Effects of surfactants and alignment on the physical properties of single-walled carbon nanotube buckypaper

Park, Jin Gyu; Smithyman, Jesse; Lin, Chih-Yen; Cooke, Adam; Kismarahardja, Ade; Shu, Li; Liang, Richard; Brooks, J. S.; Zhang, Chuck; Wang, Ben

doi:10.1063/1.3255901

Cited by 89 publications

(64 citation statements)

References 42 publications

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“…6a) revealed a highly porous surface structure, and similar overall morphology to that observed in previous work. 30 It is clear from this figure that the membrane possesses a large number of irregularly sized pores, with image analysis revealing an average surface pore diameter of 23 AE 7 nm (Table 3). This agrees well with previous studies which showed that the surface pore sizes of buckypapers containing SWNTs vary between 10 and 100 nm in diameter.…”

Section: Surface Morphologymentioning

confidence: 99%

Synthesis, properties and water permeability of SWNT buckypapers

et al. 2012

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The ability of macrocyclic ligands to facilitate formation of dispersions of single-walled carbon nanotubes (SWNTs) was investigated using a combination of absorption spectrophotometry and optical microscopy. Vacuum filtration of aqueous dispersions containing SWNTs and various macrocyclic ligands (derivatised porphyrin, phthalocyanine, cyclodextrin and calixarene) afforded self-supporting membranes known as buckypapers. Microanalytical data and energy dispersive X-ray spectra were obtained for these buckypapers and provided evidence for retention of the macrocyclic ligands within the structure of the membranes. The electrical conductivities of the membranes varied between 30 ± 20 and 220 ± 60 S cm−1, while contact angle analysis revealed they all possessed hydrophilic surfaces. The mechanical properties of buckypapers prepared using macrocyclic ligands as dispersants were shown to be comparable to that of a benchmark material prepared using the surfactant Triton X-100 (Trix). Incorporation of the macrocyclic ligands into SWNT buckypapers was found to increase their permeability up to ten-fold compared to buckypapers prepared using Trix. No correlation was observed between the water permeability of the membranes and the average size of either their surface or internal pores. However, the water permeability of the membranes was found to be inversely dependent on their surface area. The ability of macrocyclic ligands to facilitate formation of dispersions of single-walled carbon nanotubes (SWNTs) was investigated using a combination of absorption spectrophotometry and optical microscopy. Vacuum filtration of aqueous dispersions containing SWNTs and various macrocyclic ligands (derivatised porphyrin, phthalocyanine, cyclodextrin and calixarene) afforded selfsupporting membranes known as buckypapers. Microanalytical data and energy dispersive X-ray spectra were obtained for these buckypapers and provided evidence for retention of the macrocyclic ligands within the structure of the membranes. The electrical conductivities of the membranes varied between 30 AE 20 and 220 AE 60 S cm À1

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Section: Surface Morphologymentioning

confidence: 99%

Synthesis, properties and water permeability of SWNT buckypapers

et al. 2012

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“…Different approaches to strengthen the CNT porous sheets, including electron irradiation [23], chemical treatment [24], polymer intercalation [25], and graphitization [26], have been theoretically and experimentally investigated, with some promising results. Park et al [27] fabricated PSNs based on SWNTs with improved mechanical properties and electrical conductivity. Li and Kruger [28] proposed that CNT PSNs with different mechanical properties and pore size can be designed through proper choice of ffiffiffiffiffiffiffiffiffi ffi EI=c p values, where EI and c denote the bending stiffness and binding energy of CNT, respectively.…”

Section: Introductionmentioning

confidence: 99%

Structure and properties of multi-walled carbon nanotube porous sheets with enhanced elongation

et al. 2012

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In this article, multi-walled carbon nanotubes (MWNTs)/dodecyl benzene sulfonic acid (DBSA) porous sheet networks (PSNs) of enhanced extensibility were developed and characterized. The MWNT/DBSA networks possess failure strains of 8-12 %, markedly higher than the literature reported values of 0.5-4 %. The networks were prepared through micro-filtration of highly dispersed MWNT in DBSA aqueous solutions. The DBSA molecule has two functions: In the dispersion stage, DBSA functions as a dispersant leading to the establishment of stable individually dispersed MWNT, and in the MWNT porous sheet, the presence of DBSA within the nanotubes' network creates a lubrication-like effect, enhancing the networks' extensibility. In fact, it was found that DBSA is assembled in two modes within the nanotubes' network: a fraction which is strongly adsorbed onto the CNT surface, and another fraction entrapped within the network as a DBSA/water solution. It should be noted that the composition of these systems is stable under ambient room temperature conditions. Comparison of MWNT networks prepared from the MWNT/DBSA dispersions and from the same but coagulated before filtration has shown superiority of the non-coagulated systems in relation to structure and mechanical properties. The prepared MWNT/DBSA PSNs of enhanced extensibility were developed without any modification by polymers, and they are characterized by high electrical conductivity and nano-porosity.

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“…However, the T 0 parameter in the VRH model does not directly relate to the junction resistance, but depends on the density and localization of the electronic states. Some previous studies show a possible correlation between the relative size of T 0 and the film resistance [10][11][12], where larger resistances imply greater localization. In this paper, we study conduction mechanisms in a series of thin networks with a sequence of resistances and identify an additional activation conduction mechanism that we ascribe to semiconducting nanotube segments in highly conducting paths.…”

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confidence: 96%

Charge transport in surfactant‐free single walled carbon nanotube networks

Ravi

Kaiser

Bumby³

2013

Physica Status Solidi (b)

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Conduction in thin random networks of single‐walled carbon nanotubes (SWNTs) is typically dominated by metallic SWNT segments and limited by variable‐range hopping (VRH) in disordered junction regions. However, in our surfactant‐free networks, we show that in parallel with VRH there is another mode of conduction involving both semiconducting and metallic SWNTs. This second process showing activated behavior makes a substantial contribution to conductance at higher temperatures, with similar activation energies in different samples despite a large variation in overall magnitude of the conductivity. From the magnitude of the activation energy (0.160.05\,eV), we ascribe this additional term to activation across Schottky barriers between metallic and semiconducting SWNTs in conducting paths involving a small number of semiconducting SWNTs. The Mott parameters for VRH are also independent of the overall conductivity, indicating that the local structure of intertube contacts between metallic SWNTs in the most conductive paths is also similar in samples of different overall conductivity.

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Effects of surfactants and alignment on the physical properties of single-walled carbon nanotube buckypaper

Cited by 89 publications

References 42 publications

Synthesis, properties and water permeability of SWNT buckypapers

Synthesis, properties and water permeability of SWNT buckypapers

Structure and properties of multi-walled carbon nanotube porous sheets with enhanced elongation

Charge transport in surfactant‐free single walled carbon nanotube networks

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