University of Central Florida STARS UCF Patents Technology Transfer 4-23-1996 CVD Method of Producing and Doping Fullerenes Lee Chow University of Central Florida Find similar works at: https://stars.library.ucf.edu/patents University of Central Florida Libraries http://library.ucf.edu This Patent is brought to you for free and open access by the Technology Transfer at STARS. It has been accepted for inclusion in UCF Patents by an authorized administrator of STARS. For more information, please contact [email protected]. Recommended Citation Chow, Lee, "CVD Method of Producing and Doping Fullerenes" (1996). UCF Patents. 104. https://stars.library.ucf.edu/patents/104 Illlll llllllll Ill lllll lllll lllll lllll lllll 111111111111111111111111111111111 US005510098A United States Patent [19J [llJ Patent Number: 5,510,098 Chow [45J Date of Patent: Apr. 23, 1996 [54) CVD METHOD OF PRODUCING AND Chemical Abstracts, vol. 118, #237042d (1993). DOPING FULLERENES Patent Abstracts of Japan, vol. 17, #259, (C-1061), May 21, 1993, abstract for Surnino, JP-05--4810 (14 Jan. 1993). [75] Inventor: Lee Chow, Orlando, Fla. Powell, C. F., et al. "Vapor-plating: The Formation of [73) Assignee: University of Central Florida, Coatings by Vapor Deposition Techniques", John Wiley: Orlando, Fla. New York, 1955, pp. 1-13 and 71. Howard et al., Fullerenes C60 and C70 in flames, Nature, [21] Appl. No.: 176,543 vol. 352 Jul. 11, 1991. [22] Filed: Jan. 3, 1994 Kratschmer et al., Solid C60: a new form of carbon, Nature, vol. 347, Sep. 27, 1990, pp. 354-358. 6 [51J Int. cI. ••••••••••••••••.•..•...•.••••.••.••••••••••••.•.•••• corn 31100 Kroto et al., C60: Buckminsterfullerene, Nature, vol. 318, [52) U.S. CI . ..................... 423/445 B; 423/446; 423/262; Nov. 15, 1985, pp. 162-163. 423/263; 423/439 [58] Field of Search ................................ 423/446, 445 B, McKinnon et al., Combustion Synthesis ofFullerenes, Com­ 423/262, 263, 439 bustion And Flame 88: 1992, pp. 102-112. [56] References Cited Primary Examiner-Michael Lewis Assistant Examiner-Peter T. DiMauro U.S. PATENT DOCUMENTS Attorney, Agent, or Firm-Brian S. Steinberger 4,221,608 9/1980 Beckman ................................ 106/307 4,849,199 7/1989 Pinneo .................................... 423/446 [57) ABSTRACT 5,108,779 4/1992 Gasworth ................................ 423/446 5,132,105 7/1992 Remo ...................................... 423/446 Methods of producing fullerenes in large-macroscopic quan­ 5,196,396 3/1993 Lieber ......................................... 505/1 tities inexpensively is disclosed without using solid carbon 5,209,812 5/1993 Wu et al. ................................ 423/446 material such as graphite. In a preferred embodiment, 5,223,479 6/1993 McCauley, Jr. et al. ................... 50511 fullerenes are formed by a hot filament CVD procedure. The 5,227,038 7/1993 Smalley et al .......................... 204/173 5,239,820 8/1993 Leifer et al. .............................. 601202 fullerenes occur in the soot that forms as a by-product on the 5,273,731 12/1993 Anthony et al ......................... 423/446 edges of the substrate holder. Mass spectrum of soot deposits shows lines corresponding to C60. From the typical concen­ FOREIGN PATENT DOCUMENTS trations of gaseous species in the diamond-growing CVD 2091665 10/1993 Canada .............................. 423/445 B chamber, hydrocarbon species including CH3 or C2 H2 can W092/20622 1111992 WIPO ............................ COlB 31/00 be the precursors for the formation of fullerenes in the CVD chamber. A method of using fullerenes to enhance the OTHER PUBLICATIONS properties of rubber composites is also described. Dai, G., et al. "A New Technique for Synthesizing Fullerene C60", in 'Gaoden Xuexiao Huaxve Xueba', vol. 13, #7 (1992), pp. 893-894. 15 Claims, 3 Drawing Sheets 103.A Gas In 130 Gas In 108 107 140 106 U.S. Patent Apr. 23, 1996 Sheet 1of3 5,510,098 0 T"""""" <( a::i Ct) Ct) 0 0 T""" T""" I.() 0 T""" . C) LL 0v T""" 0 "T""" (0 0 T""" 0 Ct) T""" co 0 T""" 81 T""" U.S. Patent Apr. 23, 1996 Sheet 2 of 3 5,510,098 U.S. Patent Apr. 23, 1996 Sheet 3 of 3 5,510,098 200 Confine the filament and substrate in reaction chamber - 205 Pump down to 10·3 torr ~ 210 '--~~~~~~~~~~~--' ,J., Introduce methane and hydrogen - 215 ......_~_c_a_r_bo_n_iz_e_d_t_h_e_fi_la_m_e_n_t~____.r---- 220 -J.. Turn off the power to the filament _ and pump down to 10-3 torr 225 Fig. 3 Introduce methane and hydrogen - 230 Bring the substrate near - 240 the filament Turn on the power to the filament - 250 Diamond deposited on substrate where T:::::900°C. 260 Carbon soot deposited on substrate - holder where T < 800°C. Remove substrate and substrate _ 270 holder from chamber Remove soot from substrate holder r---- 280 ,J., Extract fullerness from soot - 285 5,510,098 1 2 CVD METHOD OF PRODUCING AND favor diamond deposition. Mass spectrum of graphed soot DOPING FULLERENES deposits retrieved from the chamber shows lines correspond­ ing to fullerenes, c60' This invention relates to fullerenes, and in particular to A method of using fullerenes as a rubber reinforcement producing and doping fullerenes by a hot filament CVD 5 agent to enhance rubber properties such as tensile strength, method and a method for utilizing fullerenes as a rubber wear and tear resistance is also disclosed. reinforcement agent. Further objects and advantages of this invention will be apparent from the following detailed description of a pres­ BACKGROUND AND PRIOR ART ently preferred embodiment which is illustrated schemati­ Fullerenes consist of 60 carbon atoms bonded together lO cally in the accompanying drawings. and were the first molecule synthesized that had a perfect spherical shape. Fullerenes were first discovered in 1985. BRIEF DESCRIPTION OF THE FIGURES Uses for fullerenes are expanding into many areas. For FIG. 1 illustrates an apparatus and method of producing example, alkali metal-doped C60 are high temperature super­ 15 conductors with temperature ranging from 10° K. to 35° K. fullerenes by Hot Filament CVD. c60 has shown to have strong optical limiting properties. FIG. 2 shows a mass spectrum of the soot collected in the Under high pressure, C60 transforms into diamonds. Ion CVD chamber. bombarded fullerenes can increase the nucleation of CVD FIG. 3 illustrates a flow chart for the hot filament CVD diamond by 10 orders of magnitude. 20 method for fullerenes synthesis. A problem with some known processes are that some are limited to producing only several grams of C6ofC70 mixture DESCRIPTION OF THE PREFERRED per day and require value-added products such as graphite. EMBODIMENT Under the carbon arc method, carbon is vaporized with the heat from an electrical arc, fullerene molecules along with 25 Before explaining the disclosed embodiment of the graphite carbon molecules are then condensed and collected present invention in detail it is to be understood that the as solid soot material. The fullerenes can then be purified by invention is not limited in its application to the details of the extracting the soot with an appropriate solvent followed by particular arrangement shown since the invention is capable evaporation of the solvent to yield the solid fullerene mate­ of other embodiments. Also, the terminology used herein is rial. U.S. Pat. No. 5,227,038 to Smalley et al. describes such 30 for the purpose of description and not of limitation. a method. Fullerenes have also been made by a process involving vaporizing carbon from a rotating disk of graphite Method for Producing and Doping Fullerenes into a helium flow using a focussed laser since 1985, as described by Kroto et at. in an article entitled "C60: Buck­ FIG. 1 illustrates an apparatus 100 for producing minsteffullerene", Nature, vol. 318, Nov. 14, 1985, pages 35 fullerenes by Hot Filament Chemical Vapor Deposition­ 162-163. (CVD) method. In FIG. 1, experiments were performed in a conventional hot filament CVD chamber 130 using an SUMMARY OF THE INVENTION approximately straight 0.75-mm diameter tungsten filament 125 approximately 7 cm long. The current from power The first objective of the present invention is to provide a 40 supply 104 was maintained at approximately 55 A, and the method of producing fullerenes using a Chemical Vapor filament temperature was estimated to be approximately Deposidon(CVD) method. 2200 degrees C. Gases from inlets 103A and 103B were feed The second object of this invention is to provide a method into chamber 130. The gases were approximately 99.8% of producing fullerenes without using value-added products pure CH4 mixed with approximately 99.999% pure H2 . The such as graphite. 45 pressure inside the chamber was maintained between The third object of this invention is to provide a method approximately 30-60 torr using a vacuum pump 106 and a of producing fullerenes inexpensively in large-macroscopic variable valve 107. The flow rate was controlled at approxi­ quantities. mately 0.4 seem for CH4 and approximately 99.6 seem for In a preferred embodiment, fullerenes are formed during H2 . A stainless steel substrate holder 110 was used, and a diamond synthesis by a hot filament CVD procedure. In this 50 scratched Si wafer 112 was used as the substrate. The substrate temperature, monitored by both thermocouple 140 CVD procedure, H2 and carbon-containing gas (i.e. CH4 or and pyrometer 145 was kept between approximately 900° to C2 H2) are admitted into a growth chamber. The pressure inside the growth chamber is controlled by the pumping rate approximately 950° C. This temperature is maintained by through a valve, and the flow rate of the carbon-containing adjusting the distance between substrate 112 and filament gases. The preferred range of pressure is approximately 55 125 using a translational stage 108. A typical run lasted 30-100 torr. A pressure of approximately 10-1000 torr.