Summary

Usando Polystyrene-<em> Bloco</em> -poli (Ácido acrílico) -Revestido metal Nanopartículas como monómeros para a sua homo- e co-polimerização

Published: July 09, 2015
doi:

Summary

We report protocols for “polymerizing” various types of polymer-encapsulated metal nanoparticles into long chains of “homo-“ and “co-polymers”.

Abstract

We present a template-free method for “polymerizing” nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block “copolymers” of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Introduction

Despite great advances in the synthesis of nanoparticles over the past two decades, their orderly assembly remains a great challenge. Our synthetic capabilities in putting the basic building blocks together are of critical importance for the exploration and exploitation of their synergistic effects and collective properties. Thus, developing new reaction pathways and exploring the underlying mechanisms are the stepping stones towards the rational synthesis of complex nanodevices.

Among the rich structural variety of possible nanoparticle assemblies, one-dimensional (1D) chains have shown useful applications in nanoelectronics, optoelectronics, and biosensors.1-4 Typically, self-assembly of nanoparticles into chain-like structures requires magnetic or electric dipole interactions, anisotropic electrostatic repulsion, or external templates.5-11 For dipole-induced assembly, one needs nanoparticles with permanent dipoles, such as magnetic nanoparticles and semiconductor nanoparticles under special environments.12-15 For nanoparticles with no permanent dipole, it has been shown that the relatively weaker electrostatic repulsion at the ends of the nanoparticle chains can promote the selective attachment of nanoparticle thereon and thus, 1D chain growth.16,17 Because the nanoparticles can aggregate with each other and with the oligomers, the aggregation often follows the intrinsic step-growth mode, leading to short chain length and the lack of control over branching. Lastly, nanoparticles can be adsorbed onto 1D templates to form chains, but usually it is very difficult to achieve secure anchoring and avoid gaps among the nanoparticles.

With these existing methods, hetero-assembly or “co-polymerization” of nanoparticles is particularly difficult. A few pioneer works have demonstrated the “co-polymerization” of short nanoparticle chains exploiting magnetic dipole18 or electrostatic repulsion.19

Recently, we reported the homo- and co-polymerization of PSPAA-coated nanoparticles into chains.20,21 This new synthetic pathway involves facile colloidal synthesis and generic use of different types of nanoparticles. It affords ultralong chains without branching and allows ready control of their length and width (single-, double-, and triple-line chains). Most importantly, random- and co-polymers of nanoparticles can be synthesized with improved structural control. In this work, we provide video protocols for the related syntheses, intending to give a detailed demonstration and presentation.

Protocol

Atenção: Por favor, consulte todas as fichas de dados de segurança de materiais relevantes (FDSP). Alguns produtos químicos usados ​​nestas sínteses são corrosivo, tóxico e possivelmente carcinogéneo. Os nanomateriais podem ter riscos não reconhecidos, em comparação com os seus homólogos em massa. Utilize as práticas de segurança adequadas ao realizar reacção, incluindo o uso de coifa e equipamentos de proteção individual (óculos de segurança, luvas, jaleco, calça de corpo inteiro, sapatos fechados, etc.). …

Representative Results

Os monómeros de nanopartículas e as cadeias são caracterizados por MET. A Figura 1 mostra as imagens representativas de MET das PSPAA monómeros encapsulado, confirmando as morfologias e tamanhos (Figura 1). Como alguns monómeros tipicamente permanecem na amostra após a "polimerização", a amostra é geralmente purificado e concentrado antes de ser usado para a caracterização de TEM. A mancha foi introduzido durante a preparação das amostras TEM misturando a soluçã…

Discussion

Os detalhes mecanicistas de sínteses são relatados e discutidos nas publicações anteriores. 20,21 Aqui vamos nos concentrar nas lógicas das condições sintéticas. Para a polimerização de nanopartículas, prefere-se que as nanopartículas de tamanho uniforme são utilizados. Nós seguimos os procedimentos da literatura para obter as nanopartículas uniformes Au Au, 23, 24 nanobastões e nanofios Te 25 em geral., Melhor uniformidade de tamanho podem ser obtidos quando os estágios…

Divulgaciones

The authors have nothing to disclose.

Acknowledgements

The authors thank the NRF (CRP-4-2008-06), A*Star (SERC 112-120-2011) and MOE (RG14/13) Singapore for financial supports.

Materials

Gold(III) chloride trihydrate, ACS reagent, ≥49.0% Au basis
 
Sigma-Aldrich G4022 HAuCl4
Sodium citrate dihydrate, 99% Alfa Aesar A12274
Sodium borohydride, ≥99%
 
Sigma-Aldrich 71321, Fluka
Hexadecyltrimethylammonium bromide,≥98%  Sigma-Aldrich H5882 CTAB
Silver Nitrate, 99.9999% trace metals basis Sigma-Aldrich 204390
L-ascorbic acid,BioXtra, ≥99.0%, crystalline
 
Sigma-Aldrich A5960
Tellurium dioxide,≥99%  Sigma-Aldrich 243450
Hydrazine monohydrate, 64-65 %, reagent grade, 98%  Sigma-Aldrich 207942
Poly(styrene-b-acrylic acid)(PS154-PAA49) Polymer Source P4673A-SAA PS16000-PAA3500
Poly(styrene-b-acrylic acid)(PS144-PAA28) Polymer Source P4002-SAA PS15000-PAA1600
2-Naphthalenethiol,
 ≥99.0% (GC) 
Sigma-Aldrich 88910, Fluka
Sodium dodecyl sulfate, 99% Alfa Aesar A11183
single wall carbon nanotubes, 99%  ultra-pure NanoIntegris PC10344a
Sodium hydroxide Sinopharm S1900136
1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (sodium salt)  Avanti polar lipids 870160P PSH
N,N-dimethylformamide Merck SA4s640012
Ethanol, absolute Fischer E/0650DF/17
Hydrochloric acid, 37% Honey well 10189005 Dilute to 1M before use 

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Citar este artículo
Wang, Y., Song, X., Wang, H., Chen, H. Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization. J. Vis. Exp. (101), e52954, doi:10.3791/52954 (2015).

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