Separation Of Single-walled Carbon Nanotubes Research Articles

Interaction between single-walled carbon nanotubes and chromatography gel during size separation

In this study, we investigate the underlying mechanism by which chromatography can be used for the separation of single-walled carbon nanotubes (SWNTs) on the basis of their diameter or length, with a view to optimizing this popular process. Using the knowledge gained through diffusion ordered spectroscopy nuclear magnetic resonance (DOSY NMR) analysis and chromatographic experiments, we demonstrate the feasibility of separating SWNTs on the basis of diameter and length simultaneously within the one chromatography column. These findings are of relevance not just to the understanding of SWNT separation processes, but also to the industrial use of size-separated SWNTs.

Chirality-controlled growth of single-walled carbon nanotubes via nanotube cloning

Single-walled carbon nanotubes (SWNTs) have been intensively studied in the last two decades due to their remarkable electronic, thermal, mechanical, and optical properties. The major hurdle toward electronic applications is the difficulty to control chirality that determines their electronic properties. Since metallic and semiconducting nanotubes are mixed in as-grown materials produced by general growth methods, either chirality selective growth or separation of SWNTs is essential to electronic applications such as armchair quantum wires, transparent electrodes, and thin film transistors. This review article focused on nanotube cloning with chirality-selective growth and also dealt with other efforts on type-selective (metallic or semiconducting) growth of SWNTs.

Correction to Separation of Single-Walled Carbon Nanotubes with a Gel Permeation Chromatography System

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionCorrection to Separation of Single-Walled Carbon Nanotubes with a Gel Permeation Chromatography SystemBenjamin S. Flavel*, Katherine E. Moore, Moritz Pfohl, Manfred M. Kappes, and Frank Hennrich*Cite this: ACS Nano 2014, 8, 9, 9687Publication Date (Web):August 25, 2014Publication History Received21 August 2014Published online25 August 2014Published inissue 23 September 2014https://doi.org/10.1021/nn504707kCopyright © 2014 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views2665Altmetric-Citations3LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (42 KB) Get e-AlertsSUBJECTS:Carbon nanotubes,Gel permeation chromatography,Nanoscale,Nanotechnology Get e-Alerts

Coarse-Grained Model for Sequence-Dependent Adsorption of ssDNA on Carbon Nanotubes

Single-walled carbon nanotubes (SWCNTs) have extraordinary properties due to their symmetry, high aspect ratio, and thermal conductivity, all of which make them attractive toward many applications in medicine, nanotechnology, electronics, optics, and other fields. ssDNA is known to form stable dispersions of SWCNTs, and depending on its sequence can remarkably enable separation of SWCNTs of a particular chirality. In this work, we use a minimalist coarse-grained simulation model to explore general aspects of the sequence-dependent interaction of ssDNA with SWCNTs. Oligomeric chains of guanine and thymine nucleobases were investigated, revealing a significant difference in the thermodynamic behavior of three investigated sequences. G12 was found to adsorb most readily owing to the strong and stable stacking interactions between its bases and the nanotube surface. On the other hand, the smaller thymine bases allow the T12 chains to form stacking interactions between neighboring bases as well as with the nanotube simultaneously. (GT)6 interacts most weakly with the SWCNT and reveals a greater sensitivity toward nanotubes with different radii, in contrast to the homo-oligomers. The uniqueness of each sequence is attributed to geometric as well as energetic differences between neighboring bases.

Evaluation of Critical Parameters in the Separation of Single-Wall Carbon Nanotubes through Selective Adsorption onto Hydrogels

The electronic-type separation of single-wall carbon nanotubes (SWCNTs) by selective adsorption onto hydrogel surfaces has become a highly researched method. However, large variations in both SWCNT dispersion and separation protocols have been reported, making it difficult to elucidate whether changes to dispersion state or separation parameters are responsible for the observations reported in the literature. This study systematically evaluates the role that hydrogel type (dextran- or agarose-based) and SWCNT loading concentration have on separation quality, throughput, and reproducibility. For dextran-based gels, increased dextran concentration rather than cross-linker concentration improves retention and selectivity, suggesting that hydroxyl groups rather than linker molecules are the active adsorption sites. SWCNTs have much stronger interactions with agarose- than dextran-based gels. This stronger adsorption capacity combined with the improved retention of SWCNTs at higher agarose concentration sugges...

The dependence of SO3 dissociation on the diameter of single-wall carbon nanotubes based on first-principles calculations

The dissociation of SO3 molecules on the walls of armchair (m, m) (m=3, 5) and zigzag (n, 0) (n=5–10) single-wall carbon nanotubes (SWCNTs) was investigated using first-principles calculations. The calculated reaction enthalpies and energy barriers show a nearly linear decrease with decreasing tube diameter. Our results indicate that the dissociation of SO3 on the walls of SWCNTs is strongly dependent on the tube diameter for the selective etching of SWCNTs with small diameters (d<1nm) by gaseous SO3. Our study sheds light on effective separation of SWCNTs for their practical application in many fields.

Invited Presentation: Ultimate Separation and Applications of Single-Wall Carbon Nanotubes

Single-wall carbon nanotubes (SWCNTs) have attracted great attention for 20 years, because of their excellent physical properties. Especially, intrinsic high electron and hole mobilities are very attractive for the electronic device applications. However, mixed chirality production has been one of the most serious problems for both basic research and practical applications. To solve this problem, we have investigated separation methods of SWCNTs using gel column chromatography from 2008. Recently, we have clarified the separation mechanism of gel based separation methods, and realized high-purity and high-yield metal/semiconductor separation of SWCNTs as well as chirality separations. High quality sorted SWCNTs can be used for various applications such as thin film transistors and thermoelectric devices. We will show the latest results on the separation and the applications of SWCNTs.

Diporphyrin and Dipyrene Nanocalipers for Discrimination of Diameter and Metallicity in Single-Walled Carbon Nanotubes

We have been developing host-guest methodology for separation of single-walled carbon nanotubes (SWNTs) according to the handedness and diameter with gable-type chiral diporphyrins, designated as diporphyrin nanotweezers, consisting of two porphyrins and rigid spacer in between [1-4]. In this paper, we will talk about next generation of the host molecules focusing on larger diameter of SWNTs, named “nanocalipers” (Figure 1) [5,6].X. Peng, N. Komatsu,* S. Bhattacharya, T. Shimawaki, S. Aonuma, T. Kimura, A. Osuka, "Optically Active Single-Walled Carbon Nanotubes", Nature Nanotechnology, 2 (6), 361-365 (2007)G. Liu, F. Wang, X. Peng, A. F. M. M. Rahman, A. K. Bauri, and N. Komatsu, "Separation of Left- and Right-Handed Structures of Single-Walled Carbon Nanotubes through Molecular Recognition" Handbook of Biomedical Applications of Carbon Nanomaterials; K. M. Kadish and F. D'souza, Eds.; World Scientific: vol. 3, pp. 203-232 (2012).A. F. M. M. Rahman, F. Wang, K. Matsuda, T. Kimura, and N. Komatsu,* "Diameter-based separation of single-walled carbon nanotubes through selective extraction with dipyrene nanotweezers" Chem. Sci., 2 (5), 862-867 (2011) [highlighted at the inside front cover].F. Wang, K. Matsuda, A. F. M. M. Rahman, X. Peng, T. Kimura, and N. Komatsu,* "Simultaneous Discrimination of Handedness and Diameter of Single-Walled Carbon Nanotubes (SWNTs) with Chiral Diporphyrin Nanotweezers Leading to Enrichment of Single Enantiomer of (6,5)-SWNTs", J. Am. Chem. Soc., 132 (31), 10876-10881 (2010).G. Liu, A. F. M. M. Rahman, S. Chaunchaiyakul, T. Kimura, Y. Kuwahara, N. Komatsu,* "Bis(tert-butylpyrene) Nanotweezers and Nanocalipers: Enhanced Extraction and Recognition Abilities for Single-Walled Carbon Nanotubes", Chem. Eur. J., published online (DOI: 10.1002/chem.201302799).G. Liu, F. Wang, S. Chunchaiyakul, Y. Saito, A. K. Bauri, T. Kimura, Y. Kuwahara, N. Komatsu,* "Simultaneous Discrimination of Diameter, Handedness, and Metallicity of Single-Walled Carbon Nanotubes with Chiral Diporphyrin Nanocalipers", J. Am. Chem. Soc., 135 (12), 4805-4814 (2013) [highlighted in Chemical & Engineering News, 91 (12), p. 34, March 25, 2013].

Invited Presentation: Application and Thermodynamics of Aqueous Two-Phase Partitioning for Chirality Separation of Single-Wall Carbon Nanotubes Using Surfactants

The recent development of aqueous two-phase extraction (ATPE) as a method for separating single-wall carbon nanotubes (SWCNTs) provides a scalable method for isolating many individual species of SWCNT via solution processing. Systematic investigation of ATPE separation utilizing different combinations of surfactants, co-surfactants, polymers, and salts has revealed methods for isolating individual species of nanotubes up to > 1.2 nm in diameter. In this presentation I will provide an update on our separation results using surfactant(s) and on understanding achieved through temperature controlled partitioning experiments on pre-separated samples.

Invited Presentation: The Role of Dispersing Molecules on the Separation and Optical Properties of Carbon Nanotubes

When studying the optical properties of single-walled carbon nanotubes (SWCNTs), it is known that the dispersing agent(s) play an important role in the observed optical and electronic properties as well as in the separation of tubes. However, fundamental and applied reports are hindered by poor control over the interaction between the dispersant molecules and the nanotubes. Here I will discuss how interfacial chemistry affects the separation of SWCNTs and their optical properties. Compelling spectroscopic evidence has shown that surfactant composition, concentration, and structure are crucial factors to separate SWCNTs and obtain highly stable and fluorescent nanotube dispersions.

Specific DNA Sequences for the Purification of Single-Wall Carbon Nanotube Species in Polymer Aqueous Two-Phase Systems

A systematic purification of single-chirality species of single-wall carbon nanotubes (SWCNT) from their synthetic mixture provides foundation for many fundamental studies and technological applications of SWCNT. Previous study demonstrated a robust separation of SWCNT dispersed in bile salt surfactants according to their diameter and metallicity in a polymer aqueous two-phase (ATP) system. In this work, specific DNA sequences were utilized as an effective approach for recognition of specific SWCNT chirality and their subsequent purification using the ATP separation method. We show that many single chirality SWCNTs in a synthetic mixture can be obtained in very high purity. The combination of DNA sequence recognition of specific SWCNT structure and the rapid and tunable ATP separation method open a new route for sorting nanotube into each and every single-chirality species. In addition, the feasibility of volume scale-up in ATP separation allows sufficient materials to be obtained for fundamental studies and application development. Further exploration of DNA recognition sequences in ATP separation method and new polymer ATP systems will be the main focus of our future studies in carbon nanotube sorting.

Quantitative Theory of Adsorptive Separation for the Electronic Sorting of Single-Walled Carbon Nanotubes

Recently, several important advances in techniques for the separation of single-walled carbon nanotubes (SWNTs) by chiral index have been developed. These new methods allow for the separation of SWNTs through selective adsorption and desorption of different (n,m) chiral indices to and from a specific hydrogel. Our group has previously developed a kinetic model for the chiral elution order of separation; however, the underlying mechanism that allows for this separation remains unknown. In this work, we develop a quantitative theory that provides the first mechanistic insights for the separation order and binding kinetics of each SWNT chirality (n,m) based on the surfactant-induced, linear charge density, which we find ranges from 0.41 e(-)/nm for (7,3) SWNTs in 17 mM sodium dodecyl sulfate (SDS) to 3.32 e(-)/nm for (6,5) SWNTs in 105 mM SDS. Adsorption onto the hydrogel support is balanced by short-distance hard-surface and long-distance electrostatic repulsive SWNT/substrate forces, the latter of which we postulate is strongly dependent on surfactant concentration and ultimately leads to gel-based single-chirality semiconducting SWNT separation. These molecular-scale properties are derived using bulk-phase, forward adsorption rate constants for each SWNT chirality in accordance with our previously published model. The theory developed here quantitatively describes the experimental elution profiles of 15 unique SWNT chiralities as a function of anionic surfactant concentration between 17 and 105 mM, as well as phenomenological observations of the impact of varying preparatory conditions such as extent of ultrasonication and ultracentrifugation. We find that SWNT elution order and separation efficiency are primarily driven by the morphological change of SDS surfactant wrapping on the surface of the nanotube, mediated by SWNT chirality and the ionic strength of the surrounding medium. This work provides a foundational understanding for high-purity, preparative-scale separation of as-produced SWNT mixtures into isolated, single-chirality fractions.

Separation of single-walled carbon nanotubes using aqueous two-phase system

The separation of metallic single-walled carbon nanotubes (M-SWCNTs) from semiconducting single-walled carbon nanotubes (S-SWCNTs) in as-received SWCNTs is an important step to integrate carbon nanotubes into electronic applications. In this study, the effect of molecular weight (Mw) of polyethylene glycol (PEG) on the separation of M-SWCNTs from as-received SWCNTs using aqueous two-phase system (ATPS) consist of PEG, dextran, organic solvent N-methylpyrrolidone (NMP) and water has been investigated. PEG with Mw 6000 and 10,000 showed higher partition coefficient (K) and yield (Y). The semiconducting single-walled carbon nanotube (S-SWCNT) was attracted to the bottom phase. Varying the concentration of PEG 6000 and dextran could enrich the purity of M-SWCNT in the top phase to 0.2574 compared to the pristine value of 0.1506. The volume ratio (VR) that gave the highest enrichment of M-SWCNT is found to be 1.5. However, there was no significant changes in purification factor (PF) and purity when the concentration of NMP and water were manipulated. This finding provides a solid foundation for the studies of ATPS to separate different species of SWCNTs.

Separation of Single-Walled Carbon Nanotubes with a Gel Permeation Chromatography System

A gel permeation chromatography system is used to separate aqueous sodium dodecyl sulfate suspensions of single-walled carbon nanotubes (SWCNTs). This automated procedure requires no precentrifugation, is scalable, and is found to yield monochiral SWCNT fractions of semiconducting SWCNTs with a purity of 61-95%. Unsorted and resulting monochiral fractions are characterized using optical absorption and photoluminescence spectroscopy.

Gel electrophoresis using a selective radical for the separation of single-walled carbon nanotubes.

We have applied agarose gel electrophoresis (AGE) to single-walled carbon nanotubes (SWNTs) that have been pre-reacted with metallic-selective ionic radicals and then re-suspended with sodium cholate (SC) surfactant to obtain highly purified (up to 98%) semiconducting single-walled carbon nanotubes (s-SWNTs). The proposed combination method exploits the preferential reactivity with the metallic nanotube of the radicals generated from an azo naphthalene compound (Direct Blue 71(I)) to preferentially increase the surface charge, and therefore the electrophoretic mobilities, of the metallic nanotube population under the influence of the electric field in AGE. The excellent separation achieved was verified by UV-vis-NIR and Raman spectroscopy as well as by the performance of field effect transistors fabricated with semiconducting-enriched SWNTs. FETs fabricated with -assisted AGE-separated semiconducting nanotubes exhibited mobilities of ∼3.6 to 11.7 cm(2) V(-1) s(-1) and on/off ratios from 10(2) to 10(6).

Photophoretic separation of single-walled carbon nanotubes: a novel approach to selective chiral sorting

For over two decades single-walled carbon nanotubes (SWCNTs) have been used in a broad range of electronic and optical applications, however the selective chiral sorting of SWCNTs with guaranteed optoelectronics characteristics is imperative to the industrial realization of such applications. In this paper we provide the results of modeling an optical sorting method that utilizes the inherent opto-electronic properties of the SWCNTs, thus guaranteeing the properties of the extracted populations. Utilizing the resonant transfer of photonic momentum, we simulate chiral sorting of two chiral populations in an aqueous environment based on the frequency dependent optical absorption properties of the nanotubes. We show that photonic sorting is not only feasible, but may be up to faster than density gradient centrifugation techniques. Our simulations investigate the effects of laser power, temperature and orientation. We find that 96% purity can be achieved in less than 12 minutes by operating at 9 × 10(7) W m(-2) (20 mW in a 20 μm chamber) at elevated temperatures.

Bis(tert‐butylpyrene) Nanotweezers and Nanocalipers: Enhanced Extraction and Recognition Abilities for Single‐Walled Carbon Nanotubes

We developed a host-guest methodology for separation of single-walled carbon nanotubes (SWNTs) according to the handedness, diameter and metallicity by the use of diporphyrin nanotweezers and nanocalipers. Although the pyrene has been frequently used to replace porphyrin, due to a similar affinity to the surface of SWNTs and better availability, the extraction and recognition abilities of dipyrene nanotweezers were not so good as those of diporphyrin ones as we reported previously. However, introduction of a tert-butyl substituent at the 7'-position of 2-pyrene is found to enhance the extraction and recognition abilities of dipyrene nanotweezers and nanocalipers. That is, (6,5)-SWNTs were obtained in high purity by use of bis(tert-butylpyrene) nanotweezers with a phenanthrene spacer and metallic SWNTs were highly enriched by use of bis(tert-butylpyrene) nanocalipers with a carbazole-anthracene-carbazole spacer.

Dielectrophoretic separation of metallic arc-discharge single-walled carbon nanotubes in a microfluidic channel

Electronic type-dependent separation of single-walled carbon nanotubes (SWNTs), preserving pristine crystallinity and length, is of great interest since mixtures of semiconducting and metallic species are produced by current synthesis methods. Here we separated highly-enriched metallic SWNTs, synthesized by the arc-discharge method, by dielectrophoresis in a microfluidic channel. The design of microelectrodes was optimized to prevent the nanotube deposition on the electrodes for prolonged operation of the microfluidic chip. The average length of separated highly crystalline metallic SWNTs was relatively long (2–2.4μm).

PH- and Solute-Dependent Adsorption of Single-Wall Carbon Nanotubes onto Hydrogels: Mechanistic Insights into the Metal/Semiconductor Separation

The gel separation of single-wall carbon nanotubes (SWCNTs) suspended in sodium dodecyl sulfate (SDS) is expected to be one of the most successful methods of large-scale and high-purity separation. Understanding the mechanism of the gel separation helps improve the quality and quantity of separation and reveals the colloidal behaviors of SWCNTs, which reflects their band structures. In this study, we characterize the pH- and solute-dependent adsorption of SWCNTs onto agarose and Sephacryl hydrogels and provide a mechanistic model of the metal/semiconductor separation. The adsorbability of SWCNTs is substantially reduced under acidic pH conditions. Importantly, the pH dependence differs between metallic and semiconducting species; therefore, the adsorbability is related to the band-structure-dependent oxidation of the SWCNTs. Oxidation confers positive charges on SWCNTs, and these charges enhance the electrostatic interactions of the SWCNTs with SDS, thereby leading to the condensation of SDS on the SWCNTs. This increase in SDS density reduces the interactions between the SWCNTs and hydrogels. Under highly basic conditions, such as pH ∼12.5, or in the presence of salts, the adsorption is dissociative because of the condensation of SDS on the SWCNTs through electrostatic screening by counterions. Desorption of the SWCNTs from the hydrogels due to the addition of urea implies a hydrophobic interface between SDS-dispersed SWCNTs and the hydrogels. These results suggest that the metal/semiconductor separation can be explained by the alteration of the interaction between SDS-dispersed SWCNTs and the hydrogels through changes in the conformation of SDS on the SWCNTs depending on the SWCNTs' band structures.

Direct Intermolecular Force Measurements between Functional Groups and Individual Metallic or Semiconducting Single‐Walled Carbon Nanotubes

Many electronic applications of single-walled carbon nanotubes (SWNTs) require electronic homogeneity in order to maximally exploit their outstanding properties. Non-covalent separation is attractive as it is scalable and results in minimal alteration of nanotube properties. However, fundamental understanding of the metallicity-dependence of functional group interactions with nanotubes is still lacking; this lack is compounded by the absence of methods to directly measure these interactions. Herein, a novel technology platform based on a recently developed atomic force microscopy (AFM) mode is reported which directly quantifies the adhesion forces between a chosen functional group and individual nanotubes of known metallicity, permitting comparisons between different metallicity. These results unambiguously show that this technology platform is able to discriminate the subtle adhesion force differences of a chosen functional group with pure metallic as opposed to pure semiconducting nanotubes. This new method provides a route towards rapid advances in understanding of non-covalent interactions of large libraries of compounds with nanotubes of varying metallicity and diameter; presenting a superior tool to assist the discovery of more effective metallicity-based SWNT separation agents.