Flexible magnetic response cilia array with mechanical robustness and preparation method and application thereof

Abstract

The invention discloses a flexible magnetic response cilia array with mechanical robustness and a preparation method and application thereof. The flexible magnetic response cilia array comprises an array substrate and flexible magnetic response cilia, the array substrate comprises a substrate body and an array structure vertically arranged on the substrate body. The array structure is composed of a plurality of supporting units. The flexible magnetic response cilia vertically grow on the side walls of the supporting units and are parallel to the substrate. The invention provides a flexible magnetic response cilia array with mechanical robustness. The flexible magnetic response cilia are horizontally arranged on the side wall of the supporting unit with the mechanical strength, the cilia are hidden and protected and are not prone to being exposed to an external mechanical damage source, and the friction resistance and the abrasion resistance are improved. When the magnetic field is not applied, cilia are protected; when a vertical magnetic field is applied, the cilia can stand up and exceed the supporting units, and surface property regulation and control such as wettability regulation, liquid drop impact dynamic regulation and control and micro-object control are achieved.

Description

Technical Field

[0001] The present invention relates to the technical fields of functional materials and microfluidics / object control technologies, and particularly relates to a flexible magnetic-responsive cilia array with mechanical robustness, and a preparation method and application thereof. Background Art

[0002] In recent years, artificial cilia have been widely studied and applied in multiple fields due to their flexibility and stimulus responsiveness, such as micro-robots, self-cleaning surfaces, microfluidic devices, etc. However, existing stimulus-responsive flexible cilia still face many technical challenges, especially in dealing with mechanical damage (such as friction, wear, etc.). The main problems of the existing technologies are as follows: 1. Lack of mechanical strength of materials: Most of the existing flexible and stimulus-responsive micro-cilia are made of flexible materials (such as polymers), and these materials themselves have poor performance in resisting mechanical damage and cannot effectively cope with external friction or wear. 2. Limitations in the arrangement of cilia: In the existing technologies, most flexible cilia are vertically arranged on the substrate and directly exposed to external mechanical damage sources. This arrangement makes the cilia vulnerable to direct external forces such as friction and collision, resulting in insufficient durability and robustness, and it is particularly easy to be damaged in practical applications. To overcome these problems, various explorations have been carried out on the preparation technology of flexible magnetic-responsive cilia. Currently, two common preparation methods include: Self-assembly of iron powder aerosol in a magnetic field: This method sprays an aerosol containing iron powder onto the substrate and makes it self-assemble into micro-cilia perpendicular to the substrate under the action of a vertical magnetic field. After heating and curing, these cilia not only have flexibility but also can provide magnetic responsiveness through iron particles. However, since these cilia grow directly perpendicular to the substrate, they cannot avoid being exposed to external mechanical damage and are extremely vulnerable to damage by friction and wear. There is also a method using the replication and casting method: This method manufactures a micropore array on the mold, and after hydrophobic treatment of the mold, a mixture of PDMS, curing agent, and iron powder is used for replication to prepare micro-cilia, forming flexible and magnetic-responsive cilia. Similarly, the cilia array prepared by this method is still exposed to the external environment and is easily damaged by external forces.

[0003] Therefore, the existing flexible magnetic-responsive cilia have significant deficiencies in practical applications, especially in scenarios that require high durability and robustness, and are easily damaged by mechanical external forces. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention proposes a flexible magnetoresponsive cilia array with mechanical robustness. By horizontally arranging the flexible magnetoresponsive cilia on the sidewalls of a support unit with mechanical strength, the height of the cilia is lower than that of the support unit, and they are hidden and protected by the support unit, making it difficult to be exposed to external mechanical damage sources, thus enhancing the ability to resist friction and wear. When no magnetic field is applied, the cilia are protected; when a magnetic field perpendicular to the substrate is applied, the cilia can stand up and extend beyond the support unit, realizing the regulation of surface properties, such as wettability adjustment, dynamic regulation of droplet impact, and manipulation of micro-objects.

[0005] The present invention also provides a method for preparing a flexible magnetoresponsive cilia array with mechanical robustness.

[0006] The present invention also provides the application of a flexible magnetoresponsive cilia array with mechanical robustness in the fields of self-cleaning, microfluidic control, or micro-object manipulation.

[0007] According to an embodiment of the first aspect of the present invention, a flexible magnetoresponsive cilia array with mechanical robustness is proposed, comprising: an array substrate and flexible magnetoresponsive cilia;

[0008] The array substrate includes a substrate and an array structure vertically arranged on the substrate, and the array structure is composed of a plurality of support units;

[0009] The flexible magnetoresponsive cilia grow vertically on the sidewalls of the support unit and are parallel to the substrate.

[0010] According to the embodiment of the first aspect of the present invention, it has at least the following beneficial effects:

[0011] The present invention provides a flexible magnetic response cilia array with mechanical robustness. The core innovation lies in growing the flexible magnetic response cilia vertically on the sidewall of the support unit and parallel to the substrate. This design enables the cilia to be hidden within the array structure when not in use, and when needed, they can be extended from the array structure and protrude above the top of the array structure under the guidance of a magnetic field. The beneficial effects of the present invention are mainly reflected in the following aspects: 1. Mechanical protection performance: When no magnetic field is applied or the applied magnetic field direction is parallel to the cilia, the cilia are perpendicular to the sidewall of the support unit and parallel to the substrate, hiding them in the gaps between the support unit groups. This structural design allows the mechanical damage source to only contact the top of the support unit group, and the high mechanical strength of the support unit group can effectively prevent the cilia from being directly mechanically damaged, thereby significantly enhancing the mechanical robustness and service life of the cilia. 2. Controllability of surface and interface functions: When a magnetic field not parallel to the substrate is applied, the magnetic response cilia will be aligned along the magnetic field direction, and can extend from the array structure and protrude above the top of the array structure. This controllable extension mechanism enables the cilia array to achieve dynamic regulation of surface properties, such as wettability adjustment, dynamic regulation of droplet impact, and manipulation of micro-objects, greatly expanding its application scenarios and functionality. By growing the flexible magnetic response cilia vertically on the sidewall of the support unit and parallel to the substrate, the present invention not only realizes the hiding and extension functions of the cilia, but also simplifies the structural design, improving the practicality and operability of the device. This innovative structure reduces the manufacturing and maintenance costs while ensuring functionality, and has significant industrial application value.

[0012] According to some embodiments of the present invention, the width of the support unit is 0.1 - 0.3 mm, the height is 0.2 - 0.8 mm, and the center distance between the support units is 0.5 - 3 mm.

[0013] Under the above conditions, the flexibility of the cilia array can be enhanced, enabling effective directional adjustment and growth under different magnetic field conditions. An appropriate center distance ensures: 1. Sufficient cilia length, enabling obvious deformation and extension from the support unit under the action of the magnetic field, thereby realizing functions such as wettability, dynamic regulation of droplet impact, and manipulation of micro-objects; 2. External mechanical damage sources cannot enter the gaps between the support units and cannot damage the cilia, thereby endowing the cilia array with mechanical robustness.

[0014] According to an embodiment of the second aspect of the present invention, a preparation method of a flexible magnetic response cilia array with mechanical robustness is provided, including: taking an array substrate, and spraying an aerosol containing ferromagnetic particles on the array substrate under the guidance of a magnetic field for self-assembly molding;

[0015] The magnetic induction line direction of the magnetic field is parallel to the substrate.

[0016] On the one hand, traditional cilia preparation methods usually require complex external force intervention (such as mechanical imprinting, template-assisted, etc.) or multiple processing steps to achieve the ordered arrangement of cilia. However, in the present invention, the self-assembly of ferromagnetic particle aerosol is guided by a magnetic field, which simplifies the preparation process, avoids the high requirements for equipment and environment in traditional methods, thereby reducing costs and improving preparation efficiency. On the other hand, the aerosol of ferromagnetic particles under the guidance of a magnetic field will gather and grow along the horizontal magnetic induction line direction on the side wall of the support unit, and the growth direction is parallel to the substrate. Therefore, the cilia will not protrude from the array structure and protrude above the top of the array structure at this time, but are completely located within the side wall gap of the array structure. This state avoids the cilia from being damaged by the external environment or mechanically during normal use or storage. At this time, any mechanical damage source can only contact the top of the support unit in the array structure. Since the support unit has high mechanical strength, it can effectively resist external damage and ensure that the cilia are not damaged. Therefore, the mechanical damage source is prevented from directly contacting the cilia, protecting the integrity of the magnetoresponsive flexible cilia.

[0017] According to some embodiments of the present invention, the preparation raw materials of the aerosol of ferromagnetic particles include: ferromagnetic particles, cross-linked polymer precursors, and curing agents.

[0018] According to some embodiments of the present invention, the ferromagnetic particles include at least one of carbonyl iron powder particles, neodymium iron boron particles, and magnetite particles.

[0019] According to some embodiments of the present invention, the cross-linked polymer precursors include at least one of polydimethylsiloxane, polyimide, and polyurethane elastomer.

[0020] According to some embodiments of the present invention, the diameter of the ferromagnetic particles is 3-10 μm.

[0021] According to some embodiments of the present invention, the preparation raw materials of the aerosol of ferromagnetic particles further include organic solvent 1.

[0022] According to some embodiments of the present invention, the organic solvent 1 includes at least one of chloroform, dichloromethane, and toluene.

[0023] According to some embodiments of the present invention, the weight ratio of the organic solvent 1, the ferromagnetic particles, the cross-linked polymer precursors, and the curing agents is 3:1-2:1:0.05-0.2.

[0024] According to some embodiments of the present invention, the preparation method of the spraying mixture of the aerosol of ferromagnetic particles includes: adding ferromagnetic particles into organic solvent 1, performing ultrasonic treatment for 30-40 min, and then adding cross-linked polymer precursors and curing agents, and stirring for 30-40 min.

[0025] The curing agent in the present invention includes a curing agent compatible with PDMS.

[0026] According to some embodiments of the present invention, the material of the substrate includes at least one of aluminum, copper, and stainless steel.

[0027] According to some embodiments of the present invention, the preparation method further includes: spraying a superhydrophobic modification solution onto the flexible magnetoresponsive cilia array.

[0028] According to some embodiments of the present invention, the raw materials for preparing the superhydrophobic modification solution include: fluorosilane, hydrophobic nanoparticles, and silane coupling agent.

[0029] According to some embodiments of the present invention, the raw materials for preparing the superhydrophobic modification solution further include organic solvent 2, and the organic solvent 2 includes at least one of ethanol, toluene, n-hexane, and cyclohexane.

[0030] According to some embodiments of the present invention, the fluorosilane includes at least one of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, and trimethoxy(1H,1H,2H,2H-perfluoro-1-octyl)silane.

[0031] According to some embodiments of the present invention, the hydrophobic nanoparticles include at least one of silica, titanium dioxide, and aluminum oxide.

[0032] According to some embodiments of the present invention, the silane coupling agent includes one of 3-aminopropyltriethoxysilane and 3-(2;3-epoxypropoxy)propyltrimethoxysilane.

[0033] According to some embodiments of the present invention, by weight, the mass ratio of the fluorosilane, the hydrophobic nanoparticles, the silane coupling agent, and the organic solvent 2 is 1-2:1-3:1:50.

[0034] According to some embodiments of the present invention, the spraying of the superhydrophobic modification solution onto the flexible magnetoresponsive cilia array includes: mixing the fluorosilane, the hydrophobic nanoparticles, the silane coupling agent, and the organic solvent 2, mechanically stirring at room temperature for 15-20 min, then performing ultrasonic treatment for 15-20 min to obtain a solution, and spraying the prepared solution onto the flexible magnetoresponsive cilia array with mechanical robustness and then heating at 80-90 °C for 1-2 h.

[0035] According to the embodiments of the third aspect of the present invention, an application of a flexible magnetoresponsive cilia array with mechanical robustness in the fields of self-cleaning, microfluidic control, or micro-object manipulation is proposed.

[0036] According to some embodiments of the present invention, the method of the application includes: taking the flexible magnetoresponsive cilia array with mechanical robustness, and under the guidance of a magnetic field, extending the cilia out of the array structure along the magnetic induction line direction and protruding above the top of the array structure.

[0037] The flexible magnetoresponsive cilia array in the present invention has high mechanical robustness and can achieve highly controllable morphological changes under the guidance of an external magnetic field. Specifically, the cilia will stand up along the magnetic induction line direction under the action of an external magnetic field, extend out of the array structure and protrude above the top of the array structure, thereby affecting the contact angle of droplets, wetting behavior, realizing the directional manipulation of droplets, regulating surface wettability, and influencing the impact dynamics of droplets and other applications, which is of great significance in self-cleaning, anti-pollution, anti-fouling coatings, and microfluidic technology. Since the cilia can freely extend independently of the substrate under the action of a magnetic field, it further realizes the rapid regulation and dynamic response of surface properties, providing users with a higher degree of freedom of operation in practical applications.

[0038] Unless otherwise specified, the "about" in the present invention actually means that the allowable error is within the range of ±2%. For example, about 100 is actually 100 ± 2% × 100.

[0039] Unless otherwise specified, the "between... and..." in the present invention includes the endpoints. For example, "between 2 and 3" includes the endpoint values 2 and 3.

[0040] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification or be understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0042] Figure 1 Schematic diagram of the "mechanical robustness" principle of the flexible magnetoresponsive cilia array with mechanical robustness prepared for Example 1;

[0043] Figure 2 Schematic diagram of the preparation method of the flexible magnetoresponsive cilia array with mechanical robustness for Example 1;

[0044] Figure 3 Morphology regulation test diagram of the flexible magnetoresponsive cilia array with mechanical robustness prepared for the example in a magnetic field;

[0045] Figure 4 Schematic diagram of the function of the flexible magnetoresponsive cilia array with mechanical robustness prepared for the example to regulate the impact dynamics of droplets. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] In the following, the concept and technical effects of the present invention will be clearly and completely described in combination with the embodiments to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0047] In the description of the present invention, the description of reference terms such as "an embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0048] Moreover, the quality of the preparation raw materials is only used to represent the ratio and does not represent the actual quality. In actual production, the production volume can be scaled up or down proportionally according to requirements.

[0049] An embodiment of the first aspect of the present invention provides a flexible magnetoresponsive cilia array with mechanical robustness, including: an array substrate and flexible magnetoresponsive cilia;

[0050] The array substrate includes a substrate and an array structure vertically arranged on the substrate, and the array structure is composed of a plurality of support units;

[0051] The flexible magnetoresponsive cilia grow vertically on the side walls of the support units and are parallel to the substrate.

[0052] Combined with the embodiments of the first aspect of the present invention, it has at least the following beneficial effects:

[0053] The flexible magnetic response cilia array with mechanical robustness of the present invention can effectively resist mechanical external force damage. When the flexible magnetic response cilia are not needed, they can be hidden in the array structure, and when needed, they can be exposed from the frame by magnetic field guidance. The core innovation of the present invention is to grow the flexible magnetic response cilia vertically on the side wall of the support unit and parallel to the substrate. Specifically: (1) When no magnetic field is applied or the direction of the applied magnetic field is parallel to the substrate, the cilia growing vertically on the side wall of the support unit and parallel to the substrate can be hidden in the gaps of the support unit group. Therefore, the mechanical damage source can only contact the top of the support unit group, and due to the mechanical strength of the support unit group, the cilia can be effectively protected from direct mechanical damage, thus providing protection for the cilia; (2) Under the structure of the flexible magnetic response cilia array with mechanical robustness described above, when a magnetic field not parallel to the substrate is applied, the magnetic response cilia will be arranged in a direction along the magnetic field direction, protruding from the array structure and protruding above the top of the array structure, and then the surface properties can be regulated, such as wettability adjustment, dynamic regulation of droplet impact, and manipulation of micro-objects, etc.

[0054] An embodiment of the second aspect of the present invention provides a preparation method of a flexible magnetic response cilia array with mechanical robustness, including: taking an array substrate, and spraying an aerosol containing ferromagnetic particles on the array substrate under magnetic field guidance for self-assembly molding; the magnetic induction line direction of the magnetic field is parallel to the substrate.

[0055] Combined with the embodiment of the second aspect of the present invention, it has at least the following beneficial effects:

[0056] On the one hand, traditional cilia preparation methods usually require complex external force intervention (such as mechanical imprinting, template assistance, etc.) or multiple processing steps to achieve the ordered arrangement of cilia. However, the present invention simplifies the preparation process by guiding the self-assembly of the aerosol through a magnetic field, avoiding the high requirements for equipment and environment in traditional methods, thus reducing costs and improving preparation efficiency. On the other hand, the aerosol containing ferromagnetic particles under magnetic field guidance will aggregate and grow on the side wall of the support unit along the horizontal magnetic induction line direction, and finally form cilia. The direction of the cilia is parallel to the substrate. Therefore, the cilia will not protrude from the array structure and protrude above the top of the array structure at this time, but are completely located in the side wall gaps of the array structure. This state avoids the cilia from being damaged by the external environment or machinery during normal use or storage. At this time, any mechanical damage source can only contact the top of the support unit in the array structure. Due to the high mechanical strength of the support unit, it can effectively resist external damage and ensure the safety of the cilia is not damaged. Therefore, the mechanical damage source is prevented from directly contacting the cilia, protecting the integrity of the magnetic response flexible cilia.

[0057] Embodiments of the third aspect of the present invention provide applications of a flexible magnetoresponsive cilia array with mechanical robustness in the fields of self-cleaning, microfluidic control, or micro-object manipulation.

[0058] Combined with the embodiments of the third aspect of the present invention, there are at least the following beneficial effects:

[0059] The flexible magnetoresponsive cilia array in the present invention has high mechanical robustness and can achieve highly controllable morphological changes under the guidance of an external magnetic field, thereby affecting the contact angle of droplets, wetting behavior, realizing directional manipulation of droplets, adjusting surface wettability, and influencing the impact dynamics of droplets. It has important significance in self-cleaning, anti-pollution, anti-fouling coatings, and microfluidic technology.

[0060] The preparation method of the array substrate in the present invention is as follows: Use an infrared laser to process a sheet matrix with a thickness of 0.1 mm, a width of 1.2 mm, a height of 0.55 mm, and a center distance of 1 mm on a 1 mm thick aluminum plate as the substrate. After ultrasonic cleaning the substrate with 95% alcohol for 10 minutes, dry it.

[0061] Unless otherwise specified, the array substrates used in the specific embodiments are all from this example.

[0062] Moreover, the mass of the preparation raw materials is only used to represent the ratio and does not represent the actual mass. In actual production, the production volume can be scaled up or down proportionally according to requirements.

[0063] Example 1

[0064] S1. In this example, a flexible magnetoresponsive cilia array with mechanical robustness was prepared. Specifically, the substrate with the sheet matrix was placed in a 450 mT magnetic field horizontal to the substrate, that is, the magnetic induction lines perpendicularly passed through each sheet structure. An aerosol containing ferromagnetic particles was atomized by a spray gun with a nozzle diameter of 0.3 mm and sprayed vertically onto the substrate. The aerosol containing ferromagnetic particles would self-assemble on the side walls of the sheet array under the action of the horizontal magnetic field to form a flexible magnetoresponsive cilia array growing perpendicular to the side walls of the sheet array. The substrate with the sheet array and the magnet were placed in an oven and heated at 60 °C for 1 h, then the magnet was removed and heated at 120 °C for 1 h. Finally, a magnetically controlled cilia array with mechanical robustness was obtained;

[0065] S2. Add 0.6 g of 96% 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS-17), 0.6 g of hydrophobic fumed silica with a particle size of 7 nm to 40 nm, and 0.6 g of 98% 3-aminopropyltriethoxysilane (KH550) into 30 g of 95% ethanol. Stir mechanically at room temperature for 15 min, then sonicate for 15 min. Spray the prepared solution onto the mechanically robust flexible magnetoresponsive cilia array in S1, and then heat at 80 °C for 1 h to modify the magnetoresponsive cilia array into a superhydrophobic surface.

[0066] The preparation method of the aerosol containing ferromagnetic particles is as follows:

[0067] Add 30 g of carbonyl iron powder with a particle size of 5 μm into 60 g of toluene and sonicate for 30 minutes. Then add 20 g of SYLGARD 184 base liquid and 2 g of SYLGARD 184 curing agent, and stir for 30 minutes.

[0068] Figure 1 Schematic diagram of the "mechanical robustness" principle of the mechanically robust flexible magnetoresponsive cilia array prepared in Example 1: Figure 1 a in is a schematic diagram of the mechanically robust magnetoresponsive cilia array;

[0069] Figure 1 b in is a schematic diagram of the mechanical robustness principle of the magnetically controlled microcilia: The magnetically controlled microcilia only grow horizontally on the side walls of the vertical support units, and the mechanical damage source can only touch the top of the support units and cannot enter the gaps of the array structure composed of multiple support units, thereby protecting the magnetically controlled microcilia from mechanical damage.

[0070] Figure 2 Schematic diagram of the preparation method of the mechanically robust flexible magnetoresponsive cilia array of Example 1.

[0071] Example 2

[0072] In this example, a mechanically robust flexible magnetoresponsive cilia array was prepared. The difference between this example and Example 1 is that the superhydrophobic modification in step S2 was not carried out. Specifically:

[0073] In this example, a flexible magnetoresponsive cilia array with mechanical robustness was prepared as follows: A substrate with a sheet matrix was placed in a 450 mT magnetic field parallel to the substrate, i.e., the magnetic induction lines perpendicularly passed through each sheet structure. An aerosol containing ferromagnetic particles was atomized by a spray gun with a nozzle diameter of 0.3 mm and sprayed onto the substrate. Under the action of the horizontal magnetic field, the aerosol containing ferromagnetic particles self-assembled on the sidewalls of the sheet array, forming a flexible magnetoresponsive cilia array growing perpendicular to the sidewalls of the sheet array. The substrate with the sheet array and the magnet were placed in an oven and heated at 60 °C for 1 h, then the magnet was removed and heated at 120 °C for another 1 h. Finally, a magnetically controlled cilia array with mechanical robustness was obtained.

[0074] Example 3

[0075] In this example, a flexible magnetoresponsive cilia array with mechanical robustness was prepared. The difference between this example and Example 1 is that the crosslinked polymer precursor is polyimide, and the other conditions are the same.

[0076] Example 4

[0077] In this example, a flexible magnetoresponsive cilia array with mechanical robustness was prepared. The difference between this example and Example 1 is that the support units on the array substrate are a square hole array, and the other conditions are the same. The flexible magnetoresponsive cilia prepared in this example will grow on the hole walls perpendicular to the magnetic induction lines, and no cilia will grow on the hole walls parallel to the magnetic induction lines.

[0078] Comparative Example 1

[0079] In this example, a flexible magnetoresponsive cilia array with mechanical robustness was prepared. The difference between this example and Example 1 is that the direction of the magnetic induction lines is perpendicular to the substrate, and the other conditions are the same. Specifically:

[0080] S1. A substrate with a sheet matrix was placed in a 450 mT magnetic field perpendicular to the substrate. An aerosol containing ferromagnetic particles was atomized by a spray gun with a nozzle diameter of 0.3 mm and sprayed onto the substrate. Under the action of the perpendicular magnetic field, the aerosol containing ferromagnetic particles self-assembled on the top of the sheet array and the substrate, forming a flexible magnetoresponsive cilia array growing perpendicular to the substrate. The substrate with the sheet array and the magnet were placed in an oven and heated at 60 °C for 1 h, then the magnet was removed and heated at 120 °C for another 1 h. Finally, a magnetically controlled cilia array growing vertically on the sheet array and the substrate was obtained.

[0081] S2. Add 0.6 g of 96% 1H,1H,2H,2H - perfluorodecyltriethoxysilane (FAS - 17), 0.6 g of hydrophobic fumed silica with a particle size of 7 nm - 40 nm, and 0.6 g of 98% 3 - aminopropyltriethoxysilane (KH550) into 30 g of 95% ethanol. Stir mechanically at room temperature for 15 min, then ultrasonicate for 15 min. Spray the prepared solution onto the magnetoresponsive cilia array in S1, and then heat at 80 °C for 1 h to modify the magnetoresponsive cilia array into a superhydrophobic surface.

[0082] The preparation method of the aerosol containing ferromagnetic particles is as follows:

[0083] Add 30 g of carbonyl iron powder with a particle size of 5 μm into 60 g of toluene and ultrasonicate for 30 minutes. Then add 20 g of SYLGARD184 base liquid and 2 g of SYLGARD 184 curing agent, and stir for 30 minutes.

[0084] The cilia array prepared in Comparative Example 1 will not be hidden in the gaps of the support unit like that in Example 1, but is exposed to a greater risk of mechanical damage, resulting in the mechanical robustness of the cilia array being affected. It is easily affected by external forces, causing the cilia to bend or break, thus affecting the mechanical stability of the entire array.

[0085] Application Example 1

[0086] This application example is a schematic diagram of the switching between the "flexible magnetoresponsive cilia array with mechanical robustness" prepared in Example 1 to achieve its "mechanical robustness" and "other applications": As shown in Figure 3 a: When a horizontal magnetic field is applied to the flexible magnetoresponsive cilia array with mechanical robustness, or when no magnetic field is applied, the cilia are horizontally arranged inside the vertical sub - millimeter frame. At this time, the flexible magnetoresponsive cilia are hidden and protected, and have mechanical robustness;

[0087] As shown in Figure 3 b: When a magnetic field perpendicular to the substrate is applied to the flexible magnetoresponsive cilia array with mechanical robustness, the cilia stand up perpendicular to the substrate along the direction of the magnetic induction line, and its height extends out of the array structure and protrudes above the top of the array structure, and can be used to achieve functions such as surface wettability regulation.

[0088] When a horizontal magnetic field is applied to the mechanically robust flexible magnetoresponsive cilia array prepared in Example 2, or when no magnetic field is applied, the cilia are horizontally arranged inside the vertical submillimeter frame. At this time, the flexible magnetoresponsive cilia are hidden and protected and have mechanical robustness. When a magnetic field perpendicular to the substrate is applied to the mechanically robust flexible magnetoresponsive cilia array, the cilia stand up perpendicular to the substrate along the direction of the magnetic induction line, and their height extends out of the array structure and protrudes above the top of the array structure, and thus can be used to realize functions such as surface wettability regulation.

[0089] When a horizontal magnetic field is applied to the mechanically robust flexible magnetoresponsive cilia array prepared in Example 3, or when no magnetic field is applied, the cilia are horizontally arranged inside the vertical submillimeter frame. At this time, the flexible magnetoresponsive cilia are hidden and protected and have mechanical robustness. When a magnetic field perpendicular to the substrate is applied to the mechanically robust flexible magnetoresponsive cilia array, the cilia stand up perpendicular to the substrate along the direction of the magnetic induction line, and their height extends out of the array structure and protrudes above the top of the array structure, and thus can be used to realize functions such as surface wettability regulation.

[0090] Application Example 2

[0091] This application example is a function demonstration of the "mechanical robustness" and "other applications" of the "mechanically robust flexible magnetoresponsive cilia array" prepared in the embodiments: Figure 4 In a, a droplet is released from a height of 6 cm and impacts the magnetoresponsive cilia array in Example 1, and a horizontal magnetic field is applied. Figure 4 In b, a droplet is released from a height of 6 cm and impacts the magnetoresponsive cilia array in Example 1, and a vertical magnetic field is applied. The contact times of the droplet with the substrate are 22.6 ms and 8.4 ms respectively, which reflects the regulation of the droplet impact dynamics on the surface of the mechanically robust flexible magnetoresponsive cilia array. Figure 4 In c, the droplet moves directionally. When the droplet impacts the substrate, a magnetic field inclined at 45° is applied to the substrate, and the droplet shows a phenomenon of directional bouncing to the right; the above method can guide the droplet to move in a specific direction, change the shape of the droplet, regulate the interaction force between the droplet and the surface, etc. In the fields of microfluidic sensors and microfluidic devices, the cilia array can regulate the fluid flow path through magnetic field control to achieve high-precision fluid operation; in addition, in the field of micro-object manipulation, these magnetoresponsive cilia can move, grasp or operate micro-objects under the action of an external magnetic field. The directional change of the cilia array can be used to precisely manipulate micro-particles or micro-objects and play an important role in applications such as micro-mechanical systems, nano-robots, and microfluidic devices.

[0092] Figure 4In d, a scalpel was used to scratch the surface of the mechanically robust flexible magnetoresponsive cilia array. Only the top of the flake array was worn, while the cilia were hardly damaged, demonstrating the mechanical robustness of the cilia array; Figure 4 In e, after scratching the surface of the cilia array with a scalpel, a droplet was released from a height of 6 cm, hitting the scratched substrate, and a horizontal magnetic field was applied. The contact time between the droplet and the substrate was 23.6 ms. Figure 4 In f, after scratching the surface of the cilia array with a scalpel, a droplet was released from a height of 6 cm, and the contact time between the droplet and the substrate was 10.4 ms, still showing a contact time similar to that in Figure 4 a and b in, proving that the superhydrophobicity of the surface and the function of dynamically regulating droplet impact were not damaged, further demonstrating the mechanical robustness of the surface.

[0093] The present invention designed and fabricated a cilia array (Examples 1-3) that grows on the sidewall of the support unit and is parallel to the substrate. When no magnetic field is applied or a magnetic field parallel to the substrate is applied, the magnetoresponsive flexible cilia are hidden in the sidewall gap of the support unit of the array structure, and the cilia are in a static state at this time. When encountering external mechanical damage (such as friction or collision), the damage source can only contact the top of the support unit. Since the support unit has high mechanical strength and can effectively resist external damage, the magnetoresponsive flexible cilia will not be damaged, thus overcoming the problem that the cilia are vulnerable to mechanical damage. This design effectively improves the mechanical robustness of the cilia array, ensuring that the cilia are not interfered by the external environment during daily use or storage. When it is necessary to activate the flexible magnetoresponsive cilia, by adjusting the magnetic field direction, the cilia can extend from the array structure along the magnetic induction line direction and protrude above the top of the array structure. At this time, the cilia can exert their magnetoresponsive characteristics for realizing surface wettability regulation, droplet manipulation, and other functional applications. This design not only simplifies the control process of the magnetoresponsive cilia but also provides a flexible function switching ability for its application in various engineering fields.

Claims

1. A flexible magnetic-responsive cilia array with mechanical robustness, characterized in that, Comprising: An array substrate and flexible magnetoresponsive cilia; The array substrate includes a substrate and an array structure vertically arranged on the substrate, and the array structure is composed of a plurality of support units; The flexible magnetoresponsive cilia grow vertically on the side walls of the support units and are parallel to the substrate.

2. The flexible magnetic response cilia array with mechanical robustness according to claim 1, wherein The width of the support unit is 0.1 - 0.3 mm, the height is 0.2 - 0.8 mm, and the center distance between the support units is 0.5 - 3 mm.

3. A method for preparing a flexible magnetoresponsive cilia array with mechanical robustness as described in claim 1 or 2, characterized in that, Comprising: Taking an array substrate, and spraying an aerosol containing ferromagnetic particles on the array substrate under the guidance of a magnetic field for self-assembly molding; The magnetic induction line direction of the magnetic field is parallel to the substrate.

4. The preparation method of the flexible magnetoresponsive cilia array with mechanical robustness according to claim 3, characterized in that, The preparation raw materials of the aerosol containing ferromagnetic particles include: ferromagnetic particles, a cross-linked polymer precursor, and a curing agent.

5. The preparation method of the flexible magnetic response cilia array with mechanical robustness according to claim 4, characterized in that, The cross-linked polymer precursor includes at least one of polydimethylsiloxane, polyimide, and polyurethane elastomer.

6. The preparation method of the flexible magnetic response cilia array with mechanical robustness according to claim 4, characterized in that, The ferromagnetic particles include at least one of carbonyl iron powder, neodymium iron boron particles, and iron oxide particles, and the diameter of the ferromagnetic particles is 3 - 10 μm.

7. The preparation method of the flexible magnetic response cilia array with mechanical robustness according to claim 3, characterized in that, The preparation method further includes: spraying a superhydrophobic modification solution on the flexible magnetoresponsive cilia array; The preparation raw materials of the superhydrophobic modification solution include: fluorosilane, hydrophobic nanoparticles, and a coupling agent.

8. The preparation method of the flexible magnetic response cilia array with mechanical robustness according to claim 7, characterized in that, The fluorosilane includes at least one of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, and trimethoxy(1H,1H,2H,2H-perfluoro-1-octyl)silane.

9. An application of a flexible magnetoresponsive cilia array with mechanical robustness as claimed in claim 1 or 2 in the fields of self-cleaning, microfluidic control, or micro-object manipulation.

10. The application according to claim 9, characterized in that The method of the application includes: taking the flexible magnetoresponsive cilia array with mechanical robustness, and under the guidance of a magnetic field, extending the cilia out of the array structure along the magnetic induction line direction and protruding above the top of the array structure to achieve the application.

Images