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Gold nanoparticle with core-shell structure and preparation method thereof

A gold nanoparticle, core-shell structure technology, applied in the field of nanomaterials, can solve the problems of poor stability and solubility, no stability factor, wide size distribution of gold nanoparticles, etc., and achieve good stability and good temperature responsiveness. Effect

Active Publication Date: 2013-11-13
CHANGZHOU INST OF ENERGY STORAGE MATERIALS &DEVICES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

"Graft from" mainly uses the method of surface-initiated polymerization to make monomers aggregate and grow on the surface of gold particles. For example, Li et al. obtained temperature-responsive core-shell gold nanoparticles through the "graft from" method, but this method Not only does it need to synthesize an initiator for ligand exchange with nanoparticles and also as an initiator for initiating polymerization, but it also requires the use of highly toxic ligands and catalysts, and the polymerization process itself is cumbersome.
"Graft to" is mainly to directly bond polymers to the surface of gold nanoparticles. For example, Tenhu et al. prepared temperature-responsive core-shell gold nanoparticles in situ through the "graft to" method. The preparation process is simple and at the same time The molecular weight of the polymer can be controlled as expected, but the size of the nanoparticles cannot be well controlled by in situ reduction, and the size distribution of the obtained gold nanoparticles is relatively wide
[0005] At present, Zhu et al. have improved the preparation method of Tenhu et al., using the "graft to" method, by exchanging a temperature-responsive polymer with a sulfhydryl group at the end and a pre-synthesized gold nanoparticle to obtain a temperature Responsive core-shell structure gold nanoparticles overcome the shortcomings of the in situ preparation method, but since this method only protects the gold nanoparticles through the homopolymeric polymer (PNIPAM), there are no other stability factors, so the prepared core Shell-structured gold nanoparticles are prone to aggregation at relatively high temperatures, and have poor stability and solubility

Method used

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  • Gold nanoparticle with core-shell structure and preparation method thereof
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  • Gold nanoparticle with core-shell structure and preparation method thereof

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preparation example Construction

[0026] The invention provides a method for preparing gold nanoparticles with a core-shell structure, comprising the following steps: A) poly(ethylene glycol-block-N-isopropylacrylamide) copolymer with a dithioester group at the end (PEG-b-PNIPAM) undergoes an aminolysis reaction with an aminolysis reagent to obtain a monomercapto-terminated poly(ethylene glycol-block-N-isopropylacrylamide) copolymer (PEG-b-PNIPAM-SH); B) Carrying out ligand exchange reaction between the poly(ethylene glycol-block-N-isopropylacrylamide) copolymer terminated by monomercapto and gold nanoparticles with sodium citrate as a ligand to obtain a core-shell structure Gold Nanoparticles.

[0027] Wherein, the PEG-b-PNIPAM is preferably prepared according to the reversible addition-fragmentation chain transfer (RAFT) method:

[0028] S1) Add monomethyl-terminated polyethylene glycol (mPEG-OH) and dry toluene solution into a container, under nitrogen protection, heat until mPEG-OH is completely dissolved...

Embodiment 1

[0041] 1.1 Synthesis of dithiobenzoic acid (DTBA)

[0042] Add 22.5g of 30% sodium methoxide solution, 4g of dry sulfur powder in a 250mL three-necked round bottom flask equipped with a stirring bar, a constant pressure dropping funnel and a spherical condenser, and slowly add 7.95 g benzyl, react at room temperature for 30 minutes after completion, then raise the temperature to 70°C and react overnight. After cooling in an ice-water bath, the insoluble matter was filtered off, and the solvent was removed under reduced pressure. The residue was re-dissolved in water, acidified by adding ether and 1.0mol / L hydrochloric acid to convert it into DTBA. Repeated extraction three times with iced sodium hydroxide solution and hydrochloric acid / ether solution, and finally obtained 6.6 g of pure red oily liquid as DTBA, with a yield of about 60%.

[0043] 1.2 Addition reaction of mPEG-OH with MAh

[0044] Add 8.0g mPEG-OH and 30mL dry toluene solution into a 100mL round bottom flask,...

Embodiment 2

[0076] Prepare each intermediate and final product in the same manner as in Example 1, only block copolymer PEG-b-PNIPAM is synthesized as follows:

[0077] Add 1.0 mg of azobisisobutyronitrile, 0.80 g of NIPAM, 0.20 g of the mPEG-CAT obtained in 1.4 and 5.5 mL of dry acetonitrile solution into a polymerization tube equipped with a stirring bar, and freeze-thaw the reaction mixture three times. Gas process, seal the tube under vacuum, and react at 60°C for 24h. The obtained product was precipitated three times with ether, and dried in vacuum at 50° C. for two days to obtain a block copolymer PEG-b-PNIPAM with a monomer conversion rate of about 30%.

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Abstract

The invention provides a gold nanoparticle with a core-shell structure and a preparation method thereof. The method comprises the following steps of: directly performing aminolysis on a dithioester at the tail end of a poly(glycol-segmented-N-isopropylacrylamide) copolymer of which the tail end is provided with a dithioester group to obtain a monothiol-terminated poly (glycol-segmented-N-isopropylacrylamide) copolymer; and performing ligand interchange reaction on the monothiol-terminated poly (glycol-segmented-N-isopropylacrylamide) copolymer and the gold nanoparticle with sodium citrate as a ligand, and grafting a segmented copolymer onto the surface of the gold nanoparticle to obtain the gold nanoparticle with the core-shell structure, wherein the shell of the gold nanoparticle is poly(glycol-segmented-N-isopropylacrylamide) copolymer (PEG-B-PNIPAM). Compared with the prior art, the outer layer of the block polymer has high solubility, so the formed gold nanoparticle with the core-shell structure also has high solubility. Due to the block PEG on the outer layer, the stability of the gold nanoparticle with the core-shell structure is also improved, and the aggregation among nanoparticles is inhibited.

Description

technical field [0001] The invention belongs to the technical field of nanomaterials, and in particular relates to a gold nanoparticle with a core-shell structure and a preparation method thereof. Background technique [0002] Core-shell materials generally consist of a central core and an outer shell. Through the core-shell composite method, on the one hand, the originally unstable or less stable core can be stabilized, and on the other hand, functions and properties that the core and shell materials do not have can be obtained, or new forms of substance can be obtained. [0003] In recent years, gold nanoparticles with core-shell structure have attracted extensive attention due to their potential applications in optoelectronics, biomedicine, and smart sensing. Gold nanoparticles with core-shell structure are divided into gold nanoparticles protected by a single layer of organic small molecules and gold nanoparticles protected by polymers. Compared with the former, gold na...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L53/00C08K3/08C08F293/00C08F2/38C08F8/00
Inventor 王大鹏姬相玲杨木泉董志鑫潘艳雄杨贺然
Owner CHANGZHOU INST OF ENERGY STORAGE MATERIALS &DEVICES