Glassy carbon

Glass-like carbon,often calledglassy carbonorvitreous carbon,is anon-graphitizing,or nongraphitizable,carbonwhich combines glassy andceramicproperties with those ofgraphite.The most important properties are high thermal stability, high thermal conductivity, hardness (7Mohs), low density, low electrical resistance, low friction, extreme resistance to chemical attack, and impermeability to gases and liquids. Glassy carbon is widely used as an electrode material inelectrochemistry,for high-temperaturecrucibles,and as a component of some prosthetic devices. It can be fabricated in different shapes, sizes and sections.

The namesglassy carbonandvitreous carbonhave been registered as trademarks, andIUPACdoes not recommend their use as technical terms.^[1]

A historical review of glassy carbon was published in 2021.^[2]

History

Glassy carbon was first observed in the laboratories of The Carborundum Company, Manchester, UK, in the mid-1950s by Bernard Redfern, a materials scientist and diamond technologist. He noticed thatSellotapehe used to hold ceramic (rocket nozzle) samples to the floor of a furnace transformed "into an unusual structure that preserved its original form" after firing in an inert atmosphere.^[3]He searched for a polymer matrix to mirror a diamond structure and discovered aresoleresin that would, with special preparation, set without a catalyst. Crucibles were produced with this phenolic resin, and distributed to organisations such asUKAEAHarwell.

Redfern left The Carborundum Co., which officially wrote off all interests in the glassy carbon invention. While working at thePlessey Companylaboratory in Towcester, UK, Redfern received a glassy carbon crucible for duplication from UKAEA. He identified it as one he had made from markings he had engraved into the uncured precursor prior to carbonisation—it is almost impossible to engrave the finished product. The company set up a laboratory in Litchborough, and then a permanent facility at Caswell, Northamptonshire, which becamePlessey Research Caswelland then theAllen Clark Research Centre.

Glassy carbon arrived at the Plessey as afait accompli.The contribution of Redfern to the invention and production of glassy/vitreous carbon is acknowledged by his co-authorship of early articles,^[4]but references to him were not obvious in subsequent publications by Cowlard and Lewis.^[5]Original boat crucibles, thick section rods and precursor samples exist.

Redfern's British patent application were filed on 11 January 1960 and he was the author of U.S. patent 3109712A, granted 5 November 1963, priority date 11 January 1960, filing date 9 January 1961.^[6]This came after the rescinded British patent. This prior art is not referenced in U.S. patent 4,668,496, 26 May 1987 for Vitreous Carbon. Patents were filed "Bodies and shapes of carbonaceous materials and processes for their production" and the name "Vitreous Carbon" presented to the product by Redfern's son.

Glassy/vitreous carbon was under investigation used for components for thermonuclear detonation systems and at least some of the patents surrounding the material were rescinded (in the interests of national security) in the 1960s.

Large sections of the precursor material were produced as castings, mouldings or machined into a predetermined shape. Large crucibles and other forms were manufactured.

Carbonisation took place in two stages. Shrinkage during this process is considerable (48.8%) but is absolutely uniform and predictable. A nut and bolt can be made to fit while in polymer form, processed separately but identically, and subsequently give a perfect fit.

Some of the first ultra-pure samples ofgallium arsenide(GaAs) were zone refined in these crucibles (glassy carbon is not reactive with GaAs).

Doped/impure glassy carbon exhibitssemiconductorphenomena.

Vitreous carbon was fabricated withuranium carbideinclusions, on experimental scale, usingUranium 238.

On 11 October 2011, research conducted at theCarnegie Geophysical Laboratoryled byWendy L. MaofromStanford,and her graduate student Yu Lin, described a new form of glassy carbon formed under high pressure, with hardness equal to diamond – a kind ofdiamond-like carbon.Unlike diamond, however its structure is that ofamorphous carbonso its hardness may be isotropic. Research was ongoing as of 2011^[update].^[7]

Reticulated vitreous carbon

Vitreous carbon can also be produced as a foam, calledreticulatedvitreous carbon(RVC). This foam was first developed in the mid to late 1960s as a thermally insulating, microporous glassy carbon electrode material. RVC foam is a strong, inert, electrically and thermally conductive, and corrosion-resistant porous form of carbon with a low resistance to gas and fluid flow. Due to these characteristics, the most widespread use of RVC in scientific work is as a three-dimensional electrode in electrochemistry.^[8]Additionally, RVC foams are characterized by an exceptionally high void volume, high surface area, and very high thermal resistance in non-oxidising environments, which allows for heat sterilization and facilitates manipulation in biological applications.

Structure

The structure of glassy carbon has long been a subject of debate.

Early structural models assumed that bothsp²- and sp³-bondedatoms were present, but it is now known that glassy carbon is 100% sp².More recent research has suggested that glassy carbon has afullerene-related structure.^[9]

It exhibits aconchoidal fracture.

Note that glassy carbon should not be confused withamorphous carbon.This fromIUPAC:

"Glass-like carbon cannot be described asamorphous carbonbecause it consists of two-dimensional structural elements and does not exhibit 'dangling' bonds. "^[1]

Electrochemical properties

Glassy carbon electrode (GCE) in aqueous solutions is considered to be an inert electrode forhydroniumion reduction:^[10]

{\ce {{\overset {hydronium}{H3O+_{(aq)}}}+ e^- <=>[{\ce {GCE}}] H._{(aq)}}}

E^{\ominus }=-2.10\ \mathrm {V}

versusNHEat 25 °C

Comparable reaction on platinum:

{\ce {H3O+_{(aq)}{}+ Pt_{(s)}+ e^- <=> Pt:H_{(s)}}}

E^{\ominus }=\ 0.000\ \mathrm {V}

versus NHE at 25 °C

The difference of 2.1 V is attributed to the properties of platinum which stabilizes a covalent Pt-H bond.^[10]

Physical properties

Properties include 'high temperature resistance', hardness (7 Mohs), low density, low electrical resistance, low friction, and low thermal resistance.^{[citation needed]}

Applications

Due to its specific surface orientation, glassy carbon is employed as an electrode material for the fabrication of sensors. Carbon paste, glassy carbon paste, glassy carbon etc. electrodes when modified are termed chemically modified electrodes.^[11]Vitreous carbon and carbon/carbon fibre composites are used for dental implants and heart valves because of their bio-compatibility, stability and simple manufacturing techniques.

References

^^a ^b McNaught, A.D.; Wilkinson, A.; Chalk, S.J., eds. (2019) [1997]."Glass-like carbon".Compendium of Chemical Terminology (the "Gold Book" ) (Report) (2nd, online ed.).International Union of Pure and Applied Chemistry.doi:10.1351/goldbook.ISBN 978-0-9678550-9-7.
^Uskoković, Vuk (2021)."A historical review of glassy carbon: Synthesis, structure, properties and applications".Carbon Trends.5:100116.Bibcode:2021CarbT...500116U.doi:10.1016/j.cartre.2021.100116.S2CID 241718868.
^Uskoković, Vuk (2021)."A historical review of glassy carbon: Synthesis, structure, properties and applications".Carbon Trends.5:100116.Bibcode:2021CarbT...500116U.doi:10.1016/j.cartre.2021.100116.S2CID 241718868.
^ Lewis, J.C.; Redfern, B.; Cowlard, F.C. (1963). "Vitreous carbon as a crucible material for semiconductors".Solid-State Electronics.6(3): 251–254.Bibcode:1963SSEle...6..251L.doi:10.1016/0038-1101(63)90081-9.
^ Cowlard, F.C.; Lewis, J.C. (1967). "Vitreous carbon — a new form of carbon".Journal of Materials Science.2(6): 507–512.Bibcode:1967JMatS...2..507C.doi:10.1007/BF00752216.S2CID 135763145.
^"U.S. Patent 3109712"– via Google Patents.
^"New form of superhard carbon observed".physorg.com.October 2011.
^Walsh, F.C.; Arenas, L.F.; Ponce de León, C.; Reade, G.W.; Whyte, I.; Mellor, B.G. (2016)."The continued development of reticulated vitreous carbon as a versatile electrode material: Structure, properties and applications"(PDF).Electrochimica Acta.215:566–591.doi:10.1016/j.electacta.2016.08.103.
^ Harris, P.J.F. (2003)."Fullerene-related structure of commercial glassy carbons"(PDF).Philosophical Magazine.Series 8.84(29): 3159–3167.Bibcode:2004PMag...84.3159H.CiteSeerX10.1.1.359.5715.doi:10.1080/14786430410001720363.S2CID 220342075.
^^a ^bSawyer, D. T.; Sobkowiak, A.; Roberts, J. L. Jr. (1995).Electrochemistry for Chemists(Second ed.). New York: John Wiley & Sons.ISBN 978-0-471-59468-0.
^Sanghavi, Bankim; Srivastava, Ashwini (2010). "Simultaneous voltammetric determination of acetaminophen, aspirin and caffeine using an in situ surfactant-modified multiwalled carbon nanotube paste electrode".Electrochimica Acta.55(28): 8638–8648.doi:10.1016/j.electacta.2010.07.093.

External links

HTW, supplier's website,for Glassy Carbon SIGRADUR

[iupac-1] McNaught, A.D.; Wilkinson, A.; Chalk, S.J., eds. (2019) [1997]."Glass-like carbon".Compendium of Chemical Terminology (the "Gold Book" ) (Report) (2nd, online ed.).International Union of Pure and Applied Chemistry.doi:10.1351/goldbook.ISBN 978-0-9678550-9-7.

[2] Uskoković, Vuk (2021)."A historical review of glassy carbon: Synthesis, structure, properties and applications".Carbon Trends.5:100116.Bibcode:2021CarbT...500116U.doi:10.1016/j.cartre.2021.100116.S2CID 241718868.

[3] Uskoković, Vuk (2021)."A historical review of glassy carbon: Synthesis, structure, properties and applications".Carbon Trends.5:100116.Bibcode:2021CarbT...500116U.doi:10.1016/j.cartre.2021.100116.S2CID 241718868.

[4] Lewis, J.C.; Redfern, B.; Cowlard, F.C. (1963). "Vitreous carbon as a crucible material for semiconductors".Solid-State Electronics.6(3): 251–254.Bibcode:1963SSEle...6..251L.doi:10.1016/0038-1101(63)90081-9.

[5] Cowlard, F.C.; Lewis, J.C. (1967). "Vitreous carbon — a new form of carbon".Journal of Materials Science.2(6): 507–512.Bibcode:1967JMatS...2..507C.doi:10.1007/BF00752216.S2CID 135763145.

[6] "U.S. Patent 3109712"– via Google Patents.

[7] "New form of superhard carbon observed".physorg.com.October 2011.

[8] Walsh, F.C.; Arenas, L.F.; Ponce de León, C.; Reade, G.W.; Whyte, I.; Mellor, B.G. (2016)."The continued development of reticulated vitreous carbon as a versatile electrode material: Structure, properties and applications"(PDF).Electrochimica Acta.215:566–591.doi:10.1016/j.electacta.2016.08.103.

[9] Harris, P.J.F. (2003)."Fullerene-related structure of commercial glassy carbons"(PDF).Philosophical Magazine.Series 8.84(29): 3159–3167.Bibcode:2004PMag...84.3159H.CiteSeerX10.1.1.359.5715.doi:10.1080/14786430410001720363.S2CID 220342075.

[Sawyer-10] Sawyer, D. T.; Sobkowiak, A.; Roberts, J. L. Jr. (1995).Electrochemistry for Chemists(Second ed.). New York: John Wiley & Sons.ISBN 978-0-471-59468-0.

[11] Sanghavi, Bankim; Srivastava, Ashwini (2010). "Simultaneous voltammetric determination of acetaminophen, aspirin and caffeine using an in situ surfactant-modified multiwalled carbon nanotube paste electrode".Electrochimica Acta.55(28): 8638–8648.doi:10.1016/j.electacta.2010.07.093.

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v t e Allotropes of carbon
sp³forms	Diamond (cubic) Lonsdaleite (hexagonal diamond)
sp²forms	Graphite Graphene Fullerenes,includingC₆₀(buckminsterfullerene),C₇₀,Fullerene whiskers,Nanotubes,Nanobuds,Nanoscrolls) Glassy carbon
sp forms	Linear acetylenic carbon C ₆(cyclo[6]carbon) C ₁₈(cyclo[18]carbon)
mixed sp³/sp²forms	Amorphous carbon Carbon nanofoam Carbide-derived carbon Q-carbon
other forms	C ₁(atomic carbon) C ₂(diatomic carbon) C ₃(tricarbon)
hypothetical forms	C ₃(cyclopropatriene) C ₆(prismane C8) Chaoite Haeckelites Cubic carbon Metallic carbon Penta-graphene
related	Activated carbon Carbon black Charcoal Carbon fiber Aggregated diamond nanorod