Tailoring the surface morphology of carbon nanotube forests by plasma etching: A parametric study

Seo, Seungju; Kim, Sanha; Yamamoto, Shun; Cui, Kehang; Kodama, Takashi; Shiomi, Junichiro; Inoue, Taiki; Chiashi, Shohei; Maruyama, Shigeo; Hart, A. John

doi:10.1016/j.carbon.2021.04.066

Cited by 16 publications

(12 citation statements)

References 55 publications

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“…Notably, in order to tailor the antibacterial capacity of these carbon nanostructures, it is crucial to shape the spatial arrangement up to the sub-micrometric domain. In this regard, while CNTs dispersed in liquid media are difficult to control, vertically aligned carbon nanotubes (VA-CNTs), also known as CNT forests, can offer a tunable antibacterial platform thanks to the possibility to direct the tubes’ alignment, diameter, length, and density via both in and ex situ processes [ 39 , 40 ]. The catalytic chemical vapor deposition (CVD) technique is the most widely exploited process for the synthesis of VA-CNTs [ 41 ].…”

Section: Introductionmentioning

confidence: 99%

“…At the onset of CVD growth, straight and curved tubes are formed at the same macroscopic rate due to the interaction between fast- and slow-grown CNTs, thus leading to the self-arrangement of tubes in an entangled and randomly oriented configuration, known as the “crust layer” [ 44 ]. After the formation of such an intricate network of CNTs, the tubes continue to grow perpendicularly to the underlying substrate due to van der Waals interactions between them [ 45 , 46 ], displacing the crust on top of the forest [ 40 ].…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively, as in the case of FIB, a high level of precision in modifying the tube morphology can be achieved, but at the same time, undesired by-products and carbon redeposition are formed, and, in addition, long manufacturing times are required [ 50 ]. Conversely, plasma treatments have largely demonstrated to be capable of tailoring the morphology of CNTs in a controlled and time-efficient manner [ 40 , 51 , 52 ].…”

Section: Introductionmentioning

confidence: 99%

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Plasma-Etched Vertically Aligned CNTs with Enhanced Antibacterial Power

et al. 2023

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The emergence of multidrug-resistant bacteria represents a growing threat to public health, and it calls for the development of alternative antibacterial approaches not based on antibiotics. Here, we propose vertically aligned carbon nanotubes (VA-CNTs), with a properly designed nanomorphology, as effective platforms to kill bacteria. We show, via a combination of microscopic and spectroscopic techniques, the ability to tailor the topography of VA-CNTs, in a controlled and time-efficient manner, by means of plasma etching processes. Three different varieties of VA-CNTs were investigated, in terms of antibacterial and antibiofilm activity, against Pseudomonas aeruginosa and Staphylococcus aureus: one as-grown variety and two varieties receiving different etching treatments. The highest reduction in cell viability (100% and 97% for P. aeruginosa and S. aureus, respectively) was observed for the VA-CNTs modified using Ar and O2 as an etching gas, thus identifying the best configuration for a VA-CNT-based surface to inactivate both planktonic and biofilm infections. Additionally, we demonstrate that the powerful antibacterial activity of VA-CNTs is determined by a synergistic effect of both mechanical injuries and ROS production. The possibility of achieving a bacterial inactivation close to 100%, by modulating the physico-chemical features of VA-CNTs, opens up new opportunities for the design of self-cleaning surfaces, preventing the formation of microbial colonies.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Plasma-Etched Vertically Aligned CNTs with Enhanced Antibacterial Power

et al. 2023

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“…[29] CNTs can be grown in an oriented and aligned array, but an etching process was needed to release the ends of the CNTs bounded by the metal catalyst. [30,31] The template direct synthesis of CNTs was improved from CVD. A nanoporous anodic alumina membrane (NAAM) was introduced to control the direction, outer diameter, and length of CNTs.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a Free‐Standing MWCNT Electrode by Electric Field Force for an Ultra‐Sensitive MicroRNA‐21 Nano‐Genosensor

Wang

et al. 2022

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Abnormal expression of microRNA‐21 (miR‐21) is considered to be closely associated with the pathogenesis of colorectal cancer. However, great challenges do exist for the development of ultra‐sensitive biosensors to detect the abnormal expression of miR‐21 due to the low concentration in serum (fm level) at the early stage of colorectal cancer. Therefore, electric field force is used to rotate and rearrange random multi‐walled carbon nanotubes (MWCNTs) at the microscale to improve the active sites of the electrode in this study. The free‐standing MWCNTs are densely and high‐orderly embedded into the bare electrode along the direction of the electric field. Compared to the bare electrode, the peak‐current response of the free‐standing MWCNT electrode improves by 150 times in cyclic voltammetric measurement. A nano‐genosensor based on the free‐standing MWCNT electrode is developed for measuring miR‐21. The nano‐genosensor for miR‐21 shows an ultra‐high sensitivity of 48.24 µA µm−1, a wide linear range from 0.01 × 10−15 to 100 × 10−12 m, and a low detection limit of 1.2 × 10−18 m. The present nano‐genosensor shows superior performance for miR‐21 in human serum samples and demonstrates a potential application for the diagnosis of early stage colorectal cancer.

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“…The top surfaces of both samples are shaded light blue for clarity. Before ALD, the top crust of the CNT array is etched by plasma cleaning, 32 so that the tips of CNTs are fully exposed (Figure 1g). After ALD, Ru nanoparticles are formed at the CNT tips on the top surface of the Ru-CNT nanocomposite (Figure 1h and Supporting Information Figure S1).…”

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confidence: 99%

Multiscale Plasmonic Refractory Nanocomposites for High-Temperature Solar Photothermal Conversion

et al. 2022

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Development of a refractory selective solar absorber (RSSA) is the key to unlock high-temperature solar thermal and thermochemical conversion. The fundamental challenge of RSSA is the lack of design and fabrication guidelines to simultaneously achieve omnidirectional, broadband solar absorption and sharp spectral selectivity at the desired cutoff wavelength. Here, we realize a ruthenium–carbon nanotube (Ru-CNT) nanocomposite RSSA with multiscale nanoparticle-on-nanocavity plasmonic modes. Ru conformally coated on the sidewalls of CNTs enables a spoof surface plasmon polariton mode for spectra selectivity; Ru nanoparticles formed at the tips of CNTs enable a localized surface plasmon resonance mode and plasmon hybridization for omnidirectional broadband solar absorption. The fabricated Ru-CNT RSSA has a total solar absorption (TSA) of 96.1% with sharp spectral cutoff at 2.21 μm. The TSA is maintained at over 90% for an incident angle of 56°. Our findings therefore guide full-spectrum optical and thermal control from visible to the far-infrared.

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Tailoring the surface morphology of carbon nanotube forests by plasma etching: A parametric study

Cited by 16 publications

References 55 publications

Plasma-Etched Vertically Aligned CNTs with Enhanced Antibacterial Power

Plasma-Etched Vertically Aligned CNTs with Enhanced Antibacterial Power

Fabrication of a Free‐Standing MWCNT Electrode by Electric Field Force for an Ultra‐Sensitive MicroRNA‐21 Nano‐Genosensor

Multiscale Plasmonic Refractory Nanocomposites for High-Temperature Solar Photothermal Conversion

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