- Email: [email protected]
Easy deposition of amorphous carbon films on glass substrates
CARBON
1801
4 6 ( 20 0 8 ) 1 7 9 2–18 2 8
ume fraction and electrical resistivity is much lower than those in prior related work at the same carbonization temperature. Although any of the fillers diminished the scratch resistance of the carbon film, carbon film including nickel showed higher scratch resistance than carbon film including the MWCNT at a similar filler volume fraction.
Acknowledgement Partial support of this work by the Mark Diamond Research Fund, University at Buffalo, State University of New York, is hereby acknowledged.
R E F E R E N C E S
[1] Yamada Y, Chung DDL. Three-dimensional microstructuring of carbon by thermoplastic spacer evaporation during pyrolysis. Carbon, in press, doi:10.1016/j.carbon.2008.07.031. [2] Jeong OC, Konishi S. Three-dimensionally combinined carbonized polymer sensor and heater. Sens Actuators A 2008;143:97–105.
[3] Wang C, Taherabadi L, Jia G, Madou M, Yeh Y, Dunn B. CMEMS for the manufacture of 3D microbatteries. Electrochem Solid-State Lett 2004;7(11):A435–8. [4] Lau KH, Li KY. Correlation between adhesion and wear behaviour of commercial carbon based coating. Tribol Int 2006;39:115–23. [5] Park BY, Taherabadi L, Wang C, Zoval J, Madou MJ. Electrical properties and shrinkage of carbonized photoresist films and implications for carbon microelectromechanical systems devices in conductive media. J Electrochem Soc 2005;152(12):J136–43. [6] Hsu YC, Chung DDL. Silver particle carbon–matrix composites as thick films for electrical applications. J Electron Mater 2007;36(9):1188–92. [7] Sebastien J, Arnaud B, Heinrich H, Philippe R. SU8-silver photosensitive nanocomposite. Adv Eng Mater 2004;6(9):719–24. [8] A.Singh, J.Jayaram, M.Madou, S.Akbar. Pyrolysis of negative photoresists to fabricate carbon structures for microelectromechanical systems and electrochemical applications. J Electrochem Soc 2002;149(3):E78–83. [9] Chalker PR, Bull SJ, Rickerby DS. A review of the methods for the evaluation of coating-substrate adhesion. Mater Sci Eng 1991;A140:583–92. [10] Weast RC, Astle MJ. CRC handbook of chemistry and physics. Florida, USA: CRC Press, Inc.; 1978. p. F-170.
Easy deposition of amorphous carbon films on glass substrates A.B. Bourlinosa,*, V. Georgakilasa, R. Zborilb a
Institute of Materials Science, NCSR ‘‘Demokritos’’, Ag. Paraskevi Attikis, Athens 15310, Greece Department of Physical Chemistry, Palacky University, Olomouc 77146, Czech Republic
b
A R T I C L E I N F O
A B S T R A C T
Article history:
The easy fabrication of amorphous carbon films on glass substrates is described. The films
Received 10 December 2007
are obtained by a simple gas phase deposition technique that takes place in air under mild
Accepted 11 July 2008 Available online 22 July 2008
conditions (400 C, ambient pressure). The experimental set-up is straightforward and can be routinely applied for the large-scale fabrication of high quality carbon films, while, the carbon source is a decomposable polymer precursor (polyvinylpyrrolidone, PVP). 2008 Elsevier Ltd. All rights reserved.
Carbon thin films contain predominately carbon and moderate amounts of property-influential heteroatoms such as H, N or O. They are usually amorphous with a mixture of sp2 and sp3 carbon atoms and are deposited in the form of granular thin films with thicknesses of a few micrometers. For a number of years, the technologically attractive properties of carbon films have drawn an almost unparalleled interest [1–6], which include high hardness, low friction, electrical insula-
tion, optical transparency, smoothness, protection and resistance to wear. Carbon thin films on glass substrates are mainly produced using chemical vapour, plasma, pulsed laser, electron gun, ion beam or sputtering deposition techniques [1–6]. These methods are largely preferred over simply coating a substrate with an organic precursor and subsequent carbonization [7] because gas phase deposition techniques ultimately lead to
* Corresponding author: Fax: +30 210 6519430. E-mail addresses: [email protected] (A.B. Bourlinos). 0008-6223/$ - see front matter 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbon.2008.07.013
1802
CARBON
4 6 ( 2 0 0 8 ) 1 7 9 2 –1 8 2 8
Fig. 1 – Carbon film on glass substrate.
films of superior quality. Nevertheless, they often require a sophisticated apparatus as well as strict deposition conditions, like vacuum or an inert atmosphere, flammable hydrocarbon mixtures as the carbon source, gas flow adjustments and relatively high carbonization temperatures [1–6]. Here we report a cost-effective alternative technique to fabricate granular amorphous carbon films containing H, N and O in a more direct and convenient way. The deposition is carried out in the gas phase in air under mild temperature and ambient pressure, the experimental set-up is straightforward and can be routinely applied for the large-scale fabrication of carbon films, and, the carbon source is polyvi-
Fig. 2 – Left: FT-IR spectra of PVP (a) and carbon film (b). Right: Raman spectrum of the carbon film. nylpyrrolidone (PVP) that is decomposable, but is safe and easy to handle. Overall, the present method leads to high quality carbon films with structural and textural features quite reminiscent of those obtained using the aforementioned techniques [1–6]. The optical and wetting properties of the films are also briefly discussed. For this purpose a porcelain crucible (height: 3.5 cm, base diameter: 3 cm, top open diameter: 4.5 cm) and a pre-cleaned microscope glass slide (thickness: 1 mm, 2.5 cm · 7.5 cm) is used. In detail, 2 g PVP (K 15, Mr 10000, Fluka) were uni-
Fig. 3 – SEM micrographs of the carbon film on glass substrate.
CARBON
4 6 ( 20 0 8 ) 1 7 9 2–18 2 8
formly spread on the bottom of the porcelain crucible. Then the glass slide was placed horizontally on top of the porcelain crucible with the deposition surface facing towards the PVP precursor at a distance of 3 cm. The crucible-glass slide system was placed at the center of a box furnace (Carbolite, model CWF 11/5) and heated in air at 400 C for 2 h and at a heating rate of 10 C min1. In this instance, PVP decomposes at 200 C releasing volatile organic compounds [8,9]. The released carbon-containing molecules are then thermally decomposed at higher temperatures in the gas phase to form amorphous carbon particles that eventually deposit as a thin film on the exposed surface of the glass slide. At the end of this process, PVP has been fully converted to a black waste residue at the bottom of the crucible. The as-formed darkbrown film has a great coherence with the glass substrate, it is smooth and homogeneous, and it is optically transparent (Fig. 1). Elemental analysis (%): C, 44.25; H, 2.49; N, 26.32; O, 26.94, agrees with the average formula C2.2H1.5ON1.1. The carbon film is virtually insoluble in any solvent, including acid or alkaline aqueous solutions, and degrades above 400 C (based on TGA in air). Besides simplicity and cheapness, the method has additional advantages: (i) the amount of PVP determines the thickness of the film, i.e. the less the loaded amount the thinner the film under identical experimental conditions; (ii) it is possible to control the composition of the film using co-deposition from a mixture of decomposable precursors; (iii) the particular gas phase deposition technique may allow the template printing of precise patterns and morphologies based on carbon [10,11]. The polymer precursor (PVP) exhibits a rich IR spectrum with the most prominent feature being the amide band of the pyrrolidone ring at 1620 cm1 [8,9] (Fig. 2). In contrast, the as-deposited carbon film shows very weak, broad absorptions near 1600 cm1 (C@C, C@N, C@O) [6] (Fig. 2). On the other hand, the corresponding Raman spectrum shows characteristic peaks at 1347 cm1 and 1571 cm1, attributed to sp3 and sp2 carbon bonds, respectively (Fig. 2). The relative intensities of these bands together with the broadness of the sig-
Fig. 4 – TEM image of the carbogenic product. The inset includes the corresponding SAD pattern.
1803
nals indicate the formation of amorphous carbon particles [12]. SEM analysis revealed the formation of a dense, continuous film with approximately circular depressions in the surface that resemble craters (Fig. 3A). A closer look at the surface (Fig. 3B) showed globular specimens lying on top of the as-deposited film and sharing a common stoichiometry with the bulk, based on EDX analysis. This finding indicates the granular texture of the film, and pinpoints the gradual deposition and accumulation of carbon particles from the gas phase. Further observation near the film’s edges (Fig. 3C and D) showed the presence of densely packed or even fused grains with sizes in the range 0.2–0.5 lm and also a film thickness of 5 lm. It is worth noting that, TEM examination (Fig. 4) reveals that the large grains observed in the SEM are actually agglomerates of several smaller particles. To that end, the film was peeled off by immersing the coated slide in water, and the obtained solid was subjected to intense ultrasonication. Indeed, this treatment would break down the granular agglomerates into smaller particles with sizes ranging between 10 and 30 nm. Moreover, these particles have an isotropic amorphous structure as evidenced by the corresponding SAD pattern (Fig. 4, inset). As mentioned earlier the thickness of a deposited film can be adjusted by the amount of PVP loaded in the porcelain crucible. This effect is clearly reflected in the optical properties of the films where thicker films tend to block a wider range of wavelengths while still retaining transparency (Fig. 5). Such behavior could be valuable in UV–Vis filters with moderate blocking capacity. Another interest is the wetting properties of the films [13]. The film is inherently hydrophilic due to the presence of oxygen and nitrogen heteroatoms. When a water droplet is placed on the surface this spreads evenly thus wetting the film (contact angle: 5). However, fixation of C8F17CH2CH2Si(OEt)3 (Aldrich) on the surface through –OH and –COOH reactive centers forms a dense coating on top of the carbon film that renders it hydrophobic (contact angle: 120) [13] (Fig. 5). In summary, carbon films on glass substrates were obtained by a simple gas phase deposition technique that takes
Fig. 5 – Left: UV–Vis spectra of (a) uncoated glass, (b,c) carbon films of different thickness (PVP loadings–SEM thickness: (b) 0.5 g–2 lm; (c) 2 g–5 lm). Right: a water droplet on neat carbon film (top) and over the hydrophobic surface (bottom).
1804
CARBON
4 6 ( 2 0 0 8 ) 1 7 9 2 –1 8 2 8
place in air under mild conditions without the need of any special apparatus or condition. The method leads to optically transparent, smooth films that strongly adhere to the glass substrate. The film is structurally amorphous containing sp2 and sp3 carbon atoms and also H, N and O heteroatoms. The film is several micrometers thick, and exhibits a granular texture with densely packed grains with a size of 0.2–0.5 lm. Each grain seems to be a cluster of smaller carbon particles of size 10–30 nm. The films hold promise for use in optical filters and moderately engineered surfaces.
[4]
[5]
[6]
Acknowledgement
[7]
This work was supported by the projects of the ministry of education of the Czech Republic (1M6198952901 and MSM6198959218).
[8]
[9] R E F E R E N C E S
[10] [1] Zaharia T, Sullivan JL, Saied SO, Bosch RCM, Bijker MD. Fast deposition of diamond-like hydrogenated carbon films. Diamond Relat Mater 2007;16:623–9. [2] Lin H-C, Shiue S-T, Cheng Y-H, Yang T-J, Wu T-C, Lin H-Y. Characteristics of carbon coatings on optical fibers prepared by plasma enhanced chemical vapor deposition using different argon/methane ratios. Carbon 2007;45:2004–10. [3] Eryilmaz OL, Johnson JA, Ajayi OO, Erdemir A. Deposition, characterization, and tribological applications of near-
[11]
[12]
[13]
frictionless carbon films on glass and ceramic substrates. J Phys: Condens Matter 2006;18:S1751–62. Cappelli E, Orlando S, Mattei G, Scilletta C, Corticelli F, Ascarelli P. Nano-structured oriented carbon films grown by PLD and CVD methods. Appl Phys A 2004;79:2063–8. Taylor CA, Chiu WKS. Characterization of CVD carbon films for hermetic optical fiber coatings. Surf Coat Technol 2003;168:1–11. Thie`ry F, Valle´e C, Pauleau Y, Gaboriau F, Lacoste A, Arnal Y, et al. Characterization of amorphous hydrogenated carbon films deposited from CO–C2H2 mixtures in a distributed ECR plasma reactor. Surf Coat Technol 2002; 151–2:165–9. Ray SC, Fanchini G, Tagliaferro A, Bose B, Dasgupta D. Amorphous carbon films prepared by the ‘‘dip’’ technique: deposition and film characterization. J Appl Phys 2003;94:870–8. Du YK, Yang P, Mou ZG, Hua NP, Jiang L. Thermal decomposition behaviors of PVP coated on platinum nanoparticles. J Appl Polym Sci 2006;99:23–6. Bogatyrev VM, Borisenko NV, Pokrovskii VA. Thermal degradation of polyvinylpyrrolidone on the surface of pyrogenic silica. Russ J Appl Chem 2001;74:839–44. Schneider JJ, Engstler J. Carbon and polymer filaments in nanoporous alumina. Eur J Inorg Chem 2006:1723–36. Guise O, Ahner J, Yates J, Levy J. Formation and thermal stability of sub-10-nm carbon templates on Si(100). Appl Phys Lett 2004;85:2352–4. Schwan J, Ulrich S, Batori V, Ehrhardt H, Silva SRP. Raman spectroscopy on amorphous carbon films. J Appl Phys 1996;80:440–7. Li H, Wang X, Song Y, Liu Y, Li Q, Jiang L, et al. Superamphiphobic aligned carbon nanotube films. Angew Chem Int Ed 2001;40:1743–6.
Carbon formation promoted by hydrogen peroxide in supercritical water Ki Chul Parka,b,*, Hiroshi Tomiyasua, Shingo Morimotoc, Kenji Takeuchib, Yong Jung Kimd, Morinobu Endob,d,* a
Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology (TIT), 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan Department of Electrical and Electronic Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan c Nagano Techno Foundation (NTF), 1-18-1 Wakasato, Nagano 380-0928, Japan d Institute of Carbon Science and Technology (ICST), Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan b
A R T I C L E I N F O
A B S T R A C T
Article history:
A limited use of hydrogen peroxide in supercritical water has produced graphitic carbons
Received 13 March 2008
from hydrocarbons at the low temperature of 400 C. The choice of precursor hydrocarbons
Accepted 30 April 2008 Available online 8 August 2008
leads to morphological and microstructural variations. The use of n-hexane has provided chain-like interlinked nanoparticles comprised of graphitic layers, while benzene has been converted to a fine spherical shape of colloidal carbons with sub-micron size. The microstructure of the colloidal carbons is comprised of smaller aromatic clusters than
* Corresponding authors: Address: Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology (TIT), 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan (K.C. Park). Fax: +81 26 269 5667 (K.C. Park). E-mail addresses: [email protected] (K.C. Park), [email protected] (M. Endo). 0008-6223/$ - see front matter 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbon.2008.04.028
1801
4 6 ( 20 0 8 ) 1 7 9 2–18 2 8
ume fraction and electrical resistivity is much lower than those in prior related work at the same carbonization temperature. Although any of the fillers diminished the scratch resistance of the carbon film, carbon film including nickel showed higher scratch resistance than carbon film including the MWCNT at a similar filler volume fraction.
Acknowledgement Partial support of this work by the Mark Diamond Research Fund, University at Buffalo, State University of New York, is hereby acknowledged.
R E F E R E N C E S
[1] Yamada Y, Chung DDL. Three-dimensional microstructuring of carbon by thermoplastic spacer evaporation during pyrolysis. Carbon, in press, doi:10.1016/j.carbon.2008.07.031. [2] Jeong OC, Konishi S. Three-dimensionally combinined carbonized polymer sensor and heater. Sens Actuators A 2008;143:97–105.
[3] Wang C, Taherabadi L, Jia G, Madou M, Yeh Y, Dunn B. CMEMS for the manufacture of 3D microbatteries. Electrochem Solid-State Lett 2004;7(11):A435–8. [4] Lau KH, Li KY. Correlation between adhesion and wear behaviour of commercial carbon based coating. Tribol Int 2006;39:115–23. [5] Park BY, Taherabadi L, Wang C, Zoval J, Madou MJ. Electrical properties and shrinkage of carbonized photoresist films and implications for carbon microelectromechanical systems devices in conductive media. J Electrochem Soc 2005;152(12):J136–43. [6] Hsu YC, Chung DDL. Silver particle carbon–matrix composites as thick films for electrical applications. J Electron Mater 2007;36(9):1188–92. [7] Sebastien J, Arnaud B, Heinrich H, Philippe R. SU8-silver photosensitive nanocomposite. Adv Eng Mater 2004;6(9):719–24. [8] A.Singh, J.Jayaram, M.Madou, S.Akbar. Pyrolysis of negative photoresists to fabricate carbon structures for microelectromechanical systems and electrochemical applications. J Electrochem Soc 2002;149(3):E78–83. [9] Chalker PR, Bull SJ, Rickerby DS. A review of the methods for the evaluation of coating-substrate adhesion. Mater Sci Eng 1991;A140:583–92. [10] Weast RC, Astle MJ. CRC handbook of chemistry and physics. Florida, USA: CRC Press, Inc.; 1978. p. F-170.
Easy deposition of amorphous carbon films on glass substrates A.B. Bourlinosa,*, V. Georgakilasa, R. Zborilb a
Institute of Materials Science, NCSR ‘‘Demokritos’’, Ag. Paraskevi Attikis, Athens 15310, Greece Department of Physical Chemistry, Palacky University, Olomouc 77146, Czech Republic
b
A R T I C L E I N F O
A B S T R A C T
Article history:
The easy fabrication of amorphous carbon films on glass substrates is described. The films
Received 10 December 2007
are obtained by a simple gas phase deposition technique that takes place in air under mild
Accepted 11 July 2008 Available online 22 July 2008
conditions (400 C, ambient pressure). The experimental set-up is straightforward and can be routinely applied for the large-scale fabrication of high quality carbon films, while, the carbon source is a decomposable polymer precursor (polyvinylpyrrolidone, PVP). 2008 Elsevier Ltd. All rights reserved.
Carbon thin films contain predominately carbon and moderate amounts of property-influential heteroatoms such as H, N or O. They are usually amorphous with a mixture of sp2 and sp3 carbon atoms and are deposited in the form of granular thin films with thicknesses of a few micrometers. For a number of years, the technologically attractive properties of carbon films have drawn an almost unparalleled interest [1–6], which include high hardness, low friction, electrical insula-
tion, optical transparency, smoothness, protection and resistance to wear. Carbon thin films on glass substrates are mainly produced using chemical vapour, plasma, pulsed laser, electron gun, ion beam or sputtering deposition techniques [1–6]. These methods are largely preferred over simply coating a substrate with an organic precursor and subsequent carbonization [7] because gas phase deposition techniques ultimately lead to
* Corresponding author: Fax: +30 210 6519430. E-mail addresses: [email protected] (A.B. Bourlinos). 0008-6223/$ - see front matter 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbon.2008.07.013
1802
CARBON
4 6 ( 2 0 0 8 ) 1 7 9 2 –1 8 2 8
Fig. 1 – Carbon film on glass substrate.
films of superior quality. Nevertheless, they often require a sophisticated apparatus as well as strict deposition conditions, like vacuum or an inert atmosphere, flammable hydrocarbon mixtures as the carbon source, gas flow adjustments and relatively high carbonization temperatures [1–6]. Here we report a cost-effective alternative technique to fabricate granular amorphous carbon films containing H, N and O in a more direct and convenient way. The deposition is carried out in the gas phase in air under mild temperature and ambient pressure, the experimental set-up is straightforward and can be routinely applied for the large-scale fabrication of carbon films, and, the carbon source is polyvi-
Fig. 2 – Left: FT-IR spectra of PVP (a) and carbon film (b). Right: Raman spectrum of the carbon film. nylpyrrolidone (PVP) that is decomposable, but is safe and easy to handle. Overall, the present method leads to high quality carbon films with structural and textural features quite reminiscent of those obtained using the aforementioned techniques [1–6]. The optical and wetting properties of the films are also briefly discussed. For this purpose a porcelain crucible (height: 3.5 cm, base diameter: 3 cm, top open diameter: 4.5 cm) and a pre-cleaned microscope glass slide (thickness: 1 mm, 2.5 cm · 7.5 cm) is used. In detail, 2 g PVP (K 15, Mr 10000, Fluka) were uni-
Fig. 3 – SEM micrographs of the carbon film on glass substrate.
CARBON
4 6 ( 20 0 8 ) 1 7 9 2–18 2 8
formly spread on the bottom of the porcelain crucible. Then the glass slide was placed horizontally on top of the porcelain crucible with the deposition surface facing towards the PVP precursor at a distance of 3 cm. The crucible-glass slide system was placed at the center of a box furnace (Carbolite, model CWF 11/5) and heated in air at 400 C for 2 h and at a heating rate of 10 C min1. In this instance, PVP decomposes at 200 C releasing volatile organic compounds [8,9]. The released carbon-containing molecules are then thermally decomposed at higher temperatures in the gas phase to form amorphous carbon particles that eventually deposit as a thin film on the exposed surface of the glass slide. At the end of this process, PVP has been fully converted to a black waste residue at the bottom of the crucible. The as-formed darkbrown film has a great coherence with the glass substrate, it is smooth and homogeneous, and it is optically transparent (Fig. 1). Elemental analysis (%): C, 44.25; H, 2.49; N, 26.32; O, 26.94, agrees with the average formula C2.2H1.5ON1.1. The carbon film is virtually insoluble in any solvent, including acid or alkaline aqueous solutions, and degrades above 400 C (based on TGA in air). Besides simplicity and cheapness, the method has additional advantages: (i) the amount of PVP determines the thickness of the film, i.e. the less the loaded amount the thinner the film under identical experimental conditions; (ii) it is possible to control the composition of the film using co-deposition from a mixture of decomposable precursors; (iii) the particular gas phase deposition technique may allow the template printing of precise patterns and morphologies based on carbon [10,11]. The polymer precursor (PVP) exhibits a rich IR spectrum with the most prominent feature being the amide band of the pyrrolidone ring at 1620 cm1 [8,9] (Fig. 2). In contrast, the as-deposited carbon film shows very weak, broad absorptions near 1600 cm1 (C@C, C@N, C@O) [6] (Fig. 2). On the other hand, the corresponding Raman spectrum shows characteristic peaks at 1347 cm1 and 1571 cm1, attributed to sp3 and sp2 carbon bonds, respectively (Fig. 2). The relative intensities of these bands together with the broadness of the sig-
Fig. 4 – TEM image of the carbogenic product. The inset includes the corresponding SAD pattern.
1803
nals indicate the formation of amorphous carbon particles [12]. SEM analysis revealed the formation of a dense, continuous film with approximately circular depressions in the surface that resemble craters (Fig. 3A). A closer look at the surface (Fig. 3B) showed globular specimens lying on top of the as-deposited film and sharing a common stoichiometry with the bulk, based on EDX analysis. This finding indicates the granular texture of the film, and pinpoints the gradual deposition and accumulation of carbon particles from the gas phase. Further observation near the film’s edges (Fig. 3C and D) showed the presence of densely packed or even fused grains with sizes in the range 0.2–0.5 lm and also a film thickness of 5 lm. It is worth noting that, TEM examination (Fig. 4) reveals that the large grains observed in the SEM are actually agglomerates of several smaller particles. To that end, the film was peeled off by immersing the coated slide in water, and the obtained solid was subjected to intense ultrasonication. Indeed, this treatment would break down the granular agglomerates into smaller particles with sizes ranging between 10 and 30 nm. Moreover, these particles have an isotropic amorphous structure as evidenced by the corresponding SAD pattern (Fig. 4, inset). As mentioned earlier the thickness of a deposited film can be adjusted by the amount of PVP loaded in the porcelain crucible. This effect is clearly reflected in the optical properties of the films where thicker films tend to block a wider range of wavelengths while still retaining transparency (Fig. 5). Such behavior could be valuable in UV–Vis filters with moderate blocking capacity. Another interest is the wetting properties of the films [13]. The film is inherently hydrophilic due to the presence of oxygen and nitrogen heteroatoms. When a water droplet is placed on the surface this spreads evenly thus wetting the film (contact angle: 5). However, fixation of C8F17CH2CH2Si(OEt)3 (Aldrich) on the surface through –OH and –COOH reactive centers forms a dense coating on top of the carbon film that renders it hydrophobic (contact angle: 120) [13] (Fig. 5). In summary, carbon films on glass substrates were obtained by a simple gas phase deposition technique that takes
Fig. 5 – Left: UV–Vis spectra of (a) uncoated glass, (b,c) carbon films of different thickness (PVP loadings–SEM thickness: (b) 0.5 g–2 lm; (c) 2 g–5 lm). Right: a water droplet on neat carbon film (top) and over the hydrophobic surface (bottom).
1804
CARBON
4 6 ( 2 0 0 8 ) 1 7 9 2 –1 8 2 8
place in air under mild conditions without the need of any special apparatus or condition. The method leads to optically transparent, smooth films that strongly adhere to the glass substrate. The film is structurally amorphous containing sp2 and sp3 carbon atoms and also H, N and O heteroatoms. The film is several micrometers thick, and exhibits a granular texture with densely packed grains with a size of 0.2–0.5 lm. Each grain seems to be a cluster of smaller carbon particles of size 10–30 nm. The films hold promise for use in optical filters and moderately engineered surfaces.
[4]
[5]
[6]
Acknowledgement
[7]
This work was supported by the projects of the ministry of education of the Czech Republic (1M6198952901 and MSM6198959218).
[8]
[9] R E F E R E N C E S
[10] [1] Zaharia T, Sullivan JL, Saied SO, Bosch RCM, Bijker MD. Fast deposition of diamond-like hydrogenated carbon films. Diamond Relat Mater 2007;16:623–9. [2] Lin H-C, Shiue S-T, Cheng Y-H, Yang T-J, Wu T-C, Lin H-Y. Characteristics of carbon coatings on optical fibers prepared by plasma enhanced chemical vapor deposition using different argon/methane ratios. Carbon 2007;45:2004–10. [3] Eryilmaz OL, Johnson JA, Ajayi OO, Erdemir A. Deposition, characterization, and tribological applications of near-
[11]
[12]
[13]
frictionless carbon films on glass and ceramic substrates. J Phys: Condens Matter 2006;18:S1751–62. Cappelli E, Orlando S, Mattei G, Scilletta C, Corticelli F, Ascarelli P. Nano-structured oriented carbon films grown by PLD and CVD methods. Appl Phys A 2004;79:2063–8. Taylor CA, Chiu WKS. Characterization of CVD carbon films for hermetic optical fiber coatings. Surf Coat Technol 2003;168:1–11. Thie`ry F, Valle´e C, Pauleau Y, Gaboriau F, Lacoste A, Arnal Y, et al. Characterization of amorphous hydrogenated carbon films deposited from CO–C2H2 mixtures in a distributed ECR plasma reactor. Surf Coat Technol 2002; 151–2:165–9. Ray SC, Fanchini G, Tagliaferro A, Bose B, Dasgupta D. Amorphous carbon films prepared by the ‘‘dip’’ technique: deposition and film characterization. J Appl Phys 2003;94:870–8. Du YK, Yang P, Mou ZG, Hua NP, Jiang L. Thermal decomposition behaviors of PVP coated on platinum nanoparticles. J Appl Polym Sci 2006;99:23–6. Bogatyrev VM, Borisenko NV, Pokrovskii VA. Thermal degradation of polyvinylpyrrolidone on the surface of pyrogenic silica. Russ J Appl Chem 2001;74:839–44. Schneider JJ, Engstler J. Carbon and polymer filaments in nanoporous alumina. Eur J Inorg Chem 2006:1723–36. Guise O, Ahner J, Yates J, Levy J. Formation and thermal stability of sub-10-nm carbon templates on Si(100). Appl Phys Lett 2004;85:2352–4. Schwan J, Ulrich S, Batori V, Ehrhardt H, Silva SRP. Raman spectroscopy on amorphous carbon films. J Appl Phys 1996;80:440–7. Li H, Wang X, Song Y, Liu Y, Li Q, Jiang L, et al. Superamphiphobic aligned carbon nanotube films. Angew Chem Int Ed 2001;40:1743–6.
Carbon formation promoted by hydrogen peroxide in supercritical water Ki Chul Parka,b,*, Hiroshi Tomiyasua, Shingo Morimotoc, Kenji Takeuchib, Yong Jung Kimd, Morinobu Endob,d,* a
Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology (TIT), 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan Department of Electrical and Electronic Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan c Nagano Techno Foundation (NTF), 1-18-1 Wakasato, Nagano 380-0928, Japan d Institute of Carbon Science and Technology (ICST), Shinshu University, 4-17-1 Wakasato, Nagano 380-8553, Japan b
A R T I C L E I N F O
A B S T R A C T
Article history:
A limited use of hydrogen peroxide in supercritical water has produced graphitic carbons
Received 13 March 2008
from hydrocarbons at the low temperature of 400 C. The choice of precursor hydrocarbons
Accepted 30 April 2008 Available online 8 August 2008
leads to morphological and microstructural variations. The use of n-hexane has provided chain-like interlinked nanoparticles comprised of graphitic layers, while benzene has been converted to a fine spherical shape of colloidal carbons with sub-micron size. The microstructure of the colloidal carbons is comprised of smaller aromatic clusters than
* Corresponding authors: Address: Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology (TIT), 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan (K.C. Park). Fax: +81 26 269 5667 (K.C. Park). E-mail addresses: [email protected] (K.C. Park), [email protected] (M. Endo). 0008-6223/$ - see front matter 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.carbon.2008.04.028