阅读说明：本技术 一种交流电渗驱动乙醇非对称型微泵及工作方法 (Alternating current electroosmosis driven ethanol asymmetric micropump and working method ) 是由 于泳 李凯 林海 于 2019-09-05 设计创作，主要内容包括：本发明实施例公开了一种交流电渗驱动乙醇非对称型微泵,包括第一金属电极和第二金属电极,以及微通道,所述第一金属电极上等间距阵列有大电极,第二金属电极上等间距阵列有小电极,大电极和小电极顺次交错阵列置于微通道中；其工作方法,包括步骤：加工该非对称型微泵,将非对称型微泵的大电极和小电极形成的阵列置于微通道内；向微通道内注入加了微量氢氧化钾电解质的乙醇溶液,将交流电正负极与第一金属电极和第二金属电极连接,施加交流电信号,驱动乙醇溶液流动,添加少量的KOH电解质,来代替通过在阳极金属电极材料,施加高电压产生阳离子,阳离子再注入到液体的方法,达到不损害电极的目的,延长微泵寿命,降低施加的电压,降低微泵功耗。(The embodiment of the invention discloses an alternating current electroosmosis driven asymmetric ethanol micropump, which comprises a first metal electrode, a second metal electrode and a microchannel, wherein the first metal electrode is provided with a large electrode in an equidistant array, the second metal electrode is provided with a small electrode in an equidistant array, and the large electrode and the small electrode are sequentially arranged in the microchannel in a staggered array; the working method comprises the following steps: processing the asymmetric micropump, and placing an array formed by a large electrode and a small electrode of the asymmetric micropump in a microchannel; the method comprises the steps of injecting ethanol solution added with trace potassium hydroxide electrolyte into a micro-channel, connecting an alternating current positive electrode and a alternating current negative electrode with a first metal electrode and a second metal electrode, applying an alternating current signal to drive the ethanol solution to flow, adding a small amount of KOH electrolyte to replace a method of applying high voltage to an anode metal electrode material to generate cations, and injecting the cations into liquid again, so that the purpose of not damaging the electrodes is achieved, the service life of the micro-pump is prolonged, the applied voltage is reduced, and the power consumption of the micro-pump is reduced.)

1. The alternating current electroosmosis driven ethanol asymmetric micropump is characterized by comprising a first metal electrode (1), a second metal electrode (2) and a microchannel (5), wherein the first metal electrode (1) and the second metal electrode (2) are arranged in mirror image opposition, large electrodes (3) are arranged on the first metal electrode (1) in an equidistant array, small electrodes (4) are arranged on the second metal electrode (2) in an equidistant array, and the large electrodes (3) and the small electrodes (4) are sequentially arranged in the microchannel (5) in a staggered array.

2. An AC electroosmosis driven asymmetric ethanol micropump according to claim 1, wherein the width ratio of the large electrode (3) to the small electrode (4) is 10:1, the width of the small electrode (4) is 10-30 μm, and the width of the large electrode (3) is 100-300 μm.

3. An electroosmosis-driven ethanol asymmetric micropump according to claim 2, wherein the large electrode (3) and the small electrode (4) are separated by 10-30 μm, and the electrode pair consisting of one large electrode (3) and one small electrode (4) is separated from the adjacent electrode pair by 30-300 μm.

4. An AC electroosmosis driven ethanol asymmetric micropump according to claim 2, wherein the material of the first metal electrode (1), the second metal electrode (2), the large electrode (3) and the small electrode (4) is the same and is any one metal of gold, platinum or copper.

5. An alternating current electroosmosis driving ethanol asymmetric micropump working method is characterized by comprising the following steps:

s100, processing the asymmetric micropump on silicon, glass or polymethyl methacrylate, and placing an array formed by a large electrode and a small electrode of the asymmetric micropump in a microchannel;

s200, injecting an ethanol solution added with trace potassium hydroxide electrolyte into the micro-channel, and adjusting the conductivity of the ethanol solution to be 5-110 uS/cm;

and S300, connecting the alternating current positive electrode and the alternating current negative electrode with the first metal electrode and the second metal electrode, applying an alternating current signal, and driving the ethanol solution to flow.

6. The AC electroosmosis driven asymmetric ethanol micropump and the operating method thereof according to claim 5, wherein in step S300, the AC voltage applied to the first metal electrode and the second metal electrode is 1-10V, and the AC frequency is 5-500 Hz.

Technical Field

The embodiment of the invention relates to the technical field of microfluidic systems, in particular to an alternating current electroosmosis driven ethanol asymmetric micropump and a working method.

Background

With the development of the performance and miniaturization of electronic components, the requirement for heat dissipation is higher and higher. The reliability of microelectronic devices is very sensitive to temperature, and the temperature rise of electronic devices can greatly reduce their reliability. The reliability of the device is reduced by 5% when the temperature of the device is increased by 1 ℃ at the level of 70-80 ℃. The development of future intellectualization requires that the CPU speed is increased by 2-3 orders of magnitude, and the existing air cooling technology cannot meet the heat dissipation requirement, so that a new liquid cooling technology needs to be developed. With the development of microfluidic systems, micropumps have become a key technology in microfluidic control and microelectronic cooling systems.

In a microfluidic system, a micro-flow driving and controlling technology of liquid is always a more critical technical problem. Control of microfluidics refers to control of fluids in systems or devices with feature sizes smaller than 1mm, and a driving technology for precise control of microfluidics is an inevitable requirement for the development of microfluidic systems. Therefore, microfluidic systems require the integration of controllable micropumps for pumping small volumes of microfluid, and the research of micropumps has become an important marker in the development of microfluidic systems.

The micropumps are structurally divided into mechanical micropumps and non-mechanical micropumps according to the operating principle, and the main difference between the mechanical micropumps and the non-mechanical micropumps is the presence or absence of moving parts. At present, mechanical micropumps mainly comprise: piezoelectric micropumps, electromagnetic micropumps, electrostatic micropumps, shape memory alloy micropumps, thermally driven micropumps and the like. The mechanical micropump has a long development history and a mature theory, can drive almost any type of liquid, and has the defects of easy friction generation, unstable pumping speed, micro leakage, short service life, difficult integration with a chip and the like in the micropump because of containing a moving part, and the reliability of the pump is greatly reduced. The non-mechanical micropump is a new direction for the research of the micropump.

The electroosmotic micro pump is the most important non-mechanical micro pump at present, and has the advantages of easiness in processing and control, no need of moving parts, high repeatability and reliability and the like. And can be classified into a dc electroosmosis driven micro pump and an ac electroosmosis driven micro pump according to the type of applied voltage. The direct current electroosmosis driving micropump has the advantages of adjustable flow, wide range, no piston, no valve, no dynamic seal, low manufacturing cost, simple design and the like, and is an effective liquid driving mode. The disadvantages are that high voltage and high direct current voltage (up to thousands of volts) are needed for the direct current electroosmosis fluid driving technology, potential safety hazards exist, electrolysis reaction is easy to occur to generate bubbles, a large amount of heat is generated, and the flowing stability of microfluid is further influenced. Because the voltage is very large and has certain harmfulness, the application range of the direct current electroosmosis pump is limited to a certain extent. Compared with the traditional direct current driving method, the alternating current driving method has the advantages of low applied voltage (the amplitude of the input signal voltage is generally less than 4V), capability of well inhibiting electrolytic reaction, easiness in integration with other micro devices and the like, so that the alternating current electroosmosis driving technology has important application value.

The driving liquid is mainly divided into aqueous solution and non-aqueous solution, the aqueous solution is widely applied in the biological field, and the liquid with the most extensive driving requirements in other fields is the non-aqueous solution, such as methanol, ethanol and the like, and is widely applied to systems such as micro fuel cells, chips, integrated circuits, electric appliance heat dissipation and the like. Only studies on alternating current electroosmosis driving aqueous solutions are conducted internationally, and no driving nonaqueous solutions are reported. At present, the method for driving the non-aqueous solution at home and abroad mainly adopts an injection type electro-hydraulic power pump, such as an ion drag pump.

The main principle is that a direct current high voltage is applied to an anode electrode to generate electrochemical reaction on the surface of the anode. The anode metal electrode material generates cations under the action of high voltage or the liquid generates ions through electrochemical reaction, and the ions are then injected into the liquid. The cations injected into the liquid are driven under the action of the electric field. Due to the action of the viscous forces, the energy of the cations is transferred to the fluid, causing the fluid to flow. This method has the advantage of being driven by substantially all solutions, including organic solutions that do not contain a charge, and has the disadvantage of consuming anode material at higher voltages, causing the micropump made by this method to fail very quickly.

At present, in a microfluidic system, the injection type electro-hydraulic power pump is adopted to drive a non-aqueous solution, so that the defects of high voltage, short service life and the like are caused, and a non-mechanical micropump cannot be applied to the microfluidic system in a large scale.

Disclosure of Invention

Therefore, the embodiment of the invention provides an alternating current electroosmosis driven asymmetric ethanol micropump and a working method thereof, the adopted alternating current electroosmosis driven asymmetric micropump has the advantages of low voltage, long service life and the like, the ethanol can be driven for a long time, and the defects of high voltage, short service life and the like of a non-aqueous solution driven by an injection type electro-hydraulic power pump and the like are overcome, so that the problem that the non-mechanical micropump cannot be applied to a microfluidic system in a large scale is caused.

In order to achieve the above object, an embodiment of the present invention provides the following:

an alternating current electroosmosis driving ethanol asymmetric micropump comprises a first metal electrode, a second metal electrode and a microchannel, wherein the first metal electrode and the second metal electrode are arranged in a mirror image opposite mode, a large electrode is arranged on the first metal electrode in an equidistant array, a small electrode is arranged on the second metal electrode in an equidistant array, and the large electrode and the small electrode are sequentially arranged in the microchannel in a staggered array.

In a preferred embodiment of the present invention, the ratio of the widths of the large electrode and the small electrode is 10:1, the width of the small electrode is 10 to 30 μm, and the width of the large electrode is 100 to 300 μm.

In a preferred embodiment of the present invention, the distance between the large electrode and the small electrode is 10 to 30 μm, and the distance between an electrode pair consisting of one large electrode and one small electrode and an adjacent electrode pair is 30 to 300 μm.

In a preferred embodiment of the present invention, the first metal electrode, the second metal electrode, the large electrode, and the small electrode are made of the same material and are made of any one of gold, platinum, and copper.

An alternating current electroosmosis driving ethanol asymmetric micropump working method is characterized by comprising the following steps:

s100, processing the asymmetric micropump on silicon, glass or polymethyl methacrylate, and placing an array formed by a large electrode and a small electrode of the asymmetric micropump in a microchannel;

s200, injecting an ethanol solution added with trace potassium hydroxide electrolyte into the micro-channel, and adjusting the conductivity of the ethanol solution to be 5-110 uS/cm;

and S300, connecting the alternating current positive electrode and the alternating current negative electrode with the first metal electrode and the second metal electrode, applying an alternating current signal, and driving the ethanol solution to flow.

In a preferred embodiment of the present invention, in step S300, the alternating current voltage applied to the first metal electrode and the second metal electrode is 1 to 10V, and the alternating current frequency is 5 to-500 Hz.

The embodiment of the invention has the following advantages:

the invention adds a small amount of KOH electrolyte in the ethanol solution, can drive the ethanol solution under lower voltage, and replaces the high voltage method adopted at present, the high voltage method mainly comprises the steps of applying high voltage to enable the anode metal electrode material to generate cations, the cations enter the liquid, and the cations in the liquid drive the solution under the action of an electric field.

And the microelectrode is designed into an asymmetric width, and then alternating current is applied to reduce the applied voltage and reduce the power consumption of the micropump.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions that the present invention can be implemented, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the effects and the achievable by the present invention, should still fall within the range that the technical contents disclosed in the present invention can cover.

Fig. 1 is a schematic structural view of an alternating current electroosmosis driven asymmetric ethanol micro-pump in embodiment 1 of the present invention;

fig. 2 is a diagram illustrating an experimental effect of an operation method of an alternating current electroosmosis driven asymmetric ethanol micro-pump in embodiment 2 of the present invention.

In the figure:

1-a first metal electrode; 2-a second metal electrode; 3-large electrode; 4-a small electrode; 5-micro-channel.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.