Micro manipulator using smectic liquid crystal

Abstract

To provide a micro manipulator using smectic liquid crystal that can strengthen interfacial force and be used for precise operation for a fine material.SOLUTION: A micro manipulator using smectic liquid crystal includes: smectic liquid crystal S; and interface generation means 2 for generating an interface F between an isotropic phase IP in a liquid state and a liquid crystal phase SP in a liquid crystal state in the smectic liquid crystal S. Generating an interface F between the isotropic phase IP and the liquid crystal phase SP in the smectic liquid crystal S can hold or move a substance with the interface F. Moreover, interfacial force can be strengthened, thereby enhancing capability of holding or moving a substance.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a micromanipulator using smectic liquid crystal. More specifically, it relates to a micromanipulator that utilizes the interfacial force at the interface between smectic liquid crystal and isotropic phase.

Background Art

[0002] Liquid crystalline substances can take a liquid state (isotropic phase) in which molecules are isotropic (disordered) and a liquid crystal state (liquid crystal phase) in which molecules are oriented in a certain direction, and can take a state in which the isotropic phase and the liquid crystal phase coexist with an interface therebetween. At such an interface, a force (hereinafter sometimes simply referred to as interfacial force) that attempts to exclude a microscale object from the liquid crystal phase to the isotropic phase is generated. For example, the interfacial force generated between the nematic liquid crystal phase and the isotropic phase is caused by the disturbance of the molecular orientation field in the nematic liquid crystal phase region, and the nematic liquid crystal phase region acts to exclude a microscale object to the isotropic phase region.

[0003] As a technique that utilizes such an interfacial force generated between the nematic liquid crystal phase and the isotropic phase, the technique of Patent Document 1 has been developed. Specifically, by generating a temperature gradient in a nematic liquid crystal such as 4-pentyl-4'-cyanobiphenyl to form an interface (phase transition region) between the liquid crystal phase and the isotropic phase, and changing the temperature gradient in the nematic liquid crystal to move the interface, a technique is disclosed in which an object in the nematic liquid crystal can be moved together with the phase transition region.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, as a technology for precisely manipulating fine substances such as living cells and microparticles, technologies using MEMS have been developed. However, even these technologies are not sufficient for precisely manipulating fine substances, and there is a need for a technology that can more appropriately perform precise manipulation of fine substances.

[0006] For example, it is also promising to use a method utilizing liquid-liquid crystal phase transition, such as the technology of Patent Document 1, for precise manipulation of fine substances. However, the nematic liquid crystal disclosed in Patent Document 1 has the property that rod-shaped (or disk-shaped) molecules have orientation order but no positional order, so the interfacial force is relatively weak. If a substance with a stronger interfacial force can be obtained, it is preferable for precise manipulation of fine substances.

[0007] In view of the above circumstances, an object of the present invention is to provide a micromanipulator using smectic liquid crystal that can enhance the interfacial force and can be used for precise manipulation of fine substances.

Means for Solving the Problems

[0008] The micromanipulator using smectic liquid crystal according to the first invention includes smectic liquid crystal and an interface generating means for generating an interface between an isotropic phase in a liquid state and a liquid crystal phase in a liquid crystal state in the smectic liquid crystal, and the interface generating means has a function of generating a liquid crystal phase at the upper part, an isotropic phase at the lower part, and an interface between the two. The micromanipulator using smectic liquid crystal according to the second invention is characterized in that, in the first invention, the interface generating means has a function of moving the interface of the smectic liquid crystal in the vertical direction.

Effects of the Invention

[0009] According to the first invention, if an interface between an isotropic phase and a liquid crystal phase is generated in the smectic liquid crystal, it becomes possible to hold or move an object by the interface. According to the second invention, if the interface is moved, it becomes possible to move an object by the interface.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0011] Next, embodiments of the present invention will be described with reference to the drawings. In addition, in FIGS. 1 to 3, for the sake of clarity of the configuration of each part, the relative dimensions of each part do not match the actual ones.

[0012] <The micromanipulator 1 using the smectic liquid crystal of this embodiment> First, based on FIGS. 1 to 3, the micromanipulator 1 using the smectic liquid crystal of this embodiment (hereinafter sometimes simply referred to as the micromanipulator 1 of this embodiment) will be described.

[0013] In FIGS. 1 and 2, the case where the smectic liquid crystal S is disposed on the fixed plate BP is shown. However, in the apparatus to which the micromanipulator 1 of the present embodiment is applied, the member for disposing the smectic liquid crystal S is not particularly limited. For example, as shown in FIG. 3, the smectic liquid crystal S may be in a state of being accommodated in a box-shaped member 10, and is not particularly limited.

[0014] <Interface generating means 2> As shown in FIG. 1, an interface generating means 2 is provided on the lower surface of the fixed plate BP. This interface generating means 2 has a function of generating a temperature gradient in the smectic liquid crystal S to generate a liquid crystal phase SP and an isotropic phase IP (that is, a phase in a liquid state), and generating an interface F (phase transition region) between the two.

[0015] This interface generating means 2 includes a heating part 3 such as a heater and a cooling part 4 such as a chiller. The heating part 3 can heat the smectic liquid crystal S via the fixed plate BP, and has at least a function of heating the smectic liquid crystal S to a temperature higher than the phase transition temperature Tc between the liquid crystal phase SP and the isotropic phase IP. Further, the cooling part 4 can cool the smectic liquid crystal S via the fixed plate BP, and is disposed at a position spaced apart from the heating part 3 to some extent. This cooling part 4 has at least a function of cooling the smectic liquid crystal S to a temperature lower than the phase transition temperature Tc between the liquid crystal phase SP and the isotropic phase IP. The heating part 3 and the cooling part 4 are connected to a control part 5 that adjusts the temperatures of both to adjust the temperature gradient formed in the smectic liquid crystal S.

[0016] Therefore, by adjusting the heating by the heating part 3 and the cooling by the cooling part 4 by the control part 5 of the interface generating means 2, the interface F can be generated at a desired position in the smectic liquid crystal S, and the interface F can also be moved.

[0017] Note that the interface generating means 2 only needs to have a function of generating a liquid crystal phase SP and an isotropic phase IP in the smectic liquid crystal S and generating an interface F between the two, and is not limited to the method of providing a heating unit 3 on one side and a cooling unit 4 on the other as described above. For example, a method of providing heating and cooling devices (for example, Peltier elements) on both parts corresponding to the heating unit 3 and the cooling unit 4 in FIG. 1 so that the heating position and the cooling position can be changed can also be adopted. Further, as the interface generating means 2, one that can apply a magnetic field or an electric field to the smectic liquid crystal S may be adopted. That is, a device that applies a magnetic field or an electric field to the smectic liquid crystal S in an isotropic state to forcibly generate a polymer alignment state in the smectic liquid crystal S may be used as the interface generating means 2. With such an interface generating means 2, the liquid crystal phase SP can be generated by a magnetic field or an electric field in the smectic liquid crystal S in an isotropic state to generate the interface F. Moreover, by adjusting the position and intensity of the applied magnetic field or electric field, the position where the interface F is generated can be adjusted, so that the degree of freedom in the position where the interface F is provided can be increased.

[0018] <Regarding the smectic liquid crystal S> In the micromanipulator 1 of the present embodiment, the smectic liquid crystal S is used. This smectic liquid crystal S has the property that the nematic liquid crystal has rod-shaped (or disk-shaped) molecules and has an orientation order but no positional order, whereas the smectic liquid crystal has a layered structure and has both an orientation order and a positional order. Therefore, the smectic liquid crystal can generate a larger interfacial force at the interface F between the liquid crystal phase SP and the isotropic phase IP than the nematic liquid crystal.

[0019] With the above configuration, as shown in Fig. 1(A), a part of the smectic liquid crystal S (the right region in Fig. 1(A)) can be heated to a temperature higher than the phase transition temperature Tc by the heating unit 3, and a part of the smectic liquid crystal S (the left region in Fig. 1(A)) can be cooled to a temperature lower than the phase transition temperature Tc by the cooling unit 4. Then, a temperature gradient Tg in which the temperature decreases from the right region to the left region is formed in the smectic liquid crystal S. Since it is in the liquid (isotropic phase) at a temperature higher than the phase transition temperature Tc and in the liquid crystal (liquid crystal phase) at a temperature lower than the phase transition temperature Tc, an isotropic phase IP region is formed on the right side and a liquid crystal phase SP region is formed on the left side in the smectic liquid crystal S, and an interface F is formed between the two regions.

[0020] Then, by adjusting the thermal energy taken from the smectic liquid crystal S by the cooling unit 4 and the thermal energy supplied to the smectic liquid crystal S from the heating unit 3 by the control unit 5 of the interface generation means 2, the temperature gradient Tg formed in the smectic liquid crystal S can be freely adjusted. Therefore, by simply adjusting the temperature of the heating unit 3 and the temperature of the cooling unit 4, the position of the interface F formed between the cooling unit 4 and the heating unit 3 can be adjusted. That is, by simply adjusting the temperature of the heating unit 3 and the temperature of the cooling unit 4, the interface F can be generated at a desired position, and the interface F can also be moved in a desired direction and at a desired speed at a desired timing.

[0021] <Usage method of the micromanipulator 1 of the present embodiment> The micromanipulator 1 of this embodiment, for example, as shown in FIG. 3, contains a smectic liquid crystal S in a vertically extending container 10 or the like, and the above-described fixed plate BP and the interface generation means 2 may be provided on the side surface of the container 10. Specifically, the side surface of the container 10 and the fixed plate BP are arranged to be in surface contact, a heating part 3 is provided above the fixed plate BP, and a cooling part 4 is provided below the fixed plate BP. Then, by heating with the heating part 3 and cooling with the cooling part 4, an isotropic phase IP is formed at the upper part of the smectic liquid crystal S in the container 10, a liquid crystal phase SP is formed at the lower part, and an interface F is formed therebetween. When an object P is introduced into the smectic liquid crystal S from the upper part of the container 10 in this state, the object P sinks in the isotropic phase IP by gravity. Eventually, when the object P reaches the interface F, a force (hereinafter referred to as the penetration force FP) determined by the mass, gravity, volume, surface area, etc. of the object P is applied to the interface F. Then, if the penetration force FP is greater than the interfacial force of the interface F, the object P breaks through the interface F and penetrates into the liquid crystal phase SP (see FIG. 3(C)), and if the penetration force FP is greater than the interfacial force of the interface F, the object P will remain on the interface F (see FIG. 3(B)).

[0022] Therefore, by using the micromanipulator 1 of this embodiment, the object P can be retained at the position of the interface F or discharged below the interface F according to the object P. Further, by controlling the heating by the heating part 3 and the cooling by the cooling part 4 by the control part 5 of the interface generation means 2, the position of the interface F can be adjusted to hold the object P at a desired position (height) or move the object P to a desired position (height).

[0023] Moreover, in the micromanipulator 1 of this embodiment, since the smectic liquid crystal S is used, it is possible to prevent the object P from penetrating the interface F even when a relatively large penetration force FP is applied. For example, when 4-cyano-4’-dodecybiphenyl (12CB) is used as the smectic liquid crystal S, even when the specific gravity of the object P is extremely large (for example, microparticles with a density of 15.63 g / cm 3 or more), the holding and movement of the object P can be appropriately carried out.

[0024] <Regarding the moving member MP> As shown in FIG. 1, the micromanipulator 1 of the present embodiment may place the moving member MP on the smectic liquid crystal S and move the moving member MP.

[0025] This moving member MP is, for example, a flat plate or the like, but its shape and the like are not particularly limited. This moving member MP is disposed such that its contact surface (the lower surface in FIG. 1) contacts the smectic liquid crystal S, and moreover, it is held so that it can move along a predetermined moving direction while maintaining the state of contacting the smectic liquid crystal S. For example, in FIG. 2, the interface F described later moves in the left-right direction, and the moving member MP is also held so that it can move along the left-right direction while remaining in contact with the smectic liquid crystal S.

[0026] And, on the contact surface of the moving member MP, when it comes into contact with the smectic liquid crystal S in the liquid crystal phase SP state, a process of disturbing the state of the liquid crystal phase SP of the smectic liquid crystal S, that is, a process a of disturbing the orientation of the liquid crystal molecules in the liquid crystal phase SP (hereinafter referred to as the defect process a) is performed. For example, when it comes into contact with the smectic liquid crystal S in the liquid crystal phase SP state, a rubbing process such as a rubbing process that increases the energy of the molecular orientation field in the smectic liquid crystal S is performed. Specifically, vertical alignment processing, parallel alignment processing, or a composite processing thereof, etc. can be cited as the rubbing process.

[0027] Note that even if the moving member MP itself or the portion of the moving member MP that contacts the smectic liquid crystal S is made of a substance such that the energy of the molecular orientation field in the smectic liquid crystal S increases when it comes into contact with the smectic liquid crystal S in the liquid crystal phase SP state, the same effect can be obtained. For example, a process such as providing a layer of the above substance on the surface of the moving member MP may be performed. Examples of the substance such that the energy of the molecular orientation field in the smectic liquid crystal S increases when it comes into contact with the smectic liquid crystal S in the liquid crystal phase SP state include polystyrene and surfactants, etc., but are not particularly limited.

[0028] In particular, it is preferable that the defect treatment a is a treatment capable of forming a liquid crystal defect in the smectic liquid crystal S when it comes into contact with the smectic liquid crystal S in the liquid crystal phase SP state. In this case, when the moving member MP comes into contact with the liquid crystal phase SP, the disturbance formed in the liquid crystal phase SP becomes the largest, so that it becomes easier for the movement of the moving member MP to follow the movement of the interface F. Examples of the treatment capable of forming a liquid crystal defect include, but are not particularly limited to, a circular rubbing treatment using a rotating mechanism such as a motor.

[0029] <Procedure for moving the moving member MP> Next, a method for moving the moving member MP in the micromanipulator 1 of the present embodiment as described above will be described.

[0030] First, a part of the smectic liquid crystal S is heated to a temperature higher than the phase transition temperature Tc by the heating unit 3, and a part of the smectic liquid crystal S is cooled to a temperature lower than the phase transition temperature Tc by the cooling unit 4, so as to adjust the formation of the interface F in the smectic liquid crystal S. Then, the moving member MP is disposed on the liquid phase IP.

[0031] Next, the heating unit 3 and the cooling unit 4 are controlled so that the maximum temperature in the smectic liquid crystal S remains the same and the minimum temperature is decreased. In the case of FIG. 2(A), the temperature in the left region is decreased. Then, the temperature gradient in the smectic liquid crystal S becomes larger in its inclination, and the position where the phase transition temperature Tc is reached moves to the liquid phase IP side. Then, in the region of the liquid phase IP, as the position where the phase transition temperature Tc is reached moves, the interface F also moves to the liquid phase IP side.

[0032] When the interface F reaches the moving member MP (or the portion where the defect treatment a is performed on the moving member MP), the moving member MP moves together with the interface F (FIGS. 2(A) to (C)). That is, by adjusting the thermal energy applied to the smectic liquid crystal S and changing the temperature gradient Tg of the smectic liquid crystal S, in other words, by moving the interface F, the moving member MP in contact with the inside of the smectic liquid crystal S can be moved.

[0033] Therefore, in the micromanipulator 1 of the present embodiment, if a region of the liquid phase IP and a region of the liquid crystal phase SP are formed in the smectic liquid crystal S, and the temperature gradient Tg of the smectic liquid crystal S is changed to move the interface F toward the liquid phase IP, the moving member MP on the liquid phase IP can be moved together with the interface F along the moving direction of the interface F.

[0034] Moreover, in the micromanipulator 1 of the present embodiment, since the smectic liquid crystal S is used, even when the moving member MP has a large specific gravity (density 15.63 g / cm 3 or more), the moving member MP can be appropriately moved.

[0035] Note that the moving member MP does not necessarily have to be provided with the defect treatment a. Even if the defect treatment a is not provided, if the moving member MP and the interface F come into contact with each other, the moving member MP can be moved together with the interface F. However, if the above-described defect treatment a is performed on the moving member MP, the moving member MP can be effectively moved.

[0036] When the defect treatment a is performed on the moving member MP, the moving member MP can be effectively moved for the following reasons. In the liquid crystal phase SP, all liquid crystal molecules exist in an oriented state in a certain direction, while in the liquid, the molecules exist in a disordered state (isotropic state). Then, when the defect treatment a is performed on the moving member MP, in the system including the smectic liquid crystal S and the moving member MP, the moving body m exists in the liquid phase IP rather than the defect treatment a existing in the liquid crystal phase SP in the moving member MP, which results in a lower energy state. This is because the orientation of the liquid crystal molecules in the liquid crystal phase SP is disturbed by the defect treatment a. When the interface F moves from the liquid crystal phase SP side to the liquid phase IP side, the moving member MP tries to maintain the state of being in contact with the liquid phase IP so that no disturbance in orientation occurs in the liquid crystal phase SP due to the defect treatment a on the contact surface of the moving member MP that is in contact with the liquid phase IP. In other words, the moving member MP tries to maintain the state of being in contact with the liquid phase IP in order for the system including the smectic liquid crystal S and the moving member MP to maintain an energetically low state. Therefore, when the interface F moves from the liquid crystal phase SP side to the liquid phase IP side, if the moving member MP is subjected to the defect treatment a, the moving member MP can be effectively moved by the movement of the interface F.

[0037] In particular, it is preferable to provide a restraining means for restraining the orientation of the liquid crystal molecules when the smectic liquid crystal S becomes the liquid crystal phase SP, because the force for restraining the orientation of the liquid crystal molecules becomes stronger and the movement of the moving member MP accompanying the movement of the interface F is likely to occur.

Example

[0038] In the micromanipulator using the smectic liquid crystal of the present invention, it was experimentally confirmed that the interfacial force is large and the function of holding an object is high.

[0039] In the experiment, for the following three types of thermotropic liquid crystal materials, the interfacial forces were compared by dropping spherical particles onto the interface by gravity.

[0040] The three types of thermotropic liquid crystal materials used are shown below. Note that the density, viscosity, and phase transition temperature are the density, viscosity, and phase transition temperature of the smectic liquid crystal phase - isotropic phase in Example 1, the density, viscosity, and phase transition temperature of the nematic liquid crystal phase - smectic liquid crystal phase in Comparative Example 1, and the density, viscosity, and phase transition temperature of the nematic liquid crystal phase - isotropic phase in Comparative Example 2. <Example 1> 4-cyano-4’-dodecybiphenyl(12CB) Density: 1000kg / m 3Viscosity: 0.02 Pa·s Phase transition temperature: 58.5 °C <Comparative Example 1> 4-cyano-4’-octylbiphhenyl (8CB) Density: 989 kg / m 3 Viscosity: 0.10 Pa·s Phase transition temperature: 33.5 °C <Comparative Example 2> 4-cyano-4’-pentybiphhenyl (5CB) Density: 1008 kg / m 3 Viscosity: 0.023 Pa·s Phase transition temperature: 35.2 °C

[0041] The spherical particles used in the experiment are the following two spherical particles. 1) Polystyrene particles: Density 1.19 g / cm 3 Diameter 100 μm 2) Glass particles: Density 2.5 g / cm 3 Diameter 100 μm 3) Tungsten carbide particles: Density 15.93 g / cm 3 Diameter 100 μm

[0042] The experiment was carried out using the apparatus shown in Figure 4. As shown in Figure 4, a rectangular slide glass plate of 26 mm × 76 mm was arranged by a spacer so that the gap L between the rectangular slide glass plates was 188 μm, and each liquid crystal mixed with spherical particles was arranged in this gap to form an experimental cell. Note that a homeotropic anchor layer (JSR JALS-2021-R25: AL60101) was formed on the opposing surfaces of the rectangular slide glass plates by an anchor treatment. This experimental cell was sandwiched between a pair of highly conductive copper plates, a pair of upper highly conductive copper plates, and a pair of lower highly conductive copper plates. Peltier modules were attached to the pair of upper highly conductive copper plates and the pair of lower highly conductive copper plates, respectively. The temperature of this Peltier module was controlled with an accuracy of 0.03 K by a PID controller (Cell System Co., Ltd.: TDC 2010) to adjust the temperature distribution of the liquid crystal in the experimental cell, and a horizontal interface was made to appear in the liquid crystal in the cell.

[0043] The experiment was conducted in the following manner. First, the experimental cell was placed horizontally. That is, the experimental cell was arranged so that the surfaces of the pair of highly conductive copper plates were horizontal. In that state, the positions of the spherical particles mixed in the liquid crystal were kept constant. Next, the lower end temperature TU (hereinafter simply referred to as TU) of the pair of upper highly conductive copper plates and the upper end temperature TL (hereinafter simply referred to as TL) of the pair of lower highly conductive copper plates were once set to the temperature at which the temperature of the liquid crystal phase stabilizes, and then TL was made lower than the phase transition temperature, and the average of TU and TL was adjusted to be approximately equal to the phase transition temperature, causing an interface to appear in the middle of the experimental cell (the middle in the vertical direction in FIG. 4). After that, the posture of the experimental cell was changed vertically to let the spherical particles fall by gravity. That is, the experimental cell was arranged so that the surfaces of the pair of highly conductive copper plates were vertical, and the spherical particles were sedimented by gravity toward the interface. Then, the situation where the spherical particles sedimented by gravity toward the interface was photographed by a photographing device equipped with a video camera (IDS: UI-3360CP-C-HQ) and an objective lens (Nikon: 20X / 0.35) attached to a polarizing microscope. The photographed images were analyzed using image analysis software (ImageJ) to confirm the movement and displacement of the spherical particles and the interface.

[0044] The experimental results are shown below.

[0045] <Movement of Particles> The experimental results are shown in Fig. 5. In the image, the upper part is the isotropic phase or the nematic liquid crystal phase, the lower part is the smectic liquid crystal phase, and the part between the two is the interface. Also, the time when the bottom surface of the falling spherical particle apparently contacts the interface is defined as time t = 0 s.

[0046] Figs. 5(A) and (B) show the experimental results of Example 1 (12CB). Fig. 5(A) shows a time series of polarized light microscope images of tungsten particles sedimenting from the isotropic phase toward the smectic liquid crystal phase-isotropic phase interface when TU = 63.0 °C and TL = 53.5 °C, and Fig. 5(B) is a graph showing the change in the position of the tungsten particles and the smectic liquid crystal phase-isotropic phase interface when TU = 63.0 °C and TL = 53.5 °C.

[0047] As shown in Fig. 5(A), in Example 1 (12CB), the tungsten particles contact the smectic liquid crystal phase-isotropic interface at t = 0 s. Thereafter, although a distortion (dent) of the interface occurs at t > 1.2 s, it can be confirmed that the tungsten particles are held at the interface.

[0048] Also, as shown in Fig. 5(B), since the tungsten particles have a high density, they sediment rapidly and approach the interface quickly. However, it can be confirmed that despite the high terminal velocity of the tungsten particles, they are decelerated by the interfacial force of the interface. That is, it can be confirmed that the interface between the smectic liquid crystal phase and the isotropic phase has sufficient strength (interfacial force) to hold the tungsten particles colliding on the interface.

[0049] On the one hand, FIGS. 5(C) and (D) show the experimental results of Comparative Example 1 (8CB). Specifically, FIG. 5(C) shows a time series of polarized light microscope images in which polystyrene particles settle from the nematic liquid crystal phase toward the smectic liquid crystal phase-nematic liquid crystal phase interface when TU = 37.5 °C and TL = 28.0 °C, and FIG. 5(B) is a graph showing the change in the position of the polystyrene particles in the smectic liquid crystal phase-nematic liquid crystal phase when TU = 37.5 °C and TL = 28.0 °C.

[0050] As shown in FIGS. 5(C) and (D), in Comparative Example 1 (8CB), the polystyrene particles are in contact with the smectic liquid crystal phase-isotropic interface at t = 0 s. However, the speed of contact with the interface is smaller than that of the tungsten particles in Example 1. And at t = 81.9 s, it can be confirmed that the interface is broken by the polystyrene particles and the polystyrene particles penetrate the interface. That is, it can be confirmed that the smectic liquid crystal phase-nematic liquid crystal phase interface has no interfacial force that can hold even polystyrene particles with a smaller penetration force than the tungsten particles used in Example 1.

[0051] <Evaluation of interfacial force> The maximum value of the interfacial force acting on the spherical particles was evaluated.

[0052] Since the forces acting on the spherical particles at the interface are the interfacial force Fi, the gravitational force Fg, the buoyant force Fb, and the viscous drag force Fd, the motion equation of the particles can be expressed as in Equation 1. In the following equation, the symbols m and ν p are the mass and velocity of the particles. <Equation 1> mdν p / dt = Fi - Fg + Fb - Fd

[0053] Note that since the Reynolds number estimated from the falling speed and diameter of the spherical particles and the viscosity of the liquid crystal is small and Stokes' law can be applied to the viscous drag force, Equation 1 can be rewritten as Equation 2. ρ pwhere ρ₀ is the density of the particles, ρ is the density of the liquid crystal material, g is the acceleration due to gravity, d is the diameter of the particles, and μ is the viscosity of the liquid. <Equation 2> Fi = (ρ₀ p dν p / dt + (ρ₀ p − ρ)πd 3 ) / 6 + 3πdμν p

[0054] The velocity ν of the particles obtained by analyzing the images taken in the experiment (see FIGS. 5(A) and (C)) and the acceleration dν p of the particles and dν p / dt were substituted into this equation to obtain the interfacial force Fi. The velocity ν p of the particles and the acceleration dν p / dt of the particles were calculated by the Savitzky-Golay method using a cubic function from the data obtained by analyzing the image.

[0055] The evaluation of the interfacial force was performed using the velocity ν p of the particles and the acceleration dν p / dt obtained from the images of the experiment described above for Example 1, and for Comparative Example 1 and Comparative Example 2, the velocity ν p of the particles and the acceleration dν p / dt obtained from the images of the experiment using glass particles were used.

[0056] As a result, the interfacial force of Comparative Example 1 was 1.3 ± 0.1 nN, and the interfacial force of Comparative Example 2 was 5.5 ± 0.8 nN, while the interfacial force of Example 1 was 76.1 nN. It was confirmed that the interfacial force of the smectic liquid crystal phase-isotropic interface in Example 1 was significantly larger than the interfacial forces of Comparative Examples 1 and 2.

[0057] From the above results, it was confirmed that in the micromanipulator using smectic liquid crystal, the interfacial force of the smectic liquid crystal phase-isotropic interface is large, and the functions of moving and holding an object are high.

Industrial Applicability

[0058] The micromanipulator using the smectic liquid crystal of the present invention can be applied to a micromanipulator for moving minute objects.

Explanation of Signs

[0059] 1 Micromanipulator using smectic liquid crystal 2 Interface generation means 3 Heating section 4 Cooling section 10 Container S Smectic liquid crystal SP Smectic liquid crystal phase IP Isotropic phase F Interface EF Electric field

Claims

1. Smectic liquid crystals and and an interface generating means for generating an interface for holding an object between an isotropic phase in a liquid state and a liquid crystal phase in a liquid crystal state in the smectic liquid crystal.

3. A micromanipulator utilizing a smectic liquid crystal according to claim 2.

2. The interface generating means is It has the function of generating a liquid crystal phase in the upper part and an isotropic phase in the lower part.

2. A micromanipulator utilizing a smectic liquid crystal according to claim 1.

3. The interface generating means is The smectic liquid crystal has a function of moving the interface in the vertical direction.

3. A micromanipulator utilizing a smectic liquid crystal according to claim 2.

4. The smectic liquid crystal is 4-cyano-4'-dodecybiphenyl.

4. A micromanipulator utilizing a smectic liquid crystal according to claim 1, 2 or 3.

Images