Liquid-crystalline behaviors of single-walled carbon nanotube aqueous dispersions with different nanotube aspect ratios and surfactants

Kojima, Keiko; Jintoku, Hirokuni; Kuwahara, Yasuto; Aizawa, Miho; Yamamoto, Takahiro; Muroga, Shun; Kobashi, Kazufumi; Okazaki, Toshiya

doi:10.35848/1882-0786/aca23c

Cited by 3 publications

(44 citation statements)

References 30 publications

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“…The transition concentrations from the isotropic phase to the biphasic state, and from the biphasic state to the nematic phase were inversely proportional to the aspect ratio ( L / D ) of the SWCNT, following the same trend as the Onsager theory [ 7 , 9 , 11 , 15 , 20 , 23 – 24 ]. By using dispersions with higher SWCNT aspect ratio, a film of SWCNTs with a higher order parameter was prepared by the bar-coating method [ 23 ]. Therefore, it is essential to prepare CNT LCs that contain rod-like CNTs with a high L / D to fabricate well-ordered CNT materials.…”

Section: Introductionmentioning

confidence: 61%

“…In addition, the shapes of the spindle-shaped nematic LC, or so-called tactoids, in the biphasic state were examined. The transition from homogeneous tactoids to bipolar tactoids occurred at a larger tactoid volume than that previously observed [ 23 ]. This can be ascribed to the higher L / D of the DWCNTs in this study.…”

Section: Introductionmentioning

confidence: 64%

“…The DWCNT powder was dispersed with a surfactant of sodium cholate (SC) in water by a two-step process [ 22 – 23 ] (see the Experimental section). The size distribution of the DWCNTs in the dispersion was estimated by DCS method ( Figure 1a ).…”

Section: Resultsmentioning

confidence: 99%

“…Besides, DCS analysis also identified a smaller peak at around 0.1 μm ( Figure 1a , inset). The signal can be attributed to DWCNT agglomerates that are 10 μm in size, taking into account the buoyancy resulting from particle porosity [ 22 – 23 27 – 28 ]. Indeed, the DWCNT agglomerates having corresponding size can be seen in the optical microscope image of the dispersion ( Figure 1b ).…”

Section: Resultsmentioning

confidence: 99%

“…In previous studies, we prepared surfactant-stabilized aqueous dispersions of SWCNT LC and evaluated their dispersion states using the differential centrifugal sedimentation (DCS) method [ 22 – 23 ]. The transition concentrations from the isotropic phase to the biphasic state, and from the biphasic state to the nematic phase were inversely proportional to the aspect ratio ( L / D ) of the SWCNT, following the same trend as the Onsager theory [ 7 , 9 , 11 , 15 , 20 , 23 – 24 ]. By using dispersions with higher SWCNT aspect ratio, a film of SWCNTs with a higher order parameter was prepared by the bar-coating method [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

Kojima,

Kosugi,

Jintoku

et al. 2024

Beilstein J. Org. Chem.

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We successfully prepared a surfactant-assisted carbon nanotube (CNT) liquid crystal (LC) dispersion with double-walled CNTs (DWCNTs) having a high aspect ratio (≈1378). Compared to dispersions of single-walled CNTs (SWCNTs) with lower aspect ratio, the transition concentrations from isotropic phase to biphasic state, and from biphasic state to nematic phase are lowered, which is consistent with the predictions of the Onsager theory. An aligned DWCNT film was prepared from the DWCNT dispersion by a simple bar-coating method. Regardless of the higher aspect ratio, the order parameter obtained from the film is comparable to that from SWCNTs with lower aspect ratios. This finding implies that precise control of the film formation process, including a proper selection of substrate and deposition/drying steps, is crucial to maximize the CNT-LC utilization.

show abstract

Section: Introductionmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

Kojima,

Kosugi,

Jintoku

et al. 2024

Beilstein J. Org. Chem.

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Wet-spinning of carbon nanotube fibers: dispersion, processing and properties

Yang,

Huang

et al. 2024

National Science Review

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Owing to the intrinsic excellent mechanical, electrical, and thermal properties of carbon nanotubes (CNTs), carbon nanotube fibers (CNTFs) have been expected to be promising candidates for the next-generation high-performance fibers. It has received considerable interest for cutting-edge applications, such as ultra-light electric wire, aerospace craft, military equipment, and space elevators. Wet-spinning is a broadly utilized commercial technique for high-performance fiber manufacturing. Thus, compared with array spinning from drawable CNTs vertical array and direct dry spinning from floating catalyst chemical vapor deposition (FCCVD), wet-spinning technique is considered as a promising strategy to realize the massive production of CNTFs. In this tutorial review, we initiate with a summative description of CNTFs wet-spinning process. Then, we discuss the high-concentration CNTs wet-spinning dope preparation strategies and corresponding non-covalent adsorption/charge transfer mechanisms. The filament solidification during the coagulation process is another critical procedure for determining the configuration and properties for derived CNTFs. Afterwards, the post-treatment, including continuous drafting and thermal annealing, to further optimize the CNTs orientation and compact configuration. At last, we also summarize the physical property-structure relationship to give the insights for further performance promotion to satisfy the prerequisite for detail application scenario. Insights into propelling high-performance CNTFs production from lab-scale to industry-scale are proposed, in anticipation of this novel fiber having its killer application and impacting our life in near future.

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Preparing liquid crystalline dispersion of high aspect ratio carbon nanotubes

Kojima,

Kosugi,

Jintoku

et al. 2023

Preprint

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We successfully prepare the surfactant-assisted carbon nanotube (CNT) liquid crystal (LC) dispersion with double-walled CNTs (DWCNTs) having a high aspect ratio (~1378). Compared to dispersions of lower aspect ratio CNTs, the transition concentrations from isotropic phase to biphasic state, and from biphasic state to nematic phase are lowered, which is consistent with the predictions of Onsager theory. An aligned CNT film was prepared from the DWCNT dispersion by a simple bar-coating method. Regardless of the higher aspect ratio, the order parameter obtained from the film is comparable to that from CNTs with lower aspect ratios. This finding implies that precise control of the film formation process, including a proper selection of substrate and deposition/drying steps, is crucial to maximize CNT-LC utilization.

show abstract

Liquid-crystalline behaviors of single-walled carbon nanotube aqueous dispersions with different nanotube aspect ratios and surfactants

Cited by 3 publications

References 30 publications

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

Wet-spinning of carbon nanotube fibers: dispersion, processing and properties

Preparing liquid crystalline dispersion of high aspect ratio carbon nanotubes

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