CN110270271A - A kind of preparation facilities of spherical liquid particle - Google Patents

Abstract

The present invention relates to new materials to research and develop field, a kind of preparation facilities of spherical liquid particle, including pedestal, hydrophobic substrate, voltage source, bracket, powder disk, camera, metal thin bar, syringe pump, displacement platform, ion wind gun, vibrating motor and cable, hydrophobic substrate is located at the upper surface of pedestal, hydrophobic substrate passes through cable connection voltage source, bracket is fixed on submounts, powder disk is connected to bracket by vibrating motor, so that powder disk is located at the top of hydrophobic substrate, metal thin bar is located at the top of powder disk, metal thin bar spatial vertical is in powder disk, the upper end of metal thin bar connects syringe pump, syringe pump is fixed below displacement platform, syringe pump includes fluid chamber and piston, piston moves downward can be transmitted to the upper end of metal thin bar by polar liquid and flow to the lower end of metal thin bar, ultimately form drop, it is thin that camera is located at metal At 10 centimetres of positions of bar side face z positive direction, ion wind gun is located at 15 centimetres of positions of powder disc side z negative direction.

Description

A preparation device for spherical liquid particles

technical field

The invention relates to the field of research and development of new materials, in particular to a preparation device for spherical liquid particles capable of preparing liquid droplets with a hydrophobic protective layer on the outer surface.

Background technique

The droplet with a hydrophobic protective layer on its outer surface is a recently developed new material structure, referred to as hydrophobic droplet, which has been used in biotechnology, pharmaceuticals and other fields. The hydrophobic layer on the surface of the hydrophobic droplet can protect the droplet and Avoiding contamination by the external environment, especially under relatively high external pressure, enables the droplet to maintain a spherical shape. In addition, the hydrophobic droplet is easier to manipulate, which plays an important role in some applications. Defects of the existing technology: the output of hydrophobic droplets is limited, and the size of the prepared droplets varies greatly, and there is a problem of contamination of the droplets during the preparation process, and the step of preparing hydrophobic droplets with a volume below the microliter level It is cumbersome and time-consuming, but the device for preparing spherical liquid particles can solve the problem.

Contents of the invention

In order to solve the above problems, the present invention generates submicroliter hydrophobic droplets based on the principle of electrofluid dragging, and vibrates the droplets deposited on the hydrophobic powder substrate to generate hydrophobic droplets of required size, and prepares Contamination of droplets can be avoided during the process.

The technical scheme adopted in the present invention is:

The device for preparing spherical liquid particles includes a base, a hydrophobic substrate, a voltage source, a support, a powder disk, a camera, a thin metal rod, a syringe pump, a displacement stage, an ion air gun, a vibration motor and cables, and xyz are three-dimensional coordinates The hydrophobic substrate is located on the base, and the hydrophobic substrate is connected to a voltage source through a cable. The voltage source can form a voltage difference between the hydrophobic substrate and the thin metal rod. The bracket is fixed on the base, and the powder disc is connected to the bracket through a vibration motor. , so that the powder disk is located above the hydrophobic substrate, the vibration motor can drive the powder disk to vibrate, and the position of the powder disk can be adjusted through the bracket. There is polytetrafluoroethylene PTFE powder in the powder disk, and the average size of the polytetrafluoroethylene PTFE powder particles is 300 microns, the thin metal rod is located above the powder plate, and the space of the thin metal rod is perpendicular to the powder plate. The upper end of the thin metal rod is connected to the syringe pump, and the syringe pump is fixed under the translation stage. The syringe pump and the thin metal rod can be made three-dimensional Moving, the syringe pump consists of a cylindrical liquid chamber and a piston with a polar liquid in the liquid chamber, and the downward movement of the piston can transmit the polar liquid to the upper end of the metal thin rod and flow along the metal thin rod to the lower end of the metal thin rod , finally forming droplets, the camera is located at the position of 10 cm in the positive z direction on the side of the thin metal rod, and the ion air gun is located at the position of 15 cm in the negative z direction on the side of the powder disk; the output voltage range of the voltage source is 0 to 4 kV; The hydrophobic substrate is made of a metal sheet; the powder disk is made of plastic and has a thickness of 6 mm; the thin metal rod has a diameter of 230 μm and a length of 1.3 mm; and the liquid chamber of the syringe pump has a diameter of 4 mm.

The steps for preparing hydrophobic droplets by using the preparation device for spherical liquid particles are as follows:

Step 1, adjust the position of the syringe pump and the thin metal rod through the displacement stage, so that the lower end of the thin metal rod is located at a position 11 cm directly above the hydrophobic substrate;

Step 2, adjust the position of the powder disk through the bracket, so that the powder disk is located at the position of 2 cm from the lower end of the thin metal rod;

Step 3, the plunger of the syringe pump moves downward at a speed of 10 μm/s, thereby generating liquid droplets at the lower end of the thin metal rod;

Step 4: Apply a DC voltage between the thin metal rod and the hydrophobic substrate through a voltage source, and the output voltage of the voltage source increases from 0 to 3 kV within 3 minutes to stretch the droplet at the lower end of the thin metal rod to The required volume will finally break away from the lower end of the thin metal rod, and the process of dropping the droplet will be monitored by a camera;

Step 5, the droplets dropped by the thin metal rod are collected by the powder disk, and the ion airflow emitted by the ion air gun is blown to the powder disk for 20 seconds, so that the charge of the droplets becomes neutral, which is conducive to the wrapping of the hydrophobic layer;

Step 6, turn on the vibration motor, so that the powder disk oscillates along the z direction, the frequency of the powder disk oscillation is 100 Hz, the oscillation amplitude is 600 microns, and lasts for 50 seconds;

Step 7, turn on the vibration motor, so that the powder disk oscillates along the x direction, the frequency of the powder disk oscillation is 100 Hz, the oscillation amplitude is 600 microns, and lasts for 50 seconds;

Step 8: Turn on the vibration motor to make the powder disk oscillate along the y direction. The frequency of the powder disk oscillation is 80 Hz and the oscillation amplitude is 300 microns for 30 seconds, so that the polytetrafluoroethylene PTFE powder is evenly wrapped on the outer surface of the droplet Thus, hydrophobic droplets are formed.

The beneficial effects of the present invention are:

The device of the present invention uses electric field assistance and multi-directional vibration to generate sub-microliter-level hydrophobic droplets. The preparation process does not require manual operation, the preparation speed is fast, the pollution to the droplets is small, and the volume distribution of the obtained hydrophobic droplets is relatively uniform.

Description of drawings

Below in conjunction with figure of the present invention further illustrate:

Figure 1 is a schematic diagram of the present invention.

In the figure, 1. Base, 2. Hydrophobic substrate, 3. Voltage source, 4. Support, 5. Powder disc, 6. Camera, 7. Metal thin rod, 8. Syringe pump, 9. Stage, 10. Ion Air gun, 11. Vibration motor.

Detailed ways

Figure 1 is a schematic diagram of the present invention, including a base (1), a hydrophobic substrate (2), a voltage source (3), a support (4), a powder tray (5), a camera (6), a thin metal rod (7), Syringe pump (8), translation stage (9), ion air gun (10), vibration motor (11) and cables, xyz is a three-dimensional coordinate system, hydrophobic substrate (2) is located on the top of base (1), hydrophobic substrate (2) Connect the voltage source (3) through a cable, the hydrophobic substrate (2) is made of a metal sheet, and the voltage source (3) can form a voltage difference between the hydrophobic substrate (2) and the thin metal rod (7) , the output voltage range of the voltage source (3) is 0 to 4 kV; the support (4) is fixed on the base (1), and the powder disc (5) is connected to the support (4) through the vibration motor (11), so that the powder disc (5) Located above the hydrophobic substrate (2), the vibration motor (11) can drive the powder pan (5) to vibrate, and the position of the powder pan (5) can be adjusted through the bracket (4). Tetrafluoroethylene PTFE powder, the average size of the polytetrafluoroethylene PTFE powder particles is 300 microns, the powder disk (5) is made of plastic, the thickness of the powder disk (5) is 6 mm, and the metal thin rod (7) is located in the powder disk Above (5), the metal thin rod (7) space is perpendicular to the powder disk (5), and the diameter of the metal thin rod (7) is 230 microns, and the length is 1.3 millimeters, and the upper end of the metal thin rod (7) is connected to the syringe pump ( 8), the syringe pump (8) is fixed under the displacement platform (9), and the syringe pump (8) and the thin metal rod (7) can be moved three-dimensionally through the displacement platform (9). The syringe pump (8) includes a cylindrical Liquid cavity and piston, the diameter of the liquid cavity of the syringe pump (8) is 4 mm, and there is a polar liquid in the liquid cavity, and the downward movement of the piston can transmit the polar liquid to the upper end of the metal thin rod (7), and along the metal thin rod (7) Rod (7) flows to the lower end of thin metal rod (7), finally forms droplet, and camera (6) is positioned at the 10 centimeter position of metal thin rod (7) side z positive direction, and ion wind gun (10) is positioned at powder disk ( 5) 15 centimeters in the negative direction of side z.

The device for preparing spherical liquid particles comprises a base (1), a hydrophobic substrate (2), a voltage source (3), a support (4), a powder disk (5), a camera (6), a thin metal rod (7 ), syringe pump (8), translation stage (9), ion air gun (10), vibration motor (11) and cables, xyz is a three-dimensional coordinate system, hydrophobic substrate (2) is located on the top of base (1), hydrophobic The substrate (2) is connected to a voltage source (3) through a cable, the voltage source (3) can form a voltage difference between the hydrophobic substrate (2) and the thin metal rod (7), and the bracket (4) is fixed to the base (1) Above, the powder disc (5) is connected to the support (4) through the vibration motor (11), so that the powder disc (5) is located above the hydrophobic substrate (2), and the vibration motor (11) can drive the powder disc (5) to vibrate, The position of the powder disc (5) can be adjusted by the bracket (4), there is polytetrafluoroethylene PTFE powder in the powder disc (5), the average size of the polytetrafluoroethylene PTFE powder particles is 300 microns, and the thin metal rod (7) is located at Above the powder disk (5), the space of the metal thin rod (7) is perpendicular to the powder disk (5), and the upper end of the metal thin rod (7) is connected to the syringe pump (8), and the syringe pump (8) is fixed on the translation stage (9) Next, the syringe pump (8) and the thin metal rod (7) can be moved three-dimensionally through the translation stage (9). The syringe pump (8) includes a cylindrical liquid chamber and a piston. There is a polar liquid in the liquid chamber, and the piston moves toward the The downward movement can transfer the polar liquid to the upper end of the thin metal rod (7), and flow along the thin metal rod (7) to the lower end of the thin metal rod (7), finally forming a droplet. The camera (6) is located on the thin metal rod ( 7) At a position of 10 cm in the positive direction of the side z, the ion air gun (10) is located at a position of 15 cm in the negative direction of the side z of the powder disk (5); the output voltage range of the voltage source (3) is 0 to 4 kV; The hydrophobic substrate (2) is made of a metal sheet; the powder disk (5) is made of plastic, the thickness of the powder disk (5) is 6 mm; the diameter of the metal thin rod (7) is 230 μm and the length is 1.3 mm ; The diameter of the liquid cavity of the syringe pump (8) is 4 millimeters.

The working principle of using a voltage to separate the droplet from the lower end of the metal thin rod (7) is: a constant voltage is applied between the metal thin rod (7) and the hydrophobic substrate (2) through the voltage source (3), so that the metal thin rod ( 7) An electrostatic field is generated between the hydrophobic substrate (2), and the droplet of the polar liquid is subjected to the downward electrostatic force, and the force balance is reached under the gravity of the droplet, that is, F _gravity + F _{electrostatic force} - F _{surface tension} =0, wherein the gravity F _gravity =(4πr ³ /3)ρg that droplet suffers, r is the radius of the droplet that hangs on metal thin rod (7) lower end, ρ is liquid density, and g is gravitational acceleration , the electrostatic force F on the droplet is _{electrostatic force} =ε ₀ SE ² /2, ε ₀ is the dielectric constant of the medium between the droplet surface and the hydrophobic substrate (2), and S is the lower end of the thin metal rod (7) The surface area of the droplet, E is the electric field strength between the droplet surface and the hydrophobic substrate (2), the surface tension F of the droplet _{surface tension} =2πRγ, γ is the surface tension constant of the liquid in the droplet, and R is the metal particle The outer radius of the lower end of the rod (7) shows that the F _gravity is a third-order function of the droplet radius, the F _{electrostatic force} is a second-order function of the droplet radius, and the F _{surface tension} is a first-order function of the droplet radius, which shows that the electrostatic force The effect of surface tension is greater for droplets of smaller size.

When the downward force on the droplet is greater than its surface tension, the suspended droplet will be separated from the lower end of the thin metal rod (7), and the electric field strength between the thin metal rod (7) and the hydrophobic substrate (2) will be greater , the smaller the radius when the droplet separates from the lower end of the thin metal rod (7), the smaller the electric field intensity at the lower end of the thin metal rod (7) and the size of the droplet hanging from the lower end of the thin metal rod (7) where V is the voltage applied by the voltage source (3) between the lower end of the thin metal rod (7) and the hydrophobic substrate (2), and D is the voltage between the lower end of the hydrophobic substrate (2) and the lower end of the thin metal rod (7). Distance, K=1.3 is the correction factor.

The powder disc (5) is located between the hydrophobic substrate (2) and the lower end of the metal thin rod (7), and the liquid droplet is separated from the lower end of the metal thin rod (7) and drips into the powder disc (5), and the powder disc (5) will Affect the electric field distribution between the lower end of the thin metal rod (7) and the hydrophobic substrate (2), thereby changing the electrostatic force, F _{electrostatic force} = ε ₀ S(EE ^/ ) ² /2, E ^/ is due to the powder disk (5) And the change of the electric field that causes, if the electric field intensity of the position of the lower end of the thin metal rod (7) and the electrostatic force applied to the droplet at the lower end of the thin metal rod (7) only depend on the applied voltage V, in this way, the liquid droplet is pulled The volume of the part leaving the lower end of the thin metal rod (7) is also a function of the voltage V, therefore, the relationship between the volume of the droplet leaving the lower end of the thin metal rod (7) and the applied voltage V can be obtained through experimental measurement.

In addition, the volume of the droplet at the lower end of the thin metal rod (7) is related to the flow rate and time of the liquid in the syringe pump (8). r _syringe is the diameter of the liquid cavity in the syringe pump (8), For the downward speed of the syringe pump (8) piston, v (t) is the volume of the droplet at the lower end of the metal thin rod (7), if the downward speed of the syringe pump (8) piston is constant, the metal thin rod ( 7) The relationship between the volume of the droplet at the lower end and time.

To sum up, the volume of the dropped liquid droplet can be controlled by the voltage between the thin metal rod (7) and the hydrophobic substrate (2).

The device of the present invention uses an electric field to assist droplets to drop and deposit on a hydrophobic powder substrate, and then vibrates it in multiple directions to generate hydrophobic droplets, which can generate submicroliter-level hydrophobic droplets without manual operation, and Contamination of droplets can be avoided.

Claims (6)

1. A preparation device for spherical liquid particles, comprising base (1), hydrophobic substrate (2), voltage source (3), support (4), powder disc (5), camera (6), thin metal rod ( 7), syringe pump (8), displacement stage (9), ion air gun (10), vibrating motor (11) and cable, xyz is a three-dimensional coordinate system, and it is characterized in that: hydrophobic substrate (2) is positioned at base (1 ), the hydrophobic substrate (2) is connected to the voltage source (3) through a cable, the voltage source (3) can form a voltage difference between the hydrophobic substrate (2) and the thin metal rod (7), and the bracket (4) is fixed On the base (1), the powder disk (5) is connected to the bracket (4) through the vibration motor (11), so that the powder disk (5) is located above the hydrophobic substrate (2), and the vibration motor (11) can drive the powder disk (5) Vibration, the position of the powder disc (5) can be adjusted by the support (4), there is polytetrafluoroethylene PTFE powder in the powder disc (5), the average size of the polytetrafluoroethylene PTFE powder particles is 300 microns, fine metal The rod (7) is located above the powder disc (5), the space of the metal thin rod (7) is perpendicular to the powder disc (5), the upper end of the metal thin rod (7) is connected to the syringe pump (8), and the syringe pump (8) is fixed on Below the translation stage (9), the syringe pump (8) and the thin metal rod (7) can move three-dimensionally through the translation stage (9). The syringe pump (8) includes a cylindrical liquid chamber and a piston. polar liquid, the downward movement of the piston can transfer the polar liquid to the upper end of the thin metal rod (7), and flow along the thin metal rod (7) to the lower end of the thin metal rod (7), finally forming droplets, the camera (6) Located at the position of 10 centimeters in the positive direction z of the side of the thin metal rod (7), the ion air gun (10) is located at the position of 15 centimeters in the negative direction of the side z of the powder disk (5). 2. A preparation device for spherical liquid particles according to claim 1, characterized in that: the output voltage range of the voltage source (3) is 0 to 4 kV. 3. A preparation device for spherical liquid particles as claimed in claim 1, characterized in that: the hydrophobic substrate (2) is made of a metal sheet. 4. A preparation device for spherical liquid particles as claimed in claim 1, characterized in that: the powder disk (5) is made of plastic, and the thickness of the powder disk (5) is 6 millimeters. 5. A preparation device for spherical liquid particles as claimed in claim 1, characterized in that: the thin metal rod (7) has a diameter of 230 microns and a length of 1.3 mm. 6. A preparation device for spherical liquid particles as claimed in claim 1, characterized in that: the diameter of the liquid cavity of the syringe pump (8) is 4 mm.