JPS6236095A - Formation of organic thin film crystal - Google Patents

Abstract

PURPOSE:To obtain the titled org. thin film crystal on a polymeric film by providing a temp. gradient in one direction in the plane of the polymeric film and growing a crystal with the org. crystal dispersed in the film as the seed crystal. CONSTITUTION:A soln. of a thin film-formable high polymer (A) such as PS and an org. substance (B) such as 2-hydroxy-4-methoxybenzylidene-4'- bromoaniline in 1,4-dioxane is spin-coated, for example, on an about 0.15mm- thick glass sheet 2 and dried to obtain a PS film 3 wherein the crystallites of the component (B) are dispersed. The glass sheet 2 coated with the film 3 is placed in an m.p. block 1 and inclined by a plastic spacer 7 so that the one side of the sheet 2 is brought into direct-contact with the block 1, then 2-hydroxy-4-methoxybenzylindene-4'-butylaniline 4 (C) is placed thereon, the block 1 is heated and kept at 50 deg.C, a glass sheet 5 is placed thereon, the laminate is cooled to 32 deg.C at the rate of 0.5 deg.C/min and the thin film single crystal 4 of the component (C) is grown between the film 3 and the glass sheet 5.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing organic thin film crystals.

(Prior art) There are three methods for producing organic crystals: crystal growth from a gas phase, crystal growth from a solution, and crystal growth from a molten state.
seeds are used.

(For these three types of crystal growth methods, see Maruzen Publishing, New Experimental Chemistry Course, Volume 1, Basic Operations [, PP, 639-750
, is well regarded. ) (Problems to be Solved by the Invention) However, the creation of organic thin film crystals has hardly been studied to date, and reports thereof are limited to crystals of polymer compounds. (For example, Izumi's comprehensive report (Journal of the Japanese Society for Crystal Growth, Vol. 11, PP 117-134.1984
(2010) describes examples of polyethylene thin film crystals and polyacetylene thin film crystals. ) Currently, there is no suitable method for producing organic thin film single crystals other than polymer compounds.

An object of the present invention is to provide a method for producing a thin organic film single crystal on a polymer film.

(Means for Solving the Problems) According to the present invention, in a method for producing an organic thin film crystal, in which an organic substance dispersed in a polymer film is used as a seed crystal and an organic substance is crystallized in a thin film form on the film, A method for producing an organic thin film crystal is obtained, which is characterized by creating a temperature gradient in a certain direction within the plane of a polymer film and growing the crystal in this direction.

The polymer membrane material used in the present invention may be any material as long as it has the ability to form a thin film. - Examples include polystyrene, polyvinyl chloride, etc. The compound serving as the seed crystal used in the present invention may be any compound as long as it can be dispersed as a crystal in the polymer film and can cause crystal growth of the target compound. The temperature gradient in the in-plane direction of the polymer film containing the seed crystal of the present invention may be created by any method, but the gradient must be obtained only in a certain in-plane direction.

- Examples include methods in which only one side of the substrate is brought into contact with a heat source, and methods in which the substrate is placed in a liquid or gas with a temperature gradient. The magnitude of the temperature gradient and its absolute temperature are determined by the combination of the seed crystal and the compound to be grown, but care must be taken because if the temperature gradient is too small, the seed crystal will be present throughout the film, resulting in polycrystallization. Must be set. When creating a temperature gradient in a certain direction within the plane of such a polymer membrane, there is no problem even if the gradient is created in a direction perpendicular to the plane.

(Function) Generally, when growing a single crystal from a seed crystal, the seed crystal is
It must be individual. If there are multiple seed crystals, growth will begin from each one and will not form a single crystal.

However, in the present invention, although there are a plurality of seed crystals, growth occurs only from the seed crystal that reaches the growth start temperature earliest because there is a temperature gradient. Once the growth is successful, crystallization progresses according to the temperature gradient.
In addition, a single crystal can be obtained because the grown crystal grows faster (homoebiaxial growth) than the growth from a seed crystal (heterobikix growth).

(Example) FIG. 1 is a schematic diagram showing an embodiment of the present invention.

18+a*X18m glass plate 2. (Thickness approx. 0.15m
), polystyrene (0,50f) with a molecular weight of 600,000 and 2-hydroxy-4-methoxybenzylidene-41
- Bromoaniline (hereinafter abbreviated as MS4BrA) (0,
1,4-dioxane (13,OF) dissolved in 1,4-dioxane (13,OF)
) The solution was spin coated at 500° rpm. 1 at 80℃
After drying for a while, a polystyrene film 3 in which MS4BrA microcrystals were dispersed in the film was obtained on the glass plate 2.

Melting point block 1 was used as a heat source in the following crystal growth experiment. A plastic spacer 7 is placed so that only one side of the glass plate coated with the film 3 is in direct contact with the melting point block.
2-Hydroxy-4-methoxybenzylidene-41-butylaniline 4 of Qmt.
(hereinafter abbreviated as M84BuA), melting point block l
was heated to 50°C to make it into a liquid crystal state. While maintaining the temperature at 50°C, an uncoated glass plate 5 was placed thereon and cooled to 32°C at a rate of approximately 0.5°C per minute. 3
When it was allowed to stand at 2° C. for 10 minutes, a thin film single crystal 4 of M84BuA was obtained between the film 3 and the glass plate 5 placed thereon. According to microscopic observation, crystal growth starts from the side opposite the side that is in contact with the melting point block 1 and progresses toward the side that is in contact with the melting point block 1, giving rise to multiple elongated single crystals. Recognize.

The crystal-to-liquid crystal transition temperature of the organic thin film crystal grown on the film 3 is 36.5° C., and this thin film turns red when irradiated with 365 nm ultraviolet light. Furthermore, in addition to the method in which one side of the glass plate 2 was brought into contact with each other, a single crystal could also be created by conducting a similar experiment by bringing one corner of the glass plate 2 into contact with each other.

Further, on the membrane 3, 2-hydroxy-4-methoxybenzylidene-41-hebutylaniline, 2-hydroxy-
Thin film crystals of salicylidene anilines such as 4-methoxybenzylidene-41-octylaniline were also created in a similar manner. The glass plate 5 placed on top during crystal growth was not necessarily necessary, and thin film crystals could be created without the glass plate 5. However, in order to obtain a uniform film thickness, it is desirable to have some kind of cover, although it is not limited to a glass plate.

As a reference example, when the above-mentioned thin film crystal was created by placing a glass plate coated with a polymer film in close contact with a melting point block, crystal growth occurred from multiple points and the entire film did not become a single crystal. . Therefore, it is clear that the temperature gradient of the present invention is effective for crystallizing the entire material into a single crystal.

(Effects of the Invention) The present invention provides a method for creating an organic thin film single crystal on a polymer film. Originally, on the male side, the seed crystals dispersed in the polymer film and the compound that grows into the thin film crystal are different, but they may be the same compound. Further, the polymer membrane material is not limited to polystyrene, and the coating method is not limited to spin coating, but may also be a casting method, an interfacial film forming method, or the like. Furthermore, it does not necessarily have to be fixed on the glass plate.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention. In the figure, 1 is a heat source whose temperature can be controlled, 2 is a glass plate, 3 is a polymer film in which seed crystals are dispersed, 4 is a layer to be crystallized (for example, liquid crystal), 5 is a cover with a glass plate, and 6 is an overall cover. ,7
represent plastic spacers, respectively 0 Agent F+'J'i! -I: Inner f2', j g Fig. 1: Melting point block 2 Glass plate 3: Polymer film with seed crystals dispersed 4: Layer to be crystallized 5: Cover (glass plate) 6: Overall cover 7: Plastic made spacer

Claims (1)

[Claims] In a method for producing organic thin film crystals, in which organic substances are crystallized into a thin film on the film using organic crystals dispersed in a polymer film as seed crystals, a temperature gradient is created in a certain direction within the plane of the polymer film, and 1. A method for producing an organic thin film crystal, characterized by growing the crystal.