JPH10206309A - Quality evaluating method for liquid repellent film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quality evaluating method for a liquid repellent film to evaluate a characteristic of the liquid repellent film from a relationship map of a previously found film thickness and a contact angle and the film thickness and a dielectric constant by particularly forming a liquid crystal cell on the liquid repellent film, and measuring the contact angle or the dielectric constant by irradiation of the light in the method to evaluate liquid repellent capacity of a liquid repellent film processing part. SOLUTION: In a quality evaluating method of a liquid repellent film formed in a liquid repellent film processing part, a liquid crystal cell is formed on the liquid repellent film processing part, and a transparent base board 5 having a liquid crystal orientation film is arranged through a spacer 3 and a liquid crystal 4, and after the whole is packed (7) in a vacuum, and the light is applied, and the transmitted light or the reflected light is investigated, and a contact angle by water repellency is evaluated by the relationship between previously found orientation of the liquid crystal and a liquid repellent film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the liquid repellency of a liquid repellent component, and more particularly to a method for forming a liquid crystal cell on a liquid repellent film and irradiating light to measure a contact angle or a dielectric constant. Also, the present invention relates to a method for evaluating the quality of a liquid-repellent film, which evaluates the characteristics of the liquid-repellent film from a previously obtained relationship map of the film thickness and the antenna and the film thickness and the dielectric constant.

[0002]

2. Description of the Related Art In a fuel injection valve (hereinafter, referred to as an injector) of an internal combustion engine or the like, it is necessary to reliably shut off fuel or flow an appropriate flow rate by opening and closing the valve. In addition, foreign substances such as oil, additives, and moisture are present in the fuel, and the foreign substances, which accumulate during operation and are referred to as deposits, impede the flow of the fuel and the like. When deposits accumulate, even if the injector components are manufactured with high precision, it becomes a hindrance to fuel flow and becomes a problem in internal combustion engines. Recently, it has been considered to perform a process of forming a liquid-repellent film on various components for the purpose of reducing the adhesion of the deposit. However, this type of thin film is colorless and transparent in the visible light region and has a very small thickness, so that it is difficult to identify the film itself. If this film is not formed as expected, a desired effect cannot be expected, so it is important to confirm and evaluate that a liquid-repellent film has been formed.

Conventionally, the thickness of a thin film used for electronic parts and mechanical parts is about 100 nm to 0.1 mm. It cannot be used for measuring the thickness of a liquid-repellent film having a thickness of 100 nm or less. Therefore, the determination of the presence or absence of the liquid-repellent film has been performed by the static contact angle of the visual liquid, the magnitude of the insulation resistance value, Auger electron spectroscopy (hereinafter referred to as AES), or the like. In the nondestructive evaluation method described above, there are problems such as point measurement up to the millimeter, measurement of a thin film such as a liquid-repellent film is difficult, and reproducibility is poor. Table 1 shows the advantages and disadvantages of the conventional liquid repellent film evaluation method.

[0004]

[Table 1]

[0005] To summarize the above problems, the nondestructive evaluation method can only obtain information on the outermost surface.
Poor reproducibility, skill required for measurement, destruction evaluation method (material analysis) The sample is altered by the measurement. 1
It takes a long time to measure points. C. The equipment itself is very expensive, and the common factor between the two is that there are restrictions on the sample shape. On the other hand, as a method of evaluating the liquid repellency in the pores of a component having a pore inner wall subjected to a liquid repellent treatment from the chemical structure, in the conventional technique, the pore portion is cut in the length direction to cut the inner wall. Exposure to X-ray elemental analysis or AE
Analysis by S was performed. All of the above-mentioned conventional methods are based on the premise that the nozzle is split in half.Since splitting the nozzle in half requires skill and multi-step processing, it takes time and cost, and the inner wall of the nozzle half is Because of the concave surface, the method for measuring the contact angle of a water drop, which is generally used for evaluating liquid repellency, cannot be used, so that there is a problem that direct evaluation of liquid repellency is difficult. Therefore, a non-destructive evaluation method that does not need to divide the nozzle in half is required.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an FA
A method for evaluating the liquid repellency of a liquid repellent film using S (fluoroalkylsilane) has been studied, and the liquid contact angle measured by a liquid crystal cell upon irradiation with light can be evaluated from a map of the relationship with the orientation of the liquid crystal. It is an object of the present invention to provide a method for evaluating the quality of a liquid-repellent film.

Another object of the present invention is to examine a method for evaluating the liquid repellency of a liquid repellent film using FAS (fluoroalkylsilane), and to determine the complex permittivity measured by a liquid crystal cell upon irradiation with light. It is an object of the present invention to provide a method for evaluating the quality of a liquid-repellent film, which can be measured and evaluated from a map relating to the orientation of liquid crystal. Further, another object of the present invention is to form a liquid crystal cell by sucking the liquid crystal, irradiate light in the same manner as described above, and map the contact angle of the liquid measured by the liquid crystal cell with the orientation of the liquid crystal. It is an object of the present invention to provide a method for evaluating the quality of a liquid-repellent film that can be evaluated from the viewpoint of a liquid repellent film. Another object of the present invention is to suck the liquid crystal, form a liquid crystal cell, and provide a conductive plate on the liquid crystal cell,
It is another object of the present invention to provide a method for evaluating the quality of a liquid-repellent film, in which a complex dielectric constant measured by a liquid crystal cell is measured in the same manner as described above and can be evaluated from a map showing a relationship with the orientation of the liquid crystal.

[0008]

An object of the present invention is to provide a method for evaluating the quality of a liquid-repellent film formed on a liquid-repellent film-treated component, wherein a liquid crystal cell is formed on the liquid-repellent film-treated component. , A transparent substrate with a liquid crystal alignment film is arranged via a spacer and liquid crystal,
After the whole is vacuum-packed, light is irradiated to examine transmitted light or reflected light, and the contact angle due to water repellency is evaluated from the relationship between the orientation of the liquid crystal and the liquid repellent film determined in advance. This is achieved by a liquid film quality evaluation method.

Another object of the present invention is a method for evaluating the quality of a liquid-repellent film formed on a liquid-repellent film-treated component, wherein a liquid crystal cell is formed on the liquid-repellent film-treated component, and a spacer and a liquid crystal are formed. A liquid crystal alignment film-equipped conductive plate is provided through the device, and after vacuum-packing the whole, the complex permittivity between the liquid-repellent film-treated component and the conductive plate is checked, and the liquid crystal orientation and complex permittivity obtained in advance are determined. This is also achieved by a method for evaluating the quality of a liquid repellent film, which is characterized by evaluating the water repellency from the relationship of Further, the above object is a method for evaluating the quality of a liquid-repellent film formed on the inner wall of a pore of a nozzle-like component, in which the tip of the nozzle-like component is immersed in the liquid crystal, and the liquid crystal is injected into the pore by capillary action. Aspirate, detect the transmitted light of the light irradiated from one of the pores at the other of the pores, and evaluate the contact angle due to water repellency from the relationship between the orientation of the liquid crystal and the liquid-repellent film, which is obtained in advance. It is also achieved by the characteristic quality evaluation method of the liquid repellent film.

Another object of the present invention is to provide a method for evaluating the quality of a liquid-repellent film formed on the inner wall of a fine hole of a nozzle-like part,
By immersing the tip of the nozzle-like part in the liquid crystal and sucking the liquid crystal into the pores by capillary action, inserting a conductive member into this liquid crystal and measuring the complex dielectric constant between the nozzle-like part and the conductive member, It is also achieved by a method for evaluating the quality of a liquid-repellent film, which is characterized by evaluating the water-repellency from the relationship between the orientation of the liquid crystal and the complex permittivity, which is determined in advance.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the arrangement of liquid crystal molecules is changed by the interaction between a functional group on the surface of the film imparting liquid repellency and a terminal group of the liquid crystal molecules. In addition, the optical and electrical characteristics of liquid crystal molecules differ depending on the tilt of the molecular chains. Therefore, the magnitude of the liquid repellency can be evaluated by detecting the inclination of the liquid crystal molecules by electrical or optical means.

The present invention has been made in view of the above-described circumstances, and is capable of performing nondestructive, reproducible, quantitative measurement, high sensitivity, and high quality on the quality of a liquid repellent film using FAS.
An object of the present invention is to provide a method and a device capable of visualizing the liquid repellency of both points / surfaces, and evaluating the initial characteristics of liquid repellency and its durability in a short time. The feature of the invention that solves the above-mentioned problems is that, with respect to the liquid repellent film using FAS, the interaction between the functional group on the film surface that imparts the liquid repellency to the film and the terminal group of the liquid crystal molecule causes And that the liquid crystal molecules are arranged differently depending on the arrangement, density, etc. of the functional groups, and that the physical properties of the liquid crystal molecules are different in the direction parallel to the long axis of the molecule and in the direction perpendicular to the molecule (FIG. 13). An object of the present invention is to make it possible to evaluate the presence / absence of a liquid-repellent film and a functional group on the liquid-repellent film and the magnitude of the liquid-repellent ability by detecting the liquid-repellent film.

[0013]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. Example 1 This example is a method for evaluating the liquid repellency of a part of a liquid repellent film formed on a smooth flat plate using optical means. FIG. 1A shows a flat plate 2 made of a material having a high light transmittance or light reflectivity in which a liquid repellent film 1 is uniformly formed on a certain surface. The processing for evaluating the liquid repellency of the liquid repellent film is shown in FIGS. In this embodiment, the flat plate 2
A glass (fine glass for LCD) with an inorganic thin film formed on one side for smoothing; a spacer 3 having a polystyrene spherical particle diameter of 6 μm; and a liquid crystal 4 serving as a host liquid crystal commercially available multi-component nematic N-type liquid crystal. A commercially available dichroic dye was used.

First, as shown in FIG. 1A, spacers 3 for an LCD or the like are uniformly dispersed on a liquid-repellent film at a certain density. Further, a predetermined amount or more of liquid crystal 4 for an LCD or the like is dropped (FIG. 1B). Next, the base on which the liquid crystal alignment film 6 (a liquid repellent film having a known liquid repellency is possible) is formed on the flat plate 5 having a high light transmittance so that the alignment film forming site side is in contact with the liquid crystal dropping surface of the sample to be measured. (FIG. 1 (c)). Next, the substrate is put in a bag for the vacuum pack 7 and vacuum-packed while keeping the substrate from shifting. The degree of vacuum at this time may be such that liquid crystal between cells is not sucked out.

This vacuum pack is used to form a simple cell (prevent liquid crystal leakage) and to keep the cell gap constant (FIG. 1D). Next, the light source 8
The light detector 9 is installed as shown in FIG. 1E or FIG. 1F, and the light reflectance or light transmittance of the simple cell is measured. In this embodiment, as shown in FIG. 2A, the fact that the alignment (angle θ) ability of the liquid crystal molecules 10 differs depending on the size of the liquid repellency of the liquid repellent film is used. Therefore, the direction of the liquid crystal molecules at the site changes. Further, since the arrangement of the liquid crystal molecules near the periphery changes due to this influence, the light transmittance or the light reflectance also changes (FIG. 2B). For this reason, if the relationship between the arrangement of liquid crystal molecules and the light transmittance or light reflectance, and the correlation between the arrangement of liquid crystal molecules and the contact angle of a certain liquid, is understood,
From the light transmittance or the light reflectance, the contact angle with respect to the liquid at the site can be estimated (FIG. 2C). Further, if the simple cell is disassembled after the evaluation and the surface of the liquid repellent film to be evaluated is washed with a weak organic solvent or the like, the liquid repellency of the liquid repellent film is not affected and is not affected.

Embodiment 2 This embodiment is a method for evaluating the liquid repellency of the entire surface of a liquid repellent film formed on a smooth flat plate by using an electric means. FIG. 3A shows a flat plate 11 made of a conductor having a liquid repellent film 1 formed uniformly on a certain surface. FIGS. 3B to 3D show a process for evaluating the liquid repellency of the liquid repellent film.

First, as shown in FIG. 3A, spacers 3 for an LCD or the like are sprayed on the liquid repellent film to a certain extent. Further, a predetermined amount or more of the liquid crystal 4 for an LCD or the like is dropped (FIG. 3B). Next, on a flat plate 11 made of a conductor,
A liquid crystal alignment film 6 (a liquid repellent film having a known liquid repellency) may be formed on the substrate so that the alignment film forming site side is in contact with the liquid crystal dropping surface of the sample to be measured. (FIG. 3 (c)). Lastly, the substrate is put in a bag for the vacuum pack 7 while keeping the substrate from shifting, and vacuum-packed while leaving only a portion to be an electrode outside (FIG. 3D). The degree of vacuum at this time may be such that liquid crystal between cells is not sucked out.

The vacuum packing is performed to form a simple cell (to prevent leakage of liquid crystal) and to keep the cell gap constant. In the present embodiment, FIG.
As shown in (c) and (c), depending on the magnitude of the liquid repellency of the liquid repellent film,
The alignment ability of liquid crystal molecules is different. Accordingly, since the arrangement of the liquid crystal molecules at the site changes, the complex permittivity between the electrodes (simple cell) also changes as shown in FIGS. 4B and 4D.
Further, as shown in FIG. 6, the substrate 11, the liquid crystal 4, and the lyophobic film 1
The electrical equivalent circuit of a simple cell consisting of the following, the correlation between the arrangement of liquid crystal molecules and the complex permittivity, and the arrangement of liquid crystal molecules (FIG. 5)
If the correlation between (a)) and the contact angle of a certain liquid (FIG. 5 (b)) is grasped, it is possible to estimate the liquid contact angle of the relevant site from the value of the complex permittivity. Also in this case, if the simple cell is disassembled after the evaluation and the surface of the liquid repellent film to be evaluated is washed with a weak organic solvent or the like, the liquid repellency of the liquid repellent film is not affected and is not affected.

Embodiment 3 This embodiment is a method for evaluating the liquid repellency of the entire surface of a liquid repellent film formed on a smooth inner surface of a cylinder having a sufficiently small diameter by using an optical means. Cylinder 1 with liquid repellent film 1 formed uniformly on inner surface
2 is shown in FIG. FIGS. 7A to 7C show a process for evaluating the liquid repellency of the liquid repellent film. FIG. 7 (a)
The cylinder 12 is vertically immersed in the liquid crystal 4 as shown in FIG. next,
The liquid crystal 4 is sucked into the cylinder 12 by capillary action (FIG. 7).
(B)). Next, the cylinder 12 is slowly pulled up from the liquid crystal 4 (FIG. 7C). Then, a light source 8 and a photodetector 9 are installed before and after the cylinder, respectively. (FIG. 7 (e)) According to the same principle as in Example 1, the light transmissivity before and after the cylinder changes depending on the level of the liquid repellency of the liquid repellent film inside the cylinder. Can be estimated (FIG. 8). Also in the present embodiment, the liquid crystal sucked into the cylinder is blown off with compressed air or the like, and is washed again.
The measurement sample can be reused.

Embodiment 4 The present embodiment is a method for evaluating the liquid repellency of the entire surface of a liquid repellent film formed on a smooth inner surface of a cylinder having a sufficiently small diameter by using an electric means. FIG. 9D shows a cylinder 13 made of a conductor having the liquid-repellent film 1 formed uniformly on the inner surface. FIGS. 7A to 7C show a process for evaluating the liquid repellency of the liquid repellent film.
Shown in As shown in FIG. 7A, the cylinder 13 is vertically
Soak in Next, the liquid crystal 4 is sucked into the cylinder 13 by capillary action (FIG. 9B). Next, the cylinder 13 is slowly pulled up from the liquid crystal 4 (FIG. 9C). And the cylinder 13
A round bar 14 made of a conductor sufficiently smaller than the diameter of the inside of the cylinder 13 is inserted from one of the front and rear sides so as to correspond to the portion where the liquid-repellent film 1 is formed inside the cylinder. (FIG. 7
(E)) According to the same principle as in the second embodiment, in this embodiment, FIG.
As shown in (a) and (c), the alignment ability of liquid crystal molecules differs depending on the level of the liquid repellency of the liquid repellent film. Therefore, since the arrangement of the liquid crystal molecules at the site changes, the complex permittivity between the electrodes (simple cell) also changes as shown in FIGS. 10B and 10D. Further, as shown in FIG. 12, an electrical equivalent circuit of a simple cell including the substrate 11, the liquid crystal 4, and the liquid repellent film 1, the correlation between the arrangement of liquid crystal molecules and the complex permittivity, and the arrangement of liquid crystal molecules and the contact angle of a certain liquid. If the correlation (FIG. 11B) is grasped, it is possible to estimate the liquid contact angle of the relevant site from the value of the complex permittivity. That is, the complex dielectric constant between the cylinder and the round bar inserted inside the cylinder changes depending on the magnitude of the liquid repellency of the liquid-repellent film inside the cylinder, and the value of the liquid contact angle of the relevant portion is estimated from this. be able to. Also in this method, the measurement sample can be reused similarly to the third embodiment.

[0021]

According to the present invention, a transparent substrate constituting a liquid crystal cell is provided on a liquid-repellent film, and a relationship map is prepared in advance by irradiating light to determine a liquid crystal orientation and a change in photorefractive index or complex dielectric constant. It is possible to accurately and non-destructively evaluate the uniformity or the liquid repellency of the liquid repellent film by comparing the measurement result of the optical refractive index or the complex dielectric constant with this map.

[Brief description of the drawings]

FIG. 1 is a diagram of a process according to a first embodiment of the present invention, in which (a) a spacer is provided, (b) a liquid crystal is dropped, (c) a substrate, and (d).
It is a figure which shows a vacuum pack, (e) light irradiation (upper part), and (e) light irradiation (lower part).

FIGS. 2A and 2B are diagrams showing results according to Example 1 of the present invention, in which (a) liquid crystal molecules, (b) the relationship between the liquid crystal molecule orientation angle and light transmittance,
(C) is a diagram showing the relationship between the liquid crystal molecule alignment angle and the contact angle with water.

FIG. 3 is a diagram of a process according to a second embodiment of the present invention, in which (a) a spacer is provided, (b) a liquid crystal is dropped, (c) a substrate, and (d).
It is a figure showing a vacuum pack.

FIGS. 4A and 4B are graphs showing results according to Example 2 of the present invention, in which (a) the relationship between liquid crystal molecules, (b) the relationship with the complex permittivity due to the liquid crystal molecule alignment, (c) the liquid crystal molecules, and (d) the relationship between the liquid crystal molecule alignment. It is a figure which shows the relationship with a complex dielectric constant.

FIGS. 5A and 5B are graphs showing results according to Example 2 of the present invention, wherein FIG. 5A is a graph showing the relationship between liquid crystal molecules and FIG.

FIG. 6 is a diagram illustrating an electrical equivalent circuit according to a second embodiment of the present invention.

FIG. 7 is a diagram of a process according to a third embodiment of the present invention, in which (a) a liquid-repellent film is provided, (b) immersion in liquid crystal, (c) pull-up,
FIG. 5D is a diagram illustrating a state of forming a liquid repellent film, and FIG.

FIG. 8 is a diagram showing results according to Example 3 of the present invention, in which (a) liquid crystal molecules, (b) the relationship between the liquid crystal molecule orientation angle and light transmittance,
(C) is a diagram illustrating a relationship between a liquid crystal molecule alignment angle and a contact angle with respect to a liquid.

FIG. 9 is a diagram of a process according to a fourth embodiment of the present invention, in which (a) a liquid-repellent film is provided, (b) immersion in liquid crystal, and (c) pull-up.
FIG. 3D is a diagram illustrating a state of forming a liquid-repellent film, and FIG.

FIG. 10 is a diagram showing results according to Example 4 of the present invention, wherein (a)
It is a figure which shows the relationship between a liquid crystal molecule and (b) complex dielectric constant by liquid crystal molecule orientation, and (c) liquid crystal molecule and (d) complex dielectric constant by liquid crystal molecule orientation.

FIG. 11 is a diagram showing results according to Example 4 of the present invention, in which (a)
It is a figure which shows the relationship between a liquid crystal molecule and the liquid contact angle by (b) liquid crystal molecule orientation.

FIG. 12 is a diagram illustrating an electrical equivalent circuit according to a fourth embodiment of the present invention.

FIG. 13 is a diagram showing physical and electrical characteristics of a conventional liquid crystal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid-repellent film 2 ... Flat plate with high light transmittance or light reflectance 3 ... Spacer 4 ... Liquid crystal 5 ... Flat plate with high light transmittance 6 ... Liquid crystal alignment film 7 ... Vacuum pack 8 ... Light source 9 ... Photodetector 10 ... Liquid crystal molecule 11: Conductor flat plate 12: Cylinder 13: Conductor cylinder 14: Conductor round bar 15: Conductor (cylinder + round bar) 16: Parallel direction to molecular long axis 17: Direction perpendicular to molecule long axis n: light refractive index (transmittance, reflectance) ε: dielectric constant

Claims (4)

[Claims] 1. A method for evaluating the quality of a liquid-repellent film formed on a liquid-repellent film-treated component, comprising: forming a liquid crystal cell on the liquid-repellent film-treated component; A transparent substrate with a film is provided, and the whole is vacuum-packed and then irradiated with light to examine transmitted light or reflected light, and a contact angle due to water repellency is obtained from a relationship between liquid crystal orientation and a liquid repellent film determined in advance. A liquid repellent film quality evaluation method characterized by evaluating the following. 2. A method for evaluating the quality of a liquid-repellent film formed on a liquid-repellent film-treated component, comprising: forming a liquid crystal cell on the liquid-repellent film-treated component; After installing a conductive plate with a film and vacuum-packing the whole, examine the complex permittivity between the liquid-repellent film-treated component and the conductive plate, and determine the water repellency based on the relationship between the orientation of the liquid crystal and the complex permittivity determined in advance. A liquid repellent film quality evaluation method characterized by evaluating the following. 3. A method for evaluating the quality of a liquid-repellent film formed on an inner wall of a pore of a nozzle-like part, wherein the tip of the nozzle-like part is immersed in liquid crystal, and the liquid crystal is sucked into the pore by capillary action. The feature is that the transmitted light of the light irradiated from one of the pores is detected by the other of the pores, and the contact angle due to water repellency is evaluated from the relationship between the orientation of the liquid crystal and the liquid repellent film, which is obtained in advance. Quality evaluation method of liquid repellent film. 4. A method for evaluating the quality of a liquid-repellent film formed on the inner wall of a pore of a nozzle-like part, wherein the tip of the nozzle-like part is immersed in liquid crystal, and the liquid crystal is sucked into the pore by capillary action. By inserting a conductive member into the liquid crystal and measuring the complex permittivity between the nozzle-shaped component and the conductive member, the water repellency is evaluated from the relationship between the orientation of the liquid crystal and the complex permittivity, which is obtained in advance. A method for evaluating the quality of a liquid-repellent film, comprising: