JP2019174114A - Method and apparatus for evaluating wettability of substance - Google Patents

Abstract

To provide a method capable of evaluating non-uniformity (wetting distribution) of wettability of a material surface.SOLUTION: Method for evaluating the wettability distribution of a substance, includes: injecting a gas against a liquid covering the surface of a substance; obtaining image information of a region (liquid removal region) where the liquid is removed from the surface of the substance by the gas injection during the gas injection; and evaluating the wettability distribution of the substance on the basis of the image information.SELECTED DRAWING: Figure 11

Description

  The present disclosure relates to a method for evaluating a wettability distribution of a substance and an apparatus capable of evaluating the wettability distribution of a substance.

  In the development and quality control of industrial products, it is very important to quantitatively evaluate the characteristics of material surfaces and interfaces. Among the methods for characterization of material surface, in the method of examining the physicochemical interaction between the contacting liquid and the material surface, the wettability is not only hydrophilic / hydrophobic but also adhesive, releasable, antifouling, etc. Are closely related to each other, which is an extremely large factor in design and quality control.

As a method for evaluating the wettability of a substance, for example, a contact angle method in which a droplet is formed on the surface of a substance (target object) to be evaluated and the contact angle between the droplet and the surface of the target object is evaluated. Captive bubble method to measure the contact angle by immersing in a liquid toward the surface, supplying air etc. from below and attaching it to the material surface, or Wilhelmy method to measure the surface tension itself at the interface of solid, liquid and gas Etc. are known.
In addition, the present inventors have covered the surface of a substance (object) to be evaluated with a liquid, ejected gas there to exclude the liquid, and then measured the dimensions of the area where the liquid has been excluded. A method of non-contact evaluation of an object having very high wettability such as a cell sheet that has been difficult to evaluate has been proposed (Patent Document 1).

WO2013 / 176264

  In various fields such as industrial, medical and biochemistry, the wettability of the surface of a substance is controlled, and the wettability is evaluated by the above-mentioned various methods on the surface with controlled wettability. Has been done. On the other hand, although it was thought that it was uniform by controlling the wettability, there are those that are not actually uniform, and those that are not uniform regardless of whether or not the wettability is controlled. However, in the evaluation of the wettability of a substance, measurement is usually performed on the assumption that the wettability of the surface of the target substance is uniform, as in the method of Patent Document 1, for example.

  Therefore, the present disclosure relates to a method capable of evaluating non-uniformity of wettability (wetability distribution) of a material surface and an apparatus used therefor.

  In one aspect, the present disclosure is a method for evaluating a wettability distribution of a substance, wherein a gas is ejected to a liquid covering a surface of the substance, and the liquid is removed from the surface of the substance by the ejection of the gas. The present invention relates to an evaluation method including obtaining image information of a region (liquid removal region) to be performed during jetting of the gas and evaluating a wettability distribution of a substance based on the image information.

  In one aspect, the present disclosure is an apparatus for evaluating a wettability distribution of a substance by injecting a gas onto a surface of a substance covered with a liquid, the means for injecting the gas, An evaluation apparatus comprising: means for detecting a region where the liquid is removed from the surface of the substance by jetting; and an illumination, wherein an optical axis of the illumination coincides with an optical axis of the detection means or an axis of the nozzle .

  According to the present disclosure, in one aspect, the wettability distribution (non-uniformity) of the substance surface can be evaluated.

FIG. 1 is a flowchart illustrating an example of an operation example according to an embodiment of the evaluation method of the present disclosure. FIG. 2 is a flowchart illustrating an example of an operation example in another embodiment of the evaluation method of the present disclosure. FIG. 3 is an example of a dish image used in the first embodiment. FIG. 4 is an example of an image of the measuring apparatus used in Example 1. FIG. 5 is an example of an image showing the result of evaluation of wettability distribution in Example 1 (applied pressure: 5 kPa). FIG. 6 is an example of an image showing the result of evaluation of wettability distribution in Example 1 (applied pressure: 10 kPa). FIG. 7 is an example of an image showing the result of evaluating the wettability distribution in Example 1 (applied pressure: 20 kPa). FIG. 8 is a schematic view showing the positions of the hydrophobic surface and the hydrophilic surface of the dish used in Example 2. FIG. 9 is an example of an image showing a result of evaluation of wettability distribution in Example 2. FIG. 10 is a schematic view showing the positions of the hydrophobic surface and the hydrophilic surface of the dish used in Example 3. FIG. 11 is an example of an image showing a result of evaluation of wettability distribution in Example 3.

  According to the present disclosure, the distribution of wettability on the surface of a substance is performed by detecting an area (liquid removal area) in which the liquid is removed by jetting the gas with respect to the liquid covering the surface of the substance during the jetting of the gas. Based on the new knowledge that can be evaluated. In addition, the present disclosure also measures the liquid removal area over time because the behavior in which the liquid is removed or the surface is covered again by gas injection varies according to the wettability distribution. This is based on the new knowledge that the wettability distribution on the surface of the substance can be evaluated by detecting the shape change of the material (for example, calculating the time change rate of the curvature distribution of the outer periphery).

Although it is not clear to the mechanism which can evaluate the distribution of wettability by the method of this indication, it estimates as follows.
When gas is injected onto the surface of a substance covered with liquid, immediately after injection, the liquid part (jet impingement part) directly hit by the jet is blown away radially, and the wettability of the substance surface over time (physics between the liquid and substance) The liquid moves according to the chemical interaction and the surface tension of the liquid), and reaches an equilibrium state where the interaction, surface tension and jet pressure are balanced. Further, the behavior of the region where the liquid is removed before reaching the equilibrium state depends on the wettability of the surface. Specifically, the inventors of the present invention have proposed that the radius of the region shape from which the liquid is removed by jetting the gas (the radius of the circle when a part of the liquid removal region forms a part of a circle) and the contact angle. And have a correlation. For this reason, the region shape from which the liquid is removed during gas injection (particularly the process until equilibrium is reached) is detected over time, and the curvature of the region shape, for example, is calculated based on the detection result. If the wettability of the surface is not uniform, there will be a difference in the shape of the removed area, so the behavior of the liquid to be removed is acquired as image information, and further, the curvature of the removed area shape is calculated, and the entire surface is wetted. Sex distribution can be evaluated. On the other hand, if the wettability of the surface is uniform, substantially one curvature is derived, and as a result, it can be evaluated that the wettability of the entire surface is uniform. However, the present disclosure need not be interpreted as being limited to these mechanisms.

[Evaluation method of wettability distribution]
In one aspect, the present disclosure is a method for evaluating a wettability distribution of a substance, wherein a gas is ejected to a liquid covering a surface of the substance, and the liquid is removed from the surface of the substance by the ejection of the gas. An evaluation method (evaluation method of the present disclosure) including obtaining image information of a region (liquid removal region) to be performed during jetting of the gas and evaluating a wettability distribution of a substance based on the image information About. According to the evaluation method of the present disclosure, in one or a plurality of embodiments, the wettability distribution of a substance to be evaluated can be evaluated in a non-contact manner.

  In this disclosure, “evaluating the wettability distribution” includes, in one or a plurality of embodiments, evaluating the presence / absence of wettability distribution on the substance surface (whether the wettability is uniform), hydrophilicity on the substance surface Examples include observing the distribution of the surface and the hydrophobic surface, obtaining the distribution of the contact angle on the material surface, or patterning.

[Gas injection]
The evaluation method of the present disclosure includes injecting a gas against a liquid covering the surface of the substance.

  The type of liquid that covers the surface of the substance is not particularly limited. The liquid includes an aqueous medium in one or more embodiments. In one or a plurality of embodiments, the aqueous medium may be composed of water, and may contain other components. Aqueous media include, in one or more embodiments, water, buffers, and liquid culture media. Examples of water include distilled water, ion-exchanged water, and ultrapure water in one or more embodiments. The liquid may be an organic solvent in one or more other embodiments that are not particularly limited. Examples of the organic solvent include diiodomethane and n-hexadecane in one or more embodiments.

  The liquid is arrange | positioned so that the whole surface of the substance used as evaluation object may be covered in one or some embodiment. The thickness of the liquid layer covering the surface of the substance is not particularly limited and can be appropriately determined according to the substance to be evaluated. The thickness of the liquid layer is 0.5 mm to 5 mm in one or more embodiments.

  In one or a plurality of embodiments, the evaluation method of the present disclosure may include disposing a liquid on the surface of the substance to be evaluated so that the surface of the substance is covered with the liquid, or the surface is previously covered with the liquid. Substances may be used.

  The type of gas injected onto the substance is not particularly limited, and can be set as appropriate according to various conditions such as the material of the substance to be evaluated and the type of liquid covering the substance. The gas is preferably one that does not adversely affect the substance in one or more embodiments. Examples of the gas include air and an inert gas in one or more embodiments. Examples of the inert gas include nitrogen and argon in one or more embodiments. The gas may be used after sterilization or may be used without sterilization.

  The gas injection amount (jet application pressure) can be appropriately set according to 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. In one or a plurality of embodiments, the gas jet pressure is 1 kPa to 50 kPa. In one or a plurality of embodiments, the gas may be injected so that the diameter of the region of the liquid that is removed immediately after the gas injection is 2 mm to 10 mm.

  The jetting temperature of the gas can be appropriately set according to 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 jetting temperature of the gas is not particularly limited, and one or more embodiments include room temperature.

  In one or a plurality of embodiments, the gas is injected from above the substance to be evaluated. In one or a plurality of embodiments, the gas may be injected from vertically above the substance, or may be injected obliquely from above the substance. In one or a plurality of embodiments, it is preferable that the gas is injected from substantially vertically above the substance from the viewpoint of more accurately evaluating the wettability distribution.

  In one or a plurality of embodiments, the gas injection may be performed at a substantially central portion of the substance to be evaluated, or may be other than the central portion.

  In one or a plurality of embodiments, the gas injection may be performed at only one place, or may be performed at a plurality of places so as to perform scanning.

  In one or a plurality of embodiments, gas injection may be performed once, or may be performed twice or more. In one or a plurality of embodiments, the gas injection may be performed continuously or intermittently. In one or a plurality of embodiments, the gas injection time is 0.1 second to 5 seconds.

  The method for injecting the gas is not particularly limited, and in one or a plurality of embodiments, it can be performed using an appropriate gas injection means. As the gas injection means, in one or a plurality of embodiments, a gas injection unit and a gas supply unit can be used in appropriate combination. An example of the gas injection unit is a gas nozzle. Examples of the gas supply unit include a compressor and a gas cylinder. The gas injection unit and the gas supply unit are 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 is placed between the gas injection unit and the gas supply unit in order to remove particles contained in the gas to be injected and reduce contamination to the substance to be evaluated. Also good. The inner diameter of the gas nozzle can be appropriately set according to various conditions such as a gas injection amount. The internal diameter of the nozzle for gas is 10 micrometers-100 micrometers in one or some embodiment. The gas injection distance (distance from the surface of the liquid layer to the tip of the gas injection portion (for example, the tip of the nozzle)) can be appropriately set according to various conditions such as the amount of gas injection. In one or a plurality of embodiments, the gas injection distance is 0.5 mm to 5 mm.

  The gas injection can be controlled by an appropriate means for controlling the gas flow. In one or a plurality of embodiments, the gas injection can be controlled by appropriately combining an electropneumatic regulator and an electromagnetic valve. The control of gas injection may be performed automatically or manually. For example, the injection of gas can be automatically controlled by controlling a regulator or a solenoid valve from a computer.

[Detection of removal area]
The evaluation method of the present disclosure includes obtaining image information of a region (liquid removal region) where the liquid is removed from the surface of the substance by gas injection. In the evaluation method of the present disclosure, the acquisition of the image information is performed at least during gas injection. According to the evaluation method of the present disclosure, the image information of the liquid removal region is obtained at least during the jetting of gas, so that the wettability distribution on the substance surface can be evaluated.

  In the present disclosure, the “region from which the liquid is removed (liquid removal region)” is, in one or a plurality of embodiments, the liquid is removed from the surface of the substance by injecting a gas onto the surface of the substance covered with the liquid. Range, a range where the liquid level is lowered, or a portion where the substance is exposed from the liquid.

  Examples of the liquid removal region detected in the evaluation method of the present disclosure include the shape and area of the liquid removal region in one or a plurality of embodiments.

  In the present disclosure, the “image information of the liquid removal region” includes a moving image obtained by capturing an image of the region including the liquid removal region, a still image, or the like in one or a plurality of embodiments. When the image information is a still image, the acquisition of the image information may be performed continuously or intermittently in one or a plurality of embodiments. The acquisition of the image information may be performed once in one or a plurality of embodiments, or may be performed two or more times. Acquisition of image information may be performed automatically or manually in one or a plurality of embodiments.

  The image information of the liquid removal region may be acquired at least during the gas injection. In one or a plurality of embodiments, the image information may be acquired before the injection starts and after the injection ends, or immediately after the injection starts. It may be done until later. Further, the acquisition of the image information of the liquid removal region may be continuously performed even after the ejection is completed, or may be performed in an equilibrium state.

  In one or a plurality of embodiments, the image information of the liquid removal region can be acquired using a device that detects light such as visible light, infrared light, and ultraviolet light. In one or a plurality of embodiments, acquisition of image information includes a CCD camera, a CMOS camera, a 3D scanner, and the like. From the viewpoint of evaluating the wettability distribution with higher accuracy, it is preferable to use a high-resolution camera.

  From the viewpoint of evaluating the wettability distribution with higher accuracy, it is preferable to acquire the image information of the liquid removal region in a state where the substance to be evaluated is irradiated with light. From the viewpoint of evaluating the wettability distribution with higher accuracy, the optical axis of the illumination for irradiating light should be matched with the optical axis of the imaging means for detecting or the axis of the nozzle for injecting the gas. preferable. The illumination is not particularly limited, and an LED is preferable from the viewpoint of evaluating the wettability distribution with higher accuracy.

(Evaluation of wettability distribution)
The evaluation method of the present disclosure includes evaluating the wettability distribution of a substance based on the acquired image information.

  In one or a plurality of embodiments, the evaluation of the wettability distribution includes detecting shape information extracted from at least one of the three-dimensional shape and the planar shape of the liquid removal region from the image information. As one or a plurality of embodiments, the shape information includes one or more curvatures obtained from at least one of a three-dimensional outer peripheral curved surface and a planar outer peripheral curve. In the evaluation of the wettability distribution, in one or a plurality of embodiments, one or more curvatures obtained from a three-dimensional outer peripheral curved surface or a planar outer peripheral curve are extracted from the three-dimensional shape or planar shape of the liquid removal region. It may include.

  In one or a plurality of embodiments, the evaluation of the wettability distribution may include measuring a temporal change or a temporal change rate of the liquid removal region from the image information. When the image information is a still image, the temporal change is measured by detecting shape information from a plurality of pieces of image information having different elapsed times from the start of detection in one or a plurality of embodiments. This can be done by measuring the temporal change of. When the image information is a moving image, the temporal change is measured in one or a plurality of embodiments by detecting a plurality of shape information having different elapsed times from the detection start time from the image information, and detecting the difference between the detected shape information. It can be performed by measuring a temporal change or a time change rate.

  The evaluation of the wettability distribution of the substance based on the detected area can be performed using commercially available image processing software or the like in one or a plurality of embodiments.

  The substance to be evaluated in the evaluation method of the present disclosure is not particularly limited, and examples include substances that require wettability evaluation. Examples of the substance include instruments and materials used in medicine including basic research in chemistry, biology, drug discovery, and regenerative medicine, and industrial products in one or a plurality of embodiments. Among them, as the substance, in one or a plurality of embodiments, a substance whose surface is originally wet, such as a hydrogel or a cultured cell, is preferable. By evaluating the wettability distribution of the substance by the evaluation method of the present disclosure, it becomes possible to conduct an experimental study using a substance having a more uniform wettability, and as a result, further improvement of the research result is expected.

  The evaluation method of this indication can be used for evaluation of wettability distribution of the surface of a cell sheet etc. in one or a plurality of embodiments. Moreover, since the evaluation method of this indication can evaluate the wettability distribution of a substance, in one or some embodiment, the individual wettability in a cell population can be evaluated.

[Manufacturing method including evaluation of wettability distribution]
The evaluation method of the present disclosure can be used for detection of surface treatment unevenness of a substance in one or a plurality of embodiments. By evaluating the wettability distribution of a substance by the evaluation method of the present disclosure, it is possible to manufacture a substance that has been subjected to a surface treatment with better uniformity. Thus, in another aspect, the present disclosure relates to a method of manufacturing a material that includes evaluating the wettability distribution of the material by the evaluation method of the present disclosure. The manufacturing method of the present disclosure may further include uniformizing the wettability distribution on the surface of the substance based on the evaluation of the wettability distribution based on the evaluation method of the present disclosure.

[Evaluation equipment]
In one aspect, the present disclosure is an apparatus for evaluating a wettability distribution of a substance by injecting a gas onto a surface of a substance covered with a liquid, the means for injecting the gas, The evaluation apparatus (this book) includes means for detecting an area where the liquid is removed from the surface of the substance by jetting, and illumination, and an optical axis of the illumination coincides with an optical axis of the detection means or an axis of the nozzle. Disclosure evaluation apparatus).

  In one or a plurality of embodiments, the evaluation apparatus of the present disclosure may include means for calculating the wettability distribution of the surface of the substance to be evaluated based on the information detected by the detection means.

Hereinafter, a non-limiting embodiment of the evaluation method of the present disclosure will be described.
FIG. 1 is a flowchart illustrating an operation example of an embodiment of the evaluation method of the present disclosure. In the example shown in FIG. 1, first, imaging of a moving image of the surface of a substance is started, and acquisition of image information is started (S01). Next, in a state where the acquisition of the image information is continued, the injection of gas into the liquid covering the material surface is started (S02). The gas injection is stopped (S03) and the acquisition of the image information is ended (S04). From the obtained image information, the three-dimensional shape, the planar shape, or both of the liquid removal region are extracted, and the shape information extracted from these shapes is detected (S05). The wettability distribution of the substance is evaluated from the detected shape information (S06).

  Moreover, the evaluation method of this indication may evaluate wettability distribution from several shape information, as shown in FIG. FIG. 2 is a flowchart illustrating an operation example of another embodiment of the evaluation method of the present disclosure. First, acquisition of image information (S01), gas injection start (S02), injection stop (S03), image information acquisition end (S04), and shape information detection from image information (S05), as in FIG. I do. Next, it is determined whether the wettability distribution can be evaluated based on the detected shape information (SS06). If it is determined that the wettability distribution can be evaluated, the wettability distribution is evaluated (S07). On the other hand, if it is determined that it is difficult to evaluate the wettability distribution only with the detected shape information, shape information having a different elapsed time is detected from the image information (S08), and the time of the liquid removal region is determined from the shape information having a different elapsed time. The change is measured (S09). Based on the obtained temporal change, it is determined whether the wettability distribution can be evaluated (SS06). If it is determined that the wettability distribution can be evaluated, the wettability distribution is evaluated (S07). On the other hand, if it is determined that it is difficult to evaluate the wettability distribution, detection of shape information with different elapsed times from image information (S08) and measurement of temporal change of the liquid removal region from shape information with different elapsed times (S09) Repeat.

  By properly using the processing of FIG. 1 or FIG. 2, it is possible to perform evaluation from rough wettability distribution evaluation (presence / absence of wettability distribution) to more detailed wettability distribution evaluation.

The present disclosure further relates to one or more of the following non-limiting embodiments.
[1] A method for evaluating the wettability distribution of a substance,
Injecting a gas against the liquid covering the surface of the substance,
Obtaining image information of a region (liquid removal region) where the liquid is removed from the surface of the substance by jetting the gas during jetting of the gas, and evaluating the wettability distribution of the substance based on the image information An evaluation method including:
[2] The evaluation method according to [1], wherein the evaluation of the wettability distribution includes detecting shape information extracted from at least one of a three-dimensional shape and a planar shape of the liquid removal region of the image information.
[3] The evaluation method according to [2], wherein the shape information is one or two or more curvatures obtained from the three-dimensional outer peripheral curved surface or the planar outer peripheral curve.
[4] The evaluation method according to any one of [1] to [3], wherein the image information is a moving image obtained by imaging an area including the liquid removal area in the substance, or one or more still images.
[5] The evaluation method according to any one of [1] to [4], wherein the evaluation of the wettability distribution includes measuring a temporal change of the liquid removal region from the image information.
[6] The acquisition of the image information includes imaging the substance in a state where the substance is irradiated with light,
The evaluation method according to any one of [1] to [5], wherein an optical axis of illumination that emits the light coincides with an optical axis of an imaging unit that performs the imaging or an axis of a nozzle that ejects the gas.
[7] A method for producing a substance, comprising evaluating the wettability distribution of the substance by the evaluation method according to any one of [1] to [6].
[8] An apparatus for evaluating the wettability distribution of a substance by injecting a gas onto the surface of the substance covered with a liquid,
Means for injecting the gas;
Means for detecting a region where the liquid is removed from the surface of the substance by the gas jet, and illumination,
The evaluation apparatus, wherein an optical axis of the illumination coincides with an optical axis of the detection unit or an axis of the nozzle.
[9] The evaluation apparatus according to [8], further including means for measuring one or more curvatures of the outer periphery of the liquid removal region detected by the detection means.

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

Example 1
[Evaluation of wettability distribution 1]
The following apparatus was used to evaluate the following wettability distribution on the dish surface.
<Dish>
After pasting semi-circular silicone rubber on the surface of the dish (Product # 4305589, Becton, Dicinson and Company) (φ60 mm, Material: Polystyrene, Surface Treatment: Not Treated), nitrogen gas plasma is not applied to the dish surface. The hydrophilic treatment was performed. Thereafter, by removing the silicone rubber, the surface that has been hydrophilized (hydrophilic surface, contact angle: 73.8 °) and the surface that has not been hydrophilized (hydrophobic surface, contact angle: 89.1 °) A dish (FIG. 3) having
<Measurement device>
A measuring apparatus having the configuration shown in FIG. 4 was prepared. The camera used was an industrial camera (number of pixels: 4M pixels, element: 1 "CMOS), the illumination used was LED illumination, and the nozzle used was a nozzle with an inner diameter of 500 μm. The apparatus was set so that the optical axis of the camera and the optical axis of the illumination were coaxial.

<Measurement of wettability distribution>
3.3 ml of milliQ was placed in the dish (liquid thickness: 1.5 mm). The nozzle was placed at the upper center of the dish so that the distance between the dish surface and the tip of the nozzle was 15 mm, and air was applied from the nozzle to the dish for 1 second. The applied pressure of the nozzle was set to 5, 10 or 20 kPa. The results are shown in FIGS.

5 to 7 are examples of images at intervals of 5.6 milliseconds from immediately after the start of injection to immediately before the end of injection, and the respective nozzle application pressures are 5 kPa, 10 kPa, and 20 kPa in order. 5 and 7, the dish is arranged so that the surface subjected to the hydrophilic treatment is the left half, and in FIG. 6, the dish is arranged so that the surface subjected to the hydrophilic treatment is the right half. Numbers are assigned to the upper left of each image in FIGS.
As shown in FIGS. 5 to 7, in any surface having different wettability at any applied pressure, on a surface with low wettability (surface not subjected to hydrophilization treatment), with application of air, Expansion of the liquid removal area was confirmed. On the other hand, on the surface with good wettability (surface subjected to the hydrophilization treatment), the enlargement of the removal region was hardly observed, and eventually the liquid remained on all the surfaces with good wettability. In other words, by confirming the change in the liquid removal area during the jet of gas to the liquid covering the surface of the substance, the difference (distribution) in the wettability of the dish surface is visualized by the area (removal area) from which the liquid has been removed. I was able to do it.

(Example 2)
[Evaluation of wettability distribution 2]
This was performed in the same manner as in Example 1 except that a dish having a hydrophilic surface shown in FIG. 8 was used locally and the nozzle applied pressure was 10 kPa. The result is shown in FIG.
<Dish>
Silicone rubber from which circles of φ2 mm, φ8 mm, φ6 mm, and φ4 mm are cut out every 90 ° on the circumference of φ16 mm is obtained from Dish (Product # 351008, Becton, Dicinson and Company) (φ35 mm, Material: Polystyrene, Surface Treat: After being pasted on the dished surface, nitrogen gas plasma was sprayed evenly on the dish surface to perform a hydrophilic treatment. Then, the dish (FIG. 8) which has locally the surface (hydrophilic surface) hydrophilized by removing silicone rubber was prepared. In FIG. 8, the grayed out portion is a portion subjected to the hydrophilic treatment.

FIG. 9 shows an example of an image (A) immediately after spray application, an image (B) after 60 milliseconds of spray application, and an image (C) 500 milliseconds after the end of spray application in order from the left. In the lower image in FIG. 9, the position of the region subjected to the hydrophilic treatment is shown in the upper image.
As shown in FIG. 9, the liquid is removed in a circle immediately after the injection application (A), but as time passes, the liquid stays in a region with good wettability and 500 milliseconds after the end of the injection (C). Then, it was confirmed that the liquid remained on the surface subjected to the hydrophilization treatment (surface with good wettability, lower broken line). Thereby, even on a surface where regions with different wettability exist locally, the wettability difference (distribution) of the target surface could be evaluated by the method of the present disclosure.

(Example 3)
[Evaluation of wettability distribution 3]
As shown in FIG. 10, the same procedure as in Example 2 was performed except that a dish having a hydrophobic surface locally was used and the nozzle applied pressure was set to 20 kPa. The result is shown in FIG.
<Dish>
A circular silicone rubber of φ2 mm, φ8 mm, φ6 mm, and φ4 mm is made from a dish (Product # 351008, Becton, Dicinson and Company) (φ35 mm, Material: Polystyrene, Surface Treatment: NOT Treated) φ10 mm above the center of the circle (diameter 10 mm). Then, a hydrophilization treatment was performed by spraying nitrogen gas plasma evenly on the dish surface. Then, the dish (FIG. 10) which has locally the surface (hydrophobic surface) which has not been hydrophilized by preparing silicone rubber was prepared. The part filled with gray in FIG. 10 is a part subjected to the hydrophilic treatment.

FIG. 11 shows an example of an image (A) immediately after spray application, an image (B) 150 milliseconds after the spray application, and an image (C) 380 milliseconds after the end of spray application in order from the left. In the lower image of FIG. 9, the position of the region where the hydrophilic treatment is not performed is shown in the upper image.
As shown in FIG. 11, the liquid is removed in a circle immediately after the injection application (A), but from the surface that has not been hydrophilized with the passage of time (surface with poor wettability, broken line in the figure). It was confirmed that the liquid was removed and the liquid remained in the other region (surface subjected to the hydrophilic treatment). Thereby, even on a surface where regions with different wettability exist locally, the wettability difference (distribution) of the target surface could be evaluated by the method of the present disclosure.

Claims (9)

A method for evaluating the wettability distribution of a substance,
Injecting a gas against the liquid covering the surface of the substance,
Obtaining image information of a region (liquid removal region) where the liquid is removed from the surface of the substance by jetting the gas during jetting of the gas, and evaluating the wettability distribution of the substance based on the image information An evaluation method including:   The evaluation method according to claim 1, wherein the evaluation of the wettability distribution includes detecting shape information extracted from a three-dimensional shape or a planar shape of the liquid removal region of the image information.   The evaluation method according to claim 2, wherein the shape information is one or more curvatures obtained from the outer peripheral curved surface of the three-dimensional shape or the outer peripheral curve of the planar shape.   The evaluation method according to claim 1, wherein the image information is a moving image obtained by imaging an area including the liquid removal area in the substance, or one or more still images.   The evaluation method according to claim 1, wherein the evaluation of the wettability distribution includes measuring a temporal change of the liquid removal region from the image information. Acquisition of the image information includes imaging the substance in a state in which the substance is irradiated with light,
The evaluation method according to claim 1, wherein an optical axis of illumination for irradiating the light coincides with an optical axis of an imaging unit that performs the imaging or an axis of a nozzle that ejects the gas.   A method for producing a substance, comprising evaluating the wettability distribution of the substance by the evaluation method according to claim 1. An apparatus for evaluating the wettability distribution of a substance by injecting a gas onto the surface of the substance covered with a liquid,
Means for injecting the gas;
Means for detecting a region where the liquid is removed from the surface of the substance by the gas jet, and illumination,
The evaluation apparatus, wherein an optical axis of the illumination coincides with an optical axis of the detection unit or an axis of the nozzle.   The evaluation apparatus according to claim 8, further comprising means for measuring one or more curvatures of the outer periphery of the liquid removal area detected by the detection means.