阅读说明：本技术 一种面向低表面能微滴定向输运与分离的结构及制备方法 (Structure for directional transportation and separation of low surface energy microdroplets and preparation method ) 是由 李国强 李耀霞 崔泽航 于 2021-01-13 设计创作，主要内容包括：本发明公开了一种面向低表面能微滴定向输运与分离的结构及制备方法,结构呈圆锥形刺状,表面具有圆形微坑阵列,均匀排布,可实现低表面能油滴逆重力自发快速从尖端运输到底端的功能,运输液滴表面张力范围为15 mN/m-48 mN/m,在这个范围内,表面张力越小,速度越快,最大运输速度可达265 mm/s,基于不同表面能液滴间的运输速度差,通过先将表面能较低的成分分离运输,再输送表面能较高液滴,实现不同表面张力的混合有机物液滴的分离,实现水-油、油-油等有机物混合微油滴的有效分离与定向输送,油滴分离与提纯为油污处理、矿油泄漏等环境问题提供新解决方法。(The invention discloses a structure for directionally conveying and separating low-surface-energy micro-droplets and a preparation method thereof, the structure is in a conical thorn shape, the surface is provided with a circular micro-pit array which is uniformly arranged, the function of spontaneously and rapidly conveying low-surface-energy oil droplets from a tip to a bottom against gravity can be realized, the surface tension range of the conveyed liquid droplets is 15 mN/m-48 mN/m, the smaller the surface tension is, the higher the speed is, the maximum conveying speed can reach 265 mm/s, based on the conveying speed difference among the liquid droplets with different surface energies, the effective separation and directional conveying of the mixed micro-droplets of water-oil, oil-oil and the like are realized by separating and conveying the liquid droplets with higher surface energy first and then conveying the mixed organic liquid droplets with different surface tensions, the separation and purification of the oil droplets are oil stain treatment, The environmental problems such as mineral oil leakage and the like provide a new solution.)

1. The utility model provides a structure towards directional transport of low surface energy droplet and separation, its characterized in that, the structure is conical thorn form, and the surface has the circular pit that is array evenly distributed, and the pit inner wall is the porous nanometer flocculent structure of random distribution, can realize that low surface energy oil droplet reverses the function that gravity spontaneous quick transport was from the prick pointed end to the bottom, and the transport liquid droplet surface tension scope is 15 mN/m-48 mN/m, and the maximum transport speed is 265 mm/s.

2. A low surface energy droplet directed transport and separation facing structure according to claim 1, wherein: the conical thorn-shaped structure is prepared by femtosecond laser processing, the diameter of a light spot of the laser is 20 microns, the pulse energy is 20mW, the scanning time is 25000 microns, and the distance between scanning lines is 25 microns.

3. A low surface energy droplet directed transport and separation facing structure according to claim 1, wherein: the diameter of the pits is 20-25 μm, the depth of the pits is 20-30 μm, and the center distance of the pits is 25-175 μm.

4. A low surface energy droplet directed transport and separation facing structure according to claim 1, wherein: the conical thorn structure is characterized in that the length of the conical thorn is 15-25 mm, and the vertex angle is 5-13 degrees.

5. The low surface energy droplet direct transport and separation facing structure of claim 4, wherein: the length of the conical thorn structure is 15mm, and the vertex angle is 5 degrees.

6. A method of preparing a low surface energy droplet oriented transport and separation structure according to claim 1 or 2, comprising the steps of:

s1, preparing a prick structure by using a precision 3D printing technology with the resolution of 10 mu m, wherein the material is light-cured resin;

s2, processing micro-pit arrays with the same spacing on the surface of the structure by femtosecond laser to obtain a conical burr structure with circular pits and a porous nano flocculent inner wall, wherein the incident direction of laser beams of the laser is vertical to the conical burr structure, and the laser beams perform parallel line scanning on the surface;

and S3, ultrasonically cleaning the conical spine processed in the step S2 for 5 minutes by using absolute ethyl alcohol with the concentration of 99.7 percent, and removing impurities to obtain a structure for directional transportation and separation of the microdroplets with low surface energy.

Technical Field

The invention relates to the field of material surface processing and liquid drop transportation, in particular to a structure for directionally transporting and separating low-surface-energy micro-drops and a preparation method thereof.

Background

The oil stains in air and water usually exist in the form of micro-droplets, and are difficult to separate and recover effectively due to small particles and high stability, so that the ecological environment and the human health are greatly harmed, and how to collect and separate the micro-droplets effectively and recycle the micro-droplets is an important problem which is concerned by environmental protection mechanisms and the oil and mineral industry. At present, reports about oil drop transportation and separation mainly focus on underwater transportation and liquid phase separation, droplet separation and selective transmission cannot be met, and meanwhile, the characteristics of complex preparation process, low transportation efficiency and the like exist. On the other hand, the micro-scale mixed liquid drops are not affected by phase separation, and the traditional separation method has great challenges in selective separation and directional transportation and collection of organic mixed micro-drops such as water-oil and oil-oil.

The automatic transportation of micro-droplets on a solid surface along a specific direction is generally determined by the microstructure and the chemical properties of the material surface, and has important research value and practical significance in industrial production and daily life, the problems of complicated preparation process, low transportation efficiency, incapability of realizing the separation of oil-oil and other organic matter mixed micro-droplets and the problems of complicated preparation process, low transportation efficiency, incapability of realizing the separation of oil-oil and other organic matter mixed micro-droplets exist, and therefore, a new idea and method are needed to solve the technical problems.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a structure for directional transportation and separation of low-surface-energy droplets and a preparation method thereof, which solve the problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a structure towards directional transport of low surface energy droplet and separation, the structure is conical thorn form, and the surface has the circular pit that is array evenly distributed, and the pit inner wall is the porous nanometer flocculent structure of random distribution, can realize that low surface energy oil droplet is against the function that gravity is spontaneous quick from the sharp-end transportation of awl to the bottom, and transportation liquid droplet surface tension range is 15 mN/m-48 mN/m, and the maximum transport speed is 265 mm/s.

Preferably, the conical thorn-shaped structure is prepared by femtosecond laser processing, the spot diameter of the laser is 20 μm, the pulse energy is 20mW, the scanning time is 25000 μ s, and the scanning line spacing is 25 μm.

Preferably, the diameter of each pit is 20-25 μm, the depth of each pit is 20-30 μm, and the center distance of each pit is 25-175 μm.

Preferably, the length of the conical spine structure is 15-25 mm, and the vertex angle is 5-13 degrees.

Preferably, the length of the conical spine structure is 15mm, and the vertex angle is 5 degrees.

A method for preparing a directional transportation and separation structure facing low surface energy droplets comprises the following steps:

s1, preparing a prick structure by using a precision 3D printing technology with the resolution of 10 mu m, wherein the material is light-cured resin and has oleophylic and hydrophobic properties;

s2, processing micro-pit arrays with the same spacing on the surface of the structure by femtosecond laser to obtain a conical burr structure with circular pits and a porous nano flocculent inner wall, wherein the incident direction of laser beams of the laser is vertical to the conical burr structure, and the laser beams perform parallel line scanning on the surface;

and S3, ultrasonically cleaning the conical spine processed in the step S2 for 5 minutes by using absolute ethyl alcohol with the concentration of 99.7 percent, and removing impurities to obtain a structure for directional transportation and separation of the microdroplets with low surface energy.

Preferably, the conical thorn structure in the step S1 has a conical thorn length of 15-25 mm and an apex angle of 5-13 degrees.

Preferably, the bur structure in step S1 has a bur length of 15mm and a vertex angle of 5 °

Preferably, the laser in step S2 has a spot diameter of 20 μm, a pulse energy of 20mW, a scanning time of 25000 μ S, and a scanning line pitch of 25 μm.

The invention has the beneficial effects that:

1. according to the invention, through researching the wettability form and the transport mechanism of the liquid drops on the surface of the unique composite conical thorn structure, the low-surface-energy liquid drops in a specific surface tension range are subjected to ultrahigh-gravity and ultra-fast spontaneous directional transport, the trend that the lower the surface energy is, the faster the transport speed is presented, the separation and selective transmission of multi-surface-tension mixed micro-drops are realized based on different liquid drop transport speed differences, and the effective separation and directional transport of organic matter mixed micro-drops such as water-oil and oil-oil are realized.

2. The invention has simple preparation, short operation time and high processing precision, can realize the spontaneous inverse gravity directional transportation of the liquid drops with low surface energy, the surface tension range of the transported liquid drops is 15 mN/m-48 mN/m, the smaller the surface tension in the range, the faster the speed, the maximum transportation speed can reach 265 mm/s, and the speed of realizing the underwater oil transportation in the prior known documents can reach 32.96 mm/s. Meanwhile, the separation of water-oil and oil-oil mixed liquid drops with different surface tensions can be realized based on the transportation speed difference among the liquid drops with different surface energies; 5 microliter of water-n-pentane mixed liquid drop separation time is 15.05 s; the separation time of 5 microliter of methanol-n-hexane organic mixed liquid drops is 25.17 s. The structure can be repeatedly used, and has important application value in the aspect of oil stain treatment.

Drawings

FIG. 1 is a schematic structural diagram of a low surface energy droplet directional transport and separation structure of the present invention, d is the distance between micro-pits;

FIG. 2 is a schematic cross-sectional view of a low surface energy droplet directional transport and separation structure of the present invention, with 2 α representing the angle of the tip of the stabbing structure;

FIG. 3 is an electron microscope image of the flocculent structure inside the pits of the low surface energy droplet directional transport and separation structure of the present invention;

FIG. 4 is a functional diagram of the transport of the low surface energy droplet orientation transport and separation structure of example 1 of the present invention;

FIG. 5 is a functional diagram of the oil-water separation of the structure for directional transport and separation of low surface energy droplets according to example 2 of the present invention;

FIG. 6 is a functional diagram of the separation of mixed organic droplets in the structure of low surface energy droplet orientation transport and separation according to example 3 of the present invention;

in the figure, 1 — the matrix structure; 2-pits; 3-pit center spacing; 4-pit flocculent structure.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.

Example 1

The structure for ultrafast directional transportation and selective separation of the low surface energy microdroplets is characterized in that the length of the conical thorn is 15mm, the vertex angle is 5 degrees, the material is light-cured resin, circular pits are uniformly distributed in an array form on the surface of the conical thorn, the inner walls of the pits are of porous nano flocculent structures which are randomly distributed, the diameter of each pit is 25 micrometers, the depth of each pit is 20 micrometers, and the center distance of each pit is 25 micrometers.

The preparation method of the micro-droplet directional transportation and separation structure with the low surface energy comprises the following steps:

s1, preparing a conical spine structure by using a precision 3D printing technology with the resolution of 10 mu m, wherein the material is light-cured resin, the length of the conical spine is 15mm, and the vertex angle is 5 degrees;

s2, processing micro-pit arrays with the same spacing on the surface of the structure by femtosecond laser to obtain a conical thorn structure with circular pits and a flocculent structure inside; the laser beam incidence direction of the laser is vertical to the conical spine, and the laser beam scans on the surface in parallel; the diameter of a laser spot is 20 microns, the pulse energy is 20mW, the scanning time is 25000 microns, and the scanning line spacing is 25 microns;

and S3, ultrasonically cleaning the machined conical spines for 5 minutes by using absolute ethyl alcohol with the concentration of 99.7%, and removing impurities.

In order to verify the effect of ultra-fast directional transport of low-surface-energy droplets and directional transport of droplets in a selective separation structure, 3 μ L of n-octane (surface tension 21.14 mN/m) was dropped through a needle onto the tip of a horizontally placed conical thorn structure, and the droplets were rapidly transported to the bottom at a speed of 265 mm/s.

Example 2

The structure for ultrafast directional transportation and selective separation of the low surface energy microdroplets is characterized in that the length of the conical thorn is 15mm, the vertex angle is 5 degrees, the material is light-cured resin, circular pits are uniformly distributed in an array form on the surface of the conical thorn, the inner walls of the pits are of porous nano flocculent structures which are randomly distributed, the diameter of each pit is 25 micrometers, the depth of each pit is 20 micrometers, and the center distance of each pit is 25 micrometers.

The preparation method of the micro-droplet directional transportation and separation structure with the low surface energy comprises the following steps:

s1, preparing a conical spine structure by using a precision 3D printing technology with the resolution of 10 mu m, wherein the material is light-cured resin, the length of the conical spine is 15mm, and the vertex angle is 5 degrees;

s2, processing micro-pit arrays with the same spacing on the surface of the structure by femtosecond laser to obtain a conical thorn structure with circular pits and a flocculent inner wall; the laser beam incidence direction of the laser is vertical to the conical spine, and the laser beam scans on the surface in parallel; the diameter of a laser spot is 20 microns, the pulse energy is 20mW, the scanning time is 25000 microns, and the scanning line spacing is 25 microns;

and S3, ultrasonically cleaning the machined conical spines for 5 minutes by using absolute ethyl alcohol with the concentration of 99.7%, and removing impurities.

In order to verify the effect of ultra-fast directional transport and selection of the separated water-in-oil mixed droplets of the separated structure by the low surface energy droplets, methylene blue is used for dyeing water, Sudan red III is used for dyeing n-pentane, a glass rod is used for mixing and stirring the two droplets to form a water-in-oil emulsion, a conical thorn structure is placed at an inclination angle of 10 degrees, a dropper is used for sucking 5 microliters of mixed solution, the mixed solution is dripped at the tip of the structure, red n-pentane is rapidly transported to the bottom end along the tip, blue water droplets are hemispherical and stay at the tip and then fall off, and the separation is finished within 15.05 s.

Example 3

The structure for ultrafast directional transportation and selective separation of the low surface energy microdroplets is characterized in that the length of the conical thorn is 15mm, the vertex angle is 5 degrees, the material is light-cured resin, circular pits are uniformly distributed in an array form on the surface of the conical thorn, the inner walls of the pits are of porous nano flocculent structures which are randomly distributed, the diameter of each pit is 25 micrometers, the depth of each pit is 20 micrometers, and the center distance of each pit is 25 micrometers.

The preparation method of the micro-droplet directional transportation and separation structure with the low surface energy comprises the following steps:

s1, preparing a conical spine structure by using a precision 3D printing technology with the resolution of 10 mu m, wherein the material is light-cured resin, the length of the conical spine is 15mm, and the vertex angle is 5 degrees;

s2, processing micro-pit arrays with the same spacing on the surface of the structure by femtosecond laser to obtain a conical thorn structure with circular pits and a flocculent inner wall; the laser beam incidence direction of the laser is vertical to the conical spine, and the laser beam scans on the surface of the surface in parallel; the diameter of a laser spot is 20 microns, the pulse energy is 20mW, the scanning time is 25000 microns, and the scanning line spacing is 25 microns;

and S3, ultrasonically cleaning the machined conical spines for 5 minutes by using absolute ethyl alcohol with the concentration of 99.7%, and removing impurities.

In order to verify the effect of ultra-fast directional transport of low-surface-energy droplets and separation of oil-oil mixed droplets with different surface tensions of a selective separation structure, methylene blue dyes methanol, n-hexane does not dye, two organic liquids are stirred into a mixed solution by a glass rod, a conical thorn structure is inclined by 10 degrees, 5 microliters of the mixed solution is sucked by a dropper and is dripped at the tip of the structure, colorless n-hexane is rapidly transported to the bottom end along the tip before blue methanol, and finally blue methanol is gradually transported to the bottom end along the tip gradually, and separation is finished within 25.17 s.

Fig. 1, fig. 2 and fig. 3 are a schematic structural, sectional view and an electron microscope image of a flocculent structure inside a pit, respectively, of a directional transport and selective separation structure, d in fig. 1 is a distance between micro pits, and 2 α in fig. 2 is an included angle of a tip of a conical thorn structure.

Comparative example 1

Based on example 1, the pit pitches were 75 μm, 125 μm, 175 μm, and the surface not processed by laser, respectively. Other conditions were unchanged.

Comparative example 2

Based on example 1, the conical burr structure was placed at an inclination angle of 10 ° and 20 °, respectively, for experimental comparison. Other conditions were unchanged.

Through the verification of the above example 1 and comparative examples 1-2, the example 1 can realize the ultra-fast transportation of the low surface energy liquid drop with the speed of 265 mm/s, while the comparative examples 1-2 can not achieve the effect of the example 1 of the invention, and the transportation speed of the same liquid drop in the comparative example is slower.

FIG. 4 is a schematic diagram of transportation of n-octane when the inclination angle of the prick structure with the pit pitch of 25 μm is 10 degrees in example 1, FIG. 5 is a schematic diagram of separation process of a mixed liquid of n-pentane and water when the inclination angle of the prick structure with the pit pitch of 25 μm is 10 degrees in example 2, FIG. 6 is a schematic diagram of separation process of a mixed liquid drop of methanol and n-hexane when the inclination angle of the prick structure with the pit pitch of 25 μm is 10 degrees in example 3, and a series of comparative experiments show that the effect of horizontally placing and transporting the liquid drop is the best when the pit is 25 μm and the apex angle is 5 degrees, and meanwhile, the lower the surface tension of the liquid drop is within the range of transportation surface tension (15 mN/m-48 mN/m), the faster the transportation speed is, the preparation of the invention is simple, the operation time is short, the processing precision is high, and the spontaneous antigravity directional transportation of the liquid drop, the surface tension range of transported liquid drops is 15 mN/m-48 mN/m, in the range, the smaller the surface tension, the faster the speed, the maximum transportation speed can reach 265 mm/s, and the speed for realizing underwater oil transportation in the currently known literature reaches 32.96 mm/s. Meanwhile, the separation of water-oil and oil-oil mixed liquid drops with different surface tensions can be realized based on the transportation speed difference among the liquid drops with different surface energies; 5 microliter of water-n-pentane mixed liquid drop separation time is 15.05 s; the separation time of 5 microliter methanol-n-hexane organic mixed liquid drops is 25.17s, and the structure can be recycled, so that the method has an important application value in the aspect of oil stain treatment.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.