CN110813926A - Oil stain surface self-cleaning device and method based on anti-electrowetting effect - Google Patents

Abstract

The invention discloses a self-cleaning device and method for oily surface based on reverse electro-wetting effect. The device includes: a self-cleaning environment device and a power supply that are connected by wires; wherein, the self-cleaning environment device includes: a fluid cavity, an oily environment The surface of the film, the dielectric material layer, the base metal and the low-conductivity fluid; the low-conductivity fluid is contained in the fluid chamber as the operating environment for the self-cleaning process of the oily film surface; the dielectric material layer is sprayed on the outer surface of the base metal to remove The base metal is completely wrapped; the surface of the oily film is closely attached to the outer surface of the dielectric material layer. The invention is based on the dielectric wetting effect. The surface of the oily film to be treated is placed in a low-conductivity fluid, and a liquid-liquid contact angle is formed on the surface of the oily film. Rapid increase, when the transient contact angle reaches 180 degrees, it will be separated from the surface of the oily film under the drive of dynamic energy, so as to realize the self-cleaning of the oily surface.

Description

A self-cleaning device and method for oily surface based on reverse electrowetting effect

technical field

The invention belongs to the technical field of fluid control and management, and in particular relates to a self-cleaning device and method for oily surfaces based on the reverse electrowetting effect.

Background technique

The self-cleaning of oil droplets or oil film on the surface of the film layer is a difficult problem. Many film surfaces have good lipophilicity. After contamination, the oil film is spread out and the contact angle formed is almost zero. Therefore, it is difficult to use conventional physical cleaning methods. Oil stains are completely rinsed off. Moreover, cleaning the film surface by external forces (such as physical rinsing, chemical reagent cleaning) will also bring many new problems. For example, the physical cleaning process is easy to destroy the film layer, and the chemical reagent method is easy to change the properties of the film surface. Therefore, traditional cleaning methods have great limitations on the surface of precious thin films or thin films with microstructures.

SUMMARY OF THE INVENTION

The technical solution of the present invention is to overcome the deficiencies of the prior art, and to provide a self-cleaning device and method for the oily surface based on the reverse electrowetting effect. In low-conductivity fluids, a liquid-liquid contact angle is formed on the surface of the oily film. By applying an external voltage, the contact angle on the oily film side increases rapidly. When the transient contact angle reaches 180 degrees, driven by dynamic energy It is separated from the surface of the oily film, so as to realize the self-cleaning of the oily surface.

In order to solve the above technical problems, the present invention discloses a self-cleaning device for oily surfaces based on the reverse electrowetting effect, including: a self-cleaning environment device connected by wires and a regulating power supply; wherein, the self-cleaning environment device includes: a fluid chamber , oily film surface, dielectric material layer, base metal and low conductivity fluid;

The low-conductivity fluid is contained in the fluid chamber as the operating environment for the self-cleaning process of the oily film surface;

The dielectric material layer is sprayed on the outer surface of the base metal to completely wrap the base metal;

The surface of the oily film is closely attached to the outer surface of the dielectric material layer.

In the above-mentioned self-cleaning device for oily surfaces based on the reverse electrowetting effect, it also includes: a positive terminal and a negative terminal;

The positive terminal is suspended in the low-conductivity fluid, and is connected to the output positive terminal of the regulating power supply through a wire;

The negative terminal is arranged on one side of the base metal, and is connected with the output negative terminal of the regulating power supply through a wire.

In the above-mentioned self-cleaning device for oily surfaces based on the reverse electrowetting effect, the device further comprises: a circuit breaker;

The disconnect switch is arranged on the wire for connecting the positive terminal and the output positive terminal of the regulated power supply.

In the above-mentioned self-cleaning device for oily surfaces based on the reverse electrowetting effect, the negative terminal and the wires placed in the low-conductivity fluid are both insulated and covered.

In the above-mentioned self-cleaning device based on the reverse electrowetting effect, the low-conductivity fluid and the oil film carried on the surface of the oily film are immiscible.

In the above-mentioned self-cleaning device for oil stained surfaces based on the reverse electrowetting effect, the density of the low-conductivity fluid is greater than the density of the oil film carried on the surface of the oil stained film.

In the above-mentioned self-cleaning device for oily surfaces based on the reverse electrowetting effect, it also includes: an AC power supply;

The AC power supply is connected to the input end of the regulating power supply, and outputs a DC adjustable voltage or an AC adjustable voltage through the output end of the regulating power supply.

In the above-mentioned self-cleaning device for oily surfaces based on the reverse electrowetting effect, the output voltage threshold V of the regulating power supply satisfies:

Among them, σ represents the interfacial tension between the oil film and the low-conductivity fluid, d represents the thickness of the dielectric material layer, ε represents the dielectric constant of the dielectric material layer, ε ₀ represents the vacuum dielectric constant, θ ₀ represents the oil film in the oil contamination The initial contact angle of the surface; C represents the dielectric strength of the electrical material layer.

In the above-mentioned self-cleaning device based on the reverse electrowetting effect, when the applied voltage on the surface of the oily film is greater than the output voltage threshold V, the rapid movement of the contact and the rapid increase in the contact angle cause the oil film on the surface of the oily film to shrink. Under the action of dynamic energy and inertia, the oil film completely shrinks into independent oil droplets and bounces on the surface of the film.

The invention also discloses a self-cleaning method for oily surfaces based on the reverse electrowetting effect, comprising:

Build self-cleaning environment devices;

Connect the self-cleaning environmental device to the regulated power supply through a wire;

Among them, the self-cleaning environment device is built through the following steps:

The low-conductivity fluid is contained in the fluid chamber as the operating environment for the self-cleaning process of the oily film surface;

Spray a dielectric material layer on the outer surface of the base metal to completely wrap the base metal;

The surface of the oily film is closely attached to the outer surface of the dielectric material layer, and placed together in a low-conductivity fluid.

The present invention has the following advantages:

(1) The present invention discloses a self-cleaning scheme of oily surface based on the reverse electrowetting effect. Based on the dielectric wetting effect, the surface of the oily film that needs to be treated is placed in a low-conductivity fluid. The surface of the film forms a liquid-liquid contact angle. By applying an external voltage, the contact angle on the oil film side increases rapidly. When the transient contact angle reaches 180 degrees, it will be separated from the surface of the oily film under the drive of dynamic energy, so that the surface of the oily surface will be detached. Self-cleaning.

(2) The present invention discloses a self-cleaning scheme for oily surfaces based on the reverse electrowetting effect, which has a simple structure and is easy to operate. It is also covered by insulating skin, which prevents the occurrence of electrolysis and oxidation on the surface of the positive and negative electrodes and the metal substrate, so that the reverse electrowetting process has good stability and sustainability.

(3) The present invention discloses a self-cleaning scheme for oily surfaces based on the reverse electrowetting effect, which can change the ion concentration and conductive characteristics of the environmental fluid by designing a reasonable low-conductivity fluid, so that the reverse electrowetting effect can be maximized The effective operating voltage can be minimized by selecting a reasonable dielectric material and coating thickness, and problems such as surface breakdown and dielectric effect failure can be avoided.

(4) The present invention discloses a self-cleaning scheme for oily surfaces based on the reverse electrowetting effect, which has a wide operation range. For oily types of different densities, viscosities and sizes, the interfacial tension can be changed by selecting a reasonable environmental fluid. and initial contact angle, so that the operating voltage is within a controllable range, and the cleaning process of oil pollution can be quickly completed.

Description of drawings

1 is a schematic structural diagram of a self-cleaning device for oily surfaces based on reverse electrowetting effect in an embodiment of the present invention;

2 is a schematic diagram of the implementation effect of the change in the shape of the oil film on the surface of the oily film surface and the detachment process after a voltage is applied in an embodiment of the present invention;

FIG. 3 is a schematic diagram of the implementation effect of the change in the initial contact angle of the oil film on the surface of an oily film in an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

Example 1

As shown in FIG. 1 , in this embodiment, the self-cleaning device for oily surfaces based on the anti-electrowetting effect includes: a self-cleaning environment device connected by a wire and a regulating power supply 9 . Wherein, the self-cleaning environment device includes: a fluid chamber 1 , an oily film surface 2 , a dielectric material layer 3 , a base metal 4 and a low-conductivity fluid 6 .

Preferably, the low-conductivity fluid 6 is contained in the fluid chamber 1 as a working environment fluid for the self-cleaning process of the oily film surface 2; the dielectric material layer 3 is sprayed on the outer surface of the base metal 4 to completely wrap the base metal 4; The film surface 2 is in close contact with the outer surface of the dielectric material layer 3 .

It can be seen that the present invention is based on the dielectric wetting effect. The surface of the oily film that needs to be treated is placed in a low-conductivity fluid to form a liquid-liquid contact angle on the surface of the oily film. The contact angle increases rapidly. When the transient contact angle reaches 180 degrees, it is separated from the surface of the oily film under the drive of dynamic energy, so that the surface of the oily surface is self-cleaning.

Example 2

As shown in FIG. 1 , the oily surface self-cleaning device based on the reverse electrowetting effect further includes: a positive terminal 7 and a negative terminal 8 . Among them, the positive terminal 7 is suspended in the low-conductivity fluid 6, and is connected to the output positive end of the regulating power supply 9 through a wire; The output negative terminal is connected.

Preferably, the negative terminal 8 and the lead wire placed in the low-conductivity fluid 6 are all insulated and covered, which prevents electrolysis and oxidation on the surface of the positive and negative electrodes and the metal substrate, so that the reverse electrowetting process has Very good stability and sustainability.

Preferably, a circuit breaker 11 is also provided on the wire used to connect the positive terminal 7 and the output positive terminal of the power supply 9, which can control the on-off of the self-cleaning device on the entire oily surface, and can be powered off in time when an abnormality occurs, which is safe and reliable. .

In a preferred embodiment of the present invention, the self-cleaning device for oily surfaces based on the reverse electrowetting effect may further include: an AC power source 10 . Wherein, the AC power source 10 is connected to the input end of the regulating power source 9 , and outputs a DC adjustable voltage or an AC adjustable voltage through the output end of the regulating power source 9 .

Preferably, in this embodiment, the output voltage required for adjusting the power supply 9 can be calculated by estimating the thickness of the oily surface, thereby determining the working range of the adjusting power supply 9 , that is, the output voltage threshold V of the adjusting power supply 9 .

Further preferably, the output voltage threshold V of the regulating power supply 9 can be determined in the following manner:

Among them, σ represents the interfacial tension between the oil film 5 and the low-conductivity fluid 6, d represents the thickness of the dielectric material layer 3, ε represents the dielectric constant of the dielectric material layer 3, ε ₀ represents the vacuum dielectric constant, θ ₀ represents the initial contact angle of the oil film 5 on the oil stained surface; C represents the dielectric strength of the electrical material layer 3 .

In this embodiment, as shown in FIG. 2 , when the voltage applied to the surface of the oily film 2 is greater than the output voltage threshold V, the rapid movement of the contact and the rapid increase in the contact angle cause the oil film 5 on the surface of the oily film 2 to shrink. And the inertial action makes the oil film 5 completely shrink into independent oil droplets, and bounce on the film surface.

Further, in this embodiment, the low-conductivity fluid 6 used is immiscible with the oil film 5 carried on the oil-stained film surface 2, and the density of the low-conductivity fluid 6 is greater than the density of the oil film 5 carried on the oil-stained film surface 2. Therefore, the oil droplets bouncing on the surface of the film can float to the surface of the low-conductivity fluid, avoiding secondary deposition on the oily surface, and improving the self-cleaning effect of the oily surface.

It should be noted that the low-conductivity fluid can be selected from ultrapure water, low-concentration salt solution or ionic liquid, etc., which is not limited in this embodiment. Correspondingly matched dielectric materials may be selected based on factors such as dielectric constant, dielectric strength, mechanical properties, and the like.

In summary, the present invention discloses a self-cleaning solution for oily surfaces based on the reverse electrowetting effect. Based on the dielectric wetting effect, the surface of the oily film that needs to be treated is placed in a low-conductivity fluid. A liquid-liquid contact angle is formed on the surface of the oily film. By applying an external voltage, the contact angle on the oily film side is rapidly increased. When the transient contact angle reaches 180 degrees, it is driven from the surface of the oily film by dynamic energy. Self-cleaning of surfaces. The structure is simple and the operation is convenient. The metal base layer is completely wrapped by the dielectric material. At the same time, the metal base layer and the wires in the ambient fluid are also covered by the insulating skin, which prevents electrolysis and oxidation on the surface of the positive and negative electrodes and the metal base. occurred, making the reverse electrowetting process with good stability and sustainability. Secondly, by designing a reasonable low-conductivity fluid, the ion concentration and conductivity characteristics of the ambient fluid can be changed, so that the anti-electrowetting effect can take place to the maximum extent; by choosing a reasonable dielectric material and coating thickness, it can maximize the Minimize the effective operating voltage and eliminate problems such as surface breakdown and dielectric effect failure. Thirdly, the self-cleaning scheme of the oily surface has a wide range of operation. For oily types of different densities, viscosities and sizes, the interphase interfacial tension and initial contact angle can be changed by selecting a reasonable environmental fluid to keep the operating voltage within a controllable range. , to quickly complete the cleaning process of oil stains.

Example 3

On the basis of the above embodiments, the present invention also discloses a method for self-cleaning oily surfaces based on the reverse electrowetting effect, including: building a self-cleaning environment device; Wherein, a self-cleaning environment device is built through the following steps: the low-conductivity fluid 6 is contained in the fluid chamber 1 as an operating environment for the self-cleaning process of the oily film surface 2; the outer surface of the base metal 4 is sprayed with a dielectric material layer 3, The base metal 4 is completely wrapped; the surface 2 of the oily film is closely attached to the outer surface of the dielectric material layer 3 and placed in the low-conductivity fluid 6 together.

In the present embodiment, the specific operation and realization principle of the self-cleaning scheme of the oily surface based on the reverse electrowetting effect to realize self-cleaning are as follows:

Clean the fluid chamber 1, attach the surface 2 of the oily film to be treated on the outside of the base metal 4 that has been coated with the dielectric material layer 3, and put them into the fluid chamber 1 together; The input end of 9 is connected to the conventional AC power supply 10, and the output end of the regulated power supply 9 is connected with the positive terminal 7 and the negative terminal 8 respectively through wires (can also be used regardless of positive and negative); Low-conductivity fluid 6 (low-conductivity fluid 6 is selected based on the following: the low-conductivity fluid 6 and the fluid of the oil film 5 being manipulated are immiscible, and the density of the low-conductivity fluid 6 is generally greater than that of the oily fluid 5, which can be Ultrapure water, low-concentration salt solution or ionic liquid and other fluids); after adding low-conductivity fluid 6, the contact angle of oil stains on the surface of the film changes, as shown in Figure 3, the contact angle of oil stains in the air environment is almost zero degrees, when After the insertion of the low-conductivity fluid 6, the contact angle increased significantly, which was due to the change of the surface energy between the three phases, and also brought convenience for the reverse electrowetting operation and oil cleaning; by calculating the required output voltage , determine the working range of the regulated power supply 9 (ie, the output voltage threshold V), and set the output voltage of the regulated power supply 9; wherein, the regulated power supply 9 can be a DC power supply or an AC power supply, and tests have shown that the AC power supply type can bring more significant The required operating threshold voltage is also lower than the voltage range under DC power supply conditions.

Turn on the regulating power supply 9, close the circuit breaker 11, the base metal surface layer is the negative electrode, the entire low-conductivity fluid becomes the positive electrode, and an instantaneous voltage is generated between the two, and the free electrons and ions in the base metal 4 and the low-conductivity fluid 6 are in the The two sides of the dielectric material layer 3 are redistributed, and the three-phase contact surface energy is changed (the reverse electrowetting phenomenon occurs near the liquid-liquid-solid phase contact line), so that the contact angle of the low conductive fluid 6 side decreases, while the oil film The contact angle on the 5 side increases.

When the voltage applied on the surface of the oily film is greater than the output voltage threshold V, the rapid movement of the contact and the rapid increase of the contact angle cause the oil film on the surface of the oily film to shrink, and the dynamic energy and inertia make the oil film completely shrink into independent oil droplets. and bouncing on the surface of the film. The density of the low-conductivity fluid is greater than that of the oil droplets, and the bounced oil droplets will float to the surface of the low-conductivity fluid to avoid secondary deposition on the oily surface and realize self-cleaning of the oily surface.

After the bouncing oil droplets float to the surface of the low-conductivity fluid 6, they can be removed by suction, and the operating range of the power supply 9 is continuously adjusted, and the on-off switch 11 is not turned off. Continuously cleaned to achieve active and complete self-cleaning.

As for the method embodiment, since it corresponds to the device embodiment, the description is relatively simple, and reference may be made to the description of the device embodiment part for the related parts.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can use the methods and technical contents disclosed above to improve the present invention without departing from the spirit and scope of the present invention. The technical solutions are subject to possible changes and modifications. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention belong to the technical solutions of the present invention. protected range.

Contents that are not described in detail in the specification of the present invention belong to the well-known technology of those skilled in the art.

Claims (10)

1. A self-cleaning device for oily surfaces based on anti-electrowetting effect, characterized in that it comprises: a self-cleaning environment device and a power supply (9) connected by wires; wherein, the self-cleaning environment device comprises: a fluid cavity (9). 1), oily film surface (2), dielectric material layer (3), base metal (4) and low conductivity fluid (6); The low-conductivity fluid (6) is contained in the fluid chamber (1) as an operating environment for the self-cleaning process of the oily film surface (2); The dielectric material layer (3) is sprayed on the outer surface of the base metal (4) to completely wrap the base metal (4); The oily film surface (2) is closely attached to the outer surface of the dielectric material layer (3). 2. The oily surface self-cleaning device based on the reverse electrowetting effect according to claim 1, characterized in that, further comprising: a positive terminal (7) and a negative terminal (8); The positive terminal (7) is suspended in the low-conductivity fluid (6), and is connected to the output positive end of the regulating power supply (9) through a wire; The negative terminal (8) is arranged on one side of the base metal (4), and is connected to the output negative terminal of the regulating power supply (9) through a wire. 3. The oily surface self-cleaning device based on the reverse electrowetting effect according to claim 2, characterized in that, further comprising: a circuit breaker (11); The disconnecting switch (11) is arranged on the wire for connecting the positive terminal (7) and the output positive terminal of the regulating power supply (9). 4. the oily surface self-cleaning device based on reverse electrowetting effect according to claim 2, is characterized in that, the negative terminal (8) and the wire that are placed in the low-conductivity fluid (6) all adopt insulating package overlay structure. 5. The self-cleaning device for oil stained surfaces based on the reverse electrowetting effect according to claim 1, wherein the low conductivity fluid (6) is immiscible with the oil film (5) carried on the oil stained film surface (2). 6. The oil-stained surface self-cleaning device based on the reverse electrowetting effect according to claim 1, wherein the density of the low-conductivity fluid (6) is greater than the density of the oil film (5) carried on the oil-stained film surface (2) . 7. The oily surface self-cleaning device based on the reverse electrowetting effect according to claim 1, characterized in that, further comprising: an alternating current power supply (10); The AC power supply (10) is connected to the input end of the regulating power supply (9), and outputs a DC adjustable voltage or an AC adjustable voltage through the output end of the regulating power supply (9). 8. The oily surface self-cleaning device based on the reverse electrowetting effect according to claim 1, characterized in that, the output voltage threshold V of the regulating power supply (9) satisfies:

where σ represents the interfacial tension between the oil film (5) and the low-conductivity fluid (6), d represents the thickness of the dielectric material layer (3), ε represents the dielectric constant of the dielectric material layer (3), ε ₀ represents the vacuum dielectric constant, θ ₀ represents the initial contact angle of the oil film (5) on the oily surface; C represents the dielectric strength of the electrical material layer (3). 9 . The oil-stained surface self-cleaning device based on the reverse electro-wetting effect according to claim 8 , wherein when the applied voltage on the oil-stained film surface (2) is greater than the output voltage threshold V, the rapid movement of the contact and the contact The rapid increase of the angle causes the oil film (5) on the oily film surface (2) to shrink, and under the action of dynamic energy and inertia, the oil film (5) completely shrinks into independent oil droplets and bounces on the film surface. 10. A self-cleaning method for oily surfaces based on reverse electrowetting effect, characterized in that, comprising: Build self-cleaning environment devices; Connect the self-cleaning environment device with the regulated power supply (9) through a wire; Among them, the self-cleaning environment device is built through the following steps: The low-conductivity fluid (6) is contained in the fluid chamber (1) as an operating environment for the self-cleaning process of the oily film surface (2); A dielectric material layer (3) is sprayed on the outer surface of the base metal (4) to completely wrap the base metal (4); The oily film surface (2) is closely attached to the outer surface of the dielectric material layer (3), and is placed in the low-conductivity fluid (6) together.

Images