Summary

Verwendung Polystyrol-<em> Block</em> -Poly (Acrylsäure) beschichteten Metallnanopartikel als Monomere für ihre Homo- und Polymerisation

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

Achtung: Bitte beachten Sie alle relevanten Sicherheitsdatenblätter (MSDS). Einige Chemikalien in diesen Synthesen verwendet werden, sind ätzend, giftig und möglicherweise krebserregend. Nanomaterialien können unerkannte Gefahren haben im Vergleich zu ihren Groß Kollegen. Bitte verwenden Sie geeignete Sicherheitsmaßnahmen bei der Durchführung von Reaktion, einschließlich der Verwendung von Abzugshaube und persönliche Schutzausrüstungen (Schutzbrille, Handschuhe, Labormantel, in voller Länge Hosen, geschlossene Schuhe, etc.).<…

Representative Results

Die Nanopartikelmonomere und Ketten durch TEM. 1 zeigt die repräsentative TEM-Bilder der PSPAA eingekapselt Monomeren und bestätigt die Morphologien und Größen (Abbildung 1). Da einige Monomere in der Regel in der Probe nach der "Polymerisation" bleiben, wird die Probe in der Regel gereinigt und vor dem für die TEM-Charakterisierung konzentriert. Ein Fleck wurde während der Herstellung der TEM-Proben durch Mischen der Probenlösung mit 1% Ammoniummolybdat, um die Polymer…

Discussion

Die mechanistischen Details der Synthesen berichtet und in den früheren Veröffentlichungen diskutiert. 20,21 Hier konzentrieren wir uns auf die Grundprinzipien der Synthesebedingungen. Für die Polymerisation von Nanopartikeln ist es bevorzugt, dass Nanopartikel von einheitlicher Größe verwendet. Wir folgen der Literatur beschriebenen Verfahren, um die gleichmäßige Au-Nanopartikeln, 23 Au-Nanostäbchen, 24 und Te-Nanodrähte. 25 In der Regel bessere Gleichmäßigkeit Gr?…

Declarações

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 artigo
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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