JP2004189595A - Fullerene polymer and fullerene polymer membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fullerene polymer high in electrical conductivity (electrical conductance), excellent in transparency and high in mechanical strength, while excellent properties that fullerene has originally are held, and to provide a fullerene polymer membrane composed of the same fullerene polymer. <P>SOLUTION: The fullerene polymer composed of a structure d and the like is obtained by polymerizing plural molecules of fullerene expressed by C<SB>n</SB>(wherein, n is 60 or 70 where a spherical compound is geometrically formed). The fullerene polymer membrane is composed of this fullerene polymer. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a fullerene polymer and a fullerene polymer film.

  The existence of fullerene, a globular carbon compound, was clarified as the third crystalline carbon next to diamond and graphite, and it was only in 1990 that a macromolecular synthesis method was established.

Fullerene is a series of spherical carbon compounds composed of only carbon, and is a generic name of so-called Higher Fullerenes composed of C60 composed of ₆₀ carbons and an even number of carbons, and includes 12 5-membered rings and 20 or It contains more 6-membered rings. That is, 60, 70, 74, 76, 78, 80, 82, or 84 carbon atoms (the number of carbon atoms is selected from numbers capable of geometrically forming a spherical structure). atoms is a spherical carbon C _n that binds to the globular made to constitute a cluster (molecular assembly), _{respectively, C 60, C 70, C} 74, C 76, C 78, C 80, C 82, C _It is represented as ₈₄ mag.

For example, C ₆₀ has a polyhedral structure called “truncated icosahedron” in which all vertices of the icosahedron are cut off to form a regular pentagon, as schematically illustrated in FIG. 32, and further illustrated in FIG. As described above, this polyhedron is a cluster in which all 60 vertices are substituted with carbon atoms C, and has a molecular structure of an official soccer ball type. Similarly, C ₇₀ , C ₇₆ , C _{84 and the} like also have a so-called rugby ball type molecular structure.

These fullerenes, their use various studies have been conducted on such, for example, since the material doped with an alkali metal has been confirmed to exhibit superconductivity to C ₆₀ fullerene, applications as an electronic material is actively studied ing.

However, although C ₆₀ fullerene film can be formed by a vacuum deposition method, such film is not conductive so high, also, there is uncertainty in order to have an absorption in the visible region, and the mechanical strength Also has the disadvantage of not being excellent.

  Fullerene is a compound consisting only of carbon, and can be easily vaporized by heating under vacuum. Therefore, a fullerene polymer (or multimer) can be obtained by giving sufficient energy to polymerize between fullerene molecules in the course of vapor deposition of this compound or in the state of a vapor deposited film.

Fullerene multimer consisting of such carbon only, in addition to the use of C ₆₀ fullerene film described above, it can also be used more different applications, for example, carbon protective film, a carbon separator film, sensor, Application to battery electrode material or the like Alternatively, a diamond film or the like can be obtained.

  Conventionally, to obtain such a carbon thin film, a method by pyrolysis of a hydrocarbon compound is generally used, and a carbon film obtained by such a method is generally an amorphous carbon film. Therefore, there has been no method for producing a carbon film that retains the properties of the starting material as a carbon source.

  Further, as a method of manufacturing a carbon film using a carbon source, a carbon sputtering method is also known, but the shape of the carbon film obtained by this method is also irregular, and at the time of sputtering, a method for evaporating carbon is used. High energy was needed.

  An object of the present invention is to provide a fullerene polymer (or multimer) which retains the excellent physical properties of fullerene as a carbon source and is useful for various uses, and a film comprising the fullerene polymer. .

That is, the present invention is obtained by polymerizing a plurality of molecules of fullerene represented by C _n (where n is 60 or 70 capable of forming a spherical compound geometrically; hereinafter the same), Structures d, e, f, g, and h, in which at least one constituent carbon atom of the fullerene molecule is partially missing and the plurality of molecules are directly bonded to each other via a carbon atom adjacent to the missing site. , I or j, and a fullerene polymer film comprising the fullerene polymer.

  The fullerene polymer (or multimer) according to the present invention has a structure in which a plurality of fullerene molecules are directly bonded via a carbon atom adjacent to a site where a constituent carbon atom of at least one fullerene molecule is missing. It is a polymer that retains the structure of fullerene as a carbon source to some extent or sufficiently. Therefore, the fullerene polymer exhibits characteristics such as high electrical conductivity (electrical conductivity), excellent transparency, and high mechanical strength, while maintaining excellent physical properties inherent to fullerene.

The fullerene polymer according to the present invention must have a structure in which a plurality of fullerene molecules are bonded with high symmetry, such as a polymer between two molecules, in order to maintain the structure of the fullerene and exhibit a relatively stable polymer structure. Then, it is desirable to have a symmetry of D _2h .

Further, in order to reproducibly and reliably exhibit the above properties or characteristics, as a plurality of fullerene molecules of the same type in all the same number of carbon atoms to form a polymer (e.g., from only C _60, or only C ₇₀ Is desirable.

  The fullerene polymer (or multimer) according to the present invention is useful for a protective film or the like as a fullerene polymer film containing the fullerene polymer as a main component, and as a fullerene polymer-containing material containing the fullerene polymer. Useful for catalysts and the like.

Further, the present invention is to polymerize while retaining the structure of fullerene as a carbon source as described above, to obtain a fullerene polymer and a fullerene polymer film according to the present invention consisting of only carbon at relatively low energy, Having a process of applying polymerization energy (for example, plasma, light, electron beam, X-ray, or heat) to a plurality of molecules of fullerene represented by C _n in a gas phase and / or a solid state to polymerize the molecules. It is desirable to manufacture by a method.

  Also in this production method, for the same reason as described above, it is desirable to use a plurality of molecules of the fullerene purified so as to be of the same type having the same number of carbon atoms.

  Hereinafter, examples of the present invention will be described.

<Production of fullerene polymer>
First, an argon plasma method as a method for obtaining a fullerene polymer (or a multimer) based on the present invention will be described.

  FIG. 23 shows an external electrode type capacitively coupled plasma polymerization apparatus used in this example. This plasma polymerization apparatus has a reactor 1 having a capacity of about 20 liters, and the reactor 1 is provided with gas supply pipes 2 and 3. At the bottom of the reactor 1, an exhaust port 4 including an oil diffusion pump 40, rotary pumps 41 and 42, liquid nitrogen traps 43 and 44, and connected to a vacuum exhaust system is provided.

  On the upper part of the reactor 1, plasma generating electrodes 5 and 5 ′ are installed outside the reactor 1 at an interval of 3.5 cm, and are connected to a plasma power source 6 via an impedance matching device 7. I have. In the reactor 1, a molybdenum boat 8 for fullerene sublimation and a sample substrate 9 are installed facing each other with a space of 7 cm, and a DC power supply 10 is connected to the molybdenum boat 8.

  The output of the plasma power supply 6 is a radio wave of 13.56 MHz AC and has a maximum output of 150 W. Here, argon plasma is generated in a constant flow rate system of argon gas set at 13.5 Pascal at 25 W, 50 W, and 100 W, and fullerene put in a molybdenum boat 8 is sublimated at several 100 ° C. in this plasma. Plasma polymerization is performed to deposit a fullerene plasma polymer on the substrate 9. The film thickness during the polymerization is continuously monitored by the sensor 11. Argon gas and nitrogen gas are used as carrier gas.

Fullerene as a raw material is prepared as follows. That is, first, carbon powder generated by arc discharge between graphite electrodes by a known method is extracted with a solvent such as toluene or carbon disulfide, or C ₆₀ / C ₇₀ (C ₆₀ and C ₇₀ is extracted by direct sublimation method). Of C ₆₀ : C ₇₀ gives about 9: 1). Next, the C ₆₀ / C ₇₀ is developed by a column method using, for example, toluene + hexane (toluene 1 + hexane 9) in an activated alumina column to separate and purify C ₆₀ and C ₇₀ .

In this example, it is characteristic that not C ₆₀ / C ₇₀ but only C _{60 of} the same type and the same type or only C ₇₀ is used as the sublimation source.

  FIG. 24 shows a parallel plate electrode type capacitively coupled plasma polymerization apparatus. This plasma polymerization apparatus also has a reactor 11 having a capacity of about 20 liters similarly to the external electrode type capacitively coupled plasma polymerization apparatus of FIG. 23, and the reactor 11 is provided with gas supply pipes 12 and 13. ing. Further, at the bottom of the reactor 11, an exhaust port 14, which includes an oil diffusion pump 50, rotary pumps 51 and 52, liquid nitrogen traps 53 and 54, and is connected to a vacuum exhaust system, is provided.

  In the reactor 11, plasma generating electrodes 15 and 15 ′ are installed in parallel at a distance of 10 cm, and one of the electrodes 15 is connected to a plasma power supply 16 via an impedance matching device 17. Further, argon gas is introduced from the upper electrode 15 between the electrodes 15-15 'in a shower shape.

Further, a molybdenum boat 18 for C ₆₀ or C ₇₀ fullerene sublimation and a sample substrate 19 are installed facing each other at a distance of 7 cm between the electrodes 15 and 15 ′. 20 are connected.

  Also in this apparatus, the film thickness during polymerization is continuously monitored by the sensor 21, and the DC power supply 20 is the same as the DC power supply 10 of the polymerization apparatus shown in FIG.

<Structural analysis of fullerene polymer>
In order to clarify the structure of the fullerene polymer (multimer) grown on the substrate as described above, a calculation based on the semi-empirical molecular orbital method was performed. This includes MNDO / AM-1 by JJPStewart. The method (QCPE Program 455, 1983, Ver. 5.01) was used.

For the C ₆₀ multimer, a carbon source consisting of only purified C ₆₀ fullerene was subjected to plasma polymerization using the apparatus shown in FIG. 23, for example, to synthesize a C ₆₀ plasma polymer. FIG. 1 shows a mass distribution of a C ₆₀ plasma polymer (C ₆₀ multimer) measured by a time-of-flight method by laser desorption ionization called TOFMAS (Time-of-flight mass spectroscopy). .

In this figure 1, m / z (m is the mass, z is the charge) shows a wide range of sequence values, although the numbers of the spectrum in the figure represents the number of the fullerene molecules constituting the multimer, 2 C ₆₀ It is evident that multimers ranging from about 10 to about 14 mer are formed.

Fullerene represented by C ₆₀ is a spherical compound having 60 carbon atoms as shown in FIGS. 32 and 33, and has 30 equivalent conjugated double bond bonds. As an initial process of plasma polymerization, it is considered that the C ₆₀ compound excited by plasma starts dimerization from an excited triplet state at a double bond site. investigated.

That is, FIGS. 2, 3, 4, and 5 show dimer structures A, B, C, and D, respectively, which are considered to be possible. Each of these structures shows information about the carbon atom involved in the addition between 6 membered ring of the addition reaction of C ₆₀ in the figures by solid circles, carbon - shows the carbon-carbon addition bond by a broken line. These are described in the Journal of Applied Physics, Vol. 74, No. 9 (1993), 5790-5798, Journal of Physical Chemistry, Vol. 98 (1994), 2555 by the present inventors.

As for C ₆₀ 2 dimer structures to D, in Table 1 below shows the calculated value of the generated reaction heat from C ₆₀ by MNDO / AM-1 method (heat of reaction).

This indicates that only the C ₆₀ dimer of structure A is specifically stable because it is generated by an exothermic reaction (it is an endothermic reaction), and that the [2 + 2] Cycloaddition reaction is occurring, that is, cyclohexatrienyl It is suggested that _C60 molecules are linked by a 1,2-cycle bond added to the site. In structure B, the dimer is axisymmetric, and in structure C, the dimer is rotationally symmetric.

However, in the above-described method for producing a C ₆₀ multimer, the reaction further proceeds because the argon plasma is intermittently irradiated. Thus, from the data of FIG. 6 showing the spectra of the C ₆₀ dimer and the region in the vicinity thereof shown in FIG. 1, the peak intensity is the highest at C ₅₈ 2 where two carbon atoms are missing from C _60. It can be seen that the peak intensity is C ₁₁₆ corresponding to the _monomer and then decreases to C ₁₁₄ , C ₁₁₈ , C ₁₁₂ . In addition, C ₁₂₂ corresponding to a C ₆₁ dimer obtained by adding one carbon atom to C ₆₀ also exists.

Thus, the actual primary structure of C ₆₀ 2 dimer are C _116, C _118, etc., it is suggested that fragmentation C ₂ is occurring. It is considered that the following three processes (1), (2), and (3) are possible to generate _C116 , _{C118, and the} like.

(1) The four-membered ring (cyclobutane ring) structure of the compound such as structure A in FIG. 2 has a large structural distortion, carbon is eliminated from this part from the excited state of this compound, and C ₁₁₆ and C _{116 are} recombined. Process where ₁₁₈ mag occurs.

(2) Stone-Wales transition as Murrey et al points out, occurs desorbed from the excited state of the two carbon atoms of C ₆₀ is, process C _116, C _118, etc. by recombination occurs (RL Murrey, et, al., Nature 356 (1993) 426).

(3) M.P. Polycation generated from the excited state of C ₆₀ as Fieber-Erdman et al pointed out, the process (M. Fieber-Erdman et to C _116, C ₁₁₈ and the like occur by recombination and fragmentation carbon from this state, al. , Z. Phys. D 26 (1993) 308).

Although it is difficult to clearly determine which of these processes is the main process, if a compound such as the structure A in FIG. 2 occurs as an initial process, the process (1) may be performed. Considered to be major. Since the dimer of the structure A is stable as shown in Table 1 above, it is considered that the dimer is predominantly generated in the initial stage as compared with the other structures B, C, and D. This is due to the following mechanism. It is considered that C changes to C ₁₁₆ , C ₁₁₈ and so on.

That is, in the cyclobutane ring of the C ₆₀ dimer of structure A shown in FIG. separated carbon atoms removed, the carbon atoms of both the fullerene molecules represented by white circles and × in the figure are recombined, C ₁₁₈ structure a shown in FIG. 7 is thought to occur, for example.

C ₁₁₈ of the structure b shown in FIG. 8, the cyclobutane ring of FIG. 2 2-position and 4-position carbon atoms are eliminated, in which one of the fullerene molecules is inverted relative to the other, and recombine. Other, by desorption position and recombination sites of the carbon atoms in the cyclobutane ring, occur structure c shown in FIG. 9, also, the structure d shown in FIG. 10 as C _116, structure e shown in FIG. 11, FIG. 12 The structures f shown respectively result.

Although these structures a to f are shown as fullerene dimers, similar elimination and recombination of carbon atoms occur at other double bond carbon-carbon bond positions in the fullerene molecule. Also, polymers of trimers or more are produced. That is, the fullerene multimer according to the present invention may be formed only by the C _n polymerized structure. In this case, however, it is considered that the C _n polymerized structure is spread in a network by covalent bonds. When the polymer has a partially polymerized C _n structure, it is presumed that unpolymerized portions are bonded to each other by van der Waals force. In the film or material of the fullerene multimers, with the above-mentioned C _n polymerized structure, C _n single molecules of C ₆₀ or the like as a raw material may be mixed.

Table 2 below shows the heat of formation of the fullerene multimers of each of the above structures a to f.
formation). Here, the reason for not being indicated by the heat of formation reaction is, for example, that two C ₆₀ to C ₁₁₈
Effect on the reaction by C ₂ occur simultaneously when or C ₁₁₆ is generated is because it is unknown.

Value per unit of carbon atoms of the generated heat of fullerene multimers shown in Table 2: ΔH f _{o /} ^C are structurally stable for towards C ₁₁₈ and C ₁₁₆ in C ₁₁₆ is small heat of formation, experimental I support the results.

Furthermore, most stable C ₁₁₆ is to be a C ₁₁₆ of structure f (see FIG. 12) is suggested, rotating high symmetry of this structure is D _2h (i.e., about the axis of the direction perpendicular to the long axis which has symmetry), four cross-link bonds CL represents a double bond properties, moreover Kekule structure had originally C ₆₀ is also stored. Therefore, it is considered that _C116, which was the most significant dimer among the dimer peaks in FIG. 6, has the structure of f. In addition, such a binding mode is considered to be the main process of multimer formation.

For the C ₇₀ multimer, a carbon source consisting of only purified C ₇₀ fullerene was subjected to plasma polymerization using the above-described apparatus shown in FIG. 23 to synthesize a C ₇₀ plasma polymer. Figure 13 shows the mass distribution of the polymer of C ₇₀ obtained.

As is clear from FIG. 13, it is clear that multimers ranging from dimers to 10-mers of C ₇₀ are produced.

Figure 14 shows the molecular structure of C _70. C ₇₀ has four types of conjugated double bond shown by thick lines. In considering a dimer of the compound, based on the results of the C ₆₀ as described above, it is considered that only [2 + 2] Cycloaddition is stable, was investigated this.

The Figures 15-18 show a dimer of C ₇₀ by [2 + 2] Cycloaddition (in each figure thereof, on the upper surface and the front of the dimer is shown below). That is, FIG. 15 shows the structure E, FIG. 16 shows the structure F, FIG. 17 shows the structure G, and FIG. 18 shows the C ₇₀ dimer of the structure H. These are the bonding positions of carbon (position (1) in FIG. 14). To (7)).

Among these, structures F to H have antisymmetric (antisymmetric) structural isomers, which are represented by F ′, G ′, and H ′. Structure E, F, G, H and F ', G', were determined generation reaction heat from C ₇₀ for H '. Table 3 below shows the results.

This result, C ₇₀ 2 dimer structures H and H 'are suggested to be stable, dimer structure bonds 1-2 and 3-4 of the C ₇₀ (which, in the display of FIG. 14 (2) - (2), (1) - (1) it is a dimer of C ₇₀ by [2 + 2] Cycloaddition of coupling) between is indicated. The values in this table indicate that the 1-2 and 3-4 bonds of C ₇₀ have almost the same chemical reactivity as the conjugated double bond of C ₆₀ , and the physical properties of C both ends of the molecular axis ₇₀ is seen to be close to C _60.

Incidentally, a dimer of the compounds are also suggested a process involving elimination of 4 carbons is most important (see FIG. 6), the dimer of C ₇₀ in FIGS. 15 to 18 FIGS. 19, 20, 21, and 22 show structures in which four carbons forming a four-membered ring are eliminated and recombined, respectively. These dimers have different structures depending on the positions of carbon desorption and recombination. The heats of formation of these dimers per unit carbon atom are shown in Table 4 below.

Each of the C ₁₃₆ molecules of the structures g, h, i, and j shown in FIGS. 19, 20, 21, and 22 corresponds to the structures E, F, G, and G shown in FIGS. 15, 16, 17, and 18, respectively. It corresponds to the one obtained by removing the four-membered ring carbon atom of each _C140 molecule of H. The results in Table 4 show that the most stable dimer, structure j in FIG. 22 (C ₁₃₆ molecule derived from C ₁₄₀ molecule in structure H), is the most structurally stable.

  As is clear from the above description, based on the present invention, polymerization is performed while maintaining the structure of fullerene as a carbon source to some extent or sufficiently, and a relatively low energy is used to obtain a stable fullerene multimer composed of only carbon. It is possible.

<Effect of carbon source on physical properties>
However, according to the present invention, fullerene as a carbon source vaporizes or sublimes at a temperature of several hundred degrees Celsius, and there is no other such material as a carbon source. Further, since the consist only of the same type of C ₆₀ alone or C ₇₀ at the same number of carbon atoms, is obtained fullerene multimeric stable structure that securely holds the characteristics possessed by the fullerene (especially, the structure of FIG. 12 f, Structure j) of FIG. 22 can be generated with good reproducibility.

In contrast, C ₆₀ and C _70, for example from about 9: 1 when the mixture was used as a carbon source, C ₆₀ multimers and C ₇₀ multimers, the multimers of between C60-C ₇₀ are mixed further optionally to be, only C _60, so that the multimers having intermediate properties of the polymer of only C ₇₀ is obtained.

  Among various physical properties of the fullerene multimer, for example, the water resistance of the fullerene multimer according to the present invention is good in terms of water resistance as a protective film.

<Preparation of fullerene polymer thin film and evaluation of properties>
Using the plasma polymerization apparatus shown in FIG. 23 or FIG. 24 described above, to prepare a sample 32 was deposited to a thickness of 1000Å a plasma polymer film 31 of C ₆₀ or C ₇₀ fullerene on the substrate 39 shown in FIG. 25. That is, gold comb electrodes 30 and 30 'are formed on the surface of the glass substrate 39 so as to face each other so that the comb teeth mesh with each other, and a fullerene plasma polymer film 31 is formed to cover these comb teeth. did. In addition, this plasma polymer film actually covers the comb-tooth portions of the comb-shaped electrodes 30, 30 'as shown by a dashed line in FIG. 25, but is shown only between the comb-tooth portions in the drawing. I have.

  Therefore, as shown in FIG. 25, the plasma polymer film 31 operates as a resistor between the comb-teeth portions of the comb-shaped electrodes 30 and 30 ', and flows a current at a constant voltage between the comb-shaped electrodes 30-30'. By measuring the current value (resistance value), the conductivity can be measured from the following equation. The interval d between the comb teeth of the comb electrodes 30 and 30 'is 1 mm, and the electrode length L is 110 mm.

σ：導電率
Ｒ：測定抵抗値
Ｌ：電極長
ｅ：試料厚み

σ: conductivity R: measured resistance L: electrode length e: sample thickness

  Therefore, the conductivity of the sample manufactured as described above was measured using a voltage-current characteristic measuring device shown in FIG. This voltage-current characteristic measuring device is computer-controlled, has a heating element 61 in a copper Faraday cage type cell 60, and has a sample holder 62 on the heating element 61. The lid is closed by a lid 65 having vacuum valves 63 and 64.

  At predetermined positions of the cell 60, coaxial cable plugs 66 and 67 penetrating the cell 60 are provided, and the comb-teeth electrodes 30-30 'formed on the surface of the glass substrate 39 via these coaxial cable plugs. The voltage-current characteristics between them are measured. The temperature inside the cell 60 is monitored by a thermocouple 68.

As a result, changes in the conductivity of the sample was deposited at a plasma output range of 25～100W (e.g. C ₆₀ plasma polymer film only C ₆₀ as the raw material) was not observed. Table 5 below shows, as typical values, the conductivity of the above-mentioned plasma polymer film in the atmosphere and in a vacuum when subjected to plasma polymerization at 100 W. The table 5, but also shows the conductivity of the C ₆₀ vapor-deposited film, it can be seen that the conductivity of the plasma polymer film according to the present invention is improved.

＊ J. Mort et al., Chem. Phys. Lett., 186(2,3), 284-286(1991)

* J. Mort et al., Chem. Phys. Lett., 186 (2,3), 284-286 (1991)

Also, it is shown respectively UV~ visible absorption spectra of C ₆₀ plasma polymer film having a thickness of 1000Å produced by the above method, and a UV~ visible absorption spectrum of the deposited film in FIG. When converted from the spectral data, the C ₆₀ plasma polymer film, absorption than 1000Å per deposited film has decreased by 27% in 450 nm, the light transmittance is increased to 52% from 20%.

We also examined the adhesive strength and scratch resistance of the C ₆₀ plasma polymer film produced, the adhesion strength to the glass substrate than the deposited film, scratch strength it is confirmed that clearly superior.

Figure 28 shows the infrared absorption spectrum of the C ₆₀ plasma polymer film produced in this example. Absorption peaks of 1,000 to ^-1 is suggested crosslinked C-C bonds, since the absorption peak of 1028cm ^-1 is characteristic of the above-mentioned cyclobutane structure (see FIG. 2), C ₆₀ plasma polymer film is mainly considered that C _n between molecules by 1,2 cycles addition binding cyclohexanol satori enyl sites each other on the fullerene is generated through once the state polymerized.

Figure 29 shows an X-ray diffraction spectrum of the C ₆₀ plasma polymer film produced in this example. According to this, for example, annual of JPS fall by Takada et al., (1991) 29pBPS23 no diffraction peak showing the structure regularity by distinctive epitaxial crystal of C ₆₀ fullerene, as reported in, broad Only a diffraction peak (estimated as a diffraction peak derived from the glass of the substrate) is observed, which indicates that the structure of this film is amorphous.

<Use of fullerene polymer>
Film or material fullerene multimers according to the present invention and which mainly includes the presence of C _n polymerized structure described above, this is by distributed in amorphous, conductivity higher without electrostatically charged It is a thin film having excellent transparency and high mechanical strength, and is useful as a material having a wide range of applications. In particular, the organic semiconductor thin film has a conductivity of 10 ⁻⁶ S / cm or more, which is equivalent to 10 ⁸ times that of the vapor-deposited film, and has a transmittance of visible light having a wavelength of 450 nm of about 2. It is 52% or more per 1000 ° corresponding to 7 times.

  Therefore, this fullerene polymer film is used for a surface protection film of a magnetic recording medium such as a magnetic tape or a magnetic disk, a surface protection film of an optical pickup side of a magneto-optical disk device, etc. It can be used widely. Next, an application example will be described.

Carbon film The fullerene multimer obtained as described above is structurally stable because it preserves a conjugated structure. Therefore, the film of the fullerene multimer can almost completely prevent invasion of water, oxygen, acid, metal and the like, and has physical and chemical stability. Therefore, as a carbon film, a recording medium such as a magnetic tape or a disk is used. It is useful for protective films, lubricating films, optical materials, sensors, etc.

FIG. 30 illustrates a method for forming such a carbon protective film. In a plasma polymerization apparatus having basically the same configuration as the plasma polymerization apparatus described with reference to FIG. While being continuously or intermittently fed from the roll 70, fullerene (C ₆₀ or C ₇₀ ) is sublimated by argon plasma, deposited on the film substrate 9, and further taken up by the take-up roll 71. The rolls 70 and 71 can be arranged outside the reactor 1.

  The fullerene polymer film thus formed can be formed on the surface of the magnetic layer 80 as a surface protective film 81 of a magnetic recording medium such as a magnetic tape, as shown in FIG. In this case, in the method shown in FIG. 30, a substrate 9 in which a magnetic layer 80 is already formed on a base film 82 by a known method is used. Then, a lubricant layer 83 such as a fatty acid ester is further applied to the surface of the fullerene multimer film 81 formed on the magnetic layer 80 to improve the rubbing property on the magnetic head.

Other applications In general, fullerene has a high electronegativity and a high addition reactivity, so that other molecules or metals coexist in the process of the above polymerization method, and by forming a fullerene multimer film containing these, It is possible to control physical properties such as conductivity. This can be applied to electrode materials and the like.

  Further, with respect to fullerene multimers having a small molecular weight, application to catalysts, dyes, pigments and the like can be considered.

  Although the embodiments of the present invention have been described above, the above-described embodiments can be variously modified based on the technical idea of the present invention.

  For example, the above-described plasma polymerization conditions (plasma generation conditions, sublimation conditions, types of gas used, pressure, and the structure of the vacuum apparatus, etc.) may be variously changed.

As for the carbon source, the carbon number n of the spherical carbons C _n is preferably 60 and / or 70, but for example, a spherical carbon having a carbon number n of 76, 84, etc. has the same characteristics as a plasma having the same characteristics. It is possible to obtain a polymer film. C ₆₀ / C ₇₀ (a mixture of C ₆₀ and C ₇₀ ) is preferred in view of the availability of raw materials.

  With respect to the plasma polymerization conditions, various types of known discharge methods such as direct current discharge, low frequency discharge, high frequency discharge, and microwave discharge can be adopted as the discharge method of plasma generation. Electrode method, external electrode method, waveguide method, capacitive coupling type, inductive coupling type, electrodeless oscillation type and the like can be selected.

The plasma polymerization may be performed in a single atmosphere of spherical carbons composed of C ₆₀ and C ₇₀ , but may be used in combination with a carrier gas from the viewpoint of improving the uniformity and stability of the plasma. As the carrier gas, any of those generally used in plasma polymerization can be used, and examples thereof include argon, nitrogen, and helium.

  There is no problem in polymerization as long as the discharge condition is a range in which Paschen's law indicating the relationship between the gas pressure, the distance between the electrodes, and the voltage is satisfied in DC discharge, and a dischargeable range in AC discharge. The gas pressure is preferably below 20 Pascal.

  The fullerene polymer film according to the present invention may be formed directly by plasma polymerization. However, the film formed by plasma polymerization may be dissolved in an appropriate solvent (for example, benzene), and the desired film may be formed by coating the film. It can be finished in thickness, shape, etc.

  In addition, the fullerene multimer according to the present invention can be synthesized by applying a predetermined energy in the gaseous phase or solid phase state of fullerene molecules, or both, in addition to the above-described plasma polymerization. In addition to the above-described plasma, for example, light (ultraviolet light or the like), electron beam, X-ray, heat, or the like can be applied. In the solid state, for example, after a fullerene vapor-deposited film is formed, it can be polymerized by applying ultraviolet energy thereto.

  The fullerene polymer (or multimer) and the fullerene polymer film according to the present invention have high electrical conductivity (electrical conductivity), excellent transparency, and high mechanical strength while maintaining the excellent physical properties inherent to fullerene. It shows the characteristic of high.

A Time-of-Flight mass spectrometry spectrum of fullerene multimers obtained by plasma polymerization of fullerene C ₆₀ molecules on the basis of the present invention. Is a schematic view showing the dimer structure of C ₆₀ molecules is thought to occur in the process of generating the fullerene multimers. It is a schematic view showing another dimeric structure of C ₆₀ molecules is thought to occur in the process of generating the fullerene multimers. It is a schematic view showing another dimeric structure of C ₆₀ molecules is thought to occur in the process of generating the fullerene multimers. It is a schematic view showing another dimeric structure of C ₆₀ molecules is thought to occur in the process of generating the fullerene multimers. FIG. 4 is an enlarged spectrum diagram of a mass distribution of a dimer portion in a time-of-flight mass spectrometry spectrum of a fullerene multimer obtained by plasma polymerization of C ₆₀ molecules. Is a schematic diagram showing the molecular structure of what is expected confirmed C ₁₁₈ molecular mass distribution of the dimeric portion of the C ₆₀ molecules fullerene multimers obtained by plasma polymerization of. It is a schematic view showing another molecular structure of the expected as the C ₁₁₈ molecules identified in mass distribution of the dimeric portion of the C ₆₀ molecules fullerene multimers obtained by plasma polymerization of. It is a schematic view showing another molecular structure of the expected as the C ₁₁₈ molecules identified in mass distribution of the dimeric portion of the C ₆₀ molecules fullerene multimers obtained by plasma polymerization of. Is a schematic diagram showing the molecular structure of what is expected confirmed C ₁₁₆ molecular mass distribution of the dimeric portion of the C ₆₀ molecules fullerene multimers obtained by plasma polymerization of. It is a schematic view showing another molecular structure of the expected as the C ₁₁₆ molecules identified in mass distribution of the dimeric portion of the C ₆₀ molecules fullerene multimers obtained by plasma polymerization of. It is a schematic view showing another molecular structure of the expected as the C ₁₁₆ molecules identified in mass distribution of the dimeric portion of the C ₆₀ molecules fullerene multimers obtained by plasma polymerization of. FIG. 4 is a Time-of-Flight mass spectrometry spectrum of a fullerene multimer obtained by plasma polymerization of C ₇₀ molecules. It is the schematic which shows the molecular structure of _C70 molecule, and four types of conjugated double bonds. Is a schematic view showing the dimer structure of C ₇₀ molecules is thought to occur in the process of generating the fullerene multimers. It is a schematic view showing another dimeric structure of C ₇₀ molecules is thought to occur in the process of generating the fullerene multimers. It is a schematic view showing another dimeric structure of C ₇₀ molecules is thought to occur in the process of generating the fullerene multimers. It is a schematic view showing another dimeric structure of C ₇₀ molecules is thought to occur in the process of generating the fullerene multimers. It is a schematic diagram showing the molecular structure of what is predicted to C ₁₃₆ molecules identified in mass distribution of the dimeric portions of the fullerene multimers obtained by plasma polymerization of C ₇₀ molecules. It is a schematic view showing another molecular structure of the expected as the C ₁₃₆ molecules identified in mass distribution of the dimeric portion of the C ₇₀ molecules of the plasma polymerization resulting fullerene multimers. It is a schematic view showing another molecular structure of the expected as the C ₁₃₆ molecules identified in mass distribution of the dimeric portion of the C ₇₀ molecules of the plasma polymerization resulting fullerene multimers. It is a schematic view showing another molecular structure of the expected as the C ₁₃₆ molecules identified in mass distribution of the dimeric portion of the C ₇₀ molecules of the plasma polymerization resulting fullerene multimers. FIG. 1 is a schematic cross-sectional view showing one configuration example of a plasma polymerization apparatus that can be used in the present invention. It is a schematic sectional drawing which shows the other example of a structure of the plasma polymerization apparatus which can be used for this invention. 1 is a schematic plan view of a measurement sample on which a plasma polymer film (multimer film) according to the present invention is formed and an enlarged cross-sectional view of a part thereof. It is the schematic cross section of the cell for electric conductivity measurement of the same measurement sample, and its longitudinal section. FIG. 3 is an ultraviolet-visible absorption spectrum diagram showing a comparative example of a formed thin film. FIG. 3 is an infrared absorption spectrum of the plasma polymer film according to the present invention. 1 is an X-ray diffraction spectrum of a plasma polymer film according to the present invention. 1 is a schematic sectional view of a plasma polymerization apparatus showing an example of a method for producing a product having a plasma polymer film according to the present invention. FIG. 2 is a schematic enlarged sectional view of a magnetic recording medium which is an example of the product. It is a schematic diagram showing a truncated icosahedron structure of C ₆₀ fullerene. FIG. 3 is a schematic diagram showing a bonding state between carbons in C ₆₀ fullerene.

Explanation of reference numerals

1, 11: reactor, 5, 5 ', 15, 15': electrode for plasma generation,
6, 16 ... plasma power supply,
8,18 ... molybdenum boat (C ₆₀ or housing the C ₇₀ fullerene),
9, 19, 39 ... substrate, 10, 20 ... sublimation voltage source, 30, 30 '... electrode,
31, 81: fullerene polymer film (polymer film),
C ₆₀ , C ₇₀ , C _n ... spherical carbons (fullerene),
C ₁₁₈ , C ₁₁₆ , C ₁₃₆ ... fullerene polymer (polymer)

Claims (3)

It is obtained by polymerizing a plurality of fullerene molecules represented by C _n (where n is 60 or 70 capable of forming a geometrically spherical compound), and has the following structure d, e, f, g, Fullerene polymer consisting of h, i or j.

  The fullerene polymer according to claim 1, wherein the fullerene polymer is obtained by plasma polymerization.   A fullerene polymer film comprising the fullerene polymer according to claim 1.

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