Bundle-shaped magnetic photonic crystal, preparation method and application of micro-nano device of beam-shaped magnetic photonic crystal

Abstract

The invention relates to the technical field of photonic crystal materials and micro-nano devices, in particular to a beam-shaped magnetic photonic crystal, a preparation method of the beam-shaped magnetic photonic crystal and application of a micro-nano device of the beam-shaped magnetic photonic crystal. Each one-dimensional magnetic photonic nano chain is formed by assembling a plurality of magnetic nano particles into a chain, and the magnetic nano particles in the beam-shaped magnetic photonic crystal are arranged into a one-dimensional photonic crystal structure along the axial direction of the beam-shaped magnetic photonic crystal and are arranged into a two-dimensional photonic crystal structure along the radial direction of the beam-shaped magnetic photonic crystal. Compared with a single photon nanometer chain, the beam-shaped magnetic photonic crystal shows larger color spots and unique axial-radial two-way color rendering property, the photonic crystal structural color can be displayed in the axial dimension and the radial dimension, and the beautiful structural color is displayed.

Description

Technical Field

[0001] This invention relates to the technical field of photonic crystal materials and micro / nano devices, specifically to a bundled magnetic photonic crystal, its preparation method, and its application in micro / nano devices. Background Technology

[0002] Magnetic photonic crystals, as an important branch of photonic crystals, have become core materials for precisely constructing ordered photonic crystal structures due to their "contactless, rapidly switchable" magnetic field control characteristics and precise control capabilities. Their core advantage lies in the fact that, without the need for complex templates or chemical modifications, magnetic nanoparticles can be driven to align precisely by controlling the strength, direction, and duration of the magnetic field, achieving dynamic adjustment of the assembled structure and precise control of the photonic bandgap. Magnetic photonic crystals demonstrate unique value in fields such as magnetically driven optical devices, intelligent anti-counterfeiting, and color displays.

[0003] By controlling the concentration and magnetic field strength of magnetic colloidal nanoparticles, the assembled structure can evolve from one-dimensional chain-like photonic crystal structures to bundle-like photonic crystal structures, two-dimensional sheet-like photonic crystal structures, and three-dimensional opal photonic crystal structures. Based on hydrogen bond-induced template technology and sol-gel technology, researchers successfully encapsulated and fixed one-dimensional chain-like photonic crystal structures assembled from magnetic colloidal nanoparticles, obtaining one-dimensional (1D) photonic nanochains with pod-like structures, including flexible photonic nanochains encapsulated by responsive gel shells and hard photonic nanochains encapsulated by inorganic shells such as silica. Compared to magnetic photonic crystal liquids composed of magnetic colloidal nanoparticles, photonic nanochains possess stable photonic crystal structures and exhibit more sensitive magnetic susceptibility and magnetic field actuation capability.

[0004] Bundle photonic crystal structures are further assembled from chain photonic crystal structures. Compared to single photonic nanochains, bundle photonic crystals are expected to exhibit biaxial display effects along both the axial and radial directions, as well as larger color spots. Simultaneously, they not only retain the magnetic field drivability of photonic nanochains but also possess greater mechanical strength. These characteristics make them suitable as magnetically driven micro / nano devices for the visualization and unblocking of micro / nano channels, showing significant application prospects in microfluidic processing and thrombolytic robotics. However, while bundles of magnetic colloidal particles have been developed, the development of bundle magnetic photonic crystal materials has not yet been reported.

[0005] In summary, current photonic crystal materials still have significant shortcomings in multi-dimensional structural design, integration of magnetic response characteristics, and the realization of simplified fabrication processes. Therefore, developing a bundled magnetic photonic crystal that combines axial-radial bidirectional color rendering, excellent magnetic sensitivity, and a simple fabrication process has become a key technological breakthrough direction to meet the needs of fields such as color display, high-end anti-counterfeiting, and magnetically driven micro / nano devices. Summary of the Invention

[0006] In view of this, the present invention provides a beam-shaped magnetic photonic crystal, a method for its preparation, and its application in micro / nano devices.

[0007] One of the objectives of this invention is to provide a bundled magnetic photonic crystal that has both axial and radial bidirectional color rendering properties, thereby expanding the ease of manipulation and signal recognition efficiency of magnetic photonic crystals in micro-nano scale applications.

[0008] The second objective of this invention is to provide a method for preparing a bundled magnetic photonic crystal. The magnetic nanoparticles are assembled using superparamagnetic colloidal nanoparticles as the assembly unit and silica as the shell. The bundled magnetic photonic crystal is successfully prepared by a one-step sol-gel method under the assistance of an upper magnetic field.

[0009] The third objective of this invention is to provide an application of a beam-shaped magnetic photonic crystal.

[0010] One of the technical solutions adopted to achieve the objective of this invention is: a bundled magnetic photonic crystal, wherein the bundled magnetic photonic crystal is formed by a tight stacking of multiple one-dimensional magnetic photonic nanochains and fixedly connected by silicon dioxide. Each one-dimensional magnetic photonic nanochain is assembled into a chain by multiple magnetic nanoparticles. The magnetic nanoparticles in the bundled magnetic photonic crystal are arranged in a one-dimensional photonic crystal structure along the axial direction of the bundled magnetic photonic crystal and in a two-dimensional photonic crystal structure along the radial direction of the bundled magnetic photonic crystal.

[0011] Preferably, the bundled magnetic photonic crystal comprises 4-15 one-dimensional magnetic photonic nanochains. If the number of one-dimensional magnetic photonic nanochains is too small, it cannot be assembled into a bundled magnetic photonic crystal; if the number of one-dimensional magnetic photonic nanochains is too large, the prepared bundled magnetic photonic crystal will lose the optical properties of a photonic crystal.

[0012] In the bundled magnetic photonic crystal of the present invention, multiple magnetic photonic nanochains are arranged in a close-packed manner.

[0013] Preferably, the magnetic nanoparticles contain at least one magnetic element selected from iron, cobalt, and nickel, and have a particle size of 80-200 nm.

[0014] Preferably, the bundled magnetic photonic crystal exhibits the structural color of a photonic crystal along both the axial and radial directions.

[0015] Here, the axial direction is the direction along the central axis of the bundled magnetic photonic crystal, and the radial direction is the direction perpendicular to the axial direction.

[0016] Preferably, the bundled magnetic photonic crystal of the present invention can exhibit the structural color of a photonic crystal along the axial direction in a magnetic field, and can exhibit the structural color of a photonic crystal along the radial direction under an optical microscope.

[0017] The technical solution adopted to achieve the second objective of the present invention is: a method for preparing the aforementioned beam-shaped magnetic photonic crystal, comprising the following steps: (1) dispersing superparamagnetic colloidal nanoparticles in a polar solvent, adding a silicon source and a catalyst and mixing them evenly to form a prepolymer solution; (2) Apply a magnetic field above the prepolymer liquid and let it stand to react. After the reaction is completed, clean and remove impurities to obtain the bundled magnetic photonic crystal.

[0018] Preferably, in step (1), the superparamagnetic colloidal nanoparticles contain at least one magnetic element selected from iron, cobalt, and nickel, have a particle size of 80-200 nm, and have a concentration of 0.4-2.0 mg / mL in the prepolymer solution.

[0019] Preferably, in step (1), the polar solvent is a mixture of ethanol and water, with a volume ratio of ethanol to water of 8:2-4:6. For example, 8:2, 7:3, 6:4, 5:5, 4:6.

[0020] Preferably, in step (1), the silicon source includes at least one of tetraethyl orthosilicate, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, silicon tetrachloride, and methyl orthosilicate, and the concentration in the prepolymer solution is 0.08-0.20 mmol / mL. Preferably, in step (1), the catalyst includes at least one of ammonia, sodium hydroxide, potassium hydroxide, organic amine, polyacrylic acid, hydrochloric acid, and acetic acid, and the molar ratio of the catalyst to the silicon source is 2:5-2:1.

[0021] Preferably, in step (1), superparamagnetic colloidal nanoparticles are dispersed in a polar solvent, and a silicon source and catalyst are added. The mixture is then ultrasonically mixed in an ice-water bath to form a prepolymer solution. This invention uses an ice-water bath to prevent premature hydrolysis of the silicon source during the mixing of the prepolymer solution.

[0022] Preferably, in step (2), the strength of the magnetic field is 300-600 Gs; the reaction time is 7-20 min; and the reaction temperature is 5-30℃.

[0023] The third objective of this invention is achieved through the following technical solution: an application of the aforementioned beam magnetic photonic crystal, which is used in the fields of color display, drug carrier, anti-counterfeiting, or magnetic drive motor micro-nano devices.

[0024] The beneficial effects of this application are as follows: Compared to single photonic nanochains, the bundled magnetic photonic crystal of the present invention exhibits larger color spots and unique axial-radial bidirectional color rendering, displaying photonic crystal structural colors in both axial and radial dimensions, thus displaying beautiful structural colors.

[0025] The bundled magnetic photonic crystal of the present invention has excellent magnetic sensitivity, which expands the ease of manipulation and signal recognition efficiency of magnetic photonic crystals in micro-nano scale applications.

[0026] The bundled magnetic photonic crystal of this invention displays the structural color of a one-dimensional photonic crystal along its axial direction; the structural color in the axial direction can be observed with the naked eye by applying a magnetic field. It also displays the structural color of a two-dimensional photonic crystal radially; the radial structural color can be observed under an optical microscope without applying a magnetic field.

[0027] The preparation method of this invention leverages the integrated coupling effect of one-dimensional photonic crystal structures: by combining a one-step sol-gel method with anti-gravity magnetic assembly technology, one-dimensional magnetic photonic crystal chains are assembled and arranged and integrated in an orderly manner according to a specific period under the guidance of a magnetic field, forming independent micro- and nano-scale nanobundle structures, which are then fixed with silica. The preparation method is simple and easy to control.

[0028] The bundled magnetic photonic crystal of the present invention can be applied to the fields of micro and nano devices such as color displays, anti-counterfeiting, drug carriers, and magnetic drive motors. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the fabrication principle of the bundled magnetic photonic crystal obtained in Example 1. Figure 2 The image shows a scanning electron microscope image of the bundled magnetic photonic crystal obtained in Example 1. Figure 3 This is an optical microscope image of the bundled magnetic photonic crystal obtained in Example 1 without an applied magnetic field; Figure 4 Transmission electron microscopy image of the bundled magnetic photonic crystal obtained in Example 1; Figure 5 FT of the initial colloidal nanoparticles (Fe3O4@PVP) and the resulting bundled magnetic photonic crystals (Fe3O4@PVP@SiO2 nanobundles) used in Example 1 IR spectrum; Figure 6 Thermogravimetric curves of the initial colloidal nanoparticles (Fe3O4@PVP) and the resulting bundled magnetic photonic crystals (Fe3O4@PVP@SiO2 nanobundles) used in Example 1 are shown. Figure 7 The images show the spectrum (a), optical microscope image (b), and digital photograph (c) of the bundled magnetic photonic crystal obtained in Example 1 when a magnetic field is applied in one dimension. Figure 8 The images (a) and (b) show the spectrum of the bundled magnetic photonic crystal obtained in Example 2 when a magnetic field is applied in one dimension. Figure 9The images (a) and (b) show the spectrum of the bundled magnetic photonic crystal obtained in Example 3 when a magnetic field is applied in one dimension. Figure 10 The image shows a scanning electron microscope image of the bundled magnetic photonic crystal obtained in Example 4. Figure 11 This is a scanning electron micrograph of the bundled magnetic photonic crystal obtained in Example 5; Figure 12 The image shows a scanning electron microscope image of the bundled magnetic photonic crystal obtained in Example 6. Figure 13 This is an optical micrograph of the bundled magnetic photonic crystal obtained in Example 6 without an applied magnetic field; Figure 14 This is a scanning electron micrograph of the bundled magnetic photonic crystal obtained in Example 7; Figure 15 This is a scanning electron micrograph of the bundled magnetic photonic crystal obtained in Example 8; Figure 16 This is an optical microscope image of the bundled magnetic photonic crystal obtained in Example 8 without an applied magnetic field; Figure 17 This is a scanning electron micrograph of the bundled magnetic photonic crystal obtained in Example 9; Figure 18 A scanning electron microscope image of the bundled magnetic photonic crystal obtained in Example 10; Figure 19 The image shows a scanning electron microscope image of the bundled magnetic photonic crystal obtained in Comparative Example 1. Figure 20 The reflection spectrum of the bundled magnetic photonic crystal obtained in Comparative Example 1 is shown. Figure 21 The image shows a scanning electron microscope image of the bundled magnetic photonic crystal obtained in Comparative Example 2. Figure 22 The image shows a scanning electron microscope image of the bundled magnetic photonic crystal obtained in Comparative Example 3. Figure 23 This is an optical microscope image of the bundled magnetic photonic crystal obtained in Example 1 during the process of thrombolysis using pure mechanical force. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] Figure 1 This is a schematic diagram illustrating the fabrication principle of the bundled magnetic photonic crystal obtained in this invention.

[0032] Example 1 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, tetraethyl silicate and ammonia as a catalyst were added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.3 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.5 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0033] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength 300Gs~450Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain a magnetic photonic nanobundle with a structural color of green.

[0034] Figure 2 The image shows a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. It can be seen that the product has a bundled structure, consisting of 5-10 chains, and a clear hexagonal close-packed structure can be seen in the two-dimensional direction. This is the reason why it also has the structural color of a photonic crystal in the two-dimensional direction.

[0035] Figure 3 This is an optical microscope image of the bundled magnetic photonic crystal obtained in this embodiment without an applied magnetic field. Green structural color spots can be observed in the two-dimensional direction, which can be observed under a microscope without applying a magnetic field. This is because the particles have a periodic structure in the two-dimensional direction, forming a partial photonic band gap, thus reflecting some of the photonic crystal structural color spots.

[0036] Figure 4 The image shown is a transmission electron micrograph of the bundled magnetic photonic crystal obtained in this embodiment, in which a distinct silicon dioxide shell can be observed.

[0037] Figure 5 The Fourier transform of the initial colloidal nanoparticles (Fe3O4@PVP particles) and the resulting bundled magnetic photonic crystals (Fe3O4@PVP@SiO2 nanobundles) used in this embodiment is shown in the figure. In the IR spectrum, the characteristic peaks of Si-O and Si-O-Si appear only in the FT of bundled magnetic photonic crystals. In the IR spectrum, it was not detected in the initial colloidal nanoparticles, which indicates that the bundled magnetic photonic crystal was obtained by coating the bundled colloidal nanoparticle template with silica produced by the hydrolysis of tetraethyl silicate.

[0038] Figure 6 The thermogravimetric analysis (TGA) curves of the initial colloidal nanoparticles (Fe3O4@PVP particles) and the resulting bundled magnetic photonic crystals (Fe3O4@PVP@SiO2 nanobundles) used in this embodiment are shown. It can be observed that from 0 to 200°C, the mass of the Fe3O4@PVP nanoparticles decreased by 3.34%, and the mass of the Fe3O4@PVP@SiO2 nanobundles decreased by 6.36%, due to the partial evaporation of water during heating. From 200°C to 600°C, the sample mass decreased by 9.2%, due to the combustion and decomposition of the organic component PVP in the assembly unit Fe3O4@PVP. Furthermore, TGA analysis of the Fe3O4@PVP nanoparticles revealed that the combustion and decomposition of PVP was completed between 200°C and 400°C, resulting in a mass loss of 18.29%. This indicates that the photonic crystal nanobundles obtained by coating the bundled magnetic nanoparticles Fe3O4@PVP with silica exhibit significantly improved thermal stability.

[0039] Figure 7 The images show the spectrum (a), optical microscope image (b), and digital photograph (c) of the bundled magnetic photonic crystal obtained in this embodiment when a magnetic field is applied in one dimension. From (a), it can be seen that the reflection wavelength of the bundled magnetic photonic crystal prepared in this embodiment is 550 nm, corresponding to the green structural color in (b) and (c).

[0040] Example 2 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 200 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, tetraethyl silicate and ammonia as a catalyst were added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.3 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.5 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0041] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 200 Gs~300 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain a red magnetic photonic nanobundle composed of 5-10 chains.

[0042] Figure 8The images show (a) and (b) of the beam magnetic photonic crystal obtained in this embodiment with a magnetic field applied in one dimension. From (a), it can be seen that the reflection wavelength of the beam magnetic photonic crystal prepared in this embodiment is 632 nm, corresponding to the red structural color in (b).

[0043] Example 3 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 80 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, tetraethyl silicate and ammonia as a catalyst were added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.3 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.5 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0044] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 500 Gs~600 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain a magnetic photonic nanobundle with a structural color of purple, which was composed of 5-10 chains.

[0045] Figure 9 The images show the spectrum (a) and digital photograph (b) of the bundled magnetic photonic crystal obtained in this embodiment when a magnetic field is applied in one dimension. From (a), it can be seen that the reflection wavelength of the bundled magnetic photonic crystal prepared in this embodiment is 412 nm, corresponding to the purple structural color in (b).

[0046] Example 4 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water, and then an aqueous solution of tetraethyl silicate and hydrochloric acid (HCl) was added. The mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.1 mmol / ml, the concentration of hydrochloric acid was 0.04 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.5 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0047] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 300 Gs~450 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain magnetic photonic nanobundles.

[0048] Figure 10 This is a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. As can be seen from the image, the bundled magnetic photonic crystal was successfully fabricated, and the nanobundles are composed of 6-12 chains. The bundled magnetic photonic crystal prepared in this embodiment has a reflection wavelength of 534 nm and exhibits a green structural color.

[0049] Example 5 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed together with a silicon source and a catalyst in a mixed solution of anhydrous ethanol and deionized water, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The silicon source included methyltrimethoxysilane (MTMS), and the catalyst included ammonia. The concentration of methyltrimethoxysilane in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.15 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.5 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0050] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 300 Gs~450 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain magnetic photonic nanobundles.

[0051] Figure 11 This is a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. As can be seen from the image, the bundled magnetic photonic crystal was successfully fabricated, and the nanobundles are composed of 5-10 chains. The bundled magnetic photonic crystal prepared in this embodiment has a reflection wavelength of 568 nm and exhibits a green structural color.

[0052] Example 6 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, an aqueous solution of γ-mercaptopropyltrimethoxysilane (WD-80) and polyacrylic acid was added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of γ-mercaptopropyltrimethoxysilane in the prepolymer solution was 0.11 mmol / ml, the concentration of polyacrylic acid was 0.075 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.4 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0053] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 300 Gs~450 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain magnetic photonic nanobundles.

[0054] Figure 12 This is a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. As can be seen from the image, the bundled magnetic photonic crystal was successfully fabricated, and the nanobundles are composed of 4-9 chains. The bundled magnetic photonic crystal prepared in this embodiment has a reflection wavelength of 509 nm and exhibits a green structural color.

[0055] Figure 13 This is an optical microscope image of the bundled magnetic photonic crystal obtained in this embodiment without the application of a magnetic field. It can be clearly seen from the image that the structure still exhibits a green structural color in the two-dimensional direction without the application of a magnetic field.

[0056] Example 7 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles NiFe2O4, along with a silicon source and a catalyst, were dispersed in a mixed solution of anhydrous ethanol and deionized water. The mixture was then ultrasonically mixed in an ice-water bath to form a prepolymer solution. The silicon source included tetraethyl silicate, and the catalyst was ammonia. The concentration of tetraethyl silicate in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.3 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 1 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0057] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 300 Gs~450 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain magnetic photonic nanobundles.

[0058] Figure 14 This is a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. As can be seen from the image, the bundled magnetic photonic crystal was successfully fabricated, and it consists of 7-12 chains. The bundled magnetic photonic crystal prepared in this embodiment has a reflection wavelength of 519 nm and exhibits a green structural color.

[0059] Example 8 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles CoFe2O4, a silicon source, and a catalyst were dispersed together in a mixed solution of anhydrous ethanol and deionized water, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The silicon source included tetraethyl silicate, and the catalyst included ammonia. The concentration of tetraethyl silicate in the prepolymer solution was 0.14 mmol / ml, the concentration of ammonia was 0.32 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 2 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0060] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 300 Gs~450 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain magnetic photonic nanobundles.

[0061] Figure 15 This is a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. As can be seen from the image, the bundled magnetic photonic crystal was successfully fabricated, and it consists of 10-15 chains. The bundled magnetic photonic crystal prepared in this embodiment has a reflection wavelength of 555 nm and exhibits a green structural color.

[0062] Figure 16 This is an optical microscope image of the bundled magnetic photonic crystal obtained in this embodiment without the application of a magnetic field. It can be clearly seen from the image that the structure still exhibits a green structural color in the two-dimensional direction without the application of a magnetic field.

[0063] Example 9 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, tetraethyl silicate and ammonia as a catalyst were added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.08 mmol / ml, the concentration of ammonia was 0.16 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.4 mg / ml, and the ratio of anhydrous ethanol to deionized water was 6:4.

[0064] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 300 Gs~450 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain magnetic photonic nanobundles.

[0065] Figure 17 This is a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. The bundled magnetic photonic crystal was successfully fabricated, and the nanobundles are composed of 4-9 chains. The bundled magnetic photonic crystal prepared in this embodiment has a reflection wavelength of 496 nm and exhibits a green structural color.

[0066] Example 10 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, tetraethyl silicate and ammonia as a catalyst were added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.20 mmol / ml, the concentration of ammonia was 0.40 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 1.5 mg / ml, and the ratio of anhydrous ethanol to deionized water was 7:3.

[0067] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength of 300 Gs~450 Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain magnetic photonic nanobundles.

[0068] Figure 18 This is a scanning electron microscope image of the bundled magnetic photonic crystal obtained in this embodiment. The bundled magnetic photonic crystal was successfully fabricated, and the nanobundle is composed of 10-15 chains. The bundled magnetic photonic crystal prepared in this embodiment has a reflection wavelength of 564 nm and exhibits a green structural color.

[0069] Comparative Example 1 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, tetraethyl silicate and ammonia as a catalyst were added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.3 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 3 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0070] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize it, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength 300Gs~450Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, and then washed twice with anhydrous ethanol to obtain a multilayer photonic crystal nanostructure assembled from 15-30 photonic nanochains.

[0071] Figure 19 The image shows a scanning electron microscope (SEM) image of the magnetic photonic crystal obtained in this embodiment. It can be seen that the structure of the obtained magnetic photonic crystal is a sheet-like structure assembled from more than 20 nanochains, with an aspect ratio close to 1:1. Furthermore, due to its excessive weight and excessive coating with non-magnetic silica, it has lost its magnetic drive properties and cannot be oriented by applying a magnetic field. This indicates that when the concentration of magnetic nanoparticles in the prepolymer solution exceeds 2 mg / ml, the resulting structure is not a photonic crystal nanobundle.

[0072] Figure 20 The reflection spectrum of the magnetic photonic crystal obtained in this embodiment shows that the reflection peak is almost undetectable when a magnetic field is applied. This further proves that when the concentration of magnetic nanoparticles is too high, the prepared structure is no longer a photonic crystal nanobundle.

[0073] Comparative Example 2 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed together with a silicon source and a catalyst in a mixed solution of anhydrous ethanol and deionized water, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The silicon source included tetraethyl silicate, and the catalyst included ammonia. The concentration of tetraethyl silicate in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.3 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.3 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0074] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly below a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength 300Gs~450Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, followed by washing twice with anhydrous ethanol to obtain single magnetic photonic nanochains with chain lengths all above 50 μm.

[0075] Figure 21 The image shows a scanning electron microscope (SEM) image of the bundled magnetic photonic crystals obtained in this embodiment. It can be seen from the image that the obtained magnetic photonic crystals are all single-chain structures with relatively long chain lengths, averaging over 50 μm. This indicates that when the concentration of magnetic nanoparticles in the prepolymer solution is below 0.4 mg / ml, the prepared structure is not a photonic crystal nanobundle, but rather a one-dimensional nanochain.

[0076] Comparative Example 3 A method for preparing a bundled magnetic photonic crystal includes the following steps: (1) Superparamagnetic colloidal nanoparticles Fe3O4@PVP (particle size 170 nm) were dispersed in a mixed solution of anhydrous ethanol and deionized water. Then, tetraethyl silicate and ammonia as a catalyst were added, and the mixture was ultrasonically mixed in an ice-water bath to form a prepolymer solution. The concentration of tetraethyl silicate in the prepolymer solution was 0.15 mmol / ml, the concentration of ammonia was 0.3 mmol / ml, the concentration of superparamagnetic colloidal nanoparticles in the prepolymer solution was 0.5 mg / ml, and the ratio of anhydrous ethanol to deionized water was 8:2.

[0077] (2) The prepolymer solution was transferred to a circular culture dish, briefly sonicated to homogenize, and then immediately placed directly above a circular NdFeB permanent magnet (D10×1 cm) (magnetic field strength 300Gs~450Gs). After 10 min, the reaction was stopped. The reaction solution was then centrifuged at 3000 rpm for 10 min, and then washed twice with anhydrous ethanol to obtain single magnetic photonic nanochains with chain lengths within 3-7 μm.

[0078] Figure 22The image shows a scanning electron microscope (SEM) image of the bundled magnetic photonic crystals obtained in this embodiment. It can be seen from the image that the obtained magnetic photonic crystals are all single-chain structures with relatively short chain lengths, averaging 3-7 μm. This indicates that when a downward magnetic field is used for fabrication, the resulting structure is not a photonic crystal nanobundle, but rather a one-dimensional short nanochain. This is because the attractive force between particles along the axial direction induces the particles to self-assemble into a chain structure. However, with the coating of non-magnetic SiO2, the effective magnetization of the superparamagnetic particles weakens, resulting in a decrease in the induced dipole moment u. Consequently, the attractive force between particles weakens, while the particle's own gravity strengthens. Only an upward magnetic field can ensure the linear growth of the nanobundle along the axial direction.

[0079] Application Example 1 An application of a bundled magnetic photonic crystal—purely mechanical thrombolysis—includes the following steps: (1) The ethanol solution of the bundled magnetic photonic crystal prepared in Example 1 was centrifuged at 3000 rpm for 10 min, washed twice with PBS buffer, and dispersed in PBS buffer for later use.

[0080] (2) An artificial thrombus was prepared in a microfluidic channel, completely blocking the microfluidic channel. The thrombus was then placed in a rotating magnetic field, and a bundle of magnetic photonic crystals dispersed in PBS buffer was injected into one end of the microfluidic channel. Under the rotating magnetic field, the thrombus underwent a crawling motion until it reached the vicinity of the thrombus. With the magnetic field continuously applied, a channel could be observed under an optical microscope as the artificial thrombus was opened by the magnetic photonic crystal nanobundle.

[0081] Figure 23 This is an optical microscope image of the bundled magnetic photonic crystal during the purely mechanical thrombolysis process in this embodiment. It can be observed that the magnetic photonic crystal nanobundle can open a channel for blood flow through the thrombus within 200s.

[0082] The above embodiments merely illustrate implementation methods of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A beam-shaped magnetic photonic crystal, characterized in that, The bundled magnetic photonic crystal is composed of multiple one-dimensional magnetic photonic nanochains tightly packed together and fixedly connected by silicon dioxide. Each one-dimensional magnetic photonic nanochain is assembled into a chain by multiple magnetic nanoparticles. The magnetic nanoparticles in the bundled magnetic photonic crystal are arranged in a one-dimensional photonic crystal structure along the axial direction of the bundled magnetic photonic crystal and in a two-dimensional photonic crystal structure along the radial direction of the bundled magnetic photonic crystal.

2. The bundled magnetic photonic crystal according to claim 1, characterized in that, The magnetic nanoparticles contain at least one magnetic element selected from iron, cobalt, and nickel, and have a particle size of 80-200 nm.

3. The bundled magnetic photonic crystal according to claim 1, characterized in that, The bundled magnetic photonic crystal exhibits the structural color of a photonic crystal along both the axial and radial directions.

4. A method for preparing a bundled magnetic photonic crystal according to any one of claims 1-3, characterized in that, The steps include: (1) dispersing superparamagnetic colloidal nanoparticles in a polar solvent, adding a silicon source and a catalyst, mixing them evenly, and then using the mixture as a prepolymer solution; (2) Apply a magnetic field above the prepolymer liquid and let it stand to react. After the reaction is completed, clean and remove impurities to obtain the bundled magnetic photonic crystal.

5. The method for preparing a bundled magnetic photonic crystal according to claim 4, characterized in that, In step (1), the superparamagnetic colloidal nanoparticles contain at least one magnetic element selected from iron, cobalt, and nickel, have a particle size of 80-200 nm, and have a concentration of 0.4-2.0 mg / mL in the prepolymer solution.

6. The method for preparing a bundled magnetic photonic crystal according to claim 4, characterized in that, In step (1), the polar solvent is a mixture of ethanol and water, with a volume ratio of ethanol to water of 8:2-4:

6.

7. The method for preparing a bundled magnetic photonic crystal according to claim 4, characterized in that, In step (1), the silicon source includes at least one of tetraethyl orthosilicate, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, silicon tetrachloride, and methyl orthosilicate, and its concentration in the prepolymer solution is 0.08 - 0.20 mmol / mL.

8. The method for preparing a bundled magnetic photonic crystal according to claim 4, characterized in that, In step (1), the catalyst includes at least one of ammonia, sodium hydroxide, potassium hydroxide, organic amine, polyacrylic acid, hydrochloric acid, and acetic acid, and the molar ratio of the catalyst to the silicon source is 2:5-2:

1.

9. The method for preparing a bundled magnetic photonic crystal according to claim 4, characterized in that, In step (2), the strength of the magnetic field is 300-600 Gs; the reaction time is 7-20 min; and the reaction temperature is 5-30℃.

10. The application of a bundled magnetic photonic crystal according to any one of claims 1-3 or a bundled magnetic photonic crystal prepared by the preparation method according to any one of claims 4-9, characterized in that: The aforementioned bundled magnetic photonic crystals can be applied to micro- and nano-devices for color displays, drug carriers, anti-counterfeiting, or magnetic drive motors.

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