JPH0678394B2 - Method for producing polyacetylene - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to electrical materials. More specifically, the present invention relates to an organic substance having a polyacetylene bond that exhibits conductivity and a nonlinear optical effect.

2. Description of the Related Art Polymers of acetylene derivatives have a one-dimensional main chain having a pi-electron conjugated system in the molecule, and therefore have conductivity and nonlinear optical effects, and are widely studied as optical and electronic functional materials. ing.

As a method for producing polyacetylene, the polymerization method of Shirakawa et al. Using a Ziegler-Natta catalyst is well known.

On the other hand, if an amphipathic acetylene derivative having a hydrophobic group and a hydrophilic group is used, a monomolecular film can be formed on the water surface, and a cumulative film can be formed by the Langmuir-Blodgett (LB) method. Is well known.

The LB method is a promising method as a construction means in recent years in developing a molecular device in which a molecule itself has a function. According to the LB method, a monomolecular film of an acetylene derivative of the order of several tens of angstroms can be prepared, and a cumulative film thereof can be easily obtained.

Problems to be Solved by the Invention However, currently known polyacetylene derivatives are
In an atmosphere containing oxygen, it is unstable with respect to heat, pressure, ultraviolet rays, and the like, so studies for stabilizing it are underway.

However, a method for stabilizing an acetylene derivative polymer has not been found yet.

Means for Solving Problems In the present invention, a fatty acid-based substance containing an acetylene group (independent unsaturated triple bond that is not conjugated) dissolved in an organic solvent is spread on a water surface to evaporate the organic solvent. After that, the molecules of the substance containing the acetylene group remaining on the water surface are scraped together on the water surface in the direction of the water surface with a barrier, and a predetermined molecular pressure is applied to the monomolecular film on the water surface, that is, Langmuir (L) film. Polymerization using radiation such as rays, electron beams or gamma rays, or after accumulating LB film of acetylene derivative on a given substrate under a certain surface pressure group, polymerizing using radiation as described above. It was discovered that stable polyacetylene was formed even in an atmosphere containing oxygen.

That is, it was found that by radiation-polymerizing the molecule of the acetylene derivative while compressing it under a constant surface pressure group, linear polyacetylene having a continuous conjugated system and an ultrahigh molecular weight (superconjugated polymer) can be produced.

Further, it was found that polyacetylene having a longer conjugated system can be produced by applying a direct-current bias in the surface direction when the L film is radiation-polymerized or when the LB film is accumulated.

Action That is, X-rays, electron beams or gamma rays are applied while applying a certain surface pressure to the LB film of the acetylene derivative accumulated on the predetermined substrate or the L film of the acetylene derivative spread on the water surface under a certain constant surface pressure. By performing radiation polymerization using, for example, a linear ultra-high molecular weight polyacetylene having a continuous conjugated system can be produced by compensating for the reduction in molecular area during polymerization. That is, by constantly compressing the acetylene derivative molecules arranged in a monomolecular state at a constant pressure, it is possible to maintain the condition that the radiation polymerization reaction of the acetylene derivative monomer continuously continues, and the gap generated by the molecular contraction at the time of polymerization. Can be filled to form a linear ultrahigh molecular weight polyacetylene having a continuous conjugated system.

Further, when the acetylene derivative molecule is scraped in the plane direction on the water surface with a barrier, or when a direct current bias is applied in the plane direction during radiation polymerization, the orientation of the monomer molecule is further improved, and the conjugated system is longer. It is possible to make polyacetylene.

Hereinafter, the details of the present invention will be described using examples.

Example There are many samples used, but omega tricosinoic acid (ω-tricocynoi), which is one of the acetylene derivatives, is used.
c Acid (TCA); CH≡C- (CH ₂ ) ₂₀ -COOH) will be described.

The radiation polymerization of the L film and the accumulation of the LB film were carried out in a class 100 clean room of yellow light illumination in which light of 500 nm or less was cut using a trough IV (Joice-Loebl Trough IV) manufactured by JOYS LABEL. At this time, the room temperature in the clean room is adjusted to 23 ± 1 ° C and the humidity is adjusted to 40 ± 5%. The LB film was accumulated in 25 layers, but all were Y-type. The substrate used for accumulating the LB film is a Si substrate on which an oxide film having a diameter of 3 inches is formed. The radiation sources used in the radiation polymerization reaction are X-rays and electron beams. In addition, FTIR spectrum was measured to confirm the polymerization of the L film and the LB film on the water surface.

First, in order to confirm the difference in molecular density or molecular orientation, the surface pressure molecule occupancy area characteristic (π-A curve) of the TCA · L membrane was measured by changing the salt concentration and pH of the aqueous phase. FIG. 1 shows π-A curves under two typical water tank conditions.

Next, TCA ・ L accumulated at typical points A and B in Fig. 1
The reactivity of the B film to X-ray was examined. The TCA / LB films accumulated at points A and B were irradiated with X-rays, respectively, and the residual film rate (gamma characteristic) after immersion in ethanol solvent showed the change as shown in Fig. 2, and both were 100-200 mJ / The solvent became insoluble at cm ² . FTIR spectra were measured for further chemical analysis. 3 and 4 show changes in the FTIR spectrum of the TCA / LB film accumulated at points A and B, respectively, due to X-ray irradiation. As shown in the third and fourth figures, both reduced the absorption of 3300 cm ^-1 (absorption of ≡CH) with the X-ray irradiation, the absorption of new 1650 cm ^-1 (absorption of C = C) It can be seen that polyacetylene having (-CH = CH-) n bonds was produced due to the increase in the number and the insolubility of the TCA / LB film in the solvent. That is, it became clear that the reaction shown in FIG. 5 (b), that is, polyacetylene was produced from the molecular arrangement shown in FIG. 5 (a).

Furthermore, Fig. 6 shows the TCA accumulated at points A and B in Fig. 1.
-The change in infrared absorption intensity at 3300 cm ^-1 (absorption of CH) due to X-ray irradiation of the LB film is shown. Absorption at 3300 cm ^-1 decreased with X-ray irradiation in both the A and B points, but the TCA / LB film accumulated at the B point had higher reactivity. Therefore, it was revealed that the molecular orientation and the molecular density of TCA molecules at the time of accumulation are important when producing polyacetylene using the TCA / LB film.

On the other hand, it was also confirmed that when the TCA.L film under the conditions of points A and B in FIG. 1 was directly irradiated with X-rays at about 100 to 200 mJ / cm ² , the polymerization also proceeded and became insoluble in the ethanol solvent.

From the above results, it was confirmed that in the X-ray polymerization method, the TCA.L film and the LCA.LB film produced polyacetylene through the radiation polymerization process as shown in FIG.

On the other hand, when the TCA / L film or TCA / LB film is irradiated with an electron beam having high energy (gamma ray has the same effect),
Similarly, it was confirmed that the TCA / LB film became solvent insoluble.

Incidentally, the polyacetylene produced in this manner is conventionally produced by the catalytic method, and compared with the polyacetylene derivative,
It was remarkably stable against heat, pressure, ultraviolet rays, etc. even in an atmosphere containing oxygen.

In addition, when the diacetylene derivative molecules are scraped in the plane direction on the water surface with a barrier, or when radiation polymerization is performed, a direct current bias of several tens of volts is applied in the plane direction to further improve the orientation of the monomer molecules. It was confirmed that it is also possible to make polyacetylene having a long conjugated system.

In the above examples, only the TCA.LB film and the TCA.L film are shown. However, if the LB film can be formed by including an acetylene (C≡C) group in the molecule, the accumulation conditions are different. It will be clear that a similar method can be used. Further, it goes without saying that the chemical adsorption method can be used instead of the LB film formation method by adding a water-active group such as --SiCl ₃ instead of the terminal carboxylic acid. .

EFFECTS OF THE INVENTION By using the method of the present invention, it is possible to highly efficiently produce a stable polyacetylene polymer having excellent conductivity and nonlinear optical effect. In addition, according to this method, it is theoretically possible to produce a linear ultrahigh molecular weight polyacetylene having a conjugated system having a length of several mm or several cm or more. It is extremely effective in manufacturing the device used. In addition, by optimizing the type and manufacturing conditions of the diacetylene derivative monomer, which will be the raw material in the future, the conjugated system will have a linear and ultra-high molecular weight with a length of several tens of centimeters or several meters or more. Since it seems that stable polyacetylene can be produced, this method enables the production of an organic superconducting material that does not require cooling.

[Brief description of drawings]

Fig. 1 shows the π-A curve of TCA ・ L film under two typical water tank conditions, and Fig. 2 shows TCA ・ L accompanying X-ray irradiation.
Gamma characteristics of B film, 3 and 4 are X of TCA / LB film
Fig. 5 shows the change in FTIR spectrum due to radiation irradiation.
Conceptual diagram of radiation polymerization process of A ・ LB film, Fig. 6 is 3300cm ^-1
FIG. 6 is a diagram showing a change in infrared absorption intensity of the TCA / LB film in Example 1 due to X-ray irradiation.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01B 1/12 C 7244-5G

Claims (8)

[Claims] 1. An acetylene (C≡ dissolved in an organic solvent).
C) After developing a substance containing a group on the water surface and evaporating the organic solvent, molecules of the substance containing the acetylene group remaining on the water surface are scraped on the water surface in the water surface direction with a barrier, and a predetermined surface is formed. X-rays while applying pressure to the molecules of the substance,
A method for producing polyacetylene, which comprises irradiating with radiation such as electron beam or gamma ray to polymerize. 2. The method for producing polyacetylene according to claim 1, wherein the polymerization is performed by irradiating light while applying a predetermined surface pressure and at the same time applying a DC electric field in a direction parallel to the water surface. . 3. The method for producing polyacetylene according to claim 1 or 2, wherein the water contains an inorganic salt. 4. The method for producing polyacetylene according to claim 1, wherein the substance containing an acetylene group is tricosinoic acid. 5. A substance containing an acetylene group dissolved in an organic solvent is spread on the surface of water to evaporate the organic solvent, and then the molecules of the substance containing the acetylene group remaining on the surface of the water are directed to the surface of the water. And a predetermined surface pressure is added to the molecules of the substance while accumulating on a predetermined substrate, and the thin film containing acetylene groups accumulated on the substrate is irradiated with radiation such as X-rays, electron beams or gamma rays. A method for producing polyacetylene, which comprises irradiating and polymerizing. 6. A method of accumulating while applying a predetermined surface pressure and applying a DC electric field in a direction parallel to the water surface at the same time in the step of accumulating on a predetermined substrate while applying a predetermined surface pressure. 6. The method for producing polyacetylene according to claim 5. 7. The method for producing polyacetylene according to claim 5 or 6, wherein the water contains an inorganic salt. 8. The method for producing polyacetylene according to claim 5, wherein the substance containing an acetylene group is tricosinoic acid.