JPH0412242A - Observing method for surface of high polymer - Google Patents

Abstract

PURPOSE:To observe the image of a crystal structure of a high polymer as a natural stereoscopic image by black-and-white-inverting a transmission electron microscope image of a one-step replica film formed by eliminating an amorphous part of the high polymer by etching, shadowing it by a metal and vapor- depositing carbon. CONSTITUTION:The surface of a high polymer being a sample 10 is subjected to etching and its amorphous part is eliminated selectively. Subsequently, a shadowing metal 17 is vapor-deposited to the surface of the sample 10, and shadowing is executed. Also, a film of carbon is vapor-deposited to the whole surface thereon, and the metal 17 and the carbon film are peeled off. In such a way, a one-step replica film is obtained. Next, the obtained replica film is photographed by a transmission electron microscope. Thereafter, the obtained microscope image is subjected to black-and-white inversion so that in the end, the part to which the metal 17 is vapor-deposited more is displayed more whitely, that is, so that the part of sunshine and the part of shade become white and black, respectively so as to match a person's visual sense. Accordingly, the observation m line with a person's visual sense can be executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for observing the surface of a high-molecular polymer, and more specifically, the present invention relates to a method for observing the surface of a high-molecular polymer. Concerning observation methods that allow us to understand the three-dimensional effect and true form.

[Prior art] Conventionally, as a method for observing the surface of a polymer, a replica film is created by etching the surface of a polymer as a sample, and this is observed using a transmission electron microscope (TEM). There are known ways to do this.

For example, etching methods for preparing samples for observation include rR, H, 0LLBY, A, M, HODG.
E.

and D, C, BASSETT, Journal
of Polymer 5science:PolylTl
er Physics Edjtion, Vol. 17
, 627-843 (1979) J, rD, R, N0RT
ON and A, KELLER, POLYMER, V
ol, 2B704-716 (1985) J.

In addition, as a method for preparing replicas from plant samples,
There is a technique disclosed in Japanese Patent Application Laid-Open No. 54-54566.

FIG. 1 is a cross-sectional view showing the state of shadowing in the -stage replica method. In the figure, it is assumed that the surface of the sample 10 has already been etched. Shadowing occurs when the angle θ from the surface of the sample 10 is 30 to 4.
This is carried out by scattering metal from the direction of arrow S, which is about 0°, and depositing it on the sample 10. When the convex portion 11 is present in the sample 10, there are formed portions where the vapor-deposited metal is deposited and portions where the vapor-deposited metal is not. Vapor-deposited metal 17 is deposited at position 12, side wall position f&13 of convex portion 11, and upper position 14 of convex portion 11 on the near side as viewed from the direction of arrow S. On the other hand, the vapor-deposited metal 17 is not vapor-deposited at the shadowed position]6. A vapor-deposited metal 17 is vapor-deposited at a position 15 beyond the shadow.

After shadowing, carbon is deposited on the entire surface of the sample 10. Then, by a known method, this carbon film and the vapor-deposited metal 1
7 and is peeled off from sample 10. Observe the peeled replica using a transmission electron microscope.

[Problems to be Solved by the Invention] By the way, when shadowing is performed as shown in FIG. 1 and a replica thereof is photographed using a transmission electron microscope, the photographic film is exposed as follows. That is,
At a position where more metal 17 is present, scattering and absorption of the electron beam is large, so the amount of exposure is small and the photographic film (so-called "negative") becomes whiter. On the contrary, metal 17
At a position where there is less electron beam scattering and absorption, the amount of exposure is large and the negative becomes darker.

For actual observation, this negative film is printed onto photographic paper. Therefore, in the photographic paper used for observation, the positions where more metal 17 is present are black, and the positions where less metal 17 is present are white.

However, the visual perception of images printed on photographic paper in this way is quite different from that seen by humans on a daily basis. In other words, from the perspective of human visual perception, when light hits from the direction of arrow S as shown in Figure 1, positions 12 to 15 corresponding to the sun are white (bright <), and position 16 corresponding to the shadow is black. (darker), but with the above photographic paper, the black and white are reversed.

Normally, those skilled in the art were forced to decipher this photographic paper photograph outside of everyday visual perception.

In view of the above-mentioned problems in the conventional example, the present invention has been developed to enable observation of the surface of a high-molecular polymer using a transmission electron microscope using a one-stage replica method in accordance with human daily visual perception. The purpose of the present invention is to provide a method for observing the surface of a high-molecular polymer.

[Means for Solving the Problems] In order to achieve the above object, the method for observing the surface of a polymer according to the present invention involves etching the surface of a polymer as a sample and selecting an amorphous portion. a replica film creation step in which a replica film is obtained by depositing shadowing metal and carbon on the surface of the sample and peeled off; and an imaging step in which a transmission electron microscope image of the replica film is obtained. The present invention is characterized by comprising an inversion step of inverting the transmission electron microscope image in black and white so that a portion where a larger amount of shadowing metal is deposited is displayed whiter.

[Function] According to the above configuration, the surface of the high molecular weight sample is first etched to selectively remove the amorphous portion. Next, a metal for shadowing is deposited on the surface of the sample to perform shadowing. Furthermore, a carbon film is deposited on the entire surface, and these shadowing metal and carbon films are peeled off using a well-known method. As a result, a −stage replica film is obtained. The single-stage replica film thus obtained is photographed using a transmission electron microscope. The microscopic image obtained by photography is inverted in black and white by an inversion process, and the area where more shadowing metal has been deposited appears whiter. The shaded areas are made to be white and the shaded areas are made to be black. This allows observation to be made in line with human visual perception.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

The example described here is an example in which a sample made of high-density polyethylene is prepared and its surface is observed.

(Etching process) First, a method of etching a sample made of high-density polyethylene will be explained. Etching is performed for the purpose of removing the amorphous portion of the sample and leaving the crystalline portion. By observing the crystalline portion while leaving it intact, it is possible to observe the plate-like crystal structure (i.e., the thickness, coordination, dislocation, tilt, and true shape of the surface) of the crystal.

First, in order to prepare a sample to be observed, high-density polyethylene in the form of a pellet is placed on a slide glass and heated to about 180°C on a hot stage to melt it. Press this, thickness 0.3~0.5 +n+n, diameter 1~1
．． Take a 5 cm disc-shaped sample.

Next, 1 wt % of potassium permanganate was added to a solution of concentrated sulfuric acid and concentrated phosphoric acid mixed at a ratio of 2:1, and the mixture was stirred in an ultrasonic cleaner for 1 hour. This stirring is performed to prevent potassium permanganate from turning into manganese dioxide, since the oxidizing power of the above solution is very strong. The above-mentioned disk-shaped sample is put into this, and stirring is continued for an additional 30 minutes to perform etching of the sample.

After etching, the sample is washed. For cleaning, use dilute sulfuric acid prepared at a water/soil/concentrated sulfuric acid ratio of 7:2, 25% hydrogen peroxide, water, and acetone at a temperature of 7:2.

Thereafter, it is vacuum dried to obtain an etching surface material.

(Replica membrane creation process) Next, a one-stage replica of the sample is created.

The step replica creation procedure is as follows.

First, place the sample on the slide/balance with the etched side facing up. Attach this to the vacuum evaporation equipment.

In this vacuum evaporation device, a tungsten filament, which is a platinum-palladium wire wound around 1 cm, is attached to a heater made by bending a tungsten wire.

The tungsten filament is attached so that the direction of the tungsten filament is upward at an angle of about 30 to 40 degrees with respect to the etched surface (observation surface) of the sample. Furthermore, two carbon rods with shaved tips are prepared, and the tips of these rods are placed close to each other directly above the sample.

Also, prepare a power source for energizing the tungsten filament and carbon fiber.

A vacuum pump is used to exhaust the air inside the vacuum evaporation apparatus in which the sample and the like are placed. Evacuation is carried out for 30 minutes, and the inside of the vacuum evaporation apparatus is made into a vacuum state. Thereafter, electricity is applied to the tungsten filament to make it incandescent and evaporate the platinum-palladium wound around it. The evaporated platinum palladium was applied to the etched surface of the sample.
The light is incident on the etched surface from a direction forming an angle of about 40 degrees, and is deposited on the sample surface as indicated by number 17 in FIG. From the above, shadowing was carried out.

Next, electricity is applied to the carbon rod placed directly above the sample. As a result, carbon evaporated from the carbon rod is scattered from directly above the sample, forming a carbon film over the entire surface of the sample. The energization of the carbon rod is repeated 3 to 4 times until the carbon film has a sufficient thickness.

Next, the sample is taken out from the vacuum deposition apparatus. Then, paste-like polyacrylic acid was dropped onto the sample carbon film and dried in a desiccator for 3 days. After drying, this polyacrylic acid is peeled off from the sample together with the platinum palladium and carbon film deposited by shadowing. Float the peeled product in distilled water with the polyacrylic acid side facing down, and
Leave for 3 hours.

In 2-3 hours, the polyacrylic acid dissolves in the distilled water, leaving a replica film. This is a grid for electron microscope (200
Scoop it up using a mesh scoop and use it as a sample for observation.

Next, photographing of this sample using a transmission electron microscope and black and white reversal will be explained.

(Imaging process) The sample placed on the above-mentioned electron microscope grid is photographed using a transmission electron microscope. The photographed negative film is then developed. In the conventional method, this negative film was printed onto photographic paper and used for visual observation.

(Reversal Step) In this embodiment, using an enlarger, this negative film is overlapped with an unphotographed film and exposed to produce a positive film. This positive film is then printed onto photographic paper to obtain a black and white reversal image.

FIG. 2 is an external view showing how a positive film is produced from a negative film. In the figure, 21 is an enlarger, 22 is a light source of the enlarger 2], and 23 is a frosted glass. Reference numeral 24 indicates an enlarging lens of the enlarging machine 21, but when producing a positive film from a negative film, the lens 24 is removed because it is a so-called solid printing process. 26 is a negative film taken with a transmission electron microscope,
27 indicates an unshot film. 25 is an arrow indicating scattered light scattered by the frosted glass 23 and traveling in the direction of the films 26 and 27.

As shown in the figure, the light emitted from the light source 22 of the enlarger 21 is scattered by the frosted glass 23. The scattered light 25 is
An unphotographed film 27 on which a negative film 26 is superimposed is irradiated. As a result, a positive film having an image obtained by inverting the black and white image of the negative film 26 can be obtained.

By printing this positive film onto photographic paper, it is possible to obtain a photograph that represents a black and white inverted image of the conventionally obtained image. In this photo, the areas where more platinum/palladium, which is a metal for shadowing, has been deposited appear whiter.

That is, positions 12 to 15 in FIG. 1 are shown in white, and position 16 is shown in black.

Figures 3 (a) and (b) both show transmission electron images showing the crystal structure (near the center of a crystal that has grown into a spherical shape) of a sample made of high-density polyethylene, which was photographed by etching a replica of the sample. This is a microscopic photograph. Figure 3 (a
) is a photograph obtained by the conventional method, and Figure 3(b) is a photograph obtained by the conventional method.
) is a photo after black and white inversion. The direct magnification at which the replica membrane was photographed was 15,000 times. The transfer from the negative film to the photographic paper in FIG. 3(a) has been enlarged twice. FIG. 3(b) shows a positive film obtained by inverting the negative film obtained in FIG. 3(a) to an undeveloped film at the same magnification and enlarging it to twice the size on photographic paper.

FIGS. 4(a) and 4(b) are also transmission electron micrographs showing the crystal structure of high-density polyethylene (near the periphery of spherically grown crystals).

FIG. 4(a) is a photograph obtained by the conventional method, and FIG. 4(b) is a photograph obtained by inverting the black and white of FIG. 4(a). The direct magnification at which the replica membrane was photographed was 30,000 times. Figure 4 (
The transfer from negative film to photographic paper in a) is a double enlargement. Figure 4(b) is similar to Figure 4(a).
) The positive film obtained by reversing the negative film obtained in 1.

As can be seen from these photographs, Fig. 3 (
In the photographs of Figures 3(b) and 4(b), it is difficult to see the irregularities on the surface, whereas in the photographs of Figures 3(b) and 4(b), the irregularities of the crystal structure can be seen from the top of the photograph. It shows a natural three-dimensional image formed when light hits it. Therefore, it is possible to observe a three-dimensional image that matches the natural visual perception of everyday human beings. In addition to giving a natural three-dimensional effect, there are also finer structures, such as those shown in Figure 4 (a, ).
It is also possible to accurately grasp minute features such as the spiral part slightly above the left center part and the inclination angle of the flat part near the middle. Figure 3(a) and Figure 4(a) by conventional method
In the photo, it is difficult to see these minute structures (for example, the angle of inclination of the flat part, etc.).

In addition, from the above-mentioned negative film 26 to unphotographed film 27
In the black-and-white reversal transfer of the image to , the unphotographed film 27 was a photographic film for a transmission electron microscope similar to a negative film. High-sensitivity films are not suitable for use in solid prints, but this photographic film for transmission electron microscopes has low sensitivity and can be suitably used for making solid prints from the negative film 26. Furthermore, the enlarging machine 21 for solid printing shown in FIG. 2 can also be used as an enlarging machine used when printing a film onto photographic paper. Therefore, the black and white reversal process can be performed without introducing any new equipment.

[Modifications of Embodiments] In the above embodiments, black-and-white reversal is performed by creating a positive film from a negative film, but any method that can perform black-and-white reversal may be used.

For example, the photographed film may be treated with chemicals to directly create the above-mentioned black and white inverted positive film. The procedure is similar to the method used to process film taken by an 8nun camera, for example the following (1).
~(V).

Therefore, as shown in Table 1 below, the exposure time was increased and the second developer was also changed. As a result, a positive film with black and white inversion was obtained, which could be printed onto photographic paper. The image on the photographic paper had a lot of unevenness due to chemicals, but it was clear.

Table 1 (i) The photographed film is first developed.

(if) bleaching the first developed film;

(iii) Expose the bleached film.

(jv) Second development of the exposed film.

(V) The second developed film is fixed to obtain a positive film.

It should be noted that photographic film for transmission electron microscopes has low sensitivity, such as 35IIlIn, which is used for ordinary visible light.
It does not reverse under film chemical processing conditions.

(*1)...p-(methylamino)phenol sulfate (commonly known as metol), sodium sulfite, hydroquinone,
A mixture of soda carbonate and potassium bromine.

Copinal is the brand name of a developer manufactured by Fuji Photo Film Co., Ltd.

Furthermore, it is also possible to take a photograph of the replica by a conventional method, which is not inverted in black and white, and then perform the above-mentioned chemical reversal operation on the photographic film and print it on photographic paper.

Alternatively, an image analysis method may be used. In particular, we directly captured an image of the created replica using a transmission electron microscope using a video camera, and electrically reversed the black and white intensity.
It may also be displayed on RT. If you do this,
A 3D image that matches the natural visual perception of humans can be displayed and observed in real time, which is very convenient.

In the above embodiment, so-called permanganate etching is performed using a solution of concentrated sulfuric acid and concentrated phosphoric acid to which potassium permanganate has been added, but the etching method is not limited to this. Any method that can remove the amorphous portion of the sample may be used.

For example, liquid phase etching using another solution, or gas phase etching such as plasma etching, sputter etching, or ion beam etching may be used. However, permanganic acid etching has the advantage of being able to clarify structural differences because it leaves less stain on the sample surface and has good selectivity between amorphous and crystalline materials.

Moreover, although the above-mentioned example showed an example in which a sample made of high-density polyethylene was observed, the method of the present invention is not limited to this, and various high molecular weight polymers can be used as a sample.

The polymeric substance targeted by the present invention is preferably a crystalline or semi-crystalline thermoplastic resin. Examples include polyolefin resins, polyamide resins, polyester resins, and the like.

[Effects of the Invention] As explained above, according to the method for observing the surface of a polymer according to the present invention, the amorphous portion of the polymer is removed by etching, and carbon is deposited by shadowing with metal. The transmission electron microscope image of the single-stage replica film created using the same method is reversed in black and white, so the image of the crystal structure of the polymer can be observed as a natural three-dimensional image that matches the natural visual sense of humans. It is also possible to accurately grasp minute structures such as crystal inclination and true surface morphology.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the state of shutter τ1·, 1° in the -stage replica method, Fig. 2 is an external view showing how a positive film is created from a negative film, and Fig. 3 (a ) is a transmission electron micrograph showing the crystal structure of the sample obtained by the conventional method; FIG. 3(b) is a transmission electron micrograph showing the crystal structure of the sample obtained by the method of the above example; Figure (a) is
Transmission electron micrograph showing the crystal structure of the sample obtained by the conventional method. FIG. 4(b) is a transmission electron micrograph showing the crystal structure of the sample obtained by the method of the above example. 0... Sample, 1... Convex portion, 7... Vapor deposited metal, 1... Enlarger, 6... Negative film, 27... Unphotographed film. Patent applicant Japan Petrochemical Co., Ltd.

Claims (1)

[Claims] (1) Etching the surface of the high molecular weight sample,
an etching step for selectively removing amorphous portions; a replica film creation step for obtaining a replica film by depositing shadowing metal and carbon on the surface of the sample and peeling it off; and transmission electron microscopy of the replica film. It is characterized by comprising an imaging step of obtaining an image, and an inversion step of inverting the transmission electron microscope image in black and white so that a portion where a larger amount of shadowing metal is deposited is displayed whiter. A method for observing the surface of high molecular weight polymers.