JP2008056864A - Fullerene polymer composite and its production process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fullerene-containing polymer material without chemical modification of fullerene, and a slightly soluble fullerene homogenously and massively dispersed in a synthetic polymer without phase separation, and a process for its production. <P>SOLUTION: The composite of the synthetic polymer and fullerene, and its production are disclosed. Particularly, the fullerene/polymer composite clathrating fullerene in a syndiotactic polymethacrylate polymer or a spiral conformation of the syndiotactic polymethacrylate polymer, and its production process. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composite of a synthetic polymer and fullerene and a method for producing the same. In particular, the present invention relates to a fullerene polymer composite in which fullerene is included in a helical conformation of a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer, and a method for producing the same.

Fullerene is a chemically and thermally stable spherical molecule, and has features such as easy absorption of light energy, good electron acceptability, and high radical scavenging ability. Many application fields as the core material of nanotechnology, such as energy device field utilizing electron mobility, electronic material field utilizing photosensitivity, and application to materials utilizing thermal and mechanical properties by addition to resin and film The application to is active.
When fullerene is used as an industrial material, in order to disperse fullerene, it is important to combine it with a polymer material, and many studies have been conducted. For example, it has been reported that electrical properties, optical properties, magnetic properties, mechanical properties, thermal stability, and the like change dramatically by doping fullerenes into various synthetic polymers (see Non-Patent Document 1). ).

However, fullerene has a strong cohesive force. Generally, just mixing fullerene and polymer will cause phase separation in the polymer to form amorphous aggregates, which makes it difficult to blend at high concentrations. Yes, the excellent electrical, optical, and magnetic properties of fullerene cannot be utilized to a high degree. Therefore, in order to dissolve fullerenes at a high concentration and arrange them in a regular structure, chemical modification of fullerenes and chemical bonding to polymers have been studied (see Non-Patent Document 2). For example, a method of introducing a group having an unsaturated bond such as a (meth) acryloyl group into fullerene and copolymerizing the group (see Patent Documents 1 and 2), a polymer compound having a fullerene compound and a hetero ring in the side chain And a Diels-Alder reaction to obtain a fullerene-containing polymer compound (see Patent Document 3), a polymer chain segment of polyethylene glycol as a core part, and a polymer chain segment of poly (alkylaminoethyl methacrylate) as a shell part A method of encapsulating fullerene in fine particles based on a block copolymer (see Patent Document 4), a stereoregular polymer selected from polythiophene, polypyrrole or polyfuran, an ester group, an imino group, an alkyl group, an aralkyl group, a thiophenyl group Less functional groups selected from A photoelectric conversion element having a solid layer made of a charge transporting heterocyclic polymer containing a modified fullerene modified with a group containing at least one group (see Patent Document 5), a polymerizable monomer A fullerene copolymer obtained by bonding an alkylated fullerene to a residue and copolymerizing it (see Patent Document 6) has been reported.
These methods attempt to immobilize fullerenes in a polymer by chemical bonding or the like, but this requires a complicated chemical reaction, which inevitably increases costs. .

In recent years, it has been reported that schizophyllan, which is a polymer derived from natural products, incorporates fullerene or the like inside the helical structure (see Non-Patent Document 3). However, there is no mention of the mechanism by which it is taken up and whether fullerenes can be taken in other materials, and the method of Non-Patent Document 3 is a polymer derived from natural products. The natural polymer has problems in processability and stability, and there are many restrictions on its application as an industrial material.
On the other hand, syndiotactic polymethyl methacrylate (hereinafter referred to as st-PMMA) takes a loosely wound helical structure of about 18/1 in toluene, and toluene, acetone, etc. are in the space of about 1 nm in diameter inside. It is known that a low molecular weight solvent molecule is incorporated to form a helical structure and gel and crystallize. It has also been reported that when the solvent is removed from this st-PMMA-solvent complex, st-PMMA cannot retain the helical structure, the crystal structure is broken, and becomes amorphous (see Non-Patent Documents 4 and 5).

JP-A-8-283199 JP-A-8-239209 JP-A-9-188726 JP 2005-1113090 A JP 2005-116617 A JP 2006-56966 A C. Wang, et al., Prog. Polym. Sci. 29, 1079-1141, 2004 Ball, Z. T .; Sivula, K .; Frechet, J. M. J., Macromolecules 2006, 39, 70-72. Ikeda, Ito et al., Proceedings of the 55th Annual Meeting of Polymer Science, page 1888. Kusuyama, H .; Takase, M., et al, Polymer 1982, 23, 1256-1258. Kusuyama, H .; Miyamoto, N., et al., Polymer 1983, 24, 119-122.

  The present invention provides a fullerene-containing polymer material in which a poorly soluble fullerene is dispersed uniformly and in a large amount in a synthetic polymer without chemically modifying the fullerene, and a method for producing the same. Furthermore, the present invention provides a fullerene-containing polymer material in which fullerenes are regularly arranged one-dimensionally in the direction of the molecular chain of the polymer, and a method for producing the same.

The present inventors have studied a method for forming a fullerene-containing polymer composite in which fullerene is contained in a polymer material. However, fullerene has a strong cohesive force, and fullerene is not chemically modified or subjected to surface treatment. It was extremely difficult to disperse a large amount in the polymer material alone. The inventors of the present invention have further studied diligently, and surprisingly, when syndiotactic polymethacrylate or syndiotactic polyacrylate and fullerene are mixed in a solvent, these polymer materials generate a large amount of fullerene. It has been found that a crystalline complex dispersed therein is formed. Furthermore, the present inventors have studied this mechanism. As a result, syndiotactic polymethacrylate polymers and syndiotactic polyacrylate polymers have a loose helical structure, and fullerenes are encapsulated inside the helical structure. It was found that a large amount of fullerene was stably dispersed.
That is, the present invention is based on the discovery that a large amount of fullerene can be contained in a synthetic polymer compound by including fullerene in the helical structure of a synthetic polymer compound having a helical structure. is there.
Accordingly, the present invention relates to a fullerene-containing polymer composite in which fullerene is included in a polymer compound having a helical structure, and more specifically, syndiotactic polymethacrylate polymer or syndiotactic. The present invention relates to a fullerene-containing polymer composite comprising a fullerene clathrated inside a polyacrylate polymer.
The present invention also provides a method for producing a fullerene-containing polymer composite comprising syndiotactic polymethacrylate-based polymer or syndiotactic polyacrylate-based polymer and fullerene dissolved in a common solvent and then removing the solvent. About.
Further, the present invention comprises dissolving fullerene, syndiotactic polymethacrylate-based polymer or syndiotactic polyacrylate-based polymer, and fullerene in different solvents, mixing them, and then removing the solvent. The present invention relates to a method for producing a fullerene-containing polymer composite.
The present invention also relates to an industrial product containing the above-described fullerene-containing polymer composite of the present invention.

The present invention will be described in detail as follows.
(1) A fullerene-containing polymer composite comprising a fullerene encapsulated in a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer.
(2) The fullerene-containing polymer composite according to (1), wherein the fullerene is included in a helical structure of a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer.
(3) The fullerene-containing polymer composite according to (1) or (2), wherein the syndiotactic polymethacrylate polymer is syndiotactic polymethyl methacrylate.
(4) The fullerene-containing polymer composite has a melting point different from each simple substance and / or a crystal structure different from each simple substance, described in any one of (1) to (3) above Fullerene-containing polymer composite.
(5) The fullerene-containing polymer composite according to any one of (1) to (4), wherein the fullerene content is 1% by weight or more.
(6) The fullerene-containing polymer composite according to any one of (1) to (5), wherein the fullerene is a fullerene having 60 or more carbon atoms.
(7) A method for producing a fullerene-containing polymer composite comprising dissolving a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer and a fullerene in a common solvent and then removing the solvent.
(8) A good solvent for a syndiotactic polymethacrylate-based polymer or a syndiotactic polyacrylate-based polymer, wherein the solvent of the polymer gels with time or temperature change. The method according to (7).
(9) Fullerene, syndiotactic polymethacrylate-based polymer or syndiotactic polyacrylate-based polymer, and fullerene are dissolved in different solvents, mixed together, and then the solvent is removed. A method for producing a molecular complex.
(10) The above (7), wherein the solvent or common solvent is at least one selected from the group consisting of toluene, 1,2-dichlorobenzene, chlorobenzene, bromobenzene, benzene, butyl acetate, and dimethylformamide, or a mixture thereof. -The method in any one of (9).
(11) An industrial product comprising a fullerene-containing polymer composite obtained by including a fullerene in a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer.

The present invention is characterized by the first discovery that fullerene is included in the helical structure of a synthetic polymer compound having a helical structure, and the fullerene is included in the helical structure. It has been found for the first time that a large amount of fullerene can be stably dispersed in the synthetic polymer compound, and a fullerene-containing polymer composite in which a large amount of fullerene is stably dispersed can be provided. is there.
Next, the present invention will be described more specifically based on the drawings.
FIG. 1 is a more detailed explanation of the method for producing a fullerene-containing polymer composite of the present invention using an example in which syndiotactic polymethyl methacrylate (hereinafter referred to as st-PMMA) is used as a polymer compound. is there. St-PMMA is added to a toluene solution of C60 fullerene (FIG. 1 (a)), heated and stirred, and then allowed to stand at room temperature to gel (FIG. 1 (b)). By centrifuging this gel, st-PMMA including C60 fullerene can be produced ((c) of FIG. 1). The lower part of FIG. 1C schematically shows the helical structure of st-PMMA enclosing C60 fullerene. Fullerenes are arranged linearly in a one-dimensional manner in a helical structure formed by a polymer compound.
Next, the present inventors examined how much fullerene was included in st-PMMA. FIG. 2 is a plot of the amount of C60 fullerene incorporated against the added amount of st-PMMA. A predetermined amount of st-PMMA was added to 1 mL of a C60 fullerene toluene solution (concentration 2 mg / mL) to cause gelation. The obtained gel was separated into a polymer part and a supernatant part by centrifugation, and the amount of C60 fullerene incorporated was calculated by quantifying the C60 fullerene remaining in the supernatant part with an ultraviolet-visible absorption spectrum, as shown in FIG. Plotted on a graph. From the graph of FIG. 2, it can be seen that when toluene is used as the solvent, about 10% by weight of fullerene can be incorporated.

Next, the obtained gel was examined.
A 1H-NMR spectrum (polymer concentration: 10 mg / mL, C60 fullerene concentration: 2 mg / mL) of a gel of st-PMMA-C60 fullerene prepared in deuterated toluene at 25 ° C. and 100 ° C. was measured. The result is shown in FIG. The signal indicated by * in FIG. 3A is derived from the solvent. In the homogeneous solution state at 100 ° C., the NMR signal of the polymer was observed, but when gelation occurred at 25 ° C. due to the temperature drop, the signal was not observed (see FIG. 3A).
Therefore, the present inventors plotted the signal intensity of the polymer against the temperature, and measured the gelation temperature. The NMR signal intensity (I) of the α-CH 3 group of the polymer at each temperature at the time of temperature increase and temperature decrease was measured, and the NMR signal intensity (I 0) at 110 ° C. in a homogeneous solution state in which gelation did not occur. Based on this, the ratio of the gelled st-PMMA unit was calculated by the following formula.
Percentage of gelled st-PMMA units = (1−I / I0)
The result is shown in FIG. In FIG. 3, the horizontal axis (B) indicates the temperature (° C.), and the vertical axis indicates the ratio of the proportion of the st-PMMA unit that is gelled. The left side of the graph (black in the original figure) shows the case of st-PMMA gelation without addition of C60 fullerene, and the right side (red in the original figure) shows the case of gelation of st-PMMA-C60 fullerene. Each black circle (●) indicates the measurement result when the temperature is raised, and the white circle (◯) indicates the measurement result when the temperature is lowered. As a result, it was found that the gel of st-PMMA-C60 fullerene was shifted to a higher temperature side by about 20 ° C. than the case where C60 fullerene was not added (see FIG. 3B). This indicates that the gel incorporating C60 fullerene is more stable than the st-PMMA gel incorporating toluene alone, and that C60 fullerene does not exist as a simple interstitial material. Show.

Next, a film of st-PMMA-C60 fullerene complex was prepared and observed.
The result of observing this film with an optical microscope is shown in FIG. 4 as a color photograph in place of the drawing. (A), (c), and (e) of FIG. 4 are optical micrographs, and (b) and (d) are polarization micrographs. 4A and 4B show the case of a st-PMMA film not containing C60 fullerene, and FIGS. 4C and 4D show the case of a film of st-PMMA-C60 fullerene complex. (E) shows the case where 4.8 wt% of C60 fullerene is added to isotactic polymethyl methacrylate (hereinafter referred to as it-PMMA). The scale bar of each photograph shows 200 μm.
As a result, in the film of st-PMMA-C60 fullerene complex, since the polymer and C60 fullerene form a complex, the solvent is removed even though the content of C60 fullerene is as high as 25.2% by weight. However, no phase separation was observed (see (c) of FIG. 4). In addition, when the film of the st-PMMA-C60 fullerene complex was observed with a polarizing microscope, birefringence was observed, indicating that the complex was crystallized (see FIG. 4D).
Next, film differential scanning calorimetry (DSC) of the obtained st-PMMA-C60 fullerene complex was performed. The result is shown in FIG. 5A shows the case of st-PMMA film prepared from toluene, and FIG. 5B shows the film of st-PMMA-C60 fullerene composite prepared from toluene (content of C60 fullerene 11). (C) in FIG. 5 is a film of st-PMMA-C60 fullerene complex (C60) prepared from a toluene / 1,2-dichlorobenzene (hereinafter abbreviated as DCB) mixed solvent. The measurement result of each DSC of the fullerene content (25.2 wt%) is shown. The film of the st-PMMA-C60 fullerene complex prepared from toluene showed an endothermic peak that was considered to be due to melting of the crystal structure of the complex at 224.9 ° C. (see FIG. 5B). This is probably because st-PMMA formed a helical structure by including C60 fullerene, so that the helical structure was not broken even when the solvent was removed, and the crystal structure was maintained. Further, in the case of the film of the st-PMMA-C60 fullerene complex prepared from the toluene / DCB mixed solvent, the glass transition point was hardly observed, and ΔH of the endothermic peak of crystal melting increased ((c) in FIG. 5). reference). It is thought that this is because the crystallinity of the composite increased as the content of C60 fullerene increased.
Furthermore, X-ray diffraction of the obtained film was measured. The results are shown in FIG. FIG. 6 (a) shows the case of st-PMMA film prepared from toluene, and FIG. 6 (b) shows the film of st-PMMA-C60 fullerene complex prepared from toluene (C60 fullerene content 11.7 wt. (C) of FIG. 6 shows the case of a film of st-PMMA-C60 fullerene composite (C60 fullerene content 25.2 wt%) prepared from a toluene / DCB mixed solvent. (D) shows the case of C60 fullerene alone precipitated from a toluene solution. As a result, in the film of the st-PMMA-C60 fullerene complex, reflection derived from the crystal structure was observed (see (b) and (c) of FIG. 6). The diffraction pattern of X-ray diffraction is different from that of the st-PMMA film (see FIG. 6A) or the C60 fullerene alone (FIG. 6D), and the st-PMMA-C60 fullerene complex. However, these were shown to be completely different.

Next, st-PMMA-C60 fullerene was spread on the water surface, a monomolecular film layer (LB film) was prepared, and observed with an atomic force microscope (AFM). The result is shown in FIG. 7 as a color photograph replacing the drawing. The left side of FIG. 7A shows a low magnification AFM image (height image, size: 2 μm × 2 μm) of the LB film (10 mN / m) of the st-PMMA-C60 fullerene complex, and the right side is a photograph on the left side. The profile of the height measured along the red line part of is shown. The left side of FIG. 7B shows a height image (size: 75 nm × 75 nm) of the same sample observed at a high magnification, and the right side shows the phase image. The upper right of FIG. 7 (B) schematically shows the result based on the phase image. From the atomic force microscope image, in addition to the C60 fullerene aggregate having a thickness of about 5 nm, a uniform crystal structure having a thickness of 1 nm or less could be observed (see FIG. 7A). Such a crystal structure is not observed in the st-PMMA simple substance and the C60 fullerene simple substance, and is considered to be a crystal structure of a monomolecular film of the st-PMMA-C60 fullerene complex, and the C60 fullerene is included in the crystal structure. Have been arranged.
Next, the molecular dynamics of the st-PMMA-C60 fullerene complex was calculated. The result is shown in the schematic diagram of FIG. (A) in FIG. 8 is an initial stage in which 10 C60 fullerenes are arranged at intervals of 9.2 angstroms inside the helix of the st-PMMA 180-mer rotated 10 times at a helical pitch of 9.2 angstroms (A) per revolution. A model of the structure is shown, and only the internal C60 fullerene is written on the right side. FIG. 8B shows a calculation result after 100 ps at a temperature of 10 K from the initial structure model, and FIG. 8C shows a calculation result after a further 1 ns at a temperature of 400 K. As a result, from the initial model, C60 fullerene was found in the st-PMMA helix by molecular dynamics calculation at a temperature of 10 ps at a temperature of 100 ps (see FIG. 8B) and at a temperature of 400 K at a time of 1 ns (FIG. 8c). The inclusion structure is retained, indicating that this structure is stable.

As described above, the present invention provides a fullerene-polymer composite capable of containing a fullerene stably and in a large amount dispersed.
The fullerene in the present invention may be any fullerene as long as it belongs to a category generally referred to as fullerene, and examples thereof include C60 fullerene, C70 fullerene, C74 fullerene, C76 fullerene, C78 fullerene, and C82 fullerene. These fullerenes may include chemical modification, surface treatment, gas or metal inside the fullerene. The fullerenes subjected to these treatments, fullerenes containing a metal or the like, and those using higher-order fullerenes are also included in the present invention. Fullerenes containing an inert gas such as helium and argon and metal atoms such as lithium and calcium are known as fullerenes having excellent optical properties and / or electrical properties. Such inert gases and metal atoms It is preferable to use fullerene encapsulating.
Examples of the polymer in the present invention include a synthesizable polymer that can incorporate fullerene into a helical structure. Preferable synthetic polymers include syndiotactic polymethacrylate polymers and syndiotactic polyacrylate polymers (both are hereinafter referred to as st-PMMAs). Examples of the ester in st-PMMAs include linear or branched alkyl groups having 1 to 30, preferably 1 to 20, 1 to 10, and further 1 to 5 carbon atoms. These alkyl groups may be substituted with a commonly used substituent such as an alkoxy group or halogen. Further, the stereoregularity of the polymer is preferably 60% or more in terms of syndiotactic triad content (rr content). Higher syndiotacticity is preferable because the polymer tends to have a helical structure and the content of fullerene to be incorporated increases. More preferably, the rr content is 80% or more, further preferably 90% or more, and most preferably 93% or more.
A copolymer may be used as long as the effects of the present invention are not impaired, and the structure may be a random, block, or graft copolymer. Two or more polymers may be blended and used.
In addition, the fullerene-containing polymer composite of the present invention has a melting point different from that of the fullerenes and polymers as raw materials, and their crystal structures are also different. Can be confirmed. For example, it can be confirmed by measuring the melting point with a differential scanning calorimeter (DSC), analyzing the crystal structure by X-ray diffraction, observing the crystal phase with a polarizing microscope, observing the crystal surface with an atomic force microscope (AFM), etc. .

The fullerene content of the fullerene-containing polymer composite of the present invention is not particularly limited as long as it is included in a helical structure. If it can be confirmed, it will be included in the fullerene-containing polymer composite of the present invention. The preferable content is 1% or more based on the total weight with the polymer, and in order to further secure the effect, the content is preferably 2% or more, more preferably 5% or more. On the other hand, the upper limit is preferably as many as possible, and no limitation is required.
Furthermore, from the AFM observation of the monomolecular film (LB film) of the fullerene-containing polymer complex of the present invention and the verification of the structural stability by molecular dynamics calculation, the fullerene-containing polymer complex of the present invention is a polymer It was shown that fullerenes are arranged one-dimensionally inside the helix. Therefore, the present invention also provides a fullerene-containing polymer composite in which fullerenes are arranged one-dimensionally along the helical axis of the polymer.

The method for producing the fullerene-containing polymer composite of the present invention includes a synthetic polymer compound having a helical structure, preferably a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer, and fullerene dissolved in a common solvent. And a method of removing the solvent after the treatment. More specifically, a synthetic polymer compound having a helical structure, preferably a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer is added to a solution in which fullerene is dissolved, and these are heated and dissolved. And a method of cooling it to near room temperature to gelate it and separating it from a solvent by centrifugation or the like. The order of mixing the polymer and fullerene is not limited. The fullerene may be solubilized later in the polymer solution, or the fullerene solution may be added. Furthermore, it is possible to obtain a fullerene-containing polymer composite by adding a fullerene solution after the polymer is heated and dissolved in a solvent, cooled to room temperature and gelled in advance.
The solvent in this method is not particularly limited as long as it is a solvent capable of dissolving fullerene and polymer, but preferred solvents include, for example, toluene, 1,2-dichlorobenzene, chlorobenzene, bromobenzene. , Benzene, butyl acetate, dimethylformamide and the like, or a mixture thereof.
The temperature at which these are heated is sufficient as long as they are dissolved. For example, the temperature is about 60 ° C. to 150 ° C., and an arbitrary temperature up to the boiling point of the solvent can be set. The amount of the solvent used may be an amount that becomes a gel or a solid by cooling after heating and dissolution, and can be used in a large amount, but it requires labor to remove the solvent as much as possible. A small amount is preferable.
Furthermore, as a means of increasing the inclusion amount of fullerene, a solvent having a high solubility of fullerene and a solvent having a high solubility of polymer are combined, dissolved in different solvents, and then mixed together, and then the solvent is removed. A method is also possible. For example, fullerene can be obtained by dissolving fullerene in dichlorobenzene having a high solubility of fullerene and a polymer in toluene having a high solubility of the polymer, and then mixing them together to obtain a fullerene polymer complex containing a high concentration of fullerene. In this case, the volume ratio of dichlorobenzene to toluene is preferably dichlorobenzene to toluene = 5/95 to 85/15, more preferably 10/90 to 55/45.
Since the fullerene-containing polymer complex of the present invention can be obtained as a crystalline complex, it can be separated from the solvent by centrifugation or filtration. Further, the solvent may be separated by distilling off the solvent, but in this case, unencapsulated fullerene may be mixed, and therefore, it is preferable to further purify as necessary.

The fullerene-containing polymer composite of the present invention can be formed into a film shape (film shape) or the like in the same manner as a normal polymer material. A monomolecular film (LB film) can also be used.
The fullerene-containing polymer composite of the present invention contains a functional fullerene, and can be applied as a polymer material capable of expressing functions such as optical properties and electrical properties of the fullerene. . For example, it can be used as industrial products such as photoelectric conversion elements, resist materials, and quantum dot elements.

  The fullerene-containing polymer composite of the present invention is a polymer material that can stably contain a large amount of dispersed fullerene in a one-dimensional arrangement, and can be molded into any shape as a polymer material. Since it is possible, it can be used as industrial products, such as a photoelectric conversion element, a resist material, and a quantum dot element. In addition, the fullerene-containing polymer composite of the present invention can be easily and inexpensively manufactured without a large-scale manufacturing facility, and various molecular devices using fullerene can be easily and inexpensively manufactured in large quantities easily. can do.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited at all by these Examples.

Production of Fullerene-Containing Polymer Complex Using Syndiotactic Polymethyl Methacrylate (hereinafter referred to as st-PMMA) and [60] Fullerene (hereinafter referred to as C60 Fullerene) as Raw Materials C60 Fullerene in Toluene Solution (1 mg / mL , See (a) of FIG. 1) To 1 mL of st-PMMA (number average molecular weight 460,000, syndiotactic triad content (rr content) 93.5%) 10 mg was added and heated to 110 ° C. to obtain a homogeneous solution It was.
When this solution is cooled as it is to room temperature, gelation occurs (see FIG. 1B). When this gel was sedimented by centrifugation (1700 g for 10 minutes (g is gravitational acceleration)), the supernatant liquid was colorless and transparent, and only the lower gel part was colored deep purple (see FIG. 1 (c)). ). This dark purple coloration indicates that st-PMMA and C60 fullerene form a complex. To confirm this, the relationship between the amount of added polymer and the amount of C60 fullerene incorporated is determined by UV-visible spectroscopy. It investigated using the photometer.
As the amount of polymer added increased, the concentration of C60 fullerene remaining in the supernatant decreased and the amount of C60 fullerene incorporated into the gel increased. It was found that about 1.3 mg of C60 fullerene was incorporated per 10 mg of st-PMMA at a polymer concentration of 10 mg / mL and a C60 fullerene concentration of 2 mg / mL (see FIG. 2). From this result, it was confirmed that fullerene was incorporated in the gel.
Furthermore, the present inventors confirmed from the results described below that C60 fullerene was not merely a contaminant, but formed a complex that was included in the inner pore of the st-PMMA helix.

St-PMMA-C60 fullerene complex gel thermal stability st-PMMA-C60 fullerene complex gel formed in deuterium-substituted toluene (st-PMMA concentration 10 mg / mL, C60 fullerene concentration 2 mg / mL) The thermal stability of was examined by 1H-NMR. Although the NMR signal of the polymer is observed in a high-temperature uniform solution state, the signal is not observed when gelation occurs due to a temperature drop (see FIG. 3A).
Therefore, when the signal intensity of the polymer was plotted against the temperature and the gelation temperature was estimated, the gelation temperature of the st-PMMA-C60 gel shifted to the higher temperature side by about 20 ° C. than when C60 fullerene was not added. (See FIG. 3B). This result shows that the gel incorporating C60 fullerene is more stable than the st-PMMA gel incorporating toluene alone, and that C60 fullerene does not exist as a simple interstitial material. Show.

Production of gel of st-PMMA-C60 fullerene complex using toluene and 1,2-dichlorobenzene as a solvent By using 1,2-dichlorobenzene (hereinafter referred to as DCB) as a solvent, the concentration of C60 fullerene was reduced. St-PMMA can be gelled under high conditions (DCB C60 fullerene solubility is about 10 times that of toluene). However, since the amount of C60 fullerene included by DCB alone decreased, a mixed solvent of toluene and DCB was examined. The results are shown in Table 1 below.

A mixed solution of C60 fullerene in toluene and DCB was prepared by appropriately mixing a C60 fullerene / toluene solution (2 mg / mL) and a C60 fullerene / DCB solution (20 mg / mL). 1 mL of a C60 fullerene mixed solution was added to 10 mg of st-PMMA (number average molecular weight 460,000, syndiotactic triad (rr content) 93.5%), and then heated to 110 ° C. to obtain a uniform solution. The mixture was gradually cooled to room temperature and gelled to prepare a st-PMMA-C60 fullerene complex gel using toluene and DCB as solvents. The obtained sample was separated into a gel part and a supernatant part by centrifugation (1700 g for 10 minutes), and the amount of C60 taken into the gel was calculated by measuring the ultraviolet-visible absorption spectrum of the supernatant part.
As a result, the amount of C60 fullerene incorporated by toluene alone is only 1.32 mg per 10 mg of polymer, but the C60 fullerene concentration can be increased by mixing the DCB solution of C60 fullerene, and the C60 fullerene incorporated accordingly. It was found that 3.37 mg of C60 fullerene was incorporated per 10 mg of polymer at toluene / DCB = 50/50 (v / v).

Production of st-PMMA-C60 Fullerene Composite Film A st-PMMA-C60 fullerene composite gel was prepared from a C60 fullerene toluene solution (concentration 2 mg / mL) at a polymer concentration of 10 mg / mL. An excessive amount of C60 fullerene was removed by washing the gel with toluene. The obtained gel was dried under reduced pressure at room temperature for 12 hours and further at 160 ° C. for 12 hours to remove the solvent, thereby producing a st-PMMA-C60 fullerene composite film having a C60 fullerene content of 11.7 wt%. Similarly, a film of st-PMMA-C60 fullerene complex having a C60 fullerene content of 25.2% by weight was produced using a toluene / DCB mixed solvent in which the amount of C60 fullerene included was increased.
When the obtained film was observed with an optical microscope, in the st-PMMA-C60 fullerene composite film, since the polymer and C60 fullerene formed a composite, the C60 fullerene content was as high as 25.2% by weight. Nevertheless, no phase separation was observed even when the solvent was removed (see FIG. 4C). When the film of the st-PMMA-C60 fullerene complex was observed with a polarizing microscope, birefringence was observed, indicating that the complex was crystallized (see FIG. 4D).
Next, differential scanning calorimetry (DSC) of the film was performed at a heating rate of 10 ° C./min in a nitrogen atmosphere. The film of st-PMMA-C60 fullerene complex (C60 fullerene content 11.7% by weight) prepared from toluene showed an endothermic peak at 224.9 ° C., which is probably due to melting of the crystal structure of the complex (FIG. 5). (See (b)). Since st-PMMA forms a helical structure by including C60 fullerene, it is considered that the helical structure was not broken even when the solvent was removed, and the crystal structure was maintained. Furthermore, in the film of st-PMMA-C60 fullerene complex (C60 fullerene content 25.2 wt%) prepared from a toluene / DCB mixed solvent, almost no glass transition point is observed, and ΔH of the endothermic peak of crystal melting increases. (See (c) of FIG. 5). It is thought that this is because the crystallinity of the composite increased as the C60 fullerene content increased.
Furthermore, when the X-ray diffraction of the obtained film was measured, reflection derived from the crystal structure was observed in the st-PMMA-C60 fullerene composite film (see FIGS. 6B and 6C). The obtained diffraction pattern is different from the known st-PMMA-solvent complex (see Non-Patent Document 4) and the C60 fullerene alone (see (d) of FIG. 6). It was shown that a complex was formed.

Comparative Example 1
A st-PMMA gel was prepared in toluene in the same manner as in Example 1 except that it did not contain C60 fullerene. This was dried under reduced pressure at room temperature for 12 hours and further at 160 ° C. for 12 hours to remove toluene, and a st-PMMA film containing no C60 fullerene was prepared. When the film prepared from the st-PMMA gel was observed with a polarizing microscope, it did not show birefringence (see FIG. 4B). Next, differential scanning calorimetry (DSC) of the film was performed in a nitrogen atmosphere at a heating rate of 10 ° C./min. The st-PMMA film showed only the glass transition point at 126.7 ° C. (see FIG. 5A). This is probably because st-PMMA cannot retain the helical structure by removing toluene, and the crystal structure does not remain. Moreover, when the X-ray diffraction of the obtained film was measured, the st-PMMA film showed only an amorphous halo (see FIG. 6A).

Comparative Example 2
It-PMMA-C60 fullerene film was prepared using isotactic PMMA (it-PMMA) which does not form a helical structure in toluene. 20 mg of it-PMMA (number average molecular weight 490,000, isotactic triplet (mm content) 97.5%) was dissolved in 0.5 mL of a C60 fullerene toluene solution (concentration 2 mg / mL) at room temperature. With it-PMMA, gelation did not occur and a solution was obtained. The solvent was removed under reduced pressure at room temperature to obtain a film of it-PMMA-C60 fullerene having a C60 fullerene content of 4.8% by weight.
When the obtained film was observed with an optical microscope, it-PMMA-C60 fullerene did not form a complex. Therefore, phase separation occurred even when the C60 fullerene content was 4.8% by weight, and precipitation of C60 fullerene was observed. (See (e) of FIG. 4).

  A st-PMMA-C60 fullerene complex was formed on the water surface. The st-PMMA-C60 fullerene complex could also be formed by a monomolecular film on the water surface. A dilute benzene mixed solution of st-PMMA and C60 fullerene complex (st-PMMA concentration 6.6 × 10 −3 mg / mL, C60 fullerene concentration 7.3 × 10 −4 mg / mL) is spread on the water surface and after compression on the mica substrate The monomolecular layer (LB film) was transferred and observed with an atomic force microscope. FIG. 7 shows an atomic force microscope image thereof. In addition to the C60 fullerene aggregate having a thickness of about 5 nm, a uniform crystal structure having a thickness of 1 nm or less could be observed. Such a crystal structure is not observed in the st-PMMA simple substance and the C60 simple substance, but is considered to be a crystal structure of the st-PMMA-C60 fullerene complex monomolecular film, and the C60 fullerene is included in the crystal structure. Arranged.

  The kinetic calculation of the st-PMMA-C60 fullerene complex was performed. The stability of the structure in which C60 fullerene was included in the st-PMMA helix was verified by molecular dynamics calculation. Based on the crystal structure reported for the st-PMMA-solvent complex, a helical structure of st-PMMA was created, and an initial model was constructed in which C60 fullerenes were arranged at 0.92 nm intervals ((( a)). From this initial model, molecular dynamics calculations were performed at a temperature of 10 K for a time of 100 ps (see FIG. 8B) and at a temperature of 400 K for a time of 1 ns (see FIG. 8C). The structure including C60 fullerene was retained, suggesting that this structure is stable.

  The fullerene-containing polymer composite of the present invention is a polymer material that can stably contain a large amount of fullerenes in a one-dimensional arrangement in a large amount. ) And the like, it can be used as an industrial product such as a photoelectric conversion element, a resist material, a quantum dot element, and has industrial applicability.

FIG. 1 is a drawing showing a state of a C60 fullerene toluene solution (a), a st-PMMA-C60 fullerene gel of the present invention prepared in toluene before centrifugation (b), and after centrifugation (c). This is a substitute photo. FIG. 2 is a graph plotting the amount of C60 fullerene incorporated against the added amount of st-PMMA. FIG. 3 is a 1H-NMR spectrum of a st-PMMA-C60 fullerene gel of the present invention prepared in (A) heavy toluene at 25 ° C. and 100 ° C. with a polymer concentration of 10 mg / mL and a C60 fullerene concentration of 2 mg / mL. is there. The signal indicated by * is a signal derived from a solvent. (B) It is the graph which plotted the ratio of the MMA unit which has gelatinized with respect to measurement temperature. The plot shown on the right side (red) is that of the gel of the st-PMMA-C60 fullerene of the present invention (◯: temperature drop measurement, ●: temperature rise measurement), and the plot shown in black is the st with no C60 fullerene added. -It is a thing of a PMMA gel ((circle): temperature fall measurement, (circle): temperature rise measurement). FIG. 4 shows st-PMMA films (a) and (b), st-PMMA-C60 fullerene composite film of the present invention (C60 fullerene content 25.2 wt%) (c) and (d), and it-PMMA. -Photomicrograph of C60 fullerene film (C60 content 4.8 wt%) (e). (A), (c) and (e) are taken under open nicols, and (b) and (d) are taken under crossed nicols. The scale bar is 200 μm. FIG. 5 shows (a) a st-PMMA film prepared from toluene, (b) a st-PMMA-C60 fullerene composite film of the present invention (C60 fullerene content 11.7% by weight) manufactured from toluene, and (c) The DSC measurement result of the st-PMMA-C60 fullerene composite film (C60 fullerene content 25.2 weight%) of this invention manufactured from the toluene / DCB mixed solvent. About 6 mg of the sample was put in an aluminum container and measured from room temperature to 300 ° C. in a nitrogen atmosphere at a heating rate of 10 ° C./min. Tg is the glass transition point, Tm is the melting point of the crystal, and ΔHm is the melting enthalpy at that melting point. FIG. 6 shows (a) a st-PMMA film prepared from toluene, (b) a st-PMMA-C60 fullerene composite film (C60 fullerene content 11.7% by weight) of the present invention manufactured from toluene, and (c) toluene. X-ray diffraction measurement results of the st-PMMA-C60 fullerene composite film of the present invention (C60 fullerene content 25.2 wt%) produced from a DC / DCB mixed solvent, and (d) C60 fullerene alone precipitated from a toluene solution Indicates. FIG. 7: (A) Low-magnification AFM image (height image, size: 2 μm × 2 μm) (left) and red line of LB film (10 mN / m) of the st-PMMA-C60 fullerene complex of the present invention The height profiles (right) and (B) measured in this manner are photographs instead of a drawing showing height images (size: 75 nm × 75 nm) (left) and phase images (right) of the same sample observed at high magnification. FIG. 8 schematically shows the results of molecular dynamics calculation of the st-PMMA-C60 complex. (A) An initial structural model in which ten C60 fullerenes are arranged at intervals of 9.2 angstroms inside a st-PMMA 180-mer spiral which is rotated 10 times at a helical pitch of 9.2 angstroms per revolution. Only writes internal C60 fullerenes. (B) Calculation result after 100 ps at a temperature of 10 K from the initial structure model. (C) Calculation results after 1 ns at a temperature of 400K. The calculation is performed with the number of atoms (3305 atoms) and volume being constant, and with a time step width of 0.5 fs.

Claims (10)

  A fullerene-containing polymer composite comprising a fullerene encapsulated in a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer.   The fullerene-containing polymer composite according to claim 1, wherein the fullerene is encapsulated in a helical structure of a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer.   The fullerene-containing polymer composite according to claim 1 or 2, wherein the syndiotactic polymethacrylate polymer is syndiotactic polymethyl methacrylate.   The fullerene-containing polymer composite according to any one of claims 1 to 3, wherein the fullerene-containing polymer composite has a melting point different from each simple substance and / or a crystal structure different from each simple substance. body.   The fullerene-containing polymer composite according to claim 1, wherein the fullerene content is 1% by weight or more.   The fullerene-containing polymer composite according to any one of claims 1 to 5, wherein the fullerene is a fullerene having 60 or more carbon atoms.   A method for producing a fullerene-containing polymer composite comprising dissolving a syndiotactic polymethacrylate polymer or a syndiotactic polyacrylate polymer and a fullerene in a common solvent and then removing the solvent.   The solvent is a good solvent for a syndiotactic polymethacrylate-based polymer or a syndiotactic polyacrylate-based polymer, and the solvent of the polymer gels with time or temperature change. The method described.   Fullerene, syndiotactic polymethacrylate-based polymer or syndiotactic polyacrylate-based polymer, and fullerene are dissolved in different solvents, mixed together, and then the solvent is removed. How to manufacture. The solvent or common solvent is at least one selected from the group consisting of toluene, 1,2-dichlorobenzene, chlorobenzene, bromobenzene, benzene, butyl acetate, and dimethylformamide, or a mixture thereof. The method of crab.