WO2019013285A1

WO2019013285A1 - Substance wettability evaluating method and evaluating device

Info

Publication number: WO2019013285A1
Application number: PCT/JP2018/026338
Authority: WO
Inventors: 田中信行; ▲高▼原順子; 粟津茜; 田中陽; 春園嘉英; 那須博光
Original assignee: 国立研究開発法人理化学研究所; 株式会社北川鉄工所
Priority date: 2017-07-14
Filing date: 2018-07-12
Publication date: 2019-01-17
Also published as: JP2019020228A; JP6792246B2

Abstract

The objective of the present invention is to provide a new method with which it is possible to evaluate the wettability of a substance. The present invention relates to a method for evaluating the wettability of a substance, comprising: spraying a gas onto a top surface of a substance of which the top surface is exposed; supplying a liquid in a position that is different from the gas spraying position, while continuing to spray the gas; stopping the supply of the liquid; after the supply of the liquid has stopped, observing at least one entity selected from a group comprising the size and shape of a region in which the top surface of the substance is exposed, and the behavior of the liquid; and evaluating the wettability of the liquid with respect to the substance on the basis of information obtained by means of said observation.

Description

Method and apparatus for evaluating wettability of substances

The present disclosure relates to a method for evaluating the wettability of a substance, and an evaluation device used therefor.

In the development of industrial products and quality control, it is very important to quantitatively evaluate the characteristics of the surface and interface of a substance. In the method of evaluating the surface of a substance, in the method of examining the physicochemical relationship between the liquid in contact with the substance surface, wettability is not only parent / hydrophobic but also adhesion, releasability, antifouling property, etc. It is closely related and is an extremely large factor in design and quality control.

As a method for evaluating the wettability of a substance, for example, a droplet is formed on the surface of a substance (object) to be evaluated, and a contact angle method in which the contact angle between the droplet and the object surface is evaluated. Captive bubble method for measuring the contact angle, or Wilhelmy method for measuring the surface tension itself at the interface between solid, liquid and gas. Etc. are known.

Also, the present inventors have conventionally covered the surface of a substance to be evaluated (object) with liquid, sprayed gas there to eliminate the liquid, and then measuring the dimensions of the area where the liquid was excluded. A non-contact evaluation method has been proposed for an object having a very high wettability such as a cell sheet which has been difficult to evaluate (Patent Document 1).

WO 2013/176264

The method of Patent Document 1 is very useful for the evaluation of the wettability when the object is, for example, a substance whose surface is wet or a substance which is already covered with a liquid, such as a cell sheet. However, the present inventors have found a new problem that the method can not sufficiently evaluate the wettability.

Thus, the present disclosure relates to a new method capable of evaluating the wettability of a substance and an apparatus used therefor.

The present disclosure relates, in one aspect, to a method of evaluating the wettability of a substance, including injecting a gas onto the surface of the substance whose surface is exposed, and while continuing the injection of the gas, the injection position of the gas and Is selected from the group consisting of supplying liquid to different positions, stopping supply of the liquid, size and shape of the exposed area of the substance after stopping supply of the liquid, and behavior of the liquid And a method of evaluating the wettability of the substance based on the information obtained by the observation.

The present disclosure relates, in another aspect, an apparatus for evaluating the wettability of a substance, comprising: means for injecting a gas onto the surface of the substance; means for supplying a liquid onto the surface of the substance; The present invention relates to an evaluation device including control means for controlling the gas injection means and the liquid supply means so as to supply liquid after the start of gas injection.

According to the present disclosure, in one aspect, a novel method capable of evaluating the wettability of a substance and an apparatus used therefor can be provided.

FIG. 1 is a schematic view showing an operation procedure in an embodiment of an evaluation method of the present disclosure. FIG. 2 is a flowchart showing an operation example in one embodiment of the evaluation method of the present disclosure. FIG. 3 is a flowchart showing an operation example in one embodiment of the evaluation method of the present disclosure. FIG. 4 is a schematic view showing the configuration of the measuring apparatus used in the example, FIG. 4A is a schematic view from the side, and FIG. 4B is a schematic view from the top. FIG. 5A is an image showing an example of wettability evaluation (VGP-treated polystyrene / ultrapure water) in Example 1. FIG. 5B is an image showing an example of wettability evaluation (untreated polystyrene / ultrapure water) in Example 1. FIG. 5C is an image showing an example of wettability evaluation (VGP-treated polystyrene / ultrapure water) in Comparative Example 1. FIG. 5D is an image showing an example of wettability evaluation (unprocessed polystyrene / ultrapure water) in Comparative Example 1. FIG. 6 is an image showing an example of wettability evaluation (VGP-treated polystyrene / liquid metal) in Example 2. FIG. 7 is an image showing an example of the evaluation of wettability (VGP-treated polystyrene / liquid metal) in Comparative Example 2. FIG. 8 is an image showing an example of the behavior of the liquid during the compressed air injection and after the injection stop according to the third embodiment. FIG. 9 is an image showing an example of the behavior of the liquid during compressed air injection in Example 4.

The present disclosure finds a new problem that when the wettability is evaluated in a state where the surface of the substance is covered with a liquid (for example, the method of Patent Document 1), the wettability may not be sufficiently evaluated. Based on In addition, the present disclosure makes the wettability of a substance more accurate by supplying a liquid to the surface of the substance while injecting a gas to the substance in a state where the surface is exposed (in contact with the outside air). Based on new findings that can be evaluated.

[Method of evaluating wettability]
The present disclosure relates, in one aspect, to a method of evaluating the wettability of a substance (the evaluation method of the present disclosure). The evaluation method of the present disclosure includes injecting a gas onto the surface of a substance whose surface is exposed, supplying a liquid to a position different from the injection position of the gas while continuing the injection of the gas, and supplying the liquid. Stopping the supply of the liquid, observing at least one selected from the group consisting of the size and shape of the exposed surface area of the substance, and the behavior of the liquid; Evaluating the wettability of the substance based on the obtained information.

According to the evaluation method of the present disclosure, in one or more embodiments, the substance in a state where the surface is exposed, that is, the substance in a state (for example, a dry state) before contact with a liquid to be evaluated for wettability. By injecting a gas directly to at least a part of the surface, it is possible to form an area (air purge area) in which substances other than the sprayed gas hardly or not come into contact with the surface. The liquid is covered with the liquid by supplying the liquid to the surface of the substance (outside of the air purge area) different from the gas injection position while continuing the injection of the gas to maintain the air purge area. An air purge area and an area covered with the sprayed gas (air purge area) are formed. When the supply of the liquid is stopped, the jet pressure of the injected gas and the surface tension between the liquid and the substance are balanced and in equilibrium. The formed air purge region prevents liquid from entering, thereby forming a blocked region with the surface of the material exposed. Since the size and shape of the blocking area are determined by the jet pressure of the injected gas and the surface tension between the liquid and the substance, the wettability of the substance is evaluated based on the size and the shape of the blocking area, etc. can do.

The wetting phenomenon has a hysteresis characteristic, and even when the same liquid and substance are used, the advancing contact angle when the area of the liquid spreads so as to cover the dry substance surface is that the substance surface is a liquid It is known that the angle is larger than the receding contact angle when the area of the liquid is reduced by sucking out the liquid from the state of being covered with. That is, when the wettability is evaluated in a state where the substance is wet with the liquid, the wettability is evaluated to be higher than when the liquid is brought into contact with the dry substance to evaluate the wettability. According to the method of the present disclosure, in one or more embodiments, the wettability of the substance to be evaluated in the exposed state, that is, the state before the substance is wetted with the liquid (for example, dry state) may be evaluated it can. Therefore, the wettability of the substance itself can be evaluated, so that the wettability of the substance can be evaluated more accurately.

According to the method of the present disclosure, in one or more embodiments, it is not necessary to cover the surface of the substance with liquid (not including the step of covering the surface of the substance with liquid) prior to the injection of the gas. For this reason, according to the method of the present disclosure, in one or more embodiments, when the liquid comes in contact with the substance, the physical properties of the substance may change or a film of the liquid may be formed on the surface of the substance. Even if they are present, they can be avoided to evaluate the wettability of the substance. In the evaluation method of the present disclosure, in one or more embodiments, when the substance to be evaluated is brought into contact with a liquid, the physical properties, characteristics and / or properties of the surface of the substance change, etc. Is very useful, for example, when the liquid and the substance cause a chemical reaction.

In the present disclosure, the “wettability evaluation” includes, in one or more embodiments, high / low affinity of the liquid to the surface of the substance, adhesion of the liquid, and / or ease of adhesion / adhesion. Evaluation of hardness is mentioned.

There are no particular limitations on the types and combinations of substances and liquids for which the wettability is evaluated in the evaluation method of the present disclosure. Examples of the liquid include, in one or more embodiments, aqueous media, oily media, organic solvents, liquid metals (molten metals), biological samples such as blood, and the like. The substance to be evaluated may be a solid substance such as a resin, an oily medium, metal, glass, and a biological sample such as skin in one or more embodiments, or may be a liquid as described above . The combination of the substance and the liquid can be appropriately selected from the above-mentioned substance, liquid and the like according to various conditions such as the material of the substance to be evaluated and the purpose of evaluating the wettability in one or more embodiments. Examples of combinations of substances and liquids include glass and aqueous medium, resin and aqueous medium, resin and liquid metal, metal and oil medium, metal and organic solvent, and the like as one or more embodiments.

[Gas injection]
The evaluation method of the present disclosure includes injecting a gas onto the surface of the substance whose wettability is to be evaluated, with the surface exposed.

The type of gas to be injected to the substance is not particularly limited, and can be appropriately set according to various conditions such as the material of the substance to be treated and the type of liquid covering the substance. As the gas, in one or more embodiments, one that does not adversely affect the substance (for example, a gas that does not change the property of the substance surface (for example, wettability)) is preferable. Gases, in one or more embodiments, include air and inert gases. The inert gas may, in one or more embodiments, include nitrogen, argon, and the like. The gas may be sterilized prior to use or may be used without sterilization.

The injection amount of gas (jet applied pressure) can be appropriately set in accordance with various conditions such as the material of the substance to be evaluated, the type of liquid covering the substance, and the thickness of the liquid. The gas jet application pressure is, in one or more embodiments, 1 kPa to 50 kPa. The gas may be injected such that, in one or more embodiments, the diameter of the air purge region formed immediately after injecting the gas is 2 mm to 30 mm.

The injection temperature of the gas can be appropriately set in accordance with various conditions such as the material of the substance to be evaluated, the type of liquid covering the substance, and the thickness of the liquid. The injection temperature of the gas may be room temperature in one or more non-limiting embodiments.

The gas is injected from the top of the substance to be evaluated in one or more embodiments. The gas may be injected from vertically above the substance or obliquely from above the substance in one or more embodiments. In one or more embodiments, the gas is preferably injected substantially vertically above the substance in order to more accurately evaluate the distribution of wettability.

In one or more embodiments, the injection of gas may be performed substantially at the center of the surface of the substance to be evaluated, or may be performed at other parts.

The method of injecting the gas is not particularly limited, and can be performed using an appropriate gas injection means in one or more embodiments. As the gas injection means, in one or more embodiments, a gas injection part and a gas supply part can be appropriately combined and used. As a gas injection part, the nozzle for gas is mentioned. Examples of the gas supply unit include a compressor and a gas cylinder. The gas injection unit and the gas supply unit can be connected via an appropriate gas flow path, and the gas can be injected from the gas injection unit. A filter such as a particle filter may be disposed between the gas injection unit and the gas supply unit in order to remove particles contained in the gas to be jetted and to reduce contamination to the substance to be evaluated. . The inner diameter of the gas nozzle can be appropriately set in accordance with various conditions such as the injection amount of gas. The internal diameter of the gas nozzle is, in one or more embodiments, 10 μm to 500 μm. The jetting distance of the gas (the distance from the surface of the substance to the tip of the jetting portion of the gas (for example, the tip of the nozzle)) can be appropriately set in accordance with various conditions such as the jetting amount of the gas. The injection distance of the gas is 0.5 mm to 15 mm in one or more embodiments.

The injection of the gas may be controlled by any suitable means for controlling the flow of gas, and in one or more embodiments, the electropneumatic regulator or solenoid valve may be suitably combined to control the injection of the gas. Control of the gas injection may be performed automatically or manually. For example, gas injection can be controlled automatically by controlling a regulator or a solenoid valve from a computer.

[Supply of liquid]
The evaluation method of the present disclosure includes supplying a liquid to the surface while continuing the above-described gas injection. The liquid is supplied to a position different from the injection position of the gas.

In the present disclosure, the “position different from the injection position of the gas” is, in one or more embodiments, formed at a position different from a position directly sprayed with the gas injected by the gas injection or formed by the gas injection. The outside of the air purge region may be mentioned. As a location to which the gas is directly sprayed, in one or more embodiments, when the gas is sprayed to the surface of the substance from the substantially vertical direction, a location where the air flow (jet) collides in the orthogonal direction to the surface of the substance is mentioned Be If the gas is being injected into the approximate center of the substance, in one or more embodiments, the liquid may be supplied from the outer edge / edge of the surface of the substance.

The amount of the liquid to be supplied is not particularly limited, and in one or more embodiments, the amount of the liquid layer (liquid film) to be formed on at least a part of the surface of the substance may be mentioned. It can be appropriately determined according to the surface area and the like. The amount of liquid supplied may be, in one or more embodiments, an amount such that a liquid layer with a thickness of 0.5 mm to 5 mm is formed when gas is not jetted (when the air purge region is not formed).

The method for supplying the liquid is not particularly limited, and in one or more embodiments, the method may be performed automatically by a nozzle or the like, or manually by a pipette or the like.

[Observation of Blocked Region or Behavior of Liquid, etc.]
The evaluation method of the present disclosure includes observing, after stopping supply of liquid, at least one selected from the group consisting of the size and shape of a surface exposed area (blocked area) in the substance and the behavior of the liquid. . When a predetermined amount of liquid is supplied from the outside of the air purge area to the surface of the substance on which the air purge area is formed by the jet of the injected gas, the jet pressure of the injected gas and the surface tension between the liquid and the substance It becomes substantially balanced and becomes substantially balanced. In that state, a surface exposed area and a liquid covered area are formed on the surface of the substance. In the present disclosure, the “area where the surface of the substance is exposed (blocked area)” refers to the area where the surface of the substance is exposed when the jet pressure and the surface tension are substantially in equilibrium.

In the present disclosure, the “area where the surface of the substance is exposed (blocked area)” includes, in one or more embodiments, the jet pressure of the injected gas, the surface tension between the liquid and the substance, and the like after the supply of the liquid is stopped. When the liquid crystal is substantially balanced to a substantially equilibrium state, the surface area of the substance is exposed, and the surface area of the substance not substantially in contact with the liquid. The size of the surface exposed area (blocked area) may, in one or more embodiments, be the area, diameter, etc.

The behavior of the liquid includes, in one or more embodiments, the speed at which the area or diameter of the blocking area decreases after gas injection has stopped, or the speed or appearance of the blocking area disappearing.

In one or more embodiments, the observation is performed during the injection of the gas (while injecting the gas to the substance) or after the stop of the injection of the gas, and from the point of evaluating the wettability more accurately, during the injection of the gas It may be carried out when the jet pressure and the surface tension are in equilibrium. In one or more embodiments, the observation may be performed both during and after the gas injection, or may be continuously performed from the gas injection and after the injection stop.

The observation may be performed visually in one or more embodiments, or may be performed by a CCD camera, a CMOS camera, a 3D scanner, or the like.

[Evaluation of wettability]
The evaluation method of the present disclosure includes evaluating the wettability of a substance based on the information obtained by the above observation.

In one or more non-limiting embodiments of the evaluation method of the present disclosure, when the same gas and liquid are used and measurement is performed under the same conditions (for example, injection pressure and liquid supply amount), during gas injection If the size and shape of the blocking area formed on the surface are large, it can be judged that the wettability is low (the affinity is low or adhesion is difficult), and if the size and shape of the blocking area are small, the wettability is high ( It can be judged that the affinity is high or easily attached. Similarly, if the size and shape of the blocking area remaining after gas injection stop is large or the speed of disappearance of the blocking area is low, it can be determined that the wettability is low (affinity is low or adhesion is difficult) and residual When the size and shape of the blocking area are small or the removal speed of the blocking area is fast, it can be judged that the wettability is high (the affinity is high or the adhesion is easy).

The evaluation method of the present disclosure may be performed in an inert gas atmosphere such as nitrogen gas in one or more embodiments.

[Evaluation device]
The present disclosure relates, in another aspect, to a device for evaluating the wettability of a substance (the evaluation device of the present disclosure). In one or more embodiments, an evaluation device of the present disclosure includes means for injecting a gas to a substance, means for supplying a liquid to the surface of the substance, and control means for controlling the gas ejecting means and the liquid supply means. The control means controls the gas injection means and the liquid supply means so as to supply the liquid to the surface of the substance while starting the gas injection to the substance and continuing the injection of the gas. Including. The evaluation device of the present disclosure can perform the evaluation of the wettability of a substance by the evaluation method of the present disclosure in one or more embodiments.

The liquid supply means, in one or more embodiments, is arranged to supply liquid to a position different from the position where the gas is injected by the gas injection means. Also, the control means may, in one or more embodiments, control the liquid supply means to supply the liquid to a position different from the position where the gas is injected by the gas injection means.

The evaluation device of the present disclosure may, in one or more embodiments, further comprise means for observing at least a portion of the surface of the material. At least a portion of the surface, in one or more embodiments, includes an exposed area (such as a blocked area or an air purge area) of the surface of the material. As the observation means, in one or more embodiments, one that detects light such as visible light, infrared light, ultraviolet light and the like can be mentioned. In addition, as the observation means, in one or more embodiments, a CCD camera, a CMOS camera, a high speed camera, a 3D scanner, etc. may be mentioned, and from the viewpoint of more accurate evaluation of wettability, high resolution One example is the use of a camera.

Hereinafter, a non-limiting embodiment of the evaluation method of the present disclosure will be described.

FIG. 1 is a schematic view showing an operation procedure in an embodiment of an evaluation method of the present disclosure. In FIGS. 1 (a) to 1 (e), the upper view is a schematic view from the side, and the lower view is a schematic view from the top.

First, a container 15 containing a substance 16 whose wettability is to be evaluated is disposed under the air nozzle 11 (FIG. 1 (a)). As the container 15 in which the substance 16 is disposed, in one or more embodiments, a container such as a petri dish or the like in which a liquid can be spread on the surface of the substance (a liquid layer can be formed) can be mentioned.

Next, a gas is jetted from the air nozzle 11 to the substance 16 in the state where the surface is exposed (FIG. 1 (b)). Since the surface of the substance 16 is exposed, the sprayed gas is directly sprayed to the surface of the substance 16. Thereby, a protection area (air purge area 17) by the air flow (jet) is formed on at least a part of the surface of the exposed substance 16. In the present embodiment, the gas injection position is fixed. Specifically, in the present embodiment, as shown in FIG. 1 (b), the injection of the gas is performed substantially vertically upward so that the injected gas is sprayed perpendicularly to the substantially central portion of the substance. I'm going from.

Then, the liquid 18 is supplied from the liquid supply nozzle 12 to the surface of the substance 16 (FIG. 1 (c)). The liquid 18 is preferably applied to a place different from the place where the gas is injected. In the present embodiment, the liquid 18 is supplied along the side wall surface of the container 15 in which the substance 16 is disposed. The liquid supply rate includes, in one or more embodiments, an amount capable of covering at least part or all of the surface of the substance.

The supplied liquid 18 moves on the surface of the substance 16. When the liquid 18 approaches a portion (in this embodiment, substantially the central portion of the substance, FIG. 1 (b) 17) where the gas is jetted, the surface tension of the liquid 18 and the substance 16 and the jet of the jetted gas The pressure flow prevents the liquid 18 from entering and forms an area where the surface exposure of the material is maintained. When the supply of the liquid 18 is stopped, the jet pressure of the injected gas and the surface tension between the liquid 18 and the substance 16 are in a balanced equilibrium state (FIG. 1 (d)). An area where X is exposed (blocked area X) and an area Y covered with liquid 18 are formed. The surface tension involved in the formation of the blocking zone X is the surface tension of the liquid 18 and the substance 16 not in contact with the liquid 18. Therefore, for example, the wettability of the substance 16 can be evaluated based on the size and the shape of the blocking area X, and the like. Also, at least a part or all of the behavior of the liquid 18 from the liquid supply start to the equilibrium state may be observed, and the wettability of the substance 16 may be evaluated based thereon.

Then, the gas injection is stopped. Then, since the jet pressure is lost, the equilibrium state is once canceled, and as a result, the liquid moves in the direction in which the size of the blocking area X becomes smaller. Once in equilibrium again, at least part of the blocking zone X remains and a residual blocking zone Z is formed (FIG. 1 (e)), or the blocking zone X disappears and the entire surface of the substance 16 is covered with the liquid 18. (Not shown). Since these are determined by the wettability of the substance, it is possible to observe the behavior of the blocking area X or the liquid 18 after stopping the injection of the gas, and to evaluate the wettability of the substance 16 based thereon.

In the present embodiment, the blocking area or the behavior of the liquid may be observed visually or may be observed using a camera or the like.

FIG. 2 is an example of a flowchart showing an operation example of another embodiment of the evaluation method of the present disclosure. In the example shown in FIG. 2, first, the injection of gas is started on the surface of the substance whose surface is exposed (S01). Then, while injecting a gas, a liquid is supplied to the surface of the substance (S02). After the supply of a predetermined amount of liquid is completed (S03) and the state of equilibrium is established, the size of the blocking area on the surface of the substance and / or the behavior of the liquid are observed (S04). Then, the gas injection is stopped (S05), and the wettability of the substance is evaluated based on the obtained information (the size of the blocking area and / or the behavior of the liquid, etc.) (S06).

FIG. 3 is an example of a flowchart showing an operation example of another embodiment of the evaluation method of the present disclosure. In the example shown in FIG. 3, first, imaging of an image of the surface of a substance is started, and acquisition of image information is started (S11). Next, in a state where acquisition of image information is continued, gas injection is started to the surface of the substance whose surface is exposed (S12). The liquid is supplied to the surface of the substance while continuing the gas injection (S13). Supply of a predetermined amount of liquid is stopped (S14), and after the equilibrium state is confirmed, gas injection is stopped (S15), and acquisition of image information is ended (S16). From the obtained image information, at least one of the size, shape and behavior of the blocking area during gas injection, and the size and behavior of the remaining blocking area after stopping injection is extracted based on these Evaluate the wettability of

A non-limiting embodiment of the measurement device of the present disclosure will be described.

FIGS. 4A and 4B are schematic views for explaining an embodiment of the configuration of the measurement apparatus (evaluation apparatus) of the present disclosure. FIG. 4A is a schematic view from the front, and FIG. 4B is a schematic view from the top.

As shown in FIGS. 4A and 4B, the measuring apparatus includes a gas jet nozzle 11, a liquid supply nozzle 12, a stand 13 for placing a container 15 capable of containing a substance to be evaluated, and a camera 14. The gas injection nozzle 11 is disposed vertically above the stand 13. The liquid supply nozzle 12 is arranged to be able to supply liquid to the substance disposed in the container 15 in an oblique direction.

The present disclosure further relates to one or more of the following non-limiting embodiments.
[1] A method for evaluating the wettability of a substance, which comprises
Injecting a gas onto a part of the surface of the substance whose surface is exposed,
Supplying liquid to a position different from the injection position of the gas while continuing the injection of the gas;
Stopping the supply of said liquid,
After stopping supply of the liquid, observing at least one selected from the group consisting of the size and shape of the surface exposed area of the substance and the behavior of the liquid, and information obtained by the observation Evaluation method including evaluating the wettability of the substance based on the
[2] The evaluation method according to [1], wherein the observation includes performing during the injection of the gas.
[3] includes stopping injection of the gas after stopping supply of the liquid,
The evaluation method according to [1] or [2], which comprises performing the observation after stopping the injection of the gas.
[4] The evaluation method according to any one of [1] to [3], wherein the injection of the gas includes injection in a direction substantially perpendicular to the surface of the substance.
[5] An apparatus for evaluating the wettability of a substance,
A means for injecting a gas onto the surface of the substance,
An evaluation apparatus, comprising: means for supplying a liquid to the surface of the substance; and control means for controlling the gas injection means and the liquid supply means so as to supply the liquid after gas injection to the substance is started.
[6] The evaluation device according to [5], wherein the control means controls the liquid supply means to supply the liquid to a position different from the position where the gas is injected by the gas injection means.
[7] The evaluation device according to [5] or [6], further comprising means for observing at least a part of the surface of the substance.

Hereinafter, the present disclosure will be described in more detail by way of examples, but these are illustrative and the present disclosure is not limited to these examples.

Example 1
The wettability of untreated polystyrene and vacuum plasma (VGP) treated polystyrene was evaluated using ultrapure water using the following apparatus.
<Substance>
The untreated polystyrene used the untreated dish (Product # 351007, FALCON, Corning Incorporated) (φ 60 mm, Material: Polystyrene, Surface Treatment: Not Treated).
The VGP-treated polystyrene used was a VGP-treated dish (Product # 353,002, FALCON, Corning Incorporated) (φ 60 mm, Material: Polystyrene, Surface Treatment: VGP Treated).

<Measurement device>
The measuring device comprises a gas jet nozzle, a camera and an illumination, and the gas jet nozzle is disposed vertically above the stage on which the substance is placed.
The camera used was an industrial camera (number of pixels: 4 M pixels, element: 1 "CMOS), the illumination used LED illumination, and the gas jet nozzle used a nozzle with an inner diameter of 500 μm.

<Evaluation of wettability>
The dish was placed in the measuring device, and the height of the gas jet nozzle (the distance between the jet port of the nozzle and the liquid surface) was set to be 15 mm. Compressed air with a nozzle pressure of 10 kPa was injected from the gas injection nozzle near the center of the dish surface to generate an air purge region at the center of the dish. In a state where the jet of compressed air was continued to generate an air purge region, 5 mL of ultrapure water was supplied by a pipette along the side wall surface of the dish. Then, after continuing injection of gas for about 5 seconds, injection was stopped. The results are shown in FIG. 5A or B.

(Comparative example 1)
The same procedure as in Example 1 was carried out except that 5 mL of ultrapure water was supplied to the surface of the substance to cover the entire surface of the substance with ultrapure water, and then compressed air was jetted from the nozzle for 10 seconds on the surface. The results are shown in FIG. 5C or D.

FIGS. 5A to 5D are images showing an example of the behavior of the ultrapure water (state of blocked area) from the start of compressed air injection to the end of a predetermined time after the injection is stopped. 5A is an image of VGP-treated polystyrene in Example 1, FIG. 5B is an image of untreated polystyrene in Example 1, FIG. 5C is an image of VGP-treated polystyrene in Comparative Example 1, and FIG. 5D is an untreated polystyrene in Comparative Example 1. It is an image. The images in FIGS. 5A to 5D are images every 0.8 to 0.9 seconds, and the lower left of each image is numbered along the captured time series. Further, the injection was stopped at the timing of the image 13 in FIGS. 5A to 5D.

As shown in FIGS. 5A and B, VGP treated polystyrene (FIG. 5A) and untreated polystyrene (FIG. 5B) differ in the size of the blocking region formed. That is, the size of the blocking region of VGP-treated polystyrene was smaller than that of untreated polystyrene. From these results, it was possible to evaluate that VGP-treated polystyrene has higher wettability to ultrapure water than untreated polystyrene.
VGP-treated polystyrene is known to have higher wettability to ultrapure water than untreated polystyrene. That is, according to the method of Example 1 in which the liquid was supplied after the gas was injected, the difference in the wettability of the substance could be evaluated.

As shown in FIGS. 5A to 5D, in Example 1 (FIGS. 5A and 5B) in which the liquid was supplied after the gas injection, the liquid was removed in Comparative Example 1 (FIGS. 5C and 5) in which the liquid was supplied before the compressed air injection. The size of the blocking area formed during the compressed air injection was larger than that of the blocked area (removing area). Further, in the case of VGP-treated polystyrene (FIGS. 5A and 5C), although the variation of the size of the blocking area was not seen in Example 1 after the jet of compressed air was stopped (FIG. 5A, images 13 to 16), In Comparative Example 1, the removed region disappeared (Figs. 5C, 13 to 16). From these facts, even when the same liquid and substance were used, different evaluations of wettability were obtained in Example 1 and Comparative Example 1. The wetting phenomenon has hysteresis characteristics, and even when the same liquid and substance are used, the advancing contact angle when the liquid spreads is the receding when the area is reduced by sucking out the liquid, etc. It is known that the angle is larger than the contact angle. That is, it is known that it is judged that the wettability is higher if the wettability is measured in the state where the substance is wetted with the liquid.
From the above results, it was possible to confirm that the wettability of the substance can be made more accurate by supplying the liquid after injecting the gas and evaluating the wettability.

Example 2
The wettability of the VGP-treated polystyrene was evaluated using liquid metal (Ga 61% -In 25% -Sn 13%).

The evaluation was carried out in the same manner as in Example 1 except that the following dish was used as a VGP treated dish, the pressure of compressed air sprayed onto the dish surface was 47 kPa, and the above liquid metal was used instead of ultrapure water. The The results are shown in FIG.
VGP treated dish: Product # 353 001 (FALCON, Corning Incorporated, φ 35 mm, Material: Polystyrene, Surface Treatment: VGP Treated)

(Comparative example 2)
The following dish is used as a VGP treated dish, 5 mL of liquid metal is supplied to the dish surface, the dish surface is covered with liquid metal, and then compressed air with a nozzle pressure of 47 kPa is jetted from the nozzle for 1 second; I did the same. The results are shown in FIG.
VGP treated dish: Product # 353 002 (FALCON, Corning Incorporated, φ 60 mm, Material: Polystyrene, Surface Treatment: VGP Treated)

FIG. 6 is an image showing an example of the behavior of the liquid metal from the liquid supply start to the stop of compressed air injection in Example 2, and FIG. 7 is the liquid from the start to stop of compressed air in Comparative Example 2. It is an image which shows an example of the behavior of metal. The lower left of each image in FIGS. 6 and 7 is numbered along the captured time series.

In FIG. 6, 1 to 7 are images during liquid metal supply, 9 is an image immediately before the injection stop, and 10 is an image immediately after the injection stop. As shown in FIG. 6, during the compressed air injection, a crescent-shaped blocking area was formed at the center of the dish, but the blocking area disappeared when the injection was stopped. Thus, by forming a blocking area on the surface of the polystyrene dish before liquid metal supply, the wettability of the liquid metal to polystyrene is evaluated based on the size of the blocking area to be formed and the behavior at the time when injection of compressed air is stopped. It can be said that you can do it.
On the other hand, in Comparative Example 2, as shown in FIG. 7, the liquid metal supplied in advance was in contact with the polystyrene surface to form a film. Therefore, even if compressed air is jetted after liquid metal supply, the liquid metal on the dish surface can not be removed (a removal area is not formed) (FIG. 7, images 2 to 4), and the liquid metal is wetted by polystyrene It was not possible to assess sex.

[Example 3]
The wettability of untreated and VGP treated polystyrene was evaluated using ultrapure water and 70% ethanol. The evaluation was performed in the same manner as in Example 1 except that the nozzle pressure was 30 kPa. The results are shown in Table 1 below and FIG.
<Substance>
Untreated polystyrene:
Untreated dish (Product # 351 007, FALCON, Corning Incorporated) (φ 60 mm, Material: Polystyrene, Surface Treatment: Not Treated)
・ VGP treated polystyrene:
VGP treated dish (Product # 353002, FALCON, Corning Incorporated) (φ 60 mm, Material: Polystyrene, Surface Treatment: VGP Treated)

FIG. 8 is an image showing an example of the behavior of the liquid during the compressed air injection or after the injection stop. As shown in Table 1 and FIG. 8, when different liquids are supplied to the same substance, the size of the blocking area formed by the jet of the compressed air, the blocking area after stopping the jet of the compressed air (liquid It can be confirmed that the behavior of (a), the presence or absence of the remaining blocking area (remaining area) and the size thereof are different. Further, the same can be said when the same liquid is supplied to different substances.
From these results, it was confirmed that the wettability of the substance can be compared by forming a blocking region in the substance before liquid supply and changing the type of liquid supplied.

Example 4
Liquid metal (Ga 61% -In 25% -Sn 13%) was used to evaluate the wettability of untreated and VGP-treated polystyrene. The evaluation was performed in the same manner as in Example 1 except that the nozzle pressure was 30 kPa and the liquid metal supply amount was 2 mL or 4 mL. The results are shown in FIG.

FIG. 9 is an image showing an example of the behavior of liquid metal during compressed air injection.
As shown in FIG. 9, in each case, a circular blocking area was formed at the center of the dish during the compressed air injection. Moreover, compared with the case where supply_amount | feed_rate of a liquid metal is 2 mL, the magnitude | size of the block area | region formed during compressed air injection was smaller in any of untreated polystyrene and VGP process polystyrene. Thereby, it was confirmed that the size of the blocking area formed during the compressed air injection was different by changing the supply amount of the liquid supplied to the substance.
Therefore, it was suggested that the wettability of the substance can be evaluated in more detail by forming a blocking region in the substance before liquid supply and changing the amount of liquid supplied.

Claims

A method of evaluating the wettability of a substance,
Injecting a gas onto a part of the surface of the substance whose surface is exposed,
Supplying liquid to a position different from the injection position of the gas while continuing the injection of the gas;
Stopping the supply of said liquid,
After stopping supply of the liquid, observing at least one selected from the group consisting of the size and shape of the surface exposed area of the substance and the behavior of the liquid, and information obtained by the observation Evaluation method including evaluating the wettability of the substance based on the
The evaluation method according to claim 1, wherein the observation includes performing during the injection of the gas.
After stopping the supply of the liquid, stopping the injection of the gas;
The evaluation method according to claim 1, comprising performing the observation after stopping the injection of the gas.
The evaluation method according to any one of claims 1 to 3, wherein the injection of the gas includes performing from substantially vertically above the surface of the substance.
An apparatus for evaluating the wettability of a substance,
A means for injecting a gas onto the surface of the substance,
The means for supplying liquid to the surface of the substance, and the gas injection means and the means for supplying liquid so as to supply the liquid to the surface of the substance after initiation of gas injection to the substance and continuing injection of gas. An evaluation device comprising control means for controlling
The evaluation device according to claim 5, wherein the control means includes controlling the liquid supply means to supply the liquid to a position different from the position where the gas is injected by the gas injection means.
The evaluation device according to claim 5 or 6, further comprising means for observing at least a part of the surface of the substance.