JP2007232449A - Separation method of liquid droplet and inspection method of liquid droplet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separation method of a liquid droplet which enables the simple separation of the liquid droplet corresponding to its properties in a short time, and the inspection method of the liquid droplet which enables the simple inspection of whether the liquid droplet has predetermined properties or the concentration or the like of a solute. <P>SOLUTION: When the liquid droplet is allowed to fall along a slope having a plurality of regions different in the falling angle of the liquid droplet, the falling direction of the liquid droplet changes at the boundary of the mutual regions different in the falling angle. As a result, the liquid droplet arrives at a position different from that in the case where the liquid droplet falls along the slope toward a just-under direction according to gravity and its arrival point changes in dependence on properties such as the size of the liquid droplet or the concentration of the solute. The liquid droplet is separated from its properties by utilizing this phenomenon to inspect whether the liquid droplet has predetermined properties. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for separating and inspecting a droplet, and an instrument used therefor.

  Liquid component separation techniques are required in various academic and manufacturing industries, and many methods have been developed so far. Among them, the most common technique is to utilize the difference in affinity with the base material in the process of liquid sample permeating through the column formed by pores as in the chromatograph. A device using a magnetic field or centrifugal force has been devised. Such a method can give excellent separation efficiency by appropriately selecting the conditions, but on the other hand, it takes a certain amount of time to pass through the column, so it is generally inefficient and difficult to process in large quantities. As a result, the lifetime of the column becomes extremely short, so that many columns are required and the column cost is high.

  On the other hand, wetting control of a solid surface is a technical problem located at the boundary between physics and chemistry, and its application range is the most fundamental and important research area in all engineering fields. Conventionally, the wetting of solid surfaces has been studied from both theoretical and experimental viewpoints on the relationship between the wetting characteristics obtained from contact angle measurement and the like and the composition and structure of the solid surface based on Young's equation. However, in recent years, in various engineering fields, the importance of droplet removability, specifically the fall acceleration, has begun to be recognized. However, most of the research so far has been focused on associating measured values of fall acceleration and physical properties on the surface (Non-Patent Documents 1 to 4), and applied dynamic wettability control to liquid separation. There is no example.

Miwa, M., Nakajima, A., Fujishima, A., Hashimoto, K. and Watanabe, T., Langmur. Vol.16, pp5754-5760 (2000) Nakajima, A., Suzuki, S., Kameshima, Y., Yoshida, N., Watanabe, T., and Okada, K., Chem. Lett., 32 [12], 1148-1149 (2003) Yoshida, N., Abe, Y., Shigeta, H., Takami, K., Osaki, K, Watanabe, T., Hashimoto, K., and Nakajima, A., J. Sol-Gel Sci. Tech., 31, 195-199 (2004) Suzuki, S., Kameshima, Y., Nakajima, A., and Okada, K., Surf. Sci., Vol 557 / 1-3 pp L163-L168 (2004)

  An object of the present invention is to provide a droplet separation method that can separate droplets according to the properties of the droplets easily and in a short time. Another object of the present invention is to provide a droplet inspection method that can inspect whether or not a droplet has a predetermined property, the concentration of a solute, and the like in a simple and short time. is there. Furthermore, it is an object of the present invention to provide instruments used in these methods.

  As a result of diligent research, the present inventors have found that when a drop on a slope having a plurality of regions with different drop angles is dropped into a droplet, the drop direction of the droplet changes at the boundary between regions with different drop angles. As a result, the droplet reaches a position different from the case where it falls down on the slope according to gravity, and the arrival point changes depending on properties such as the size of the droplet and the concentration of the solute. I found. Then, the inventors have come up with the idea that it is possible to separate droplets based on their properties using this phenomenon. Furthermore, the inventors have conceived that it is possible to inspect whether or not a droplet has a predetermined property by utilizing this phenomenon, and have reached the present invention.

  That is, the present invention makes use of the fact that droplets are spotted on a slope, the droplet falls on the slope and reaches the bottom of the slope, and the arrival position varies depending on the properties of the droplet. In the method for separating a droplet, the surface of the slope has at least two regions with different drop angles of the droplet, and a straight line extending from the spot to the inside of the slope to the bottom of the slope A method for separating droplets is provided, wherein the at least two regions are arranged so as to pass through the at least two regions having different falling angles. In addition, the present invention drops a certain amount of liquid droplets on the slope, drops on the slope and reaches below the slope, and uses the fact that the arrival position differs depending on the properties of the liquid droplet The surface of the slope has at least two regions with different drop angles of the droplets, and a straight line extending from the spot to the bottom of the slope in the direction immediately below the slope falls. There is provided a method for inspecting a droplet, wherein the at least two regions are arranged so as to pass through the at least two regions having different corners. Furthermore, the present invention provides a droplet separation device that includes a plate having at least two regions having different drop falling angles, and is used for performing the separation method of the present invention. Furthermore, the present invention provides a droplet inspection instrument comprising a plate having at least two regions having different drop falling angles, and used for performing the inspection method of the present invention.

  According to the present invention, there is provided a droplet separation method that can separate droplets according to the properties of the droplets easily and in a short time. The separation method of the present invention can be carried out very simply by spotting a droplet on the slope and collecting the droplet at each position below the slope, and collecting from the spot of the droplet. The time required until is within a few seconds, and can be carried out in a very short time.

  In addition, according to the present invention, there is provided a droplet inspection method capable of inspecting whether a droplet has a predetermined property, the concentration of a solute, and the like in a simple and short time. The inspection method of the present invention can be carried out extremely simply by spotting a droplet on a slope and measuring the position of the droplet falling below the slope. The time required is within a few seconds and can be carried out in a very short time. With this inspection method, beverage quality control, factory drainage management, and the like can be performed very simply and in a short time.

  As described above, the method for separating liquid droplets according to the present invention drops a droplet on a slope, causes the droplet to fall on the slope and reach the bottom of the slope, and reaches according to the nature of the droplet. This is a method of separating droplets by utilizing the fact that the positions are different. The slope used in the method has at least two regions with different drop angles of the droplets. The at least two regions are arranged such that a straight line extending from the spot to the bottom of the slope in the direction directly below the slope passes through the at least two regions having different falling angles. ing.

  The falling angle is an inclination angle when the droplet starts to drop when the droplet is spotted on the flat surface and the surface is inclined. Different rolling angles mean that the liquid repellency is different. When a droplet falls, if the droplet adheres to the surface of the slope (the surface of the slope gets wet), the amount of liquid collected decreases, and the surface of the slope is removed before the next droplet is separated. Since it is necessary to wash and dry, the surface of the slope is preferably liquid repellent with respect to the droplets, and the falling angle of each region is preferably 20 degrees or less. Further, in order to increase the resolution, the difference in the falling angle of each region is preferably 3 degrees or more, and more preferably 5 degrees or more. In addition, the inclination angle of the slope may be an angle larger than the falling angle of the region having the largest falling angle, but if it is too large, the separability is lowered.

In addition, since the droplets used for separation are often aqueous, each region is preferably formed by treatment with at least two types of water repellents having different falling angles. When each region is formed by surface treatment using a water repellent, each region can be formed in an arbitrary pattern, which is advantageous. As the water repellent, those containing fluorine are preferable because they have a large water repellent effect, and fluoroalkylsilanes (those having a large number of fluorines are called perfluoroalkylsilanes) are particularly preferable. The water repellency can be changed by changing the length of the alkyl group in the fluoroalkylsilane or the number of substituted fluorines in the alkyl group. As fluoroalkylsilanes, one hydrogen of silane (SiH ₄ ) is substituted with a long chain alkyl group, and a plurality of hydrogens in the long chain alkyl are substituted with fluorine, and the remaining three hydrogens of the silane are substituted. Are often substituted with a lower alkoxyl group such as a methoxy group or a halogen such as chlorine. Since such fluoroalkylsilane-based water repellents are commercially available, commercially available products can be preferably used. In addition, surface treatment agents such as perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, and perfluoroalkyl phosphates, perfluoroalkyl group-containing oligomers, and various fluorine resins typified by PTFE are also applicable. is there. In addition, alkyl-based water repellents such as octadecyltrimethoxysilane (ODS) that do not contain fluorine can also be used. Since these water repellents are also commercially available, commercially available products can be used. For the water repellent treatment, the immersion method is most excellent in terms of efficiency and cost, but depending on the raw material, a vapor deposition method is also possible.

  As described above, the at least two regions are arranged so that a straight line extending from the spot of the droplet to the lower surface of the inclined surface in the direction directly below the inclined surface passes through the at least two regions having different falling angles. . Here, the “directly below the slope” means the direction of the path in which droplets fall according to gravity when the slope surface is uniform, and when the slope is a flat plane, the slope is the shortest distance. The direction of the path to reach down.

  In order to increase the resolution, in the method of the present invention, it is preferable that the straight line passes through the boundary of the region having different falling angles a plurality of times, and more preferably at least four times.

  The at least two regions having different sliding angles may be three or more types of regions having different sliding angles, but the region is composed of two types of regions having different sliding angles, and the straight line is the two types of regions. Alternating arrangement of the two types of regions so as to pass through the boundary of the region a plurality of times reduces the number of types of water repellent used and makes it easier to form slopes, while still providing sufficient separation It is preferable because the performance is obtained.

  Hereinafter, one example of the separation method of the present invention will be described more specifically with reference to the drawings. 1 and 2 are schematic views for explaining the principle of the method of the present invention. As shown in FIG. 2, in this example, a first water-repellent region 16 (hereinafter simply referred to as “region”) and a second water-repellent treatment formed by two types of water-repellent agents, respectively. Water-repellent regions 18 (hereinafter sometimes simply referred to as “regions”) are alternately arranged in a striped pattern. In FIG. 1, the two types of regions are not shown for clarity. In FIG. 1, reference numeral 10 is a slope, 12 is a droplet, and 14 is a tip of a nozzle for dropping the droplet. The inclined surface 10 is an inclined surface having an inclination angle α. In FIG. 1, the direction indicated as “g sin α direction” and the direction of the white arrow pointing downward in FIG. Direction. In FIG. 1, the “rotation line direction” means a direction in which the striped pattern shown in FIG. The case where the rotation angle Φ is 35 degrees is shown. Note that the optimum rotation angle Φ with the highest resolution depends on the properties of the droplets and the tilt angle. Therefore, preliminary experiments were conducted by changing the rotation angle Φ to find the optimum rotation angle Φ, and then separation was performed. It is preferable to do.

  As is well shown in FIG. 2, a straight line extending to the lower side of the slope in the direction directly below the slope (the direction of the white arrow pointing directly below) passes through the two areas 16 and 18, which have two different falling angles. Thus, the region 16 and the region 18 are arranged. Further, the region 16 and the region 18 are arranged so that the straight line passes through the boundary between the region 16 and the region 18 a plurality of times (four times in the schematic diagram of FIG. 2).

  In the method of the present invention, a droplet is spotted on one point on the upper surface of the slope 10, and the droplet falls on the slope to reach the lower surface of the slope. In this case, the droplet path changes at each boundary between the region 16 and the region 18, and falls down in a zigzag as indicated by a plurality of white arrows bent at right angles in FIG. For this reason, the droplet reaches a position below the slope different from that directly below the slope. The degree of course change at each boundary between the region 16 and the region 18 varies depending on the properties of the droplets, so that the arrival position under the slope varies depending on the properties of the droplets. Therefore, by collecting the droplets that have fallen below the slope at each position, the droplets can be separated based on the properties of the droplets. Here, it goes without saying that “separating droplets” does not mean that a single droplet is separated, but by applying a plurality of droplets to the above method, each droplet is brought into its properties. It means to separate based on.

  Here, as the properties of the droplet, the size of the droplet, the type of solvent constituting the droplet, the type and concentration of one or more solutes in the droplet, the temperature of the droplet, and the surface tension of the droplet Etc. Under the slope of FIG. 1, droplets 20 of different sizes are schematically drawn, indicating that larger droplets fall in a direction closer to the direction directly below the slope.

  If the size of the droplet to be spotted is made constant, the droplet can be separated depending on properties other than the size of the droplet, that is, the type of solvent constituting the droplet, the concentration of one or more solutes in the droplet Can be separated. Further, when the solvent is the same (for example, in the case of an aqueous solution), the droplets can be separated based on the kind and concentration of the solute. The droplet size to be spotted is not particularly limited, but is usually about 5 mg to 45 mg, preferably about 8 mg to 35 mg.

  Droplet collection under the slope can be performed, for example, every several millimeters in the horizontal direction under the slope, whereby droplets having different properties can be separated (fractionated).

  In addition, the pattern of the area | region from which a fall angle differs is not limited to a simple equal width striped pattern as shown in FIG. 2, The thing of a various pattern is employable. Examples of these are shown in FIGS. The pattern shown in FIG. 3 is a striped pattern similar to FIG. 2, but the width of the stripe increases toward the lower side of the slope. The pattern shown in FIG. 4 is obtained by forming each region radially from the spotting position. In the pattern shown in FIG. 5, one region is an elongated right triangle, a plurality of the right triangles are arranged in the slope direction, and the other region is used as the background. In short, the pattern is basically arranged such that the straight line extending from the spot to the bottom of the slope in the downward direction of the slope passes through the at least two areas having different falling angles. What is necessary is just to be arrange | positioned so that this straight line may pass through the boundary of each area | region several times, and it is not limited to the above-mentioned pattern or a pattern similar to them. In the case of various patterns as well, as in the case of the above-mentioned uniform width stripe pattern, it is preferable to perform separation after finding the optimum rotation angle Φ in advance through preliminary experiments.

  According to the separation method of the present invention, droplets having different properties can be separated and recovered based on the properties. Therefore, multiple different types of liquid samples are grouped together with the same properties, or a single liquid with a non-uniform composition (for example, a liquid having a gradient in solute concentration) And so on.

  The same principle as the separation method described above can be applied to the droplet inspection. In other words, if the amount of droplets that land on the slope is constant, the arrival position of the droplets changes based on the composition of the droplets. It can be checked whether or not it has a predetermined composition. For example, in the beverage quality inspection, it is possible to inspect whether or not a predetermined amount of a certain solute (for example, alcohol in alcoholic beverages) is included. Similarly, it is possible to inspect whether or not the concentration of harmful substances in the effluent from the factory is below a predetermined value. Furthermore, when it is known that the solvent is the same and only the concentration of one solute is changed, the concentration of the solute can be inspected (that is, the concentration is measured) by the above method. This is because, for example, a plurality of standard solutions with known concentrations are prepared, the arrival positions for each are examined, the relationship between the concentration and the arrival position is drawn on a calibration curve, and a sample droplet with an unknown concentration is spotted. By applying the reaching position to the calibration curve, it is possible to measure the concentration of the solute in an unknown sample. In addition, since the inspection method of the present invention is performed based on the same principle as the separation method of the present invention described above, the explanations about the separation method of the present invention described above also apply as they are to the inspection method of the present invention ( However, in the inspection method, the amount of droplets to be deposited is constant, and there is no need to collect the droplets under the slope).

  Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited to the following examples.

  Perfluoroalkylsilane (FAS-17) (with a water falling angle of 15 degrees) was coated on the glass surface by CVD under conditions of 150 ° C for 1 hour, and line and space widths of 500 µm each for line and space. The mask was applied and Xe vacuum ultraviolet light was irradiated. The obtained surface was washed with toluene and acetone and immediately subjected to a CVD treatment with octadecyltrimethoxysilane (ODS) (with a water falling angle of 9 degrees) under the same conditions. This surface was tilted to 35 degrees (angle α in FIG. 1), and an experiment was conducted to drop water drops of various sizes by changing the rotation angle (angle Φ in FIG. 1). As a result, on the surface rotated 35 degrees, when a water drop falls, a behavior that moves zigzag laterally on the receding contact angle side (the back end point with the solid) is seen (Fig. 2), 30 mg water drop and 25 mg water drop In the case of water droplets, when the distance from the spotting position to the position directly below the surface was 80 mm, it was shifted 8 mm laterally.

Comparative Example 1
The same operation as in Example 1 was performed on a slope similarly coated with only perfluoroalkylsilane or octadecyltrimethoxysilane (ODS). As a result, each water droplet always landed at the same place, and separation based on the size of the water droplet was not performed.

  An experiment using a mixed solution of water and dioxane was performed on the same surface as in Example 1. A mixed solution in which 0.5 ml to 5 ml of dioxane was added to 10 ml of water was prepared, and a drop experiment was conducted with an appropriate amount of 12 μl. As a result, the dropping route of the droplets differed depending on the concentration of dioxane, and it was possible to separate the droplets depending on the dioxane concentration in the liquid. That is, as the concentration of dioxane was higher, the liquid was deposited at a position farther away from directly below.

Comparative Example 2
The same operation as in Example 2 was performed using a slope in which only perfluoroalkylsilane or octadecyltrimethoxysilane (ODS) was similarly coated. As a result, when the amount of droplets was the same, each droplet always landed at the same location, and separation based on dioxane concentration was not performed.

  In the same manner as in Example 1, experiments were conducted using sake, shochu shochu, awamori and whiskey. However, the rotation angle Φ was 15 °. The results are shown in FIG. As shown in FIG. 6, in shochu and whiskey with high alcohol concentration, the liquid arrives at a position far from the bottom, then awamori, then sake, and the liquid is separated at a distance from the bottom. did. Thereby, it was confirmed by the method of this invention that the test | inspection (test | inspection of alcohol concentration etc.) of a drink is possible.

It is a schematic diagram for demonstrating the principle of the method of this invention. It is a figure which shows typically the slope used in the Example. It is a figure which shows an example of the arrangement | positioning pattern of two types of area | regions from which the fall angle differs on the slope used for the method of this invention. It is a figure which shows another example of the arrangement | positioning pattern of two types of area | regions where the fall angles differ on the slope used for the method of this invention. It is a figure which shows another example of the arrangement pattern of two types of area | regions where the fall angles differ on the slope used for the method of this invention. It is a continuous photograph which shows the mode of the fall of the droplet of alcoholic beverages by the method of this invention performed in the Example.

Explanation of symbols

10 slope 12 droplet 14 nozzle tip 16 first water repellent area 18 second water repellent area 20 droplet

Claims (14)

  A method of spotting a droplet on a slope, causing the droplet to fall on the slope to reach the bottom of the slope, and separating the droplet by utilizing the fact that the arrival position differs depending on the nature of the droplet The surface of the slope has at least two regions with different drop angles of the droplets, and straight lines extending from the landing point to the lower slope in the slope are different in the drop angle. A method for separating droplets, wherein the at least two regions are arranged so as to pass through at least two regions, and the droplets are collected at each position under the slope.   The method according to claim 1, wherein the straight line passes a boundary of the region having different falling angles a plurality of times.   The at least two regions having different sliding angles are composed of two types of regions having different sliding angles, and the two types of regions are alternately arranged so that the straight line passes through the boundary between the two types of regions a plurality of times. The method according to claim 2.   The method according to claim 2 or 3, wherein the straight line passes through a boundary between regions having different falling angles at least four times.   The said at least 2 area | region is formed by processing the surface of the said slope with at least 2 types of water repellents from which a falling angle differs, respectively. Method.   6. The method according to any one of claims 1 to 5, wherein a certain amount of droplets is spotted.   It is a method of inspecting a droplet by spotting a certain amount of droplet on the slope, falling on the slope and reaching under the slope, and using the fact that the arrival position differs depending on the nature of the droplet. The surface of the slope has at least two regions with different drop angles of the droplets, and a straight line extending from the spot to the bottom of the slope in the direction immediately below the slope has the at least two different drop angles. A method for inspecting a droplet, wherein the at least two regions are arranged so as to pass through the regions.   The method according to claim 7, wherein the straight line passes through a boundary between the regions having different falling angles.   The at least two regions having different sliding angles are composed of two types of regions having different sliding angles, and the two types of regions are alternately arranged so that the straight line passes through the boundary between the two types of regions a plurality of times. The method according to claim 8.   The method according to claim 8 or 9, wherein the straight line passes through a boundary between the regions having different falling angles at least four times.   The said at least 2 area | region is formed by processing the surface of the said slope with at least 2 types of water repellents from which a falling angle differs, respectively. Method.   The method according to any one of claims 7 to 11, wherein the inspection method is for checking whether or not a concentration of a solute in the droplet is within a predetermined range.   7. A droplet separation device comprising a plate having at least two regions with different drop falling angles, and used for carrying out the method according to claim 1. 13. A droplet inspection instrument comprising a plate having at least two regions with different drop falling angles, and used for performing the method according to claim 7.

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