Assembled asymmetric smooth track as well as preparation method and application thereof

Abstract

The invention discloses an asymmetrical smooth track capable of being assembled as well as a preparation method and application of the asymmetrical smooth track. The assembly form is one of a single track, a double track, a three track, a modular track I and a modular track II. The preparation method comprises the following steps: respectively polishing a bar and a substrate by abrasive paper; the bar and the substrate are soaked in a silicon dioxide super-hydrophobic solution respectively, taken out after being wetted, and cured for 1-3 h at the temperature of 60-80 DEG C after a solvent is completely volatilized; the bar and the substrate are soaked in simethicone with the viscosity being 2-20 cst respectively, the bar and the substrate are taken out after being wetted, and redundant simethicone is removed; and the bar and the base are assembled according to the assembly form. The asymmetrical smooth track capable of being assembled is applied to self-transportation of micro-droplets or bubbles. According to the assembled asymmetric smooth track constructed by the invention, the wetting ridges around the micro-droplets or bubbles in the asymmetric smooth track and asymmetric deformation generated by the micro-droplets or bubbles are used as driving force for self-transportation of the micro-droplets or bubbles at the same time, so that self-transportation of the micro-droplets or bubbles can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of controllable self-transport of micro-droplets or bubbles, and in particular relates to an assembleable asymmetric smooth track and a preparation method and application thereof. Background Art

[0002] The transport of microdroplets or bubbles on the surface of asymmetric structures has always been the most basic research. Realizing the self-transport of microdroplets or bubbles can effectively reduce the energy consumption in the process of driving the transport of microdroplets or bubbles. At present, based on the principle of bionics, asymmetric structures inspired by cactus spines, spider silk and bird beaks are used to drive the self-transport of microdroplets or bubbles by using the Laplace pressure difference generated by the asymmetric structure. However, due to the asymmetry of its structure, the direction of the self-transport of microdroplets or bubbles on its surface is limited and often cannot be changed; the displacement and speed of the self-transport of microdroplets or bubbles on its surface are extremely small; the shape of the asymmetric structure after processing cannot be flexibly adjusted as needed; and it is difficult for the microdroplets or bubbles on its surface to achieve more complex and flexible movement and manipulation. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide an assembleable asymmetric smooth track and a preparation method and application thereof.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows: An asymmetric smooth track can be assembled, wherein the assembly form of the asymmetric smooth track is one of the following single track, double track, triple track, modular track I, and modular track II: (1) Single track: includes a base and two rods located thereon, the two rods are directly placed or fixed on the base in a "small V shape", and the two rods intersect or do not intersect at the narrow end of the "small V shape"; the angle of the "small V shape" is α; (2) Double track: It includes a base and four rods located thereon, wherein two rods form a group and one end of the two rods are intersected and fixed together in a "large V shape", with a total of two groups of "large V shapes"; the narrow ends of the two groups of "large V shapes" are directly placed or fixed on the base in a manner of being spaced and facing each other; the angle of the "large V shape" is 180°-α; (3) Three tracks: including a base and six rods located thereon, wherein two rods form a group and one end of the two rods intersect and are fixed together in a "large V' shape", with a total of three groups of "large V' shapes"; the narrow ends of the three groups of "large V' shapes" are directly placed or fixed on the base in the form of three vertex positions of an equilateral triangle; the angle of the "large V' shape" is 120°-α; (4) Modular track I: including module 1, module 2 and module 3. Module 1 and module 3 have the same structure. Module 1 and module 2 are cut vertically downward from the same single track in (1). Module 1 is the narrow end of the single track, and module 2 is the wide end of the single track. Module 1 and module 2 are placed together and the wide end of module 1 is connected to the narrow end of module 2. Module 3 is placed independently of module 1 and module 2. (5) Modular track II: including module 1', module 2' and module 3'. Module 1' and module 3' are symmetrical structures with respect to the vertical plane. Module 2' and module 3' are cut vertically downward from the same single track in (1). Module 3' is the narrow end of the single track, and module 2' is the wide end of the single track. Module 1' and module 2' are placed together and the narrow end of module 1' is connected to the narrow end of module 2'. Module 3' is placed independently of module 1' and module 2'. The degree of α is 3-9°; the surfaces of the rod and the substrate are both provided with a silicon dioxide super-hydrophobic coating, and the surface of the silicon dioxide super-hydrophobic coating is provided with a dimethyl silicone oil layer.

[0005] Preferably, the shape of the base is rectangular or circular; the shape of the rod is a cylinder, a semi-cylinder, an isosceles right triangular prism or a right quadrangular prism; when the rod is a semi-cylinder, the side where the plane of the semi-cylinder is located is directly placed or fixed on the base; when the rod is an isosceles right triangular prism, the side where the hypotenuse of the isosceles right triangular prism is located is directly placed or fixed on the base; when the rod is a right quadrangular prism, any side of the right quadrangular prism is directly placed or fixed on the base.

[0006] Preferably, the material of the substrate is ABS or Cu; the material of the rod is ABS, Cu or PMMA.

[0007] Preferably, all the fixing methods involved are adhesive fixings.

[0008] The preparation method of the asymmetric smooth track is as follows: S1. Use sandpaper to polish the entire outer surface of the rod and the base, and rinse them with water; S2, immersing the rod and substrate obtained in step S1 in a silicon dioxide super-phobic solution, taking them out after wetting, and waiting for the solvent to evaporate completely; S3, curing the rod and the substrate obtained in step S2 at 60-80° C. for 1-3 hours respectively; S4, immersing the rod and the substrate obtained in step S3 in dimethyl silicone oil with a viscosity of 2-20 cst respectively, taking them out after wetting, and placing them vertically to remove excess dimethyl silicone oil; S5. Assemble the rod obtained in step S4 and the base according to one of the assembly forms (1) to (5) to obtain the corresponding asymmetric super-smooth track.

[0009] Preferably, the silica super-hydrophobic aqueous solution is composed of PDMS: curing agent: n-hexane: super-hydrophobic silica nanoparticles = (9-11): (0.9-1.1): (17-28): (6-10) in terms of mass ratio, and the curing agent is a curing agent used in conjunction with PDMS.

[0010] Preferably, the surface water drop contact angle of the superhydrophobic silica nanoparticles is greater than 150°.

[0011] Preferably, the sandpaper is 400-2000 grit sandpaper.

[0012] The application of the assembleable asymmetric smooth track in microdroplet self-transportation includes but is not limited to the application in microdroplet manipulation, microdroplet reaction, microdroplet merging, microdroplet splitting, microdroplet detection, and microdroplet nanogenerator.

[0013] The application of the assembleable asymmetric smooth track in the self-transportation of bubbles in water includes but is not limited to the collection or reaction of bubbles in water.

[0014] Beneficial effects: (1) Introducing a silica super-hydrophobic coating, utilizing the rough nanostructure and hydrophobic and oleophilic properties of the silica super-hydrophobic coating surface, low-viscosity dimethyl silicone oil can be injected onto its surface and stably stored on the surface of the asymmetric track that can be assembled; (2) The dimethyl silicone oil injected into the surface of the asymmetric smooth track provides wetting ridges that generate driving force for the self-transport of microdroplets or bubbles; (3) The asymmetric smooth track constructed by the present invention can be assembled, and the wetting ridges around the micro-droplets or bubbles in the asymmetric smooth track and the asymmetric deformation of the micro-droplets or bubbles themselves are used as the driving force for the self-transport of the micro-droplets or bubbles at the same time, so that the self-transport of the micro-droplets or bubbles in two different directions can be realized: when the asymmetric driving force generated by the wetting ridges is greater than the asymmetric driving force generated by the deformation of the micro-droplets or bubbles, the self-transport direction of the micro-droplets or bubbles in the asymmetric smooth track is transported from the wide end to the narrow end; when the asymmetric driving force generated by the wetting ridges is less than the driving force generated by the deformation of the micro-droplets or bubbles, the self-transport direction of the micro-droplets or bubbles in the asymmetric smooth track is transported from the narrow end to the wide end; (4) The present invention can be equipped with an asymmetric smooth track, and the displacement and speed of the self-transport of micro-droplets or bubbles on its surface are relatively large; (5) The asymmetric smooth track of the present invention can be designed as a double track or even a triple track, so as to achieve more flexible applications for the merging, reaction and detection of micro-droplets or bubbles; (6) The asymmetric smooth track of the present invention can be designed to be modular, and the interaction of each module can be used to achieve more flexible micro-droplet or bubble movement and application, such as merging and transferring of micro-droplets or bubbles, splitting and transferring of micro-droplets or bubbles. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : One of the top views of an asymmetric smooth track with a single track assembly form; Figure 2 : One of the side views of an asymmetric smooth track with a single track assembly form; Figure 3 : Schematic diagram of the self-transport of micro-droplets in an asymmetric smooth track with a single track as the assembly form; Figure 4 : A top view of an asymmetric smooth track with double tracks as the assembly form; Figure 5 : A top view of an asymmetric smooth track with three tracks as the assembly form; Figure 6 : A top view of an asymmetric smooth track with modular track I as the assembly form; Figure 7 : A top view of an asymmetric smooth track in the form of a modular track II; Figure 8 : The second side view of the asymmetric smooth track with a single track as the assembly form; Fig. 9 : The second top view of the asymmetric smooth track with a single track as the assembly form; The figures are marked as follows: 1 - base; 2 - rod. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the described embodiments, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present invention.

[0017] The PDMS and curing agent used in the following examples are matching products purchased from Dow Corning Corporation of the United States, model number SYLGARD184.

[0018] Micro droplet example Example 1 - Single track like Figure 1~2As shown, an asymmetric smooth track that can be assembled is in the form of a single track, including a substrate 1 and two rods 2 located thereon, the two rods 2 are directly placed on the substrate 1 in a "small V shape", and the two rods 2 intersect at the narrow end of the "small V shape"; the angle of the "small V shape" is 3°; the surfaces of the rods 2 and the substrate 1 are both provided with a silicon dioxide super-hydrophobic coating, and the surface of the silicon dioxide super-hydrophobic coating is provided with a dimethyl silicone oil layer; the substrate 1 is a rectangular ABS sheet with a length of 100 mm, a width of 25 mm, and a thickness of 0.5 mm; the rod 2 is an ABS cylinder with a length of 100 mm and a diameter of 3 mm.

[0019] The preparation method of the above-mentioned asymmetric smooth track is as follows: S1, pretreatment: polish the entire outer surface of the two rods 2 and the substrate 1 with 2000 grit sandpaper, and rinse with deionized water; S2, super-hydrophobic modification: immerse the two rods 2 and the substrate 1 obtained in step S1 in a super-hydrophobic silica solution for 1 second, take them out, and wait for the solvent to evaporate completely; in terms of mass ratio, the super-hydrophobic silica solution is composed of PDMS: curing agent: n-hexane: super-hydrophobic silica nanoparticles (surface water droplet contact angle greater than 150°) = 10:1:21:8; S3, curing: the two rods 2 and the substrate 1 obtained in step S2 are placed in an oven at 80° C. and cured for 2 h; S4, oil layer injection: The two rods 2 and the substrate 1 obtained in step S3 are immersed in dimethyl silicone oil with a viscosity of 2 cst respectively, taken out after wetting, and placed vertically for 10 seconds to remove excess dimethyl silicone oil; S5, assembly: Place the two rods 2 obtained in step S4 on the base 1 at an angle of 3° to obtain the corresponding asymmetric super-smooth track.

[0020] like Figure 3 As shown, the application of the above-mentioned asymmetric smooth track can be assembled: 20 microliters of water is dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 37mm, and the average self-transport speed is 0.9mm / s.

[0021] Example 2 - Single track The difference from Example 1 is that the substrate 1 is a Cu sheet, and the two rods 2 are Cu rods; the rest are the same as Example 1.

[0022] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 38.5 mm, and the average self-transport speed is 0.82 mm / s.

[0023] Example 3 - Single Track The difference from Example 1 is that the two rods 2 are ABS semi-cylinders, and the diameter of the bottom semicircle is 3 mm; the side where the plane of the ABS semi-cylinder is located is directly placed on the base 1; the rest is the same as Example 1.

[0024] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 32 mm, and the average self-transport speed is 0.41 mm / s.

[0025] Example 4 - Single Track The difference from Example 1 is that the two rods 2 are PMMA isosceles right triangular prisms, and the right angle side of the isosceles right triangle at the bottom is 1 mm; the side where the hypotenuse of the PMMA isosceles right triangular prism is located is directly placed on the base 1; the rest is the same as Example 1.

[0026] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 30 mm, and the average self-transport speed is 0.56 mm / s.

[0027] Example 5 - Single Track The difference from Example 1 is that: the two rods 2 are ABS regular quadrangular prisms, and the side length of the bottom regular quadrilateral is 3 mm; any side surface of the ABS regular quadrangular prism is directly placed on the base 1; the rest is the same as Example 1.

[0028] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 42 mm, and the average self-transport speed is 0.57 mm / s.

[0029] Example 6 - Single Track The difference from Example 1 is that the diameter of the two rods 2 is 2 mm; the rest is the same as Example 1.

[0030] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 36 mm, and the average self-transport speed is 0.77 mm / s.

[0031] Example 7 - Single Track The difference from Example 1 is that the diameter of the two rods 2 is 1 mm; the rest is the same as Example 1.

[0032] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 26 mm, and the average self-transport speed is 0.63 mm / s.

[0033] Example 8 - Single Track The difference from Example 1 is that in step S4, the viscosity of the dimethyl silicone oil is 10 cst; the rest is the same as Example 1.

[0034] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 41mm, and the average self-transport speed is 0.33mm / s.

[0035] Example 9 - Single Track The difference from Example 1 is that in step S4, the viscosity of the dimethyl silicone oil is 20 cst; the rest is the same as Example 1.

[0036] The application of the above-mentioned asymmetric smooth track: 20 microliters of water are dripped on the wide end of the "small V-shape", and the maximum self-transport displacement is 42 mm, and the average self-transport speed is 0.16 mm / s.

[0037] It can be seen from the results of Examples 1 to 5 that the present invention can be equipped with an asymmetric smooth track that is highly tolerant of the material and shape of the rod 2 and the base 1; and it can be seen from the results of Examples 1 and 6 to 9 that the speed and displacement of self-transport can be regulated by changing the diameter of the rod 2 or the viscosity of the dimethyl silicone oil.

[0038] Example 10 - Dual Tracks like Figure 4 As shown, an asymmetric smooth track that can be assembled is in the form of a double track, including a substrate 1 and four rods 2 located thereon, wherein two rods 2 form a group and one end of the two rods 2 is in a "large V shape" and is fixed together by 502 glue, and there are two groups of "large V shapes" in total; the narrow ends of the two groups of "large V shapes" are fixed to the substrate 1 by 502 glue in a manner of being spaced and facing each other; the angle of the "large V shape" is 177°; the surfaces of the rods 2 and the substrate 1 are both provided with a silicon dioxide super-hydrophobic coating, and the surface of the silicon dioxide super-hydrophobic coating is provided with a dimethyl silicone oil layer; the substrate 1 is a rectangular ABS sheet with a length of 200 mm, a width of 25 mm, and a thickness of 0.5 mm; the rod 2 is an ABS cylinder with a length of 100 mm and a diameter of 3 mm.

[0039] The preparation method of the above-mentioned asymmetric smooth track is as follows: S1, pretreatment 1: two rods 2 are grouped together and one end of the two rods 2 is in a "large V shape" (the angle is 177°) and fixed together by 502 glue, and there are two groups of "large V shapes" in total; S2, pretreatment 2: polish the entire outer surface of the two groups of "large V-shaped" rods and the substrate 1 with 2000 grit sandpaper, and rinse them with deionized water; S3, super-hydrophobic modification: immerse the two groups of "large V-shaped" rods and substrate 1 obtained in step S2 in a super-hydrophobic silica solution for 1 second, take them out, and wait for the solvent to evaporate completely; in terms of mass ratio, the super-hydrophobic silica solution is composed of dimethyl silicone oil: curing agent: n-hexane: super-hydrophobic silica nanoparticles (surface water droplet contact angle greater than 150°) = 10:1:21:8; S4, curing: the two groups of "large V-shaped" rods and the substrate 1 obtained in step S3 are placed in an oven at 80° C. and cured for 2 h; S5, oil layer injection: The two groups of "large V-shaped" rods obtained in step S4 and the substrate 1 are immersed in dimethyl silicone oil with a viscosity of 2 cst respectively, taken out after wetting, and placed vertically for 10 seconds to remove excess dimethyl silicone oil; S6, assembly: The narrow ends of the two groups of "large V-shaped" obtained in step S5 are fixed on the base 1 by means of 502 adhesive in a manner that they are spaced apart and face each other, thereby obtaining the corresponding asymmetric super-smooth track.

[0040] Example 11 - Three tracks like Figure 5 As shown, an asymmetric smooth track that can be assembled is in the form of three tracks, including a substrate 1 and six rods 2 located thereon, wherein two rods 2 form a group and one end of the two rods 2 is in a "large V' shape" and is fixed together by 502 glue, and there are a total of three groups of "large V' shapes"; the narrow ends of the three groups of "large V' shapes" are fixed to the substrate 1 by 502 glue at the three vertex positions of an equilateral triangle; the angle of the "large V' shape" is 117°; the surfaces of the rods 2 and the substrate 1 are both provided with a silicon dioxide super-hydrophobic coating, and the surface of the silicon dioxide super-hydrophobic coating is provided with a dimethyl silicone oil layer; the substrate 1 is an ABS disc with a radius of 100 mm and a thickness of 0.5 mm; the rod 2 is an ABS cylinder with a length of 100 mm and a diameter of 3 mm.

[0041] The preparation method of the above-mentioned asymmetric smooth track is as follows: S1, pretreatment 1: two rods 2 are grouped together and one end of the two rods 2 is in a "large V' shape" (the angle is 117°) and fixed together by 502 glue, with a total of three groups of "large V' shapes"; S2, pretreatment 2: polish the entire outer surface of the three groups of "large V-shaped" rods and the substrate 1 with 2000 grit sandpaper, and rinse them with deionized water; S3, super-hydrophobic modification: immerse the three groups of "large V'-shaped" rods and substrate 1 obtained in step S2 in a super-hydrophobic silica solution for 1 second, take them out, and wait for the solvent to evaporate completely; in terms of mass ratio, the super-hydrophobic silica solution is composed of dimethyl silicone oil: curing agent: n-hexane: super-hydrophobic silica nanoparticles (surface water droplet contact angle greater than 150°) = 10:1:21:8; S4, curing: the three groups of "large V'-shaped" rods and the substrate 1 obtained in step S3 are placed in an oven at 80°C for curing for 2 hours; S5, oil layer injection: the three groups of "large V'-shaped" rods obtained in step S4 and the substrate 1 are immersed in dimethyl silicone oil with a viscosity of 2 cst respectively, taken out after wetting, and placed vertically for 10 seconds to remove excess dimethyl silicone oil; S6. Assembly: The narrow ends of the three groups of "large V' shapes" obtained in step S5 are fixed on the base 1 at the three vertex positions of an equilateral triangle by means of 502 glue, so as to obtain the corresponding asymmetric super-smooth track.

[0042] Example 12 - Modular Track I like Figure 6 As shown in the left figure, an asymmetric smooth track that can be assembled is in the form of a modular track I, including module one, module two and module three. The structures of module one and module three are the same. Module one and module two are cut vertically downward from the same single track in Example 1, and module one is where the narrow end of the single track is located, and module two is where the wide end of the single track is located; module one and module two are placed together and the wide end of module one is connected to the narrow end of module two, and module three is placed independently of module one and module two.

[0043] The preparation method of the above-mentioned asymmetric smooth track is as follows: S1. According to the preparation method of Example 1, two single rails are prepared, one of which is cut vertically downward from the narrow end with a length of 15 mm, and the part where the narrow end of the single rail is located is marked as module one, and the part where the wide end of the single rail is located is marked as module two; the same operation is performed to cut another single rail, and the part where the narrow end of the single rail is located is marked as module three; S2, module one and module two are placed together and the wide end of module one is connected to the narrow end of module two, and module three is placed directly below module one independently of module one and module two, thus obtaining the corresponding asymmetric super-smooth track.

[0044] Example 13 - Modular Track II like Figure 7As shown in the left figure, an asymmetric smooth track that can be assembled is in the form of a modular track II, including module 1', module 2' and module 3'. Module 1' and module 3' are symmetrical structures with respect to the vertical plane. Module 2' and module 3' are cut vertically downward from the same single track in (1) and module 3' is where the narrow end of the single track is located, and module 2' is where the wide end of the single track is located; module 1' and module 2' are placed together and the narrow end of module 2' is connected to the narrow end of module 2', and module 3' is placed independently of module 1' and module 2'.

[0045] The preparation method of the above-mentioned asymmetric smooth track is as follows: S1. According to the preparation method of Example 1, two single rails are prepared, one of which is cut vertically downward from the narrow end with a length of 15 mm, and the part where the narrow end of the single rail is located is marked as module three', and the part where the wide end of the single rail is located is marked as module two'; the same operation is performed to cut another single rail, and the part where the narrow end of the single rail is located is horizontally reversed 180° and marked as module one'; S2, module one' and module two' are placed together and the narrow end of module one' is connected to the narrow end of module two', and module three' is placed directly above module one' independently of module one' and module two', thus obtaining the corresponding asymmetric super-smooth track.

[0046] Application Example 1 This application example uses the asymmetric smooth track with double tracks prepared in Example 10 for the reaction between micro-droplets. The specific operation steps are as follows: S1. Solution preparation: prepare 0.5 mol / L ferrous sulfate solution and 0.1 mol / L potassium permanganate solution respectively; S2, micro-droplet reaction: 20 μl of ferrous sulfate solution is dripped at the wide end of one track, and 20 μl of potassium permanganate solution is dripped at the wide end of the other track. The micro-droplets in the two tracks are simultaneously transported to the middle area of ​​the track until they merge in the middle of the track and start the reaction; S3, the color of the merged microdroplets gradually changed from purple to orange, proving the occurrence of the reaction; The above-mentioned double track can be equipped with an asymmetric smooth track to realize application in the field of micro-droplet reaction.

[0047] Application Example 2 This application example uses the asymmetric smooth track with three tracks prepared in Example 11 for the reaction and detection between micro-droplets. The specific operation steps are as follows: S1, solution preparation: prepare 0.5 mol / L potassium ferrocyanide solution, 0.5 mol / L sodium hydroxide solution and 0.1 mol / L ferrous sulfate solution respectively; S2, micro-droplet reaction: 20 μl of ferrous sulfate solution was added to the wide end of one track, and 20 μl of sodium hydroxide solution was added to the wide end of the other track. The micro-droplets in the two tracks were simultaneously transported to the middle area of ​​the track until they merged in the middle of the track and started to react. The solution changed from cyan to gray-green. S3. Potassium ferrocyanide solution is added dropwise to the wide end of the remaining track. After the solution is merged with the merged micro-droplets, the color of the micro-droplets changes from gray-green to blue, indicating the occurrence of the reaction.

[0048] The above three tracks can be assembled into an asymmetric smooth track to achieve application in the field of micro-droplet reaction and detection.

[0049] Application Example 3 This application example uses the asymmetric smooth track with three tracks prepared in Example 11 for micro-droplet pH detection. The specific operation steps are as follows: S1. Solution preparation: prepare 0.5 mol / L hydrochloric acid, 0.5 mol / L sodium hydroxide solution and 0.1 mol / L methyl orange solution respectively; S2, micro-droplet reaction: 20 μl of hydrochloric acid is added to the wide end of one track, and 20 μl of methyl orange solution is added to the wide end of the other track. The micro-droplets in the two tracks are simultaneously transported to the middle area of ​​the track until they merge in the middle of the track, and the reaction begins. The solution changes from orange to dark red; S3. Add sodium hydroxide solution at the wide end of the remaining track. After merging with the merged micro-droplets again, the color of the micro-droplets changes from dark red back to orange, thereby realizing the detection of the acidity and alkalinity of the micro-droplets.

[0050] The above three tracks can be assembled into an asymmetric smooth track to achieve application in the field of micro-droplet pH detection.

[0051] Application Example 4 This application example uses the asymmetric smooth track with modular track I prepared in Example 12 for the splitting and transfer of microdroplets. The specific operation steps are as follows: S1. Solution preparation: prepare a dye droplet with a blue water-soluble pigment dye (purchased from Guangzhou Kelaiya Chemical Co., Ltd.) at a mass ratio of dye: water = 1:10000; S2, micro-droplet reaction: 40 μl of micro-droplets are dripped into the track of module one from the narrow end of module one, and the micro-droplets begin to move into the track of module two; S3, wait until the micro droplets are transported to the middle area (equilibrium position) between module 1 and module 2 and stop moving, then transfer module 2 until it is connected to module 3 (such as Figure 6As shown in the right figure), the microdroplets realize self-transportation from module 2 to module 3 (in the process of moving module 2 to module 3, the droplet is split from the middle, and a part is retained on module 1 and module 2. Therefore, when it contacts module 3, the volume of the droplet has actually been reduced by half, causing the equilibrium position to shift to the left, so it will move to module 3); S4. Transfer module 2 again until it is connected to module 1, and repeat steps S2 and S3 to prove the stability of modular track I.

[0052] The above modular asymmetric smooth track is applied in micro-droplet splitting-transfer.

[0053] Application Example 5 This application example uses the asymmetric super-smooth track with modular track II prepared in Example 13 for merging and transferring between micro-droplets. The specific operation steps are as follows: S1. Solution preparation: prepare 0.5 mol / L potassium permanganate solution and 0.1 mol / L ferrous sulfate solution respectively; S2, micro-droplet reaction: add 20 microliters of ferrous sulfate micro-droplets into the track at the wide end of module 1', and add 20 microliters of potassium permanganate solution micro-droplets into the wide end of module 2'. The micro-droplets in the two tracks are simultaneously transported to the middle area of ​​the track until they merge in the middle of the track and are transferred to the narrow end of the track of module 2'. S3, transfer module 2' until it is connected to module 3' (such as Figure 7 As shown in the right figure), the microdroplets realize self-transportation from module 2' to module 3'; S4. Transfer module 2' again until it is connected to module 1', and repeat steps S2 and S3 to prove the stability of modular track II.

[0054] The modular asymmetric smooth track is applied in micro-droplet merging and transfer.

[0055] Bubble Example Example 14 - Single Track like Figure 1 and 8As shown, an asymmetric smooth track that can be assembled is in the form of a single track, including a substrate 1 and two rods 2 located thereon, the two rods 2 are in a "small V shape" and are bonded to the substrate 1 by 502 glue, and the two rods 2 intersect at the narrow end of the "small V shape"; the angle of the "small V shape" is 3°; the surfaces of the rods 2 and the substrate 1 are both provided with a silicon dioxide super-hydrophobic coating, and the surface of the silicon dioxide super-hydrophobic coating is provided with a dimethyl silicone oil layer; the substrate 1 is a rectangular ABS sheet with a length of 100 mm, a width of 25 mm, and a thickness of 0.5 mm; the two rods 2 are ABS right quadrangular prisms, one of the two adjacent sides of the bottom rectangle is 1.5 mm long, and the other side is 3 mm long, and the side of the ABS right quadrangular prism where the side length of 1.5 mm is located is bonded to the substrate 1 by 502 glue.

[0056] The preparation method of the above-mentioned asymmetric smooth track is as follows: S1, pretreatment: polish the entire outer surface of the two rods 2 and the substrate 1 with 2000 grit sandpaper, and rinse with deionized water; S2, super-hydrophobic modification: immerse the two rods 2 and the substrate 1 obtained in step S1 in a super-hydrophobic silica solution for 1 second, take them out, and wait for the solvent to evaporate completely; in terms of mass ratio, the super-hydrophobic silica solution is composed of PDMS: curing agent: n-hexane: super-hydrophobic silica nanoparticles (surface water droplet contact angle greater than 150°) = 10:1:21:8; S3, curing: the two rods 2 and the substrate 1 obtained in step S2 are placed in an oven at 80° C. and cured for 2 h; S4, oil layer injection: The two rods 2 and the substrate 1 obtained in step S3 are immersed in dimethyl silicone oil with a viscosity of 2 cst respectively, taken out after wetting, and placed vertically for 10 seconds to remove excess dimethyl silicone oil; S5, assembly: The two rods 2 obtained in step S4 are bonded to the substrate 1 at an angle of 3° using 502 glue to obtain the corresponding asymmetric super-smooth track.

[0057] Application of the above-mentioned asymmetric smooth track: Place the above-mentioned asymmetric smooth track in water, and then introduce 20 microliters of air bubbles into the wide end of the "small V-shape" through a pipette, the maximum self-transport displacement is 47 mm, and the average self-transport speed is 2.07 mm / s.

[0058] Example 15 - Single Track The difference from Example 14 is that in step S4, the viscosity of the dimethyl silicone oil is 10 cst; the rest is the same as Example 14.

[0059] Application of the above-mentioned asymmetric smooth track: Place the above-mentioned asymmetric smooth track in water, and then introduce 20 microliters of air bubbles into the wide end of the "small V-shape" through a pipette, the maximum self-transport displacement is 52 mm, and the average self-transport speed is 0.86 mm / s.

[0060] Example 16 - Single Track The difference from Example 14 is that in step S4, the viscosity of the dimethyl silicone oil is 20 cst; the rest is the same as Example 14.

[0061] Application of the above-mentioned asymmetric smooth track: The above-mentioned asymmetric smooth track is placed in water, and then 20 microliters of air bubbles are introduced into the wide end of the "small V-shape" through a pipette, and its maximum self-transport displacement is 51 mm, and the average self-transport speed is 0.42 mm / s.

[0062] Example 17 - Single Track like Fig. 9 As shown, the difference from Example 14 is that the two rods 2 do not intersect at the narrow end of the "small V-shape" and maintain a spacing of W=1mm; the rest is the same as Example 14.

[0063] Application of the above-mentioned assembleable asymmetric smooth track: place the above-mentioned assembleable asymmetric smooth track in water, and then continuously introduce 40 microliters of air bubbles at the wide end of the "small V-shape" through a pipette (that is, 40 microliters of air bubbles are introduced at the wide end of the "small V-shape" for the first time, and the introduced bubbles are spontaneously transported to the narrow end of the track. When they move to the narrow end of the "small V-shape", 40 microliters of air bubbles are introduced at the same position of the wide end for the second time. When they move to the narrow end and merge with the previous bubbles, 40 microliters of air bubbles are introduced at the same position of the wide end for the third time, and so on and so forth). When the volume of the bubbles in the track exceeds a certain range, the bubbles are released from the track. It is recorded that the position where the bubbles are released from the track into the environment is 28 mm (this position is measured from the position where the air bubbles are introduced at the wide end of the "small V-shape").

[0064] Example 18 - Single Track like Fig. 9 As shown, the difference from Example 14 is that the two rods 2 do not intersect at the narrow end of the "small V-shape" and maintain a spacing of W=2mm; the rest is the same as Example 14.

[0065] Application of the above-mentioned assembleable asymmetric smooth track: Place the above-mentioned assembleable asymmetric smooth track in water, and then use the same method as Example 17 to continuously introduce 40 microliters of air bubbles at the wide end of the "small V-shape" through a pipette, and the position where the bubbles are released from the track into the environment is 14 mm.

[0066] Example 19 - Single Track like Fig. 9 As shown, the difference from Example 14 is that the two rods 2 do not intersect at the narrow end of the "small V-shape" and maintain a spacing of W=3mm; the rest is the same as Example 14.

[0067] Application of the above-mentioned assembleable asymmetric smooth track: Place the above-mentioned assembleable asymmetric smooth track in water, and then use the same method as Example 17 to continuously introduce 40 microliters of air bubbles at the wide end of the "small V-shape" through a pipette, and the position where the bubbles leave the track and are released into the environment is 8 mm.

[0068] Example 20 - Dual Tracks like Figure 4 As shown, an asymmetric smooth track that can be assembled is in the form of a double track, including a substrate 1 and four rods 2 located thereon, wherein two rods 2 form a group and one end of the two rods 2 is in a "large V shape" and is fixed together by 502 glue, and there are two groups of "large V shapes" in total; the narrow ends of the two groups of "large V shapes" are fixed to the substrate 1 by 502 glue in a manner of being spaced and facing each other; the angle of the "large V shape" is 177°; the surfaces of the rods 2 and the substrate 1 are both provided with a silicon dioxide super-hydrophobic coating, and the surface of the silicon dioxide super-hydrophobic coating is provided with a dimethyl silicone oil layer; the substrate 1 is a rectangular ABS sheet with a length of 200 mm, a width of 25 mm, and a thickness of 0.5 mm; the two rods 2 are ABS right quadrangular prisms, one of the two adjacent sides of the bottom rectangle is 1.5 mm long, and the other side is 3 mm long, and the side of the ABS right quadrangular prism where the side length of 1.5 mm is located is bonded to the substrate 1 by 502 glue.

[0069] The preparation method of the above-mentioned asymmetric smooth track is as follows: S1, pretreatment 1: two rods 2 are grouped together and one end of the two rods 2 is in a "large V shape" (the angle is 177°) and fixed together by 502 glue, and there are two groups of "large V shapes" in total; S2, pretreatment 2: polish the entire outer surface of the two groups of "large V-shaped" rods and the substrate 1 with 2000 grit sandpaper, and rinse them with deionized water; S3, super-hydrophobic modification: immerse the two groups of "large V-shaped" rods and substrate 1 obtained in step S2 in a super-hydrophobic silica solution for 1 second, take them out, and wait for the solvent to evaporate completely; in terms of mass ratio, the super-hydrophobic silica solution is composed of dimethyl silicone oil: curing agent: n-hexane: super-hydrophobic silica nanoparticles (surface water droplet contact angle greater than 150°) = 10:1:21:8; S4, curing: the two groups of "large V-shaped" rods and the substrate 1 obtained in step S3 are placed in an oven at 80° C. and cured for 2 h; S5, oil layer injection: The two groups of "large V-shaped" rods obtained in step S4 and the substrate 1 are immersed in dimethyl silicone oil with a viscosity of 2 cst respectively, taken out after wetting, and placed vertically for 10 seconds to remove excess dimethyl silicone oil; S6, assembly: The narrow ends of the two groups of "large V-shaped" obtained in step S5 are fixed on the base 1 by means of 502 adhesive in a manner that they are spaced apart and face each other, thereby obtaining the corresponding asymmetric super-smooth track.

[0070] Application Example 6 This application example uses the asymmetric smooth track with double tracks prepared in Example 20 for mixing reaction between gases. The specific operation steps are as follows: S1. Material preparation: prepare the hydrogen and oxygen required for the experiment; S2, micro-droplet reaction: the above-mentioned asymmetric smooth track is placed in water, 40 microliters of hydrogen bubbles are introduced into the wide end of one track, and 40 microliters of oxygen bubbles are introduced into the wide end of the other track, and the bubbles in the two tracks are simultaneously transported to the middle area of ​​the track until they merge in the middle of the track and begin to mix; S3. Use an electronic igniter to ignite the mixed gas to prove that mixing of the two gases occurs; The above-mentioned double track can be equipped with an asymmetric smooth track to realize application in the field of gas mixing reaction.

[0071] Application Example 7 This application example uses the asymmetric super-smooth track with a narrow end spacing of 1 mm and a single track prepared in Example 17 for gas collection. The specific operation steps are as follows: S1. Instrument preparation: pipette; S2. Air bubbles are introduced quantitatively and continuously at the wide end of the track. The introduced air bubbles are spontaneously transported to the narrow end of the track and gathered at the narrow end. S3. When the volume of the bubbles in the track exceeds a certain range, the gas is released from the track in the form of bubbles, and the released bubbles are collected by a funnel-shaped collecting device.

[0072] The above-mentioned single track can be equipped with an asymmetric smooth track to realize application in the field of gas collection.

Claims

1. A kind of asymmetric smooth track, characterized in that: The assembly form of the asymmetric smooth track is one of the following: single track, double track, triple track, modular track I, modular track II: (1) Single track: It includes a base and two rods located thereon. The two rods are directly placed or fixed on the base in a "small V shape". The two rods intersect or do not intersect at the narrow end of the "small V shape". The angle of the "small V shape" is α; (2) Double track: It includes a base and four rods located thereon, wherein two rods form a group and one end of the two rods are intersected and fixed together in a "large V shape", with a total of two groups of "large V shapes"; the narrow ends of the two groups of "large V shapes" are directly placed or fixed on the base in a manner of being spaced and facing each other; the angle of the "large V shape" is 180°-α; (3) Three tracks: including a base and six rods located thereon, wherein two rods form a group and one end of the two rods intersect and are fixed together in a "large V' shape", with a total of three groups of "large V' shapes"; the narrow ends of the three groups of "large V' shapes" are directly placed or fixed on the base in the form of three vertex positions of an equilateral triangle; the angle of the "large V' shape" is 120°-α; (4) Modular track I: including module 1, module 2 and module 3. Module 1 and module 3 have the same structure. Module 1 and module 2 are cut vertically downward from the same single track in (1). Module 1 is the narrow end of the single track, and module 2 is the wide end of the single track. Module 1 and module 2 are placed together and the wide end of module 1 is connected to the narrow end of module 2. Module 3 is placed independently of module 1 and module 2. (5) Modular track II: including module 1', module 2' and module 3'. Module 1' and module 3' are symmetrical structures with respect to the vertical plane. Module 2' and module 3' are cut vertically downward from the same single track in (1). Module 3' is the narrow end of the single track, and module 2' is the wide end of the single track. Module 1' and module 2' are placed together and the narrow end of module 1' is connected to the narrow end of module 2'. Module 3' is placed independently of module 1' and module 2'. The degree of α is 3-9°; the surfaces of the rod and the substrate are both provided with a silicon dioxide super-hydrophobic coating, and the surface of the silicon dioxide super-hydrophobic coating is provided with a dimethyl silicone oil layer.

2. The asymmetric smooth track as claimed in claim 1, characterized in that: The shape of the base is rectangular or circular; the shape of the rod is a cylinder, a semi-cylinder, an isosceles right triangular prism or a straight quadrangular prism; when the rod is a semi-cylinder, the side where the plane of the semi-cylinder is located is directly placed or fixed on the base; when the rod is an isosceles right triangular prism, the side where the hypotenuse of the isosceles right triangular prism is located is directly placed or fixed on the base; when the rod is a straight quadrangular prism, any side of the straight quadrangular prism is directly placed or fixed on the base.

3. The asymmetric smooth track as claimed in claim 1, characterized in that: The material of the substrate is ABS or Cu; the material of the rod is ABS, Cu or PMMA.

4. The asymmetric smooth track as claimed in claim 1, characterized in that: All the fixing methods involved are adhesive fixing.

5. A method for preparing an asymmetric smooth rail according to any one of claims 1 to 4, characterized in that: Here are the steps: S1. Use sandpaper to polish the entire outer surface of the rod and the base, and rinse them with water; S2, immersing the rod and substrate obtained in step S1 in a silicon dioxide super-phobic solution, taking them out after wetting, and waiting for the solvent to evaporate completely; S3, curing the rod and the substrate obtained in step S2 at 60-80° C. for 1-3 hours respectively; S4, immersing the rod and the substrate obtained in step S3 in dimethyl silicone oil with a viscosity of 2-20 cst respectively, taking them out after wetting, and placing them vertically to remove excess dimethyl silicone oil; S5. Assemble the rod obtained in step S4 and the base according to one of the assembly forms (1) to (5) to obtain the corresponding asymmetric super-smooth track.

6. The method for preparing an asymmetric smooth rail as claimed in claim 5, characterized in that: In terms of mass ratio, the silica super-hydrophobic aqueous solution is composed of PDMS: curing agent: n-hexane: super-hydrophobic silica nanoparticles = (9-11): (0.9-1.1): (17-28): (6-10), and the curing agent is a curing agent used in conjunction with PDMS.

7. The method for preparing an asymmetric smooth rail as claimed in claim 6, characterized in that: The contact angle of water droplets on the surface of superhydrophobic silica nanoparticles is greater than 150°.

8. The method for preparing an asymmetric smooth rail as claimed in claim 5, characterized in that: The sandpaper is 400-2000 grit sandpaper.

9. Use of the assembleable asymmetric smooth track as claimed in any one of claims 1 to 4 in self-transportation of micro-droplets.

10. Use of the assembleable asymmetric smooth track as claimed in any one of claims 1 to 4 in self-transportation of bubbles in water.

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