Total internal reflection structural color microspheres with magnetic response and preparation method and application thereof

Abstract

The invention provides a total internal reflection structural color microsphere with magnetic response as well as a preparation method and application of the total internal reflection structural color microsphere. According to the total internal reflection structural color microsphere with the magnetic response, when an external magnetic field is introduced and the direction of the magnetic field is perpendicular to the plane of the microsphere, the concave interface of the magnetic structural color microsphere directly faces vertically-incident incident light, and the incident light is subjected to total internal reflection for multiple times at the concave interface and generates a structural color through the interference effect; when a deflection magnetic field is applied to the microspheres, all the microspheres are arranged in an orientation mode in the direction of the magnetic field, at the moment, concave interfaces of the microspheres deflect, the condition that the structural color is generated through the synergistic effect of total internal reflection and interference is not met, and therefore the structural color cannot be generated, and the magnetic response of the total internal reflection structural color microspheres is achieved; the preparation method is simple, easy to operate and low in technical requirement, the structural color microspheres with the micro-nano size, uniform and controllable size can be conveniently prepared, the needed raw materials are cheap and easy to obtain, and the preparation method is suitable for large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of structural color materials, and particularly to a total internal reflection structural color microsphere with magnetic response, a preparation method thereof, and an application thereof. Background Art

[0002] Structural color is generated by the interaction of light with nano / micro structures (such as diffraction, reflection, and interference). In nature, after millions of years of evolution, structural color widely exists in plants and animals and plays an important role in their predation, courtship, and camouflage. Different from chemical color that selectively absorbs light, structural color has attracted much attention due to its unique optical properties, environmental friendliness, high saturation, and fade resistance. As a new type of structural color mechanism, total internal reflection structural color mainly originates from the interaction of light with micron-scale concave optical structures and is generated through the synergistic effect of total internal reflection and interference.

[0003] With the in-depth understanding of micro-nano structured artificial materials by people, significant progress has been made in the preparation and regulation technologies of total internal reflection structural color. However, a single total internal reflection structural color material is not sufficient to meet the requirements of practical applications.

[0004] Based on the deficiencies of the current single total internal reflection structural color material, it is necessary to improve it. Summary of the Invention

[0005] In view of the above deficiencies or improvement requirements of the prior art, the purpose of the present invention is to provide a total internal reflection structural color microsphere with magnetic response, its preparation method and application. The present invention consists of two monomers with different refractive indices, two different surfactants, and magnetically modified Fe3O4 particles. Due to the surface modification of the magnetically modified Fe3O4 particles, they can be stably and uniformly dispersed in the total internal reflection structural color microspheres; when an external magnetic field is introduced, when the magnetic field direction is perpendicular to the microsphere plane, the concave interface of the magnetic structural color microsphere faces the incident light incident perpendicularly, and multiple total internal reflections occur at the concave interface and structural color is generated through the interference effect. When a deflecting magnetic field is applied to the microspheres, the microspheres will all be arranged in an orientation along the magnetic field direction. At this time, the concave interface of the microspheres deflects, and the conditions for generating structural color through the synergistic effect of total internal reflection and interference are not met, so structural color cannot be generated, thereby realizing the magnetic response of the total internal reflection structural color microspheres. The magnetically responsive total internal reflection structural color microspheres obtained by the present invention can realize the display and disappearance of structural color by adjusting the deflection direction of the external magnetic field; at the macroscopic level, the change of color display and disappearance can also be directly observed by the naked eye, which makes it have a wide application prospect in the field of anti-counterfeiting. In addition, the preparation process of the present invention is simple, the raw material cost is low, and batch preparation can be realized. Compared with other structural color materials, the structural color microspheres of the present invention also have the advantages of anti-fading, environmental protection, high saturation, no need for complex periodic structures, and strong magnetic response ability, etc.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a preparation method of a total internal reflection structural color microsphere with magnetic response, including the following steps:

[0008] Add the first surfactant into water to obtain the first surfactant solution;

[0009] Add the second surfactant into water to obtain the second surfactant solution;

[0010] Mix the first surfactant solution and the second surfactant solution to obtain an aqueous phase mixture;

[0011] Add the magnetically modified Fe3O4 particles into isopropanol, then add the fluorinated monomer, and ultrasonically modify the magnetically modified Fe3O4 particles, and separate to obtain the modified magnetically modified Fe3O4 particles;

[0012] Add the hydrocarbon, the fluorocarbon, and the modified magnetically modified Fe3O4 particles into the co-solvent to obtain an oil phase mixture;

[0013] The aqueous phase mixture and the oil phase mixture are respectively introduced into a microfluidic chip to prepare all-internal reflection structural color microspheres with magnetic response;

[0014] Among them, the hydrocarbon and the fluorocarbon are immiscible, the density of the hydrocarbon is less than that of the fluorocarbon, and the refractive index of the hydrocarbon is greater than that of the fluorocarbon;

[0015] The first surfactant is used to reduce the interfacial tension between the fluorocarbon and water;

[0016] The second surfactant is used to reduce the interfacial tension between the hydrocarbon and water.

[0017] Preferably, the microfluidic chip includes:

[0018] An outer pipe, one end of which is communicated with an aqueous phase mixture feed pipe;

[0019] A first inner pipe, one end of which is sleeved inside the outer pipe and the other end extends outside the outer pipe;

[0020] A second inner pipe, one end of which is sleeved inside the outer pipe and the other end extends outside the outer pipe;

[0021] The first inner pipe and the second inner pipe are distributed on both sides of the outer pipe, and the ends of the first inner pipe and the second inner pipe located inside the outer pipe form a gap;

[0022] The aqueous phase mixture is injected into the outer pipe through the aqueous phase mixture feed pipe, the oil phase mixture is injected into the first inner pipe, the oil phase mixture is sheared by the aqueous phase mixture at the gap and flows out through the second inner pipe to form emulsion microspheres with uniform size; after the co-solvent in the emulsion microspheres volatilizes and phase separation occurs, all-internal reflection structural color microspheres with magnetic response are obtained.

[0023] Preferably, the first surfactant includes at least one of FC-4430, FC301, Capstone FS-30, Capstone62MA, ZY-FC327, ZY-823, ZONLYFS300, TF282, TF328;

[0024] And / or, the second surfactant includes at least one of SDS, PVA, F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, TWEEN 80, CTAB, CTAC.

[0025] Preferably, the hydrocarbon includes at least one of octadecyl methacrylate, ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate, glycidyl methacrylate, tert-butyl bromoacetate, n-butyl acrylate, dodecyl acrylate, and trimethylolpropane triacrylate;

[0026] and / or, the fluorocarbon includes at least one of 1H,1H,2H,2H-heptadecafluorodecyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, hexafluorobutyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, trifluoroethyl methacrylate, perfluoroalkyl ethyl acrylate, (N-methyl perfluorohexylsulfonylamino)ethyl acrylate, perfluorooctyl ethyl acrylate, perfluorohexyl ethyl methacrylate, perfluoroalkyl acrylate, dodecafluorooctyl acrylate, perfluoroalkyl ethyl methacrylate, and perfluoropolyether methacrylate;

[0027] and / or, the co-solvent includes at least one of chloroform, dichloromethane, n-hexane, and toluene;

[0028] and / or, the fluorinated monomer includes at least one of (1H,1H,2H,2H-heptadecafluorodecyl)phosphonic acid, perfluorohexylphosphonic acid, perfluorooctylphosphonic acid, 1H,1H,2H,2H-perfluorooctane phosphonic acid, bis(perfluorooctyl)phosphonic acid, (perfluoroethyl)phosphonic acid, and perfluorododecylphosphonic acid.

[0029] Preferably, the concentration of the first surfactant solution is 1 - 30 mg / mL;

[0030] the concentration of the second surfactant solution is 1 - 30 mg / mL;

[0031] The mass ratio of the first surfactant to the second surfactant is (1 - 2):3.

[0032] Preferably, magnetic Fe3O4 particles are added to isopropanol, and then a fluorinated monomer is added to obtain a mixture, where the concentration of magnetic Fe3O4 particles in the mixture is 1 - 10 mg / mL and the concentration of the fluorinated monomer is 0.01 - 0.5 mmol / mL.

[0033] Preferably, in the step of adding the hydrocarbon, the fluorocarbon, and the modified magnetic Fe3O4 particles to the co-solvent, the concentration of the modified magnetic Fe3O4 particles is 0.3 - 3 mg / mL;

[0034] The volume ratio of the hydrocarbon to the fluorocarbon is (1:9) - (7:3).

[0035] Preferably, the aqueous mixture is injected into the outer pipe through the aqueous mixture feed pipe at a rate of 50 - 500 μL / min;

[0036] The oil phase mixture is injected into the first inner pipe at a rate of 5 - 30 μL / min.

[0037] In a second aspect, the present invention also provides a total internal reflection structural color microsphere with magnetic response, which is prepared by the described preparation method.

[0038] In a third aspect, the present invention also provides an application of the total internal reflection structural color microsphere with magnetic response prepared by the described preparation method or the total internal reflection structural color microsphere with magnetic response in intelligent display, anti-counterfeiting materials, biological detection, information encryption.

[0039] The total internal reflection structural color microsphere with magnetic response of the present invention, its preparation method and application have the following beneficial effects compared with the prior art:

[0040] 1. The total internal reflection structural color microsphere with magnetic response prepared by the present invention is composed of two monomers with different refractive indices (i.e., hydrocarbon, fluorocarbon), two different surfactants (i.e., the first surfactant, the second surfactant), and surface-modified magnetic Fe3O4 particles. Due to the surface modification of the magnetic Fe3O4 particles, they can be stably and uniformly dispersed in the total internal reflection structural color microsphere; when an external magnetic field is introduced, when the magnetic field direction is perpendicular to the microsphere plane, the concave interface of the magnetic structural color microsphere faces the incident light incident perpendicularly, and multiple total internal reflections occur at the concave interface and structural color is generated through interference; when a deflecting magnetic field is applied to the microsphere, the microspheres will all be arranged in an orientation along the magnetic field direction. At this time, the concave interface of the microspheres deflects, and the conditions for generating structural color through the synergistic action of total internal reflection and interference are not met, so structural color cannot be generated, thus realizing the magnetic response of the total internal reflection structural color microsphere; the preparation method of the total internal reflection structural color microsphere with magnetic response of the present invention is simple, the operation is simple, the technical requirements are low, and it can conveniently prepare micro-nano-sized, uniformly sized, and controllable structural color microspheres. The raw materials required are cheap and easy to obtain, and it is suitable for large-scale production;

[0041] 2. The present invention can adjust the color of the microsphere structural color by adjusting the mass ratio of the surfactants and the volume ratio of the hydrocarbon to the fluorocarbon, and is applicable to fields such as anti-counterfeiting; the total internal reflection structural color microsphere with magnetic response of the present invention can realize the display and disappearance of the structural color by adjusting the deflection direction of the external magnetic field; at the same time, at the macroscopic level, the change of color display and disappearance can also be directly observed by the naked eye, which makes it have a wide application prospect in the anti-counterfeiting field. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Figure 1 Schematic diagram of the structure of the microfluidic chip of the present invention;

[0044] Figure 2 Optical microscope images of the Janus microspheres with total internal reflection structural color prepared in Example 1 and the optical microscope images under a deflecting magnetic field;

[0045] Figure 3 Optical microscope images of the Janus microspheres with total internal reflection structural color prepared in Example 2 and the optical microscope images under a deflecting magnetic field. Detailed implementation manners

[0046] The following will describe clearly and completely the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper" is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0048] The description order of the following embodiments does not limit the preferred order of the embodiments. Additionally, in the description of this application, the term "comprising" means "including but not limited to". The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0049] An embodiment of this application provides a method for preparing a total internal reflection structural color microsphere with magnetic response, including the following steps:

[0050] S1. Add a first surfactant to water to obtain a first surfactant solution;

[0051] S2. Add a second surfactant to water to obtain a second surfactant solution;

[0052] S3. Mix the first surfactant solution and the second surfactant solution to obtain an aqueous phase mixture;

[0053] S4. Add magnetic Fe3O4 particles to isopropanol, then add a fluorinated monomer, and ultrasonically modify the magnetic Fe3O4 particles, and separate to obtain modified magnetic Fe3O4 particles;

[0054] S5. Add a hydrocarbon, a fluorocarbon, and the modified magnetic Fe3O4 particles to a co-solvent to obtain an oil phase mixture;

[0055] S6. Pass the aqueous phase mixture and the oil phase mixture into a microfluidic chip respectively to prepare a total internal reflection structural color microsphere with magnetic response;

[0056] Wherein, the hydrocarbon and the fluorocarbon are immiscible with each other, the density of the hydrocarbon is less than that of the fluorocarbon, and the refractive index of the hydrocarbon is greater than that of the fluorocarbon;

[0057] The first surfactant is used to reduce the interfacial tension between the fluorocarbon and water;

[0058] The second surfactant is used to reduce the interfacial tension between the hydrocarbon and water.

[0059] The present invention consists of two monomers with different refractive indices (i.e., hydrocarbon and fluorocarbon), two different surfactants (i.e., the first surfactant and the second surfactant), and magnetically modified Fe3O4 particles. Due to the surface modification of the magnetically Fe3O4 particles, they can be stably and uniformly dispersed in the total internal reflection structural color microspheres. When an external magnetic field is introduced, when the magnetic field direction is perpendicular to the microsphere plane, the concave interface of the magnetic structural color microsphere faces the incident light incident perpendicularly. At the concave interface, the incident light undergoes multiple total internal reflections and generates structural color through interference. When a deflecting magnetic field is applied to the microsphere, the microspheres will all be arranged along the magnetic field direction. At this time, the concave interface of the microsphere deflects, and the condition for generating structural color through the synergistic effect of total internal reflection and interference is not satisfied, so structural color cannot be generated, thereby realizing the magnetic response of the total internal reflection structural color microspheres. The magnetically responsive total internal reflection structural color microspheres obtained by the present invention can realize the display and disappearance of structural color by adjusting the deflecting direction of the external magnetic field. At the macroscopic level, the change in color display and disappearance can also be directly observed by the naked eye, which makes it have a wide application prospect in the anti-counterfeiting field. In addition, the preparation process of the present invention is simple, the raw material cost is low, and batch preparation can be realized. Compared with other structural color materials, the structural color microspheres of the present invention also have advantages such as anti-fading, environmental protection, high saturation, no need for complex periodic structures, and strong magnetic response ability.

[0060] The magnetically responsive total internal reflection structural color microspheres prepared by the present invention can provide real-time feedback to external stimuli, converting difficult-to-observe external stimuli into optically visible signals. Compared with common external field stimuli such as temperature or pH, the externally applied magnetic field has the advantages of non-contact, easy control, and fast response speed. It does not need to change the original physical or chemical environment of the system and is a non-invasive stimulation method. Secondly, by surface-modifying the magnetically Fe3O4 particles, the prepared total internal reflection microspheres have good stability and strong magnetic response ability. It has great potential in the fields of intelligent display, anti-counterfeiting, biological detection, information encryption, etc.

[0061] In some embodiments, as Figure 1 shown, the microfluidic chip includes:

[0062] An outer pipe 1, one end of which is connected with an aqueous phase mixture feed pipe 2;

[0063] A first inner pipe 4, one end of which is sleeved inside the outer pipe 1 and the other end extends outside the outer pipe 1;

[0064] A second inner pipe 5, one end of which is sleeved inside the outer pipe 1 and the other end extends outside the outer pipe 1;

[0065] The first inner pipe 4 and the second inner pipe 5 are distributed on both sides of the outer pipe, and the ends of the first inner pipe 4 and the second inner pipe 5 located inside the outer pipe form a gap 11;

[0066] Inject the aqueous mixture into the outer pipe 1 through the aqueous mixture feed pipe 2, inject the oil-phase mixture into the first inner pipe 4, and the oil-phase mixture is sheared by the aqueous mixture at the gap 11 and flows out through the second inner pipe 5 to form emulsion microspheres with uniform size; wait for the co-solvent in the emulsion microspheres to volatilize, and phase separation occurs to obtain magnetically responsive total internal reflection structural color microspheres.

[0067] Specifically, the microfluidic chip of the present invention includes an outer pipe 1, a first inner pipe 4, and a second inner pipe 5; both ends of the outer pipe 1 are closed. Among them, one end of the outer pipe 1 is connected with an aqueous mixture feed pipe 2, and the other end is connected with an exhaust pipe 3; the first inner pipe 4 and the second inner pipe 5 are distributed on both sides of the outer pipe 1, and the ends of the first inner pipe 4 and the second inner pipe 5 close to each other both extend into the outer pipe 1, while the ends of the first inner pipe 4 and the second inner pipe 5 far from each other both extend out of the outer pipe 1, and a gap 11 is formed between the ends of the first inner pipe 4 and the second inner pipe 5 close to each other; inject the aqueous mixture into the outer pipe 1 through the aqueous mixture feed pipe 2, inject the oil-phase mixture into the first inner pipe 4, and the oil-phase mixture is sheared by the aqueous mixture to form uniform emulsion microspheres and flow out through the second inner pipe 5; volatilize the emulsion microspheres at (20 - 25 °C), and after the co-solvent completely volatilizes, the immiscible hydrocarbon and fluorocarbon undergo phase separation to form microspheres with a Janus structure (the Janus structure is a material or particle with asymmetry or anisotropy characteristics. The Janus structure usually consists of two or more different parts, each part having different physical, chemical, or functional characteristics). At this time, the prepared microspheres have total internal reflection structural color, and magnetically responsive total internal reflection structural color microspheres are obtained.

[0068] In some embodiments, the first surfactant can preferentially reduce the interfacial tension between the fluorocarbon and water. The first surfactant includes at least one of FC-4430, FC301, Capstone FS-30, Capstone 62MA, ZY-FC327, ZY-823, ZONLYFS300, TF282, TF328.

[0069] Specifically, FC-4430 is a non-ionic polymeric fluorosurfactant, manufactured by 3M in the United States, with the model number Fluorad FC-44304; FC301 is a fluorosurfactant, manufactured by Shanghai Futian Chemical Technology Co., Ltd.; Capstone FS-30 is the Chemours fluorocarbon surfactant Capstone FS-30 by DuPont in the United States; Capstone 62MA belongs to the Capstone series of surfactants, manufactured by DuPont / Chemours, with the model number DuPont TM 62-MA; ZY-FC327 is a fluorosurfactant, manufactured by Shanghai Ziyi Chemical Co., Ltd., with the model number FC327; ZY-823 is the ZY-823 fluorocarbon surfactant of Shanghai Ziyi Chemical Co., Ltd.; ZONLYFS300 is Zonyl FS300, manufactured by DuPont in the United States, with the model number Zonyl FS-300; TF282 is the fluorocarbon surfactant TF282 of Shanghai Futian Chemical Technology Co., Ltd.; TF328 is the fluorocarbon surfactant TF328 of Shanghai Futian Chemical Technology Co., Ltd.

[0070] In some embodiments, the second surfactant includes at least one of SDS, PVA, F-108, F-127, TWEEN 20, TWEEN40, TWEEN 60, TWEEN 80, CTAB, CTAC.

[0071] Specifically, SDS is sodium dodecyl sulfate, purchased from Sigma-Aldrich; PVA is polyvinyl alcohol; F-108 (Pluronic F-108) is F 108 of BASF, purchased from Shanghai Macklin Biochemical Co., Ltd.; F-127 (Pluronic F-127) is Synperonic PE-F127 of Croda in the UK, purchased from Shanghai Macklin Biochemical Co., Ltd.; TWEEN 20 (Tween 20) is Tween 20 of Croda in the UK, purchased from Shanghai Macklin Biochemical Co., Ltd.; TWEEN 40 (Tween 40) is Tween 40, purchased from Shanghai Macklin Biochemical Co., Ltd.; TWEEN 60 (Tween 60) is Tween 60, purchased from Shanghai Macklin Biochemical Co., Ltd.; TWEEN 80 (Tween 80) is Tween 80, purchased from Shanghai Macklin Biochemical Co., Ltd.; CTAB is cetyltrimethylammonium bromide, purchased from Shanghai Macklin Biochemical Co., Ltd.; CTAC is cetyltrimethylammonium chloride, purchased from Shanghai Macklin Biochemical Co., Ltd.

[0072] In some embodiments, the hydrocarbon includes at least one of octadecyl methacrylate (molecular formula: C 22 H 42 O2), ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate (molecular formula: C 10 H 14 O4), glycidyl methacrylate (molecular formula: C7H 10 O3), tert-butyl bromoacetate (molecular formula: C6H 11 BrO2), n-butyl acrylate (molecular formula: C7H 12 O2), dodecyl acrylate (molecular formula: C 15 H 28 O2), trimethylolpropane triacrylate (molecular formula: C 15 H 17 O9).

[0073] In some embodiments, the fluorocarbon includes at least one of 1H,1H,2H,2H-heptadecafluorodecyl acrylate (CAS No.: 27905-45-9), 1,1,1,3,3,3-hexafluoroisopropyl methacrylate (CAS No.: 3063-94-3, molecular formula: C7H6F6O2), 2,2,2-trifluoroethyl methacrylate (CAS No.: 352-87-4, molecular formula: C6H7F3O2), hexafluorobutyl methacrylate (CAS No.: 36405-47-7, molecular formula: C8H8F6O2), 2,2,3,4,4,4-hexafluorobutyl acrylate (CAS No.: 54052-90-3, molecular formula: C7H6F6O2), trifluoroethyl methacrylate (CAS No.: 352-87-4, molecular formula: C6H7F3O2), perfluoroalkyl ethyl acrylate (CAS No.: 65605-70-1), (N-methyl perfluorohexylsulfonamido) ethyl acrylate (CAS No.: 67584-57-0), perfluorooctyl ethyl acrylate (CAS No.: 27905-45-9), perfluorohexyl ethyl methacrylate (CAS No.: 2144-53-8), perfluoroalkyl acrylate, dodecafluoroheptyl acrylate (CAS No.: 20109-57-3), perfluoroalkyl ethyl methacrylate (CAS No.: 65530-66-7), and perfluoropolyether methacrylate.

[0074] In some embodiments, the co-solvent includes at least one of chloroform, dichloromethane, n-hexane, and toluene.

[0075] In some embodiments, the fluorinated monomer includes at least one of (1H,1H,2H,2H-heptadecafluorodecyl)phosphonic acid (CAS No.: 80220-63-9), perfluorohexylphosphonic acid (CAS No.: 40143-76-8), perfluorooctylphosphonic acid (CAS No.: 40143-78-0), 1H,1H,2H,2H-perfluorooctane phosphonic acid (CAS No.: 252237-40-4), bis(perfluorooctyl)phosphonic acid, (perfluoroethyl)phosphonic acid, perfluorododecylphosphonic acid (CAS No.: 63225-55-8).

[0076] In some embodiments, the concentration of the first surfactant solution is 1 - 30 mg / mL;

[0077] In some embodiments, the concentration of the second surfactant solution is 1 - 30 mg / mL;

[0078] In some embodiments, the mass ratio of the first surfactant to the second surfactant is (1 - 2):3.

[0079] In some embodiments, the volume ratio of the hydrocarbon to the fluorocarbon is (1 - 9):(7 - 3).

[0080] In some embodiments, magnetic Fe3O4 particles are added to isopropanol, and then a fluorinated monomer is added to obtain a mixture. The concentration of magnetic Fe3O4 particles in the mixture is 1 - 10 mg / mL, and the concentration of the fluorinated monomer is 0.01 - 0.5 mmol / mL.

[0081] In some embodiments, magnetic Fe3O4 particles are added to isopropanol, and then a fluorinated monomer is added to obtain a mixture. The magnetic Fe3O4 particles are surface-modified by ultrasonic treatment at room temperature for 30 min. The magnetic Fe3O4 particles are separated by centrifugation. After removing the supernatant, the magnetic Fe3O4 particles are redispersed in isopropanol and centrifuged and washed three times to remove the unreacted fluorinated monomer. After drying, the modified magnetic Fe3O4 particles are obtained.

[0082] In some embodiments, in the step of adding the hydrocarbon, the fluorocarbon, and the modified magnetic Fe3O4 particles to the co-solvent, the concentration of the modified magnetic Fe3O4 particles is 0.3 - 3 mg / mL; the volume ratio of the hydrocarbon to the fluorocarbon is (1:9) - (7:3); specifically, the amount of the co-solvent added is not limited and can be selected according to the actual situation. For example, the added amount is 10 times the sum of the volumes of the hydrocarbon and the fluorocarbon.

[0083] In some embodiments, the aqueous phase mixture is injected into the outer pipe through the aqueous phase mixture feed pipe at a rate of 50 - 500 μL / min;

[0084] Inject the oil-phase mixture into the first inner pipe at a rate of 5 - 30 μL / min.

[0085] Specifically, when the mass ratio of the first surfactant to the second surfactant in the system satisfies (1 - 2):3, and the volume ratio of the hydrocarbon to the fluorocarbon is (1:9) - (3:2), the morphology of the microspheres is Janus microspheres with structural color. At the same time, when the content of the surface-modified Fe3O4 nanoparticles in the system is 0.3 - 3 mg / mL, under the condition of an external magnetic field, the display and disappearance of the structural color can be achieved through the deflection of the magnetic field.

[0086] In some embodiments, the particle size of the magnetic Fe3O4 particles is 10 - 40 nm, and the inner diameter of the outer pipe 1 is 1 - 1.1 mm; the inner diameter of the larger-diameter end of the first inner pipe 4 (i.e., the end close to the aqueous-phase mixture feed pipe 2) is 700 - 900 μm, and the inner diameter of the smaller-diameter end (i.e., the end close to the spacer 11) is 50 - 70 μm; the inner diameter of the smaller-diameter end of the second inner pipe 5 (i.e., the end close to the spacer 11) is 100 - 140 μm, and the inner diameter of the larger-diameter end (i.e., the end close to the exhaust pipe 3) is 800 - 950 μm.

[0087] The microspheres in the present invention are composed of immiscible hydrocarbons and fluorocarbons. When the morphology of the microspheres is Janus microspheres, based on the characteristics that the density of hydrocarbons is less than that of fluorocarbons but the refractive index is greater than that of fluorocarbons, the microspheres can generate structural color synergistically based on the total internal reflection and interference mechanisms. Moreover, after adding the modified Fe3O4 nanoparticles, the deflection direction of the microspheres can be further changed by simply adjusting the deflection direction of the external magnetic field, so that the structural color of the microspheres can be displayed and disappeared.

[0088] Specifically, a co-solvent (i.e., an oil-phase mixture) dissolved with hydrocarbons, fluorocarbons, and modified magnetic Fe3O4 particles is used as the dispersed phase, and two mutually miscible surfactants (i.e., an aqueous-phase mixture) are used as the continuous phase. The microfluidic chip is connected through a silica gel hose. The two mutually miscible surfactants serve as the outer phase, and the flow rate of the outer phase is 50 - 500 μL / min (i.e., the flow rate of the aqueous-phase mixture is 50 - 500 μL / min); the co-solvent dissolved with hydrocarbons and fluorocarbons is the inner phase, and the flow rate of the inner phase is 5 - 30 μL / min (i.e., the flow rate of the oil-phase mixture is 5 - 30 μL / min); the dispersed phase is subjected to the shearing action of the continuous-phase solution to form emulsion microspheres with uniform and stable sizes; the diameter of the emulsion microspheres is 10 - 200 μm; emulsion microspheres with different sizes can be obtained by adjusting the flow rates of the dispersed phase and the continuous phase; the obtained emulsion microspheres are left to volatilize at room temperature (20 - 25 °C) for 24 h. After the co-solvent is completely volatilized, the microspheres form a Janus structure. At this time, the microspheres have a total internal reflection structural color, and the diameter of the microspheres is 10 - 200 μm; the microspheres with the total internal reflection structural color are placed under an external magnetic field. When the magnetic field direction is perpendicular to the plane of the microspheres, the concave interface of the magnetic structural color microspheres faces the incident light incident perpendicularly. At the concave interface, the incident light undergoes multiple total internal reflections and generates a structural color through interference. When a deflecting magnetic field is applied to the microspheres, the microspheres will all be oriented and arranged along the magnetic field direction. At this time, the concave interface of the microspheres deflects, and the conditions for generating a structural color through the synergistic effect of total internal reflection and interference are not met. Therefore, no structural color can be generated, thus realizing the magnetic response of the total internal reflection structural color microspheres.

[0089] Based on the same inventive concept, the present invention also provides a total internal reflection structural color microsphere with magnetic response, which is prepared by the above-mentioned preparation method.

[0090] Based on the same inventive concept, the present invention also provides an application of the total internal reflection structural color microsphere with magnetic response prepared by the above-mentioned preparation method or the above-mentioned total internal reflection structural color microsphere with magnetic response in intelligent display, anti-counterfeiting materials, biological detection, and information encryption.

[0091] The Janus microspheres with total internal reflection structural color prepared by the present invention are placed under an external magnetic field. When the content of surface-modified Fe3O4 nanoparticles in the system satisfies 0.3 - 3 mg / mL and the magnetic field direction is perpendicular to the microsphere plane, the concave interface of the magnetic structural color microspheres faces the perpendicularly incident light. At the concave interface, the incident light undergoes multiple total internal reflections and generates structural color through interference. When a deflecting magnetic field is applied to the microspheres, the microspheres will all be arranged in an orientation along the magnetic field direction. At this time, the concave interface of the microspheres deflects, and the condition for generating structural color through the synergistic action of total internal reflection and interference is not satisfied. Therefore, structural color cannot be generated, thus realizing the magnetic response of the total internal reflection structural color microspheres. Through the above technical solution conceived by the present invention, compared with the prior art, two different surfactants are used, and by the cooperation of the first surfactant, the second surfactant, hydrocarbons, fluorocarbons, and surface-modified Fe3O4 nanoparticles, Janus microspheres with structural color are obtained. Subsequently, deflection is caused by applying an external magnetic field, so that the structural color of the Janus microspheres can be displayed and disappeared.

[0092] The following further illustrates the total internal reflection structural color microspheres with magnetic response of the present application, their preparation methods and applications with specific examples. This part further illustrates the content of the present invention with specific examples, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means adopted in the examples are conventional means well-known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0093] In the following examples, the inner diameter of the outer pipe 1 is 1.1 mm; the inner diameter of the larger end of the first inner pipe 4 is 800 μm, and the inner diameter of the smaller end is 60 μm; the inner diameter of the smaller end of the second inner pipe 5 is 120 μm, and the inner diameter of the larger end is 900 μm.

[0094] Example 1

[0095] The embodiment of the present application provides a preparation method for total internal reflection structural color microspheres with magnetic response, including the following steps:

[0096] S1. Add the first surfactant Capstone FS-30 to water to obtain a first surfactant solution; the concentration of the first surfactant solution is 10 mg / mL;

[0097] S2. Add the second surfactant SDS (sodium dodecyl sulfate) to water to obtain a second surfactant solution; the concentration of the second surfactant solution is 10 mg / mL;

[0098] S3. Mix the first surfactant solution and the second surfactant solution to obtain an aqueous phase mixture. The volume ratio of the first surfactant solution to the second surfactant solution is 1:3.

[0099] S4. Add magnetic Fe3O4 particles (average particle size 25 nm) to isopropanol, and then add a fluorinated monomer, (1H,1H,2H,2H-heptadecafluorodecyl)phosphonic acid, to obtain a mixture. Ultrasonically modify the magnetic Fe3O4 particles at room temperature (25 °C) for 30 min, and then centrifuge at 10000 rpm for 15 min to separate the Fe3O4 nanoparticles. After removing the supernatant, disperse them in 3 mL of isopropanol and repeat three times to remove the unreacted fluorinated monomer ((1H,1H,2H,2H-heptadecafluorodecyl)phosphonic acid), and dry in a vacuum oven for 24 h to obtain modified magnetic Fe3O4 particles. Among them, the concentration of magnetic Fe3O4 particles in the mixture is 4 mg / mL, and the concentration of the fluorinated monomer (1H,1H,2H,2H-heptadecafluorodecyl)phosphonic acid is 0.05 mmol / mL.

[0100] S5. Add ethoxylated trimethylolpropane triacrylate (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No.: 28961-43-5), 1H,1H,2H,2H-heptadecafluorodecyl acrylate, and the modified magnetic Fe3O4 particles in S4 to chloroform to obtain an oil phase mixture. The concentration of the modified magnetic Fe3O4 particles in the oil phase mixture is 1 mg / mL, and the volume ratio of ethoxylated trimethylolpropane triacrylate to 1H,1H,2H,2H-heptadecafluorodecyl acrylate is 1:1. The volume of chloroform is not limited. In this example, for the convenience of the experiment, the volume of chloroform is 10 times the sum of the volumes of ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H-heptadecafluorodecyl acrylate.

[0101] S6. Provide Figure 1 the microfluidic chip shown;

[0102] Inject the aqueous phase mixture in S3 into the outer pipe at a rate of 180 μL / min through the aqueous phase mixture feed pipe.

[0103] Inject the oil phase mixture in S5 into the first inner pipe at a rate of 15 μL / min. The aqueous phase mixture and the oil phase mixture are mixed at the interval and flow out through the second inner pipe to form emulsion microspheres with a diameter of 50 μm.

[0104] The prepared emulsion microspheres were placed at room temperature (25 °C) for volatilization. After the co-solvent chloroform was completely volatilized, the microspheres underwent phase separation to form microspheres with a Janus structure. Due to the action of the surfactant and the two-phase volume ratio, the microspheres with a Janus structure had a total internal reflection structural color at this time, that is, magnetic-responsive total internal reflection structural color microspheres were obtained.

[0105] The microspheres with a total internal reflection structural color prepared in Example 1 were placed under a magnetic field. The orientation of the microspheres was controlled by adjusting the direction of the applied magnetic field, and the morphology and color changes of the microspheres were observed under a reflection-mode optical microscope.

[0106] As Figure 2 shown, Figure 2 in (a) is an optical microscope image of the Janus microspheres with a total internal reflection structural color prepared in step S6 of Example 1, and its color is purple; Figure 2 in (b) is an optical microscope image of the Janus microspheres with a total internal reflection structural color under a deflected magnetic field. It can be seen that by controlling the direction of the applied magnetic field, the Janus microspheres deflect, and their structural color gradually disappears from purple.

[0107] Example 2

[0108] The embodiment of the present application provides a preparation method of magnetic-responsive total internal reflection structural color microspheres, including the following steps:

[0109] S1. Add the first surfactant Capstone FS-30 to water to obtain a first surfactant solution; the concentration of the first surfactant solution is 5 mg / mL;

[0110] S2. Add the second surfactant SDS (sodium dodecyl sulfate) to water to obtain a second surfactant solution; the concentration of the second surfactant solution is 15 mg / mL;

[0111] S3. Mix the first surfactant solution and the second surfactant solution to obtain an aqueous phase mixture; the volume ratio of the first surfactant solution to the second surfactant solution is 9:7;

[0112] S4. Add magnetic Fe3O4 particles (average particle size 25 nm) to isopropanol, then add the fluorinated monomer perfluorooctylphosphonic acid to obtain a mixture. Ultrasonically treat the magnetic Fe3O4 particles for 30 min at room temperature (25 °C) for surface modification, then centrifuge at 10000 rpm for 15 min to separate the Fe3O4 nanoparticles. After removing the supernatant, disperse them in 3 mL of isopropanol and repeat three times to remove the unreacted fluorinated monomer (perfluorooctylphosphonic acid), and dry in a vacuum oven for 24 h to obtain modified magnetic Fe3O4 particles; wherein, the concentration of magnetic Fe3O4 particles in the mixture is 5 mg / mL, and the fluorinated monomer perfluorooctylphosphonic acid is 0.04 mmol / mL;

[0113] S5. Add ethoxylated trimethylolpropane triacrylate, 1H,1H,2H,2H - heptadecafluorodecyl acrylate, and the modified magnetic Fe3O4 particles in S4 to chloroform to obtain an oil - phase mixture; the concentration of the modified magnetic Fe3O4 particles in the oil - phase mixture is 1 mg / mL, and the volume ratio of ethoxylated trimethylolpropane triacrylate to 1H,1H,2H,2H - heptadecafluorodecyl acrylate is 3:7; the volume of chloroform is not limited. In this example, for the convenience of the experiment, the volume of chloroform is 10 times the sum of the volumes of ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H - heptadecafluorodecyl acrylate;

[0114] S6. Provide Figure 1 the microfluidic chip shown;

[0115] Inject the aqueous - phase mixture in S3 into the outer pipe at a rate of 200 μL / min through the aqueous - phase mixture feed pipe;

[0116] Inject the oil - phase mixture in S5 into the first inner pipe at a rate of 20 μL / min. The aqueous - phase mixture and the oil - phase mixture are mixed at the interval and flow out through the second inner pipe to form emulsion microspheres with a diameter of 40 μm;

[0117] Place the prepared emulsion microspheres at room temperature (25 °C) for volatilization. After the co - solvent chloroform completely volatilizes, the microspheres undergo phase separation to form microspheres with a Janus structure. Due to the action of the surfactant and the two - phase volume ratio, the Janus - structured microspheres have a total internal reflection structural color at this time, that is, magnetic - responsive total internal reflection structural - color microspheres are obtained.

[0118] Place the microspheres with total internal reflection structural color prepared in Example 2 under a magnetic field, control the orientation of the microspheres by adjusting the direction of the externally applied magnetic field, and observe the morphology and color change of the microspheres under a reflection - mode optical microscope.

[0119] As Figure 3 shown,Figure 3 Figure (a) in [0] is an optical microscope image of the Janus microspheres with total internal reflection structural color prepared in step S6 of Example 2, and its color is cyan; Figure 3 Figure (b) in [0] is an optical microscope image of the Janus microspheres with total internal reflection structural color under a deflecting magnetic field. It can be seen that by controlling the direction of the externally applied magnetic field, the Janus microspheres deflect, and their structural color gradually disappears from cyan.

[0120] The above embodiments are only examples. In addition to those shown above, the first surfactant can also be any one of FC-4430, FC301, Capstone 62MA, ZY-FC327, ZY-823, ZONLYFS300, TF282, TF328. These surfactants are similar to Capstone FS-30 and can all preferentially reduce the interfacial tension between fluorocarbons and water; the second surfactant can also be any one of F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, TWEEN 80, CTAB, CTAC. These surfactants are similar to SDS and can all preferentially reduce the interfacial tension between hydrocarbons and water; the specific types of hydrocarbons and fluorocarbons can also be flexibly adjusted as long as they are both liquid at room temperature and immiscible with each other, the density of the hydrocarbons is less than that of the fluorocarbons, and the refractive index is greater than that of the fluorocarbons. The fluorinated monomer can also be one of perfluorohexylphosphonic acid, perfluorooctylphosphonic acid, 1H,1H,2H,2H-perfluorooctane phosphonic acid, bis(perfluorooctyl)phosphonic acid, (perfluoroethyl)phosphonic acid, perfluorododecylphosphonic acid. These fluorinated monomers are similar to (1H,1H,2H,2H-heptadecafluorodecyl)phosphonic acid and perfluorooctylphosphonic acid as long as they contain a phosphoric acid group and fluorine atoms. The phosphoric acid group can enable the fluorinated monomer to be successfully modified on the surface of Fe3O4 nanoparticles, and the fluorine atoms can make the modified Fe3O4 nanoparticles stably and uniformly dispersed in the fluorocarbon. In addition, the preparation process and subsequent detection process of each of the above embodiments are all carried out under room temperature conditions.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing total internal reflection structural color microspheres with magnetic response, characterized in that: The following steps are involved: adding a first surfactant into water to obtain a first surfactant solution; adding a second surfactant into water to obtain a second surfactant solution; Mixing the first surfactant solution and the second surfactant solution to obtain an aqueous phase mixture; The magnetic Fe3O4 particles are added into isopropanol, and then a fluorine-containing monomer is added, and the magnetic Fe3O4 particles are modified by ultrasound, and the modified magnetic Fe3O4 particles are separated; Adding hydrocarbons, fluorocarbons, and modified magnetic Fe3O4 particles into a co-solvent to obtain an oil phase mixture; The aqueous phase mixture and the oil phase mixture are respectively introduced into the microfluidic chip to prepare total internal reflection structural color microspheres with magnetic response; Wherein, the hydrocarbon and the fluorocarbon are immiscible with each other, the density of the hydrocarbon is lower than that of the fluorocarbon, and the refractive index of the hydrocarbon is higher than that of the fluorocarbon; The first surfactant is used to reduce the interfacial tension between the fluorocarbon and water; The second surfactant is used to reduce the interfacial tension between hydrocarbons and water.

2. The method for preparing total internal reflection structural color microspheres with magnetic response according to claim 1, characterized in that: The microfluidic chip comprises: An external pipeline, one end of which is connected to a water phase mixture feed pipe; A first inner pipe, one end of which is sleeved inside the outer pipe and the other end of which extends outside the outer pipe; A second inner pipe, one end of which is sleeved inside the outer pipe and the other end of which extends outside the outer pipe; The first inner pipe and the second inner pipe are distributed on both sides of the outer pipe, and the ends of the first inner pipe and the second inner pipe located in the outer pipe form a gap; The aqueous phase mixture is injected into the outer pipe through the aqueous phase mixture feed pipe, and the oil phase mixture is injected into the first inner pipe. The oil phase mixture is sheared by the aqueous phase mixture at the interval and flows out through the second inner pipe to form emulsion microspheres with uniform size. The co-solvent in the emulsion microspheres evaporates and phase separation occurs to obtain total internal reflection structural color microspheres with magnetic response.

3. The method for preparing total internal reflection structural color microspheres with magnetic response according to claim 1, characterized in that: The first surfactant includes at least one of FC-4430, FC301, Capstone FS-30, Capstone 62MA, ZY-FC327, ZY-823, ZONLYFS300, TF282, and TF328; And / or, the second surfactant includes at least one of SDS, PVA, F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, TWEEN 80, CTAB, and CTAC.

4. The method for preparing total internal reflection structural color microspheres with magnetic response according to claim 1, characterized in that: The hydrocarbon compound comprises at least one of octadecyl methacrylate, ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate, glycidyl methacrylate, tert-butyl bromoacetate, n-butyl acrylate, dodecyl acrylate, and trimethylolpropane triacrylate; And / or, the fluorocarbon compound includes at least one of 1H,1H,2H,2H-heptadecafluorodecyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, hexafluorobutyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, trifluoroethyl methacrylate, perfluoroalkylethyl acrylate, (N-methylperfluorohexylsulfonamido)ethyl acrylate, perfluorooctylethyl acrylate, perfluorohexylethyl methacrylate, perfluoroalkyl acrylate, dodecafluoroheptyl acrylate, perfluoroalkylethyl methacrylate, and perfluoropolyether methacrylate; And / or, the co-solvent includes at least one of chloroform, dichloromethane, n-hexane and toluene; And / or, the fluorine-containing monomer includes at least one of (1H, 1H, 2H, 2H-heptadecafluorodecyl)phosphonic acid, perfluorohexylphosphonic acid, perfluorooctylphosphonic acid, 1H, 1H, 2H, 2H-perfluorooctanephosphonic acid, bis(perfluorooctyl)phosphonic acid, (perfluoroethyl)phosphonic acid, and perfluorododecylphosphonic acid.

5. The method for preparing total internal reflection structural color microspheres with magnetic response according to claim 1, characterized in that: The concentration of the first surfactant solution is 1 to 30 mg / mL; The concentration of the second surfactant solution is 1 to 30 mg / mL; The mass ratio of the first surfactant to the second surfactant is (1-2):

3.

6. The method for preparing total internal reflection structural color microspheres with magnetic response according to claim 1, characterized in that: The magnetic Fe3O4 particles are added to isopropanol, and then a fluorine-containing monomer is added to obtain a mixture, wherein the concentration of the magnetic Fe3O4 particles in the mixture is 1-10 mg / mL, and the concentration of the fluorine-containing monomer is 0.01-0.5 mmol / mL.

7. The method for preparing total internal reflection structural color microspheres with magnetic response according to claim 1, characterized in that: The step of adding hydrocarbons, fluorocarbons, and modified magnetic Fe3O4 particles to a co-solvent, wherein the concentration of the modified magnetic Fe3O4 particles is 0.3 to 3 mg / mL; The volume ratio of the hydrocarbon compound to the fluorocarbon compound is (1:9) to (7:3).

8. The method for preparing total internal reflection structural color microspheres with magnetic response according to claim 1, characterized in that: Injecting the aqueous phase mixture into the outer pipe through the aqueous phase mixture feed pipe at a rate of 50 to 500 μL / min; The oil phase mixture was injected into the first inner channel at a rate of 5-30 μL / min.

9. A total internal reflection structural color microsphere with magnetic response, characterized in that: The preparation is obtained by the preparation method according to any one of claims 1 to 8.

10. Application of the total internal reflection structural color microsphere with magnetic response prepared by the preparation method according to any one of claims 1 to 8 or the total internal reflection structural color microsphere with magnetic response according to claim 9 in intelligent display, anti-counterfeiting material, biological detection, and information encryption.

Images