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A facile synthesis of polypyrrole/carbon nanotube composites with ultrathin, uniform and thickness-tunable polypyrrole shells.

Zhang B, Xu Y, Zheng Y, Dai L, Zhang M, Yang J, Chen Y, Chen X, Zhou J - Nanoscale Res Lett (2011)

Bottom Line: An improved approach to assemble ultrathin and thickness-tunable polypyrrole (PPy) films onto multiwall carbon nanotubes (MWCNTs) has been investigated.The coated PPy films can be easily tuned by adding ethanol and adjusting a mass ratio of pyrrole to MWCNTs.Moreover, the thickness of PPy significantly influences the electronic conductivity and capacitive behavior of the PPy/MWCNT composites.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Lab Polymer Composite & Funct Mat, Key Lab Designed Synth & Applicat Polymer Mat, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275, China. lzdai@xmu.edu.cn.

ABSTRACT
An improved approach to assemble ultrathin and thickness-tunable polypyrrole (PPy) films onto multiwall carbon nanotubes (MWCNTs) has been investigated. A facile procedure is demonstrated for controlling the morphology and thickness of PPy film by adding ethanol in the reaction system and a possible mechanism of the coating formation process is proposed. The coated PPy films can be easily tuned by adding ethanol and adjusting a mass ratio of pyrrole to MWCNTs. Moreover, the thickness of PPy significantly influences the electronic conductivity and capacitive behavior of the PPy/MWCNT composites. The method may provide a facile strategy for tailoring the polymer coating on carbon nanotubes (CNTs) for carbon-based device applications.

No MeSH data available.


TGA analysis of PPy, MWNT, and PPy/MWCNT composites: (a) MWCNT-COOH; (b) PPy/MWCNT-1 composite prepared by adding ethanol; (c) PPy/MWCNT-2 composite prepared without ethanol; (d) pure PPy. The insets are the TEM images PPy/MWCNT-1 and PPy/MWCNT-2, respectively.
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Figure 3: TGA analysis of PPy, MWNT, and PPy/MWCNT composites: (a) MWCNT-COOH; (b) PPy/MWCNT-1 composite prepared by adding ethanol; (c) PPy/MWCNT-2 composite prepared without ethanol; (d) pure PPy. The insets are the TEM images PPy/MWCNT-1 and PPy/MWCNT-2, respectively.

Mentions: Changes in intrinsic polymer properties brought about by the addition of MWCNTs are indicative of nanotube-matrix interactions [22]. Improved thermal stability in polymer/CNTs composites systems relative to the polymers have been predicted by classical molecular dynamic simulations [27]. Therefore, thermogravimetric analyzer measurements of the PPy/MWCNT composites were carried out, and the results are shown in Figure. 3. MWCNTs are comparatively stable and showing no dramatic decomposition, with a 15% mass loss being observed [21]. However, for pure PPy, two steps rapid mass loss occurred at around 190°C and 320°C are depicted by two vertical lines in curve d, which is attributed to the thermal oxidative decomposition of PPy chains, and only 20% mass remained for pure PPy at 900°C [28]. For investigating the thermal oxidative decomposition of PPy/MWCNT composites with different shell thickness, two PPy/MWCNT composites were prepared at the same mass ratio of pyrrole to MWCNTs (6:4) with (PPy-CNT-1, curve b) and without (PPy-CNT-2, curve c) the addition of ethanol in the reaction solution. Two steps rapid mass loss are also observed as indicated by the vertical lines in curves b and c, respectively [29] These two composites show more delay decomposition compared to pure PPy. The improved thermal stability of PPy/MWCNT composites indicates that there should exist interfacial interaction between CNTs with polymer shell[21]. Furthermore, it is worth noting that the temperatures of two steps rapid mass loss for PPy-CNT-1 composite (curve b) are increased from 210°C and 360°C to 280°C and 410°C, respectively, compared with the PPy-CNT-2 composite (curve c). In contrast, the coated-polymer for the PPy-CNT-2 composite is 20 wt.% higher than the former. The reason for this is given by the TEM images of the two PPy/MWCNT composites (shown in the inset of Figure 3). Both of the two images reveals a coaxial structure of the resulted PPy/MWCNT composites in which the MWCNT is encapsulated by a uniform shell of PPy. However, the surface of PPy-CNT-1 composite appears to be smooth and uniform, and there are no agglomerations or irregular nanoparticles of polymer after a sonicated dispersion. Clearly, a lot of irregular PPy particles and some agglomerations are found when PPy/MWCNT composite is fabricated without ethanol. The granular PPy products absorbed on the carbon nanotubes surface during the ragid self polymerization reaction of PPy exhibit the weak adherent ability to the carbon nanotubes. Therefore, ethanol plays an important role in restraining the polymerization reaction, controlling the self polymerization of pyrrole monomers, enhancing the interfacial bonding of polymer/carbon nanotubes and controlling the morphology of polymer film on MWCNTs surface.


A facile synthesis of polypyrrole/carbon nanotube composites with ultrathin, uniform and thickness-tunable polypyrrole shells.

Zhang B, Xu Y, Zheng Y, Dai L, Zhang M, Yang J, Chen Y, Chen X, Zhou J - Nanoscale Res Lett (2011)

TGA analysis of PPy, MWNT, and PPy/MWCNT composites: (a) MWCNT-COOH; (b) PPy/MWCNT-1 composite prepared by adding ethanol; (c) PPy/MWCNT-2 composite prepared without ethanol; (d) pure PPy. The insets are the TEM images PPy/MWCNT-1 and PPy/MWCNT-2, respectively.
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Figure 3: TGA analysis of PPy, MWNT, and PPy/MWCNT composites: (a) MWCNT-COOH; (b) PPy/MWCNT-1 composite prepared by adding ethanol; (c) PPy/MWCNT-2 composite prepared without ethanol; (d) pure PPy. The insets are the TEM images PPy/MWCNT-1 and PPy/MWCNT-2, respectively.
Mentions: Changes in intrinsic polymer properties brought about by the addition of MWCNTs are indicative of nanotube-matrix interactions [22]. Improved thermal stability in polymer/CNTs composites systems relative to the polymers have been predicted by classical molecular dynamic simulations [27]. Therefore, thermogravimetric analyzer measurements of the PPy/MWCNT composites were carried out, and the results are shown in Figure. 3. MWCNTs are comparatively stable and showing no dramatic decomposition, with a 15% mass loss being observed [21]. However, for pure PPy, two steps rapid mass loss occurred at around 190°C and 320°C are depicted by two vertical lines in curve d, which is attributed to the thermal oxidative decomposition of PPy chains, and only 20% mass remained for pure PPy at 900°C [28]. For investigating the thermal oxidative decomposition of PPy/MWCNT composites with different shell thickness, two PPy/MWCNT composites were prepared at the same mass ratio of pyrrole to MWCNTs (6:4) with (PPy-CNT-1, curve b) and without (PPy-CNT-2, curve c) the addition of ethanol in the reaction solution. Two steps rapid mass loss are also observed as indicated by the vertical lines in curves b and c, respectively [29] These two composites show more delay decomposition compared to pure PPy. The improved thermal stability of PPy/MWCNT composites indicates that there should exist interfacial interaction between CNTs with polymer shell[21]. Furthermore, it is worth noting that the temperatures of two steps rapid mass loss for PPy-CNT-1 composite (curve b) are increased from 210°C and 360°C to 280°C and 410°C, respectively, compared with the PPy-CNT-2 composite (curve c). In contrast, the coated-polymer for the PPy-CNT-2 composite is 20 wt.% higher than the former. The reason for this is given by the TEM images of the two PPy/MWCNT composites (shown in the inset of Figure 3). Both of the two images reveals a coaxial structure of the resulted PPy/MWCNT composites in which the MWCNT is encapsulated by a uniform shell of PPy. However, the surface of PPy-CNT-1 composite appears to be smooth and uniform, and there are no agglomerations or irregular nanoparticles of polymer after a sonicated dispersion. Clearly, a lot of irregular PPy particles and some agglomerations are found when PPy/MWCNT composite is fabricated without ethanol. The granular PPy products absorbed on the carbon nanotubes surface during the ragid self polymerization reaction of PPy exhibit the weak adherent ability to the carbon nanotubes. Therefore, ethanol plays an important role in restraining the polymerization reaction, controlling the self polymerization of pyrrole monomers, enhancing the interfacial bonding of polymer/carbon nanotubes and controlling the morphology of polymer film on MWCNTs surface.

Bottom Line: An improved approach to assemble ultrathin and thickness-tunable polypyrrole (PPy) films onto multiwall carbon nanotubes (MWCNTs) has been investigated.The coated PPy films can be easily tuned by adding ethanol and adjusting a mass ratio of pyrrole to MWCNTs.Moreover, the thickness of PPy significantly influences the electronic conductivity and capacitive behavior of the PPy/MWCNT composites.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Lab Polymer Composite & Funct Mat, Key Lab Designed Synth & Applicat Polymer Mat, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275, China. lzdai@xmu.edu.cn.

ABSTRACT
An improved approach to assemble ultrathin and thickness-tunable polypyrrole (PPy) films onto multiwall carbon nanotubes (MWCNTs) has been investigated. A facile procedure is demonstrated for controlling the morphology and thickness of PPy film by adding ethanol in the reaction system and a possible mechanism of the coating formation process is proposed. The coated PPy films can be easily tuned by adding ethanol and adjusting a mass ratio of pyrrole to MWCNTs. Moreover, the thickness of PPy significantly influences the electronic conductivity and capacitive behavior of the PPy/MWCNT composites. The method may provide a facile strategy for tailoring the polymer coating on carbon nanotubes (CNTs) for carbon-based device applications.

No MeSH data available.