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| [[File:GlassyCarbon.PNG|thumb|250px|A small rod of glassy carbon.]]
| | Myrtle Benny is how I'm called and I feel comfy when people use the complete name. I am a meter reader. One of the things he loves most is ice skating but he is struggling to discover time for it. South Dakota is exactly where me and my husband live.<br><br>Here is my website - [http://Corta.co/weightlossfoodprograms67803 Corta.co] |
| [[File:Vitreos carbon crucible 2.PNG|thumb|250px|vitreous-glassy carbon crucibles]]
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| '''Glass-like carbon''', often called '''glassy carbon''' or '''vitreous carbon''', is a non-graphitizing [[carbon]] which combines glassy and [[ceramic]] properties with those of [[graphite]]. The most important properties are high temperature resistance, hardness (7 [[Mohs scale of mineral hardness|Mohs]]), low density, low electrical resistance, low friction, low thermal resistance, extreme resistance to chemical attack and impermeability to gases and liquids. Glassy carbon is widely used as an electrode material in [[electrochemistry]], as well as for high temperature [[crucible]]s and as a component of some prosthetic devices, and can be fabricated as different shapes, sizes and sections.
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| The names ''glassy carbon'' and ''vitreous carbon'' have been introduced as trademarks; therefore, [[IUPAC]] does not recommend their use as technical terms.<ref name="iupac"/>
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| ==History==
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| It was first observed in the laboratories of The Carborundum Company, Manchester, UK, in the mid-1950s by Bernard Redfern, the inventor, a materials scientist and diamond technologist. He noticed that [[Sellotape]] he used to hold ceramic (rocket nozzle) samples in a furnace maintained a sort of structural identity after firing in an inert atmosphere.
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| He searched for a polymer matrix to mirror a diamond structure and discovered a resole resin that would, with special preparation, set without a catalyst. Using this phenolic resin, crucibles were produced. Crucibles were distributed to organisations such as UKAEA Harwell.
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| Redfern left The Carborundom Co., which officially wrote off all interests in the glassy carbon invention. Whilst working at [[Plessey|the Plessey Company]] laboratory (in a disused church) 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 Plessey Company set up a laboratory first in a factory previously used to make briar pipes, in Litchborough, UK, and then a permanent facility at Caswell, near Blakesly, UK. Caswell became the Plessey Research Centre and then the Allen Clark Research Centre. Glassy carbon arrived at the Plessey Company Limited as a fait accompli. Redfern was assigned J.C. Lewis, as a laboratory assistant, for the production of glassy carbon. F.C. Cowlard was assigned to Redfern's department later, as a laboratory administrator. Cowlard was an administrator who previously had some association with Silane (Silane US Patent assignee 3,155,621 3 Nov 1964). Neither he nor Lewis had any previous connection with glassy carbon.
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| Refern's contribution to the invention and production of glassy / Vitreous carbon is acknowledged by his co-authorship of early articles,.<ref>{{cite journal |last=Lewis |first=J.C. |coauthors=Redfern, B., Cowlard, F.C.|year=1963 |title=Vitreous carbon as a crucible material for semiconductors |journal=Solid-State Electronics |volume=6 |issue=3 |pages=251–254 |doi=10.1016/0038-1101(63)90081-9 |bibcode = 1963SSEle...6..251L }}</ref> But references to Redfern were not obvious in subsequent publications by Cowlard and Lewis.<ref>{{cite journal |last=Cowlard |first=F.C. |coauthors=Lewis, J.C. |year=1967 |title=Vitreous carbon — A new form of carbon |journal=Journal of Materials Science |volume=2 |issue=6 |pages=507–512 |doi=10.1007/BF00752216 |bibcode = 1967JMatS...2..507C }}</ref> Original boat crucibles and precursor samples exist.
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| UK patent application were filed in 11 Jan.1960 and US patent filed 9 Jan. 1961 (finalised as US patent 3,109,712). This prior art is not referenced in US 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 the son of Redfern.
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| 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.
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| Large sections of the precursor material were produced as castings, moldings 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 as the polymer, processed separately and subsequently give a perfect fit.
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| Some of the first ultrapure samples of Gallium Arsenide were zone refined in these crucibles. (Glassy carbon is extremely pure and unreactive to GaAs).
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| Doped/impure glassy carbon exhibited semiconductor phenomena.
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| Uranium carbide inclusions were fabricated (using U238 carbide at experimental scale).
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| On October 11, 2011, research conducted at the Carnegie Geophysical Laboratory led by Stanford’s Wendy L. Mao and her graduate student Yu Lin described a new form of glassy carbon formed under high pressure with hardness equal to diamond. Unlike diamond, however its structure is that of [[amorphous carbon]] so its hardness may be isotropic. Research is ongoing.<ref>[http://www.physorg.com/news/2011-10-superhard-carbon.html New form of superhard carbon observed]</ref>
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| ==Structure==
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| The structure of glassy carbon has long been a subject of debate. Early structural models assumed that both sp<sup>2</sup>- and sp<sup>3</sup>-bonded atoms were present, but it is now known that glassy carbon is 100% sp<sup>2</sup>. However, more recent research has suggested that glassy carbon has a [[fullerenes|fullerene]]-related structure.<ref>[http://www.personal.rdg.ac.uk/~scsharip/PM_glassy.pdf Fullerene-related structure of commercial glassy carbons], P.J.F. Harris, 2003.</ref>
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| Note that glassy carbon should not be confused with [[amorphous carbon]]. This from IUPAC: "Glass-like carbon cannot be described as amorphous carbon because it consists of two-dimensional structural elements and does not exhibit ‘dangling’ bonds."<ref name="iupac">[http://goldbook.iupac.org/G02639.html The entry for "Glass-like carbon" in IUPAC Goldbook.]</ref>
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| It exhibits a [[conchoidal fracture]].
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| ==Electrochemical properties==
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| Glassy carbon electrode (GCE) in aqueous solutions is considered to be an inert electrode for hydronium ion reduction:<ref name="Sawyer">{{cite book |first=D. T. |last=Sawyer |first2=A. |last2=Sobkowiak |first3=J. L., Jr. |last3=Roberts |title=Electrochemistry for Chemists |edition=Second |publisher=John Wiley & Sons |location=New York |year=1995 |isbn=0-471-59468-7 }}</ref>
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| :H<sub>3</sub>O<sup>+</sup><sub>(aq)</sub> + e<sup>-</sup> <math> \rm \stackrel{GCE} {\rightleftharpoons} </math> H<math>\cdot</math><sub>(aq)</sub> E<sup><s>o</s></sup> = −2.10 V versus [[standard hydrogen electrode|NHE]] at 25 °C
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| Comparable reaction on platinum:
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| :H<sub>3</sub>O<sup>+</sup><sub>(aq)</sub> + Pt<sub>(s)</sub> + e<sup>-</sup> <math> \rightleftharpoons </math> Pt:H<sub>(s)</sub> E<sup><s>o</s></sup> = 0.000 V versus NHE at 25 °C
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| The difference of 2.1 V is attributed to the properties of platinum which stabilizes a covalent Pt-H bond.<ref name="Sawyer"/>
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| == Advantages ==
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| Due to their specific surface orientation glassy carbon is employed as an electrode material for the fabrication of sensors. Glassy carbon paste, glassy carbon, carbon paste etc electrodes when modified are termed as chemically modified electrodes. Chemically modified electrodes have been employed for the analysis of organic molecules (viz., Paracetamol, aspirin, caffeine, phenol, catechol, resorcinol, hydroquinone, dopamine, L-dopa, epinephrine, nor epinephrine, methyl parathion, ethyl parathion, venlafaxine, desvenlafaxine, imipramine, trimipramine, desipramine etc) as well as metal ions (bismuth, antimony etc).<ref>{{cite journal|last=Sanghavi|first=Bankim|coauthors= Srivastava, Ashwini|title=Simultaneous voltammetric determination of acetaminophen, aspirin and caffeine using an in situ surfactant-modified multiwalled carbon nanotube paste electrode|journal=Electrochimica Acta|year=2010|volume=55|pages=8638–8648|doi=10.1016/j.electacta.2010.07.093|url=http://www.sciencedirect.com/science/article/pii/S0013468610010510}}</ref><ref>{{cite journal|last=Sanghavi|first=Bankim|coauthors=Mobin, Shaikh; Mathur, Pradeep; Lahiri, Goutam; Srivastava, Ashwini|title=Biomimetic sensor for certain catecholamines employing copper(II) complex and silver nanoparticle modified glassy carbon paste electrode|journal=Biosensors and Bioelectronics|year=2013|volume=39|pages=124–132|doi=10.1016/j.bios.2012.07.008|url=http://www.sciencedirect.com/science/article/pii/S0956566312004289}}</ref><ref>{{cite journal|last=Sanghavi|first=Bankim|coauthors=Srivastava, Ashwini|title=Simultaneous voltammetric determination of acetaminophen and tramadol using Dowex50wx2 and gold nanoparticles modified glassy carbon paste electrode|year=2011|volume=706|pages=246–254|doi=10.1016/j.aca.2011.08.040|url=http://www.sciencedirect.com/science/article/pii/S0003267011011706}}</ref> <ref>{{cite journal|last=Sanghavi|first=Bankim|coauthors=Srivastava, Ashwini|title=Adsorptive stripping differential pulse voltammetric determination of venlafaxine and desvenlafaxine employing Nafion–carbon nanotube composite glassy carbon electrode|journal=Electrochimica Acta|year=2011|volume=56|pages=4188–4196|doi=10.1016/j.electacta.2011.01.097|url=http://www.sciencedirect.com/science/article/pii/S001346861100171X}}</ref> <ref>{{cite journal|last=Sanghavi|first=Bankim|coauthors=Hirsch, Gary; Karna, Shashi; Srivastava, Ashwini|title=Potentiometric stripping analysis of methyl and ethyl parathion employing carbon nanoparticles and halloysite nanoclay modified carbon paste electrode|journal=Analytica Chimica Acta|year=2012|volume=735|pages=37–45|doi=10.1016/j.aca.2012.05.029|url=http://www.sciencedirect.com/science/article/pii/S0003267012007672}}</ref> <ref>{{cite journal|last=Mobin|first=Shaikh|coauthors=Sanghavi, Bankim; Srivastava, Ashwini; Mathur, Pradeep; Lahiri, Goutam|title=Biomimetic Sensor for Certain Phenols Employing a Copper(II) Complex|journal=Analytical Chemistry|year=2010|volume=82|pages=5983–5992|doi=10.1021/ac1004037|url=http://pubs.acs.org/doi/abs/10.1021/ac1004037}}</ref> <ref>{{cite journal|last=Gadhari|first=Nayan|coauthors=Sanghavi, Bankim; Srivastava, Ashwini|title=Potentiometric stripping analysis of antimony based on carbon paste electrode modified with hexathia crown ether and rice husk|journal=Analytica Chimica Acta|year=2011|volume=703|pages=31–40|doi=10.1016/j.aca.2011.07.017|url=http://www.sciencedirect.com/science/article/pii/S0003267011009585}}</ref> <ref>{{cite journal|last=Gadhari|first=Nayan|coauthors=Sanghavi, Bankim; Karna, Shashi; Srivastava, Ashwini|title=Potentiometric stripping analysis of bismuth based on carbon paste electrode modified with cryptand 2.2.1 and multiwalled carbon nanotubes|journal=Electrochimica Acta|year=2010|volume=56|pages=627–635|doi=10.1016/j.electacta.2010.09.100|url=http://www.sciencedirect.com/science/article/pii/S0013468610013599}}</ref> <ref>{{cite journal|last=Sanghavi|first=Bankim|coauthors=Srivastava, Ashwini|title=Adsorptive stripping voltammetric determination of imipramine, trimipramine and desipramine employing titanium dioxide nanoparticles and an Amberlite XAD-2 modified glassy carbon paste electrode|journal=Analyst|year=2013|doi=10.1039/C2AN36330E|url=http://pubs.rsc.org/en/Content/ArticleLanding/2013/AN/C2AN36330E|bibcode = 2013Ana...138.1395S }}</ref>
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| == See also ==
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| * [[Graphite]]
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| * [[Electrochemistry]]
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| * [[Fullerenes]]
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| ==References==
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| {{reflist}}
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| == External links ==
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| * [http://www.htw-gmbh.de HTW, supplier's website], for Glassy Carbon SIGRADUR
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| {{Allotropes of carbon}}
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| {{Carbon and its allotrophs}}
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| {{DEFAULTSORT:Glassy Carbon}}
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| [[Category:Carbon forms]]
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| [[Category:Amorphous solids]]
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Myrtle Benny is how I'm called and I feel comfy when people use the complete name. I am a meter reader. One of the things he loves most is ice skating but he is struggling to discover time for it. South Dakota is exactly where me and my husband live.
Here is my website - Corta.co