Magnetically Controlled Liquid Driving Device with Lubricating Layer, Preparation Method and Application Thereof

Abstract

The present invention provides a magnetically controlled liquid driving device with a lubricating layer, which includes: a magnetically responsive composite interface channel, including: a base layer formed of a flexible material with a micro-nano structure and having a columnar hollow flexible channel, a columnar hollow lubricating layer disposed on the inner wall of the flexible channel for lubricating the conductive liquid, and a magnetic layer disposed on one outer wall of the base layer; a conductive liquid located in a cavity formed by the lubricating layer; and a magnet disposed opposite the magnetic layer across the base layer. The magnetically controlled liquid driving device with a lubricating layer provided by the present invention has low cost, fast response speed, continuous drive capability, convenient control, and a wide range of applications. It can control non-magnetic liquids using a magnetic field, and its movement speed and direction can be remotely controlled by an external magnetic field. Even if the magnetically responsive composite interface channel is slightly damaged, the conductive liquid can still pass through smoothly.

Description

Technical Field

[0001] The present invention relates to a magnetically controlled liquid driving device, a preparation method and an application thereof, and more particularly to a magnetically controlled liquid driving device with a lubricating layer, a preparation method and an application thereof. Background Art

[0002] Precisely manipulating liquid motion has broad industrial applications, such as in biomedical devices, liquid transport, and microfluidic systems. Currently, using magnetic forces to manipulate liquid motion has garnered significant research interest due to its advantages, including long-range action, high control force, and weak interaction between the magnetic field and the droplets. However, magnetic actuation is primarily used to transport magnetic fluids, limiting its scope of application.

[0003] Superhydrophobic surfaces are often used as carriers for manipulating liquids. However, their limited oleophobicity, high contact angle hysteresis, failure under pressure, and high production costs limit their application in liquid manipulation. Furthermore, damage to the carrier severely impairs liquid manipulation.

[0004] Therefore, it is very necessary to develop a driving device for magnetically controlled liquid movement that is low in cost, easy to operate, can magnetically control the transportation of non-magnetic fluids, and does not affect the use after damage. Summary of the Invention

[0005] In view of the above situation, the present invention invents a magnetically controlled liquid drive device with a lubricating layer, which includes: a magnetically responsive composite interface channel, including: a base layer formed of a flexible material with a micro-nano structure and having a columnar hollow flexible channel, a columnar hollow lubricating layer arranged on the inner wall of the flexible channel for lubricating the conductive liquid, and a magnetic layer arranged on the outer wall of one side of the base layer; the conductive liquid is located in the cavity formed by the lubricating layer; and a magnet is arranged opposite to the magnetic layer across the base layer.

[0006] The present invention also provides a method for preparing a magnetically controlled liquid driving device, comprising the following steps:

[0007] (1) Using a template method to prepare a cylindrical hollow substrate layer with a micro-nano structure on the inner surface: using an assembly with a micro-nano structure as a template, inserting it into a flexible material, and after the flexible material is shaped, removing the template to obtain a substrate layer with a micro-nano structure on the inner surface and a cylindrical hollow flexible channel;

[0008] (2) Arranging a magnetic layer on one side of the outer wall of the substrate layer: mixing magnetic nanoparticles with a flexible material prepolymer, coating the mixture on one side of the outer wall of the substrate layer, and then shaping the mixture to obtain a magnetic layer;

[0009] (3) Forming a lubricating layer on the inner wall of the flexible channel: a small amount of lubricating liquid is injected into the cavity of the base layer, and a lubricating layer is adsorbed on the inner wall of the cavity;

[0010] (4) injecting a conductive liquid into the cavity of the substrate layer;

[0011] (5) The magnetic layer is placed upward or downward, and the magnet is arranged opposite to the magnetic layer through the base layer, so that the movement of the conductive liquid in the cavity of the lubricating layer can be controlled.

[0012] The present invention also provides an application of a magnetically controlled liquid driving device, wherein the magnetically controlled liquid driving device is applied to the fields of energy, biotechnology, microsensors, or microfluidic control technology, and is used as a magnetically controlled liquid driving switch or a magnetically controlled liquid driving reaction container.

[0013] The magnetically controlled liquid driving device with a lubricating layer provided by the present invention has low cost, fast response speed, continuous drive, convenient control, and a wide range of applications. It can use a magnetic field to control non-magnetic liquid, and the movement speed and direction can be remotely controlled by an external magnetic field. Even if the magnetic response composite interface channel has minor damage, the conductive liquid can still pass through smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of a conductive liquid in an intact magnetically responsive composite interface channel;

[0015] Figure 2 Schematic diagram of the deformation of the magnetic layer in the intact magnetic responsive composite interface channel under the action of a magnetic field;

[0016] Figure 3 Schematic diagram of conductive liquid in a damaged magnetically responsive composite interface channel;

[0017] Figure 4 Schematic diagram of the deformation of the magnetic layer in a damaged magnetically responsive composite interface channel under the action of a magnetic field;

[0018] Figure 5 This is the circuit diagram of the magnetically controlled liquid driven switch;

[0019] Figure 6 This is an SEM image of a flexible material with micro-nanostructures according to an example of the present invention.

[0020] Description of Reference Numerals

[0021] 1 Flexible channel 2 Magnetic layer 3 Conductive liquid 4 Magnet 5 Small hole DETAILED DESCRIPTION

[0022] like Figure 1 and Figure 2As shown, the present invention provides a magnetically controlled liquid driving device with a lubricating layer, which includes: a magnetically responsive composite interface channel, including: a base layer (not shown) formed of a flexible material with a micro-nano structure and having a columnar hollow flexible channel 1, a columnar hollow lubricating layer (not shown) arranged on the inner wall of the flexible channel for lubricating a conductive liquid, and a magnetic layer 2 arranged on the outer wall of one side of the base layer; a conductive liquid 3 is located in a cavity formed by the lubricating layer; and a magnet 4 is arranged opposite to the magnetic layer across the base layer.

[0023] The flexible material with micro-nano structure has a rough surface, so the lubricating liquid can adhere to and spread well on the base layer formed by such flexible material. Therefore, the present invention has no particular limitation on the specific size of the micro-nano structure, as long as the lubricating liquid can adhere to and spread well on the base layer formed by such flexible material with micro-nano structure. For example, it can be a granular structure with a size of micron to nanometer, more specifically, it can be a granular structure with a size of micron to micron, micron to nanometer, or nanometer to nanometer. As an example of the present invention, Figure 6 As shown, from the SEM image of the flexible material with micro-nano structure, it can be seen that the micro-nano structure is a granular structure with an average particle size of about 5-10 microns.

[0024] The flexible material may be one or more of poly(dimethylsiloxane) (PDMS), Eco-flex, polyimide, epoxy resin, PET, silica gel, and SEBS, preferably Eco-flex, PDMS, and SEBS.

[0025] The present invention does not particularly limit the magnetic flux density of the magnet, as long as the magnetic flux density of the magnet is greater than 0 T and the magnetic flux density can deform the flexible channel into a wedge shape. In actual use, if the conductive liquid does not need to be moved, the magnet can be removed or the magnetic flux density can be reduced to 0.

[0026] In the present invention, the response time of the conductive liquid moving in the channel along the direction of movement of the magnetic field can be less than 0.1 s, which is a very fast response.

[0027] The conductive liquid and the lubricating layer in the channel are immiscible with each other.

[0028] The lubricating layer is formed in the cavity formed by the base layer by injecting lubricating liquid into the cavity.

[0029] Preferably, the lubricating layer is transparent so that the movement of the conductive liquid in the channel can be clearly seen.

[0030] Preferably, the lubricating liquid is a transparent organic oil having affinity with the flexible material, such as olive oil, silicone oil, etc.

[0031] Preferably, the conductive liquid is a conductive liquid that is immiscible with the lubricating liquid, such as an ionic liquid, a polyelectrolyte, a salt solution or water.

[0032] A small amount of liquid is injected into the channel. A magnetic field is placed on one side of the liquid and below the channel. The magnetic layer of the channel is attracted by the magnetic field and deforms, resulting in a wedge-shaped channel. The liquid then changes from a cylindrical shape to a wedge-shaped one, with the curvatures on the left and right sides being inconsistent. The resulting Laplace pressure difference causes the liquid to move toward the side with smaller curvature. Specifically, there is a pressure difference on both sides of the curved liquid surface. Under the action of surface tension, according to the Laplace equation, the additional pressure always points toward the center of curvature of the liquid surface. The magnetic field continues to move away from the liquid, and the liquid follows the movement of the magnetic field. When the magnetic field is removed, the channel returns to its original shape and the liquid stops moving.

[0033] The role of adding a lubricating layer: During the movement of liquid, it is subject to the resistance caused by the contact angle hysteresis and the driving force caused by the Laplace pressure difference. Due to the presence of a lubricating layer in the channel, the contact angle hysteresis is very small, so the driving force on the liquid is greater than the resistance, and the liquid can move smoothly under the control of the magnetic field.

[0034] Specifically, the channel is a type of liquid-infused surface (LIS). Inspired by the pitcher plant, the LIS surface consists of a micro-nanostructured substrate and a smooth, continuous atomic-level lubricant. LIS offers advantages such as reduced contact angle hysteresis, a smoother surface, a more stable structure, and lower fabrication costs. The lubricating layer also reduces resistance to liquid flow. Furthermore, even if the channel is damaged by a small gap (the gap should be small enough not to allow the conductive liquid to escape), the structure of the channel and the presence of the lubricating layer allow the liquid to be smoothly manipulated under the influence of a magnetic field.

[0035] Therefore, when the conductive liquid touches the two wires passing through the small hole at the same time, the circuit is connected and the appliance works; otherwise, the circuit is broken and the appliance does not work. When the magnetic field is removed, the channel returns to its original state and the conductive liquid stops moving.

[0036] The present invention also provides a method for preparing a magnetically controlled liquid driving device, which comprises the following steps:

[0037] (1) Using a template method to prepare a columnar hollow substrate layer with a micro-nanostructure on the inner surface: using an assembly with a micro-nanostructure as a template, inserting it into a flexible material, and after the flexible material is shaped, removing the template to obtain a substrate layer with a rough inner surface structure and columnar hollow flexible channels;

[0038] (2) Arranging a magnetic layer on one side of the outer wall of the substrate layer: mixing magnetic nanoparticles with a flexible material prepolymer, coating the mixture on one side of the outer wall of the substrate layer, and then shaping the mixture to obtain a magnetic layer;

[0039] (3) Forming a lubricating layer on the inner wall of the flexible channel: a small amount of lubricating liquid is injected into the cavity of the base layer, and a lubricating layer is adsorbed on the inner wall of the cavity;

[0040] (4) injecting the conductive liquid into the cavity formed by the lubricating layer;

[0041] (5) The magnetic layer is placed upward or downward, and the magnet is arranged opposite to the magnetic layer through the base layer, so that the movement of the conductive liquid in the cavity of the lubricating layer can be controlled.

[0042] The principle of the present invention is described below by taking an example where a magnet acts on the bottom of a magnetically responsive composite interface channel having a lubricating layer and is arranged opposite to the magnetic layer located above.

[0043] The part of the magnetic layer located in the upper half of the magnetically responsive composite interface channel that is most attracted by the magnetic field of the magnet is tightly attached to the base layer located on the opposite side of the magnetic layer, that is, the magnetically responsive composite interface channel becomes narrower. The Laplace pressure difference generated by the channel deformation causes the conductive liquid to move in the channel following the magnetic field.

[0044] Specifically, a pressure differential exists on either side of the curved liquid surface. Due to surface tension, and according to Laplace's equation, the additional pressure always points toward the center of curvature of the liquid surface. When the magnetic field is removed, the magnetically responsive composite interface channel returns to its original state. Even if the magnetically responsive composite interface channel is damaged with a small gap, the conductive liquid can still be smoothly manipulated due to the structure of the magnetically responsive composite interface channel and the presence of the lubricating layer.

[0045] Specifically, for example, Figure 3 and Figure 4 As shown, two small holes 5,5 are opened in the channel, and two non-contacting wires are passed through each of the holes. The holes can be located on the same side or on opposite sides. One wire is connected to a DC power supply, and the other to an electrical appliance. The electrical appliance and the DC power supply are connected by wires. A conductive liquid is injected into the channel, and a magnetic field is placed on one side of the conductive liquid. The magnetic layer of the channel is attracted by the magnetic field and deforms, resulting in a wedge-shaped channel. At this time, the conductive liquid also changes from a cylindrical shape to a wedge-shaped one, with the curvature of the left and right sides being inconsistent. The resulting Laplace pressure difference causes the liquid to move toward the side with smaller curvature. The conductive liquid follows the magnetic field and moves toward the two small holes. When the conductive liquid simultaneously contacts the two wires passing through the holes, the circuit is connected through the conductive liquid.

[0046] Take the magnetic liquid driven switch as an example, Figure 5As shown, in a circuit, the positive terminal of the DC power supply is connected to one end of the switch through a wire, and the other end of the switch is connected to the positive terminal of an electrical appliance (light bulb) through a wire; the negative terminal of the electrical appliance (light bulb) is connected to the negative terminal of the DC power supply through a wire, forming a loop.

[0047] like Figure 5 As shown in b, the conductive liquid moves with the magnetic field. When the conductive liquid moves to the point where it touches the two wires passing through the small holes at the same time, the wires between the small holes are electrically connected through the conductive liquid, and the light bulb lights up. Figure 5 a and Figure 5 As shown in Figure c, when the conductive liquid moves to the two wires that do not touch the small holes at the same time, the two wires cannot be electrically connected through the conductive liquid, and the light bulb goes out ( Figure 5 The two black dots in the figure represent two small holes. Thus, the magnetic liquid drive control switch is turned on and off.

[0048] Specifically, the magnetically responsive composite interface channel utilizes a type of liquid-infused surface (LIS) technology. Inspired by the pitcher plant, the LIS surface consists of a micro-nanostructured substrate and a smooth, continuous atomic-scale lubricant. LIS offers advantages such as reduced contact angle hysteresis, a smoother surface, a more stable structure, and lower fabrication costs. The lubricating layer also reduces the resistance to the conductive liquid's advance.

[0049] The magnetically controlled liquid driving device with a lubricating layer as described above can be applied to any field requiring a magnetically controlled liquid driving device, for example, in the fields of energy, biotechnology, microsensors, microfluidic control technology, etc.

[0050] Furthermore, the magnetically controlled liquid actuator with a lubricating layer described above can also be used as a magnetically controlled liquid-driven reaction vessel. For example, a small hole can be artificially damaged in the actuator channel. When the conductive reaction liquid follows the magnetic field to the hole, it reacts with substances outside the device through the hole. Specifically, for example, a small amount of methylene blue can be injected into the actuator. When it follows the magnetic field to the hole, a hydrochloric acid solution can be placed near the channel. The hydrochloric acid vaporizes into gas, enters the channel through the damaged hole, and interacts with the methylene blue in the channel. The reaction between the two causes the solution to turn from blue to red.

[0051] Therefore, the present invention also provides an application of a magnetically controlled liquid driving device, wherein the magnetically controlled liquid driving device is applied to the fields of energy, biotechnology, microsensors, or microfluidic control technology, and is used as a magnetically controlled liquid driving switch or a magnetically controlled liquid driving reaction container.

Claims

1. A magnetically controlled liquid drive device having a lubricating layer, characterized in that: include: A magnetically responsive composite interface channel comprises: a base layer formed of a flexible material having a micro-nano structure and having a columnar hollow flexible channel, a columnar hollow lubricating layer disposed on the inner wall of the flexible channel for lubricating a conductive liquid, and a magnetic layer disposed on one outer wall of the base layer; a conductive liquid located in the cavity formed by the lubricating layer; and The magnet is disposed opposite to the magnetic layer via the base layer.

2. The magnetically controlled liquid driving device according to claim 1, characterized in that: The micro-nano structure is a granular structure with a size from micrometer to nanometer.

3. The magnetically controlled liquid driving device according to claim 1, characterized in that: The flexible material is one or more of poly(dimethylsiloxane), Eco-flex, polyimide, epoxy resin, PET, silicone, and SEBS.

4. The magnetically controlled liquid driving device according to claim 1, characterized in that: The magnetic induction intensity of the magnet is greater than 0T and can deform the flexible channel into a wedge shape.

5. The magnetically controlled liquid driving device according to claim 1, characterized in that: The conductive liquid and the lubricating layer are incompatible with each other.

6. The magnetically controlled liquid driving device according to claim 1, characterized in that: The lubricating layer is formed in the cavity formed by the base layer by injecting lubricating liquid into the cavity.

7. The magnetically controlled liquid driving device according to claim 6, characterized in that: The lubricating liquid is an organic oil having affinity with the flexible material.

8. The magnetically controlled liquid driving device according to claim 1, characterized in that: The conductive liquid is an ionic liquid, a polyelectrolyte, a salt solution or water.

9. The method for preparing the magnetically controlled liquid driving device according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Using a template method to prepare a cylindrical hollow substrate layer with a micro-nano structure on the inner surface: using an assembly with a micro-nano structure as a template, inserting it into a flexible material, and after the flexible material is shaped, removing the template to obtain a substrate layer with a micro-nano structure on the inner surface and a cylindrical hollow flexible channel; (2) Arranging a magnetic layer on one side of the outer wall of the substrate layer: mixing magnetic nanoparticles with a flexible material prepolymer, coating the mixture on one side of the outer wall of the substrate layer, and then shaping the mixture to obtain a magnetic layer; (3) Forming a lubricating layer on the inner wall of the flexible channel: injecting lubricating liquid into the cavity of the base layer, and adsorbing it on the inner wall of the cavity to form a lubricating layer; (4) injecting the conductive liquid into the cavity formed by the lubricating layer; (5) The magnetic layer is placed upward or downward, and the magnet is arranged opposite to the magnetic layer through the base layer, so that the movement of the conductive liquid in the cavity of the lubricating layer can be controlled.

10. Use of the magnetically controlled liquid driving device according to any one of claims 1 to 8, characterized in that: The magnetically controlled liquid driving device is applied to the fields of energy, biotechnology, microsensors, or microfluidic control technology, and is used as a magnetically controlled liquid driving switch or a magnetically controlled liquid driving reaction container.

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