Method and system for imaging fine water droplets using atomic force microscope

Abstract

One embodiment of the present invention provides a method in which deionized water is positioned in a space between a holder and a stage of an atomic force microscope, the deionized water is evaporated to form fine water droplets on the surface of a sample, and the fine water droplets formed on the surface of the sample are imaged by being scanned with the atomic force microscope.

Description

Method and system for imaging microdroplets using atomic force microscopy

[0001] The present invention relates to a method for imaging microdroplets, and more particularly, to a method and system for imaging microdroplets using an atomic force microscope.

[0002] In order to measure the contact angle of water between a conventional substrate and a two-dimensional sample, a water droplet is directly applied to the sample using the sessile drop method and a contact angle analyzer is used. At this time, a camera is used to obtain the contact angle formed between the substrate and the edge of the water droplet through a side image of the water droplet.

[0003] However, this method can only be used when the size of the water droplet is several millimeters or larger, and there is a problem in that it is difficult to use when measuring the contact angle of a sample with a size of micrometers (e.g., micrometer-sized particles) or when measuring the contact angle of a droplet of a very small size.

[0004] In addition, the existing method of imaging nanobubbles and nanodroplets using AFM requires the use of a complex method called the solvent exchange method, and has the disadvantage of being applicable only to hydrophobic sample surfaces.

[0005] Therefore, in order to compensate for the aforementioned shortcomings, research is needed on a method that can image the surface of nano-sized water droplets in real time using AFM and measure the contact angle using this to analyze the wettability of materials at the nano level.

[0006] [Prior Art Literature]

[0007] Republic of Korea Patent Publication No. 10-2020-0081433

[0008] The technical problem to be achieved by the present invention is to solve the problems of the above-mentioned conventional technology, and to provide a method for imaging nano-sized micro-droplets using an atomic force microscope.

[0009] In addition, a technical problem to be achieved by the present invention is to provide a micro-droplet imaging system using an atomic force microscope.

[0010] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0011] In order to achieve the above technical task, one embodiment of the present invention provides a method for imaging microdroplets using an atomic force microscope.

[0012] In one embodiment of the present invention, a method for imaging microdroplets using an atomic force microscope may include the steps of: positioning deionized water (DI water) in a space between a holder and a stage of an atomic force microscope; evaporating the DI water to form microdroplets on a surface of a sample; and scanning the microdroplets formed on the surface of the sample using the atomic force microscope to image them.

[0013] Additionally, in one embodiment of the present invention, the diameter of the micro-droplets may range from 100 nm to 20 μm.

[0014] Additionally, in one embodiment of the present invention, in the step of positioning the deionized water, the temperature of the stage can be cooled to 0°C to 1°C.

[0015] Additionally, in one embodiment of the present invention, the cooling rate for cooling the stage may be 0.1°C / s to 1°C / s.

[0016] Additionally, in one embodiment of the present invention, in the step of forming fine water droplets on the surface of the sample, the deionized water may be evaporated and stabilized for 5 to 20 minutes to form fine water droplets on the surface of the sample.

[0017] Additionally, in one embodiment of the present invention, the sample may include at least one member selected from the group consisting of lithium tantalite (LiTaO3) single crystal and NiFeLDH catalyst particles / SiNx substrate.

[0018] In addition, in one embodiment of the present invention, in the micro-droplet imaging method using the atomic force microscope, the Target percent may be set to 5% to 10%; the Target amplitude may be set to 66 nm to 110 nm; the Setpoint may be set to 40 nm to 80 nm; the Scan rate may be set to 0.1 Hz to 1 Hz; and the Scan angle may be set to 0˚ to 90˚.

[0019] In order to achieve the above technical task, another embodiment of the present invention provides a micro-droplet imaging system using an atomic force microscope.

[0020] In one embodiment of the present invention, a micro-droplet imaging system using an atomic force microscope may include: an injection unit that injects deionized (DI) water into a space between a holder and a stage of an atomic force microscope; a droplet formation unit that evaporates the DI water injected into the injection unit to form a plurality of micro-droplets on a sample surface; a measurement unit that scans the micro-droplets formed on the sample surface of the droplet formation unit; an output unit that outputs a surface topography image, an amplitude image, and a line profile of the micro-droplets scanned through the measurement unit; and an analysis unit that analyzes a contact angle of each micro-droplet with the sample surface using the surface topography image, the amplitude image, and the line profile of the micro-droplet.

[0021] In addition, in one embodiment of the present invention, the atomic force microscope settings of the measuring unit may be set to: Target percent from 5% to 10%; Target amplitude from 66 nm to 110 nm; Setpoint from 40 nm to 80 nm; Scan rate from 0.1 Hz to 1 Hz; and Scan angle from 0˚ to 90˚.

[0022] In addition, in one embodiment of the present invention, the temperature of the stage of the placement unit is cooled to 0°C to 1°C so that fine water droplets are not formed in an area other than the sample surface of the water droplet formation unit, and evaporation of the fine water droplets by the probe when scanning with an atomic force microscope of the measurement unit can be delayed.

[0023] A method for imaging microdroplets using an atomic force microscope according to one embodiment of the present invention can induce the spontaneous formation of nano-sized droplets, thereby enabling surface imaging and measurement of a contact angle therethrough, thereby enabling the wettability of a material to be confirmed at the nano level through nano-sized droplets, enabling analysis on a smaller scale. This can provide the effect of enabling water droplet imaging even on the surface of a sample having a size of about 1 μm, thereby enabling analysis of the surface wettability of a single particle.

[0024] In addition, the method for imaging microdroplets using an atomic force microscope according to one embodiment of the present invention can be utilized in an operando system because it directly measures droplets in a formed state, thereby providing an effect that can be developed into real-time analysis.

[0025] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0026] Figure 1 is a flowchart showing the steps of a method for imaging microdroplets using an atomic force microscope according to one embodiment of the present invention.

[0027] FIG. 2 is an image of the surface topography of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0028] FIG. 3 is an image of the amplitude of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0029] FIG. 4 is a 3D topography image of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate, measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0030] FIG. 5 is a surface topography image showing the contact angle at each point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate, measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0031] FIG. 6 is a line profile showing the contact angle at the first point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0032] FIG. 7 is a line profile showing the contact angle at the second point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate, measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0033] FIG. 8 is a line profile showing the contact angle at the third point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0034] FIG. 9 is an image of the surface topography of microdroplets on a NiFeLDH catalyst particle / SiNx substrate (NiFeLDH catalyst particles on SiNx substrate) measured using a microdroplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0035] FIG. 10 is a line profile of a micro-droplet on a NiFeLDH catalyst particle / SiNx substrate measured using a micro-droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0036] FIG. 11 is a 3D topography image of a micro-droplet on a NiFeLDH catalyst particle / SiNx substrate (NiFeLDH catalyst particles on SiNx substrate) measured using a micro-droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0037] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0038] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that it may include other components, unless otherwise specifically stated.

[0039] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0040] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0041] Conventional methods for measuring the contact angle of water on substrates and two-dimensional samples can only measure when the size of the water droplet is several millimeters or larger, and cannot be free from the problem that measurement is only possible on hydrophobic samples.

[0042] To solve these problems, the present invention provides a method and system for imaging microdroplets using an atomic force microscope, which can measure the diameter of droplets even if they are nano-sized and can measure even if the sample is not hydrophobic.

[0043] Below, the present invention will be described with reference to the drawings presented in this specification. Note that the drawings may be exaggerated to illustrate the features of the present invention. In such cases, it is preferable to interpret them in light of the overall intent of this specification.

[0044]

[0045] A method for imaging microdroplets using an atomic force microscope according to one embodiment of the present invention is described.

[0046] Figure 1 is a flowchart showing the steps of a method for imaging microdroplets using an atomic force microscope according to one embodiment of the present invention.

[0047] Referring to FIG. 1, a method for imaging microdroplets using an atomic force microscope according to one embodiment of the present invention may include a step (S100) of positioning deionized water (DI water) in a space between a holder and a stage of an atomic force microscope; a step (S200) of evaporating the deionized water to form microdroplets on the surface of a sample; and a step (S300) of scanning and imaging the microdroplets formed on the surface of the sample using the atomic force microscope.

[0048]

[0049] The first step may include placing deionized water (DI water) in the space between the holder and the stage of the atomic force microscope. (S100)

[0050] Before placing deionized water in the space between the holder and the stage of the atomic force microscope, it is desirable to first cool the stage temperature.

[0051] This works by lowering the temperature of the stage to allow micro-droplets to spontaneously form on the sample surface, similar to how a window fogs up on a cold day, while simultaneously delaying evaporation by the probe during scanning using an atomic force microscope, thereby lowering the temperature of the sample positioned on the stage.

[0052] Therefore, in the step of positioning the deionized water, the temperature of the stage can be cooled to 0°C to 1°C, and preferably, to 0.4°C to 0.6°C.

[0053] At this time, if the temperature is lower than the aforementioned cooling range, a problem may occur in which fine water droplets formed on the surface of the sample located on the stage freeze, and if the temperature is higher than the cooling range, a problem may occur in which fine water droplets formed on the surface of the sample evaporate.

[0054] Therefore, the temperature of the stage can be cooled to a range of 0°C to 1°C, but not below 0°C, and preferably 0.4°C to 0.6°C.

[0055] Meanwhile, the cooling rate for cooling the stage is not particularly limited, but may preferably be 0.1°C / s to 1°C / s.

[0056] This is because if the cooling rate exceeds the aforementioned range, the equipment may be damaged.

[0057] After the stage is cooled under the conditions described above, an appropriate amount of deionized water can be placed around the stage using a pipette and a holder with a tip can be mounted.

[0058] At this time, it is desirable to place an appropriate amount of deionized water in the space between the holder and the stage, as this can maintain an appropriate vapor pressure to form water droplets and delay evaporation of the formed water droplets.

[0059] Therefore, the amount of deionized water is not particularly limited, but when setting the volume range using a pipette, it is preferable to place 100 μl to 200 μl of deionized water around the stage.

[0060] This is because if the range described above is exceeded, the evaporation of deionized water may not occur properly, which may delay the formation of microdroplets, or too many microdroplets may be formed, which may affect precise measurement.

[0061]

[0062] The second step may include a step of evaporating the deionized water to form fine water droplets on the surface of the sample. (S200)

[0063] To form micro-droplets on the surface of the sample, it is necessary to wait for the deionized water around the stage to evaporate and for the evaporated deionized water to stabilize.

[0064] Therefore, in the step of forming fine water droplets on the surface of the sample, the deionized water can be evaporated and stabilized for 5 to 20 minutes to form fine water droplets on the surface of the sample.

[0065] At this time, if the evaporation time of the deionized water is less than 5 minutes, a problem may occur in which water droplets are formed excessively large or coalesce and grow before stabilization, and if the evaporation time exceeds 20 minutes, a problem may occur in which water droplets evaporate easily from the sample and form on the stage surface because the temperature of the stage itself is lower than that of the sample surface.

[0066] Therefore, the diameter of the micro-water droplets formed on the surface of the sample during the evaporation and stabilization process within the aforementioned time range may be 100 nm to 20 μm.

[0067] At this time, if the diameter of the microdroplet exceeds the above-mentioned range, the height of the droplet increases proportionally as the diameter of the microdroplet increases, which may cause problems in tracking the surface by the AFM tip.

[0068] For example, problems may arise with penetrating fine water droplets.

[0069] In addition, since the scan range of Cypher ES (Asylum research) used in the experimental example described later is a maximum of 30 μm*30 μm in the XY direction, if it is excessively large, a problem may arise in which imaging becomes difficult, and there is also the point that it is difficult to call water droplets larger than several tens of μm as micro-droplets.

[0070] Therefore, it is desirable to proceed with the present invention by forming fine droplets having a diameter within the aforementioned range.

[0071] Meanwhile, the degree to which fine water droplets are formed may vary depending on the sample, and at this time, the sample is not particularly limited, but preferably, the sample may include at least one member from the group consisting of lithium tantalite (LiTaO3) single crystal and NiFeLDH catalyst particles / SiNx substrate.

[0072] At this time, the reason why it is desirable to use the aforementioned type of sample is that the lithium tantalate single crystal sample is a ferroelectric with hydrophilic properties and has an overall flat surface, and NiFeLDH is a catalyst with plate-shaped particles and can be manufactured to a size of about 1 μm, making it suitable for imaging nano-sized water droplets.

[0073]

[0074] As a final step, a step of scanning and imaging the micro-droplets formed on the surface of the sample using the atomic force microscope may be included. (S300)

[0075] At this time, the setting values ​​for imaging microdroplets using the atomic force microscope may be set to, for example, Target percent of 5% to 10%, Target amplitude of 66 nm to 110 nm, Setpoint of 40 nm to 80 nm, Scan rate of 0.1 Hz to 1 Hz, and Scan angle of 0˚ to 90˚.

[0076] Here, the scan angle referred to here means 0 degrees when the scanning direction is the axial direction of the cantilever, and 90 degrees when it is vertical. This is because the range of the scan angle is not meaningful and it is convenient to set the position to be measured before scanning the water droplet, and accordingly, the scan angle is not particularly limited.

[0077] In addition, if the Target percent is negative, it is an area where the tip and the sample surface are close and a repulsive force acts, and if it is positive, it is an area where an attractive force acts. In order to minimize interference by the tip on the surface of the water droplet, 5 to 10% is appropriate, and it is more desirable to set it to 5%. However, if the Target percent is excessively high, a problem of poor imaging may occur.

[0078] In addition, the target amplitude and setpoint numerical ranges are converted from the mV values ​​in the AFM equipment (Cypher ES) used in the experimental examples of the present invention. For example, when using the Cypher ES equipment, the target amplitude can be 600 mV to 1000 mV; the setpoint can be 400 mV to 800 mV, and these are converted to nm values ​​for use in other AFM equipment.

[0079] Specifically, the nm is converted to a unit by multiplying the Target amplitude by Amp InvOLS and the Setpoint by InvOLS. Since AmpInvOLS and InvOLS are 109 nm / V and 100 nm / V, respectively, when converted, the Target amplitude can be expressed as 66 nm to 110 nm, and the Setpoint can be expressed as 40 nm to 80 nm.

[0080]

[0081] A microdroplet imaging system using an atomic force microscope according to one embodiment of the present invention is described.

[0082] The micro-droplet imaging system using an atomic force microscope according to the present invention can apply all of the contents described in the micro-droplet imaging method using an atomic force microscope described above, and although detailed descriptions of overlapping parts have been omitted, the same can be applied even if the descriptions are omitted.

[0083] A micro-droplet imaging system using an atomic force microscope according to one embodiment of the present invention may include: an injection unit that injects deionized (DI) water into a space between a holder and a stage of an atomic force microscope; a droplet formation unit that evaporates the deionized water injected into the injection unit to form a plurality of micro-droplets on a sample surface; a measurement unit that scans the micro-droplets formed on the sample surface of the droplet formation unit; an output unit that outputs a surface topography image, an amplitude image, and a line profile of the micro-droplets scanned through the measurement unit; and an analysis unit that analyzes a contact angle of each micro-droplet with the sample surface using the surface topography image, the amplitude image, and the line profile of the micro-droplet.

[0084] The injection section is positioned by injecting an appropriate amount of deionized water into the space between the holder and the stage of the atomic force microscope, whereupon evaporation occurs and microdroplets can be formed in the droplet formation section.

[0085] In addition, in the case of the water droplet forming portion, the sample in which fine water droplets are formed may include at least one member selected from the group consisting of lithium tantalite (LiTaO3) single crystal and NiFeLDH catalyst particles / SiNx substrate.

[0086] Additionally, the measuring unit can scan micro-droplets formed on the sample surface using an atomic force microscope probe.

[0087] In addition, the output unit can output a topography image, an amplitude image, and a line profile of a micro-droplet. For example, any image capable of visualizing a micro-droplet can be output without limitation.

[0088] At this time, the atomic force microscope settings of the above-mentioned measuring unit can be set to: Target percent from 5% to 10%; Target amplitude from 66 nm to 110 nm; Setpoint from 40 nm to 80 nm; Scan rate from 0.1 Hz to 1 Hz; and Scan angle from 0˚ to 90˚.

[0089] In addition, by cooling the temperature of the stage of the above-mentioned arrangement to 0°C to 1°C, micro-droplets are not formed in an area other than the sample surface of the above-mentioned water droplet formation section, and evaporation of the micro-droplets by the probe when scanning with an atomic force microscope of the above-mentioned measurement section can be delayed.

[0090]

[0091] Hereinafter, the present invention will be described in more detail through examples and experimental examples. These examples and experimental examples are intended solely to illustrate the present invention, and the scope of the present invention is not limited by these examples and experimental examples.

[0092]

[0093] Example

[0094] Microdroplet imaging method using atomic force microscope

[0095] First, the stage temperature of the atomic force microscope (Environmental AFM (Cypher ES, Oxford instrument) equipped with a temperature controller) was set to 0.5 °C and the cooling rate to 0.1 °C / s.

[0096] When the stage temperature reached 0.5 °C, an appropriate amount of DI water (100 μl to 200 μl) was placed around the stage using a pipette, and a holder with a tip was mounted.

[0097] At this time, the tip used was AR10T-NCHR (Nanosensors).

[0098] Afterwards, we waited for 5 minutes to allow water droplets to form and stabilize on the sample.

[0099] At this time, the sample used was lithium tantalite (LiTaO3) single crystal or NiFeLDH catalyst particles / SiNx substrate.

[0100] Next, the attractive mode was used with the Target percent set to 5% to prevent the Tip and the water surface from getting too close, and the Target amplitude was set to 800 mV, the setpoint to 600 mV, and the scan rate to 0.5 Hz.

[0101] Additionally, the scan angle was set to 0°, and the appropriate location was scanned to image the microdroplets.

[0102]

[0103] Experimental example

[0104] Lithium tantalite (LiTaO3) single crystal substrate

[0105] FIG. 2 is an image of the surface topography of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0106] FIG. 3 is an image of the amplitude of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0107] Referring to FIGS. 2 and 3, it can be confirmed that a micro water droplet is imaged on a lithium tantalite (LiTaO3) single crystal substrate, and the surface shape and amplitude images are measured.

[0108]

[0109] FIG. 4 is a 3D topography image of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate, measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0110] The 3D surface topography image confirms that microdroplets of various sizes have formed on the sample.

[0111]

[0112] FIG. 5 is a surface topography image showing the contact angle at each point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate, measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0113] Referring to FIG. 5, it can be confirmed that a first point, a second point, and a third point are set for measuring the contact angle of a specific micro-water droplet with the lithium tantalate single crystal substrate at a portion where the micro-water droplet comes into contact with the lithium tantalate single crystal substrate.

[0114]

[0115] FIG. 6 is a line profile showing the contact angle at the first point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0116] Referring to Fig. 6, it can be confirmed that the contact angle between the first point of the micro water droplet and the lithium tantalate single crystal substrate was measured to be 6.7° and 6.1°.

[0117] FIG. 7 is a line profile showing the contact angle at the second point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate, measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0118] Referring to Fig. 7, it can be confirmed that the contact angles between the second point of the micro water droplet and the lithium tantalate single crystal substrate are measured as 5° and 4.6°.

[0119] FIG. 8 is a line profile showing the contact angle at the third point of a micro-water droplet on a lithium tantalite (LiTaO3) single crystal substrate measured using a micro-water droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0120] Referring to Fig. 8, it can be confirmed that the contact angle between the third point of the micro water droplet and the lithium tantalate single crystal substrate was measured to be 6.2° and 7.5°.

[0121] Through this, it can be confirmed that the contact angle of micro-droplets can be measured using the micro-droplet imaging method using an atomic force microscope of the present invention.

[0122]

[0123] NiFeLDH catalyst particles on SiNx substrate

[0124] FIG. 9 is an image of the surface topography of microdroplets on a NiFeLDH catalyst particle / SiNx substrate (NiFeLDH catalyst particles on SiNx substrate) measured using a microdroplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0125] Looking at Figure 9, it can be confirmed that fine water droplets are formed on the surface of the NiFeLDH catalyst particles / SiNx substrate.

[0126]

[0127] FIG. 10 is a line profile of a micro-droplet on a NiFeLDH catalyst particle / SiNx substrate measured using a micro-droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0128] Looking at Figure 10, it can be confirmed that measurement of the height, diameter, and surface angle of micro-droplets is possible.

[0129]

[0130] FIG. 11 is a 3D topography image of a micro-droplet on a NiFeLDH catalyst particle / SiNx substrate (NiFeLDH catalyst particles on SiNx substrate) measured using a micro-droplet imaging method using an atomic force microscope according to one embodiment of the present invention.

[0131] As shown in Fig. 11, it can be confirmed that imaging of microdroplets is possible through a 3D topography image of microdroplets on NiFeLDH catalyst particles / SiNx substrate.

[0132]

[0133] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0134] The scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A step of placing deionized water (DI water) in the space between the holder and the stage of the atomic force microscope; A step of evaporating the deionized water to form fine water droplets on the surface of the sample; and A method for imaging microdroplets using an atomic force microscope, characterized in that it comprises a step of scanning and imaging microdroplets formed on the surface of the sample using the atomic force microscope.

2. In paragraph 1, A method for imaging microdroplets using an atomic force microscope, characterized in that the diameter of the microdroplets comprises 100 nm to 20 μm.

3. In paragraph 1, In the step of positioning the above deionized water, A method for imaging microdroplets using an atomic force microscope, characterized in that the temperature of the stage is cooled to 0°C to 1°C.

4. In paragraph 3, A method for imaging microdroplets using an atomic force microscope, characterized in that the cooling rate for cooling the stage is 0.1°C / s to 1°C / s.

5. In paragraph 1, In the step of forming fine water droplets on the surface of the above sample, A method for imaging microdroplets using an atomic force microscope, characterized in that the deionized water is evaporated and stabilized for 5 to 20 minutes to form microdroplets on the surface of the sample.

6. In paragraph 1, A method for imaging microdroplets using an atomic force microscope, characterized in that the sample comprises at least one member selected from the group consisting of lithium tantalite (LiTaO3) single crystal and NiFeLDH catalyst particles on SiNx substrate.

7. In paragraph 1, In the above method for imaging microdroplets using an atomic force microscope, Target percent is 5% to 10%; Target amplitude is 66 nm to 110 nm; Setpoint is 40 nm to 80 nm; Scan rate is 0.1Hz to 1Hz; and A method for imaging microdroplets using an atomic force microscope, characterized in that the scan angle is set to 0˚ to 90˚.

8. In a microdroplet imaging system using an atomic force microscope, An injection unit for injecting deionized water (DI water) into the space between the holder and the stage of an atomic force microscope; A water droplet forming section in which deionized water injected into the above injection section evaporates to form multiple fine water droplets on the sample surface; A measuring unit that scans fine water droplets formed on the sample surface of the water droplet forming unit; An output unit that outputs a surface topography image, an amplitude image, and a line profile of a micro-droplet scanned through the above measurement unit; and A microdroplet imaging system using an atomic force microscope, characterized in that it includes an analysis unit that analyzes the contact angle of each microdroplet with the sample surface using the surface shape image, amplitude image, and line profile of the microdroplet.

9. In paragraph 8, The above measurement unit uses an atomic force microscope, and according to the settings of the atomic force microscope Target percent is 5% to 10%; Target amplitude is 66 nm to 110 nm; Set point is 40 nm to 80 nm; Scan rate is 0.1Hz to 1Hz; and A microdroplet imaging system using an atomic force microscope, characterized in that the scan angle is set to 0˚ to 90˚.

10. In paragraph 8, A micro-droplet imaging system using an atomic force microscope, characterized in that the temperature of the stage of the above-mentioned arrangement is cooled to 0°C to 1°C so that micro-droplets are not formed in an area other than the sample surface of the above-mentioned water droplet formation section, and evaporation of the micro-droplets by the probe is delayed when scanning with an atomic force microscope of the above-mentioned measurement section.

Images