JP2020054983A - Liquid droplet generating method and liquid droplet generating device - Google Patents

Abstract

To provide a liquid droplet generating method that can form a liquid droplet in a desired position, and to provide a liquid droplet generating device.SOLUTION: A liquid droplet generating method includes: holding liquid between a first end surface of a first member and a second end surface of a second member; and breaking the liquid so as to form a liquid droplet in a midpoint of a line segment formed by connecting a geometric center of a first area encircled by a first contact line of the liquid coming into contact with the first end surface to a geometric center of a second area encircled by a second contact line of the liquid coming into contact with the second end surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a droplet generation method and a droplet generation device.

  Conventionally, various techniques for generating minute droplets have been proposed. For example, Patent Literature 1 discloses a technique of generating a minute liquid column by periodically dividing a liquid column by applying periodic vibration to a liquid column ejected from a nozzle.

International Publication WO2016 / 170951

  However, in the past, there has been no effective proposal for forming droplets at desired positions.

  Then, an object of the present invention is to provide a droplet generation method and a droplet generation device which can form a droplet at a desired position.

A droplet generation method according to one embodiment of the present invention,
Holding a liquid between the first end surface of the first member and the second end surface of the second member;
A geometric center of a first region surrounded by a first contact line of the liquid contacting the first end surface is connected to a geometric center of a second region surrounded by a second contact line of the liquid contacting the second end surface. The liquid is broken so that a droplet is formed at the midpoint of the line segment.

In the droplet generation method,
The first region and the second region may have the same shape.

In the droplet generation method,
The first end face and the second end face have the same shape,
The first region is the entire region of the first end face,
The second region may be the entire region of the second end surface.

In the droplet generation method,
The third area on the first end face, which has better wettability than other areas on the first end face, and the fourth area on the second end face, which has better wettability than other areas on the second end face, are the same. Shape
The first region is the same as the third region,
The second area may be the same as the fourth area.

In the droplet generation method,
A first central axis of the first region passing through the geometric center of the first region and orthogonal to the first end surface is a second central axis of the second region passing through the geometric center of the second region and orthogonal to the second end surface. It may coincide with the central axis.

In the droplet generation method,
By moving the first member and / or the second member such that the first contact line does not move on the first end surface and the second contact line does not move on the second end surface. The liquid may be broken.

In the droplet generation method,
The liquid may be broken by moving the first member and / or the second member such that the first end surface and the second end surface are separated from each other.

In the droplet generation method,
Both the first member and the second member may be moved so that the midpoint does not move.

In the droplet generation method,
The first member and the second member may be columnar bodies having the same shape.

In the droplet generation method,
The liquid may be broken in a state where the midpoint coincides with the capturing position of the capturing unit.

In the droplet generation method,
Breaking the liquid in a state where the midpoint is coincident between the focal point of the laser beam, the node of the sound pressure of the ultrasonic sound field, or the electrode for applying a voltage to the liquid, as the capturing position of the capturing means. May be.

A droplet generation device according to one embodiment of the present invention,
A first member having a first end face;
A second member having a second end face capable of holding liquid between the first end face;
A geometric center of a first region surrounded by a first contact line of the liquid contacting the first end surface is connected to a geometric center of a second region surrounded by a second contact line of the liquid contacting the second end surface. A breaking portion for breaking the liquid held between the first end face and the second end face so that a droplet is formed at the midpoint of the line segment.

  According to the present invention, a droplet can be formed at a desired position.

FIG. 1 is a diagram illustrating a droplet generation device according to a first embodiment. FIG. 4 is a diagram illustrating a liquid supply step in an operation example of the droplet generation device according to the first embodiment. FIG. 4 is a diagram illustrating a liquid holding step in an operation example of the droplet generation device according to the first embodiment. FIG. 4 is a diagram illustrating a movement process of a first member and a second member in an operation example of the droplet generation device according to the first embodiment. FIG. 4 is a diagram illustrating a liquid breaking step in an operation example of the droplet generation device according to the first embodiment. FIG. 11 is a diagram illustrating a moving process of a second member in an operation example of the droplet generation device according to the second embodiment. It is a figure showing a droplet generation device by a 3rd embodiment. FIG. 14 is a diagram illustrating a liquid holding process in an operation example of the droplet generation device according to the fourth embodiment. It is a figure showing a movement process of the 1st member and the 2nd member in the example of operation of the droplet generation device by a 4th embodiment. FIG. 13 is a diagram illustrating a liquid breaking step in an operation example of the droplet generation device according to the fourth embodiment. It is a figure showing a droplet generation device by a 5th embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings attached to this specification, the scale and the size ratio in the vertical and horizontal directions may be appropriately changed and exaggerated for convenience of understanding of the drawings.

  Further, as used herein, for specifying shapes and geometric conditions and their degrees, for example, terms such as "orthogonal" and "identical" have similar functions without being bound by strict meanings. It should be interpreted to include the expected range.

  Further, as to the terms used in this specification for specifying the degree of wettability of the member surface, for example, terms such as “hydrophilic” and “hydrophobic”, it is assumed that the liquid is “water”. However, the liquid is not limited to water but may be oil or other substances. The term “hydrophilic” means that the liquid is easily wetted, and the term “hydrophobic” means that the liquid is hardly wetted.

(First embodiment)
FIG. 1 is a diagram illustrating a droplet generation device 1 according to the first embodiment. The droplet generation device 1 includes a first member 2, a second member 3, and a break portion 4.

  The first member 2 has a first end face 21. In the example of FIG. 1, the first member 2 is a columnar body having a columnar shape, and the first end face 21 is a circular surface provided at one end of the columnar body. The entire surface of the first end face 21 has hydrophilicity. In order to make the entire surface of the first end face 21 hydrophilic, for example, the entire first member 2 may be formed of a hydrophilic material such as stainless steel, or the first member 2 other than the first end face 21 may be formed. May be formed of a hydrophobic material, and only the first end face 21 may be formed of a hydrophilic material by coating or the like.

  The second member 3 has a second end surface 31 that can hold the cross-linking liquid LIB between the second member 3 and the first end surface 21. The crosslinked liquid LIB contains, for example, water as a main component. In the example of FIG. 1, the second member 3 is a columnar body having a columnar shape, and the second end surface 31 is a circular surface provided at one end of the columnar body on the first end surface 21 side. That is, the second member 3 is a columnar body having the same shape as the first member 2. The entire surface of the second end surface 31 has hydrophilicity. In order to make the entire surface of the second end face 31 hydrophilic, for example, the entire second member 3 may be formed of a hydrophilic material such as stainless steel, or the second member 3 other than the second end face 31 may be formed. May be formed of a hydrophobic material, and only the second end face 31 may be formed of a hydrophilic material by coating or the like.

  In the break portion 4, a droplet is formed at the midpoint P of a line segment L connecting the geometric center C1 of the first area A1 of the first end face 21 and the geometric center C2 of the second area A2 of the second end face 31. Thus, the cross-linking liquid LIB held between the first end face 21 and the second end face 31 is broken.

  Here, the first area A1 is an area on the first end face 21 surrounded by the first contact line CL1 of the cross-linking liquid LIB in contact with the first end face 21. The second area A2 is an area on the second end face 31 surrounded by the second contact line CL2 of the cross-linking liquid LIB in contact with the second end face 31.

  In the example of FIG. 1, the fractured portion 4 holds both the first member 2 and the second member 3 in directions opposite to each other as indicated by arrows in FIG. 1 such that the first end surface 21 and the second end surface 31 are separated from each other. It is an actuator that moves.

  Since a droplet is formed at the midpoint P, the first area A1 and the second area A2 have the same shape. More specifically, in the example of FIG. 1, the first end face 21 and the second end face 31 have the same shape, the first area A1 is the entire area of the first end face 21, and the second area A2 is the second area A2. This is the entire area of the end face 31. In the present embodiment, the first end face 21 and the second end face 31 are circular, but may have another shape (for example, an elliptical shape or a polygonal shape).

  In order to form a droplet at the midpoint P with higher positional accuracy, the first central axis of the first area A1 that passes through the geometric center C1 of the first area A1 and is orthogonal to the first end face 21 is the geometric axis of the second area A2. The second region A2 passes through the center C2 and is orthogonal to the second end surface 31 and coincides with the second central axis. In the example of FIG. 1, the first central axis and the second central axis coincide with the line segment L.

  Further, in order to form a droplet at the midpoint P with higher positional accuracy, the break portion 4 is configured such that the first contact line CL1 does not move on the first end face 21 and the second contact line CL2 is moved to the second end face. By moving the first member 2 and the second member 3 so as not to move on 31, the bridging liquid LIB is broken. For example, the breaking portion 4 moves the first member 2 and the second member 3 along the central axis direction, so that the first contact line CL1 does not move on the first end surface 21 and the second contact line CL1 does not move. CL2 is prevented from moving on the second end surface 31.

  Next, an operation example of the droplet generation device 1 of FIG. 1 will be described. FIG. 2 is a diagram illustrating a supply process of the liquid LI in the operation example of the droplet generation device 1 according to the first embodiment.

  First, as shown in FIG. 2, the liquid LI is supplied between the first end face 21 and the second end face 31 by the liquid supply device 6. The liquid supply device 6 is, for example, a micropipette and a driving device for the micropipette. The supply of the liquid LI is performed, for example, in a state where the first member 2 and the second member 3 are separated from each other in the central axis direction of the end surfaces 21 and 31 by the break portion 4. This is performed so that the liquid LI adheres to one side.

  FIG. 3 is a diagram illustrating a holding process of the crosslinked liquid LIB in an operation example of the droplet generation device 1 according to the first embodiment. After the liquid LI is supplied between the first end face 21 and the second end face 31, the first end face 21 and the second end face 31 are aligned by the break 4 so that the center axes of the first end face 21 and the second end face 31 are aligned. The first member 2 and the second member 3 are moved so that the second end surface 31 approaches. Then, when the first member 2 and the second member 3 move to positions where the liquid LI contacts both the first end surface 21 and the second end surface 31, as shown in FIG. The liquid LI spreads over the entire surface of the end face 31, and the crosslinked liquid LIB is held between the first end face 21 and the second end face 31. That is, a liquid bridge is formed between the first end face 21 and the second end face 31.

  At this time, since the cross-linking liquid LIB wets and spreads over the entire surface of the first end face 21, the first contact line CL1 of the cross-linking liquid LIB contacting the first end face 21 coincides with the outer peripheral end of the first end face 21. . That is, the first area A <b> 1 of the first end face 21 surrounded by the first contact line CL <b> 1 coincides with the entire area of the first end face 21. In addition, since the cross-linking liquid LIB wets and spreads over the entire surface of the second end face 31, the second contact line CL2 of the cross-linking liquid LIB contacting the second end face 31 coincides with the outer peripheral end of the second end face 31. That is, the second area A2 of the second end face 31 surrounded by the second contact line CL2 coincides with the entire area of the second end face 31.

  At this time, as shown in FIG. 3, the cross-sectional area of the cross-linked liquid LIB orthogonal to the central axis direction of the end faces 21 and 31 is the largest at the positions of the first end face 21 and the second end face 31, and It is minimum at the position of P.

  FIG. 4 is a diagram illustrating a moving process of the first member 2 and the second member 3 in the operation example of the droplet generation device 1 according to the first embodiment.

  After holding the cross-linking liquid LIB between the first end face 21 and the second end face 31, the first member is separated from the first end face 21 and the second end face 31 by the break 4 as shown in FIG. The second and second members 3 are moved along the center axis direction of the first end face 21 and the second end face 31. At this time, the breaking portion 4 moves, for example, the first member 2 and the second member 3 at the same speed. In this case, the position of the midpoint P does not change in the moving process of the first member 2 and the second member 3, and remains at the position where the droplet D is to be formed.

  As the first member 2 and the second member 3 move, the bridging liquid LIB held between the first end face 21 and the second end face 31 moves in the central axis direction of the first end face 21 and the second end face 31. Stretched. At this time, the first contact line CL1 of the cross-linking liquid LIB is pinned to the outer peripheral end of the first end face 21 and does not move, and the second contact line CL2 of the cross-linking liquid LIB is the outer peripheral end of the second end face 31. Do not move because it is pinned to. That is, the cross-sectional area of the cross-linking liquid LIB orthogonal to the center axis direction of the end faces 21 and 31 does not change at the positions of the first end face 21 and the second end face 31 and decreases at other positions.

  FIG. 5 is a diagram illustrating a step of breaking the cross-linking liquid LIB in an operation example of the droplet generation device 1 according to the first embodiment.

  When the distance between the first end face 21 and the second end face 31 reaches a predetermined distance by moving the first member 2 and the second member 3 in opposite directions, the distance between the first end face 21 and the second end face 31 is increased. (Cross-link break) of the cross-linking liquid LIB held in the cross section occurs.

  As shown in FIG. 5, when the cross-linking liquid LIB breaks, a droplet D is formed at the midpoint P. In addition, in the examples of FIGS. 3 to 5, the first member 2 and the second member 3 are separated from each other with the center axis of the first end face 21 and the center axis of the second end face 31 aligned with each other. The first member 2 and the second member 3 may be separated from each other in a state where the center axis of the first end face 21 and the center axis of the second end face 31 are shifted.

  As described above, according to the first embodiment, the droplet D is formed at a desired position by breaking the cross-linking liquid LIB so that the droplet D is formed at the intended midpoint P. be able to.

  Further, according to the first embodiment, a simple method is achieved by holding the bridging liquid LIB between the entire area of the first end face 21 and the entire area of the second end face 31 having the same shape as the first end face 21. Thus, the droplet D can be formed at the midpoint P with high positional accuracy.

  Further, according to the first embodiment, by making the first central axis of the first end face 21 coincide with the second central axis of the second end face 31, the droplet D is positioned at the midpoint P with higher positional accuracy. Can be formed.

  According to the first embodiment, the droplet D is formed at the middle point P with higher positional accuracy by breaking the cross-linking liquid LIB without moving the first contact line CL1 and the second contact line CL2. can do.

  Further, according to the first embodiment, both the first member 2 and the second member 3 are moved in a direction in which the first end face 21 and the second end face 31 are separated so that the midpoint P does not move. The droplet D can be formed at the midpoint P with higher positional accuracy. Further, the volume of the droplet D can be easily controlled.

(Second embodiment)
Next, a second embodiment will be described. The second embodiment is different from the first embodiment in that only one of the first member 2 and the second member 3 is moved in the moving step. FIG. 6 is a diagram illustrating a moving process of the second member 3 in an operation example of the droplet generation device 1 according to the second embodiment.

  In the first embodiment, both the first member 2 and the second member 3 are moved so that the midpoint P does not move. On the other hand, in the second embodiment, the breaking portion 4 extends the bridging liquid LIB held between the first end face 21 and the second end face 31 by moving only the second member 3. The midpoint P moves in the moving direction of the second member 3 with the stretching of the crosslinking liquid LIB.

  Then, similarly to the first embodiment, when the distance between the first end face 21 and the second end face 31 reaches a predetermined distance, the crosslinking liquid held between the first end face 21 and the second end face 31 The LIB breaks and a droplet D is formed at the midpoint P.

  According to the second embodiment, by moving only the second member 3, the structure of the break portion 4 (that is, the actuator) is reduced as compared with the case where both the first member 2 and the second member 3 are moved. It can be simplified.

(Third embodiment)
Next, a third embodiment in which the cross-linking liquid LIB is held between the hydrophilic region of the first end surface 21 and the hydrophilic region of the second end surface 31 will be described. FIG. 7 is a diagram illustrating a droplet generation device 1 according to the third embodiment. In the first embodiment, the cross-linking liquid LIB is held between the entire first end face 21 and the entire second end face 31. On the other hand, in the third embodiment, the cross-linking liquid LIB is held between the hydrophilic area on the first end face 21 and the hydrophilic area on the second end face 31.

  Specifically, the first end face 21 has a hydrophilic third region A3. In the example of FIG. 7, the third area A3 is a circular area within a predetermined range on the center side of the first end face 21. The first end face 21 outside the third area A3 has hydrophobicity. The third region A3 can be formed, for example, by partially coating the first end face 21 of the first member 2 formed of a hydrophobic material with a hydrophilic material.

  The second end face 31 has a hydrophilic fourth region A4. In the example of FIG. 7, the fourth area A4 is a circular area in a predetermined range on the center side of the second end face 31. The second end face 31 outside the fourth area A4 has hydrophobicity. The fourth region A4 can be formed, for example, by partially coating the second end face 31 of the second member 3 formed of a hydrophobic material with a hydrophilic material.

  The third area A3 and the fourth area A4 have the same shape. In the present embodiment, the third region A3 and the fourth region A4 are circular, but may have another shape (for example, an elliptical shape or a polygonal shape).

  In the third embodiment, the first member 2 and the first member 2 are arranged such that the first end face 21 and the second end face 31 are separated from each other in a state where the cross-linking liquid LIB is held between the third area A3 and the fourth area A4. When the distance between the first end face 21 and the second end face 31 reaches a predetermined distance by moving the two members 3, the cross-linking liquid LIB held between the third area A3 and the fourth area A4. Is broken to form a droplet D at the midpoint P.

  According to the third embodiment, the hydrophilic third region A3 is provided on the first end surface 21, the hydrophilic fourth region A4 is provided on the second end surface 31, and the third region A3 and the fourth region A4 are provided. By breaking the cross-linking liquid LIB held between the first end face 21 and the second end face 31, the droplet D is formed at a desired position with high positional accuracy while relaxing the restrictions on the shape and size of the first end face 21 and the second end face 31. be able to.

(Fourth embodiment)
Next, a description will be given of a fourth embodiment in which the cross-linking liquid LIB is broken while the midpoint P is set to the focal point of the laser beam. FIG. 8 is a diagram illustrating a step of holding the crosslinked liquid LIB in an operation example of the droplet generation device 1 according to the fourth embodiment. FIG. 9 is a diagram illustrating a moving process of the first member 2 and the second member 3 in an operation example of the droplet generation device 1 according to the fourth embodiment. FIG. 10 is a diagram illustrating a step of breaking the cross-linking liquid LIB in an operation example of the droplet generation device 1 according to the fourth embodiment.

  As illustrated in FIGS. 8 to 10, the droplet generation device 1 according to the fourth embodiment further includes a laser irradiation device 6 that irradiates a laser beam La in addition to the configuration of the first embodiment.

  As shown in FIG. 8, the broken portion 4 is bridged between the first end face 21 and the second end face 31 in a state where the midpoint P is coincident with the focal point of the laser beam La emitted from the laser irradiation device 6. Hold the liquid LIB.

  Next, as shown in FIG. 9, the first member 2 and the first member 2 are separated from each other so that the first end face 21 and the second end face 31 are separated from each other in a state where the midpoint P is coincident with the focal point of the laser beam La. The second member 3 is moved in the opposite direction.

  Then, as shown in FIG. 10, when the distance between the first end face 21 and the second end face 31 reaches a predetermined distance, the cross-linking liquid LIB is moved in a state where the midpoint P coincides with the focal point of the laser light La. The droplet D is broken and a droplet D is formed at the midpoint P. The droplet D formed at the midpoint P is held by the laser beam La.

  According to the fourth embodiment, by setting the focal point of the laser beam La to coincide with the midpoint P, the crosslinked liquid LIB formed at the midpoint P can be stably held at the midpoint P by the laser beam La. .

  Further, according to the fourth embodiment, the conventional optical tweezer method, or the acoustic trap method of capturing a droplet using a sound field or an electrostatic force instead of a laser beam, or the capture of a droplet by an electrostatic floating method is used. In comparison, droplets can be efficiently captured with high accuracy. In the fourth embodiment, the droplet D is held by breaking the cross-linking liquid LIB in a state where the midpoint P is made coincident with the focal point of the laser beam La as the capturing position of the capturing unit. The present invention is not limited to such an embodiment. For example, the droplet D may be held using a method other than the optical tweezer method such as an acoustic trap method or an electrostatic floating method. When the acoustic trapping method is used, the droplet D is held by breaking the cross-linking liquid LIB in a state where the midpoint P matches the node of the sound pressure of the ultrasonic sound field as the capturing position of the capturing means. When the electrostatic floating method is used, the droplet D is held by breaking the cross-linking liquid LIB in a state where the midpoint P is set between the electrodes for applying a voltage to the cross-linking liquid LIB as the capturing position of the capturing unit. . In the electrostatic floating method, by controlling the voltage applied between the electrodes, the charged droplet D can be floated and held between the electrodes.

(Fifth embodiment)
Next, a fifth embodiment in which the first member 2 and the second member 3 are plate-shaped bodies will be described. FIG. 11 is a diagram illustrating a droplet generation device 1 according to the fifth embodiment. In the first embodiment, the first member 2 and the second member 3 are columnar bodies. On the other hand, the first member 2 and the second member 3 in the fifth embodiment are plate-like bodies.

  Similarly to FIG. 7, a hydrophilic third region A3 is provided on the first end surface 21, and a hydrophilic fourth region A4 is provided on the second end surface 31.

  According to the fifth embodiment, it is possible to appropriately form the droplet D at the midpoint P while relaxing the restrictions on the shape and size of the first member 2 and the second member 3.

  In the above-described embodiment, the actuator that moves the first member 2 and the second member 3 is illustrated as the break portion 4. The break portion 4 is not limited to the actuator, and may be, for example, a heater that heats the first end face 21 and the second end face 31. Alternatively, the break portion 4 may be a vibrator that applies vibration to the first end face 21 and the second end face 31. Even in these cases, it is possible to form the droplet D at the midpoint P by breaking the crosslinked liquid LIB by evaporating or vibrating it.

  The above-described embodiment is merely an example, and does not limit the scope of the invention. Various changes can be made to the above-described embodiment without departing from the spirit of the invention. Modified embodiments are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Droplet generation apparatus 2 1st member 21 1st end surface 3 2nd member 31 2nd end surface 4 Breaking part

Claims (12)

Holding a liquid between the first end surface of the first member and the second end surface of the second member;
A geometric center of a first region surrounded by a first contact line of the liquid contacting the first end surface is connected to a geometric center of a second region surrounded by a second contact line of the liquid contacting the second end surface. A droplet generation method for breaking the liquid such that the droplet is formed at the midpoint of the line segment.   The method according to claim 1, wherein the first region and the second region have the same shape. The first end face and the second end face have the same shape,
The first region is the entire region of the first end face,
The method according to claim 2, wherein the second area is an entire area of the second end surface. The third area of the first end face having better wettability than other areas of the first end face is the same as the fourth area of the second end face having better wettability than other areas of the second end face. Shape
The first region is the same as the third region,
The method according to claim 2, wherein the second area is the same as the fourth area.   A first central axis of the first region passing through the geometric center of the first region and orthogonal to the first end surface is a second central axis of the second region passing through the geometric center of the second region and orthogonal to the second end surface. The droplet generation method according to any one of claims 2 to 4, wherein the droplet generation method coincides with the central axis.   By moving the first member and / or the second member such that the first contact line does not move on the first end surface and the second contact line does not move on the second end surface. The droplet generation method according to any one of claims 1 to 5, wherein the liquid is broken.   The liquid according to any one of claims 1 to 6, wherein the liquid is broken by moving the first member and / or the second member such that the first end surface and the second end surface are separated from each other. Droplet generation method.   The droplet generation method according to claim 7, wherein both the first member and the second member are moved so that the midpoint does not move.   The method according to claim 1, wherein the first member and the second member are columnar bodies having the same shape.   The droplet generation method according to claim 1, wherein the liquid is broken in a state where the midpoint coincides with a capturing position of a capturing unit.   Breaking the liquid in a state where the midpoint is matched with the focal point of the laser beam, the node of the sound pressure of the ultrasonic sound field, or between the electrodes for applying a voltage to the liquid, as the capturing position of the capturing means. The method for generating droplets according to claim 10. A first member having a first end face;
A second member having a second end face capable of holding liquid between the first end face;
A geometric center of a first region surrounded by a first contact line of the liquid contacting the first end surface is connected to a geometric center of a second region surrounded by a second contact line of the liquid contacting the second end surface. A droplet generation device comprising: a break portion that breaks a liquid held between the first end surface and the second end surface such that a droplet is formed at a midpoint of a line segment.

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