JP2010156551A - Method for evaluating wettability of member, and method for manufacturing hydrophilic-water-repellent member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably evaluate the wettability of a member, and manufacture a hydrophilic or water-repellent member at the high quality, based on the evaluation of the wettability of the member of high reliability. <P>SOLUTION: A liquid W contacts a surface to be tested, by immersing a member to be tested 100 in the liquid, regardless of the wettability of the member to be tested. When an inclination angle of the member to be tested 100 is increased from 0° to 3°, 6°, 9°, 12° and 15°, images of air bubbles 102 attached to the member to be tested, having the bad wettability are indicated in a column B; and the images of the air bubbles 102 attached to the member to be tested having proper wettability are indicated in a column G. Even if the inclination angle of a stage 18a is increased to 15°, the air bubbles 102 attached to the member to be tested having poor wettability is attached to the member to be tested 100. When the inclination angle of the stage 18a is increased to 12°, the air bubbles 102 attached to the member to be tested having proper wettability, despite the attachment of the air bubbles 102 to the member to be tested 100 is transferred on the surface to be tested of the member to be tested, and is moved out of an imaging range as shown in a simulated arrow in the figure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for evaluating wettability of a member and a method for producing a hydrophilic / water-repellent member.

Conventionally, when it is necessary to evaluate the wettability of the surface of a member used in a liquid or in a high humidity atmosphere, the droplet method, the falling method, the expansion / contraction method, the Wilhelmy method, etc. have been used as the evaluation method. (For example, refer to Patent Documents 1 and 2).
JP 2007-42446 A JP 2006-19252 A

However, it is pointed out that the reliability of the data of the droplet method is significantly reduced in the case of a highly hydrophilic test member whose contact angle between the test surface and the droplet is less than 30 °, for example. ing. The reason is that since the surface tension of the test surface and the droplet exceeds the surface tension of the droplet itself, the droplet is unlikely to become a spherical surface with hysteresis by being strongly influenced by the test surface. It is because. In addition, in such a case, since the droplet shape is not in an equilibrium state, the droplet shape changes sequentially, and the meaning of visually acquiring the droplet shape is lost. This problem becomes more conspicuous when the material of the droplet is absorbed.
In addition, the falling method can acquire reliable data when the test surface has water repellency, but is still unsuitable when the test surface has hydrophilicity. In recent years, evaluation methods based on the advancing and receding angles of droplets have also been attempted, but in the case of a material whose hydrophilicity is ensured by the unevenness of the test surface, the liquid droplets are taken into the test surface while incorporating the liquid into the unevenness. , The droplet size changes and cannot be evaluated correctly. This problem also applies to the expansion / contraction method.

The Wilhelmy method is a method for evaluating the wettability of the surface of the member by placing the sample member in the liquid and measuring the surface tension of the material. There is a problem that the shape of the sample member is restricted, such as the need for processing.
The present invention has been made in view of the above problems, and an object thereof is to perform highly reliable wettability evaluation of a member. Another object of the present invention is to produce a high-quality hydrophilic or water-repellent member that is backed by wettability evaluation of a highly reliable member.

In order to solve the above problems, the member wettability evaluation method according to the present invention is based on the actual use conditions of the member in order to evaluate the wettability of the member surface used in a liquid or high-humidity atmosphere. This evaluates the wettability of the specimen under the inspection environment.
Further, the method for producing a hydrophilic or water-repellent member according to the present invention includes an affirmation for evaluating the wettability of the test member subjected to the surface modification treatment by the wettability evaluation method for the test member. A member having desired hydrophilicity or water repellency is produced.
(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) A method for evaluating the wettability of a member, wherein the test member is immersed in a liquid, and bubbles are attached to the test surface from below in a state where the test surface is held horizontally facing downward, An evaluation method in which the test member is tilted to measure the angle of rise and fall of the bubbles, and the wettability of the test member is evaluated based on the angle of rise and rise (Claim 1).
The method for evaluating the wettability of the member described in this section is to immerse the test member in the liquid when evaluating the wettability of the surface of the member used in the liquid or in a high humidity atmosphere. The liquid is brought into contact with the test surface regardless of the wettability. At this time, in the case where the wettability of the test member is poor, when bubbles are attached to the test surface in the liquid from below, the test surface is repelled in the same way as the liquid adhering to the test surface is repelled in the air. The surface tension between the test surface and the bubbles is superior to the surface tension between the liquid and the liquid, and the bubbles adhere to the test surface in such a manner that they directly contact the test surface.
On the other hand, when the wettability of the test member is good, when bubbles are attached to the test surface in the liquid from below, the liquid surface easily spreads in the air in the same way as the test surface. The surface tension between the test surface and the liquid is superior to the surface tension with the bubbles, and regardless of whether the test surface has irregularities or the surface roughness, the bubbles pass through the liquid layer (the test surface and Adheres to the test surface.

Here, in the case of a test member having good wettability and unevenness formed on the test surface, when a droplet is attached to the test surface in the air (conventional droplet method), the liquid is previously applied to the test surface. In such a case, the liquid adhering to the unevenness of the test surface and the liquid droplet adsorb each other, and the contact angle of the liquid droplet decreases. However, when the test surface is dry, there is no adsorption between the existing liquid and the liquid droplets, and sometimes there is high contact with the liquid droplets dropped on the sample surface, as in the case of poor wettability. Horns may appear. The method for evaluating the wettability of a member described in this section describes the error in determining the wettability of a member due to the variation in the contact angle caused by the presence or absence of the existing liquid on the test surface. This is avoided by measuring the angle of bubble elevation in the liquid.
In the present description, the “bubble rising angle” means that the test surface of the test member immersed in the liquid is held horizontally with the test surface facing downward, and the bubbles attached to the test surface from below are As a result of increasing the inclination angle of the test surface, it means the inclination angle of the test surface when it floats along the inclined test surface.

(2) The evaluation method according to (1) above, wherein the ambient temperature is within the range of the liquid phase temperature of the liquid (claim 2).
The method for evaluating the wettability of the member described in this section enables the determination of wettability based on the angle of bubble elevation in the liquid by setting the atmospheric temperature within the range of the liquid phase temperature of the liquid. As described above, an error in determining the wettability of the member due to the variation in the contact angle due to the presence or absence of the existing liquid on the test surface is avoided.

(3) In the above items (1) and (2), the volume of the bubble is measured to an amount determined according to the area of the test surface of the test member, and attached to the test surface. The evaluation method according to 1 or 2 (Claim 3).
In the member wettability evaluation method described in this section, the volume of bubbles is measured to an amount that can be determined according to the area of the test surface of the test member, and attached to the test surface. That is, if the bubbles are too large relative to the area of the test surface, the bubble cannot move up along the inclined test surface, but the sample member can be attached by attaching the measured bubbles to the test surface. Regardless of the area of the test surface, the movement of the bubbles on the test surface is caused, and the bubble ascending angle is measured.

(4) A method for evaluating the wettability of a member, wherein droplets or bubbles are arranged on a test surface of a test member, and at this time, the ambient temperature is set within the range of the liquid phase temperature of the droplet, or the atmosphere An evaluation method for evaluating the wettability of a test member on the basis of a drop angle of the droplet or an angle of rise of the bubble with a humidity in a range of 0% to 100% relative humidity (Claim 4).
The method for evaluating the wettability of a member described in this section is a method for evaluating the wettability of the surface of a member used in a liquid or a high-humidity atmosphere. By placing the test member in an atmospheric humidity of 0% or more and 100% or less, the test environment that matches the actual use conditions of the member is reproduced on the test surface.

Then, a droplet is dropped on the test surface, the wettability of the test member is evaluated based on the drop angle of the droplet, and the entire test surface becomes wet under the set atmospheric environment. In this case, air bubbles are arranged on the test surface, and the wettability of the test member is evaluated based on the bubble ascending angle.
In this description, the “dropping angle of the droplet” means that the droplet placed on the test surface is the result of an increase in the tilt angle of the test surface while the test surface of the test member is held horizontally. This means the inclination angle of the test surface when falling along the inclined test surface.

(5) In the above item (4), the evaluation method for appropriately changing the type and pressure of the atmospheric gas or the discharge pressure of the liquid droplets on the test surface when the liquid droplets or bubbles are arranged on the test surface (Claim 5).
The method for evaluating the wettability of a member described in this section should appropriately change the type and pressure of the atmospheric gas or the discharge pressure of the liquid droplets on the test surface when the liquid droplets or bubbles are arranged on the test surface. Thus, the inspection environment in accordance with the actual use conditions of the member is reproduced on the test surface.
By the way, when placing a droplet on the test surface, if the wettability of the test member is poor, it is well known that the contact angle of the droplet increases by repelling the liquid adhering to the test surface. However, even when the wettability of the test member is good, the contact angle of the droplet may increase. That is, in the case of a test member with good wettability and unevenness on the test surface, when a droplet is attached to the test surface in the air, the liquid is pre-adhered to the test surface. In this case, the liquid adhering to the unevenness of the test surface and the droplet adsorb each other, the droplet spreads on the test surface, and the contact angle decreases. On the other hand, when the test surface is in a dry state, adsorption of the existing liquid and droplets does not occur, so sometimes the liquid film spreading is inhibited by the air pockets on the test surface, resulting in poor wettability. As in the case, a high contact angle may appear in the droplet dropped on the test surface. The member wettability evaluation method described in this section changes the discharge pressure of droplets on the test surface by changing the contact angle due to the presence or absence of air accumulation on the test surface. Is appropriately increased to the extent that the droplets themselves do not blow off, so that the air pockets on the surface of the test surface are repelled, the shape and size of the droplets are maintained, and the falling angle is measured.

(6) In the above items (4) and (5), the volume of the droplet or the bubble is measured to an amount determined according to the area of the test surface of the test member, and the test surface is measured. Evaluation method to place. (Claim 6).
The member wettability evaluation method described in this section measures the volume of droplets or bubbles to an amount that can be determined according to the area of the test surface of the test member, and attaches it to the test surface. is there. That is, if the droplet or bubble is too large relative to the area of the test surface, the droplet or bubble cannot drop or float along the inclined test surface, but the measured droplet or bubble cannot be Regardless of whether the area of the test surface of the test member is wide or small, by attaching it to the test surface, it causes the movement of the droplet or bubble on the test surface, and measures the falling angle or the rising angle of the droplet or bubble. Is.

(7) In order to obtain the wettability required for the member, the surface of the member is modified, and the surface modification treatment is performed by the method for evaluating the wettability of the test member described in (1) to (6) above. A method for producing a hydrophilic or water-repellent member, comprising the step of evaluating the wettability of a test member that has been performed, and further modifying the surface of the member as appropriate according to the evaluation. The production method of (1) to (6) above evaluates the wettability of the test member subjected to the surface modification treatment by the wettability evaluation method of the test member described in the above items (1) to (6). Or the member which has water repellency is manufactured efficiently.

(8) The method according to (1) to (6), wherein the liquid is an organic solvent such as water or ethanol, and the bubbles are an inert gas such as air, oxygen, nitrogen, or argon.
The method for evaluating the wettability of a member described in this section, particularly when the member to be evaluated for wettability is a cell constituent member of a fuel cell, provides an inspection environment in accordance with the actual use conditions of the member. To reproduce.

(9) A wettability evaluation apparatus for a member, a water tank for immersing the test member in a liquid, a holding means for holding the test surface of the test member horizontally downward, and the test member An evaluation apparatus comprising a part or all of a bubble supply means for attaching bubbles to the test surface from below, a drive means for inclining the test member, and a measurement means for measuring a bubble elevation angle.
(10) In the above item (9), an evaluation apparatus comprising an atmospheric temperature control means for controlling the atmospheric temperature within the range of the liquid phase temperature of the liquid.
(11) In the above items (9) and (10), the volume of the bubble is measured to an amount determined according to the area of the test surface of the test member, and is attached to the surface of the test part An evaluation apparatus comprising means.
(12) In the above items (9) to (11), the measuring means is photographed by photographing means for photographing bubbles in which bubbles are attached to the test surface of the test member from below, and the photographing means. An evaluation apparatus that includes a part or all of a recording unit that records an image and an evaluation unit that obtains a rolling angle based on the image and evaluates the wettability of a test member.
According to the evaluation apparatus according to the items (9) to (12) above, the evaluation method according to any one of the items (1) to (3) is performed, and the effects described in the respective items are exhibited.

(13) An apparatus for evaluating the wettability of a member, wherein an atmospheric temperature control means for setting the atmospheric temperature within the range of the liquid phase temperature of water, and an atmospheric humidity control for setting the atmospheric humidity in the range of 0% to 100% relative humidity A part or all of the means, the droplet or bubble supply means for arranging the droplet or the bubble on the test surface of the test member, and the measurement means for measuring the drop angle of the droplet or the bubble rise angle Evaluation device including
(14) In the above (13), a gas supply means for changing the type of the atmospheric gas, a pressure control means for controlling the pressure of the atmospheric gas, when the droplets or bubbles are arranged on the test surface, An evaluation apparatus including a part or all of the pressure control means for controlling the discharge pressure of the droplet with respect to the test surface.
(15) In the above items (13) and (14), the volume of the droplet or the bubble is measured to an amount determined according to the area of the test surface of the test member, and the test surface is measured. An evaluation device comprising a weighing means to be arranged.
(16) In the above items (13) to (15), the measuring means is photographed by a photographing means for photographing a droplet or a bubble arranged on a test surface of the test member, and the photographing means. An evaluation apparatus including a part or all of a recording means for recording an image and an evaluation means for obtaining a roll-up angle or roll-up angle based on the image and evaluating the wettability of a test member.
According to the evaluation apparatus according to the items (13) to (16), the evaluation method according to any one of the items (4) to (6) is performed, and the effects described in the respective items are exhibited.

  Since this invention was comprised in this way, it becomes possible to perform the wettability evaluation of a highly reliable member. In addition, it is possible to manufacture a high quality hydrophilic or water repellent member backed by the wettability evaluation of a highly reliable member.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
First, a member wettability evaluation method according to a first embodiment of the present invention will be described with reference to FIGS. In the member wettability evaluation method according to the first embodiment of the present invention, as shown in FIG. 1, the test member 100 is immersed in water W, and the test surface is held horizontally with the test surface facing downward. In this state, the bubble 102 is attached to the test surface from below, the test member 100 is tilted, the rising angle θ of the bubble 102 is measured, and the wettability of the test member is evaluated based on the rising angle θ. It is.
At this time, the ambient temperature is set within the range of the liquid phase temperature of the liquid W. Therefore, when water is used for the liquid W, the temperature of the water is set to 0 ° C. or more and 100 ° C. or less, and the angle of rise θ is measured. In addition, the volume of the bubble 102 is measured to an amount determined according to the area of the test surface of the test member 100 and attached to the test surface. Specifically, in accordance with the area of the test surface of the test member 100, a bubble having a capacity capable of causing the operation of the bubble 102 on the test surface (the operation of lifting the bubble 102 along the test surface where the bubble 102 is inclined) is provided. By adhering to the test surface, the amount is measured so that the bubble 102 maintains a stable shape and size in the liquid during the operation.

  3 and 4 show an inspection apparatus 10 for carrying out the member wettability evaluation method according to the first embodiment of the present invention. The inspection apparatus 10 includes a water tank 12 for immersing the test member 100 in water, a holding means 14 for horizontally holding the test surface of the test member 100 downward, and a test surface of the test member 100. The bubble supplying means 16 for attaching the bubbles 102 from below, the driving means 18 for inclining the test member 100 together with the water tank 12, the measuring means 20 for measuring the angle of rise of the bubbles 102, and the ambient temperature of the liquid phase temperature of water. Atmospheric temperature control means 22 for controlling within the range is provided.

  The water tank 12 is a transparent rectangular container so that the inside can be visually recognized. The holding means 14 may be anything as long as it can stably hold the test member 100 in water, but in the example shown, a chaise long table is used. Further, the bubble supply means 16 shown in the figure has an injection needle-like air supply pipe 16a that is bent from the lower part to the upper part and is supplied to the test surface of the test member 100 attached to the lower surface of the holding means 14. I have. The air supply pipe of the bubble supply means 16 is provided with an arbitrary measuring means for accurately measuring the supplied air. In the illustrated example, the driving means 18 includes a stage 18a on which the water tank 12 is placed, and a triaxial actuator 18b that controls the inclination angle of the stage 18a.

The measuring means 20 for measuring the angle of elevation of the bubble 102 is an imaging means for photographing the bubble 102 attached to the test surface of the test member 100 (in the example shown, a camera 20a and a light 20b, which are integrated with the stage 18a). And a recording means (in the illustrated example, an information processing means such as a personal computer 20c) for recording an image photographed by the photographing means, and the angle of elevation is obtained based on the image. Evaluating means for evaluating the wettability of the test member (information processing means such as the personal computer 20c in the illustrated example) is provided. The measuring means 20 also includes angle measuring means such as an encoder for measuring the angle of the triaxial actuator 18b. The wettability evaluation may be automatically performed by image processing, or may be arbitrarily determined by an operator confirming the image.
In the illustrated example, the ambient temperature control means 22 includes a compressed air pipe 22a, a flow controller 22b, a humidifier (divergence type humidifier) 22c, a dry gas supply device 22d, an environmental tank 22e, and a back pressure adjustment valve 22f. Here, the environmental tank 22e is a container that can cover at least the water tank 12 placed on the stage 18a (in this case, a transparent container in consideration of photographing of bubbles in the liquid).
Note that the liquid W is not limited to water, and an organic solvent such as ethanol can be used as appropriate, and the bubbles 102 can use not only air but also an inert gas such as oxygen, nitrogen, or argon. These are appropriately selected according to the actual use environment of the test member 100.

  FIG. 1 is a photograph of the bubble 102 attached to the test surface of the test member 100 taken by the camera 20a. Specifically, when the inclination angle of the stage 18a is increased from 0 ° to 3 °, 6 °, 9 °, 12 °, and 15 °, an image of the bubble 102 attached to the test member having poor wettability Is an image of the bubble 102 attached to the test member having good wettability in the B column, and the G column. In the example of FIG. 1, the bubble 102 attached to the test member with poor wettability is attached to the test member 100 even if the inclination angle of the stage 18 a is increased to 15 °. On the other hand, the bubbles 102 attached to the test member having good wettability, when the inclination angle of the stage 18a is increased to 12 °, the test sample 100 is supplied as shown by an arrow in the figure. Moved outside the shooting range along the test surface.

According to the first embodiment of the present invention configured as described above, the following operational effects can be obtained. First, as shown in FIG. 1, the member wettability evaluation method described in this section is performed by immersing the test member 100 in a liquid, regardless of the wettability of the test member. The liquid W is brought into contact with the surface. At this time, in the case where the wettability of the test member 100 is poor, if bubbles are attached to the test surface 100a from below in the liquid, the test surface 100a and the liquid W as shown in FIG. The surface tension of the test surface 100a and the bubble 102 is superior to the surface tension of the test sample 100a, and the bubble 102 adheres to the test surface 100a in such a manner that it directly contacts the test member 100B having poor wettability. .
On the other hand, in the case where the wettability of the test member 100 is good, when bubbles are attached to the test surface 100a from below in the liquid, as shown in FIG. The surface tension between the test surface 100a and the liquid W is superior to the surface tension of the test surface 100a, and the bubbles 102 are mediated through the liquid layer Wa regardless of the presence or absence of the surface roughness of the test surface 100a and the surface roughness. It adheres to the test surface 100a in such a manner that it does not come into direct contact with the test surface 100a.

Here, when the test member 100G has good wettability as shown in FIG. 2B and the test surface 100a has irregularities, the droplets adhere to the test surface in the air. (Conventional droplet method) When the liquid adheres to the test surface 100a in advance, the liquid adhering to the irregularities of the test surface 100a adsorbs to each other, and the droplet contacts The corner drops. However, when the test surface 100a is in a dry state, the existing liquid and droplets do not adsorb, and sometimes the droplets dropped on the test surface are high, as in the case of poor wettability. is the contact angle appears (see figures theta _a of FIG. 5 described later). The member wettability evaluation method according to the first embodiment of the present invention provides an error in determining the wettability of a member due to the variation in contact angle caused by the presence or absence of the existing liquid on the test surface 100a. This is avoided by immersing the test member 100 in the liquid W and measuring the rising angle of the bubbles 102 in the liquid.

Further, in the member wettability evaluation method according to the first embodiment of the present invention, the atmospheric temperature is set within the range of the liquid phase temperature of the liquid W, so that it is based on the ascending angle of the bubbles 102 in the liquid. This makes it possible to determine the wettability, and avoids an error in determining the wettability of the member due to the variation in the contact angle caused by the presence or absence of the existing liquid on the test surface as described above.
In the member wettability evaluation method according to the first embodiment of the present invention, the volume of the bubble 102 is measured to an amount that can be determined according to the area of the test surface 100a of the test member 100, It is attached to the test surface. That is, if the bubble 012 is too large relative to the area of the test surface 100a, the bubble 102 cannot move up along the inclined test surface 100a, but the area of the test surface 100a of the test member 100 is not increased. By adhering the bubbles measured in accordance with the test surface to the test surface, regardless of the area of the test surface 100a of the test member 100, the operation of the bubble 102 on the test surface 100a was caused and stabilized in the liquid. It becomes possible to measure the angle of rise and fall of the bubble 102 that maintains its shape and size. As an example, in the case where so-called expanded metal or lath cut metal, which is a cell constituent member of a fuel cell, is used as a test member, the bubble 102 is measured and supplied to 20 ml or less because of the mesh pitch or the like. .

Therefore, as described above, according to the first embodiment of the present invention, it is possible to perform highly reliable wettability evaluation of a member.
In FIG. 5, as an example of the results of experiments conducted by the inventors, the results when a separator, which is a cell constituent member of a fuel cell, is used as a test member 100 are shown in a chart. In this example, the operating state of the cell equipped with this separator is 0.2 A / cm ² (hydrogen utilization rate fixed at 60%, cell temperature 80 ° C.), the ambient temperature is set to 25 ° C., and the tilt angle of the stage 18a The droplet contact angle θ _A according to the conventional droplet method when the rate of increase in the pressure is 1 ° / second and the limiting oxygen utilization rate Lor is 85%, 75%, 65%, 50%, and the embodiment of the present invention This is a comparison between the air contact angle θ _B of the bubbles obtained by the inspection apparatus 10 and the rolling angle θ _I obtained by the apparatus.
As is clear from this chart, according to the first embodiment of the present invention, the higher the critical oxygen utilization rate Lor and the better the power generation performance, the smaller the angle of elevation θ _{I of the} separator is, If the separator has good wettability, the wettability can be determined based on the principle that the power generation performance of the cell is improved.

Next, a second embodiment of the present invention will be described. The method for evaluating the wettability of a member according to the second embodiment of the present invention is shown in FIG. 6 in addition to the method of measuring the ascending angle of the bubbles 102 in the liquid according to the first embodiment of the present invention. As shown, the method includes a method in which a droplet is placed on the test surface 100a of the test member 100 and the wettability of the test member is evaluated based on the drop angle of the droplet.
Moreover, as a feature of the second embodiment of the present invention, the atmospheric temperature is set within the range of the liquid phase temperature of the droplets, or the atmospheric humidity is set within the range of 0% to 100% relative humidity. In addition, the type of atmospheric gas and a part or all of the pressure when the droplets are arranged on the test surface 100a are appropriately changed. Here, an organic solvent such as water or ethanol is used as the liquid. Further, the discharge pressure of the droplets on the test surface 100a is also changed as appropriate for the reasons described later. Furthermore, also in the second embodiment of the present invention, the volume of the droplet 104 is measured to an amount determined according to the area of the test surface 100a of the test member 100 and arranged on the test surface 100a. .

Now, according to the second embodiment of the present invention configured as described above, the following operational effects can be obtained. That is, in the member wettability evaluation method according to the second embodiment of the present invention, the atmospheric temperature within the range of the liquid phase temperature of the liquid, or the atmospheric humidity of 0% to 100% relative humidity, By placing the test member 100, the inspection environment according to the actual use conditions of the member is reproduced on the test surface.
Then, the droplet 104 is dropped on the sample surface 100a, the sample member 100 is tilted, and the wettability of the sample member 100 is evaluated based on the falling angle of the droplet 104. Further, when the entire test surface 100a is in a wet state under the set atmosphere environment, as in the first embodiment of the present invention, the bubble 102 is arranged on the test surface 100a, The wettability of the test member is evaluated on the basis of the rising angle of the bubble 102.

Further, in the second embodiment of the present invention, when the droplet 104 or the bubble 102 is arranged on the test surface 100a, the kind of atmospheric gas, the pressure, or the discharge pressure of the droplet with respect to the test surface is appropriately set. By changing, the inspection environment in accordance with the actual use conditions of the member is reproduced on the test surface 100a.
By the way, as shown in FIG. 6, when placing the droplet 104 on the test surface 100a, if the wettability of the test member 100 is poor, the liquid attached to the test surface 100a is repelled, Although it is well known that the contact angle of the droplet increases, the contact angle of the droplet 104 may increase even when the test member has good wettability. In other words, in the case of the test member 100 having good wettability and unevenness formed on the test surface 100a, when the droplet 104 is attached to the test surface 100a in the air, the liquid is attached to the test surface 100a in advance. In such a case, the liquid adhering to the unevenness of the test surface 100a and the liquid droplet adsorb each other, the liquid droplet 104 spreads on the test surface, and the contact angle decreases. On the other hand, when the test surface 100a is in a dry state, the existing liquid and the droplets 104 do not adsorb. Therefore, the spread of the liquid film is sometimes obstructed by the air pockets on the test surface 100a. A high contact angle may appear in the droplet 104 dropped on the test surface 100a as in the case where the property is poor. In view of this, the member wettability evaluation method according to the second embodiment of the present invention uses such a variation in contact angle due to the presence or absence of air accumulation on the test surface 100a as a droplet 104 on the test surface 100a. In other words, by appropriately increasing the discharge pressure to such an extent that the droplet 104 itself does not blow away, the irregular air pockets on the test surface 100a are repelled and the shape and size of the droplet 104 are maintained. Measure the falling angle.

  Also in the second embodiment of the present invention, the volume of the droplet 104 or the bubble 102 is measured to an amount that can be determined according to the area of the test surface 100a of the test member 100, and the test surface It is attached to 100a. That is, if the droplet 104 or the bubble 102 is too large relative to the area of the test surface 100a, the droplet 104 or the bubble 102 cannot drop or float along the sample surface 100a inclined, Regardless of whether the area of the test surface 100a of the test member 100 is wide or narrow, the droplets or bubbles measured according to the area of the test surface 100a of the test member 100 are attached to the test surface 100a. The movement of the droplet 104 or the bubble 102 on the surface 100a is caused, and the falling angle or the rising angle of the droplet 104 or the bubble 102 is measured.

  Furthermore, it is desirable to implement the member wettability evaluation method according to the first and second embodiments of the present invention during the manufacturing process of the hydrophilic or water repellent member. That is, in the manufacturing process of the hydrophilic or water-repellent member shown in FIG. 7, a material having a target wettability is examined (S50), and in order to obtain the wettability required for the member, the surface of the member is obtained by etching or the like. The reforming process is performed (S60). And by the wettability evaluation method for members according to the first and second embodiments of the present invention, the wettability of the test member subjected to the surface modification treatment is evaluated (S70), and according to the evaluation, A member having desired hydrophilicity or water repellency can be efficiently produced by appropriately further modifying the surface of the member.

It is the figure which image | photographed the bubble adhering to the test surface of a test member with the camera in the wettability evaluation method of the member which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the state which made the bubble adhere from the downward direction to the test surface of a test member in a liquid, (a) is the wettability of a test member, (b) is the wetness of a test member. The case where the property is good is shown. 1 is an overall view of an inspection apparatus according to a first embodiment of the present invention. It is a partially expanded view of the inspection apparatus which concerns on the 1st Embodiment of this invention. It is a graph which shows a test result when making a test member into the separator which is a cell structural member of a fuel cell. FIG. 5 is a schematic diagram showing a method for evaluating the wettability of a test member based on a drop angle of the liquid drop, by placing a droplet on the test surface of the test member, according to a second embodiment of the present invention. . It is the flowchart which included the wettability evaluation method of the member which concerns on the 1st, 2nd embodiment of this invention in the manufacturing process of a hydrophilic property or a water-repellent member.

Explanation of symbols

  100: Test member, 102: Bubble, θ: Rotation angle, W: Liquid

Claims (7)

A method for evaluating the wettability of a member, wherein the test member is immersed in a liquid, and the test surface is held horizontally with the test surface held downward to allow bubbles to adhere to the test surface from below. An evaluation method, wherein a member is tilted to measure a bubble rising angle, and the wettability of a test member is evaluated based on the rising angle. The evaluation method according to claim 1, wherein the ambient temperature is set within a range of a liquid phase temperature of the liquid. The evaluation method according to claim 1 or 2, wherein the volume of the bubble is measured to an amount determined according to the area of the test surface of the test member and attached to the test surface. A method for evaluating the wettability of a member, wherein droplets or bubbles are arranged on a test surface of a test member, and at this time, the ambient temperature is within the range of the liquid phase temperature of the droplets, or the relative humidity is An evaluation method characterized by evaluating the wettability of a test member in a humidity range of 0% or more and 100% or less with reference to a drop angle of the droplet or a bubble rise angle. The evaluation method according to claim 4, wherein the kind or pressure of the atmospheric gas or the discharge pressure of the liquid droplet on the test surface is appropriately changed when the liquid droplet or the bubble is arranged on the test surface. . The volume of the droplet or the bubble is measured to an amount determined according to the area of the test surface of the test member, and is disposed on the test surface. Evaluation methods. In order to obtain the wettability required for the member, the member surface was subjected to a modification treatment, and the surface modification treatment was performed by the wettability evaluation method for a test member according to any one of claims 1 to 6. A method for producing a hydrophilic or water-repellent member, comprising a step of evaluating the wettability of a test member and performing a further modification treatment of the member surface as appropriate according to the evaluation.