Preparation method of symmetric broken star polymer based on POSS (Polyhedral Oligomeric Silsesquioxane)

Abstract

The invention provides a preparation method of a symmetric broken star polymer based on POSS (polyhedral oligomeric silsesquioxane), and belongs to the technical field of high polymer materials. The preparation method comprises the following steps: by taking polyhedral oligomeric silsesquioxane (POSS) as a core, preparing a symmetric star-shaped POSS construction unit and an asymmetric star-shaped POSS construction unit by utilizing simple and efficient thiol-ene click reaction and Steglich esterification reaction; subsequently, a symmetric star-shaped block copolymer and an asymmetric star-shaped block copolymer are designed and prepared on the basis of a functional star-shaped POSS building unit, a new synthesis method is explored, research of the molecules is expanded, and the synthesis method has universality and can be used for large-scale preparation through accurate design.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a method for preparing a symmetry-broken star polymer based on POSS. Background Art

[0002] In the past few decades, we have witnessed the amazing creativity of the "bottom-up" strategy in exploring and synthesizing nanostructured functional materials. Most of the methods are based on amphiphilic molecules, and some such as small molecule surfactants, block copolymers and Janus particles play an important role due to their sufficient self-assembly driving force. There are also many outstanding results in this research, mainly including chemical functional groups, macromolecular structures, molecular weights and a series of other changes. By designing and synthesizing a series of macromolecular polymer materials, people aim to establish structure-property relationships to further optimize their performance. However, the performance of functional materials must rely on structures at various length scales, especially from 1 to 100nm. Correctly and precisely defined multi-level structures can achieve the effect of transferring and amplifying molecular functions on macroscopic properties. However, traditional macromolecular polymer synthesis methods are not sufficient to achieve precise control of secondary, tertiary and quaternary structures. When the structural unit size of the ordered supramolecular lattice is much larger than that of ordinary monomers, secondary interactions with sufficient energy become essential for stabilizing these structures. Therefore, it is a difficult and challenging task to accurately and simultaneously control multiple structural lengths.

[0003] POSS refers to a class of nanostructured solids with a precisely defined chemical structure (RSiO 1.5 ) n Molecular particles. Where R represents a hydrogen atom or a specific functional group, and a typical R group generally refers to a vinyl group with special reactivity. n is usually 6, 8, 10 and 12 (the main research object of this article is n = 8). Due to the three-dimensional structure, its molecular size, symmetry and surface function have different variations. Therefore, the diversity of the rigid core with symmetry and the peripheral groups distributed in three-dimensional space can provide more possibilities for this type of molecule. In addition, the rigid silica cube structure in POSS may play a specific role in aggregating a variety of functional molecules into a compact space. After development and use in recent years, POSS has become an important building block for a class of nanoscale organic / inorganic hybrid materials. These organic / inorganic hybrid materials have considerable performance in applications in various fields from soft matter to nanomedicine. At present, a large number of reports have been made on using POSS as a building block to modify it differently to achieve specific functions. However, it is still a challenge to precisely design and prepare functional materials on a large scale.

[0004] In recent years, Cheng and Zhang's research group has focused on T 8-POSS has carried out a variety of research. The most important of these is the study of T 8 -POSS surface is modified with specific functionalization to make it an excellent building block for the preparation of a variety of nano self-assembled structures, thereby realizing the application of various corresponding materials. Therefore, a variety of chemical synthesis methods, such as the ene-thiol click reaction (thiol-ene) triggered by light and heat, the azide alkyne cycloaddition reaction (CuAAC) and the Steglich esterification reaction, have been developed and widely used. However, in the synthesis of such molecules, the efficiency of chemical reactions and the diversity of prepared molecules have always been a problem that has plagued scientific researchers. At present, the more common practice is that Cheng's research group has used T 8 -POSS is a method for monofunctional modification, that is, firstly destroying the symmetry of octavinyl POSS by thiol ene click reaction to obtain monofunctionalized VPOSS-R (R is usually -OH), and then using the chemical reactivity of R to prepare a series of giant molecules. In order to reflect the direct impact of symmetry breaking on material properties, Zhang's group prepared di- and tri-addition products of octavinyl POSS (due to the spatial configuration of POSS, the di- and tri-addition products have three different regional isomers respectively), and verified the molecular structures of these regional isomers by detailed chemical characterization. The implementation of this method has brought the research on asymmetric giant molecules to a climax, and some molecules with specific asymmetric structures have been developed. However, the current research on this type of molecule is relatively single, and there is only one type of functional group with -OH to choose from, which has a great impact on the synthesis efficiency of subsequent asymmetric giant molecules. Summary of the invention

[0005] In view of this, the present invention aims to provide a method for preparing a symmetry-broken star polymer based on POSS. Starting from the symmetry of POSS, the present invention successfully prepared two types of star-shaped building blocks based on POSS by using simple and efficient thiol-ene click reaction and Steglich esterification reaction. One type starts with the symmetrical POSS core and introduces different numbers (8, 16 and 32) of alkynyl groups on its periphery by branching to form a symmetrical functionalized building block (yne) i -POSS, i=8, 16, 32). Another type of asymmetric star-shaped building blocks (yne) that can precisely control the reaction sites and regional isomerism are prepared by breaking the symmetry of POSS. i -POSS-DBCO, i=7,14). Subsequently, based on the multifunctional star-shaped POSS building block, two major types of star-shaped macromolecules were designed and successfully prepared, verifying the reactivity and universality of the above star-shaped building blocks. One type is a symmetrical star-shaped block copolymer, which combines linear block copolymers of different molecular weights with mPEGm -b-PS n -N 3 The CuAAC click reaction with the symmetric star-shaped POSS core gave symmetric star-shaped block copolymers with different arm numbers (8, 16 and 32). Another type is asymmetric star-shaped block copolymers, which are linear block copolymers of different chemical compositions, PEG m2 -N 3 and mPEG m1 -b-PS n1 -N 3 A class of asymmetric star-shaped block copolymers were prepared by sequential CuAAC and SPAAC click reactions with asymmetric star-shaped building blocks.

[0006] In order to achieve the above object, in a first aspect, the present invention provides a method for preparing a symmetrical star-shaped POSS building block, wherein the symmetrical star-shaped POSS building block (yne) 8 -POSS, (yne) 16 -POSS, (yne) 32 The synthetic route of -POSS is as follows:

[0007]

[0008] Preferably, the symmetrical star-shaped POSS building block (yne) 8 -POSS specific preparation steps are:

[0009] Under a nitrogen atmosphere, octavinyl POSS (octavinyl POSS), 2-mercaptoethanol, and azobisisobutyronitrile (azobisisobutyronitrile) are added to 140-180 mL of ultra-dry toluene, stirred at a uniform speed for 10-20 min, and then kept warm at 70-90° C. for 3-5 h, and cooled to room temperature after the reaction is completed; then toluene and excess 2-mercaptoethanol are removed to obtain a crude product; the obtained crude product is dissolved in tetrahydrofuran and precipitated and purified in ether, the ether is filtered, and the purification is repeated three times to obtain (HO) 8 -POSS;

[0010] will(HO) 8 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine (4-dimethylaminopyridine) and 90-120 mL of dry tetrahydrofuran are mixed and dissolved, and then N, N'-diisopropylcarbodiimide (N, N'-diisopropylcarbodiimide) is slowly dripped into the reaction system under ice water bath conditions, and then stirred at room temperature for 20-28 hours. After the reaction is completed, the crude product is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) is obtained. 8 -POSS;

[0011] The molar ratio of the octavinyl POSS, 2-mercaptoethanol and azobisisobutyronitrile is 1:9-12:0.2-0.4;

[0012] Said (HO) 8 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:10-15:2-4:10-15;

[0013] The eluent used in the rapid liquid preparative chromatograph is a mixture of petroleum ether and ethyl acetate in a volume ratio of 3:1.

[0014] Preferably, the symmetrical star-shaped POSS building block (yne) 16 -POSS specific preparation steps are:

[0015] will(HO) 8 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, and 4-dimethylaminopyridine are placed in a flask and 80-120 mL of dry tetrahydrofuran is added to dissolve; after they are fully dissolved, N,N′-diisopropylcarbodiimide is slowly injected into the reaction system under ice-water bath conditions, and then the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the reaction solution is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, separated and purified, dissolved in methanol, and added Carry out the deprotection reaction of hydroxyl group; after the reaction is finished, filter the remaining And washed three times with deionized water to obtain (HO) 16 -POSS;

[0016] will(HO) 16 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine and 80-120 mL of dry tetrahydrofuran are mixed and dissolved, and then N, N'-diisopropylcarbodiimide is slowly dripped into the reaction system under ice-water bath conditions, and then stirred at room temperature for 20-28 hours. After the reaction is completed, the crude product is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) is obtained. 8 -POSS;

[0017] Said (HO) 8 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, 4-dimethylaminopyridine, and N,N′-diisopropylcarbodiimide in a molar ratio of 1:10-15:2-4:10-15;

[0018] Said (HO) 16-POSS, 4-pentynoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:20-25:4-6:20-25;

[0019] The eluent used in the rapid liquid preparative chromatograph is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:1.

[0020] Preferably, the symmetrical star-shaped POSS building block (yne) 32 -POSS specific preparation steps are:

[0021] will(HO) 16 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, and 4-dimethylaminopyridine (4-dimethylaminopyridine) are placed in a flask and 20-120 mL of dry tetrahydrofuran is added to dissolve; after it is fully dissolved, N,N′-diisopropylcarbodiimide is slowly injected into the reaction system under ice-water bath conditions, and then the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the reaction solution is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, separated and purified, dissolved in methanol, and added Carry out the deprotection reaction of hydroxyl group; after the reaction is finished, filter the remaining And washed three times with deionized water to obtain (HO) 32 -POSS;

[0022] will(HO) 32 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine (4-dimethylaminopyridine) and 80-120 mL of dry tetrahydrofuran are mixed and dissolved, and then N, N'-diisopropylcarbodiimide is slowly dripped into the reaction system under ice-water bath conditions, and then stirred at room temperature for 20-28 hours. After the reaction is completed, the crude product is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) is obtained. 32 -POSS;

[0023] Said (HO) 16 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, 4-dimethylaminopyridine, and N,N′-diisopropylcarbodiimide in a molar ratio of 1:20-25:4-6:20-25;

[0024] Said (HO) 32 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:35-40:6-8:35-40;

[0025] The eluent used in the rapid liquid preparative chromatograph is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:1.

[0026] The invention modifies octavinyl POSS into a symmetrical building unit with a specific number (8, 16 and 32) of alkynyl groups on the periphery through a specific thiol-ene click reaction, a Steglich esterification reaction and a hyperbranching reaction. The molecules can undergo a CuAAC click reaction with high efficiency, and thus have particularly important applications in the preparation of giant molecules and macromolecular polymers. The specific reaction steps start from octavinyl POSS, and firstly, the octavinyl POSS is modified into a symmetrical star-shaped (HO) building unit with 8 hydroxyl groups on the periphery through a thiol-ene click reaction of 2-mercaptoethanol and octavinyl POSS. 8 -POSS, and then 4-pentynoic acid and it undergo Steglich esterification to obtain (yne) 8 -POSS. At the same time, the intermediate (HO) 8 -POSS and hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid undergo Steglich esterification and simultaneous deprotection of the hydroxyl group to obtain the branched intermediate (HO) 16 -POSS, followed by Steglich esterification with 4-pentynoic acid to obtain (yne) 16 -POSS; Repeating the hyperbranching and Steglich esterification steps can produce the product (HO) 32 -POSS and (yne) 32 -POSS.

[0027] In a second aspect, the present invention provides a method for preparing an asymmetric star-shaped POSS building block, wherein the asymmetric star-shaped POSS building block comprises: 7 -POSS-DBCO, (yne) 14 -The synthetic route of POSS-DBCO is:

[0028]

[0029] Preferably, the asymmetric star (yne) 7 -POSS-DBCO specific preparation steps are:

[0030] Octave vinyl POSS (octavinyl POSS) and 4-dimethylaminopyridine were dissolved in a beaker containing 300-350 mL of tetrahydrofuran, and then 2-mercaptoethanol was added dropwise to the beaker. After complete dissolution, the mixed solution in the beaker was placed in a desktop ultraviolet reactor at room temperature and continuously irradiated for 15-25 min; after the reaction was completed, the mixture was separated in a rapid liquid preparative chromatograph to obtain V 7POSS-OH (monohydroxy substituted heptavinyl POSS); the eluent used is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:3; wherein the molar ratio of octavinyl POSS, 4-dimethylaminopyridine, and 2-mercaptoethanol is 1:0.01-0.05:0.8-1.2;

[0031] V 7 POSS-OH and p-toluenesulfonic acid are dissolved in 40-60 mL of dry dichloromethane solvent, and then 3,4-dihydropyran is added dropwise under ice-water bath conditions, and then reacted at room temperature for 20-28 hours. After the reaction is completed, the crude product is washed with deionized water and excess solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph to obtain V after separation and purification. 7 POSS-OTHP (3,4-dihydropyran protected monohydroxy substituted heptavinyl POSS); the eluent used is a mixture of petroleum ether and ethyl acetate in a volume ratio of 10:1; wherein V 7 The molar ratio of POSS-OH, p-toluenesulfonic acid, and 3,4-dihydropyran is 1:0.8-1.2:2-3;

[0032] V 7 POSS-OTHP, 2-mercaptoethanol, and azobisisobutyronitrile are dissolved in 200-300 mL of dry toluene under a nitrogen atmosphere, and then the temperature is raised to 70-80° C. and kept warm for 20-28 hours; after the reaction is completed, the crude product is washed three times with deionized water and filtered to obtain a crude product; the obtained crude product is dried and separated in a rapid liquid preparative chromatograph to obtain (HO) 7 -POSS-OTHP; the eluent used is a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:1.5-9; wherein V 7 The molar ratio of POSS-OTHP, 2-mercaptoethanol, and azobisisobutyronitrile is 1:8-12:0.3-0.6;

[0033] will(HO) 7 -POSS-OTHP, 4-alkynylbenzoic acid, and 4-dimethylaminopyridine are dissolved in 230-270 mL of ultra-dry tetrahydrofuran, and then N,N′-diisopropylcarbodiimide is slowly injected under an ice-water bath, and then the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the reaction solution is filtered and excess solvent is removed to obtain a crude product; the crude product is separated in a rapid liquid preparative chromatograph to obtain (yne) 7 -POSS-OTHP (3,4-dihydropyran protected monohydroxy-7-alkynyl POSS); the eluent used is a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:19; wherein (HO) 7-POSS-OTHP, 4-alkynylbenzoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:7-9:7-9:7-9;

[0034] will (yne) 7 -POSS-OTHP was dissolved in 50-70 mL of a mixed solvent of dichloromethane and methanol in a volume ratio of 1:1, and an appropriate amount of p-toluenesulfonic acid was added every hour until TLC showed that the reaction was complete, and the reaction was quenched with ammonium hydroxide, and extracted with dichloromethane and deionized water, and then the excess solvent was removed to obtain a crude product; the crude product was separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) was obtained. 7 -POSS-OH (1-hydroxy-7-alkynyl POSS); the eluent used was a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:19;

[0035] Compound (yne) 7 -POSS-OH, DBCO and DPTS were placed in a flask and 20-40 mL of ultra-dry DCM was added to dissolve them, and then N,N′-diisopropylcarbodiimide was slowly injected and the reaction was continued at room temperature for 20-28 hours; after the reaction was completed, the filtrate was filtered and separated by preparative gel permeation chromatography to obtain (yne) 7 -POSS-DBCO (1-cyclooctynyl-7-alkynyl POSS); the preparative gel permeation chromatography uses tetrahydrofuran as the mobile phase; wherein (yne) 7 -POSS-OH, DBCO, DPTS, N,N

[0036] - diisopropylcarbodiimide in a molar ratio of 1:1.2-1.7:0.8-1.2:2-4.

[0037] Preferably, the asymmetric star (yne) 14 -POSS-DBCO specific preparation steps are:

[0038] will(HO) 7 -POSS-OTHP, 3,5-di(2-alkynylpropoxy)benzoic acid, and 4-dimethylaminopyridine are dissolved in 230-270 mL of ultra-dry tetrahydrofuran, and then N,N′-diisopropylcarbodiimide is slowly injected under ice-water bath conditions, and then the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the reaction solution is filtered and excess solvent is removed to obtain a crude product; the crude product is separated in a rapid liquid preparative chromatograph to obtain (yne) 14 -POSS-OTHP (3,4-dihydropyran protected monohydroxy-14-alkynyl POSS); the eluent used is a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:19; wherein (HO) 7-POSS-OTHP, 3,5-di(2-alkynylpropoxy)benzoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:7-9:7-9:7-9;

[0039] will (yne) 14 -POSS-OTHP was dissolved in 30-50 mL of a mixed solvent of dichloromethane and methanol in a volume ratio of 1:1, and an appropriate amount of p-toluenesulfonic acid was added every hour until TLC showed that the reaction was complete, and the reaction was quenched with ammonium hydroxide, and extracted with dichloromethane and deionized water, and then the excess solvent was removed to obtain a crude product; the crude product was separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) was obtained. 14 -POSS-OH (1-hydroxy-14-alkynyl POSS); the eluent used was a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:19;

[0040] Compound (yne) 14 -POSS-OH, DBCO and DPTS are placed in a flask and 15-35 mL of ultra-dry dichloromethane is added to dissolve them, then N,N′-diisopropylcarbodiimide is slowly injected and the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the filtrate is filtered and separated by preparative gel permeation chromatography to obtain (yne) 14 -POSS-DBCO (1-cyclooctynyl-14-alkynyl POSS); the preparative gel permeation chromatography uses tetrahydrofuran as the mobile phase; wherein (yne) 14 The molar ratio of POSS-OH, DBCO, DPTS and N,N′-diisopropylcarbodiimide is 1:1.2-1.7:0.8-1.2:2-4.

[0041] The present invention modifies the functional groups (hydroxyl and alkynyl) of different functions on the central core of POSS in sequence by breaking the symmetry of POSS, thereby forming an asymmetric star-shaped POSS building block. The successful preparation of such molecules makes the preparation of some asymmetric amphiphilic compounds (Janus particles and patchy particles) that were previously difficult to achieve by chemical means a reality, and modular synthesis can be performed. The specific reaction starts from octavinyl POSS, and the symmetry of the nanoparticles is adjusted by selectively converting the vinyl groups at specific vertices into different functional groups. First, the octavinyl POSS is modified into a compound (V) with 1 hydroxyl group by a thiol-ene click reaction. 7POSS-OH). Then, the remaining vinyl groups on POSS are converted to alkynyl groups through selective hydroxyl protection, thiol-ene click reaction and Steglich esterification. At the same time, the hydroxyl protection is removed and then reacted with DBCO-COOH to obtain the asymmetric star-shaped POSS building block.

[0042] In a third aspect, the present invention provides a method for preparing a symmetrical star-shaped block copolymer, comprising the following steps:

[0043] mPEG m -b-PS n -N 3 , symmetrical star-shaped POSS building blocks, CuBr, and 5-15mL of anhydrous tetrahydrofuran are mixed and dissolved; then freeze-degassed, after three cycles, PMDETA is quickly added to the reaction system under a nitrogen atmosphere using a micro-injector, and then freeze-degassed once again and reacted at room temperature for 45-52h; after the reaction is completed, the obtained solution is filtered in a silica gel column with tetrahydrofuran as an eluent to remove the metallic copper salt; finally, the obtained crude product is separated in a preparative gel permeation chromatography with tetrahydrofuran as a mobile phase to obtain a symmetrical star-shaped block copolymer;

[0044] The mPEG m -b-PS n -N 3 mPEG 43 -b-PS 35 -N 3 or mPEG 43 -b-PS 60 -N 3 ;

[0045] The symmetrical star-shaped POSS building unit is the one described in claim 1. 8 -POSS, (yne) 16 -POSS, (yne) 32 - Any of POSS;

[0046] The symmetrical star-shaped POSS building block, mPEG m -b-PS n -N 3 The molar ratio of CuBr and PMDETA is 1:12-40:0.8-1:0.8-1;

[0047] The symmetrical star-shaped block copolymer is POSS-(PS 35 -b-PEG 43 ) 8 、POSS-(PS 35 -b-PEG 43 )16 、POSS-(PS 35 -b-PEG 43 ) 32 、POSS-(PS 60 -b-PEG 43 ) 8 、POSS-(PS 60 -b-PEG 43 ) 16 、POSS-(PS 60 -b-PEG 43 ) 32 .

[0048] Preferably, the mPEG m -b-PS n -N 3 The preparation method can adopt the existing synthesis method.

[0049] The present invention combines linear block copolymers mPEG with different molecular weights m -b-PS n -N 3 Symmetric star-shaped block copolymers with different numbers of branches (8, 16, and 32) were prepared by classical CuAAC click reaction with the symmetric star-shaped POSS building blocks prepared above.

[0050] In a fourth aspect, the present invention provides a method for preparing an asymmetric star-shaped block copolymer, comprising the following steps:

[0051] PEG 114 -N 3 and the asymmetric star-shaped POSS building block were dissolved in 15-25 mL of anhydrous tetrahydrofuran and reacted at room temperature overnight; after the reaction was completed, the (yne) was separated by preparative gel permeation chromatography using tetrahydrofuran as the mobile phase. i -POSS-PEG 114 ;

[0052] mPEG 43 -b-PS 35 -N 3 、(yne) i -POSS-PEG 114 , CuBr and 8-12mL anhydrous tetrahydrofuran were mixed and dissolved and then freeze-degassed. After three cycles, PMDETA was quickly added to the reaction system under a nitrogen atmosphere using a micro-injector, and then freeze-degassed once, and reacted at room temperature for 45-52h; after the reaction was completed, it was quenched in the air, and then the metal copper salt was filtered out in a silica gel column with tetrahydrofuran as an eluent, and finally (mPEG was separated by preparative gel permeation chromatography with tetrahydrofuran as a mobile phase.43 -b-PS 35 ) i -POSS-PEG 114 ;

[0053] The asymmetric star-shaped POSS building block, mPEG 114 -N 3 The molar ratio of CuBr and PMDETA is 1:12-40:0.8-1:0.8-1;

[0054] The asymmetric star-shaped POSS building block is (yne) i -POSS-DBCO, where i=7 or 14;

[0055] The mPEG 43 -b-PS 35 -N 3 、(yne) i -POSS-PEG 114 The molar ratio of CuBr and PMDETA is 1:12-40:0.8-1:0.8-1.

[0056] Preferably, the PEG 77 -b-PS 79 -N 3 The preparation method can adopt the existing synthesis method.

[0057] The asymmetric POSS core (yne) of the present invention i -POSS-DBCO is surrounded by 7 or 14 alkyne groups and one DBCO group, which can be further used to prepare asymmetric star polymers based on POSS. First, the POSS core is reacted with the copolymer PEG m2 -N 3 Perform SPAAC reaction to generate macromolecules (yne) i -(POSS)-PEG m2 Then, through the CuAAC click reaction, another block copolymer with different chemical composition (PEG m1 -b-PS n1 -N 3 ) to form "7+1" or "14+1" type asymmetric star polymers.

[0058] The beneficial effects of the present invention include at least:

[0059] (1) Through functional modification, a precise number of alkynyl groups are introduced onto the surface of POSS to form symmetrical building units; the symmetry of POSS is selectively broken to obtain asymmetric building units with precise chemical structures containing orthogonal alkynyl functional groups.

[0060] (2) With POSS building blocks of different symmetries as the core, two types of star-shaped macromolecules were designed and prepared. One type is symmetrical star-shaped block copolymers with precise arm numbers (8, 16, and 32) and different molecular weights; the other type is hetero-arm star-shaped polymers with precise chain distribution. Through continuous click chemistry reactions, different block polymers can be modified on the POSS surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The precursor (HO) prepared in Example 1 i -VPOSS 1 H NMR characterization patterns (ab).

[0062] Figure 2 The symmetric star-shaped POSS building block obtained in Example 1 1 H NMR characterization graphs (ac), MALDI-ToF-MS characterization graph (d) and SEC characterization graph (e).

[0063] Figure 3 The symmetric star-shaped POSS building block obtained in Example 1 13 C NMR characterization patterns (ac).

[0064] Figure 4 The asymmetric star-shaped POSS building block prepared in Example 2 1 H NMR characterization patterns (ab).

[0065] Figure 5 SEC characterization diagrams (ab) of the symmetrical star-shaped block polymer prepared in Example 3.

[0066] Figure 6 The symmetrical star-shaped block polymer obtained in Example 3 1 H NMR characterization chart.

[0067] Figure 7 The asymmetric star-shaped block polymer prepared in Example 4 1 H NMR characterization chart.

[0068] Figure 8 Schematic diagram of click reaction. DETAILED DESCRIPTION

[0069] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0070] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0071] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0072] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0073] The terms "include", "including", "have", "contain", etc. used in this article are open-ended terms, which mean including but not limited to; room temperature refers to 25±2°C; all raw materials used are commercially available unless otherwise specified.

[0074] Example 1

[0075] (HO) 8 -Synthesis of POSS

[0076] Under nitrogen atmosphere, octavinyl POSS (4.0 g, 6.32 mmol), 2-mercaptoethanol (4.34 g, 52.60 mmol) and azobisisobutyronitrile (0.42 g, 2.78 mmol) were added to 160 mL of ultra-dry toluene. After stirring at a constant speed for 15 min, the temperature was raised to 80 ° C and continued to heat for 4 h, and the reaction progress was monitored by TLC. After the reaction was completed, the temperature was lowered to room temperature, and toluene and excess 2-mercaptoethanol were removed by rotary evaporator. Subsequently, the obtained crude product was uniformly dissolved in THF and purified by precipitation in ether to obtain a large amount of white solid. The ether was filtered and the process was repeated three times to obtain 2.26 g of the pure target product with a yield of 71.1%.

[0077] The chemical structure of the product is characterized as follows: 1H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ3.75(t,16H),2.75(t,16H),2.70-2.66(m,16H),1.07-1.03(m,16H).

[0078] (yne) 8 -Synthesis of POSS

[0079] Compound (HO) 8 -POSS (2.0 g, 1.59 mmol), 4-pentynoic acid (1.87 g, 19.11 mmol) and 4-dimethylaminopyridine (0.62 g, 5.10 mmol) were added to a 250 mL single-necked flask, and 100 mL of dry THF was taken from the solvent purifier to dissolve them. After they were fully dissolved, N, N

[0080] -Diisopropylcarbodiimide (2.41 g, 19.11 mmol) was slowly dripped into the reaction system under ice-water bath conditions, and then stirred at room temperature for 24 h. After the reaction was completed, the reaction solution was filtered and the excess solvent was removed, and the crude product was separated in a fast liquid preparative chromatograph, PE / EA (3 / 1, v / v) was used as the eluent, and 1.97 g of a transparent viscous liquid was obtained after separation and purification, with a yield of 65.3%.

[0081] The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ4.24(t,16H),2.75(t,16H),2.67-2.63(m,16H),2.59-2.55(m,16H),2.50-2 .47(m,16H),1.99(t,8H),1.05-1.01(m,16H).MS(MALDI-ToF,m / z):calcd.monoisotopic mass for(C 73 H 106 O 27 S 8 Si 8 ·Na) + :1919.26Da,Found:1920.34Da.

[0082] (HO) 16 -Synthesis of POSS

[0083] According to the reference, the protection yield of 2,2-bis(hydroxymethyl)propionic acid is 91.0%. Compound (HO) 8-POSS (2.0g, 1.59mmol), hydroxy-protected 2,2-bis(hydroxymethyl)propionic acid (3.33g, 19.11mmol) and 4-dimethylaminopyridine (0.62g, 5.10mmol) were weighed into a 250mL reaction flask, and 100mL of dry THF was taken from the solvent purifier to dissolve it. After it is fully dissolved, N,N′-diisopropylcarbodiimide (2.41g, 19.11mmol) is slowly injected into the reaction system under ice-water bath conditions, and then the reaction is continued at room temperature for 24h. After the reaction is completed, the reaction solution is filtered and the excess solvent is removed, and the crude product is separated in a fast liquid preparative chromatograph, PE / EA (2 / 1, v / v) is used as the eluent, and a transparent viscous liquid is obtained after separation and purification. Then, the substance is further dissolved in methanol and added (10%, w / w) for hydroxyl deprotection reaction. After the reaction is completed, filter the remaining And washed three times with deionized water to obtain 2.17 g of colorless viscous liquid with a yield of 62.5%.

[0084] The chemical structure of the product is characterized as follows: 1 H NMR (500MHz, d 4 -MeOH, ppm, 25℃): δ4.28(t,16H),3.74-3.65(m,32H),2.83(t,16H),2.78-2.74(m,16H),1.19(s,24H),1.13-1.09(m,16H). 13 CNMR(100MHz,d 4 -MeOH, ppm, 25℃), δ175.02, 64.48, 63.22, 50.21, 29.72, 25.66, 22.13, 16.12, 12.42.

[0085] (yne) 16 -Synthesis of POSS

[0086] The reaction and (yne) 8 -POSS was synthesized in a similar manner with a yield of 61.1%. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ4.31-4.23(m,48H),2.75(t,16H),2.68-2.62(m,16H),2.60-2.52 (m,32H),2.50-2.45(m,32H),1.99(t,16H),1.27(s,24H),1.06-1.02(m,16H). 13 C NMR (100 MHz, CDCl3 ,ppm,25℃),δ172.47,171.17,82.34,69.35,65.38,63.52,46.30,33.24,30.94,30 .16,26.09,17.92,14.34,14.16,13.00.MS(MALDI-ToF,m / z):calcd.monoisotopic mass for(C 152 H 200 O 60 S 8 Si 8 ·Na) + :3488.86Da,Found:3489.34Da.

[0087] (HO) 32 -Synthesis of POSS

[0088] will(HO) 16 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, and 4-dimethylaminopyridine were placed in a flask and 20 mL of dry tetrahydrofuran was added to dissolve; after they were fully dissolved, N,N′-diisopropylcarbodiimide was slowly injected into the reaction system under ice-water bath conditions, and then the reaction was continued at room temperature for 20-28 hours; after the reaction was completed, the reaction solution was filtered and the solvent was removed to obtain a crude product; the crude product was separated in a fast liquid preparative chromatograph, separated and purified, dissolved in methanol, and added Carry out the deprotection reaction of hydroxyl group; after the reaction is finished, filter the remaining And washed three times with deionized water to obtain (HO) 32 -POSS with a yield of 48.8%.

[0089] The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ4.28(t,48H),3.74-3.65(m,64H),2.83(t,16H),2.78-2.74(m,16H),1.19(s,72H),1.13-1.09(m,16H). 13 CNMR(100MHz,d 4 -MeOH, ppm, 25℃), δ175.02, 64.48, 63.22, 50.21, 29.72, 25.66, 22.13, 16.12, 12.42.

[0090] (yne) 32 -Synthesis of POSS

[0091] will(HO)32 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine and 80 mL of dry tetrahydrofuran were mixed and dissolved, and then N, N′-diisopropylcarbodiimide was slowly dripped into the reaction system under ice-water bath conditions, and then continued to stir at room temperature for 24 hours. After the reaction was completed, the crude product was filtered and the solvent was removed to obtain a crude product; the crude product was separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) was obtained. 32 -POSS;

[0092] Said (HO) 16 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, 4-dimethylaminopyridine, and N,N′-diisopropylcarbodiimide in a molar ratio of 1:20-25:4-6:20-25;

[0093] Said (HO) 32 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:35-40:6-8:35-40;

[0094] The eluent used in the rapid liquid preparative chromatograph is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:1. The yield is 46.5%.

[0095] The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ4.29-4.21(m,112H),2.78(t,16H),2.65(t,16H),2.58-2.45(m,128H),2.00(t,32H),1.26(d,72H),1.05(t,16H). 13 C NMR (100 MHz, CDCl 3 ,ppm,25℃),δ171.94,171.14,82.37,69.42,65.32,63.79,46.60,46.40,33.16,30 .26,26.18,17.87,17.73,14.32,13.06.MS(MALDI-ToF,m / z):calcd.monoisotopic mass for(C 312 H 392 O 124 S 8 Si 8 ·Na) + :6628.04Da,Found:6628.96Da.

[0096] Example 2

[0097] V 7 Synthesis of POSS-OH

[0098] Octavinyl POSS (30.0 g, 47.39 mmol) and 4-dimethylaminopyridine (0.13 g, 0.51 mmol) were dissolved in a beaker containing 350 mL of THF. Subsequently, 2-mercaptoethanol (47.39 mmol) was added dropwise to the beaker under uniform stirring. After complete dissolution, the mixed solution in the beaker was placed in a desktop UV reactor at room temperature and continuously irradiated for 20 min. After the reaction was completed, the mixture was separated in a fast liquid preparative chromatograph. When the eluent polarity was PE / EA (2 / 3, v / v), the product V was obtained. 7 POSS-OH (6.5 g, yield 18.91%).

[0099] 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ6.14-5.87(m,21H),3.75(t,2H),2.67-2.62(m,4H),1.87-1.80(m,2H),1.10-1.05(m,2H).

[0100] V 7 Synthesis of POSS-OTHP

[0101] V 7 POSS-OH (5.0mmol) and p-toluenesulfonic acid (0.57mg, 3.30mmol) were dissolved in 50mL of dry DCM solvent and stirred at a constant speed. Under ice-water bath conditions, 3,4-dihydropyran (8.0mmol) was added dropwise to the reaction solution with a disposable syringe, and then the reaction was continued at room temperature for 24h. After the reaction was completed, it was washed with a large amount of deionized water and the excess solvent was removed by a rotary evaporator. The crude product was separated in a fast liquid preparative chromatograph, PE / EA (10 / 1, v / v) was used as the eluent, and a colorless oily product was obtained after separation and purification, with a yield of 90.0%. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ6.16-5.86(m,21H),4.58(t,1H),3.87-3.78(m,2H),3.51-3.46(m,2H),2.68-2.60(m,4H),1.89-1.49(m,8H),1.10-1.05(m,2H)

[0102] (HO) 7 Synthesis of -POSS-OTHP

[0103] V 7 POSS-OH (4mmol), 2-mercaptoethanol (3.17g, 14mmol) and azobisisobutyronitrile (0.28g, 1.72mmol) were dissolved in 250mL of dry toluene under nitrogen atmosphere and stirred at a constant speed. After being fully dissolved, the temperature of the reaction system was raised to 75°C and continued for 24h. After the reaction was completed, it was washed three times with deionized water to remove unreacted 2-mercaptoethanol. At the same time, the crude product was dried and separated in a rapid liquid preparative chromatograph with THF / DCM (1 / 19-1 / 1.5, v / v) as the eluent to obtain 3.35g of a light yellow viscous liquid with a yield of 71%. The chemical structure of the product is characterized as follows: 1 H NMR (500MHz, d 6 -Acetone,ppm,25℃): δ4.59(t,1H),3.79-3.71(m,2H),3.68-3.60(m,14H),3 .49-3.43(m,2H),2.70-2.61(m,32H),1.81-1.48(m,22H),1.1-1.05(m,16H).

[0104] (yne) 7 Synthesis of -POSS-OH

[0105] will(HO) 7 -POSS-OTHP (3.0g, 1.82mmol), 4-alkynylbenzoic acid (2.41g, 13.65mmol) and 4-dimethylaminopyridine (1.67g, 13.65mmol) were dissolved in 250mL ultra-dry THF. After the reaction system was completely dissolved, N,N′-diisopropylcarbodiimide (1.72g, 13.65mmol) was slowly injected into the above reaction solution with a disposable syringe under ice-water bath conditions, and then the reaction was continued at room temperature for 24h. After the reaction was completed, the reaction solution was filtered and the excess solvent was removed, and the crude product was separated in a fast liquid preparative chromatograph, THF / DCM (0 / 1-1 / 19, v / v) was used as the elution system to obtain a light yellow viscous liquid. Then, (yne) 7 -POSS-OTHP was further dissolved in a mixed solvent of 60 mL DCM and MeOH (1 / 1, v / v) to remove THP protection. An appropriate amount of p-toluenesulfonic acid was added every hour until TLC showed that the reaction was complete, the reaction was quenched with ammonium hydroxide, and extracted with DCM and deionized water. After removing the excess solvent, the crude product was separated in a fast liquid preparative chromatograph with THF / DCM (1 / 19, v / v) as the elution system. After separation and purification, a colorless viscous liquid was obtained with a yield of 88.0%. The chemical structure of the product is characterized as follows: 1 H NMR (500MHz, d6 -Acetone,ppm,25℃): δ8.0-7.97(m,14H),7.00-6.98(m,14H),4.73-4.71(m,14H),4.38-4.34(m,14H),3.73 -3.69(m,2H),2.66-2.59(m,32H),2.55(s,7H),2.03-1.99(m,14H),1.83-1.77(m,2H),1.05-1.01(m,16H).

[0106] (yne) 7 -Synthesis of POSS-DBCO

[0107] Compound (yne) 7 -POSS-OH (1.25g, 0.46mmol), DBCO (0.21g, 0.69mmol) and DPTS (0.1g, 0.46mmol) were weighed into a 50mL single-necked flask, and 30mL of ultra-dry DCM was taken from the solvent purifier to dissolve it. After it was fully dissolved, N,N′-diisopropylcarbodiimide (0.17g, 1.38mmol) was slowly injected into the reaction solution, and the reaction was continued at room temperature for 24h. After the reaction was completed, the filtrate was filtered and separated by preparative gel permeation chromatography (THF as mobile phase) to obtain 1.0g of yellow viscous liquid, with a yield of 71.5%. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃):7.65-7.22(m,22H),6.77-6.75(m,7H),4.87-4.68(m,30H),4.49-4.33(m,16H),2.88-2.54(m,60H),1.09(t,16H).

[0108] Example 3

[0109] mPEG 43 Synthesis of -Br

[0110] mPEG 43 -OH(M n=1900g / mol, 19.0g, 10.0mmol) was dissolved in 250mL dry DCM. After 15min, 5mL DCM diluted 2-bromoisobutyryl bromide (6.90g, 30.0mmol) was slowly injected with a disposable syringe under ice water bath conditions. Then continue to stir at room temperature for 36h, and the solution changes from transparent to dark yellow. After the reaction is complete, a small amount of deionized water is injected into the reaction system to quench the excess 2-bromoisobutyryl bromide. At the same time, it is washed three times with a large amount of DCM. The obtained brown mixed solution is slowly dripped into a large amount of ice ether for precipitation, the obtained product is filtered and purified three times by recrystallization in a small amount of n-hexane to obtain 17.62g of light gray target product with a yield of 86.0%. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃):δ4.30-4.28(m,2H),3.71-3.69(m,2H),3.62-3.42(m,173H),3.34(s,3H),1.91(s,6H).SEC(THF,RI,40℃):M n =2700g / mol,

[0111] mPEG 43 -b-PS 35 Synthesis of -Br

[0112] mPEG 43 -Br (Mn = 1.9kg / mol, 2.05g, 1.0mmol), styrene (7.50g), CuBr (143.45mg) and 6mL ultra-dry toluene were added to a Schlenk reaction bottle equipped with a magnet and stirred at a constant speed. When the reactants were completely dissolved, the mixture was placed on a double-row tube for freeze degassing. After three cycles, PMDETA (0.21g) was quickly added to the reaction system under a nitrogen atmosphere. After an additional freeze degassing, the mixture in the system was thawed at room temperature and placed in a 90°C oil bath for different reaction times. After the reaction was completed, the reaction was terminated by freezing with liquid nitrogen. The resulting solution was filtered through a silica gel column to remove the metal copper salt and precipitated three times in a large amount of ice n-hexane to obtain 2.68g of white solid powder. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃):δ7.11-6.59(m,173H),3.68-3.55(m,173H),3.39(s,3H),2.22-1.44(m,84H),0.97-0.84(m,6H).SEC(THF,RI,40℃):M n =7200g / mol,

[0113] mPEG 43 -b-PS 35 -N 3 Synthesis

[0114] Add mPEG into a 25 mL single-necked flask with a magnetic stirrer. 43 -b-PS 35 -Br(M n mPEG=1.9kg / mol,M n PS = 3.6 kg / mol, 2.68 g, 0.49 mmol), sodium azide (0.31 g, 4.90 mmol) and 10 mL of anhydrous DMF. After stirring at room temperature for 48 h, a small amount of deionized water was used to dissolve the unreacted sodium azide, and a large amount of CHCl was added. 3 Wash three times, let stand at room temperature to separate the phases, and the obtained organic phase is washed with anhydrous Na 2 SO 4 After removing most of the solvent by rotary evaporator, 2.28 g of white solid powder was obtained by precipitation in a large amount of ice n-hexane three times, i.e. mPEG. 43 -b-PS 35 -N 3 , with a yield of 85.0%.

[0115] The chemical structure of the product is characterized as follows: FT-IR: 2105(-N 3 ).SEC(DMF,RI,40℃):M n =2500g / mol,

[0116] mPEG 43 -b-PS 60 The chemical structure of -Br is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃): δ7.09-6.47(m,298H),3.69-3.55(m,173H),3.39(s,3H),2.22-1.44(m,179H),0.97-0.84(m,6H).SEC(THF,RI,40℃):M n =9500g / mol, 1.06.

[0117] mPEG 43 -b-PS 60 -N 3 The chemical structure of3 ).SEC(DMF,RI,40℃):M n =3000g / mol,

[0118] POSS-(PS 35 -b-PEG 43 ) 8 Synthesis

[0119] mPEG 43 -b-PS 35 -N 3 (M n mPEG=1.9kg / mol,M n PS=3.6kg / mol, 1.74g, 0.32mmol), (yne) 8 -POSS (0.05g, 0.026mmol), CuBr (45.38mg) and 10mL of anhydrous THF were added to a Schlenk reaction bottle equipped with a magnet and stirred for 5min to fully dissolve it. The mixture was then placed on a double-row tube for freeze degassing. After three cycles, PMDETA (54.83mg) was quickly added to the reaction system under a nitrogen protection atmosphere using a microinjector. After an additional freeze degassing, the reaction bottle was placed at room temperature for reaction for 48h. After the reaction was completed, the resulting solution was filtered in a silica gel column with THF as the eluent to remove the metallic copper salt. Finally, the crude product was separated in a preparative gel permeation chromatography (THF as the mobile phase) to obtain 0.59g of a light yellow foamy solid with a yield of 49.5%. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃):δ7.37(triazole),7.09-6.39(PS),3.71-3.47(mPEG).SEC(DMF,RI,40℃):M n =22600 g / mol,

[0120] POSS-(PS 35 -b-PEG 43 ) 16 Synthesis

[0121] The reaction and POSS-(PS 35 -b-PEG 43 ) 8 The synthetic steps of are similar, and the yield is 45.1%. The chemical structure of the product is characterized as follows: 1H NMR (500MHz, CDCl3, ppm, 25℃): δ7.37 (triazole), 7.09-6.39 (PS), 3.71-3.47 (mPEG). SEC (DMF, RI, 40℃): M n =32300 g / mol,

[0122] POSS-(PS 35 -b-PEG 43 ) 32 Synthesis

[0123] The reaction and the target product POSS-(PS 35 -b-PEG 43 ) 8 The synthetic steps are similar to those of , with a yield of 39.8%. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃):δ7.37(triazole),7.09-6.39(PS),3.71-3.47(mPEG).SEC(DMF,RI,40℃):M n =49200 g / mol, PDI = 1.07.

[0124] Another symmetrical star block copolymer POSS-(PS 35 -b-PEG 43 ) 8 / 16 / 32 (M n mPEG=1900g / mol,M n PS=6200g / mol) and its intermediates are characterized as follows: POSS-(PS 60 -b-PEG 43 ) 8 :SEC(DMF,RI,40℃):M n =28700g / mol,PDI=1.05POSS-(PS 60 -b-PEG 43 ) 16 :SEC(DMF,RI,40℃):M n =40400g / mol,PDI=1.05.

[0125] POSS-(PS 60 -b-PEG 43 ) 32 :SEC(DMF,RI,40℃):M n =61800 g / mol, PDI = 1.08.

[0127] Example 4

[0128] Asymmetric POSS core (yne) i -POSS-DBCO is surrounded by 7 or 14 alkyne groups and one DBCO group, which can be further used to prepare asymmetric star polymers based on POSS. First, the POSS core is bonded to the block copolymer PEG m2 -N 3 Perform SPAAC reaction to generate macromolecules (yne) i -POSS-PEG m2 Then, through the CuAAC click reaction, another block copolymer with different chemical composition (PEG m1 -b-PS n1 -N 3 ) to form a "7+1" or "14+1" type asymmetric star polymer. Taking the "14+1" type asymmetric star polymer as an example, the detailed synthesis is as follows:

[0129] mPEG 114 Synthesis of -Br

[0130] The reaction and sample mPEG 43 The synthesis method of -Br is similar. The chemical structure of the product is characterized as follows: 1 H NMR (500 MHz, CDCl 3 ,ppm,25℃):δ3.84-3.28(m,309H),1.91(s,6H).SEC(THF,RI,40℃):M n =6200g / mol,

[0131] PEG 114 -N 3 Synthesis

[0132] mPEG 114 -Br(M n=6.2kg / mol, 0.62g, 0.1mmol), styrene (2.08g), CuBr (14.3mg) and 1.0g anhydrous toluene were added to a Schlenk reaction bottle equipped with a magnet and stirred for 5min. When the reactants were completely dissolved, the mixture was placed on a double-row tube for freeze degassing. After three cycles, PMDETA (17.3mg) was quickly added to the reaction system under a nitrogen atmosphere. After an additional freeze degassing, the reaction bottle was reacted at 100°C for different times. After the reaction was completed, the reaction was terminated by freezing with liquid nitrogen, and the resulting solution was filtered through a silica gel column to remove the metallic copper salt. Finally, the resulting solution was precipitated three times in a large amount of ice n-hexane to obtain a white solid powder. At the same time, the resulting white solid powder was dissolved in 5mL DMF and 50mg NaN 3 The reaction was continued at room temperature for 36 h. After the reaction was completed, a large amount of CHCl 3 and a small amount of deionized water for three times, the organic phases were combined and washed with anhydrous Na 2 SO 4 After drying overnight, most of the solvent was removed and precipitated in a large amount of ice-cold n-hexane three times to obtain 0.7 g of white solid powder, i.e. mPEG. 114 -N 3 .

[0133] Compound(yne) 14 -POSS-PEG 114 Synthesis

[0134] PEG 114 -N 3 (M n PEG = 6.2 kg / mol 0.42 g, 0.068 mmol) and (yne) 14 -POSS-DBCO (0.31 g, 0.1 mmol) was dissolved in 20 mL of anhydrous THF and reacted overnight at room temperature. After the reaction was completed, 0.83 g of a white foamy solid was separated by preparative gel permeation chromatography (THF as mobile phase) with a yield of 82.8%. The chemical structure of the product is characterized as follows: 1 HNMR (500MHz, CDCl 3 ,ppm,25℃):δ7.52-7.42(DBCO),3.83-3.30(PEG).SEC(THF,RI,40℃):M n =9400g / mol,

[0135] (mPEG 43 -b-PS 35 ) 14 -POSS-PEG 114 Synthesis

[0136] mPEG 43 -b-PS 35 -N 3 (M n PEG=1.9kg / mol,M n PS=3.6kg / mol, 1.57g, 0.29mmol), (yne) 14 -POSS-PEG 114 (0.12g, 0.013mmol), CuBr (40.0mg) and 10mL of anhydrous THF were added to the Schlenk reaction flask and stirred for 5min. When the reactants were completely dissolved, the mixture was placed on a double-row tube for freeze degassing. After three cycles, PMDETA (48mg) was quickly added to the reaction system under a nitrogen atmosphere. After an additional freeze degassing, the reaction flask was placed at room temperature for 48h. After the reaction was completed, the reaction system was exposed to air for quenching, and the resulting solution was filtered in a silica gel column with THF as the eluent to remove the metallic copper salt. Finally, the crude product was separated in preparative gel permeation chromatography (THF as the mobile phase) to obtain 0.43g of a white solid powder with a yield of 59.4%. The chemical structure of the product is characterized as follows: 1 HNMR (500MHz, CDCl 3 ,ppm,25℃):δ7.52-7.42(DBCO),7.25-6.38(PS,triazole),3.83-3.30(PEG).SEC(DMF,RI,40℃):M n =30500g / mol,

[0137] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a symmetrical star-shaped POSS building block, characterized in that: Symmetrical star-shaped POSS building block (yne) 8-POSS, (yne) 16 -POSS, (yne) 32 The synthetic route of -POSS is as follows:

2. The preparation method according to claim 1, characterized in that: The specific preparation steps of the symmetrical star-shaped POSS building block (yne) 8-POSS are: Under a nitrogen atmosphere, octavinyl POSS, 2-mercaptoethanol, and azobisisobutyronitrile are added to 140-180 mL of ultra-dry toluene, stirred at a uniform speed for 10-20 min, and then kept warm at 70-90° C. for 3-5 h, and cooled to room temperature after the reaction is completed; then toluene and excess 2-mercaptoethanol are removed to obtain a crude product; the obtained crude product is dissolved in tetrahydrofuran and purified by precipitation in ether, the ether is filtered, and the purification is repeated three times to obtain (HO)8-POSS; (HO)8-POSS, 4-pentynoic acid, 4-dimethylaminopyridine and 90-120 mL of dry tetrahydrofuran are mixed and dissolved, and then N,N′-diisopropylcarbodiimide is slowly dripped into the reaction system under ice-water bath conditions, and then stirred at room temperature for 20-28 hours. After the reaction is completed, the crude product is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, and (yne)8-POSS is obtained after separation and purification; The molar ratio of the octavinyl POSS, 2-mercaptoethanol and azobisisobutyronitrile is 1:9-12:0.2-0.4; The molar ratio of (HO)8-POSS, 4-pentynoic acid, 4-dimethylaminopyridine and N,N′-diisopropylcarbodiimide is 1:10-15:2-4:10-15; The eluent used in the rapid liquid preparative chromatograph is a mixture of petroleum ether and ethyl acetate in a volume ratio of 3:

1.

3. The preparation method according to claim 1, characterized in that: The symmetrical star-shaped POSS building block (yne) 16 -POSS specific preparation steps are: (HO)8-POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid and 4-dimethylaminopyridine are placed in a flask and 80-120 mL of dry tetrahydrofuran is added to dissolve; after they are fully dissolved, N,N′-diisopropylcarbodiimide is slowly injected into the reaction system under ice-water bath conditions, and then the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the reaction solution is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, separated and purified, dissolved in methanol, and added Carry out the deprotection reaction of hydroxyl group; after the reaction is finished, filter the remaining And washed three times with deionized water to obtain (HO) 16 -POSS; will(HO) 16 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine and 80-120 mL of dry tetrahydrofuran are mixed and dissolved, and then N, N'-diisopropylcarbodiimide is slowly dripped into the reaction system under ice-water bath conditions, and then stirred at room temperature for 20-28 hours. After the reaction is completed, the crude product is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) 8-POSS is obtained; The molar ratio of (HO)8-POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, 4-dimethylaminopyridine, and N,N′-diisopropylcarbodiimide is 1:10-15:2-4:10-15; Said (HO) 16 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:20-25:4-6:20-25; The eluent used in the rapid liquid preparative chromatograph is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:

1.

4. The preparation method according to claim 1, characterized in that: The symmetrical star-shaped POSS building block (yne) 32 -POSS specific preparation steps are: will(HO) 16 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, and 4-dimethylaminopyridine (4-dimethylaminopyridine) are placed in a flask and 20-120 mL of dry tetrahydrofuran is added to dissolve; after it is fully dissolved, N,N′-diisopropylcarbodiimide is slowly injected into the reaction system under ice-water bath conditions, and then the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the reaction solution is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, separated and purified, dissolved in methanol, and added Carry out the deprotection reaction of hydroxyl group; after the reaction is finished, filter the remaining And washed three times with deionized water to obtain (HO) 32 -POSS; will(HO) 32 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine and 80-120 mL of dry tetrahydrofuran are mixed and dissolved, and then N, N′-diisopropylcarbodiimide is slowly dripped into the reaction system under ice-water bath conditions, and then stirred at room temperature for 20-28 hours. After the reaction is completed, the crude product is filtered and the solvent is removed to obtain a crude product; the crude product is separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) is obtained. 32 -POSS; Said (HO) 16 -POSS, hydroxyl-protected 2,2-bis(hydroxymethyl)propionic acid, 4-dimethylaminopyridine, and N,N′-diisopropylcarbodiimide in a molar ratio of 1:20-25:4-6:20-25; Said (HO) 32 -POSS, 4-pentynoic acid, 4-dimethylaminopyridine, N,N′-diisopropylcarbodiimide in a molar ratio of 1:35-40:6-8:35-40; The eluent used in the rapid liquid preparative chromatograph is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:

1.

5. A method for preparing an asymmetric star-shaped POSS building block, characterized in that: Asymmetric star (yne) 7-POSS-DBCO, (yne) 14 -The synthetic route of POSS-DBCO is:

6. The preparation method according to claim 5, characterized in that: The specific preparation steps of the asymmetric star-shaped (yne) 7-POSS-DBCO are: Dissolve octavinyl POSS and 4-dimethylaminopyridine in a beaker filled with 300-350 mL of tetrahydrofuran, then add 2-mercaptoethanol dropwise into the beaker. After complete dissolution, place the mixed solution in the beaker in a desktop UV reactor at room temperature and continuously irradiate for 15-25 min. After the reaction is completed, separate the mixture in a fast liquid preparative chromatograph to obtain V7POSS-OH. The eluent used is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:

3. The molar ratio of octavinyl POSS, 4-dimethylaminopyridine and 2-mercaptoethanol is 1:0.01-0.05:0.8-1.

2. Dissolve V7POSS-OH and p-toluenesulfonic acid in 40-60 mL of dry dichloromethane solvent, then add 3,4-dihydropyran dropwise under ice-water bath conditions, react at room temperature for 20-28 hours, wash with deionized water after the reaction is completed and remove excess solvent to obtain a crude product; separate the crude product in a fast liquid preparative chromatograph, and obtain V7POSS-OTHP after separation and purification; the eluent used is a mixture of petroleum ether and ethyl acetate in a volume ratio of 10:1; wherein the molar ratio of V7POSS-OH, p-toluenesulfonic acid, and 3,4-dihydropyran is 1:0.8-1.2:2-3; Dissolve V7POSS-THP, 2-mercaptoethanol and azobisisobutyronitrile in 200-300 mL dry toluene under nitrogen atmosphere, then heat to 70-80°C and keep warm for 20-28 hours; after the reaction is completed, wash with deionized water three times and filter to obtain a crude product; dry the obtained crude product and separate it in a fast liquid preparative chromatograph to obtain (HO)7-POSS-OTHP; the eluent used is a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:1.5-1.9; wherein the molar ratio of V7POSS-OTHP, 2-mercaptoethanol and azobisisobutyronitrile is 1:8-12:0.3-0.6; Dissolve (HO)7-POSS-OTHP, 4-alkynylbenzoic acid and 4-dimethylaminopyridine in 230-270 mL of ultra-dry tetrahydrofuran, then slowly inject N,N′-diisopropylcarbodiimide in an ice-water bath, and then continue to react at room temperature for 20-28 hours; after the reaction is completed, filter the reaction solution and remove excess solvent to obtain a crude product; separate the crude product in a fast liquid preparative chromatograph to obtain (yne)7-POSS-OTHP; the eluent used is a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 0-1-1:19; wherein the molar ratio of (HO)7-POSS-OTHP, 4-alkynylbenzoic acid, 4-dimethylaminopyridine and N,N′-diisopropylcarbodiimide is 1:7-9:7-9:7-9; Dissolve (yne)7-POSS-OTHP in 50-70 mL of a mixed solvent of dichloromethane and methanol in a volume ratio of 1:1, add an appropriate amount of p-toluenesulfonic acid every hour until thin layer chromatography shows that the reaction is complete, quench the reaction with ammonium hydroxide, extract with dichloromethane and deionized water, and then remove excess solvent to obtain a crude product; separate the crude product in a fast liquid preparative chromatograph, separate and purify to obtain (yne)7-POSS-OH; the eluent used is a mixed solution of tetrahydrofuran and dichloromethane in a volume ratio of 1:19; Compound (yne)7-POSS-OH, DBCO and DPTS are placed in a flask, 20-40 mL of ultra-dry dichloromethane is added to dissolve them, and then N,N′-diisopropylcarbodiimide is slowly injected, and the reaction is continued at room temperature for 20-28 hours; after the reaction is completed, the filtrate is filtered and separated by preparative gel permeation chromatography to obtain (yne)7-POSS-DBCO (1-cyclooctynyl-7-alkynyl POSS); the preparative gel permeation chromatography uses tetrahydrofuran as a mobile phase; wherein the molar ratio of (yne)7-POSS-OH, DBCO, DPTS, and N,N′-diisopropylcarbodiimide is 1:1.2-1.7:0.8-1.2:2-4; Dissolve (HO)7-POSS-OTHP, 3,5-di(2-alkynylpropoxy)benzoic acid and 4-dimethylaminopyridine in 230-270 mL of ultra-dry tetrahydrofuran, then slowly inject N,N′-diisopropylcarbodiimide in an ice-water bath, and then continue to react at room temperature for 20-28 hours; after the reaction is completed, filter the reaction solution and remove excess solvent to obtain a crude product; separate the crude product in a rapid liquid preparative chromatograph to obtain (yne) 14 -POSS-OTHP; the eluent used is a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:19; wherein the molar ratio of (HO)7-POSS-OTHP, 3,5-di(2-alkynylpropoxy)benzoic acid, 4-dimethylaminopyridine, and N,N′-diisopropylcarbodiimide is 1:7-9:7-9:7-9; will (yne) 14 -POSS-OTHP was dissolved in 30-50 mL of a mixed solvent of dichloromethane and methanol in a volume ratio of 1:1, and an appropriate amount of p-toluenesulfonic acid was added every hour until TLC showed that the reaction was complete, and the reaction was quenched with ammonium hydroxide, and extracted with dichloromethane and deionized water, and then the excess solvent was removed to obtain a crude product; the crude product was separated in a fast liquid preparative chromatograph, and after separation and purification, (yne) was obtained. 14 -POSS-OH; the eluent used was a mixture of tetrahydrofuran and dichloromethane in a volume ratio of 1:19; Compound (yne) 14 -POSS-OH, DBCO and DPTS were placed in a flask and 15-35 mL of ultra-dry DCM was added to dissolve them, and then N,N′-diisopropylcarbodiimide was slowly injected and the reaction was continued at room temperature for 20-28 hours; after the reaction was completed, the filtrate was filtered and separated by preparative gel permeation chromatography to obtain (yne) 14 -POSS-DBCO; the preparative gel permeation chromatography uses tetrahydrofuran as the mobile phase; wherein (yne) 14 The molar ratio of POSS-OH, DBCO, DPTS and N,N′-diisopropylcarbodiimide is 1:1.2-1.7:0.8-1.2:2-4.

7. A method for preparing a symmetrical star-shaped block copolymer, characterized in that: The following steps are involved: mPEG m -b-PS n -N3, symmetrical star-shaped POSS building blocks, CuBr, and 8-10 mL of anhydrous tetrahydrofuran are mixed and dissolved; then freeze-degassed, after three cycles, N,N,N′,N′,N′-pentamethyldiethylenetriamine is quickly added to the reaction system under a nitrogen atmosphere using a microinjector, and then freeze-degassed once and reacted at room temperature for 45-52 hours; after the reaction is completed, the obtained solution is filtered in a silica gel column with tetrahydrofuran as an eluent to remove the metallic copper salt; finally, the obtained crude product is separated in a preparative gel permeation chromatography with tetrahydrofuran as a mobile phase to obtain a symmetrical star-shaped block copolymer; The mPEG m -b-PS n -N3 is mPEG 43 -b-PS 35 -N3 or mPEG 43 -b-PS 60 -N3; The symmetrical star-shaped POSS building block is the (yne)8-POSS, (yne) 16 -POSS, (yne) 32 - Any of POSS; The symmetrical star-shaped POSS building block, mPEG m -b-PS n -The molar ratio of N3, CuBr, and PMDETA is 1:12-40:0.8-1:0.8-1; The symmetrical star-shaped block copolymer is POSS-(PS 35 -b-PEG 43 )8.POSS-(PS 35 -b-PEG 43 ) 16 、POSS-(PS 35 -b-PEG 43 ) 32 、POSS-(PS 60 -b-PEG 43 )8.POSS-(PS 60 -b-PEG 43 ) 16 、POSS-(PS 60 -b-PEG 43 ) 32 .

8. A method for preparing an asymmetric star-shaped block copolymer, characterized in that: The following steps are involved: PEG 114 -N3 and the asymmetric star-shaped POSS building block were dissolved in 15-25 mL of anhydrous tetrahydrofuran and reacted at room temperature overnight; after the reaction was completed, preparative gel permeation chromatography using tetrahydrofuran as the mobile phase was used to separate (yne) i -POSS-PEG 114 ; mPEG 43 -b-PS 35 -N3, (yne) i -POSS-PEG 114 , CuBr and 8-12mL anhydrous THF were mixed and dissolved and then freeze-degassed. After three cycles, PMDETA was quickly added to the reaction system under a nitrogen atmosphere using a micro-injector, and then freeze-degassed once, and reacted at room temperature for 45-52h; after the reaction was completed, it was quenched in the air, and then the metal copper salt was filtered out in a silica gel column with tetrahydrofuran as the eluent, and finally (mPEG was separated by preparative gel permeation chromatography with tetrahydrofuran as the mobile phase. 43 -b-PS 35 ) i -POSS-PEG 114 ; The asymmetric star-shaped POSS building block, PEG 114 -The molar ratio of N3 is 1:1.5-2.0; The asymmetric star-shaped POSS building block is (yne) i -(POSS)-DBCO, where i=7 or 14; described i -POSS-PEG 114 、mPEG 43 -b-PS 35 -The molar ratio of N3, CuBr and PMDETA is 1:12-20:0.8-1:0.8-1.

Images