JP2014202579A - Surface tension measurement apparatus, surface tension measurement method, critical micelle concentration measurement apparatus, and critical micelle concentration measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface tension measurement apparatus configured to easily measure dynamic surface tension by means of a pendant drop method, and a surface tension measurement method, a critical micelle concentration measurement apparatus, and a critical micelle concentration measurement method.SOLUTION: A control apparatus 110 of a surface tension measurement apparatus includes: an initial droplet forming means 113 which causes a discharge device to discharge a liquid sample 2 in a predetermined initial amount of droplet which hangs from a tip of a needle; and a correction droplet forming means 114 which, every time a droplet drops from the tip of the needle, causes a discharge device to discharge the liquid sample in a corrected amount of droplet, the amount being less than the droplet which dropped from the discharge device, which hangs from the tip of the needle. A image processing apparatus 120 includes: a droplet image acquisition means 122 which acquires an image of droplet at multiple points of time; and a surface tension deriving means 123 which derives surface tension for each of the droplet images obtained at multiple points of time.

Description

  The present invention relates to a surface tension measuring device and a surface tension measuring method for measuring the surface tension of a liquid, a critical micelle concentration measuring device for measuring the critical micelle concentration of an amphipathic molecule such as a surfactant by measuring the surface tension, and a criticality measuring device. The present invention relates to a micelle concentration measurement method.

  Conventionally, as a method for measuring the surface tension (interface tension) of a liquid, a hanging drop method (pendant drop method), a Wilhelmy method, a maximum bubble pressure method, and the like are known. Among these, the hanging drop method is a method of suspending a droplet of a liquid sample from a tubular needle tip and obtaining the surface tension from the shape of the suspended droplet (for example, see Patent Document 1). Therefore, according to the hanging drop method, the surface tension can be measured by using a general contact angle measuring device including an ejection device and an imaging device for ejecting a liquid sample from the needle tip, compared with other methods. The hanging drop method is widely used as a method for easily measuring the surface tension. Some existing contact angle measuring devices are provided with a surface tension measuring function by the hanging drop method in advance.

Japanese Patent Laid-Open No. 6-319441

  However, the hanging drop method has a problem that it is difficult to measure a dynamic surface tension, that is, a change with time of the surface tension. For example, in a liquid containing an amphiphilic molecule such as a surfactant, the amphiphilic molecule is attracted to the interface every time a new interface (surface) is generated, and the surface tension is reduced by rearranging the interface. In order to reduce the surface tension, the surface tension decreases until the arrangement of the amphiphilic molecules reaches an equilibrium state, but it is difficult to measure the surface tension that decreases with time in the hanging drop method. there were.

  In other words, the suspended drop method is to obtain the surface tension from the balance between the surface tension and the weight of the droplet, so if the surface tension drops to a value that cannot hold the droplet, the droplet will drop. Therefore, it was impossible to measure a surface tension lower than that. On the other hand, when the droplet is made small so that the droplet does not fall, the surface tension is too much to overcome the weight of the droplet in the initial state where the surface tension is high, and the shape of the droplet becomes substantially spherical. It was difficult to accurately measure the surface tension.

  For this reason, in the measurement of the surface tension of liquids containing surfactants and the measurement of critical micelle concentration (CMC) such as surfactants based on the measurement of surface tension, a dedicated device is conventionally required. The Wilhelmy method and the maximum bubble pressure method are generally used. However, as the application range of surfactants and the like has increased in recent years, a simpler measurement method has been desired.

  In view of such circumstances, the present invention provides a surface tension measuring device, a surface tension measuring method, a critical micelle concentration measuring device, and a critical micelle concentration measuring method capable of easily measuring dynamic surface tension by a hanging drop method. Is to provide.

  (1) The present invention provides a discharge device that discharges a liquid sample from the tip of a tubular needle, an image pickup device that picks up a liquid droplet hanging from the tip of the needle, and a control device that controls the discharge device and the image pickup device. And an image processing device for deriving the surface tension of the liquid sample based on the image of the liquid droplet picked up by the image pickup device, and the control device causes the discharge device to discharge the liquid sample to obtain a predetermined value. A starting droplet forming means for dropping the droplet of the starting liquid amount from the tip of the needle, and each time the droplet drops from the tip of the needle, the liquid sample was discharged to the discharge device and dropped Correction liquid droplet forming means for dropping the liquid droplet having a correction liquid amount smaller than the liquid droplet from the tip of the needle, and the image processing apparatus acquires a liquid droplet image at a plurality of time points. Image acquisition means and acquired Characterized in that it comprises a surface tension deriving means for deriving the surface tension, the each image of the droplet at several time points, a surface tension measuring device.

  (2) The present invention also includes a data processing device that generates temporal change data of the surface tension of the liquid sample based on the surface tension derived by the image processing device, and the data processing device includes: The surface tension measuring device according to (1), further comprising an effective surface tension selecting unit that selects an effective surface tension based on the derived surface tension based on the liquid amount of the droplet.

  (3) The data processing apparatus according to (2), wherein the data processing device further includes time-change data generating means for generating time-change data in which the effective surface tensions are arranged in time series. This is a surface tension measuring device.

  (4) The present invention is also characterized in that the time-change data generating means generates the time-change data by associating an elapsed time from a reference time point for each droplet with the effective surface tension. The surface tension measuring device according to (3).

  (5) The present invention is also characterized in that the control device comprises measurement end means for ending the measurement when the change in the effective surface tension falls within a predetermined range. 4) The surface tension measuring device according to any one of the above.

  (6) The present invention is also characterized in that the correction liquid amount is set to 75 to 99% of the liquid amount of the dropped liquid droplets. This is a surface tension measuring device.

  (7) In the present invention, the control device also includes a falling droplet forming unit that causes the discharge device to discharge the liquid sample until the droplet drops from the tip of the needle, and the falling droplet forming unit is dropped. The surface tension measurement according to any one of (1) to (6), further comprising: a starting liquid amount setting unit that sets the starting liquid amount based on the liquid amount of the liquid droplets. Device.

  (8) The present invention also includes the surface tension measuring device according to any one of (1) to (7) above, and a supply device that supplies the liquid sample containing amphiphilic molecules to the discharge device. The supply device is a critical micelle concentration measurement device configured to supply a plurality of types of liquid samples having different concentrations of the amphiphilic molecules to the discharge device.

  (9) The present invention also measures the surface tension in a surface tension measuring device comprising: a discharge device that discharges a liquid sample from the tip of a tubular needle; and an imaging device that picks up an image of a droplet that hangs down from the tip of the needle. A method of forming a liquid droplet by causing the liquid sample to be ejected by the ejection device to suspend the liquid droplet of a predetermined starting liquid amount from the tip of the needle, and the liquid droplet falling from the tip of the needle Each time the liquid sample is ejected by the ejection device, a correction liquid droplet forming step of dropping the liquid droplet having a smaller correction liquid amount than the liquid droplet dropped from the tip of the needle, and imaging by the imaging device A droplet image acquiring step for acquiring images of the droplets at a plurality of time points, and a surface tension deriving step for deriving a surface tension of the liquid sample for each of the acquired image of the droplets at the plurality of time points. Wherein the bets are surface tension measurement method.

  (10) The present invention also provides a critical micelle using a surface tension measuring device comprising: a discharge device that discharges a liquid sample from the tip of a tubular needle; and an image pickup device that picks up an image of a liquid droplet hanging from the tip of the needle. A concentration measurement method, a concentration setting step for setting a concentration of amphiphilic molecules in the liquid sample, and a surface tension measurement step for measuring a surface tension for the liquid sample having a concentration set in the concentration setting step; The surface tension measuring step includes: a starting droplet forming step of causing the liquid sample to be discharged to the discharge device and dropping the droplet of a predetermined starting liquid amount from the tip of the needle; Each time the liquid droplet falls from the tip, the liquid sample is ejected by the ejection device, and the liquid droplet having a smaller amount of correction liquid than the liquid droplet dropped is dropped from the tip of the needle. A droplet image acquisition step for acquiring images of the droplets at a plurality of time points captured by the imaging device, and a surface for deriving the surface tension of the liquid sample for each of the acquired image of the droplets at the plurality of time points A method for measuring a critical micelle concentration, comprising: a tension derivation step.

  According to the surface tension measuring device and the surface tension measuring method, and the critical micelle concentration measuring device and the critical micelle concentration measuring method according to the present invention, the dynamic surface tension can be easily measured by the hanging drop method. Can have an effect.

1 is a schematic diagram of a surface tension measuring device according to a first embodiment of the present invention. It is the block diagram which showed the main function structures of the computer in 1st Embodiment. It is the schematic which showed the image imaged by (a)-(c) imaging device. (A)-(c) It is the figure which showed an example of the time-dependent change of surface tension. It is the flowchart which showed the measurement procedure of the surface tension by a surface tension measuring apparatus. It is the schematic of the critical micelle concentration measuring apparatus which concerns on the 2nd Embodiment of this invention. It is the block diagram which showed the main function structures of the computer in 2nd Embodiment. It is the schematic which showed the relationship between the density | concentration of an amphiphilic molecule | numerator, and final surface tension with the semilogarithmic graph. It is the flowchart which showed the measurement procedure of the critical micelle density | concentration by a critical micelle density | concentration measuring apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, the surface tension measuring device 1 according to the first embodiment of the present invention will be described. The surface tension measuring device 1 according to the present embodiment measures the time-dependent change in the surface tension of the liquid sample 2, particularly the time-dependent decrease in the surface tension due to a surfactant or the like, using a hanging drop method. The measuring device is also used as a surface tension measuring device. That is, the surface tension measuring device 1 can be configured by utilizing an existing contact angle measuring device, and can also be used as a contact angle measuring device.

  FIG. 1 is a schematic diagram of a surface tension measuring apparatus 1 according to the present embodiment. As shown in the figure, the surface tension measuring device 1 includes a base 10, a stage 20 disposed substantially at the center of the base 10, a discharge device 30 disposed above the stage 20, and a base 10, an imaging device 40 disposed on one end side (right side in the figure), an illumination device 50 disposed on the other end side (left side in the figure) of the base 10, and a tray 60 placed on the stage 20. And a computer 100.

  The base 10 is a member that supports the stage 20, the ejection device 30, the imaging device 40, the illumination device 50, and the like. The base 10 includes a leg portion 12 having a height adjusting mechanism, and can adjust its levelness. Further, a support column 14 that supports the imaging device 40 is provided on the upper portion of the base 10, and an arm 16 that supports the discharge device 30 is provided above the support column 14 so as to protrude above the stage 20. Yes. Further, a cover 18 that covers the entire apparatus can be attached to the upper portion of the base 10 as necessary, and the state of the measurement atmosphere such as temperature and humidity can be kept substantially constant. ing.

  The stage 20 is a so-called XYZ stage provided with a moving mechanism 24, and a solid sample is placed on the placement surface 22 when the contact angle is measured. In the present embodiment, the stage 20 is used as a mounting table for the tray 60. When the surface tension measuring device 1 is configured as a dedicated device, the stage 20 can be omitted.

  The discharge device 30 is disposed at the tip of the arm 18 and discharges the liquid sample 2 whose surface tension is measured downward. The discharge device 30 includes a tubular needle 32 together with a known structure such as a cylinder and a plunger, and is controlled by the computer 100 to discharge a predetermined amount of the liquid sample 2 from the needle tip 32 a that is the tip of the needle 32. The discharged liquid sample 2 forms a droplet 2a due to its own surface tension, and this droplet 2a is suspended (suspended) from the needle tip 32a according to the balance between its own weight and surface tension. It will be maintained or fall away from the needle tip 32a.

  The imaging device 40 is fixed to the column 16 and images the droplet 2a from the side. In the present embodiment, the imaging device 40 is composed of a CCD camera having a magnifying lens system. The imaging device 40 is controlled by the computer 100 to magnify and image the droplet 2 a that hangs down from the needle tip 32 a of the ejection device 30, and transmits image data to the computer 100.

  The illuminating device 50 is disposed so as to face the imaging device 40, and illuminates the droplet 2a from behind when imaging the droplet 2a. The illuminating device 50 includes a light source such as a halogen lamp or an LED, and is configured to emit light toward the droplet 2a.

  The tray 60 receives and accumulates the liquid droplets 2a dropped from the needle tip 32a of the discharge device 30. That is, the tray 60 is for preventing the liquid sample 2 from contaminating the apparatus and the periphery of the apparatus. In place of the tray 60 or together with the tray 60, an absorbent material such as a sponge may be disposed.

  Although not shown, the computer 100 includes a CPU, storage means such as ROM, RAM, hard disk, and flash memory, display means such as a liquid crystal display, and input means such as a keyboard and a mouse. Yes. The computer 100 has a control device 110 that controls the stage 20, the ejection device 30, the imaging device 40, the illumination device 50, and the like as a main functional configuration that operates by executing a program stored in the storage unit, and the imaging device 40. The image processing apparatus 120 that processes the image captured by the image processing apparatus 120 and the data processing apparatus 130 that processes the surface tension derived from the image are provided.

  FIG. 2 is a block diagram illustrating a main functional configuration of the computer 100. As shown in the figure, the control device 110 includes, as a specific functional configuration, a falling droplet forming unit 111, a starting liquid amount setting unit 112, a starting droplet forming unit 113, and a corrected droplet forming unit 114. And an end determination means 115 and a measurement end means 116.

  The falling droplet forming means 111 controls the ejection device 30 before starting the measurement of the surface tension, and ejects the liquid sample 2 until the droplet 2a falls from the needle tip 32a of the ejection device 30. The amount (weight) of the droplet 2a (falling droplet) when dropped is substantially balanced with the initial surface tension (substantially maximum surface tension) of the liquid sample 2. That is, the liquid amount when the droplet 2a is dropped is the upper limit of the liquid amount that can be held by the surface tension of the liquid sample 2, and the falling droplet forming means 111 is for measuring the upper limit of the liquid amount. is there.

  The starting liquid amount setting means 112 is a liquid of the droplet 2a that is first formed in the measurement of the surface tension based on the falling liquid amount that is the liquid amount when the droplet 2a dropped by the falling droplet forming means 111 is dropped. The starting liquid amount, which is the amount, is set. The starting liquid amount setting unit 112 acquires the amount of falling liquid from the control information of the discharge device 30 such as the amount of movement of the plunger or the image obtained by imaging the droplet 2a. And the liquid amount which reduced the acquired fall liquid amount by the predetermined ratio is set as a start liquid amount. The set starting liquid amount is stored in the storage means of the computer 100.

  In the surface tension measurement by the hanging drop method, when the liquid volume of the droplet 2a is too small, the surface tension is too much to overcome the weight of the liquid droplet 2a, making it difficult to accurately measure the surface tension. When there is too much, the droplet 2a will fall by the slight fall of surface tension. Therefore, considering the measurement accuracy and the smooth progress of the measurement, the starting liquid amount is preferably in the range of 75% to 99% of the falling liquid amount, and 85% to 95% of the falling liquid amount. If it is in the range, it is more preferable.

  The start droplet forming means 113 controls the discharge device 30 to discharge the liquid sample 2 of the start liquid amount from the needle tip 32a, and forms the first droplet 2a (start droplet) in the measurement of the surface tension. is there. The droplet 2a of this starting liquid amount falls from the needle tip 32a after the surface tension is lowered until it matches the starting liquid amount. Accordingly, it is possible to measure a change over time from the initial surface tension of the liquid sample 2 to the surface tension balanced with the starting liquid amount, based on the image captured from the formation of the starting liquid droplet 2a to the drop.

  The correction liquid droplet forming means 114 controls the discharge device 30 each time the liquid droplet 2a falls, and discharges the liquid sample 2 of the correction liquid volume that is smaller than the liquid droplet 2a that has dropped, and the next liquid liquid A droplet 2a (corrected droplet) is formed. In this way, by forming the droplet 2a smaller than the dropped droplet 2a, the droplet 2a can be maintained in a suspended state to a surface tension lower than that of the dropped droplet 2a. Can be measured. That is, in the present embodiment, the modified droplet forming means 114 successively forms droplets 2a smaller than the previous droplet 2a, thereby enabling the surface tension to be measured over a wide measurement range. Yes.

  The surface tension of the correction liquid droplet 2a can be measured below the surface tension at the time of dropping the previous droplet 2a (or below the surface tension at a time slightly before the falling if there is a margin). Anything is acceptable. Therefore, similarly to the above-described relationship between the falling liquid amount and the starting liquid amount, the correction liquid amount is in the range of 75% to 99% of the previous liquid amount, which is the liquid amount of the previous droplet 2a. It is more preferable if it is within the range of 85% to 95% of the previous liquid amount. The amount of the correction fluid is measured based on the control information of the ejection device 30 or the image obtained by imaging the droplet 2a and is stored in the storage unit of the computer 100.

  In addition, the droplet 2a of the correction fluid amount falls from the needle tip 32a after the surface tension is lowered until it is balanced with the correction fluid amount. That is, it is possible to measure a change over time from the surface tension when the previous droplet 2a is dropped to the surface tension balanced with the amount of correction fluid based on an image obtained by imaging the droplet 2a with the amount of correction fluid.

  The end determination means 115 determines whether or not the measured surface tension has reached a substantially equilibrium state. The end determination means 115 refers to the time-dependent change data of the surface tension, and the measured surface tension has reached a substantially equilibrium state based on whether or not the change in the surface tension within the predetermined time range is within the predetermined range. It is determined whether or not. The measurement end means 116 performs a predetermined end process to end the measurement. The measurement end unit 116 ends the measurement of the surface tension after performing a predetermined end process such as displaying the measurement result on the display unit or issuing an alarm notifying the end of the measurement.

  The image processing apparatus 120 includes a needle tip position detection unit 121, a droplet image acquisition unit 122, a surface tension derivation unit 123, and a droplet drop determination unit 124 as specific functional configurations. 3A to 3C are schematic diagrams illustrating images captured by the imaging device 40. FIG.

The needle tip position detection unit 121 detects the position of the needle tip 32 a of the ejection device 30 based on the image captured by the imaging device 40. As shown in FIG. 3A, the needle 32 is captured as a silhouette image by being illuminated from behind by the illumination device 50. Therefore, the position of the needle tip 32a can be detected by detecting the boundary between the needle 32 projected as a dark area and the bright background area. The detected position of the needle tip 32a is stored in the storage means of the computer 100 as coordinates in the image by the needle tip position detecting means 121. For example, in the example shown in FIG. 3A, the coordinates (x ₁ , y ₁ ) and (x ₂ , y ₁ ) of both ends of the needle tip 32a are stored.

  The droplet image acquisition unit 122 acquires an image obtained by imaging the droplet 2a in a state of hanging from the needle tip 32a of the ejection device 30 at a predetermined sampling period. The acquired image of the droplet 2a is stored in the storage unit of the computer 100 in association with the imaging time (sampling time).

  The surface tension deriving unit 123 derives the surface tension based on the image acquired by the droplet image acquiring unit 122. As shown in FIG. 3B, the droplet 2a that hangs down from the needle tip 32a is picked up as a silhouette image, so that it is lower than the position of the needle tip 32a detected by the needle tip position detecting means 121. By detecting the boundary between the dark region and the bright region, the contour shape of the droplet 2a can be detected. The surface tension of the liquid sample 2 can be derived from the contour shape of the droplet 2a.

Derivation of surface tension, as shown in FIG. 3 (b), _{d s} calculated from the diameter _{d s} in _{d e} only the upper position from the lowest point of the maximum diameter _{d e,} and droplet 2a droplet 2a / _{d e} method by may be performed, it may be performed by Young-Laplace method for fitting a theoretical curve obtained by solving the Young-Laplace equation contour shape of the droplets 2a. The derived surface tension is stored in the storage unit of the computer 100 in association with the image capturing time. Thus, by deriving the surface tension for each acquired droplet image, the surface tension can be acquired at a predetermined sampling period.

  The droplet drop determination unit 124 determines whether or not the droplet 2a has dropped based on the image captured by the imaging device 40. As shown in FIG. 3C, the droplet drop determining means 124 sets a predetermined range of determination area A below the position of the needle tip 32a in the image captured by the imaging device 40, and this determination is performed. The fall of the droplet 2a is determined depending on whether or not the region A includes a dark region where the droplet 2a is projected.

  As shown in FIG. 3C, the residual liquid 2b may remain on the needle tip 32a after the droplet 2a falls. In such a case, the droplet drop determination unit 124 derives the liquid amount of the residual liquid 2b based on an image obtained by imaging the residual liquid 2b and stores it in the storage unit of the computer 100. Then, the correction liquid droplet forming unit 114 corrects the correction liquid amount that is the liquid amount of the next liquid droplet 2a based on the stored liquid amount of the residual liquid 2b.

  Returning to FIG. 2, the data processing device 130 includes an effective surface tension selection unit 131 and a time-change data generation unit 132 as specific functional configurations. The effective surface tension selection unit 131 selects an effective surface tension from the surface tension derived by the surface tension deriving unit 123 of the image processing apparatus 120 based on the liquid amount of each droplet 2a. That is, the surface tension that is excessively large with respect to the liquid amount of each droplet 2a is excluded from the plurality of surface tensions derived for each droplet 2a, and an appropriate measurement is possible depending on the liquid amount of each droplet 2a. Select the surface tension. Specifically, the effective surface tension selection unit 131 sets a surface tension equal to or less than the surface tension at the time of dropping the previous droplet 2a or less than the surface tension at the time slightly before the dropping based on the correction liquid amount setting. Select as effective surface tension.

  The temporal change data generation means 132 combines the effective surface tensions selected for each droplet 2a by the effective surface tension selection means 131 and generates temporal change data of the surface tension. Specifically, the time-change data generating unit 132 generates time-change data by combining the selected effective surface tension in association with the elapsed time from the reference time for each droplet 2a. That is, the change (decrease) in the surface tension starts when a new interface is formed, that is, when the droplet 2a is formed. For example, the time point when the formation of each droplet 2a is completed is set as the reference time point. By associating the elapsed time from the effective surface tension derived from each droplet 2a with the effective surface tension derived from the different droplets 2a, the temporal change data of the surface tension can be generated simply by arranging in order of elapsed time. Will be.

  The elapsed time from the reference time may be calculated from the imaging time of each image and the time when the droplet 2a is formed, or the imaging time of each image may be calculated in advance from the reference time for each droplet 2a. You may leave it as time. Further, the reference time point is not limited to the time point when the formation of each droplet 2a is completed. For example, the reference time point may be a time point when the discharge of the liquid sample 2 is started, or a predetermined time after the completion of the formation of each droplet 2a. It may be after a lapse of time. In other words, the reference time point may be a time point at which the reference of the temporal change of the surface tension can be uniformly determined for each droplet 2a.

  Further, the data processing device 130 may include a final surface tension acquisition unit that acquires a final surface tension, which is a final surface tension that has reached an equilibrium state, based on the generated temporal change data.

FIGS. 4A to 4C are graphs showing an example of the temporal change in surface tension. As shown in FIG. 4A, the surface tension (γ) of the liquid sample 2 containing an amphiphilic molecule such as a surfactant is changed from the initial surface tension γ ₀ to the time (T ) Gradually decreases, and the arrangement of the amphiphilic molecules becomes an equilibrium state, so that the final surface tension γ _e becomes an approximately equilibrium state. Since the change in the surface tension depends on the concentration of the amphiphilic molecule, the surface tension shows the same change mode regardless of the size of the new interface, that is, the size (liquid amount) of the droplet 2a. Become.

FIG. 4B shows the change in the surface tension of the first droplet 2a (starting droplet). As shown in the figure, in the first droplet 2a, the surface tension gradually decreases from the initial surface tension γ ₀ at the reference time T ₀ (when the first droplet 2a is formed), and at the elapsed time T ₁ . The surface tension γ ₁ is balanced with the starting liquid amount. Immediately thereafter, the droplet 2a falls. Since the amount of the starting liquid is set to an initial surface tension γ ₀ and an amount capable of appropriately deriving the surface tension below this, the effective surface tension range of the first droplet 2 a is from the vicinity of the initial surface tension γ _0. The surface tension is close to γ ₁ that balances the starting liquid amount.

FIG. 4C shows a change in surface tension of the second droplet 2a. As shown in the figure, the surface tension of the second droplet 2a is equal to the initial surface tension γ ₀ at the reference time T ₀ (when the second droplet 2a is formed) as in the case of the first droplet 2a. The surface tension γ ₁ gradually decreases from the time point T1, and becomes the surface tension γ ₁ that balances the starting liquid amount at the elapsed time T ₁ . Thereafter, the surface tension of the second liquid droplet 2a, elapsed time T the amount of liquid ₂ in the second droplet 2a (correction fluid volume) and balances the surface tension gamma _2, and the immediately thereafter, the droplet 2a falls It will be. The amount of correction liquid in the second droplet 2a is set to an amount that can appropriately derive the surface tension γ ₁ that balances with the starting liquid amount and the surface tension below this, so that the effective surface in the second droplet 2a The range of tension is from the vicinity of the surface tension γ _{1 to the} vicinity of the surface tension γ ₂ .

FIG. 4D shows the change in surface tension of the third droplet 2a. As shown in the figure, also in the third droplet 2a, the surface tension gradually decreases from the initial surface tension γ ₀ at the reference time T ₀ (when the third droplet 2a is formed), and the elapsed time T the surface tension gamma ₁ becomes balanced with the starting solution volume in _1, a surface tension gamma ₂ which in the course time T ₂ balances the liquid volume of the second droplet 2a. Thereafter, the surface tension is further reduced in the third droplet 2a, it does not reach the surface tension gamma ₃ surface tension balances the liquid volume of the third droplet 2a (correction fluid volume), higher final A substantially equilibrium state is reached at the surface tension γ _e . The amount of correction liquid in the third droplet 2a is set to an amount capable of appropriately deriving the surface tension γ ₂ that balances the amount of liquid in the second droplet 2a and the surface tension γ below this surface tension γ ₂ . the range of valid surface tension in the droplet 2a becomes to around a surface tension gamma ₃ commensurate with the amount of liquid the third droplet 2a from the vicinity of the surface tension gamma ₂ (correction fluid volume) of. Therefore, the final surface tension γ _e is included in the effective surface tension range of the third droplet 2a.

As described above, since the surface tension γ of the liquid sample 2 changes (decreases) in substantially the same manner even in different droplets 2a, the liquid amount of each droplet 2a is decreased in order, so that the liquid It is possible to cover the range from the initial surface tension γ ₀ to the final surface tension γ _e by shifting the range of the effective surface tension for each droplet 2 a to the lower side. That is, the surface tension γ can be derived with high accuracy over the entire range from the initial surface tension γ ₀ to the final surface tension γ _e based on the image obtained by imaging each droplet 2a. In addition, it is possible to obtain temporal change data from the initial surface tension γ ₀ to the final surface tension γ _e of the surface tension γ of the liquid sample 2 only by connecting the effective surface tensions derived from the respective droplets 2 a.

Thus, in this embodiment, every time the droplet 2a falls, a smaller droplet 2a is formed, and the range of the effective surface tension is appropriately set for each droplet 2a. by associating the elapsed time from the reference time T ₀ per each droplet 2a, the time course of the surface tension gamma, can be obtained over the entire range from the initial surface tension gamma ₀ to the final surface tension gamma _e with high precision It has become. That is, the dynamic surface tension can be measured easily and with high accuracy by the hanging drop method.

  Next, the procedure for measuring the surface tension by the surface tension measuring device 1 of the present embodiment will be described. FIG. 5 is a flowchart showing a procedure for measuring the surface tension by the surface tension measuring device 1. In measuring the surface tension, the liquid sample 2 is enclosed in the ejection device 30 in advance, and the ejection device 30 and the imaging device 40 are disposed at a position where the liquid droplet 2a suspended from the needle tip 32a can be imaged. Keep it.

  In the measurement of the surface tension by the surface tension measuring device 1, first, imaging is started in step S10 (imaging start step). Here, the control device 110 controls the imaging device 40 to start imaging, and adjusts the focus and magnification rate of the imaging device 40 as necessary. Next, in step S11, the position of the needle tip 32a of the discharge device 30 is detected (needle tip position detection step). Here, the needle tip position detection means 121 of the image processing device 120 detects and stores the position of the needle tip 32 a based on the image captured by the imaging device 40.

  Next, in step S12, a droplet 2a to be dropped for measuring the amount of falling liquid is formed (falling droplet forming step). Here, the falling droplet forming means 111 of the control device 110 controls the discharge device 30 to form the droplet 2a and drop it. Next, in step S13, a starting liquid amount is set (starting liquid amount setting step). Here, the starting liquid amount setting means 112 of the control device 110 sets the starting liquid amount based on the measured falling liquid amount. Next, in step S14, the first droplet 2a is formed (start droplet forming step). Here, the start droplet forming means 113 of the control device 110 controls the discharge device 30 to form the droplet 2a of the start liquid amount and is in a state of hanging from the needle tip 32a of the discharge device 30.

  Next, in step S15, an image obtained by imaging the droplet 2a that is suspended from the needle tip 32a is acquired (droplet image acquisition step). Here, the droplet image acquisition means 122 of the image processing device 120 acquires and stores the image of the droplet 2a captured by the imaging device 40 at a predetermined sampling period. Next, in step S16, surface tension is derived based on the image of the droplet 2a (surface tension deriving step). Here, the surface tension deriving unit 123 of the image processing apparatus 120 derives the surface tension based on the image of the droplet 2a acquired in step S15.

  Next, in step S17, an effective surface tension is selected from the derived surface tension (effective surface tension selection step). Here, when the surface tension derived in step S16 is the effective surface tension, the effective surface tension selection unit 131 of the data processing device 130 selects this as the effective surface tension. Next, in step S18, surface tension change data is generated (time change data generation step). Here, the temporal change data generation means 132 of the data processing device 130 adds the effective surface tension selected in step S17 to the temporal change data in association with the elapsed time from the reference time point, so that Generate change data.

  Next, in step S19, it is determined whether or not the surface tension has reached an equilibrium state (end determination step). Here, the end determination unit 115 of the control device 110 refers to the temporal change data of the surface tension and determines whether or not the measured surface tension, that is, the effective surface tension has reached an equilibrium state. If it is determined that the effective surface tension has reached the equilibrium state, the process proceeds to step S20. If it is determined that the effective surface tension has not reached the equilibrium state, the process proceeds to step S21. In step S20, the measurement end unit 116 of the control device 110 performs a predetermined end process to end the measurement (measurement end step).

  In step S21, it is determined whether or not the droplet 2a has dropped from the needle tip 32a (droplet drop determination step). Here, the droplet drop determination unit 124 of the image processing device 120 determines whether or not the droplet 2a has dropped from the needle tip 32a of the ejection device 30 based on the image captured by the imaging device 40. If it is determined that the droplet 2a has been dropped, the process proceeds to step S22, and if it is determined that the droplet 2a has not been dropped, the process returns to step S15. Accordingly, the processes in steps S15 to S18 are repeated until the droplet 2a falls or the effective surface tension reaches equilibrium.

  In step S22, the liquid droplet 2a having the correction liquid amount is formed (correction liquid droplet forming step). Here, the correction liquid droplet forming means 114 of the control device 110 controls the ejection device 30 to form the liquid droplet 2a having the correction liquid amount, and is suspended from the needle tip 32a of the ejection device 30. After step S22, the process returns to step S15, and the processes of steps S15 to S18 are repeated until the droplet 2a having the correction fluid amount falls or the effective surface tension reaches equilibrium.

  With the above procedure, the change with time of the surface tension of the liquid sample 2 is measured. When the initial surface tension of the liquid sample 2 is known in advance, step S12 is omitted, and the starting liquid amount is set in step S13 based on the initial surface tension or the liquid amount input by the user. It may be. Further, the selection of the effective surface tension in step S17 and the generation of the time-dependent change data in step S18 may be performed together immediately before the end process in step S20. In step S19, it is determined that the surface tension has reached an equilibrium state when the droplet 2a does not fall after a predetermined time has elapsed, the surface tension is derived in step S16, and the effective surface tension in step S17. And the generation of the time-varying data in step S18 may be performed together immediately before the end process in step S20.

  Next, the critical micelle concentration measuring apparatus 3 according to the second embodiment of the present invention will be described. The critical micelle concentration measuring apparatus 3 of the present embodiment measures the dynamic surface tension of the liquid sample 2 containing an amphiphilic molecule such as a surfactant by the hanging drop method, thereby making the critical micelle of the amphiphilic molecule. The concentration is measured, and is configured by combining the supply device 200 with the surface tension measurement device 1 of the first embodiment. Accordingly, the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and only different parts will be described below.

  FIG. 6 is a schematic diagram of the critical micelle concentration measuring apparatus 3 according to the present embodiment. The supply device 200 combined with the surface tension measuring device 1 changes the concentration of the amphiphilic molecule in the liquid sample 2 containing the amphiphilic molecule and discharges the liquid sample 2 in which the concentration of the amphiphilic molecule is changed. This is supplied to the device 30. As shown in the figure, the supply device 200 includes a container 210, a liquid feed pump 220, a drainage valve 230, a pure water supply valve 240, and a liquid level sensor 250.

  The container 210 stores a predetermined amount of the liquid sample 2 in an appropriate sealed state. The liquid feed pump 220 is a pump having a known structure and feeds the liquid sample 2 from the container 210 to the discharge device 30. The liquid feed pump 220 is connected to the discharge device 30 via a liquid feed tube 222, and the liquid sample 2 is supplied to the discharge device 30 via this liquid feed tube 222.

  The drainage valve 230 is an electromagnetic valve having a known structure that is controlled by the computer 100 to open and close, and is connected to a drainage container (not shown). That is, the liquid sample 2 is discharged from the container 210 by opening the drain valve 230, and the discharge of the liquid sample 2 from the container 210 is stopped by closing the drain valve 230. Thereby, the liquid quantity of the liquid sample 2 in the container 210 can be adjusted.

  The pure water supply valve 240 is an electromagnetic valve having a known structure that is controlled by the computer 100 to open and close similarly to the drainage valve 230, and is connected to a pure water supply source (not shown). That is, pure water is supplied into the container 210 by opening the pure water supply valve 240, and supply of pure water into the container 210 is stopped by closing the pure water supply valve 240. Thereby, the density | concentration of the amphiphilic molecule | numerator in the liquid sample 2 in the container 210 can be adjusted.

  The liquid level sensor 250 is a sensor having a known structure that detects the liquid level height of the liquid sample 2 in the container 210. That is, the computer 100 controls the opening and closing of the drainage valve 230 and the pure water supply valve 240 based on the detection signal from the liquid level sensor 250, so that the liquid amount of the liquid sample 2 in the container 210 and the amphiphile The concentration of sex molecules is adjusted. In addition, the computer 100 grasps the supply amount of the liquid sample 2 to the ejection device 30 based on the detection signal from the liquid level sensor 250.

  The supply of pure water into the container 210 and the discharge of the liquid sample 2 from the container 210 may be performed by an appropriate pump or by gravity. Further, the supply device 200 is arranged above the surface tension measuring device 1 and an appropriate valve is provided in place of the liquid feed pump 220 so that the liquid sample 2 is supplied to the discharge device 30 by gravity. Also good. In addition, an appropriate stirring device or circulation device may be provided in the container 210 to stir the liquid sample 2 in the container 210.

  In the present embodiment, with such a configuration, it is possible to change the concentration of the amphiphilic molecules in the liquid sample 2 by the supply device 200 and supply the liquid sample 2 having different concentrations to the ejection device 30. Specifically, by opening the drain valve 230 and discharging a predetermined amount of the liquid sample 2 from the container 210, the pure water supply valve 240 is opened to supply a predetermined amount of pure water into the container 210. The concentration of amphiphilic molecules in the liquid sample 2 can be changed (diluted). Accordingly, the supply device 200 can create a plurality of types of liquid samples 2 having different surfactant concentrations in order from the higher concentration and supply the liquid sample 2 to the discharge device 30.

  In order to replace the liquid sample 2 in the discharge device 30 with the liquid sample 2 having a different concentration, it is necessary to completely discharge the liquid supply pump 220, the liquid supply pipe 222, and the remaining liquid in the discharge device 30. In this embodiment, by providing the tray 60 with a discharge pipe 62 connected to a drainage container (not shown), the residual liquid can be discharged to the tray 60. As a result, the liquid sample 2 can be quickly replaced with the liquid sample 2 because the previous residual liquid can be pushed out from the needle 32 of the discharge device 30 only by feeding the newly created liquid sample 2 with the liquid feed pump 220. Is possible.

  FIG. 7 is a block diagram showing the main functional configuration of the computer 100 in this embodiment. As shown in the figure, the computer 100 of the present embodiment includes a control device 110, an image processing device 120, and a data processing device 130 as main functional configurations.

  The control device 110 of the present embodiment controls the surface tension measuring device 1 and the supply device 200. Therefore, the control device 110 includes a density setting unit 117 and a supply replacement unit 118 as a specific functional configuration for controlling the supply device 200. The concentration setting means 117 controls the drain valve 230 and the pure water supply valve 240 based on the detection signal from the liquid level sensor 250 to change the concentration of amphiphilic molecules in the liquid sample 2 in the container 210, The predetermined density is set. Further, the supply replacement unit 118 controls the liquid feed pump 220 based on the detection signal from the liquid level sensor 250, and the amount of the liquid sample 2 that can completely replace the inside of the discharge device 30 with the liquid sample 2 having a new concentration. Supply.

  Further, the data processing apparatus 130 of the present embodiment includes a final surface tension acquisition unit 133 and a critical micelle concentration deriving unit 134 as a specific functional configuration for deriving the critical micelle concentration of the amphiphilic molecule. ing. The final surface tension acquisition unit 133 acquires the final surface tension, which is the final surface tension that has reached the equilibrium state, based on the temporal change data of the surface tension generated by the temporal change data generation unit 132, and The information is stored in the storage means of the computer 100 in association with the density. The critical micelle concentration deriving unit 134 derives the critical micelle concentration of the amphiphilic molecule based on the final surface tension at each concentration acquired by the final surface tension acquiring unit 133 and stores it in the storage unit of the computer 100. It is.

FIG. 8 is a schematic diagram showing the relationship between the concentration of amphiphilic molecules and the final surface tension in a semi-logarithmic graph. The critical micelle concentration is the concentration at which amphiphilic molecules begin to form micelles. That is, when the concentration of amphiphilic molecules is increased above the critical micelle concentration, the number of micelles increases, but the arrangement of the amphiphilic molecules at the interface maintains an equilibrium state, so the surface tension does not decrease any more, It will be kept substantially constant. Therefore, as shown in the figure, the semi-logarithmic graph is obtained by measuring the final surface tension (γ _e ) of the liquid sample 2 in which the concentration (C) of the amphiphilic molecule is set to a plurality of different concentrations C _{1 to} C _7. , The region where the final surface tension changes according to the concentration and the region where the final surface tension becomes substantially constant regardless of the concentration, the concentration at the boundary between the two regions is the critical micelle concentration CMC. Become. The critical micelle concentration deriving means 134 derives the critical micelle concentration by a known method such as derivation from an approximate expression.

  Next, a procedure for measuring the critical micelle concentration by the critical micelle concentration measuring apparatus 3 of the present embodiment will be described. FIG. 9 is a flowchart showing a procedure for measuring the critical micelle concentration by the critical micelle concentration measuring device 3. When measuring the critical micelle concentration, a liquid sample 2 containing amphiphilic molecules at a concentration higher than the critical micelle concentration expected in advance is prepared and stored in the container 210 of the supply device 200. .

  In the measurement of the critical micelle concentration by the critical micelle concentration measuring device 3, first, in step S30, the concentration of the amphiphilic molecule is set to a predetermined concentration (concentration setting step). Here, the concentration setting means 117 of the control device 110 controls the drain valve 230 and the pure water supply valve 240 to set a plurality of preset amphiphilic molecule concentrations in the liquid sample 2 in the container 210. Set to one of the densities. If the liquid sample 2 set to the initial set concentration is stored in the container 210, the concentration setting process is not performed in the first step S30.

  Next, in step S31, the liquid sample 2 is supplied to the ejection device 30, and the liquid sample 2 in the ejection device 30 is replaced (liquid sample supply replacement step). Here, the supply / substitution means 118 of the control device 110 controls the liquid feed pump 220 to supply the liquid sample 2 to the discharge device 30 and discharge the remaining liquid in the discharge device 30, etc. Sample 2 is replaced with a new liquid sample 2. When the discharge device 30 is left empty, the liquid sample 2 need only be supplied to the discharge device 30 in the first step S31.

  Next, in step S32, the surface tension of the liquid sample 2 in the discharge device 30 is measured (surface tension measuring step). Here, the temporal change of the surface tension is measured according to the procedure shown in FIG. 5, and the temporal change data of the surface tension is generated. Next, in step S33, the final surface tension is acquired from the temporal change data of the surface tension (final surface tension acquisition step). Here, the final surface tension acquisition means 133 of the data processing device 130 acquires the final surface tension that has reached the equilibrium state from the surface tension change data generated in step S32, and the set concentration set in step S30. Store in association with each other.

  Next, in step S34, it is determined whether or not the measurement of the surface tension has been completed for all of the preset density settings (all density end determination step). Here, if the final surface tension has been acquired for all the set densities, the process proceeds to step S35. If the set concentration for which the final surface tension has not been acquired remains, the process returns to step S30 to set the concentration of the surfactant in the liquid sample 2 in the container 210 to the next set concentration. The process of S33 is executed to obtain the final surface tension. In the present embodiment, due to the configuration of the supply device 200, measurement is performed in order from the higher set concentration.

  In step S35, the critical micelle concentration is derived (critical micelle concentration deriving step). Here, the critical micelle concentration deriving unit 134 of the data processing device 130 derives and stores the critical micelle concentration from the final surface tension acquired in step S33 and the set concentration associated therewith. Further, as necessary, the critical micelle concentration deriving unit 134 displays the derived critical micelle concentration on the display unit of the computer 100 together with the graph. By the above procedure, the critical micelle concentration of the amphiphilic molecule is measured. The acquisition of the final surface tension in step S33 may be performed collectively immediately before step S35.

  As described above, the surface tension measurement device 1 according to the first embodiment includes the ejection device 30 that ejects the liquid sample 2 from the tip (needle tip) 32 a of the tubular needle 32 and the tip 32 a of the needle 32. The surface tension of the liquid sample 2 is derived based on the image pickup device 40 that picks up the dropping droplet 2a, the control device 110 that controls the ejection device 30 and the image pickup device 40, and the image of the droplet 2a picked up by the image pickup device 40. The control device 110 discharges the liquid sample 2 to the discharge device 30 to suspend the droplet 2a having a predetermined start liquid amount from the tip 32a of the needle 32. Whenever the droplet 2a falls from the tip 32a of the needle 32, the liquid sample 2 is ejected by the ejection device 30 and a droplet 2a having a smaller correction liquid amount than the dropped droplet 2a is ejected from the tip 32a of the needle 32. Drooping The image processing apparatus 120 includes a droplet image acquisition unit 122 that acquires images of the droplets 2a at a plurality of time points, and a surface for each of the acquired images of the droplets 2a at a plurality of time points. Surface tension deriving means 123 for deriving tension.

  In addition, the surface tension measurement method according to the first embodiment includes an ejection device 30 that ejects the liquid sample 2 from the tip 32a of the tubular needle 32 and an image that images the droplet 2a that hangs down from the tip 32a of the needle 32. A surface tension measuring method in the surface tension measuring device 1 comprising the device 40, wherein the liquid sample 2 is ejected to the ejection device 30 and a droplet 2 a having a predetermined starting liquid amount is suspended from the tip 32 a of the needle 32. Each time the droplet 2a falls from the start droplet forming step S14 and the tip 32a of the needle 32, the liquid sample 2 is ejected to the ejection device 30, and the droplet 2a having a smaller correction liquid amount than the droplet 2a that has fallen is produced. A corrected droplet forming step S22 that hangs down from the tip 32a of the needle 32, a droplet image acquiring step S15 that acquires images of the droplet 2a at a plurality of time points captured by the imaging device 40, and a plurality of acquired times Has a surface tension derived step S16 of deriving the surface tension of the liquid sample 2, the each image of the droplet 2a in.

  With such a configuration, even a dynamic surface tension that changes over time can be easily measured by the hanging drop method. That is, by forming the smaller droplets 2a one after another and measuring the surface tension, it becomes possible to expand the measurable range even with the hanging drop method. Also, the surface tension can be measured over the entire range of change over time. Therefore, it is possible to easily measure the dynamic surface tension by effectively utilizing an existing contact angle measurement device or the like without preparing a dedicated device for other measurement methods.

  Further, the surface tension measuring device 1 includes a data processing device 130 that generates temporal change data of the surface tension of the liquid sample 2 based on the surface tension derived by the image processing device 120. The data processing device 130 is an image processing device. Effective surface tension selection means 131 is provided for selecting an effective surface tension from the surface tension derived by 120 based on the liquid amount of the droplet 2a. In this way, it is possible to select only the surface tension that can be appropriately derived from the droplets 2a having different sizes, so that the surface tension can be measured with high accuracy over a wide measurement range.

  Further, the data processing device 130 includes a temporal change data generation means 132 that generates temporal change data in which effective surface tensions are arranged in time series. In this way, the surface tension measured from a plurality of droplets 2a can be integrated into a total of time-dependent change data of the surface tension of the liquid sample 2, so that various evaluations and analyzes can be easily performed. Can be.

  In addition, the time-change data generating unit 132 generates time-change data by associating the elapsed time from the reference time for each droplet 2a with the effective surface tension. By doing so, it is possible to generate time-varying data by simply adding an effective surface tension associated with the elapsed time without requiring a complicated data linking process or the like.

  In addition, the control device 110 includes measurement end means 116 that ends the measurement when the change in the effective surface tension falls within a predetermined range. In this way, dynamic surface tension measurement can be fully automated.

  The correction liquid amount is set to 75 to 99% of the liquid amount of the dropped droplet 2a. By doing so, it is possible to appropriately set the effective surface tension range and appropriately expand the surface tension measurement range. That is, while maintaining high-precision measurement, the surface tension measurement range can be expanded and smooth and efficient measurement can be realized.

  The control device 110 also includes a falling droplet forming unit 111 that causes the discharge device 30 to discharge the liquid sample 2 until the droplet 2a falls from the tip 32a of the needle 32, and a droplet that the falling droplet forming unit 111 has dropped. And a start liquid amount setting means 112 for setting the start liquid amount based on the liquid amount 2a. By doing so, it is possible to easily and appropriately set the starting liquid amount, and to measure the initial surface tension of the liquid sample 2 with high accuracy.

  The critical micelle concentration measurement device 3 according to the second embodiment includes the surface tension measurement device 1 and a supply device 200 that supplies the liquid sample 2 containing amphiphilic molecules to the discharge device 30. The supply device 200 is configured to supply a plurality of types of liquid samples 2 having different amphiphilic molecule concentrations to the discharge device 30.

  In the critical micelle concentration measurement method according to the second embodiment, the ejection device 30 that ejects the liquid sample 2 from the tip 32a of the tubular needle 32 and the droplet 2a that hangs down from the tip 32a of the needle 32 are imaged. A method for measuring the critical micelle concentration using the surface tension measuring device 1 including the imaging device 40, wherein the concentration setting step S30 sets the concentration of the amphiphilic molecules in the liquid sample 2, and the concentration setting step S30. A surface tension measurement step S32 for measuring the surface tension of the liquid sample 2 having the set concentration, and the surface tension measurement step S32 causes the liquid sample 2 to be ejected by the ejection device 30 and a droplet having a predetermined starting liquid amount. The liquid droplet 2 is discharged to the discharge device 30 every time the droplet 2a falls from the tip 32a of the needle 32 and the start droplet forming step S14 in which the needle 2a is suspended from the tip 32a of the needle 32. A droplet forming step S22 in which a droplet 2a having a correction liquid amount smaller than the dropped droplet 2a is suspended from the tip 32a of the needle 32, and an image of the droplet 2a taken at a plurality of time points by the imaging device 40 are acquired. A droplet image obtaining step S15 and a surface tension deriving step S16 for deriving the surface tension of the liquid sample 2 for each of the obtained images of the droplet 2a at a plurality of time points are included.

  By adopting such a configuration, the dynamic surface tension of the liquid sample 2 containing amphiphilic molecules can be easily measured by the hanging drop method. Therefore, a large number of liquid samples 2 having different concentrations can be obtained. The critical micelle concentration, which requires the measurement of the dynamic surface tension, can be measured quickly and efficiently. Therefore, the critical micelle concentration can be easily measured by effectively utilizing an existing contact angle measurement device or the like without preparing a dedicated device for other measurement methods.

  Although the embodiments of the present invention have been described above, the surface tension measuring device and the surface tension measuring method, the critical micelle concentration measuring device and the critical micelle concentration measuring method of the present invention are limited to the above-described embodiments. However, it goes without saying that various changes can be made without departing from the scope of the present invention.

  For example, the shapes and arrangements of the members and mechanisms constituting the surface tension measuring device 1 or the critical micelle concentration measuring device 3 are not limited to those shown in the above embodiment, and other various shapes and arrangements A configuration can be employed.

  Further, the supply device 200 of the critical micelle concentration measuring device 3 is not limited to the structure shown in the above embodiment, and may have another known structure. For example, the supply apparatus 200 may include a plurality of containers that store a plurality of types of liquid samples 2 having different concentrations, and may be configured to supply the liquid samples 2 sequentially from the plurality of containers. .

  In addition, the functions and effects shown in the above embodiment are merely a list of the most preferable functions and effects resulting from the present invention, and the functions and effects of the present invention are not limited to these.

  The surface tension measuring device and surface tension measuring method, the critical micelle concentration measuring device and the critical micelle concentration measuring method of the present invention can be used in various fields dealing with amphiphilic molecules such as various surfactants.

DESCRIPTION OF SYMBOLS 1 Surface tension measuring device 2 Liquid sample 2a Droplet 3 Critical micelle concentration measuring device 30 Discharge device 32 Needle 32a Needle tip 40 Imaging device 110 Control device 111 Falling droplet formation means 112 Start liquid amount setting means 113 Start droplet formation means 114 Corrected droplet formation means 116 Measurement end means 120 Image processing device 122 Droplet image acquisition means 123 Surface tension derivation means 130 Data processing device 131 Effective surface tension selection means 132 Aging data generation means 200 Supply device S14 Start droplet formation step S15 Droplet image acquisition step S16 Surface tension derivation step S22 Correction droplet formation step S30 Concentration setting step S32 Surface tension measurement step

Claims (10)

A discharge device for discharging a liquid sample from the tip of a tubular needle;
An imaging device for imaging a droplet dripping from the tip of the needle;
A control device for controlling the ejection device and the imaging device;
An image processing device for deriving a surface tension of the liquid sample based on an image of the droplet imaged by the imaging device;
The controller is
Start liquid droplet forming means for discharging the liquid sample to the discharge device and dropping the liquid droplet of a predetermined start liquid amount from the tip of the needle;
Each time the droplet falls from the tip of the needle, a correction fluid that causes the liquid sample to be ejected by the ejection device and causes the droplet having a smaller amount of correction fluid to hang down from the tip of the needle. Droplet forming means,
The image processing apparatus includes:
Droplet image acquisition means for acquiring images of the droplets at a plurality of time points;
Surface tension deriving means for deriving surface tension for each of the obtained images of the droplets at a plurality of time points,
Surface tension measuring device. A data processing device that generates time-varying data of the surface tension of the liquid sample based on the surface tension derived by the image processing device;
The data processing apparatus includes an effective surface tension selecting unit that selects an effective surface tension based on a liquid amount of the droplet from the surface tension derived by the image processing apparatus.
The surface tension measuring device according to claim 1. The data processing apparatus includes a time-change data generating unit that generates time-change data in which the effective surface tensions are arranged in time series.
The surface tension measuring device according to claim 2. The time-change data generating means generates the time-change data by associating an elapsed time from a reference time point for each droplet with the effective surface tension.
The surface tension measuring device according to claim 3. The control device includes a measurement ending unit for ending the measurement when the change in the effective surface tension falls within a predetermined range.
The surface tension measuring device according to claim 2. The correction liquid amount is set to 75 to 99% of the liquid amount of the dropped droplet,
The surface tension measuring device according to any one of claims 1 to 5. The controller is
A falling droplet forming means for discharging the liquid sample to the discharge device until the droplet drops from the tip of the needle;
A starting liquid amount setting means for setting the starting liquid amount based on the liquid amount of the droplet dropped by the falling droplet forming means;
The surface tension measuring device according to any one of claims 1 to 6. A surface tension measuring device according to any one of claims 1 to 7,
A supply device for supplying the liquid sample containing amphiphilic molecules to the discharge device,
The supply device is configured to supply a plurality of types of the liquid samples having different concentrations of the amphiphilic molecules to the discharge device,
Critical micelle concentration measurement device. A discharge device for discharging a liquid sample from the tip of a tubular needle;
An imaging device for imaging a droplet that hangs down from the tip of the needle, and a surface tension measuring method in a surface tension measuring device comprising:
A start droplet forming step of discharging the liquid sample to the discharge device and dropping the droplet of a predetermined start liquid amount from the tip of the needle;
Each time the droplet falls from the tip of the needle, a correction fluid that causes the liquid sample to be ejected by the ejection device and causes the droplet having a smaller amount of correction fluid to hang down from the tip of the needle. A drop formation step;
A droplet image acquisition step of acquiring images of the droplets at a plurality of time points captured by the imaging device;
A surface tension deriving step for deriving the surface tension of the liquid sample for each of the acquired images of the droplets at a plurality of time points,
Surface tension measurement method. A discharge device for discharging a liquid sample from the tip of a tubular needle;
An imaging device for imaging a droplet hanging from the tip of the needle, and a method for measuring a critical micelle concentration using a surface tension measuring device comprising:
A concentration setting step for setting the concentration of amphiphilic molecules in the liquid sample;
A surface tension measurement step for measuring a surface tension of the liquid sample having a concentration set in the concentration setting step,
The surface tension measuring step includes
A start droplet forming step of discharging the liquid sample to the discharge device and dropping the droplet of a predetermined start liquid amount from the tip of the needle;
Each time the droplet falls from the tip of the needle, a correction fluid that causes the liquid sample to be ejected by the ejection device and causes the droplet having a smaller amount of correction fluid to hang down from the tip of the needle. A drop formation step;
A droplet image acquisition step of acquiring images of the droplets at a plurality of time points captured by the imaging device;
A surface tension deriving step for deriving the surface tension of the liquid sample for each of the acquired images of the droplets at a plurality of time points,
Critical micelle concentration measurement method.

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