Bottle brush polymer nanoreactor with high side chain density as well as preparation method and application of bottle brush polymer nanoreactor

Abstract

The invention discloses a bottle brush polymer nanoreactor with high side chain density as well as a preparation method and application of the bottle brush polymer nanoreactor. The preparation method of the nanoreactor comprises the following steps: preparing a bottle brush polymer skeleton with multiple functionalities by adopting small molecular monomers with different functionalities through ROMP, and growing a multi-block functional side chain with controllable molecular weight in combination with sequential ATRP living polymerization; comprising an inner block for loading a metal precursor and an outer block for providing confinement space and solubility as a protective layer. The nanoreactor can be used for in-situ synthesis of inorganic nanoparticles such as gold and ferroferric oxide, and controllable synthesis of diversified colloidal molecules is realized. According to the invention, by increasing the side chain grafting density of the bottle brush polymer and regulating and controlling the block structure, the loading efficiency of the inorganic metal precursor and the dispersity of the nanoparticles are remarkably improved, and meanwhile, the external protection block can inhibit particle aggregation, so that the monodispersed particles are suitable for the fields of catalysis, biomedicine and energy.

Description

Technical Field

[0001] The present invention relates to the technical fields of polymer chemistry and nanomaterials, and in particular to a bottlebrush polymer nano-reactor with a high side-chain density, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, bottlebrush polymer nano-reactors have made breakthrough progress in the field of controllable synthesis of inorganic nanomaterials due to their unique confinement effect and programmable chemical functions. By precisely designing the topological structure of the polymer backbone and the chemical properties of the side chains, researchers can regulate the nucleation, growth, and assembly processes of precursors, thereby achieving precise control over the size, morphology, and function of nanoparticles. Among them, cellulose-based bottlebrush polymers have become a representative system in this field due to their rich natural sources, high biocompatibility, and well-defined modifiable sites. However, limited by the chemical properties of the natural backbone, their grafting density is often fixed at 3 and it is difficult to flexibly adjust to meet diverse synthesis requirements. The grafting density not only determines the distribution density of active sites, but also regulates the geometric properties of the confined space through the arrangement of the side chains of the bottlebrush polymer, thereby affecting the diffusion and adsorption of precursors, the growth kinetics of nanoparticles, and the uniformity of nanoparticle diameters. Therefore, developing bottlebrush polymer nano-reactors with adjustable grafting density has become a key direction to break through the bottleneck of existing technologies and achieve on-demand design of nanomaterials.

[0003] Among them, ring-opening metathesis polymerization (ROMP) has become an ideal platform for constructing high-density bottlebrush polymers due to its high reaction activity, precise molecular weight control, and adjustable main-chain rigidity. In recent years, researchers have developed a series of backbone systems with different functionalities based on the ROMP reaction, and combined with the living ATRP polymerization method to achieve precise control of the molecular weight of the side chains of bottlebrush polymers. On this basis, the present invention focuses on the systematic exploration of the multi-block cooperative confinement effect of the side chains of bottlebrush polymers, and develops a class of high-density bottlebrush polymer nano-reactors. By combining multi-level confined space design (such as functional block + protective block) to optimize the reaction kinetics, precise synthesis of nanomaterials can be achieved. Summary of the Invention

[0004] Aiming at the problem that the grafting density of existing bottlebrush polymers is fixed and difficult to be flexibly adjusted, the present invention provides a bottlebrush polymer nano-reactor with a high side-chain density and a preparation method thereof, realizing precise regulation of the grafting density of bottlebrush polymers within the range of 0.5 - 6.

[0005] The preparation method steps of the bottlebrush polymer nano-reactor with a high side-chain density provided by the present invention are as follows:

[0006] S1. Synthesize small molecules NB-(C m -R) n, m takes values of 0, 2, 6 or 18, functionality n takes values of 0, 1, 2, 4 or 6, and R is Br or Cl.

[0007] Specifically, small molecules with different functionalities include 0 functionality, 1 functionality, 2 functionality, 4 functionality and 6 functionality. Among them, the small molecule with 0 functionality is: norbornene-phenyl (NB-Ph), norbornene-octadecyl (NB-C 18 ). The small molecule with 1 functionality is: norbornene-ethyl 2-bromo-2-methylpropionate (NB-C2-Br), norbornene-hexyl 2-bromo-2-methylpropionate (NB-C6-Br), norbornene-hexyl 2-chloro-2-methylpropionate (NB-C6-Cl). The small molecule with 2 functionality is: norbornene-bis[ethyl 2-bromo-2-methylpropionate] ((NB-(C2-Br)2), norbornene-bis[hexyl 2-bromo-2-methylpropionate] (NB-(C6-Br)2), norbornene-bis[ethyl 2-chloro-2-methylpropionate] (NB-(C6-Cl)2). The small molecule with 4 functionality is: norbornene-tetrakis[hexyl 2-bromo-2-methylpropionate] (NB-(C6-Br)4), norbornene-tetrakis[hexyl 2-chloro-2-methylpropionate] (NB-(C6-Cl)4). The small molecule with 6 functionality is: norbornene-hexakis[hexyl 2-bromo-2-methylpropionate] (NB-(C6-Br)6), norbornene-hexakis[hexyl 2-chloro-2-methylpropionate] (NB-(C6-Cl)6).

[0008] S2. Synthesize macromolecular skeletons P(NB-(C m -R) n with different functionalities (z = 0.5, 1, 2, 4, 6) through ring-opening metathesis polymerization (ROMP) reaction of small molecules NB-(C m -R) z ), where o is a natural number greater than 1. o

[0009] Specifically, macromolecular skeletons with different functionalities are homopolymerized from small molecules with one functionality through ring-opening metathesis polymerization reaction, or randomly copolymerized from small molecules with 0 functionality and 1 functionality, that is, the corresponding macromolecular skeleton with functionality z = 0.5.

[0010] Preferably, the functionality z of the macromolecular skeleton P(NB-(C m -R) z ) o is greater than or equal to 4.

[0011] S3. Using the macromolecular skeleton P(NB-(C m -R) z ) oTaking the backbone as the starting point, multi-block side chains are grown on the backbone in sequence through atom transfer radical polymerization (ATRP) reaction to prepare a bottlebrush polymer with a high side chain density; further, a bottlebrush polymer nano-reactor with a high side chain density is formed. The multi-block side chains include a first block side chain and a second block side chain. The first block side chain is an internal block for the growth of inorganic nanocrystals, preferably tert-butyl acrylate (PtBA) or poly(4-vinylpyridine) (P4VP). The second block side chain is a block for providing confinement and an external block for providing solubility, preferably any one of polystyrene, octadecyl methacrylate, or n-butyl acrylate.

[0012] When growing the first block side chain tert-butyl acrylate (PtBA) through atom transfer radical polymerization reaction, the reaction system adopted is: a backbone with a bromine atom at the end, that is, P(NB-(C m -R) z ) o In this formula, R is Br, the polymerization reaction monomer is tert-butyl acrylate (tBA), the initiator is a CuBr, CuBr2 / PMDETA system, and EBiB is added to monitor the degree of polymerization of the side chain; the reaction conditions are: the polymerization temperature is 65 °C, and the reaction time is 3 - 12 hours.

[0013] When growing the first block side chain poly(4-vinylpyridine) (P4VP) through atom transfer radical polymerization reaction, the reaction system adopted is: a backbone with a chlorine atom at the end, that is, P(NB-(C m -R) z ) o In this formula, R is Cl, the polymerization reaction monomer is 4-vinylpyridine (4VP), the initiator is a CuCl, CuCl2 / Me6TREN system, and ECiB is added to monitor the degree of polymerization of the side chain; the reaction conditions are: the polymerization temperature is 20 °C, and the reaction time is 6 - 24 hours.

[0014] When growing the second block side chain polystyrene (PS) through atom transfer radical polymerization reaction, the reaction system adopted is: a backbone with a chlorine atom at the end on which the first block side chain has grown, the polymerization reaction monomer is styrene (St), the initiator is a CuCl, CuCl2 / Me6TREN system, and ECiB is added to monitor the degree of polymerization of the side chain; the reaction conditions are: the polymerization temperature is 20 °C, and the reaction time is 6 - 24 hours.

[0015] When growing the second block side chain poly(octadecyl methacrylate) (PSMA) by atom transfer radical polymerization, the reaction system used is as follows: a backbone with the first block side chain grown and having a bromine atom at the end, the polymerization monomer is octadecyl methacrylate (SMA), the initiator is a CuCl, CuCl2 / DNBPY system, and EBiB is added to monitor the degree of polymerization of the side chain; the reaction conditions are: the polymerization temperature is 70 °C and the reaction time is 6 - 24 hours.

[0016] When growing the second block side chain poly(n-butyl acrylate) (PnBA) by atom transfer radical polymerization, the reaction system used is as follows: a backbone with the first block side chain grown and having a bromine atom at the end, the polymerization monomer is n-butyl acrylate (nBA), the initiator is a CuBr, CuBr2 / PMDETA system, and EBiB is added to monitor the degree of polymerization of the side chain; the reaction conditions are: the polymerization temperature is 65 °C and the reaction time is 3 - 12 hours.

[0017] When the first block side chain is poly(tert-butyl acrylate), the prepared bottlebrush polymer with a high side chain density is further dispersed in dichloromethane, and then a hydrolysis reaction is carried out under acidic conditions (adding trifluoroacetic acid) to hydrolyze the poly(tert-butyl acrylate) block to obtain a bottlebrush polymer nanoreactor with a hydrophilic PAA block. The specific hydrolysis conditions are as follows: the bottlebrush polymer is dispersed in dichloromethane with a bottlebrush polymer concentration of 1.6 mg / ml - 6.6 mg / ml, then trifluoroacetic acid is added, and the volume ratio of trifluoroacetic acid to dichloromethane is 1:3, and the reaction is stirred at room temperature (speed 200 rpm / min) for 24 h. In the obtained nanoreactor, the inorganic metal precursor is enriched in the PAA block part through electrostatic interaction.

[0018] When the first block side chain is poly(4-vinylpyridine), the prepared bottlebrush polymer with a high side chain density is directly used as a bottlebrush polymer nanoreactor. The inorganic metal precursor is enriched in the P4VP part through coordination adsorption.

[0019] The present invention also provides an application method of the bottlebrush polymer nanoreactor with the high side chain density, and the steps are as follows:

[0020] (1) Disperse the bottlebrush polymer nanoreactor with the high side chain density in DMF, add an inorganic metal precursor thereto, and stir and react at room temperature for more than 24 h to enable the metal precursor to be enriched in the first block side chain part by coordination adsorption or electrostatic interaction. The inorganic metal precursor includes but is not limited to any one of chloroauric acid trihydrate, yttrium oxide, ytterbium oxide, erbium oxide, thulium oxide, chloroplatinic acid hexahydrate, barium chloride dihydrate, titanium chloride, ferrous chloride tetrahydrate, ferric chloride hexahydrate, cadmium acetylacetonate, lead carbonate, and titanium isopropoxide.

[0021] When the first block side chain is poly(tert-butyl acrylate), the molar ratio of the inorganic metal precursor to the carboxyl functional group of the PAA block on the side chain is 1.15:1 - 10:1.

[0022] (2) Add a reducing agent or an oxidizing agent to the nano-reactor solution system enriched with the inorganic metal precursor to in-situ reduce or oxidize the inorganic precursor to generate inorganic nanoparticles. By changing the structural parameters and components of the bottlebrush polymer with a high side chain density, inorganic nanoparticles with different shapes and different types of colloidal molecules are prepared, realizing the controllable preparation of colloidal molecules.

[0023] By changing the structural parameters and components of the bottlebrush polymer with a high side chain density, different nano-reactors can be designed. For example, nano-reactors with the following several templates can be designed:

[0024] (1) P(NB-(C6-g-PtBA-b-PSt-Br) n )-b-P(NB-C 18 )-b-P(NB-(C6-g-PtBA-b-PSt-Br) n )

[0025] (2) P(NB-(C6-g-PtBA-b-PSt-Br) n )-b-P(NB-Ph)-b-P(NB-(C6-g-PtBA-b-PSt-Br) n )

[0026] (3) P(NB-(C6-g-PtBA-b-PSt-Br) n )-b-P(NB-Ph)-b-P(NB-(C6-g-PtBA-b-PSt-Br) n )-b-P(NB-Ph)-b-P(NB-(C6-g-PtBA-b-PSt-Br) n )

[0027] (4) P(NB-(C6-g-PtBA-b-PSt-Br) n )-b-P(NB-C 18 )-b-P(NB-(C6-g-PtBA-b-PSt-Br) n )-b-P(NB-C 18 )-b-P(NB-(C6-g-PtBA-b-PSt-Br) n )

[0028] The inorganic nanoparticles prepared by the above application method can be Au, upconversion particles NaYF4:Yb / Er, NaYF4:Yb / Tm, Pt, BaTiO3, semiconductor particles CdSe, thermoelectric particles PbTe, and magnetic particles Fe3O4, etc. The shapes of the nanoparticles are solid spheres, rods, linear, hollow spherical shells, rod-shaped shells, hollow linear fibers, spherical composite particles with core-shell structures, and rod-shaped composite particles with core-shell structures. Different types of colloidal molecules prepared include but are not limited to dumbbell-shaped, bead-string-shaped, nunchaku-shaped, etc.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] (1) The grafting density of traditional cellulose-based bottlebrush polymers is limited by the chemical properties of the natural skeleton and is usually fixed at 3, resulting in difficulties in further improving the loading capacity and particle size uniformity. The present invention precisely controls the density of initiation sites of the bottlebrush polymer skeleton by using different functionality small molecule monomers through ROMP reaction to construct a multi-functional macromolecular skeleton (n = 0.5, 1, 2, 4, 6), and combines ATRP technology to stepwise polymerize and grow functional blocks to achieve wide-range precise regulation of the grafting density of the side chains of the bottlebrush polymer (GD = 0.5 - 6), breaking through the limitation of GD ≤ 3 of traditional materials; moreover, ATRP living polymerization provides good control of the molecular weight (M W ), enabling the precise design of the nano-reactor structure.

[0031] (2) Existing single-block systems are prone to nanoparticle aggregation during high-temperature or long-term reactions due to the lack of protective blocks. The present invention designs the function-protection double block synergistically, combines the side chains of two functionalized blocks, uses the first block (PAA or P4VP) to efficiently load the precursor through coordination or electrostatic interaction; uses the second block (inert block PS, PSMA, PnBA) to form a confinement barrier with adjustable thickness through hydrophobic interaction or electrostatic repulsion, ensuring that the precursor concentration in the nano-space formed by the PAA block is high enough for the nucleation and growth of inorganic nanoparticles. In addition, the solubility provided by the inert block can prevent particle aggregation and maintain the monodispersity of the particles in various organic solvents. It effectively inhibits Ostwald ripening and particle diffusion.

[0032] (3) Traditional nano-reactors are mostly designed for single materials (such as gold or iron oxide), which are difficult to meet the synthesis requirements of multi-component heterojunctions. The present invention adapts to the reaction kinetics requirements of various precursors by adjusting the synergistic effect of the grafting density (GD) and the block length. It is widely applicable to the synthesis of various types of nanoparticles and colloidal molecules, and has been successfully applied to the controllable preparation of Au, Fe3O4, CdSe, and various forms of colloidal molecules.

[0033] (4) The cellulose-based framework is prone to chain entanglement or degradation under the conditions of non-polar solvents (such as toluene) or high temperatures (>150 °C), resulting in a decrease in the loading efficiency. The ROMP framework adopted in the present invention has high hydrophobicity and rigidity, and maintains structural stability in a wide temperature range (-50 to 200 °C) and various solvents (water, toluene, DMF).

[0034] (5) The present invention can synthesize high-quality core-shell nanomaterials composed of two different materials with large lattice mismatches. The present invention can overcome the necessary conditions for epitaxial growth (lattice mismatch rate less than 2%), and break through the limitations of the selection of core-shell materials for continuous epitaxial growth.

[0035] In summary, through the precise regulation of grafting density and the collaborative design of multi-blocks, the present invention significantly improves the loading efficiency, size uniformity and structural stability of the nano-reactor, breaks through the performance bottleneck of the traditional system, and provides an efficient and universal platform for the controllable preparation of diverse nanomaterials such as gold, iron oxide and core-shell heterojunctions, showing broad application prospects in the fields of catalysis, bioimaging and energy storage.

[0036] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0037] Figure 1 HNMR spectrum of the 0-functional monomer NB-Ph prepared in Example 1 1 HNMR spectrum.

[0038] Figure 2 HNMR spectrum of the 0-functional monomer NB-C prepared in Example 2 18 of 1 HNMR spectrum.

[0039] Figure 3 HNMR spectra of NB-C2-OH and the 1-functional monomer NB-C2-Br prepared in Example 3 1 HNMR spectrum.

[0040] Figure 4 HNMR spectra of NB-C6-OH and the 1-functional monomer NB-C6-Br prepared in Example 4 1 HNMR spectrum.

[0041] Figure 5 HNMR spectrum of the 1-functional monomer NB-C6-Cl prepared in Example 5 1 HNMR spectrum.

[0042] Figure 6 HNMR spectra of 2-hydroxyethyl 2-bromoisobutyrate and the 2-functional monomer NB-(C2-Br)2 prepared in Example 61 HNMR spectrum.

[0043] Figure 7 HNMR spectra of NB-(C6-OH)2 and NB-(C6-Br)2 prepared in Example 7 1 HNMR spectrum.

[0044] Figure 8 HNMR spectrum of the difunctional monomer NB-(C6-Cl)2 prepared in Example 8 1 HNMR spectrum.

[0045] Figure 9 HNMR spectra of BPA and NB-(C6-Br)4 prepared in Example 9 1 HNMR spectrum.

[0046] Figure 10 HNMR spectra of the first-step product and the final product NB-(C6-Cl)4 prepared in Example 10 1 HNMR spectrum.

[0047] Figure 11 HNMR spectrum of ECiB for monitoring ATRP with a chlorine-terminated backbone prepared in Example 11 1 HNMR spectrum.

[0048] Figure 12 Flowchart of the method for preparing gold nanorods in Example 12

[0049] Figure 13 GPC curves of P(NB-(C6-Br)4) 800 、P(NB-(C6-g-PtBA 44 -Br)4) 800 、P(NB-(C6-g-PtBA 44 -b-PSt 66 -Br)4) 800 in Example 12

[0050] Figure 14 GPC curves of P(NB-(C6-g-PtBA 44 -b-PSt 66 -Br)4) 800 、P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 in Example 12

[0051] Figure 15 DLS curves of P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4)800 UV-Vis diagram of in-situ reduction of gold nanorods in a nano-reactor.

[0052] Figure 16 is P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 SEM diagram of in-situ reduction of gold nanorods in a nano-reactor.

[0053] Figure 17 is P(NB-(C6-g-P4VP-Cl)4) 1000 、P(NB-(C6-g-P4VP-b-PSt-Cl)4) 1000 GPC curve diagram. Detailed implementation manners

[0054] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0055] Example 1

[0056] Preparation of 0-functional monomer NB-Ph:

[0057] 10 g of cis-5-norbornene-exo-2,3-dicarboxylic anhydride, 13.4 mL of aniline, and 8.5 mL of triethylamine were mixed and added to a round-bottom flask. Subsequently, 100 mL of toluene was added to the flask, and the mixture was heated to the reflux temperature of 155 °C and reacted for 12 hours. After the reflux was completed, water and toluene were removed using a water separator; then the product was cooled, and the product was recrystallized from ethanol to obtain a white solid, which is the 0-functional monomer NB-Ph. The reaction principle is as follows:

[0058]

[0059] Figure 1 is the 1 HNMR spectrum of the prepared 0-functional monomer NB-Ph, which proves the successful synthesis of NB-Ph.

[0060] Example 2

[0061] Preparation of 0-functional monomer NB-C 18 :

[0062] Add 20 g of cis-5-norbornene-exo-2,3-dicarboxylic anhydride, 32.3 g of 1-octadecylamine, and 15.0 g of 4-dimethylaminopyridine (DMAP) to a 500 mL round-bottom flask, dissolve them in 200 mL of toluene, reflux for 15 h under nitrogen protection at 150 °C, then concentrate by rotary evaporation. Wash successively with DCM, 1 M hydrochloric acid, saturated sodium bicarbonate, and saturated sodium chloride solutions in a separatory funnel, then dry with anhydrous magnesium sulfate, and concentrate by rotary evaporation to obtain purified NB-C 18 , which is a white solid. The reaction principle is as follows:

[0063]

[0064] Figure 2 is the prepared NB-C 18 of 1 1H NMR spectrum, which proves the successful synthesis of NB-C 18 .

[0065] Example 3

[0066] Preparation of 1-functional monomer NB-C2-Br:

[0067] Add 16.416 g of cis-5-norbornene-2,3-dicarboxylic anhydride, 6.01 mL of ethanolamine, and 12.22 g of 4-(dimethylamino)pyridine to a round-bottom flask, and add 100 mL of toluene thereto. Heat under reflux at 155 °C for 12 h. After the reflux is completed, remove water and toluene through a water separator, then cool the product and recrystallize it twice with toluene.

[0068] Add the product NB-C2-OH from the first-step reaction and 150 mL of NMP to an eggplant-shaped reaction flask, seal the reaction flask with a rubber stopper and evacuate and replace the gas three times to fill the flask with nitrogen; then place the reaction flask in an ice bath and slowly add 24.72 mL of 2-bromoisobutyryl bromide dropwise to the reaction flask at 0 °C (where the molar ratio of NB-C2-OH to 2-bromoisobutyryl bromide is 1:2). After reacting at 0 °C for 2 h, place the reaction flask at room temperature and react for 22 h. After the reaction is completed, place the reaction flask in an oil bath at 45 °C and react under vacuum for 12 h. After the reaction is completed, precipitate the product out in saturated sodium bicarbonate solution, and collect the product at the bottom of the centrifuge tube by centrifugation. Subsequently, wash the reaction mixture with dilute HCl solution, saturated NaHCO3 solution, and saturated NaCl solution, then dry with anhydrous MgSO4. Then remove MgSO4 through a sintered glass funnel, concentrate the product by rotary evaporation, purify the product NB-C2-Br by column chromatography, and finally dissolve the product after column chromatography in ethanol and recrystallize it three times, and filter off the ethanol to obtain NB-C2-Br.

[0069] The reaction principle is as follows:

[0070]

[0071] Figure 3 Two of the figures are the 1 HNMR spectra of the prepared NB-C2-OH and NB-C2-Br, which proves the successful synthesis of NB-C2-OH and NB-C2-Br.

[0072] Example 4

[0073] Preparation of the 1-functional monomer NB-C6-Br:

[0074] Add 20 g of cis-5-norbornene-2,3-exo-dicarboxylic anhydride, 14.02 g of 6-amino-1-hexanol, and 15.0 g of 4-dimethylaminopyridine (DMAP) to a 500 mL round-bottom flask, dissolve in 200 ml of toluene, reflux at 150 °C for 15 h under nitrogen protection, then rotary evaporate and concentrate the solution. Wash three times in a separatory funnel with DCM, 1M HCl, saturated NaHCO3, and saturated NaCl aqueous solutions in sequence, then dry with anhydrous MgSO4, and rotary evaporate and concentrate to obtain pure NB-C6-OH, which is a transparent oil.

[0075] Then place the product obtained in the previous step in a 500 mL Schlenk flask, add 100 mL of ultra-dry NMP and 48.44 g of bromoacetyl bromide dropwise under ice bath conditions, stir at room temperature for 24 h, and continue the reaction at 40 °C under vacuum for 12 h. Add the resulting brown solution to an aqueous NaHCO3 solution for precipitation, dissolve the precipitate in DCM, and then wash with 1M HCl aqueous solution, saturated NaHCO3 aqueous solution, and brine in sequence. Dry and concentrate the organic phase with anhydrous Na2SO4, and then purify by column chromatography with an eluent of Hex:EA = 6:4 to obtain pure NB-C6-Br, which is a pale yellow transparent oil.

[0076] The reaction principle is as follows:

[0077]

[0078] Figure 4 Two of the figures are the 1 HNMR spectra of the prepared NB-C6-OH and NNB-C6-Br, which proves the successful synthesis of NB-C6-OH and NB-C6-Br.

[0079] Example 5

[0080] Preparation of the 1-functional monomer NB-C6-Cl:

[0081] 6 g of NB-C6-OH was placed in a 200 mL Schlenk flask. 100 mL of ultra-dry NMP and 7.045 g of 2-chloroisobutyryl chloride were added dropwise under an ice bath condition. The mixture was stirred at room temperature for 24 h and then reacted continuously at 40 °C under vacuum for 12 h. The obtained brown solution was added to an aqueous NaHCO3 solution for precipitation. The precipitate was dissolved in DCM and then washed successively with 1 M aqueous HCl, saturated aqueous NaHCO3, and brine. The organic phase was dried with anhydrous Na2SO4 and concentrated; then it was purified by column chromatography with an eluent of Hex:EA = 6:4 to obtain pure NB-C6-Cl, which was a pale yellow transparent oil.

[0082] The reaction principle is as follows:

[0083]

[0084] Figure 5 is the 1 1H NMR spectrum of the prepared NB-C6-Cl, which proves the successful synthesis of NB-C6-Cl.

[0085] Example 6

[0086] Preparation of difunctional monomer NB-(C2-Br)2:

[0087] 45 mL of ethylene glycol, 11.8 mL of triethylamine, and 250 mL of ultra-dry THF were added to a 500 mL round-bottom flask. The air in the flask was replaced with N2. 10 mL of 2-bromoisobutyryl bromide was added under an ice bath condition. The solution became white and turbid. The reaction mixture was stirred overnight. The reaction progress was monitored by TLC until 2-bromoisobutyryl bromide was completely reacted. After the reaction was completed, the mixture was filtered to remove the insoluble white substance. The filtrate was concentrated by rotary evaporation. The obtained crude product was purified by silica gel column chromatography (the eluent was n-hexane:EA = 4:1) to finally obtain 2-hydroxyethyl 2-bromoisobutyrate as a colorless oil.

[0088] Add 1.64 g of cis-5-norbornene-exo-2,3-dicarboxylic anhydride, 5 g of 2-hydroxyethyl 2-bromoisobutyrate, and 0.28 g of 4-dimethylaminopyridine to a 50 mL round-bottom flask. Dissolve the solids in 33 mL of anhydrous DCM to give a final concentration of the anhydride of 0.3 M. Purge with N2, and add 2.88 g of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC·HCl) under stirring in an ice bath (feed ratio: 1:2.4:0.225:1.5). React in an ice bath for 2 h, then warm to room temperature and continue the reaction for 24 h. After the reaction is complete, dilute the reactants with 50 mL of DCM, and then wash with 1 M HCl solution, saturated NaHCO3 solution, and saturated NaCl solution; collect the organic phase, add anhydrous MgSO4 for drying and concentration, and purify the crude product by silica gel column chromatography (eluent: HEX:EA = 4:1) to obtain a clear oil. Recrystallize the product from ethyl acetate to obtain a white solid.

[0089] The reaction principle is as follows:

[0090]

[0091] Figure 6 The two figures respectively show the 1H NMR spectra of the prepared 2-hydroxyethyl 2-bromoisobutyrate and NB-(C2-Br)2, which proves the successful synthesis of 2-hydroxyethyl 2-bromoisobutyrate and NB-(C2-Br)2. 1 HNMR spectra of 2-hydroxyethyl 2-bromoisobutyrate and NB-(C2-Br)2, which proves the successful synthesis of 2-hydroxyethyl 2-bromoisobutyrate and NB-(C2-Br)2.

[0092] Example 7

[0093] Preparation of difunctional monomer NB-(C6-Br)2:

[0094] Add 36.04 g of 1,6-hexanediol to a 200 mL Schlenk flask, then melt it in an oil bath at 60 °C, and then add 4.92 g of cis-5-norbornene-2,3-exo-dicarboxylic anhydride and melt it in an oil bath at 100 °C. Add 74.9 mg of p-toluenesulfonic acid under stirring and react at atmospheric pressure for 4 h and then under vacuum for 18 h. Cool the solution to room temperature, dilute it with 100 mL of ethyl acetate, wash it 3 times with 150 mL of water and once with 100 mL of semi-saturated aqueous NaHCO3 solution. Collect the organic layer, dry it with anhydrous MgSO4, and concentrate it by rotary evaporation to obtain a light yellow oil of high-purity NB-(C6-OH)2.

[0095] 9.562 g of NB-(C6-OH)2 was placed in a 100 mL Schlenk flask. 50 mL of ultra-dry NMP and 22.99 g of 2-bromoisobutyryl bromide were added under ice bath conditions, and stirred at room temperature for 24 h, and then continued to react under vacuum at 40 °C for 12 h. The resulting brown solution was added to an aqueous NaHCO3 solution. The precipitate was dissolved in DCM, and then washed three times successively with 1 M HCl solution, saturated aqueous NaHCO3 solution and saturated brine. The organic phase was dried over anhydrous MgSO4 and purified by column chromatography (DCM) to obtain NB-(C6-Br)2 as a pale yellow oil.

[0096] The reaction principle is as follows:

[0097]

[0098] Figure 7 Two of the figures are the 1 1H NMR spectra of the prepared NB-(C6-OH)2 and NB-(C6-Br)2, which proves the successful synthesis of NB-(C6-OH)2 and NB-(C6-Br)2.

[0099] Example 8

[0100] Preparation of difunctional monomer NB-(C6-Cl)2:

[0101] 9.562 g of NB-(C6-OH)2 was placed in a 100 mL Schlenk flask. 50 mL of ultra-dry NMP and 14.09 g of 2-chloroisobutyryl chloride were added under ice bath conditions, and stirred at room temperature for 24 h, and then continued to react under vacuum at 40 °C for 12 h. The resulting brown solution was added to an aqueous NaHCO3 solution. The precipitate was dissolved in DCM, and then washed three times successively with 1 M HCl solution, saturated aqueous NaHCO3 solution and saturated brine. The organic phase was dried over anhydrous MgSO4 and purified by column chromatography (DCM) to obtain NB-(C6-Cl)2 as a pale yellow oil.

[0102] The reaction principle is as follows:

[0103]

[0104] Figure 8 The 1 1H NMR spectrum of the prepared NB-(C6-Cl)2, which proves the successful synthesis of NB-(C6-Cl)2.

[0105] Example 9

[0106] Preparation of tetrafunctional monomer NB-(C6-Br)4:

[0107] 5 g of bis(hydroxymethyl)propionic acid and 13 mL of triethylamine were added to a round-bottom flask and dissolved in 125 mL of dichloromethane. 11 mL of 2-bromoisobutyryl bromide was added dropwise under a nitrogen atmosphere at 0 °C. After stirring at 0 °C for 1 h, the mixture was further stirred at 25 °C for 2 h to complete the reaction. After rotary evaporation of the solvent, the residue was dissolved in diethyl ether and triethylamine hydrochloride was filtered off. Then the solution was extracted with 2 M hydrochloric acid, and the ether phase was dried over MgSO4. The solvent was evaporated to obtain a viscous liquid. The viscous liquid was stirred three times with hot water at 60 °C and then dissolved in diethyl ether again. After rotary evaporation of the ether, the crude product was recrystallized from n-hexane to obtain a white solid (BPA).

[0108] 1.35 g of BPA, 0.57 g of NB-(C6-OH)2 and 0.18 g of 4-dimethylaminopyridine p-toluenesulfonate (DPTS) were dissolved in 5 mL of DCM. After purging with nitrogen, 0.77 g of N,N'-dicyclohexylcarbodiimide (DCC) was added and the mixture was stirred at room temperature under nitrogen for 15 h. After the reaction was completed, the insoluble matter was filtered off on a glass filter lined with filter paper and rinsed with a small amount of DCM. The crude product was purified by silica gel chromatography, first eluted with n-hexane, and the polarity was gradually increased to ethyl acetate / n-hexane = 1:3 to obtain NB-(C6-Br)4 as a colorless transparent oil.

[0109] The reaction principle is as follows:

[0110]

[0111] Figure 9 The two figures are the 1 1H NMR spectra of the prepared BPA and NB-(C6-Br)4, which proves the successful synthesis of BPA and NB-(C6-Br)4.

[0112] Example 10

[0113] Preparation of 4-functional monomer NB-(C6-Cl)4:

[0114] 4 g of bis(hydroxymethyl)propionic acid and 10.4 mL of triethylamine were added to a round-bottom flask and dissolved in 125 mL of dichloromethane. 5.4 mL of 2-chloroisobutyryl chloride was added dropwise under a nitrogen atmosphere at 0 °C. After stirring at 0 °C for 1 h, the mixture was further stirred at 25 °C for 2 h to complete the reaction. After rotary evaporation of the solvent, the residue was dissolved in diethyl ether and triethylamine hydrochloride was filtered off. Then the solution was extracted with 2 M hydrochloric acid, and the ether phase was dried over MgSO4. The solvent was evaporated to obtain a viscous liquid. The viscous liquid was stirred three times with hot water at 60 °C and then dissolved in diethyl ether again. After rotary evaporation of the ether, the crude product was recrystallized from n-hexane to obtain a white solid.

[0115] Dissolve 1 g of the first-step product, 0.53 g of NB-(C6-OH)2, and 0.17 g of 4-dimethylaminopyridine tosylate (DPTS) in 5 mL of DCM. After purging with nitrogen, add 0.71 g of N,N'-dicyclohexylcarbodiimide (DCC) and stir at room temperature under nitrogen for 15 h. After the reaction is completed, filter off the insoluble matter by laying filter paper on a glass filter, and rinse with a small amount of DCM. The crude product is purified by silica gel chromatography, first eluted with n-hexane, and gradually increasing the polarity to ethyl acetate / n-hexane = 1:3 to obtain NB-(C6-Cl)4 as a colorless transparent oil.

[0116] The reaction principle is as follows:

[0117]

[0118] Figure 10 The two figures respectively show the 1 1H NMR spectra of the first-step product and the final product NB-(C6-Cl)4, which proves the successful synthesis of the first-step product and the final product NB-(C6-Cl)4.

[0119] Example 11

[0120] Preparation of ECiB for monitoring ATRP of a skeleton with a chlorine atom at the end:

[0121] Add 38 mL of ethanol, 10.6 mL of triethylamine, and 250 mL of ultra-dry THF to a 500 mL round-bottom flask, purge with N2, and add 7 mL of 2-chloroisobutyryl chloride under an ice bath. The solution becomes white and turbid. Stir the reaction mixture overnight and monitor the reaction progress by TLC until 2-chloroisobutyryl chloride reacts completely. After the reaction is completed, filter the mixture to remove the insoluble white substance, concentrate the filtrate by rotary evaporation, and purify the obtained crude product by silica gel column chromatography (eluent: n-hexane:EA = 4:1) to finally obtain ECiB as a colorless oil.

[0122] The reaction principle is as follows:

[0123]

[0124] Figure 11 is the 1 1H NMR spectrum of the prepared ECiB, which proves the successful synthesis of ECiB.

[0125] Example 12

[0126] A method for preparing gold nanorods using a bottlebrush polymer nanoreactor P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 is as follows Figure 12As shown below, the steps are as follows:

[0127] (1) In a glove box, ring-opening metathesis polymerization of norbornene-tetra[hexyl 2-bromo-2-methylpropionate] (NB-(C6-Br)4) monomer was carried out, adjusting n(MM):n(G3)=800:1, where G3 refers to the third-generation Grubbs catalyst. After reacting for 2 h, it was quenched with vinyl ethyl ether, and then precipitated three times in n-hexane and dried to obtain a poly(norbornene-tetra[hexyl 2-bromo-2-methylpropionate]) backbone, abbreviated as P(NB-(C6-Br)4). 800 Backbone.

[0128] (2) Under an argon atmosphere, 16 mg of P(NB-(C6-Br)4) backbone was added to a 50 mL Schlenk flask. 800 9.28 mL of tBA, 7.82 μL of EBiB, 0.0153 g of CuBr, 0.0048 g of CuBr2, 6.87 mL of anisole were added, and finally 26.7 μL of PMDETA was added. tert-Butyl acrylate (tBA) was polymerized by ATRP at 65 °C for 6 h. After forming the first block, unreacted monomers and EBiB-g-PtBA were washed away with n-hexane 44 and purified to obtain the bottlebrush polymer P(NB-(C6-g-PtBA 44 -Br)4). 800 .

[0129] (3) Under an argon atmosphere, 400 mg of P(NB-(C6-g-PtBA 44 -Br)4) was added to a 50 mL Schlenk flask. 800 9.6 mL of St, 10.44 μL of EBiB, 0.0204 g of CuBr, 0.0064 g of CuBr2, 7.11 mL of anisole were added, and finally 36 μL of PMDETA was added. A PS protective layer was grown by ATRP at 70 °C for 20 h. After forming the second block, unreacted monomers and EBiB-g-PSt were washed away with n-hexane 66 and purified to obtain the bottlebrush polymer P(NB-(C6-g-PtBA 44 -b-PSt 66 -Br)4). 800 .

[0130] (4) The purified bottlebrush polymer P(NB-(C6-g-PtBA 44 -b-PSt 66 -Br)4) 800Dissolved in dry dichloromethane (DCM), trifluoroacetic acid (TFA) was added, and the volume ratio of DCM / TFA was controlled to be 3. After hydrolysis for 24 h, it was concentrated by rotary evaporation and precipitated with n-hexane three times for purification to obtain the brush-shaped nanoreactor P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 .

[0131] (5) At room temperature, 10 mg of P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 nanoreactor was dissolved in 10 mL of DMF, and then 0.1733 g of HAuCl4·3H2O was added. The mixture was stirred under argon for 24 h.

[0132] (6) 0.0963 g of tert-butylamine-borane complex (TBAB) was added as a reducing agent to the reaction solution system, and then the reaction was carried out at 60 °C for 2 h. For the subsequent purification process, it was centrifuged at a low speed of 1000 rpm for 5 min to remove the precipitate. Subsequently, 50 mL of ethanol was added to the DMF solution to ensure that the PS-capped Au nanorods were completely precipitated from the solution. It was centrifuged at 5000 rpm for 5 min to remove the solvent and the precipitate, and then redispersed in toluene to obtain the finally purified Au nanorods.

[0133] The structural characterization and analysis of the nanoreactor and Au nanorods in Example 12 are as follows:

[0134] Figure 13 are the original GPC curves of P(NB-(C6-Br)4) 800 , P(NB-(C6-g-PtBA 44 -Br)4) 800 , P(NB-(C6-g-PtBA 44 -b-PSt 66 -Br)4) 800 prepared in Example 12. The figure shows that all the PDIs are less than 1.2 and are single peaks, proving the good quality of the backbone and bottle-brush polymers.

[0135] Figure 14 are the P(NB-(C6-g-PtBA 44 -Br)4) 800 , P(NB-(C6-g-PtBA 44 -b-PSt 66 -Br)4) 800 , P(NB-(C6-g-PAA 44 -b-PSt 66-Br)4) 800 The DLS curves of [P(NB-(C6-g-PtBA 44 -Br)4) 800 show that the average particle size is 63.91 nm, and for [P(NB-(C6-g-PtBA 44 -b-PSt 66 -Br)4) 800 the average particle size is 67 nm. For [P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 the average particle size is 75.2 nm. The increase in particle size proves the successful grafting of PSt and the successful hydrolysis of PtBA.

[0136] Figure 15 Figure [P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 is the UV-Vis spectrum of the in-situ reduction of gold nanorods in the nanoreactor. The figure shows obvious absorption peaks at 510 nm and 974 nm, corresponding to the short-wave transverse surface plasmon resonance absorption and the long-wave longitudinal surface plasmon resonance absorption, respectively.

[0137] Figure 16 Figure [P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 is the SEM image of the in-situ reduction of gold nanorods in the nanoreactor. The figure shows that all the gold nanorods have relatively uniform sizes and no obvious defects. The average length is 71 nm, which matches the DLS data of [P(NB-(C6-g-PAA 44 -b-PSt 66 -Br)4) 800 .

[0138] Example 13

[0139] Preparation method of the bottlebrush polymer nanoreactor P(NB-(C6-g-P4VP-b-PSt-Cl)4) with functionality 4, specifically as follows: 1000

[0140] ​(1) Norbornene-tetra[hexyl 2-chloro-2-methylpropionate] (NB-(C6-Cl)4) monomer was subjected to ring-opening metathesis polymerization in a glove box. The ratio of n(MM):n(G3) was adjusted to 1000:1. After reacting for 2 h, the reaction was quenched with vinyl ethyl ether. Subsequently, the product was precipitated three times in n-hexane and then dried to obtain poly(norbornene-tetra[hexyl 2-chloro-2-methylpropionate]) (NB-(C6-Cl) 1000 skeleton)

[0141] (2) Under an argon atmosphere, 10 mg of P(NB-(C6-Cl)4) 1000 skeleton, 5.48 mL of 4VP, 6.26 μL of ECiB, 0.0122 g of CuCl, 0.0038 g of CuCl2, 3.84 mL of anisole, and 1.64 mL of isopropanol were added to a 50 mL Schlenk flask. Finally, 18.4 μL of Me6TREN was added. ATRP polymerization was carried out at 20 °C for 2 h. After forming the first block, the unreacted monomers and ECiB-g-P4VP were washed away with n-hexane and purified to obtain the bottlebrush polymer P(NB-(C6-g-P4VP-Cl)4) 1000 .

[0142] (3) Under an argon atmosphere, 500 mg of P(NB-(C6-g-P4VP-Cl)4) 1000 , 12 mL of St, 13.05 μL of ECiB, 0.0255 g of CuCl, 0.0080 g of CuCl2, 12 mL of anisole, and 6 mL of isopropanol were added to a 50 mL Schlenk flask. Finally, 45 μL of Me6TREN was added. ATRP growth of the PS protective layer was carried out at 20 °C for 6 h. After forming the second block, the unreacted monomers and ECiB-g-PSt were washed away with n-hexane and purified to obtain the brush polymer P(NB-(C6-g-P4VP-b-PSt-Cl)4) 1000 .

[0143] Figure 17 is the P(NB-(C6-g-P4VP-Cl)4) prepared in Example 13 1000 , P(NB-(C6-g-P4VP-b-PSt-Cl)4) 1000 GPC curves. The figure shows that all the PDIs are less than 1.3 and are single peaks, proving the good quality of the bottlebrush polymers.

[0144] The bottlebrush polymer P(NB-(C6-g-P4VP-b-PSt-Cl)4) 1000 was used as a nanoreactor to prepare CsPbBr3 nanorods. The steps are as follows:

[0145] First, dissolve 10 mg of P(NB-(C6-g-P4VP-b-PSt-Cl)4) 1000 in 10 ml of anhydrous DMF and stir at room temperature for 24 hours; then add 0.34 g of CsBr and stir for 12 hours, then add 0.588 g of PbBr2 and stir for another 24 hours. After that, quickly inject 0.5 ml of the P(NB-(C6-g-P4VP-b-PSt-Cl)4) 1000 DMF solution containing the precursor into 5 ml of anhydrous toluene preheated to 50 °C to rapidly form uniform PS-coated CsPbBr3 nanorods. Subsequently, cool the toluene solution to room temperature, use toluene as a good solvent and ethyl acetate as a poor solvent, and centrifuge three times to obtain pure CsPbBr3 nanorods.

[0146] As mentioned above, it is only a preferred embodiment of the present invention and does not impose any formal restrictions on the present invention. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a bottle brush polymer nanoreactor with high side chain density, characterized in that: Here are the steps: S1. Synthesis of small molecules NB-(C m -R) n , m is 0, 2, 6 or 18, n is 0, 1, 2, 4 or 6, R is Br or Cl; S2, through different functional small molecules NB-(C m -R) n Synthesis of macromolecular skeletons P(NB-(C m -R) z ) o , z takes the value of 0.5, 1, 2, 4 or 6, and o is a natural number greater than 1; S3, with macromolecular skeleton P(NB-(C m -R) z ) o A bottle brush polymer with a high side chain density is prepared by growing multi-block side chains on the backbone through atom transfer radical polymerization reaction; a bottle brush polymer nanoreactor with a high side chain density is further formed; the multi-block side chains include a first block side chain and a second block side chain, the first block side chain is an internal block for the growth of inorganic nanocrystals, and the second block side chain is a block for providing a confinement effect and an external block for providing solubility.

2. The method for preparing a bottle brush polymer nanoreactor with high side chain density according to claim 1, characterized in that: In step S2, macromolecular skeletons with different functionalities are formed by homopolymerization of small molecules with one functionality through ring-opening metathesis polymerization or by random copolymerization of small molecules with 0 functionality and small molecules with 1 functionality.

3. The method for preparing a bottle brush polymer nanoreactor with high side chain density according to claim 1, characterized in that: In step S3, the side chain of the first block is poly-tert-butyl acrylate or poly-4-vinylpyridine.

4. The method for preparing a bottle brush polymer nanoreactor with high side chain density according to claim 1, characterized in that: In step S3, the side chain of the second block is any one of polystyrene, polyoctadecyl methacrylate or poly-n-butyl acrylate.

5. The method for preparing a bottle brush polymer nanoreactor with high side chain density as claimed in claim 3, characterized in that: In step S3, when the first block side chain is poly(tert-butyl acrylate), the obtained bottle brush polymer with high side chain density is further dispersed in dichloromethane, and then hydrolyzed under acidic conditions to obtain a bottle brush polymer nanoreactor having a hydrophilic PAA block by hydrolyzing the poly(tert-butyl acrylate) block.

6. The method for preparing a bottle brush polymer nanoreactor with high side chain density as claimed in claim 3, characterized in that: In step S3, when the side chain of the first block is poly-4-vinylpyridine, the obtained bottle brush polymer with high side chain density is directly used as a bottle brush polymer nanoreactor.

7. A bottle brush polymer nanoreactor with high side chain density, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 6.

8. A method for using the bottle brush polymer nanoreactor with high side chain density as claimed in claim 7, characterized in that: Here are the steps: (1) dispersing a bottle brush polymer nanoreactor with a high side chain density in DMF, adding an inorganic metal precursor thereto, and reacting by stirring at room temperature to allow the metal precursor to be enriched in the side chain portion of the first block by coordination adsorption or electrostatic action; the inorganic metal precursor includes but is not limited to any one of chloroauric acid trihydrate, yttrium oxide, ytterbium oxide, erbium oxide, thulium oxide, chloroplatinic acid hexahydrate, barium chloride dihydrate, titanium chloride, ferrous chloride tetrahydrate, ferric chloride hexahydrate, cadmium acetylacetonate, lead carbonate, and titanium isopropoxide; (2) Adding a reducing agent or an oxidizing agent to a nanoreactor solution system enriched with an inorganic metal precursor to in situ reduce or oxidize the inorganic precursor to generate inorganic nanoparticles; by changing the structural parameters and components of the bottle brush polymer with a high side chain density, inorganic nanoparticles of different shapes and different types of colloidal molecules are produced, thereby achieving controllable preparation of colloidal molecules.

9. The method for applying the bottle brush polymer nanoreactor with high side chain density as claimed in claim 8, characterized in that: Inorganic nanoparticles of different shapes include any one of solid spherical, rod-shaped and linear particles, hollow spherical shells, rod-shaped shells and hollow linear fibers, spherical composite particles with core-shell structures, and rod-shaped composite particles with core-shell structures.

10. The method for applying the bottle brush polymer nanoreactor with high side chain density as claimed in claim 8, characterized in that: Different types of colloidal molecules include, but are not limited to, dumbbell-shaped, bead-shaped, and nunchaku-shaped.

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