Liquid-like surface large particle multi-type solid-liquid control method based on pyroelectric effect

Abstract

The invention discloses a liquid-like surface large particle multi-type solid-liquid control method based on a pyroelectric effect. The method comprises the following steps: step 1, pretreating a pyroelectric wafer material; step 2, performing liquid phase modification on the pyroelectric wafer; step 3, preparing a photo-thermal response material; step 4, operating platform combination; step 5, directional control of liquid drops; and step 6, performing directional control on the solid particles. The control platform designed by the invention is formed by combining three layers of materials in a blocking manner, the preparation process is simple, the solid-liquid control operation method is simple and convenient, and the production cost is relatively low. According to the control platform, a liquid-like surface and a pyroelectric material are combined, on the basis that the friction force between a solid and the surface of the platform is greatly reduced on the liquid-like surface, local charge gradient is generated on the surface by means of the response mechanism of the pyroelectric material, and direct control over the solid material is achieved under the action of dielectrophoretic force; the innovative microfluidic platform and solid control mode greatly widen the practical application of the technical field of microfluidic.

Description

Technical Field

[0001] This invention belongs to the field of non-contact solid-liquid manipulation technology of super-slippery surfaces, and relates to the design of a large-particle multi-type solid manipulation platform based on pyroelectric effect and a solid particle manipulation method. Background Technology

[0002] Droplet manipulation plays a crucial role in basic research and practical applications, especially when combined with smart materials and external fields to achieve multifunctional droplet manipulation. Microfluidic platforms can achieve non-contact directional transport of droplets. However, in order to better adapt to practical applications in biomedicine, chemistry and other fields, microfluidic platforms with faster transport speeds, longer movement distances, more flexible droplet manipulation and the ability to manipulate diverse substances are receiving increasing attention.

[0003] Currently, microfluidic technology focuses solely on the manipulation of droplets. While non-contact, flexible manipulation of droplets has been achieved through external stimuli such as light, electricity, and magnetism, a direct, non-contact manipulation platform for millimeter-scale solid particles on surfaces has yet to emerge. Although some microfluidic platforms achieve indirect transport of solid materials through droplet transport, this method firstly causes some contamination of the solid material, affecting its subsequent use; secondly, the type of solid material that can be transported is limited, only transporting inert, low-density solids that do not react with droplets, and the shape and size of the transported material are also restricted. Therefore, developing a direct, non-contact solid transport platform is of great significance for the further application of microfluidic technology in fields such as medicine, chemistry, and new energy. Summary of the Invention

[0004] To address the limitation of current microfluidic platforms in directly manipulating solid particles, this invention provides a method for manipulating large particles on liquid-like surfaces using pyroelectric effects. The solid-liquid manipulation platform designed using this method can not only manipulate droplets but also directly manipulate almost all organic, inorganic, and metallic solid particles. The shape of the manipulated solid is not limited; it can manipulate cylindrical, irregularly shaped, hemispherical, and annular particles, and can achieve directional manipulation and fusion reactions between solids and liquids in a non-contact state.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for manipulating large particles on liquid-like surfaces and various solid-liquid hybrids based on pyroelectric effects includes the following steps:

[0007] Step 1: Pretreatment of pyroelectric wafer material: The pyroelectric wafer is rinsed sequentially with acetone, ultrapure water, and isopropanol to thoroughly remove surface stains and ensure surface cleanliness. Then, it is taken out and dried with nitrogen gas. The relatively clean side is placed in a plasma cleaner for oxygen plasma treatment of the wafer surface. The pyroelectric wafer is one of lithium niobate (LiNbO3) or lithium tantalate (LiTaO3), with a size of 10~100mm×10~100mm×0.5~2mm.

[0008] Step 2: Liquid-phase modification of pyroelectric wafers: Take 50-1500 μL of silane molecules, dissolve them in 5-20g of solvent, stir evenly, then add 0.5-5μL of ultrapure water and stir thoroughly for 1-3 min. Let stand at room temperature for 2-15 min, then immerse the treated pyroelectric wafers in the prepared silane molecule solution for 15-100 min. After immersion, ultrasonically clean them in a solvent for 3-15 min. The monomolecular silane is one of methyldichlorosilane, dimethyldichlorosilane, 1,2-dichlorotetramethyldisilane, trichlorosilane, methyltrichlorosilane, or (chloromethyl)dimethylchlorosilane. The solvent is toluene or isopropanol.

[0009] Step 3: Preparation of photothermal responsive material: Take 10-100 g of polydimethylsiloxane resin and add 1-20 g of curing agent, stir magnetically for 3-20 min, then add 0.1-10 g of photothermal responsive particles to the resin mixture, sonicate for 5-15 min, and continue stirring for 3-15 min. Pour the uniformly stirred composite resin into a mold, remove air bubbles in a vacuum chamber, place a portion at room temperature for 0.5-3 hours to semi-cur it, and place the other portion in an oven at 60-100 ℃ for 1-2 hours to obtain the photothermal responsive material; the photothermal responsive particles are one of carbon black, iron oxide nanoparticles, carbon nanotubes, graphene, and MXene.

[0010] Step 4: Assembly of the control platform: Take 2-10 g of semi-cured resin from Step 3 and drop it onto the lower surface of the pyroelectric chip modified in Step 2. Then, turn on the spin coater to evenly spin coat the semi-cured resin onto the lower surface of the pyroelectric chip. After that, attach it to the cured photothermal response material and place it in an oven at 60-100 ℃ for 1-2 hours to obtain the control platform. Then, fix a 300-1500 mW near-infrared light source (808 nm) on the XY dual-axis screw propeller at a position 5-20 cm above the platform. The control platform assembly is now complete.

[0011] Step 5: Droplet Orientation Manipulation: Use a pipette to place a 1-50 μL droplet onto the surface of the solid-liquid manipulation platform. Turn on the near-infrared light source and adjust the position of the light source using the XY dual-axis helical propeller to achieve directional driving of the droplet; the droplet is an electronic fluorinated liquid FC 72, electronic fluorinated liquid FC 770, electronic fluorinated liquid FC 40, electronic fluorinated liquid Novec 7500, electronic fluorinated liquid Novec 7000, or electronic fluorinated liquid FC. 70. Perfluoropolyether lubricant GPL101 contains one or more of the following solvents: n-hexane, n-heptane, n-nonane, cyclohexane, n-hexadecane, carbon tetrachloride, 1,4-dioxane, p-xylene, benzene, toluene, m-xylene, triethylamine, o-xylene, diethylamine, bromobenzene, diiodomethane, chlorobenzene, ethyl acetate, ethyl benzoate, acetic acid, methyl acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, tert-butanol, pyridine, isobutanol, 1-propanol, acetone, ethanol, hexamethylphosphoramide, N-methylpyrrolidone (NMP), methanol, nitrobenzene, ethylene glycol, acetonitrile, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), glycerol, dimethyl sulfoxide (DMSO), formic acid, water, and formamide.

[0012] Step Six: Oriented Manipulation of Solid Particles: Use tweezers to pick up an irregularly shaped solid material and place it on the surface of the solid-liquid manipulation platform. Turn on the near-infrared light source and adjust the position of the light source using the XY dual-axis screw propeller to achieve direct directional driving of the solid material. The irregular shape is one of the following: cube, cylinder, triangular prism, hemisphere, sphere, irregular prism, and hollow cylinder. The solid material is one or more of the following twenty solid materials: perfluoroethylene propylene copolymer (FEP), polytetrafluoroethylene, polyethylene, polypropylene, polystyrene (PS), Surlyn resin, polymethyl methacrylate (PMMA), polyacrylaldehyde, polylactic acid (PLA), epoxy resin (EP), nylon 66, potassium permanganate (KMnO4), sodium chloride (NaCl), soda-lime glass, silicon nitride, zirconium oxide ceramic, ferrous sulfate heptahydrate (FeSO4·7H2O), copper (Cu), aluminum, and stainless steel.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] (1) The control platform designed in this invention can not only control liquids, but also directly control large solid particles of various shapes at the millimeter level without contact, which greatly broadens the practical application of the microfluidics technology field.

[0015] (2) The surface of the control platform designed in this invention is a liquid-like surface, which not only achieves low viscosity of droplets but also greatly reduces the friction of solid substances on the surface, significantly increasing the types of solids and liquids that the platform can control, giving it great universality in material control.

[0016] (3) The control platform designed in this invention has excellent environmental stability. After being placed under natural conditions for 150 days, it still has excellent low viscosity for droplets and maintains excellent low frictional resistance for solid materials.

[0017] (4) The control platform designed in this invention has excellent anti-friction stability. After 100 times of contact and friction of solid materials, its performance of low viscosity of droplets and low frictional resistance of solid materials has hardly decreased.

[0018] (5) The control platform designed in this invention is composed of three layers of material in a modular combination. The preparation process is simple, the solid-liquid control operation method is convenient, and the production cost is low.

[0019] (6) The control platform designed in this invention combines a liquid-like surface and a pyroelectric material. Based on the liquid-like surface, the friction between the solid and the platform surface is greatly reduced. The pyroelectric material generates a local charge gradient on the surface by relying on the response mechanism. Under the action of dielectric force, the solid material can be directly controlled. This innovative microfluidic platform and solid control method greatly broadens the practical application of the microfluidic technology field. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the solid-liquid manipulation platform.

[0021] Figure 2 This is a schematic diagram of a solid-liquid manipulation platform for directional manipulation of solids.

[0022] Figure 3 A schematic diagram illustrating the solid manipulation process of a solid-liquid manipulation platform.

[0023] Figure 4 The graph shows the variation of the sliding angle of droplets with different surface tensions and volumes on the surface of the solid-liquid manipulation platform.

[0024] Figure 5 The sliding friction stress diagrams of the solid-liquid manipulation platform surface before and after modification with a 5N force on a liquid-like surface for ten solid substances.

[0025] Figure 6 The trends of surface sliding angle (SA) and contact angle hysteresis (CAH) of water (a) and hexadecane (b) after a long period of static storage on a solid-liquid manipulation platform are shown.

[0026] Figure 7The graph shows the changes in the sliding angle of the solid-liquid control platform to water and the sliding friction stress to epoxy after 100 cycles of friction with epoxy resin.

[0027] Figure 8 The curves show the light transmittance of pyroelectric crystal materials before and after surface modification with liquid;

[0028] Figure 9 The curve of surface temperature change of the solid-liquid manipulation platform over time under near-infrared light irradiation;

[0029] Figure 10 Photographs showing the movement of cylindrical epoxy resin, irregularly shaped ferrous sulfate heptahydrate, and hollow annular copper foil controlled by a solid-liquid control platform. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0031] Example 1:

[0032] Take one piece Lithium niobate (LiNbO3) wafers were immersed in acetone solution and sonicated for 5 min. After removal, they were placed in ultrapure water solution and sonicated for 5 min, then removed and placed in isopropanol solution for another 5 min of sonication. The surface was then removed with tweezers and dried with nitrogen. Next, the surface was subjected to oxygen plasma treatment (75 W, 3 min) in an oxygen plasma cleaner. Subsequently, 1000 μL of 1,2-dichlorotetramethyldisilane was dissolved in 15 g of toluene and stirred until homogeneous. Then, 4 μL of ultrapure water was added and stirred thoroughly for 2 min, followed by standing at room temperature for 10 min. The treated lithium niobate wafers were then immersed in a prepolymerized solution for 60 min, followed by sonication in isopropanol for 5 min, and finally dried with nitrogen. Take 100 g of polydimethylsiloxane resin and 10 g of commercial curing agent, stir magnetically for 10 min, then add 3 g of iron oxide nanoparticles, stir and sonicate for 10 min, then stir magnetically for 10 min. Pour the mixture into a mold and remove air bubbles in a vacuum chamber. Part of the mixture is left at room temperature for 2 hours to semi-cur, while the other part is placed in an oven at 80 ℃ for 2 hours to cure. Then, apply some semi-cured mixed resin to the lower surface of the treated lithium niobate wafer, attach it to the surface of the cured photothermal responsive material resin block, and place it in an oven at 80 ℃ for 1 hour to obtain a solid-liquid manipulation platform. Use a pipette to take 5 μL of water droplets, 5 μL of formamide droplets, 5 μL of n-hexadecane, and 5 μL of electronic fluorinated liquid FC 72 and place them on the surface of the manipulation platform. Turn on a 1000 mW near-infrared light source, and adjust the position of the light source using an XY dual-axis helical propeller to achieve directional driving of the four droplets. After removing the droplets with a pipette, use tweezers to place cylindrical epoxy resin, irregularly shaped ferrous sulfate heptahydrate, and hollow annular copper foil on the surface of the control platform. Turn on a 1000 mW near-infrared light source and adjust the position of the light source through an XY dual-axis screw propeller to achieve directional driving of the three solid substances.

[0033] The materials obtained in this embodiment were subjected to the following tests:

[0034] (1) such as Figure 4 As shown, all seven types of droplets with low to high surface tension exhibit low viscosity at very low sliding angles on the control surface, and the sliding angle decreases as the droplet volume increases.

[0035] (2) such as Figure 5 As shown, ten solid substances significantly reduced the sliding friction stress on the control platform surface of the modified liquid surface.

[0036] (3) such as Figure 6 As shown, high surface tension droplets, represented by water, and low surface tension droplets, represented by n-hexadecane, still maintain excellent low viscosity on the surface of the control platform after 150 days.

[0037] (4) such as Figure 8 As shown, the light transmittance of the pyroelectric material wafer did not decrease before and after the liquid-like surface treatment, and even increased slightly under some spectral irradiation, ensuring good light transmission.

[0038] (5) such as Figure 9 As shown, under near-infrared light irradiation with a power of 1000 mW, the surface temperature can be rapidly increased from 22 °C to 45 °C within 5 seconds, and then rapidly decreased after being turned off. This provides a good temperature gradient for the pyroelectric material, ensuring the formation of surface charge.

[0039] (6) For example Figure 10 As shown, three solids—cylindrical epoxy resin, irregularly shaped ferrous sulfate heptahydrate, and hollow annular copper foil—can be effectively driven on the surface of the control platform.

[0040] Example 2:

[0041] Take one piece Lithium tantalate (LiTaO3) wafers were immersed in acetone solution and sonicated for 5 min. After removal, they were placed in ultrapure water solution and sonicated for 5 min, then removed and placed in isopropanol solution for another 5 min of sonication. The surface was then removed with tweezers and dried with nitrogen. Next, the surface was treated with oxygen plasma (75 W, 3 min) in an oxygen plasma cleaner. Then, 500 μL of dimethyldichlorosilane was dissolved in 10 g of toluene and stirred until homogeneous. 2 μL of ultrapure water was added and stirred thoroughly for 1 min, then allowed to stand at room temperature for 5 min. The treated lithium tantalate wafers were immersed in a prepolymerized solution for 60 min, then sonicated in isopropanol for 5 min, and dried with nitrogen. 50 g of polydimethylsiloxane resin and 5 g of commercial curing agent were magnetically stirred for 10 min, then 0.5 g of carbon nanotubes were added. The mixture was stirred and sonicated for 15 min, then magnetically stirred for another 15 min. The mixture was then poured into a mold and vacuum-sealed to remove air bubbles. One portion was left at room temperature for 2 hours to semi-cure, while the other portion was cured in an oven at 80 °C for 2 hours. Next, a semi-cured mixed resin is applied to the lower surface of the treated lithium tantalate wafer, which is then bonded to the surface of the cured photothermal responsive material resin block. The substrate is then cured in an oven at 80 °C for 1 hour to obtain the solid-liquid manipulation platform. Using a pipette, 10 μL of water, 10 μL of glycerol, 10 μL of toluene, and 10 μL of acetonitrile are placed on the surface of the solid-liquid manipulation platform. An 800 mW near-infrared light source is turned on, and the position of the light source is adjusted using an XY dual-axis screw propeller to achieve directional actuation of the four types of droplets. After removing the droplets with a pipette, cylindrical polymethyl methacrylate, irregularly shaped sodium chloride, and hollow annular aluminum foil are placed on the surface of the manipulation platform using tweezers. An 800 mW near-infrared light source is turned on, and the position of the light source is adjusted using an XY dual-axis screw propeller to achieve directional actuation of the three solid substances in the same way.

[0042] The materials obtained in this embodiment were subjected to the following tests:

[0043] like Figure 7 As shown, after being rubbed with epoxy resin 100 times, the surface of the control platform still exhibits low viscosity to water and low frictional resistance to epoxy resin solid materials.

Claims

1. A method for manipulating large particles on liquid-like surfaces and various solid-liquid analogues based on pyroelectric effects, characterized in that... The method includes the following steps: Step 1: Pretreatment of pyroelectric wafer material: Rinse the surface of the pyroelectric wafer with acetone, ultrapure water and isopropanol in sequence to thoroughly remove surface stains and ensure surface cleanliness. Then take it out and blow dry the surface with nitrogen. Place the cleaned side in a plasma cleaner to perform oxygen plasma treatment on the wafer surface. Step 2, Liquid phase modification of pyroelectric wafers: Take 50~1500 μL of silane molecules, dissolve them in 5~20g of solvent and stir evenly. Then add 0.5~5μL of ultrapure water and stir thoroughly for 1~3 min. Let it stand at room temperature for 2~15 min. Then place the treated pyroelectric wafers in the prepared silane molecule solution and soak for 15~100 min. After soaking, place them in the solvent and ultrasonically clean for 3~15 min. Step 3: Preparation of photothermal responsive material: Take 10-100 g of polydimethylsilicone resin and add 1-20 g of curing agent, stir with a magnetic stirrer for 3-20 min, then take 0.1-10 g of photothermal responsive particles and add them to the resin mixture, sonicate for 5-15 min and continue stirring for 3-15 min, pour the uniformly stirred composite resin into a mold, remove air bubbles in a vacuum chamber, place a portion at room temperature for 0.5-3 hours to semi-cur it, and place the other portion in an oven at 60-100 ℃ for 1-2 hours to obtain the photothermal responsive material; Step 4: Control Platform Assembly: Take 2-10 g of semi-cured resin from Step 3 and drop it onto the lower surface of the pyroelectric chip modified in Step 2. Then, turn on the spin coater to evenly spin coat the semi-cured resin onto the lower surface of the pyroelectric chip. After that, attach it to the cured photothermal response material and place it in an oven at 60-100 ℃ for 1-2 hours to obtain the control platform. Then, fix the near-infrared light source on the XY dual-axis screw propeller at a position 5-20 cm above the platform. The control platform assembly is now complete. Step 5, Droplet Orientation Manipulation: Use a pipette to take 1~50 μL of droplet and place it on the surface of the solid-liquid manipulation platform. Turn on the near-infrared light source and adjust the position of the light source through the XY dual-axis screw propeller to achieve directional driving of the droplet. Step 6: Oriented manipulation of solid particles: Use tweezers to pick up an irregularly shaped solid material and place it on the surface of the solid-liquid manipulation platform. Turn on the near-infrared light source and adjust the position of the light source through the XY dual-axis screw propeller to achieve direct directional driving of the solid material.

2. The method for manipulating large particles on liquid-like surfaces and various solid-liquid analogues based on pyroelectric effects according to claim 1, characterized in that... In step one, the pyroelectric crystal is either lithium niobate or lithium tantalate, and its size is 10~100mm×10~100mm×0.5~2mm.

3. The method for manipulating large particles on liquid-like surfaces and various solid-liquid hybrids based on pyroelectric effects according to claim 1, characterized in that... In step two, the monomolecular silane is one of methyldichlorosilane, dimethyldichlorosilane, 1,2-dichlorotetramethyldisilane, trichlorosilane, methyltrichlorosilane, or (chloromethyl)dimethylchlorosilane.

4. The method for manipulating large particles on liquid-like surfaces and various solid-liquid hybrids based on pyroelectric effects according to claim 1, characterized in that... In step two, the solvent is toluene or isopropanol.

5. The method for manipulating large particles on liquid-like surfaces and various solid-liquid analogues based on pyroelectric effects according to claim 1, characterized in that... In step three, the photothermal responsive particles are one of carbon black, iron oxide nanoparticles, carbon nanotubes, graphene, and MXene.

6. The method for manipulating large particles on liquid-like surfaces and various solid-liquid hybrids based on pyroelectric effects according to claim 1, characterized in that... In step four, the power of the near-infrared light source is 300~1500 mW.

7. The method for manipulating large particles on liquid-like surfaces and various solid-liquid hybrids based on pyroelectric effects according to claim 1, characterized in that... In step five, the droplets are: electronic fluorinated liquid FC 72, electronic fluorinated liquid FC 770, electronic fluorinated liquid FC40, electronic fluorinated liquid Novec 7500, electronic fluorinated liquid Novec 7000, electronic fluorinated liquid FC 70, perfluoropolyether lubricant GPL101, n-hexane, n-heptane, n-nonane, cyclohexane, n-hexadecane, carbon tetrachloride, 1,4-dioxane, p-xylene, benzene, toluene, m-xylene, triethylamine, o-xylene, diethylamine, bromobenzene, diiodomethane, chlorobenzene, ethyl acetate, ethyl benzoate, acetic acid, methyl acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, tert-butanol, pyridine, isobutanol, 1-propanol, acetone, ethanol, hexamethylphosphoramide, N-methylpyrrolidone, methanol, nitrobenzene, ethylene glycol, acetonitrile, N,N-dimethylformamide, N,N - One or more of the following fifty solvents: dimethylacetamide, glycerol, dimethyl sulfoxide, formic acid, water, and formamide.

8. The method for manipulating large particles on liquid-like surfaces and various solid-liquid hybrids based on pyroelectric effects according to claim 1, characterized in that... In step six, the irregular shape is one of the following: cube, cylinder, triangular prism, hemisphere, sphere, irregular prism, or hollow cylinder.

9. The method for manipulating large particles on liquid-like surfaces and various solid-liquid hybrids based on pyroelectric effects according to claim 1, characterized in that... In step six, the solid substance is one or more of the following twenty solid substances: perfluoroethylene-propylene copolymer, polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, sarin resin, polymethyl methacrylate, polyacrylaldehyde, polylactic acid, epoxy resin, nylon 66, potassium permanganate, sodium chloride, soda-lime glass, silicon nitride, zirconium oxide ceramic, ferrous sulfate heptahydrate, copper, aluminum, and stainless steel.

Images