Browsing by Author "Penev, Evgeni S."

Now showing 1 - 5 of 5
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    Carbon Nanotubes and Related Nanomaterials: Critical Advances and Challenges for Synthesis toward Mainstream Commercial Applications
    (American Chemical Society, 2018) Rao, Rahul; Pint, Cary L.; Islam, Ahmad E.; Weatherup, Robert S.; Hofmann, Stephan; Meshot, Eric R.; Wu, Fanqi; Zhou, Chongwu; Dee, Nicholas; Amama, Placidus B.; Carpena-Nuñez, Jennifer; Shi, Wenbo; Plata, Desiree L.; Penev, Evgeni S.; Yakobson, Boris I.; Balbuena, Perla B.; Bichara, Christophe; Futaba, Don N.; Noda, Suguru; Shin, Homin; Kim, Keun Su; Simard, Benoit; Mirri, Francesca; Pasquali, Matteo; Fornasiero, Francesco; Kauppinen, Esko I.; Arnold, Michael; Cola, Baratunde A.; Nikolaev, Pavel; Arepalli, Sivaram; Cheng, Hui-Ming; Zakharov, Dmitri N.; Stach, Eric A.; Zhang, Jin; Wei, Fei; Terrones, Mauricio; Geohegan, David B.; Maruyama, Benji; Maruyama, Shigeo; Li, Yan; Adams, W. Wade; Hart, A. John
    Advances in the synthesis and scalable manufacturing of single-walled carbon nanotubes (SWCNTs) remain critical to realizing many important commercial applications. Here we review recent breakthroughs in the synthesis of SWCNTs and highlight key ongoing research areas and challenges. A few key applications that capitalize on the properties of SWCNTs are also reviewed with respect to the recent synthesis breakthroughs and ways in which synthesis science can enable advances in these applications. While the primary focus of this review is on the science framework of SWCNT growth, we draw connections to mechanisms underlying the synthesis of other 1D and 2D materials such as boron nitride nanotubes and graphene.
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    Detecting the Biopolymer Behavior of Graphene Nanoribbons in Aqueous Solution
    (Springer Nature, 2016) Wijeratne, Sithara S.; Penev, Evgeni S.; Lu, Wei; Li, Jingqiang; Duque, Amanda L.; Yakobson, Boris I.; Tour, James M.; Kiang, Ching-Hwa; Richard E. Smalley Institute for Nanoscale Science & Technology
    Graphene nanoribbons (GNR), can be prepared in bulk quantities for large-area applications by reducing the product from the lengthwise oxidative unzipping of multiwalled carbon nanotubes (MWNT). Recently, the biomaterials application of GNR has been explored, for example, in the pore to be used for DNA sequencing. Therefore, understanding the polymer behavior of GNR in solution is essential in predicting GNR interaction with biomaterials. Here, we report experimental studies of the solution-based mechanical properties of GNR and their parent products, graphene oxide nanoribbons (GONR). We used atomic force microscopy (AFM) to study their mechanical properties in solution and showed that GNR and GONR have similar force-extension behavior as in biopolymers such as proteins and DNA. The rigidity increases with reducing chemical functionalities. The similarities in rigidity and tunability between nanoribbons and biomolecules might enable the design and fabrication of GNR-biomimetic interfaces.
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    Fatigue in assemblies of indefatigable carbon nanotubes
    (AAAS, 2021) Gupta, Nitant; Penev, Evgeni S.; Yakobson, Boris I.
    Despite being one of the most consequential processes in the utilization of structural materials, fatigue at the nano- and mesoscale has been marginally explored or understood even for the most promising nanocarbon forms—nanotubes and graphene. By combining atomistic models with kinetic Monte Carlo simulations, we show that a pristine carbon nanotube under ambient working conditions is essentially indefatigable—accumulating no structural memory of prior load; over time, it probabilistically breaks, abruptly. In contrast, by using coarse-grained modeling, we demonstrate that any practical assemblies of nanotubes, e.g., bundles and fibers, display a clear gradual strength degradation in cyclic tensile loading due to recurrence and ratchet-up of slip at the tube-tube interfaces, not occurring under static load even of equal amplitude.
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    A jellium model of a catalyst particle in carbon nanotube growth
    (AIP Publishing, 2017) Artyukhov, Vasilii I.; Liu, Mingjie; Penev, Evgeni S.; Yakobson, Boris I.
    We show how a jellium model can represent a catalyst particle within the density-functional theory based approaches to the growth mechanism of carbon nanotubes (CNTs). The advantage of jellium is an abridged, less computationally taxing description of the multi-atom metal particle, while at the same time in avoiding the uncertainty of selecting a particular atomic geometry of either a solid or ever-changing liquid catalyst particle. A careful choice of jellium sphere size and its electron density as a descriptive parameter allows one to calculate the CNT–metal interface energies close to explicit full atomistic models. Further, we show that using jellium permits computing and comparing the formation of topological defects (sole pentagons or heptagons, the culprits of growth termination) as well as pentagon–heptagon pairs 5|7 (known as chirality-switching dislocation).
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    Polycrystalline morphology and mechanical strength of nanotube fibers
    (Springer Nature, 2022) Gupta, Nitant; Penev, Evgeni S.; Yakobson, Boris I.
    Correlating mechanical performance with mesoscale structure is fundamental for the design and optimization of light and strong fibers (or any composites), most promising being those from carbon nanotubes. In all forms of nanotube fiber production strategies, due to tubes’ mutual affinity, some degree of bundling into liquid crystal-like domains can be expected, causing heterogeneous load transfer within and outside these domains, and having a direct impact on the fiber strength. By employing large-scale coarse-grained simulations, we demonstrate that the strength s of nanotube fibers with characteristic domain size D scales as s ~ 1/D, while the degree of longitudinal/axial disorder within the domains (akin to a smectic ↔ nematic phase transition) can substantially mitigate this dependence.