Agglomeration Dynamics of 1D Materials: Gas‐Phase Collision Rates of Nanotubes and Nanorods

Boies, Adam M.; Hoecker, Christian; Bhalerao, Ajinkya; Kateris, Nikolaos; Verpilliere, Jean de La; Graves, Brian; Smail, Fiona

doi:10.1002/smll.201900520

Cited by 28 publications

(29 citation statements)

References 62 publications

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“…In process C1, a stable aerosol bubble is blown while process C2 transforms the bubble from an aerosol into an aerogel. The SWCNTs in C1 aerosol have some interaction, [ 11,13 ] which is different in the general aerosol, [ 14 ] and could be transformed under a suitable condition into SWCNT aerogel in C2 as a final product. [ 13,15 ] BACVD essentially combines a blowing SWCNT‐aerosol technique with FCCVD for CNT synthesis.…”

Section: Figurementioning

confidence: 99%

Transparent and Freestanding Single‐Walled Carbon Nanotube Films Synthesized Directly and Continuously via a Blown Aerosol Technique

et al. 2020

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Single‐walled carbon nanotube (SWCNT) films are promising materials as flexible transparent conductive films (TCFs). Here, inspired by the extrusion blown plastic film technique and the SWCNT synthesis approach by floating catalyst chemical vapor deposition (FCCVD), a novel blown aerosol chemical vapor deposition (BACVD) method is reported to directly and continuously produce freestanding SWCNT TCFs at several hundred meters per hour. The synthesis mechanism, involving blowing a stable aerosol bubble and transforming the bubble into an aerogel, is investigated, and a general phase diagram is established for this method. For the SWCNT TCFs via BACVD, both carbon conversion efficiency and SWCNT TCF yield can reach three orders of magnitude higher than those with the conventional FCCVD. The film displays a sheet resistance of 40 ohm sq−1 at 90% transmittance after being doped, representing the record performance based on large‐scale SWCNT films. Transparent, flexible, and stretchable electrodes based on BACVD films are demonstrated. Moreover, this high‐throughput method of producing SWCNT TCFs can be compatible with the roll‐to‐roll process for mass production of flexible displays, touch screens, solar cells, and solid‐state lighting, and is expected to have a broad and long‐term impact on many fields from consumer electronics to energy conversion and generation.

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Section: Figurementioning

confidence: 99%

Transparent and Freestanding Single‐Walled Carbon Nanotube Films Synthesized Directly and Continuously via a Blown Aerosol Technique

et al. 2020

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“…It is experimentally observed that these bundles consist of about 3-20 close-packed CNTs and may be considerably longer than the individual CNTs. 5 Subsequently, the bundles collide and entangle to form a network of bundles, which is then drawn out of the furnace as fibre spun on a rotating drum, or as CNT sheets. The process of a dilute CNT aerosol to gel transition is referred to as a CNT aerogel in line with work for gas-phase spherical aggregates 6 and colloidal sol-gel systems.…”

Section: Na No Tu Be Gr Ow Th On Ca Ta Lys T Pa Rti Cle Smentioning

confidence: 99%

From Collisions to Bundles: An Adaptive Coarse-Grained Model for the Aggregation of High-Aspect-Ratio Carbon Nanotubes

et al. 2020

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We present an adaptive mesoscale model for carbon nanotube (CNT) systems. In our model, CNTs are represented as a chain of nodes connected by tensile and torsion springs to describe stretching and bending of the chain with intermolecular interactions being calculated using a mesoscopic Lennard-Jones potential. Computational adaptivity was achieved by dynamically adjusting node spacing and number during the simulation to optimise the number of simulated particles and lower computational effort. Adaptive simulations were up to five times faster than non-adaptive ones whilst quantitatively preserving all system dynamics. In particular, the model enables the study of the timescale of CNT bundling that leads to the formation of dilute CNT networks, so-called aerogels. These aerogels constitute the first step in the direct spinning of CNT fibres from chemical vapour deposition synthesis. Understanding the factors governing CNT bundling and network formation is key to controlling CNT fibre microstructure, and therefore optimising their properties. Using the model, we simulated the bundling dynamics of two CNTs with an initial point contact at varying angles for CNT lengths of up to 10 µm. We find that bundling times are an increasing function of initial collision angle and follow a power law with increasing CNT length that range from 10 −1 to 10 3 ns. We postulate that when this bundling time becomes of the same order as the CNT bundle collision time, the aerogel will form.

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“…However, CNTs form bundles, due to weak van der Waals interactions, which exhibit higher stiffness and have a greater cross‐sectional area compared to individual CNTs. [ 49 ] Furthermore, multi‐walled CNTs (MWCNTs) are also known to be stiffer compared to SWCNTs. [ 50 ] The higher stiffness and effective cross‐sectional area of these structures may significantly lower the necessary electric field strength for alignment.…”

Section: Application To Alignment Of Carbon Nanotubes In An Electric Fieldmentioning

confidence: 99%

Freely Suspended Semiflexible Chains in a Strong Aligning Field: Simple Closed‐Form Solutions for the Small‐Angle Approximation

Kloza

Elliott

2020

Macro Theory & Simulations

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chain (WLC) model [7] have computed force-extension curves and end-to-end distributions. [8-11] More recently, an empirically corrected interpolation formula was found for the force-extension relationship that nearly matches the exact numerical result for the WLC. [12] For continuous chain contour functions, one may apply the path integral formalism known from quantum mechanics [13,14] which can then be solved using mean-field theory [15] or approximations in the limit of short or long chains. [16] Exact analytical expressions for the partition function and the end-to-end distribution of the WLC model with an external field have been found for two and three dimensions. [17] However, the solution is formulated in Fourier-Laplace space and is expressed in terms of complicated continued fractions. This solution was subsequently used to derive the end-to-end distribution of the free WLC model for a fixed chain end in Fourier space in arbitrary dimensions, [18] and was also extended by a torsional stiffness component to compute the ring-closure probability of DNA. [19] Likewise, the exact end-to-end distribution was numerically computed by treating the WLC as an equivalent quantum particle [20] or by considering random walks under constraints in Fourier-Laplace space. [21] WLC models under spatial constraints have also been studied in the past. In these models, the constraints are rigid walls which the chain cannot penetrate. Early work by Odijk [22] established the existence of three regimes: the rigid rod regime for short chains, a flexible chain regime for long chains and a transition regime in between. The theory was later extended to lyotropic polymer liquid crystals. [23] Later, the partition function of the WLC with a harmonic confinement potential in the infinitely long chain limit and a lower bound on the confinement free energy in a circular tube have been found. [24] Confinement free energies for different confinement geometries have been studied for the WLC model, for example, in square and circular tubes. [25,26] An extensive review of WLC confinement theory is provided in ref. [27]. Confinement of a WLC by a harmonic potential for the displacement in two dimensions has further been studied by using Markov processes to compute the displacement distribution of the chain contour. [28] Alternatively, the structure can be modeled using the discrete Kratky-Porod model [29] which can be readily simulated with Monte Carlo (MC) techniques. [30] These techniques have been used to compute force-extension curves [31] and average shapes [32] of semiflexible chains. Furthermore, MC simulation A worm-like chain model for a single, freely suspended semiflexible macromolecule with an aligning field of arbitrary coupling order is presented. Using a small-angle approximation and Ginzburg-Landau theory, exact closed-form solutions of the model are derived in the regime of a strong aligning field in arbitrary dimensions. Expressions for the mean cosine of the chain alignment angle, orientational order parameters, and the two...

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Agglomeration Dynamics of 1D Materials: Gas‐Phase Collision Rates of Nanotubes and Nanorods

Cited by 28 publications

References 62 publications

Transparent and Freestanding Single‐Walled Carbon Nanotube Films Synthesized Directly and Continuously via a Blown Aerosol Technique

Transparent and Freestanding Single‐Walled Carbon Nanotube Films Synthesized Directly and Continuously via a Blown Aerosol Technique

From Collisions to Bundles: An Adaptive Coarse-Grained Model for the Aggregation of High-Aspect-Ratio Carbon Nanotubes

Freely Suspended Semiflexible Chains in a Strong Aligning Field: Simple Closed‐Form Solutions for the Small‐Angle Approximation

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