Composites Design and Manufacture (Plymouth University teaching support materials)
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Nanotechnology is an enormous subject.  For a comprehensive introduction see, for example, [1-3].  This page specifically addresses nanoscale composite materials and related structures.  Al-Quraishi et al [4] have reviewed the experimental techniques developed for the mechanical testing of two-dimensional materials.

  1. GA Ozin and A Arsenault, Nanochemistry, A Chemical Approach to Nanomaterials, Royal Society of Chemistry, Cambridge, 2005. ISBN 0-85404-664-x.  PU CSH Library.
  2. SC Tjong, Nanocrystalline Materials, Their Synthesis-Structure-Property Relationships and Applications, Elsevier, 2006. ISBN 0-08-044697-3.
  3. WK Liu, EG Karpov and HS Park, Nano Mechanics and Materials, Wiley, 2006. ISBN-13: 978-0-470-01851-4.
  4. KK Al-Quraishi, Q He, W Kauppila, Min Wang and Y Yang, Mechanical testing of two-dimensional materials: a brief review, International Journal of Smart and Nano Materials, 2020, 11(3), 207-246.


It is normal in engineering to use decimal prefixes to denote small or large numbers which differ from the SI standard measurement by a factor of one or more thousands (see Table 1 to the right).  So if we use this prefix in the context of length, the basic unit is the metre, and hence nanotechnology refers to a length scale of the order of one-millionth of a millimetre.  An alternative reference point is the atomic nature of materials: Evans [1] gives a figure of 0.532Å (0.0532 nm) for the radius of the inner electron orbital (principal quantum number, n, is 1) in the Rutherford-Bohr model for the hydrogen atom and 2.128 (0.2128 nm) when n is 2.

The International Organisation for Standards (ISO) has described a “nano-tree” [2] for the categorisation of a wide ranges of nanomaterials, including nano-objects, nanostructures and nanocomposites of various dimensionality of different physical, chemical, magnetic and biological properties.  The Institute of Nanotechnology (IoN) has published a glossary of nanotechnology terms [3].

  1. RC Evans, An Introduction to Crystal Chemistry - second edition, Cambridge University Press, Cambridge, 1966.
  2. ISO/TR 11360:2010: Nanotechnologies - methodology for the classification and categorization of nanomaterials
  3. Glossary of Terms (Institute of Nanotechnology)
Table 1
x 10-x 10+x
3 milli- (m) kilo- (k)*
6 micro- (μ) mega- (M)
9 nano- (n) giga- (G)
12 pico- (p) tera- (T)
15 femto- (f) peta- (P)
18 atto- (a) exa- (E)
* note that capital K is used, mainly in computing,
to represent 210 or 1024, while k is 1000.

Carbon allotropes and nanotubes

Elemental carbon can occur in an amorphous form or as either of two crystalline forms:

The carbon atom can also combine to form spheres and/or tubes at the nanoscale.  These structures include the Carbon 60 form known as buckminsterfullerene (named after the geodesic structures of Buckminster Fuller) discovered by Harry Kroto, Bob Curl and Rick Smalley in 1985 [1-3] which won them the Nobel Prize in Chemistry for 1996 [4].  James P Birk has presented a stereoscopic image of the C60 "bucky ball", while Jianyu Huang at Sandia National laboratories and Boris Yakobson at Rice University have used electron microscope video and computer simulations (YouTube Shrink Wrap buckyball video) show that buckyballs start life as distorted, unstable sheets of graphite which shed loosely connected threads and chains until all that remains is the perfectly spherical buckyball.

Iijima [5] discovered long, thin carbon nanotubes in 1991.  The topic was recently reviewed by Terrones [6].  The Iijima nanotubes were considered to be elongated fullerenes consisting of concentric graphene cylinders (multi-walled carbon nanotubes (MWNTs) with interlayer spacings slightly greater than that of graphite at 3.4Å.  Single-walled carbon nanotubes (SWNTs) have also been isolated.  The molecular configurations of SWNTs include "zigzag" (edges of the benzene rings running parallel to the tube axis), "armchair" (edges of the benzene rings running perpendicular to the tube axis) and "chiral" where the edges of the benzene ring follow a spiral path along the tube.

Terrones [6] suggests that optimal conditions for the arc discharge production of nanotubes involve passing a 80-100 amp DC current through high purity graphite electrodes (6-10 mm outer diameter at ~1-2 mm apart in a low pressure (500 torr) helium atmosphere.  A combination of carbon MWNTs and nested polyhedral graphite is deposited on the cathode at 1 mm/min while the anode is consumed.  Alternative production techniques [6] include:

These production methods produce MWNTs and polyhedral particles from which they must be separated.  This might be achieved by oxidation at 700°C (<5% yield), filtering colloidal suspensions, ultrasonically assisted microfiltration or microwave heating together with acid treatments to remove residual metals.

Researchers at Cambridge University have produced live videos showing the nucleation and growth by chemical vapour deposition (CVD) of carbon nanofibres and nanotubes at minute particles of nickel catalyst.  The movies offer greater insight into the self-assembly of the microscopic structures.  The CVD process uses acetylene gas to deposit minute crystalline droplets referred to as "catalyst islands" (the nickel).  In nanofibre production, the catalyst was gradually squeezed upwards as carbon formed around it.  In single-walled nanotube production, the application of gas was reduced so that the carbon lifted off the catalyst to form a tubular structure.

Table 2:  The measured axial Youngs moduli and strengths of carbon nanotubes
 Nanotube  Measured by  Young's modulus (GPa)  Strength (GPa)  Reference
SWNT   320-1470 (mean = 1002) 13-52 (mean = 30) 7  (Yu et al)
SWNT   ~1000 75 8  (Lu)
 MWNT  Thermal vibration inside TEM  1000-1800   9  (Treacy et al)
 MWNT  Flexure of tubules in AFM  ~1280   10  (Wong et al)
MWNT In-situ in SEM 800-900 150 11  (Demczyk et al)
MWNT   ~1000 150 8  (Lu)

Fan et al [12] have produced a new atomically thin material, biphenylene networks, by assembling carbon-containing molecules on an extremely smooth gold surface. The molecules first form chains of linked hexagons, then a further reaction connects the chains together to form a regular array of squares and octagons.  the biphenylene network exists in two chiral (mirror) forms.

Tibbets et al [13] have reviewed the fabrication and properties of vapour-grown carbon nanofiber/polymer composites.  Gibson et al [14] have reviewed the vibration of carbon nanotubes and their composites.  The paper considers modelling and simulation of vibrating nanotubes, studies of nanomechanical resonators and oscillators, characterisation of nanotube mechanical properties, augmentation of the dynamic structural properties of composites, nanotube-based sensors and actuators, use of ultrasound to disperse the tubes in liquids (sonication), Raman scattering and interactions with high frequencies.

An important consideration in generating high-quality nano-particle reinforced composites is obtaining a uniform distribution of reinforcement rather than agglomerated (clumped) particles. Dassios et al [15] have sought to achieve this by sonication.

Poland et al [16] considered the similarities between the needle-like shape of carbon nanotubes and asbestos. They exposed the mesothelial lining of the body cavity of mice, as a surrogate for the mesothelial lining of the chest cavity, to long multiwalled carbon nanotubes. Asbestos-like, length-dependent, pathogenic behaviour included inflammation and the formation of lesions known as granulomas. On the basis of their results, they suggest there is a "need for further research and great caution before introducing such products into the market if long-term harm is to be avoided".

References for carbon allotropes and nanotubes

  1. HW Kroto, JR Heath, SC O'Brien, RF Curl and RE Smalley, C60: Buckminsterfullerene, Nature, 1985, 318(6042), 162-163.
  2. HW Kroto, Space, Stars, C60 and Soot, Science, 1988, 242(4882), 1139-1145.
  3. HW Kroto, C60: Buckminsterfullerene, the Celestial Sphere that Fell to Earth, Angewandte Chemie, 1992, 31(2), 111-129.
  4. The Nobel Prize in Chemistry 1996, 9 October 1996
  5. S Iijima, Helical microtubules of graphitic carbon, Nature, 7 November 1991, 354(6348), 56-58.
  6. M. Terrones, Carbon nanotubes: synthesis and properties, electronic devices and other emerging applications, International Materials Reviews, 2004, 49(6), 325-377.
  7. MF Yu, BS Files, S Arepalli and RS Ruoff, Tensile loading of ropes of single wall carbon nanotubes and their mechanical properties, Physics Review Letters, 12 June 2000, 84(24), 5552-5555.
  8. JP Lu, Elastic properties of carbon nanotubes and nanoropes, Physical Review Letters, 1997, 79(7), 1297-1300.
  9. MMJ Treacy, TW Ebbesen and JM Gibson, Exceptionally high Young's modulus observed for individual carbon nanotubes, Nature, 20 June 1996, 381(6584), 678-680.
  10. EW Wong, PE Sheehan and CM Lieber, Nanobeam mechanics: elasticity, strength, and toughness of nanorods and nanotubes, Science, 26 September 1997,  277(5334), 1971-1975.
  11. BG Demczyk, YM Wang, J Cumings, M Hetman, W Han, A Zettl and RO Ritchie, Direct mechanical measurement of the tensile strength and elastic modulus of multiwalled carbon nanotubes, Materials Science and Engineering: A, 1 September 2002, 334(1–2), 173–178.
  12. QT Fan, LH Yan, MW Tripp, O Krejči, S Dimosthenous, SR Kachel, MY Chen, AS Foster, U Koert, P Liljeroth and JM Gottfried, Biphenylene network: a nonbenzenoid carbon allotrope, Science, 2021, 372(6544), 852-856.
  13. GG Tibbetts, ML Lake, KL Strong and BP Rice, A review of the fabrication and properties of vapor-grown carbon nanofiber/polymer composites, Composites Science and Technology, June 2007, 67(7-8), 1709-1718.
  14. RF Gibson, EO Ayorinde and Y-F Wen, Vibrations of carbon nanotubes and their composites: a review, Composites Science and Technology, 2007, 67(1), 1-28.
  15. KG Dassios, P Alafogianni, SK Antiohos, C Leptokaridis, N-M Barkoula and TE Matikas, Optimization of sonication parameters for homogeneous surfactant-assisted dispersion of multiwalled carbon nanotubes in aqueous solutions, The Journal of Physical Chemistry C, 2015, 119(13), 7506-7516.
  16. CA Poland, R Duffin, I Kinloch, A Maynard, WAH Wallace, A Seaton, V Stone, S Brown, W MacNee and K Donaldson, Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity in a pilot study, Nature Nanotechnology, July 2008, 3(7), 423-428.

Other resources for carbon allotropes and nanotubes

Two-dimensional monolayers

References for two-dimensional monolayers

  1. Manchester Graphene, Graphene is going to revolutionize the 21st Century, accessed 11:34 on Saturday 18 January 2014.
  2. M Kemp, Graphene - a perspective, Materials World, October 2015, 23(10), 46-47.
  3. C Soutis, Graphene webinar Q&A, private communication, 28 September 2020.
  4. J-X Shi, T Natsuki, X-W Lei and Q-Q Ni, Equivalent Young's modulus and thickness of graphene sheets for the continuum mechanical models, Applied Physics Letters, 2014, 104(22), 223101.
  5. S Zhang, J Zhou, Q Wang, X Chen, Y Kawazoe and P Jena, Penta-graphene: a new carbon allotrope, Proceedings of the National Academy of Sciences of the United States of America (PNAS), direct submission published online 02 February 2015. Supplementary material.
  6. N Koratkar, Graphene in Composite Materials: synthesis, characterization and applications, DEStech Publications, Lancaster PA, 2013.  ISBN 978-1-60595-056-3.
  7. Qing Peng, AK Dearden, J Crean, L Han, S Liu, X Wen and S De, New materials graphyne, graphdiyne, graphone, and graphane: review of properties, synthesis, and application in nanotechnology, Nanotechnology, Science and Applications, 10 April 2014, 7, 1-29.
  8. Y Gao, T Cao, F Cellini, C Berger, WA de Heer, E Tosatti, E Riedo and A Bongiorno, Ultrahard carbon film from epitaxial two-layer graphene, Nature Nanotechnology, 2017.
  9. Ellis Davies, Tough as diamond, Materials World, February 2018, 26(2), 18.
  10. Y Hu, C Wu, Q Pan, Y Jin, R Lyu, V Martinez, S Huang, J Wu, LJ Wayment, NA Clark, MB Raschke, Y Zhao and W Zhang, Synthesis of γ-graphyne using dynamic covalent chemistry, Nature Synthesis, 2022.
  11. LA Burchfield, M Al Fahim, RS Wittman, F Delodovici, N Manini, Novamene: a new class of carbon allotropes, Materials Science ~ Chemistry, 7 Feb 2017, 3(2), e00242.
  12. A Acun, B Poelsema, HJW Zandvliet and R van Gastel1, The instability of silicene on Ag(111), Applied Physics Letters, 2013, 103, 263119.
  13. Silicene – a one-atom-thick layer of silicon – is tipped to be graphene’s main contender. But recent research has shown that producing it may be far trickier than initially thought, Materials KTN, accessed 10:50 on Saturday 18 January 2014.
  14. Wonder material silicene has suicidal tendencies; UT researches demonstrate that graphene 2.0 can barely be made, University of Twente, 08 January 2014, accessed 10:50 on Saturday 18 January 2014.
  15. D Johnson, New germanium-based material could replace silicon for electronics, IEEE Spectrum, 11 April 2013.
  16. Will 2-D tin be the next super material? Theorists predict new single-layer material could go beyond graphene, conducting electricity with 100% efficiency at room temperature, Stanford SLAC National Accelerator Laboratory, 21 November 2013.
  17. Y Guo, Y-F Zhang, X-Y Bao, T-Z Han, Z Tang, L-X Zhang, W-G Zhu, EG Wang, Q Niu, ZQ Qiu, J-F Jia, Z-X Zhao and Q-K Xue, Superconductivity modulated by quantum size effects, Science, 10 December 2004, 306(5703), 1915-1917.
  18. H Zhao, C-w Zhang, W-x Ji, R-w Zhang, S-s Li, S-s Yan, B-m Zhang, P Li and P-j Wang, Unexpected giant-gap Quantum Spin Hall insulator in chemically decorated plumbene monolayer, Scientific Reports, 02 February 2016, 6, 20152.
  19. K Allen, Borophene's unlocked potential, Materials World, Apriil 2017, 25(4), 3.
  20. AJ Mannix, X-F Zhou, B Kiraly, JD Wood, D Alducin, BD Myers, X Liu, BL Fisher, U Santiago, JR Guest, MJ Yacaman, A Ponce, AR Oganov, MC Hersam and NP Guisinger, Synthesis of borophenes: Anisotropic, two-dimensional boron polymorphs," Science, 18 December 2015, 350(6267), 1513-1516.
  21. S Frost, Step aside for boron nitride, Materials World, February 2016, 24(2), 12-14.
  22. S Frost, Bridging the band gap, Materials World, October 2015, 23(10), 18-19.
  23. N Daniels, The tiny promise of phosphorene, Materials World, June 2016, 24(6), 21.

Vegetable fibres

David Hepworth and Eric Whale founded a company, CelluComp (Burntisland, Fife, Scotland), to utilise Curran® nanofibres extracted from vegetables.  Their initial material choices were carrot and sugarbeet although turnips, swede (rutabagas) and parsnips we also expected to provide raw materials.  The fibres were claimed to have a modulus of 130 GPa, strengths up to 5 GPa and failure strains of over 5%.  The company's first product was the "Just Cast" fly-fishing rod.

Siqueira et al [3] have separated nanofibres from carrot juice and demonstrated their reinforcing efficiency in cellulose acetate butyrate (CAB) to be in the range 79-88%.

References for vegetable fibres
  1. Donald Houston, Root of strength and innovation, 09 February 2007.
  2. The future is orange for hi-tech material made from carrots, Guardian Unlimited, 09 February 2007.
  3. G Siqueira, K Oksman, SK Tadokoro and AP Mathew, Re-dispersible carrot nanofibers with high mechanical properties and reinforcing capacity for use in composite materials, Composites Science and Technology, 8 February 2016, 123, 49-56.

Bacterial cellulose (BC)

Exfoliated clays

Many clays are layered inorganic compounds which can be delaminated (normally referred to as exfoliated in this context). These materials have potential as precursors for the development of various nanostructures.  The most common smectite clays used for nanocomposites are montmorillonite [1], saponite and hectorite.  The montmorillonite nanoclay [2] has a plate structure with a thickness of one nanometre or less (a few atoms) and an aspect ratio of 1000:1 (hence a plate edge of ~ 1 μm) [with potential implications for health and safety].  Relatively low levels of clay loading are claimed to improve modulus, flexural strength, heat distortion temperature, barrier properties etc without compromising impact and clarity [2].

Maniar [2] identifies the first patent in this area as Carter et al (1950) [3] and the second as assigned to Unitka Limited in 1976 [4] with the market debut of a montmorillonite/polyamide-6 nanocomposite in 1989.

References for exfoliated clays
  1. JN Hay and SJ Shaw, Clay-Based Nanocomposites (AZoM)
  2. KK Maniar, Polymeric nanocomposites: a review, Polymer-Plastics Technology and Engineering, 2004, 43(2), 427-443 [103 references].
  3. W Carter Lawrence, G Hendriks John and DS Bolley, Elastomer reinforced with a modified clay, United States Patent 2 531 396, 1950.
  4. Unitka, Japanese Patent 109 998 , 1976 (no further detail in [2]).

Fluid bicontinuous gels

Colloidal particles (nanoparticles) can have equal affinity for two fluids and hence adsorb irreversibly to the fluid-fluid interface. Stratford et al have presented computer simulations of a pair of solvents containing such particles where the new interface formed on demixing sequesters the colloidal particles.  Interfacial tension forces the particles into close contact and the interface coarsens then is curtailed.  The jammed colloidal layer appears to enter a glassy state with a multiply connected, solid-like film in three dimensions. The resulting gel contains inter-penetrating domains of each fluid.

References for fluid bicontinuous gels
  1. Philippe Poulin, New gels for mixing immiscible liquids, Science, 30 September 2005, 309(5744), 2174 - 2175 (Plymouth shelfmark 500SCI - not available in UoP electronic resources).
  2. K Stratford, R Adhikari, I Pagonabarraga, J-C Desplat and ME Cates, Colloidal jamming at interfaces: a route to fluid-bicontinuous gels, Science, 30 September 2005, 309(5744), 2198 - 2201 (Plymouth shelfmark 500SCI - not available in UoP electronic resources) Supporting Online Material  Movie S1  Movie S2  Movie S3.

Porous liquids

Giri et al [1] have reported free-flowing liquids with bulk properties determined by their permanent porosity.  These "porous liquids" have cage molecules that are highly soluble in solvents and have well-defined pore space which the solvent molecules are too large to penetrate.  Zhang et al [2] suggested that the liquid-like polymeric matrices may be used as separation media and the empty cavities as gas transport pathway allowing the porous liquid to function as a promising candidate for gas separation.  Zhang et al [3] have presented a minireview of recent advances in the design of porous ionic liquids, including the synthesis of ordered and disordered porous ionic liquid-based nanoparticles or membranes with or without templates, together with potential for room temperature porous ionic liquids.

References for porous liquids
  1. N Giri, MG Del Pópolo, G Melaugh, RL Greenaway, K Rätzke, T Koschine, L Pison, MF Costa Gomes, AI Cooper and SL James, Liquids with permanent porosity, Nature, 12 November 2015, 527, 216–220.
  2. J Zhang, S-H Chai, Z-A Qiao, SM Mahurin, J Chen, Y Fang, S Wan, K Nelson, P Zhang and S Dai, Porous Liquids: a promising class of media for gas separation, Angewandte Chemie International Edition, first published 17 November 2014.
  3. S Zhang, K Dokkoa and M Watanabe, Porous ionic liquids: synthesis and application, Chemical Science, 2015, 6(7), 3684-3691.


Nanocemology [1] is the science of ultra-fine, micro- and nano-scale mechanisms occurring in, and affecting the performance of microscopic constituent materials and the pore structure of cement and concrete.  The Nanocem Marie Curie Research Training Network [2] aims to develop ultra-high-strength concrete of low permeability, high tensile strength whose density will be sufficient to secure high abrasion and chemical resistance.

References for nanocemology
  1. D Ball, Nanocemology - the key to the future, Concrete, February 2007, 41(1), 29-30.
  2. Nanocem Marie Curie Research Training Network

Nanotechnology probes

URLs for Atomic Force Microscope (AFM)
URLs for Scanning tunnelling microscope (STM)
URLs for Superconducting Quantum Interference Devices (SQUID)

URLs for nanotechnology

Further reading (most recent first)

  1. Ignac Capek, Nanocomposite structures and dispersions, Elsevier, 2006. ISBN 0-444-52716-8.
  2. EPS Tan and CT Lim, Mechanical characterization of nanofibers: a review, Composites Science and Technology, 2006, 66(9), 1102-1108. ISSN 0266-3538.
  3. K-t Lau, C Gu and D Hui, A critical review on nanotube and nanotube/nanoclay related polymer composite materials, Composites Part B: Engineering, 2006, 37(6), 425-436.
  4. ET Thostenson, C Li and T-W Chou, Nanocomposites in context, Composites Science and Technology, 2005, 65(3-4), 491-516.
  5. R Murugan and S Ramakrishna, Development of nanocomposites for bone grafting, Composites Science and Technology, 2005, 65(15-16), 2385-2406.
  6. Ludwik Leibler, Nanostructured plastics: Joys of self-assembling, Progress in Polymer Science, 2005, 30(8-9), 898-914.
  7. C Wang, Z-X Guo, S Fu, W Wu and D Zhu, Polymers containing fullerene or carbon nanotube structures, Progress in Polymer Science, 2004, 29(11), 1079-1141.
  8. Z-M Huang, Y-Z Zhang, M Kotaki and S Ramakrishna, A review on polymer nanofibers by electrospinning and their applications in nanocomposites, Composites Science and Technology, 2003, 63(15), 2223-2253.
  9. SS Ray and M Okamoto, Polymer/layered silicate nanocomposites: a review from preparation to processing, Progress in Polymer Science, 2003, 28(11), 1539-1641.
  10. T Liu, C Burger and B Chu, Nanofabrication in polymer matrices, Progress in Polymer Science, 2003, 28(1), 5-26.
  11. K Ishizu, K Tsubaki, A Mori and S Uchida, Architecture of nanostructured polymers, Progress in Polymer Science, 2003, 28(1), 27-54.
  12. ET Thostenson, Z Ren and T-W Chou, Advances in the science and technology of carbon nanotubes and their composites: a review, Composites Science and Technology, 2001, 61(13), 1899-1912.

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Created by John Summerscales on 07 August 2006 and updated on 30-May-2022 16:28. Terms and conditions. Errors and omissions. Corrections.