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Non-covalent polymer wrapping of carbon nanotubes and the role of wrapped polymers as functional dispersants

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ABSTRACT

Carbon nanotubes (CNTs) have been recognized as a promising material in a wide range of applications from biotechnology to energy-related devices. However, the poor solubility in aqueous and organic solvents hindered the applications of CNTs. As studies have progressed, the methodology for CNT dispersion was established. In this methodology, the key issue is to covalently or non-covalently functionalize the surfaces of the CNTs with a dispersant. Among the various types of dispersions, polymer wrapping through non-covalent interactions is attractive in terms of the stability and homogeneity of the functionalization. Recently, by taking advantage of their stability, the wrapped-polymers have been utilized to support and/or reinforce the unique functionality of the CNTs, leading to the development of high-performance devices. In this review, various polymer wrapping approaches, together with the applications of the polymer-wrapped CNTs, are summarized.

No MeSH data available.


(a) Examples of the chemical structures of the block copolymer-based dispersants. (b) TEM bright-field image of SWCNTs dispersed with PS-P4VP. Micelles are located between two nanotubes, by indicated arrows, implying a possible de-bundling of SWCNTs by micelles. (c), (d) Schematic model of the nanostructure of SWCNTs and block copolymer. PS and P4VP are selectively adsorbed on the surface of nanotubes in (c) toluene and (d) ethanol, respectively. Parts (b)–(d) reproduced with permission from H-i Shin et al 2005 Macromol. Rapid Commun.26 1451. Copyright 2005 John Wiley and Sons.
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Figure 15: (a) Examples of the chemical structures of the block copolymer-based dispersants. (b) TEM bright-field image of SWCNTs dispersed with PS-P4VP. Micelles are located between two nanotubes, by indicated arrows, implying a possible de-bundling of SWCNTs by micelles. (c), (d) Schematic model of the nanostructure of SWCNTs and block copolymer. PS and P4VP are selectively adsorbed on the surface of nanotubes in (c) toluene and (d) ethanol, respectively. Parts (b)–(d) reproduced with permission from H-i Shin et al 2005 Macromol. Rapid Commun.26 1451. Copyright 2005 John Wiley and Sons.

Mentions: It is also believed that amphiphilicity of the polymers may contribute to the dispersion of the CNTs through a micelle-encapsulation mechanism. Kang and Taton found that the micelle formation in a DMF solution of polystyrene-b-poly(acrylic acid) (PS-PAA, figure 15) [155] induced by water addition enabled the dispersion of SWCNTs. A wide range of block copolymers were reported to disperse CNTs through the micelle encapsulation mechanism in which either polystyrene (PS) [155–163] or polyethylene oxide (PEO) [158, 159, 164, 165] units were introduced as the blocks in most of the cases (figure 15(a)). Shin et al found by TEM analysis that in the case of a PS-b-poly(4-vinyl pyridine) (P4VP) block copolymer as the dispersant, PS domains were exposed to the outer surfaces in a non-polar toluene solution, while a P4VP domain was located to an outer surface in the polar ethanol solution (figures 15(b)–(d)) [161]. This observation provided a strong indication of the mechanism of the micelle encapsulation of CNTs using the block copolymers.


Non-covalent polymer wrapping of carbon nanotubes and the role of wrapped polymers as functional dispersants
(a) Examples of the chemical structures of the block copolymer-based dispersants. (b) TEM bright-field image of SWCNTs dispersed with PS-P4VP. Micelles are located between two nanotubes, by indicated arrows, implying a possible de-bundling of SWCNTs by micelles. (c), (d) Schematic model of the nanostructure of SWCNTs and block copolymer. PS and P4VP are selectively adsorbed on the surface of nanotubes in (c) toluene and (d) ethanol, respectively. Parts (b)–(d) reproduced with permission from H-i Shin et al 2005 Macromol. Rapid Commun.26 1451. Copyright 2005 John Wiley and Sons.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 15: (a) Examples of the chemical structures of the block copolymer-based dispersants. (b) TEM bright-field image of SWCNTs dispersed with PS-P4VP. Micelles are located between two nanotubes, by indicated arrows, implying a possible de-bundling of SWCNTs by micelles. (c), (d) Schematic model of the nanostructure of SWCNTs and block copolymer. PS and P4VP are selectively adsorbed on the surface of nanotubes in (c) toluene and (d) ethanol, respectively. Parts (b)–(d) reproduced with permission from H-i Shin et al 2005 Macromol. Rapid Commun.26 1451. Copyright 2005 John Wiley and Sons.
Mentions: It is also believed that amphiphilicity of the polymers may contribute to the dispersion of the CNTs through a micelle-encapsulation mechanism. Kang and Taton found that the micelle formation in a DMF solution of polystyrene-b-poly(acrylic acid) (PS-PAA, figure 15) [155] induced by water addition enabled the dispersion of SWCNTs. A wide range of block copolymers were reported to disperse CNTs through the micelle encapsulation mechanism in which either polystyrene (PS) [155–163] or polyethylene oxide (PEO) [158, 159, 164, 165] units were introduced as the blocks in most of the cases (figure 15(a)). Shin et al found by TEM analysis that in the case of a PS-b-poly(4-vinyl pyridine) (P4VP) block copolymer as the dispersant, PS domains were exposed to the outer surfaces in a non-polar toluene solution, while a P4VP domain was located to an outer surface in the polar ethanol solution (figures 15(b)–(d)) [161]. This observation provided a strong indication of the mechanism of the micelle encapsulation of CNTs using the block copolymers.

View Article: PubMed Central - PubMed

ABSTRACT

Carbon nanotubes (CNTs) have been recognized as a promising material in a wide range of applications from biotechnology to energy-related devices. However, the poor solubility in aqueous and organic solvents hindered the applications of CNTs. As studies have progressed, the methodology for CNT dispersion was established. In this methodology, the key issue is to covalently or non-covalently functionalize the surfaces of the CNTs with a dispersant. Among the various types of dispersions, polymer wrapping through non-covalent interactions is attractive in terms of the stability and homogeneity of the functionalization. Recently, by taking advantage of their stability, the wrapped-polymers have been utilized to support and/or reinforce the unique functionality of the CNTs, leading to the development of high-performance devices. In this review, various polymer wrapping approaches, together with the applications of the polymer-wrapped CNTs, are summarized.

No MeSH data available.