carboxyl modified single-chain nano-particles A and the amino modified single-chain nano-particles B arranged in a crossed manner through amidation reaction.

8. The method as claimed in claim 5, wherein the specific method for preparing the pearl string structure composed of five modified single-chain nanoparticles comprises:

(1) under the action of an initiator, carrying out cationic polymerization on a 4-chloromethyl styrene monomer and a divinylbenzene crosslinking agent in dichloromethane to prepare active single-chain nanoparticles a;

(2) preparing carboxyl modified single-chain nano-particles b by the same method as the carboxyl modified single-chain nano-particles A in the method of claim 7; adding the carboxyl modified single-chain nano-particles b into the reaction system in the step (1), and preparing a first connecting structure of the active single-chain nano-particles a and the carboxyl modified single-chain nano-particles b by utilizing a termination reaction between carboxyl and a carbonium ion active species;

(3) preparing amino modified single-chain nano-particles c by the same method as the amino modified single-chain nano-particles B in the method of claim 7; dissolving the first connecting structure prepared in the step (2) in dichloromethane, performing carboxyl activation under the action of dicyclohexylcarbodiimide and N-hydroxysuccinimide catalysts, then adding amino modified single-chain nanoparticles c for amidation reaction, and constructing a second connecting structure in which active single-chain nanoparticles a, carboxyl modified single-chain nanoparticles b and amino modified single-chain nanoparticles c are connected end to end;

(4) preparing aldehyde modified single-chain nano-particles d by the same method as the method for preparing aldehyde modified single-chain nano-particles in the method of claim 7; dissolving the second connecting structure prepared in the step (3) in dichloromethane, performing Schiff base reaction with aldehyde modified single-chain nanoparticles d under the action of an acid catalyst, and then constructing a third connecting structure in which active single-chain nanoparticles a, carboxyl modified single-chain nanoparticles b, amino modified single-chain nanoparticles c and aldehyde modified single-chain nanoparticles d are connected end to end through reduction;

(5) under the action of an initiator, carrying out cationic polymerization on a methylstyrene monomer and a divinylbenzene crosslinking agent in dichloromethane to prepare a poly (p-methylstyrene) single-chain nanoparticle e;

(6) and (3) dissolving the third connecting structure prepared in the step (4) in N, N-dimethylformamide, adding the poly-p-methylstyrene single-chain nanoparticles e prepared in the step (5), and performing dehydration condensation reaction under an alkaline condition to construct a pearl string structure in which the active single-chain nanoparticles a, the carboxyl modified single-chain nanoparticles b, the amino modified single-chain nanoparticles c, the aldehyde modified single-chain nanoparticles d and the poly-p-methylstyrene single-chain nanoparticles e are connected end to end.

9. Use of the nanoparticle string assembly of any one of claims 1 to 4 or the nanoparticle string assembly prepared by the method of any one of claims 5 to 8 for substance screening or nano-identification.

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a high polymer single-chain nanoparticle string-shaped assembly structure and a preparation method and application thereof.

Background

The polymer single-chain nano-particle has the characteristics that a local partition exists, an active substance such as a drug or a catalyst can be temporarily or permanently limited in the local partition, and the size and the hydrodynamic volume are reduced, so that the polymer nano-particle is regarded as the smallest. By changing the molecular weight and chemical composition of a linear polymer chain (precursor), the controllability on the particle size and chemical properties can be realized, and the polymer has application potential in aspects of nanomedicine, catalysis, construction units, solid emulsifiers, sensing and the like, thereby attracting wide attention.

The most mature method for preparing single-chain nanoparticles at present is the intramolecular cross-linking method, i.e. the preparation of single-chain nanoparticles by intramolecular cross-linking of specific blocks of block copolymers. However, in order to avoid intermolecular crosslinking, the reaction concentration is generally controlled to be extremely low (< 2%), which results in a large waste of solvent, and thus the synthesis methodology is strongly discussed. In the prior art, a rapid termination method for living cationic polymerization of high-solid-content high-molecular single-chain nanoparticles is also provided, so that batch preparation of the single-chain nanoparticles can be realized. On the basis, how to derive rich assembled superstructures by using single-chain nanoparticles and endow the superstructures with multiple functionalities still has certain challenges and needs to be deeply explored.

Disclosure of Invention

Based on the difficult problem of constructing the functionalized assembly structure taking single-chain nano particles as elements at present, the invention aims to provide a high-molecular single-chain nano particle string-shaped assembly structure and a preparation method and application thereof.

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

a nanoparticle string-shaped assembly structure is formed by assembling single-chain nanoparticles prepared by an active cation polymerization method after surface modification, wherein the single-chain nanoparticles have the same size;

the nanoparticle string-shaped assembly structure comprises a pendant structure formed by grafting modified single-chain nanoparticles on the same polymer chain; or a pearl string structure formed by connecting at least two modified single-chain nano particles in sequence through click reaction among functional groups on the surfaces of the particles.

The invention provides a polymer single-chain nanoparticle string-shaped assembly structure with a nanometer recognition function, which is formed by sequentially connecting homogeneous or heterogeneous polymer single-chain nanoparticles with the same size, and comprises a pendant structure constructed by single nanoparticles, a pearl string structure constructed by two kinds of A, B nanoparticles in a crossed manner and a pearl string structure constructed by multiple kinds of heterogeneous nanoparticles.

The three single-stranded assembly structures are schematically shown in FIG. 9. In the figure, the position of the upper end of the main shaft,represent single-chain nano-particles, which are further assembled into three single-chain nano-particle string-shaped assembly structures after being sequentially connected.

The first pendant structure is shown as the uppermost string structure in fig. 9, the second two kinds of A, B-nanoparticle cross-constructed pearl string structures are shown as the middle string structure in fig. 9, and the third kind of heterogeneous-nanoparticle constructed pearl string structures are shown as the lowermost string structure in fig. 9. In the figure, the particles of different shades represent different kinds of nanoparticles.

In the invention, the surface functional group of the modified single-chain nano-particle is amino, carboxyl, aldehyde group, sulfydryl, benzyl chloride, double bond or methyl; the reaction involved in the assembly of the single-chain nano-particles is Schiff base reaction, amidation reaction, rapid termination reaction or oxidative condensation reaction.

In the invention, the size of the single-chain nano-particles is 2-10 nm.

In the invention, the single-chain nano-particles are one or more of polyvinyl benzene, polyvinyl ether, polyalkylene oxide, conjugate polyvinyl or polyvinyl coupling agent polymer single-chain nano-particles;

preferably, polystyrene, poly (p-methylstyrene), poly (. alpha. -methylstyrene), poly (p-methoxystyrene), poly (p-chlorostyrene), poly (4-tert-butylstyrene), poly (4-chloromethylstyrene), poly (3-aldehydic styrene) single-chain nanoparticles; or, polyvinyl ether, polymethyl vinyl ether, polyisobutyl vinyl ether, poly-tert-butyl vinyl ether, poly-octadecyl vinyl ether or poly-dodecyl vinyl ether single-chain nanoparticles; or, polypropylene oxide, poly (1, 2-butylene oxide), polybromopropylene oxide, polychloropropylene oxide, poly (1, 2-heptaneoxide), poly (oxypropyl phenyl ether), poly (3-glycidoxypropyl) methyldiethoxysilane, or polyglycidyl methacrylate single-chain nanoparticles; or, polyisoprene, polybutadiene single-chain nanoparticles; or, one or more of polystyrene ethyl trimethoxy silane, polymethyl styrene silane, polyvinyl methyl dimethoxy silane, polyvinyl trimethoxy silane and polyvinyl triethoxy silane single-chain nano-particles.

More preferably, the single-chain nanoparticle is a polystyrene ethyltrimethoxysilane single-chain nanoparticle or a poly (4-chloromethylstyrene) single-chain nanoparticle. The polystyrene ethyl trimethoxy silane single-chain nano-particles have more advantages in the aspect of introducing various functional groups by surface modification. Poly (4-chloromethylstyrene) single-chain nanoparticles have advantages in polymerization activity and derivation of other functional groups from the benzyl chloride functional group contained in the nanoparticles.

The polymer chain may be poly (4-chloromethylstyrene), poly (tert-butyl acrylate), poly (p-methylstyrene), poly (3-vinylbenzaldehyde).

Preferably, poly (4-chloromethylstyrene) polymer chains, which have the advantage of high polymerization activity and of facilitating the derivation of other functional groups from the benzyl chloride functional groups contained in themselves.

In the invention, the ratio of the hydrodynamic diameter of the polymer chain to the size (average particle diameter) of the single-chain nano-particles is (4-10):1, so that more single-chain nano-particles are grafted on a single polymer chain, and the polymer chain has more advantages in enhancing the nano-recognition function.

In the invention, when the surface modification of the single-chain nano-particles is carried out by adopting a silane ligand exchange method, the silane is amino silane or carboxyl silane;

preferably, it is one or more selected from 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 4-aminobutyldimethylmethoxysilane, 4-aminobutyltriethoxysilane, 3- [ (2-aminoethylamino) propyl ] dimethoxysilane, 3- (2-aminoethylamino) propyltriethoxysilane, (3-aminopropyl) dimethylethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 4- [ (trimethylsilyl) ethynyl ] benzoic acid, and 3- [ diethoxy (methyl) silyl ] propyl methacrylate.

More preferably, the silane used is 3-aminopropyltriethoxysilane, which has the advantage of being readily available and inexpensive.

Preferably, the mass ratio of silane to single-chain nanoparticles is (5-10):1 when the silane ligands are exchanged.

The invention also provides a method for preparing the nanoparticle string-shaped assembly structure, which comprises the step of grafting the same modified single-chain nanoparticles to the same polymer chain through Schiff base reaction, amidation reaction, rapid termination reaction or oxidative condensation reaction, wherein the concentration of the polymer chain is less than or equal to 0.1 percent in mass percentage during grafting;

or, the method comprises the step of connecting at least two modified single-chain nano-particles sequentially through click reaction between functional groups on the surfaces of the particles.

The preparation method of the invention relates to the control polymerization or surface modification functionalization of polymer single-chain nano-particle assembly elements and the click reaction among particle surface functional groups.

The invention starts from single-chain nano particles prepared by active cationic polymerization, carries out proper surface modification on the particles, introduces specific functional groups, utilizes click reaction among the functional groups to realize grafting (pendant structure) of the single-chain nano particles on a polymer chain and mutual connection (pearl string structure) among the particles, and constructs rich assembly structures.

The concentration of polymer chains in grafting is particularly selected, and particularly, in the research, when the mass fraction of the polymer is less than or equal to 0.1%, a pendant structure can be well prepared in the system, and if the concentration is too high, a cross-linking state of mutual winding among the polymer chains can occur; if the concentration is too low, the reaction rate is reduced and the solvent is wasted.

The preparation of the string-shaped assembly structure in the invention is realized by the click reaction between the functional groups on the surface of the nano-particles, so that the method is one of the important research points for introducing any required functional group on the surface of a specific nano-particle. Based on this, the invention proposes two methods for preparing functional single-chain nanoparticles: polymerizing functional monomers such as aldehyde group-containing styrene, benzyl chlorostyrene and the like; ② polymerizing styrene silane monomer, introducing various functional groups, such as amino, carboxyl, sulfydryl and the like, through silane ligand exchange. Meanwhile, the invention focuses on the chemical connection process among particles, and relates to the exploration of the configuration of proper functional groups on the particle surface, the addition of different types of nano particles, the setting optimization of reaction conditions and the like.

As one preferable example, taking a poly (4-chloromethylstyrene) polymer chain as a skeleton and a particle surface with an amino functional group as an example, the preparation method of the pendant structure constructed by a single nanoparticle specifically comprises:

(1) under the action of an initiator, cationic polymerization is carried out in dichloromethane or free radical polymerization is carried out in toluene to prepare poly (4-chloromethyl styrene), and then the prepared poly (4-chloromethyl styrene) is dissolved in dimethyl sulfoxide for Kornblum oxidation reaction to prepare an aldehyde group polymer chain;

(2) under the action of an initiator, carrying out cationic polymerization of styrene ethyl trimethoxy silane monomer and a divinyl benzene crosslinking agent in dichloromethane, and after the polymerization is finished, adding a small amount of ethanol to carry out sol-gel reaction to prepare silane high-molecular single-chain nanoparticles (polystyrene ethyl trimethoxy silane single-chain nanoparticles); wherein the volume ratio of the crosslinking agent (divinylbenzene) to the monomer (styrene ethyltrimethoxysilane) is (0.05-0.3): 1.

(3) dissolving the silane high-molecular single-chain nano-particles prepared in the step (2) in toluene, and then adding 3-aminopropyltriethoxysilane and a very small amount of acid catalyst to prepare amino modified nano-particles;

preferably, the mass ratio of the 3-aminopropyltriethoxysilane to the silane high-molecular single-chain nano-particles is (5-10): 1; the acidic acidifying agent can be one or any combination of acetic acid, dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, trifluoroacetic acid and the like, and the adding amount is 0.01-0.05 percent, preferably 0.01 percent based on the volume of the reaction solvent.

(4) And (3) dissolving the amino modified nanoparticles prepared in the step (3) in dichloromethane, adding the aldehyde-based polymer chain prepared in the step (1) and a very small amount of acid catalyst to perform Schiff base reaction, and then constructing a pendant structure in which the amino modified single-chain nanoparticles are grafted on the aldehyde-based polymer chain through reduction.

Preferably, the reduction is carried out with sodium borohydride in a molar ratio (1-2: 1), preferably 1.5:1, to the 3-aminopropyltriethoxysilane added in step (3). Meanwhile, the concentration of the polymer chain is less than or equal to 0.1 percent in percentage by mass.

As one of the preferable examples, the method for preparing the pearl string structure constructed by the cross arrangement of two single-chain nano-particles of amino and carboxyl A, B specifically comprises the following steps:

(1) under the action of an initiator, carrying out cationic polymerization of a 4-chloromethyl styrene monomer and a divinylbenzene crosslinking agent in dichloromethane to prepare poly (4-chloromethyl styrene) single-chain nanoparticles (high-molecular single-chain nanoparticles);

preferably, the volume ratio of the crosslinking agent (divinylbenzene) to the 4-chloromethylstyrene monomer is (0.05 to 0.3): 1.

(2) dissolving the polymer single-chain nano-particles prepared in the step (1) in dimethyl sulfoxide to carry out Kornblum oxidation reaction, and preparing aldehyde single-chain nano-particles;

(3) dissolving the aldehyde single-chain nanoparticles prepared in the step (2) in dichloromethane, adding mercaptoethylamine and a very small amount of acid catalyst to perform Schiff base reaction in a nitrogen atmosphere, and then preparing sulfhydryl modified single-chain nanoparticles through reduction;

(4) respectively reacting the sulfhydryl modified single-chain nano-particles prepared in the step (3) with butenoic acid and allylamine to prepare carboxyl modified single-chain nano-particles A and amino modified single-chain nano-particles B;

preferably, the molar ratio of the addition of the butenoic acid or allylamine to the mercaptoethylamine in the step (3) is 1: 1.

(5) Dissolving carboxyl modified single-chain nano-particles A in dichloromethane, activating carboxyl by dicyclohexylcarbodiimide DCC and N-hydroxysuccinimide NHS catalysts, adding equivalent amino modified single-chain nano-particles B, and constructing a pearl string structure with the carboxyl modified single-chain nano-particles A and the amino modified single-chain nano-particles B arranged in a crossed manner through amidation reaction.

Preferably, the molar ratio of dicyclohexylcarbodiimide DCC, N-hydroxysuccinimide NHS to the carboxyl-modified single-chain nanoparticles A is (1.1-1.5):1: 0.2.

As one of the preferable examples, taking a pearl string assembly structure constructed by connecting 5 kinds of nanoparticles end to end as an example, the specific preparation method comprises the following steps:

(1) under the action of an initiator, carrying out cationic polymerization on a 4-chloromethyl styrene monomer and a divinylbenzene crosslinking agent in dichloromethane to prepare active single-chain nanoparticles a;

(2) preparing carboxyl modified single-chain nano particles b, wherein the specific preparation method is the same as that of the carboxyl modified single-chain nano particles A in the method; adding the carboxyl modified single-chain nano-particles b into the reaction system in the step (1), and preparing a first connecting structure of the active single-chain nano-particles a and the carboxyl modified single-chain nano-particles b by utilizing a termination reaction between carboxyl and a carbonium ion active species;

(3) preparing amino modified single-chain nano particles c, wherein the specific preparation method is the same as that of the amino modified single-chain nano particles B in the method; dissolving the first connecting structure prepared in the step (2) in dichloromethane, performing carboxyl activation under the action of dicyclohexylcarbodiimide and N-hydroxysuccinimide catalysts, then adding amino modified single-chain nanoparticles c for amidation reaction, and constructing a second connecting structure in which active single-chain nanoparticles a, carboxyl modified single-chain nanoparticles b and amino modified single-chain nanoparticles c are connected end to end;

(4) preparing aldehyde modified single-chain nano-particles d, wherein the specific preparation method is the same as that of the aldehyde modified single-chain nano-particles in the method; dissolving the second connecting structure prepared in the step (3) in dichloromethane, performing Schiff base reaction with aldehyde modified single-chain nanoparticles d under the action of an acid catalyst, and then constructing a third connecting structure in which active single-chain nanoparticles a, carboxyl modified single-chain nanoparticles b, amino modified single-chain nanoparticles c and aldehyde modified single-chain nanoparticles d are connected end to end through reduction;

(5) under the action of an initiator, carrying out cationic polymerization on a methylstyrene monomer and a divinylbenzene crosslinking agent in dichloromethane to prepare a poly (p-methylstyrene) single-chain nanoparticle e;

(6) and (3) dissolving the third connecting structure prepared in the step (4) in N, N-dimethylformamide, adding the poly-p-methylstyrene single-chain nanoparticles e prepared in the step (5), and performing dehydration condensation reaction under an alkaline condition to construct a pearl string structure in which the active single-chain nanoparticles a, the carboxyl modified single-chain nanoparticles b, the amino modified single-chain nanoparticles c, the aldehyde modified single-chain nanoparticles d and the poly-p-methylstyrene single-chain nanoparticles e are connected end to end.

The "small amount" and "extremely small amount" in the present invention are based on the guarantee of the smooth proceeding of the corresponding reaction, and the skilled in the art can select and control the amount according to the general knowledge in the field.

In the invention, the Kornblum oxidation reaction condition is that dimethyl sulfoxide is used as a solvent, sodium bicarbonate and potassium iodide are used as initiators, and the reaction is carried out for 8 to 12 hours at the temperature of between 90 and 110 ℃ under the protection of nitrogen flow; the mass ratio of potassium iodide to sodium bicarbonate added was 2: 1.

The reaction conditions in the preparation process of the high-molecular single-chain nano-particles are that anhydrous dichloromethane is used as a solvent, boron trifluoride-diethyl ether complex is used as an initiator, and the reaction is carried out for 15min-2h at-10-25 ℃; the volume ratio of the cross-linking agent to the monomer is (0.05-0.3): 1.

the Schiff base reaction condition is that the Schiff base reacts for 4 to 8 hours at the temperature of between 20 and 50 ℃ under the weak acid condition, then the Schiff base reacts for 4 to 12 hours after being cooled to the temperature of between 10 ℃ below zero and 0 ℃ and added with sodium borohydride.

The click reaction condition of the sulfydryl, the amino and the carboxyl is that azodiisobutyronitrile AIBN is used as an initiator and reacts for 8 to 12 hours at the temperature of between 50 and 80 ℃ under the protection of nitrogen flow.

The amidation reaction condition is that dicyclohexylcarbodiimide DCC and N-hydroxysuccinimide NHS are firstly mixed with carboxyl substances, and the carboxyl is activated for 15min at normal temperature. Then mixing with amino substances, reacting for 8-12h at normal temperature, and coupling.

The aldehyde group and methyl group condensation dehydration reaction condition is that alkali is used as catalytic medium, which can be selected from sodium hydroxide, potassium hydroxide, ammonia water, sodium bicarbonate, piperidine and the like, and dehydration reaction is carried out for 8-24h at 70-90 ℃.

The invention also provides an application of the nanoparticle string-shaped assembly structure or the nanoparticle string-shaped assembly structure prepared by the method in material screening or nano identification.

The invention has the beneficial effects that:

the invention provides a universal method for constructing three different nanoparticle superstructures by taking functional single-chain nanoparticles as elements, and a specific string-shaped assembly structure is prepared by sequentially connecting homogeneous or heterogeneous high-molecular single-chain nanoparticles with equivalent sizes. The method comprises the steps of preparing high-molecular single-chain nano particles by utilizing active cationic polymerization high-solid content, introducing specific functional groups on the surfaces of the particles by controlling polymerization or polymer functionalization and other technologies, realizing grafting of the particles on a high-molecular chain and mutual connection among the particles through click reaction among the functional groups, and constructing a string-shaped superstructure in a pendant structure and a pearl string structure.

The identification functional group types on the surface of the assembly body of the pendant structure include, but are not limited to, amino, carboxyl, aldehyde, sulfhydryl, benzyl chloride, double bonds and methyl; can also be prepared at the same timeContaining amino and carboxyl groups (-NH)₂and-COOH), aldehyde groups and mercapto groups (-CHO and-SH), double bonds and carboxyl groups (-C ═ C and-COOH), double bonds and amino groups (-C ═ C and-NH₂) The two A, B functional groups are arranged in a crossed way to form a pearl string structure; and a pearl string structure which is constructed by connecting n (n is more than or equal to 3) different functional groups in sequence, such as benzyl chloride, carboxyl, amino, aldehyde group, methyl (-CH)₂Cl、-COOH、-NH₂-CHO and-CH₃) And the like, and endows the string structure with stronger substance recognition capability. The superstructure of the single-chain nano-particles with rich morphology can be further derived by regulating the chemical composition of the nano-particles and the types of functional groups on the surface.

One, two or more specific functional groups on the surfaces of the nanoparticles in the three superstructures can realize the processes of specific identification, screening and combination of various substances, explore the potential application of the material as a nano identification 'gene library', and provide a new path and thought for efficient and rapid identification of specific substances (such as proteins and enzymes).

Drawings

FIG. 1 is a TEM image of 10nm single-chain nanoparticle prepared according to the present invention; a microscope JEM-1011, an accelerating voltage of 100kV and a magnification of 100000 x;

FIG. 2 is a TEM image of 2nm single-chain nanoparticle prepared according to the present invention; a microscope JEM-1011, an accelerating voltage of 100kV and a magnification of 80000 x;

FIG. 3 is a schematic diagram of a process for constructing a pendant structure by using poly (benzyl-chlorostyrene) as a skeleton and amino functional groups on the surface of particles in example 1 of the present invention;

FIG. 4 is a schematic diagram of a process of constructing a pearl string structure by cross arrangement of two single-chain nanoparticles, namely amino-group and carboxyl-group, in example 2 of the present invention;

FIG. 5 is a schematic view of a process of constructing a pearl string structure by connecting 5 kinds of single-chain nanoparticles end to end in example 3 of the present invention;

FIG. 6 is a TEM image of a pearl string structure constructed by connecting 5 types of single-chain nanoparticles end to end in example 3 of the present invention; microscope JEM-1011, accelerating voltage 100kV, magnification 150000 x.

FIG. 7 is a TEM image of a transmission electron microscope of the nanoparticle composite structure prepared in comparative example 1 of the present invention; a microscope JEM-1011, an accelerating voltage of 100kV and a magnification of 100000 x.

FIG. 8 is a TEM image of a single nanoparticle pendant structure prepared in comparative example 2 of the present invention; a microscope JEM-1011, an accelerating voltage of 100kV and a magnification of 80000 x.

FIG. 9 is a schematic diagram of the three single-stranded assembly structures of the present invention.

Detailed Description

Preferred embodiments of the present invention will be described in detail with reference to the following examples. It is to be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified. Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1

The embodiment provides a pendant structure constructed by single-amino single-chain nanoparticles, and a schematic diagram of a preparation process is shown in fig. 3, and the preparation method specifically comprises the following steps:

(1) synthesis of poly (4-chloromethyl styrene) main chain

Adding 20 mu L of boron trifluoride-diethyl ether complex into 5mL of super-dry dichloromethane, adding 1mL of 4-chloromethyl styrene VBC monomer under magnetic stirring, and reacting for 1h at normal temperature. Precipitating with ethanol, washing, and oven drying. The molecular weight of the polymer chain is 49.3k, and the hydrodynamic diameter is about 15 nm.

(2) Aldehyde group high molecular chain synthesis

100mg of poly (4-chloromethylstyrene) was dispersed in 30mL of dimethyl sulfoxide, and 50mg of sodium hydrogencarbonate and 100mg of potassium iodide were added thereto, followed by nitrogen gas introduction for 0.5h with stirring. Then, the mixture was put in an oil bath at 90 ℃ and reacted overnight. Precipitating in ethanol, washing with water and ethanol, and oven drying.

(3) Preparation of polystyrene ethyl trimethoxy silane single-chain nano-particles

Adding 20 mu L of boron trifluoride-diethyl ether complex into 5mL of ultra-dry dichloromethane, adding 50 mu L of p-methylstyrene under magnetic stirring, adding a mixture of 0.5mL of styrene ethyl trimethoxy silane monomer and 0.05mL of divinylbenzene crosslinking agent (the crosslinking degree is 10%) after 5min, and reacting for 1h at normal temperature; adding 1-2 drops of ethanol into the system, and carrying out sol-gel for 1 hour. Precipitating with ethanol, washing, and oven drying to obtain particles with average particle diameter of 2 nm. See fig. 2.

Adding 20 mu L of boron trifluoride-diethyl ether complex into 50mL of ultra-dry dichloromethane, adding 50 mu L of p-methylstyrene under magnetic stirring, adding a mixture of 5mL of styrene ethyl trimethoxy silane monomer and 0.5mL of divinylbenzene crosslinking agent (the crosslinking degree is 5%) after 5min, and reacting for 1h at normal temperature; adding 3-4 drops of ethanol into the system, and carrying out sol-gel for 1 hour. Precipitating with ethanol, washing, and oven drying to obtain particles with average particle diameter of 10 nm. See fig. 1.

Respectively carrying out the subsequent steps on the particles with the two particle sizes.

(4) Preparation of amino modified single-chain nanoparticles

0.2g of the nanoparticles prepared in step (3) was dissolved in 50mL of toluene, and 1mL of 3-aminopropyltriethoxysilane and 5. mu.L of acetic acid were added with stirring, and the reaction was stirred at 50 ℃ for 12 hours. Precipitating with ethanol, washing with toluene, and drying.

(5) Pendant structure preparation

Dissolving 150mg of amino modified single-chain nano-particles in 50mL of dichloromethane solvent, adding 20mg of aldehyde-based macromolecular chains, adding 10 mu L of acetic acid into the methylene-modified single-chain nano-particles, and reacting for 4 hours by using Schiff base at normal temperature; then, the system was cooled to 0 ℃, 1g of sodium borohydride was slowly added thereto, and the mixture was stirred at room temperature for 4 hours. Precipitating in ethanol, grading, washing, and preparing pendant structure.

Example 2

The embodiment provides a pearl string structure constructed by cross arrangement of two single-chain nanoparticles, namely amino and carboxyl, and a schematic diagram of a preparation process is shown in fig. 4, and the preparation method specifically comprises the following steps:

(1) preparation of poly (4-chloromethyl styrene) single-chain nanoparticles

Adding 20 mu L of boron trifluoride-diethyl ether complex into 5mL of ultra-dry dichloromethane, adding 20 mu L of p-methylstyrene under magnetic stirring, reacting at normal temperature for 5min, adding a mixture of 2mL of 4-chloromethylstyrene VBC monomer and 0.2mL of divinylbenzene DVB crosslinking agent (the crosslinking degree is 10%), reacting at normal temperature for 1h, precipitating with ethanol, washing, and drying for later use.

(2) Hydroformylation of single-chain nanoparticles

100mg of poly (4-chloromethylstyrene) single-chain nanoparticles were dispersed in 30mL of dimethyl sulfoxide, and 50mg of sodium bicarbonate and 100mg of potassium iodide were added thereto, followed by aeration with nitrogen for 0.5h under stirring. Then, the mixture was put in an oil bath at 90 ℃ and reacted overnight. Precipitating in ethanol, washing with water and ethanol, and oven drying.

(3) Preparation of sulfydryl modified single-chain nano-particles

Dissolving 50mg of aldehyde modified single-chain nano-particles in 20mL of dichloromethane, adding 30mg of mercaptoethylamine and 5 mu L of acetic acid into the dichloromethane, reacting for 4h by using normal-temperature Schiff base under the protection of nitrogen, cooling the system to 0 ℃, slowly adding 0.5g of sodium borohydride into the system, stirring and reacting for 4h at room temperature, and precipitating, grading and washing in ethanol to prepare the mercapto modified single-chain nano-particles.

(4) Preparation of amino and carboxyl modified single-chain nano-particles

20mg of thiol-modified single-chain nanoparticle toluene solution was added with 5mg of azobisisobutyronitrile AIBN and 17mg of crotonic acid, nitrogen was introduced for 0.5 hour, and then the mixture was put in a 70 ℃ oil bath and allowed to flow under nitrogen overnight to prepare carboxyl-modified single-chain nanoparticle A. Precipitating in ethanol, washing, and oven drying.

20mg of thiol-modified single-chain nanoparticle toluene solution was added with 5mg of azobisisobutyronitrile AIBN and 11mg of allylamine, nitrogen was introduced for 0.5 hour, and the mixture was put in a 70 ℃ oil bath and allowed to flow under nitrogen overnight to prepare amino-modified single-chain nanoparticle B. Precipitating in ethanol, washing, and oven drying.

(5) Preparation of pearl string structure constructed by AB particle cross arrangement

20mg of carboxyl modified single-chain nano-particle A, 2mg of dicyclohexylcarbodiimide DCC and 0.8mg of N-hydroxysuccinimide NHS are dissolved in dichloromethane, stirred at normal temperature for 15min to activate carboxyl, an equivalent amount of amino modified single-chain nano-particle B is added into the system, and the mixture reacts at normal temperature overnight to construct A, B cross-arranged pearl string structures. Precipitating with ethanol, washing, grading, and oven drying.

Example 3

The embodiment provides a pearl string structure constructed by connecting 5 single-chain nanoparticles end to end, and a schematic diagram of a preparation process is shown in fig. 5, and the preparation method specifically comprises the following steps:

(1) preparation of poly (4-chloromethyl styrene) single-chain nanoparticle a

Adding 20 mu L of boron trifluoride-diethyl ether complex into 5mL of ultra-dry dichloromethane, adding 20 mu L of p-methylstyrene under magnetic stirring, reacting at normal temperature for 5min, adding a mixture of 2mL of 4-chloromethylstyrene VBC monomer and 0.2mL of divinylbenzene DVB crosslinking agent (the crosslinking degree is 10%), and reacting at normal temperature for 1 h.

(2) Preparation of a-b nanoparticle connection structure

The same procedure as in example 2 for preparing carboxyl-modified single-chain nanoparticle a was used to prepare carboxyl-modified single-chain nanoparticle b.

And (2) adding 100mg of carboxyl modified single-chain nano-particles b into the reaction system in the step (1), and reacting for 2 hours at normal temperature by utilizing the termination reaction between carboxyl and carbocation active species to prepare the a-b single-chain nano-particle connecting structure. Precipitating with ethanol, washing, grading, and oven drying.

(3) Preparation of a-b-c nanoparticle connection structure

Amino-modified single-chain nanoparticles c were prepared using the same method as that for amino-modified single-chain nanoparticles B in example 2.

Dissolving the target product, 10mg of dicyclohexylcarbodiimide DCC and 4mg of N-hydroxysuccinimide NHS in dichloromethane in the step (2), activating carboxyl for 15min at normal temperature, adding 150mg of amino-modified single-chain nano-particles c, and performing amidation reaction overnight at normal temperature to prepare the a-b-c single-chain nano-particle connecting structure. Precipitating with ethanol, washing, grading, and oven drying.

(4) Preparation of a-b-c-d nanoparticle connection structure

Aldehyde-modified single-chain nanoparticles d were prepared using the same method as that for preparing aldehyde-modified poly (4-chloromethylstyrene) single-chain nanoparticles in example 2 (steps (1) - (2) of example 2).

And (3) dissolving 100mg of the target product in the step (3) in 50mL of dichloromethane, adding 100mg of aldehyde modified single-chain nanoparticle d and 10 mu L of acetic acid to perform Schiff base reaction at normal temperature for 4h, cooling the system to 0 ℃, slowly adding 0.5g of sodium borohydride to the system, and stirring the mixture at room temperature for reaction for 4h to prepare the a-b-c-d nanoparticle connection structure. Precipitating with ethanol, grading, washing, and oven drying.

(5) Preparation of a-b-c-d-e nanoparticle connection structure

Adding 20 mu L of boron trifluoride-diethyl ether complex into 5mL of ultra-dry dichloromethane, adding 20 mu L of p-methylstyrene under magnetic stirring, reacting at normal temperature for 5min, adding a mixture of 2mL of p-methylstyrene monomer and 0.2mL of divinylbenzene crosslinking agent (the crosslinking degree is 10%), and reacting at normal temperature for 15 min. Precipitating with ethanol, washing to obtain single-chain poly (p-methylstyrene) nanoparticles (e), and oven drying.

100mg of the target product in the step (4) and 50mg of the poly-p-methylstyrene single-chain nanoparticles e are dissolved in 50mL of N, N-dimethylformamide, 10. mu.L of 1M sodium hydroxide solution is added thereto, and the mixture is placed in an oil bath at 70 ℃ overnight to prepare five single-chain nanoparticles in a structure of end-to-end connected pearl strings, and a TEM image of which is shown in FIG. 6. Precipitating with ethanol, washing, and oven drying.

Comparative example 1

This comparative example provides a preparation of a nanoparticle string structure, which is substantially the same as the method of example 2 except that two kinds of single-chain nanoparticles with different sizes of amino group and carboxyl group modified are prepared by controlling the theoretical degree of polymerization and degree of crosslinking of the single-chain nanoparticles in step (4), i.e., an amino group modified nanoparticle a (4-5nm) and a carboxyl group modified nanoparticle B (12nm) are prepared by the same modification method starting from the single-chain nanoparticles with two sizes (4-5nm and 12nm), and finally an AB particle-linked composite structure is prepared by amidation reaction, and its TEM image is shown in fig. 7.

Because A, B particles have larger size difference, the equivalent addition required in the preparation process is difficult to be accurately controlled, and the steric hindrance effect brought by different sizes makes the preparation of the pearl string structure constructed by AB particles in a crossed arrangement impossible.

Comparative example 2

The comparative example provides a preparation method of a nanoparticle pendant structure, which is basically the same as the method of example 1, except that in step (6), the mass percent of the aldehydized polymer chains in the dichloromethane solution is 1%, the pendant structure is prepared through Schiff base reaction and reduction between amino and aldehyde groups, and a TEM image of the pendant structure is shown in FIG. 8, wherein the polymers are intertwined, and a micro-crosslinking phenomenon occurs.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.