Carbon nanotube chemistry

This article is about chemical reactions of carbon nanotubes. For their chemical synthesis, see Synthesis of carbon nanotubes.

Carbon nanotube chemistry involves chemical reactions, which are used to modify the properties of carbon nanotubes (CNTs). CNTs can be functionalized to attain desired properties that can be used in a wide variety of applications. The two main methods of CNT functionalization are covalent and non-covalent modifications.[1]

Because of their hydrophobic nature, CNTs tend to agglomerate hindering their dispersion in solvents or viscous polymer melts. The resulting nanotube bundles or aggregates reduce the mechanical performance of the final composite. The surface of CNTs can be modified to reduce the hydrophobicity and improve interfacial adhesion to a bulk polymer through chemical attachment.

Chart summarizing options for the chemical modification of carbon nanotubes.

Covalent modification

Covalent modification of carbon nanotubes.

Covalent modification attaches a functional group onto the carbon nanotube. The functional groups can be attached onto the side wall or ends of the carbon nanotube.[1] The end caps of the carbon nanotubes have the highest reactivity due to its higher pyrimidization angle and the walls of the carbon nanotubes have lower pyrimidization angles which has lower reactivity. Although covalent modifications are very stable, the bonding process disrupts the sp2 hybridization of the carbon atoms because a σ-bond is formed.[1] The disruption of the extended sp2 hybridization typically decreases the conductance of the carbon nanotubes.

Oxidation

The purification and oxidation of carbon nanotubes (CNTs) has been well represented in literature.[2][3][4][5] These processes were essential for low yield production of carbon nanotubes where carbon particles, amorphous carbon particles and coatings comprised a significant percentage of the overall material and are still important for the introduction of surface functional groups.[6] During acid oxidation, the carbon-carbon bonded network of the graphitic layers is broken allowing the introduction of oxygen units in the form of carboxyl, phenolic and lactone groups,[7] which have been extensively exploited for further chemical functionalisation.[8]

First studies on oxidation of carbon nanotubes involved a gas-phase reactions with nitric acid vapor in air, which indiscriminately functionalized the carbon nanotubes with carboxylic, carbonyl or hydroxyl groups.[9] In liquid-phase reactions, carbon nanotubes were treated with oxidizing solutions of nitric acid or a combination of nitric and sulfuric acid to the same effect.[10] However, overoxidation may occur causing the carbon nanotube to break up into fragments, which are known as carbonaceous fragments.[11] Xing et al. revealed sonication assisted oxidation, with sulfuric and nitric acid, of carbon nanotubes and produced carbonyl and carboxyl groups.[12] After the oxidation reaction in acidic solution, treatment with hydrogen peroxide limited the damage on the carbon nanotube network.[13] Single-walled carbon nanotubes can be shortened in a scalable manner using oleum (100% H2SO4 with 3% SO3) and nitric acid. The nitric acid cuts carbon nanotubes while the oleum creates a channel.[1]

In one type of chemical modification, aniline is oxidized to a diazonium intermediate. After expulsion of nitrogen, it forms a covalent bond as an aryl radical:[14][15]

Esterification/Amidation

Carboxylic groups are used as the precursor for most esterification and amidation reactions. The carboxylic group is converted into an acyl chloride with the use of thionyl or oxalyl chloride which is then reacted with the desired amide, amine, or alcohol.[1] Carbon nanotubes have been deposited on with silver nanoparticles with the aid of amination reactions. Amide functionalized carbon nanotubes have been shown to chelate silver nanoparticles. Carbon nanotubes modified with acyl chloride react readily with highly branched molecules such as poly(amindoamine), which acts as a template for silver ion and later being reduced by formaldehyde.[16] Amino-modified carbon nanotubes can be prepared by reacting ethylenediamine with an acyl chloride functionalized carbon nanotubes.[17]

Halogenation reactions

Carbon nanotubes can be treated with peroxytrifluroacetic acid to give mainly carboxylic acid and trifluroacetic functional groups.[1] The fluorinated carbon nanotubes, through substitution, can be further functionalized with urea, guanidine, thiourea and aminosilane.[18] Using the Hunsdiecker reaction, carbon nanotubes treated with nitric acid can react with iodosobenzenediacetate to iodate carbon nanotubes.[19]

Cycloaddition

Also known are protocols for cycloadditions such as Diels-Alder reactions, 1,3-dipolar cycloadditions of azomethine ylides and azide–alkyne cycloaddition reactions.[20] One example is a DA reaction assisted by chromium hexacarbonyl and high pressure.[21] The ID/IG ratio for reaction with Danishefsky’s diene is 2.6.

The most well-known 1,3 cycloaddition reaction involves azomethine ylides reacting with carbon nanotubes, which are of great interest. The addition of a pyrrolidine ring can lead to a variety of functional groups such as second-generation poly(amidoamine) dendrimers,[22] phthalocyanineaddends,[23] perfluoroalkylsilane groups,[24] and amino ethyleneglycol groups.[25] The Diels-cycloaddition reaction can occur, especially on fluorinated carbon nanotubes. They are known to undergo Diels–Alder reaction s with dienes such as 2,3-dimethyl-1,3-butadiene, anthracene, and 2-trimethylsiloxyl-1,3-butadiene.[17]

Radical addition

Top: electron micrographs showing interaction of CNTs with 4-(1-pyrenyl)phenyl radical (a) and its boronic ester (b). Bottom: corresponding models.[26]

The modification of carbon nanotubes with aryl diazonium salts was studied first by Tour et al.[27] Due to the harsh conditions needed for the in situ generated diazonium compound, other methods have been explored. Stephenson et al. reported using aniline derivatives with sodium nitrite in 96% sulfuric acid and ammonium persulfate.[28] Price et al. demonstrated that stirring carbon nanotubes in water and treating with anilines and oxidizing agents proved to be a milder reaction.[1] The diazonium chemistry functionalized carbon nanotubes which was used as a precursor to further modifications. Suzuki and Heck coupling reactions were performed on iodophenyl-functionalized carbon nanotubes.[29] Wong et al. demonstrated mild photochemical reactions to silylate the carbon nanotubes with trimethoxysilane and hexaphenyldisilane.[30]

Nucleophilic addition

Hirsch et al. conducted nucleophilic additions with organolithium and organomagnesium compounds onto carbon nanotubes. With further oxidation in air, they were able to create alkyl-modified carbon nanotubes.[31] Hirsch was also able to show the nucleophilic addition of amines by generating lithium amides, leading to amino-modified carbon nanotubes.[32]

Electrophilic addition

Nanotubes can also be alkylated with alkyl halides using lithium or sodium metal and liquid ammonia (Birch reduction conditions).[33][34] The initial nanotube salt can function as an polymerization initiator [35] and can react with peroxides to form alkoxy functionalized nanotubes [36]

The alkyl and hydroxyl modification of carbon nanotubes was demonstrated with the electrophilic addition of alkylhalides by microwave irradiation.[1] Tessonnier et al. modified carbon nanotubes with amino groups by deprotonating with butyl lithium and reacting with amino substitution.[32] Balaban et al. applied Friedel-Crafts acylation to carbon nanotubes with nitrobenzene at 180 °C along with aluminum chloride.[37]

Non-covalent modifications

Non-covalent modification of carbon nanotubes.

Non-covalent modifications utilize van der Waals forces and π-π interactions by adsorption of polynuclear aromatic compounds, surfactants, polymers or biomolecules. Non-covalent modifications do not disrupt the natural configuration of carbon nanotubes with the cost of chemical stability, and is prone to phase separation, dissociation in between two phases, in the solid state.[1]

Polynuclear aromatic compounds

Some common polynuclear aromatic compounds that are functionalized with hydrophilic or hydrophobic moieties are used to solubilize carbon nanotubes into organic or aqueous solvents. Some of these amphiphiles are phenyl, naphthalene, phenanthrene, pyrene and porphyrin systems.[38] The greater π-π stacking of aromatic amphiphiles such as pyrene amphiphiles had the best solubility compared to phenyl amphiphiles with the worse π-π stacking, lead to more solubility in water.[38] These aromatic systems can be modified with amino and carboxylic acid groups prior to functionalizing the carbon nanotubes.[39]

Biomolecules

The interaction between carbon nanotubes and biomolecules has been widely studied because of their potential to be used in biological applications.[40] The modification of the carbon nanotubes with proteins, carbohydrates, and nucleic acids are built with the bottom-up technique.[1] Proteins have high affinity to carbon nanotubes due to their diversity of amino acids being hydrophobic or hydrophilic.[1] Polysaccharides have been successfully been used to modify carbon nanotubes forming stable hybrids.[41] To make carbon nanotubes soluble in water, phospholipids such as lysoglycerophospholipids have been used.[42] The single phospholipid tail wraps around the carbon nanotube, but the double tailed phospholipids did not have the same ability.

π-π stacking and electrostatic interactions

Molecules that have bifunctionality are used to modify the carbon nanotube. One end of the molecule are polyaromatic compounds that interact with the carbon nanotube through π-π stacking. The other end of the same molecule has a functional group such as amino, carboxyl, or thiol.[1] For example, pyrene derivatives and aryl thiols were used as the linkers for various metal nanobeads such as gold, silver and platinum.[43]

Characterization

A useful tool for the analysis of derivatised nanotubes is Raman spectroscopy which shows a G-band (G for graphite) for the native nanotubes at 1580 cm−1 and a D-band (D for defect) at 1350  cm−1 when the graphite lattice is disrupted with conversion of sp² to sp³ hybridized carbon. The ratio of both peaks ID/IG is taken as a measure of functionalization. Other tools are UV spectroscopy where pristine nanotubes show distinct Van Hove singularities where functionalized tubes do not, and simple TGA analysis.

See also

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 Karousis, Nikolaos; Tagmatarchis, Nikos; Tasis, Dimitrios (2010-06-14). "Current Progress on the Chemical Modification of Carbon Nanotubes". Chemical Reviews. 110 (9): 5366–5397. doi:10.1021/cr100018g.
  2. ↑ Tsang, S. C.; Harris, P. J. F.; Green, M. L. H. (1993). "Thinning and opening of carbon nanotubes by oxidation using carbon dioxide". Nature. 362 (6420): 520. doi:10.1038/362520a0.
  3. ↑ Ajayan, P. M.; Ebbesen, T. W.; Ichihashi, T.; Iijima, S.; Tanigaki, K.; Hiura, H. (1993). "Opening carbon nanotubes with oxygen and implications for filling". Nature. 362 (6420): 522. doi:10.1038/362522a0.
  4. ↑ Tsang, S. C.; Chen, Y. K.; Harris, P. J. F.; Green, M. L. H. (1994). "A simple chemical method of opening and filling carbon nanotubes". Nature. 372 (6502): 159. doi:10.1038/372159a0.
  5. ↑ Hiura, Hidefumi; Ebbesen, Thomas W.; Tanigaki, Katsumi (1995). "Opening and purification of carbon nanotubes in high yields". Advanced Materials. 7 (3): 275. doi:10.1002/adma.19950070304.
  6. ↑ Esumi, K; Ishigami, M.; Nakajima, A.; Sawada, K.; Honda, H. (1996). "Chemical treatment of carbon nanotubes". Carbon. 34 (2): 279. doi:10.1016/0008-6223(96)83349-5.
  7. ↑ Shaffer, M; Fan, X.; Windle, A.H. (1998). "Dispersion and packing of carbon nanotubes". Carbon. 36 (11): 1603. doi:10.1016/S0008-6223(98)00130-4.
  8. ↑ Sun, Ya-Ping; Fu, Kefu; Lin, Yi; Huang, Weijie (2002). "Functionalized Carbon Nanotubes: Properties and Applications". Accounts of Chemical Research. 35 (12): 1096–104. doi:10.1021/ar010160v. PMID 12484798.
  9. ↑ Xia, Wei; Jin, Chen; Kundu, Shankhamala; Muhler, Martin (2009-03-01). "A highly efficient gas-phase route for the oxygen functionalization of carbon nanotubes based on nitric acid vapor". Carbon. 47 (3): 919–922. doi:10.1016/j.carbon.2008.12.026.
  10. ↑ Datsyuk, V.; Kalyva, M.; Papagelis, K.; Parthenios, J.; Tasis, D.; Siokou, A.; Kallitsis, I.; Galiotis, C. (2008-05-01). "Chemical oxidation of multiwalled carbon nanotubes". Carbon. 46 (6): 833–840. doi:10.1016/j.carbon.2008.02.012.
  11. ↑ Bergeret, Céline; Cousseau, Jack; Fernandez, Vincent; Mevellec, Jean-Yves; Lefrant, Serge (2008-10-23). "Spectroscopic Evidence of Carbon Nanotubes' Metallic Character Loss Induced by Covalent Functionalization via Nitric Acid Purification". The Journal of Physical Chemistry C. 112 (42): 16411–16416. doi:10.1021/jp806602t.
  12. ↑ Xing, Yangchuan; Li, Liang; Chusuei, Charles C.; Hull, Robert V. (2005-04-01). "Sonochemical Oxidation of Multiwalled Carbon Nanotubes". Langmuir. 21 (9): 4185–4190. doi:10.1021/la047268e.
  13. ↑ Avilés, F.; Cauich-Rodríguez, J. V.; Moo-Tah, L.; May-Pat, A.; Vargas-Coronado, R. (2009-11-01). "Evaluation of mild acid oxidation treatments for MWCNT functionalization". Carbon. 47 (13): 2970–2975. doi:10.1016/j.carbon.2009.06.044.
  14. ↑ Price, B. K.; Tour, J. M. (2006). "Functionalization of Single-Walled Carbon Nanotubes "On Water"". Journal of the American Chemical Society. 128 (39): 12899–12904. doi:10.1021/ja063609u. PMID 17002385.
  15. ↑ The oxidizing agent is isoamyl nitrite and because the optimized reaction takes place as a suspension in water it is a so-called on water reaction.
  16. ↑ Tao, Lei; Chen, Gaojian; Mantovani, Giuseppe; York, Steve; Haddleton, David M. "Modification of multi-wall carbon nanotube surfaces with poly(amidoamine) dendrons: Synthesis and metal templating". pubs.rsc.org. doi:10.1039/B609065F.
  17. 1 2 Jeong, J. S.; Jeon, S. Y.; Lee, T. Y.; Park, J. H.; Shin, J. H.; Alegaonkar, P. S.; Berdinsky, A. S.; Yoo, J. B. (2006-11-01). "Fabrication of MWNTs/nylon conductive composite nanofibers by electrospinning". Diamond and Related Materials. Proceedings of the joint 11th International Conference on New Diamond Science and Technology and the 9th Applied Diamond Conference 2006ICNDST-ADC 2006. 15 (11–12): 1839–1843. doi:10.1016/j.diamond.2006.08.026.
  18. ↑ Valentini, Luca; Macan, Jelena; Armentano, Ilaria; Mengoni, Francesco; Kenny, Josè M. (2006-09-01). "Modification of fluorinated single-walled carbon nanotubes with aminosilane molecules". Carbon. 44 (11): 2196–2201. doi:10.1016/j.carbon.2006.03.007.
  19. ↑ Coleman, Karl S.; Chakraborty, Amit K.; Bailey, Sam R.; Sloan, Jeremy; Alexander, Morgan (2007-03-01). "Iodination of Single-Walled Carbon Nanotubes". Chemistry of Materials. 19 (5): 1076–1081. doi:10.1021/cm062730x.
  20. ↑ Kumar, I.; Rana, S.; Cho, J. W. (2011). "Cycloaddition Reactions: A Controlled Approach for Carbon Nanotube Functionalization". Chemistry: A European Journal. 17 (40): 11092. doi:10.1002/chem.201101260.
  21. ↑ Ménard-Moyon, C. C.; Dumas, F. O.; Doris, E.; Mioskowski, C. (2006). "Functionalization of Single-Wall Carbon Nanotubes by Tandem High-Pressure/Cr(CO)6 Activation of Diels−Alder Cycloaddition". Journal of the American Chemical Society. 128 (46): 14764–14765. doi:10.1021/ja065698g. PMID 17105260.
  22. ↑ Campidelli, Stéphane; Sooambar, Chloé; Lozano Diz, Enrique; Ehli, Christian; Guldi, Dirk M.; Prato, Maurizio (2006-09-01). "Dendrimer-Functionalized Single-Wall Carbon Nanotubes: Synthesis, Characterization, and Photoinduced Electron Transfer". Journal of the American Chemical Society. 128 (38): 12544–12552. doi:10.1021/ja063697i.
  23. ↑ Ballesteros, Beatriz; de la Torre, Gema; Ehli, Christian; Aminur Rahman, G. M.; Agulló-Rueda, F.; Guldi, Dirk M.; Torres, Tomás (2007-04-01). "Single-Wall Carbon Nanotubes Bearing Covalently Linked Phthalocyanines − Photoinduced Electron Transfer". Journal of the American Chemical Society. 129 (16): 5061–5068. doi:10.1021/ja068240n.
  24. ↑ Georgakilas, Vasilios; Bourlinos, Athanasios B.; Zboril, Radek; Trapalis, Christos (2008-05-01). "Synthesis, Characterization and Aspects of Superhydrophobic Functionalized Carbon Nanotubes". Chemistry of Materials. 20 (9): 2884–2886. doi:10.1021/cm7034079.
  25. ↑ Fabre, Bruno; Hauquier, Fanny; Herrier, Cyril; Pastorin, Giorgia; Wu, Wei; Bianco, Alberto; Prato, Maurizio; Hapiot, Philippe; Zigah, Dodzi (2008-07-01). "Covalent Assembly and Micropatterning of Functionalized Multiwalled Carbon Nanotubes to Monolayer-Modified Si(111) Surfaces". Langmuir. 24 (13): 6595–6602. doi:10.1021/la800358w.
  26. ↑ "Molecular interactions on single-walled carbon nanotubes revealed by high-resolution transmission microscopy". Nature Communications. 6: 7732. 2015. doi:10.1038/ncomms8732.
  27. ↑ Hayden, Hugh; Gun’ko, Yurii K.; Perova, Tatiana S. (2007-02-12). "Chemical modification of multi-walled carbon nanotubes using a tetrazine derivative". Chemical Physics Letters. 435 (1–3): 84–89. doi:10.1016/j.cplett.2006.12.035.
  28. ↑ Stephenson, Jason J.; Hudson, Jared L.; Azad, Samina; Tour, James M. (2006-01-01). "Individualized Single Walled Carbon Nanotubes from Bulk Material Using 96% Sulfuric Acid as Solvent". Chemistry of Materials. 18 (2): 374–377. doi:10.1021/cm052204q.
  29. ↑ Cheng, Fuyong; Imin, Patigul; Maunders, Christian; Botton, Gianluigi; Adronov, Alex (2008-03-04). "Soluble, Discrete Supramolecular Complexes of Single-Walled Carbon Nanotubes with Fluorene-Based Conjugated Polymers". Macromolecules. 41 (7): 2304–2308. doi:10.1021/ma702567y.
  30. ↑ Martín, Roberto; Jiménez, Liliana; Alvaro, Mercedes; Scaiano, Juan C.; Garcia, Hermenegildo (2010-06-25). "Two-Photon Chemistry in Ruthenium 2,2′-Bipyridyl-Functionalized Single-Wall Carbon Nanotubes". Chemistry: A European Journal. 16 (24): 7282–7292. doi:10.1002/chem.200903506.
  31. ↑ Graupner, Ralf; Abraham, Jürgen; Wunderlich, David; Vencelová, Andrea; Lauffer, Peter; Röhrl, Jonas; Hundhausen, Martin; Ley, Lothar; Hirsch, Andreas (2006-05-01). "Nucleophilic−Alkylation−Reoxidation: A Functionalization Sequence for Single-Wall Carbon Nanotubes". Journal of the American Chemical Society. 128 (20): 6683–6689. doi:10.1021/ja0607281.
  32. 1 2 Syrgiannis, Zois; Hauke, Frank; Röhrl, Jonas; Hundhausen, Martin; Graupner, Ralf; Elemes, Yiannis; Hirsch, Andreas (2008-05-01). "Covalent Sidewall Functionalization of SWNTs by Nucleophilic Addition of Lithium Amides". European Journal of Organic Chemistry. 2008 (15): 2544–2550. doi:10.1002/ejoc.200800005.
  33. ↑ Liang, F.; Sadana, A. K.; Peera, A.; Chattopadhyay, J.; Gu, Z.; Hauge, R. H.; Billups, W. E. (2004). "A Convenient Route to Functionalized Carbon Nanotubes". Nano Letters. 4 (7): 1257. Bibcode:2004NanoL...4.1257L. doi:10.1021/nl049428c.
  34. ↑ Wunderlich, D.; Hauke, F.; Hirsch, A. (2008). "Preferred functionalization of metallic and small-diameter single walled carbon nanotubes via reductive alkylation". Journal of Materials Chemistry. 18 (13): 1493. doi:10.1039/b716732f.
  35. ↑ Liang, F.; Beach, J. M.; Kobashi, K.; Sadana, A. K.; Vega-Cantu, Y. I.; Tour, J. M.; Billups, W. E. (2006). "In Situ Polymerization Initiated by Single-Walled Carbon Nanotube Salts". Chemistry of Materials. 18 (20): 4764. doi:10.1021/cm0607536.
  36. ↑ Mukherjee, A.; Combs, R.; Chattopadhyay, J.; Abmayr, D. W.; Engel, P. S.; Billups, W. E. (2008). "Attachment of Nitrogen and Oxygen Centered Radicals to Single-Walled Carbon Nanotube Salts". Chemistry of Materials. 20 (23): 7339. doi:10.1021/cm8014226.
  37. ↑ Balaban, T. S.; Balaban, M. C.; Malik, S.; Hennrich, F.; Fischer, R.; Rösner, H.; Kappes, M. M. (2006-10-17). "Polyacylation of Single-Walled Nanotubes under Friedel–Crafts Conditions: An Efficient Method for Functionalizing, Purifying, Decorating, and Linking Carbon Allotropes". Advanced Materials. 18 (20): 2763–2767. doi:10.1002/adma.200600138.
  38. 1 2 Tomonari, Yasuhiko; Murakami, Hiroto; Nakashima, Naotoshi (2006-05-15). "Solubilization of Single-Walled Carbon Nanotubes by using Polycyclic Aromatic Ammonium Amphiphiles in Water—Strategy for the Design of High-Performance Solubilizers". Chemistry: A European Journal. 12 (15): 4027–4034. doi:10.1002/chem.200501176.
  39. ↑ Simmons, Trevor J.; Bult, Justin; Hashim, Daniel P.; Linhardt, Robert J.; Ajayan, Pulickel M. (2009-04-28). "Noncovalent Functionalization as an Alternative to Oxidative Acid Treatment of Single Wall Carbon Nanotubes with Applications for Polymer Composites". ACS Nano. 3 (4): 865–870. doi:10.1021/nn800860m.
  40. ↑ Yang, Wenrong; Thordarson, Pall; Gooding, J Justin; Ringer, Simon P; Braet, Filip (2007-10-17). "Carbon nanotubes for biological and biomedical applications". doi:10.1088/0957-4484/18/41/412001.
  41. ↑ Yang, Hui; Wang, Shiunchin C.; Mercier, Philippe; Akins, Daniel L. "Diameter-selective dispersion of single-walled carbon nanotubes using a water-soluble, biocompatible polymer". doi:10.1039/B515896F.
  42. ↑ Chen, Ran; Radic, Slaven; Choudhary, Poonam; Ledwell, Kimberley G.; Huang, George; Brown, Jared M.; Chun Ke, Pu (2012-09-24). "Formation and cell translocation of carbon nanotube-fibrinogen protein corona". Applied Physics Letters. 101 (13). doi:10.1063/1.4756794. PMC 3470598Freely accessible. PMID 23093808.
  43. ↑ Wang, Zhijuan; Li, Meiye; Zhang, Yuanjian; Yuan, Junhua; Shen, Yanfei; Niu, Li; Ivaska, Ari (2007-09-01). "Thionine-interlinked multi-walled carbon nanotube/gold nanoparticle composites". Carbon. 45 (10): 2111–2115. doi:10.1016/j.carbon.2007.05.018.
Wikimedia Commons has media related to Carbon nanotube functionalization.
This article is issued from Wikipedia - version of the 7/15/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.