Preparation method and application of responsive structural color droplets

Abstract

The present invention belongs to the field of responsive structural color materials, and discloses a preparation method and application of responsive structural color droplets, wherein the preparation method specifically includes the following steps: (1) preparing a first surfactant solution and a second surfactant solution; (2) preparing a liquid hydrocarbon and a liquid fluorocarbon as oil phase substances; (3) uniformly mixing the first surfactant solution, the second surfactant solution, the hydrocarbon and the fluorocarbon to form an oil-in-water system, and the formed droplets are responsive structural color droplets; changing the mass ratio of the first surfactant to the second surfactant in the system can make the structural color of the droplets appear or disappear, thereby realizing the response of the structural color to the surfactant. The structural color droplets in the present invention can regulate the morphology of the droplets through the competitive action of the two surfactants, thereby controlling the display and disappearance of the structural color, realizing responsiveness, and are very suitable for anti-counterfeiting.

Description

Technical Field

[0001] The present invention belongs to the field of responsive structural color materials, and more specifically, relates to a preparation method and application of responsive structural color droplets, which have the characteristics of surfactant response. Background Art

[0002] Responsive structural color materials refer to materials that can change color under external stimuli such as temperature, humidity, electric field, magnetic field, etc. It can provide real-time feedback to external stimuli and convert difficult-to-observe external stimuli into optical signals visible to the naked eye. Therefore, responsive structural color materials have great potential in the fields of smart display, anti-counterfeiting, information encryption, biological detection, etc.

[0003] However, currently responsive structural color materials are mainly concentrated in responsive photonic crystal structural color materials. Currently, most of the preparation of photonic crystal materials still adopts a "top-down" strategy, such as lithography and layer-by-layer deposition technology, to prepare large-size materials into the desired micro-nanostructure. Although the "top-down" strategy can be used to prepare a variety of high-quality micro-nanostructures, this method has disadvantages such as high cost, material waste, low time efficiency, and limited structural size, which hinders its application in high-throughput application fields. Therefore, developing new structural color materials and reducing their preparation cycle and cost are of great significance to further expand the application of structural color materials. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide a method for preparing and using responsive structural color droplets, wherein the structure and composition of the droplets are improved and regulated, two different surfactants are used, and the first surfactant, the second surfactant, a hydrocarbon compound and a fluorocarbon compound are used to obtain structural color droplets. The structural color droplets can regulate the morphology of the droplets through the competition of the two surfactants, thereby controlling the display and disappearance of the structural color to achieve responsiveness. The size and color of the structural color droplets obtained by the present invention are random, which can avoid being copied or imitated, and are very suitable for anti-counterfeiting. In addition, the preparation process of the present invention is simple, the raw materials are cheap and can be prepared in batches. In addition, similar to other structural colors, the structural color in the present invention has the advantages of anti-fading, environmental protection, and high saturation.

[0005] To achieve the above object, according to one aspect of the present invention, a method for preparing a responsive structural color droplet is provided, characterized in that it comprises the following steps:

[0006] (1) dissolving a first surfactant in deionized water to obtain a first surfactant solution; dissolving a second surfactant in deionized water to obtain a second surfactant solution; the first surfactant solution and the second surfactant solution correspond to aqueous solutions of a continuous phase of responsive structural color droplets; wherein the first surfactant is one of FC-4430, FC301, Capstone FS-30, Capstone 62MA, ZY-FC327, ZY-823, ZONLY FS300, TF282, and TF328; and the second surfactant is one of SDS, PVA, CTAB, F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, and TWEEN 80;

[0007] (2) preparing a liquid hydrocarbon and a liquid fluorocarbon as oil phase substances; wherein the hydrocarbon has a lower density than the fluorocarbon and a higher refractive index than the fluorocarbon, and the hydrocarbon and the fluorocarbon are immiscible at room temperature; the hydrocarbon and the fluorocarbon are oil phase substances of the dispersed phase of the corresponding responsive structural color droplets;

[0008] (3) uniformly mixing the first surfactant solution, the second surfactant solution, the hydrocarbon compound and the fluorocarbon compound to form an oil-in-water system, wherein the formed droplets are responsive structural color droplets; depending on the mass ratio of the first surfactant to the second surfactant in the system, the droplets can have structural colors or not have structural colors;

[0009] When the mass ratio of the first surfactant to the second surfactant in the oil-in-water system satisfies 1:1 to 1:5, the droplet morphology is a Janus droplet with structural color;

[0010] When the mass ratio of the first surfactant to the second surfactant in the oil-in-water system does not satisfy 1:1 to 1:5, the droplets do not have structural color.

[0011] As a further preferred embodiment of the present invention, the method further comprises step (4):

[0012] When the mass ratio of the first surfactant to the second surfactant in the oil-in-water system satisfies 1:1 to 1:5, by adding the first surfactant solution and / or the second surfactant solution to the oil-in-water system again, so that the mass ratio of the first surfactant to the second surfactant in the system deviates from 1:1 to 1:5, droplets with disappearing structural colors can be obtained by utilizing diffusion.

[0013] When the mass ratio of the first surfactant to the second surfactant in the water-in-oil system does not satisfy 1:1 to 1:5, the first surfactant solution and / or the second surfactant solution are added to the water-in-oil system again so that the mass ratio of the first surfactant to the second surfactant in the system satisfies 1:1 to 1:5 again, and droplets with structural color reproduction can be obtained by utilizing diffusion.

[0014] As a further preferred embodiment of the present invention, in the step (1), the concentration of the first surfactant solution is 1-50 mg / mL, and the concentration of the second surfactant solution is 1-50 mg / mL.

[0015] As a further preferred embodiment of the present invention, in step (2), the hydrocarbon compound is one of octadecyl methacrylate, ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate, tert-butyl bromoacetate, n-butyl acrylate, and dodecyl acrylate;

[0016] The fluorocarbon compound is 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, and trifluoroethyl methacrylate;

[0017] In the step (3), the volume ratio of the hydrocarbon to the fluorocarbon is 1:1 to 1:8.

[0018] As a further preferred embodiment of the present invention, in the step (3), the mixing is carried out in a vortex oscillator at an oscillation speed of 300-2000 rpm and an oscillation time of 0.5-5 min;

[0019] The diameter of the responsive structural color droplet is 20 to 200 μm.

[0020] According to another aspect of the present invention, the present invention provides responsive structural color droplets obtained by the above preparation method.

[0021] According to another aspect of the present invention, the present invention provides the use of the above-mentioned responsive structural color droplets in anti-counterfeiting.

[0022] As a further preferred embodiment of the present invention, the first surfactant solution and / or the second surfactant solution is added again to the water-in-oil system so that the mass ratio of the first surfactant to the second surfactant in the system deviates from or satisfies 1:1 to 1:5, and the disappearance and reappearance of the structural color are controlled by utilizing diffusion.

[0023] Compared with the prior art, the above technical solution conceived by the present invention uses two different surfactants and utilizes the combination of the first surfactant, the second surfactant, the hydrocarbon and the fluorocarbon to obtain responsive structural color droplets.

[0024] The present invention can precisely control the structural color by regulating the morphology of the droplets to achieve responsiveness. The present invention uses FC-4430, FC301, Capstone FS-30, Capstone 62MA, ZY-FC327, ZY-823, ZONLY FS300, TF282, TF328 as the first surfactant, and these first surfactants can preferentially reduce the interfacial tension between fluorocarbons and water; SDS, PVA, CTAB, F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, TWEEN 80 are used as the second surfactant, and these second surfactants can preferentially reduce the interfacial tension between hydrocarbons and water. By controlling the mass ratio of the first surfactant to the second surfactant in the system and utilizing the competitive effect of the first surfactant and the second surfactant, the morphology of the droplets can be changed, and the response of the structural color to the surfactant can be achieved. Specifically, when the mass ratio of the first surfactant to the second surfactant in the system satisfies 1:1-1:5, the morphology of the droplets is Janus droplets with structural color; when the mass ratio of the first surfactant to the second surfactant in the system does not satisfy 1:1-1:5, there is no structural color; in this way, by controlling the mass ratio of the first surfactant to the second surfactant in the system, the structural color of the droplets can be made to appear or disappear, thereby achieving response.

[0025] The droplets in the present invention are composed of immiscible hydrocarbons and fluorocarbons. When the droplets are in the shape of Janus droplets, the droplets can produce structural colors based on total internal reflection and interference mechanisms by utilizing the characteristics that the density of hydrocarbons is lower than that of fluorocarbons but the refractive index is higher than that of fluorocarbons.

[0026] Furthermore, after the water-in-oil system is uniformly mixed, the first surfactant solution and / or the second surfactant solution can be simply added to the system again without further oscillation, and the diffusion effect of the water phase can be used to affect the interface between hydrocarbons and fluorocarbons in the hydrocarbon-fluorocarbon droplets, thereby further changing the morphology of the droplets and causing the structural color of the droplets to disappear or reappear. The structural color droplets with surfactant response obtained by the present invention can display and disappear the structural color by repeatedly changing the mass ratio of the two surfactants to achieve the cycle of display and disappearance of the structural color.

[0027] Specifically, the present invention can achieve the following beneficial effects:

[0028] (1) The method for preparing the structural color droplets provided by the present invention is simple, easy to operate, and has low technical requirements. It can conveniently prepare structural color droplets with controllable micro-nano sizes. The required raw materials are cheap and easy to obtain, and are suitable for large-scale production.

[0029] (2) The structural color droplets obtained by the present invention can realize the display and disappearance of structural colors by adjusting the mass ratio of the two surfactants used. When the mass ratio is 1:1 to 1:5, the droplets display structural colors; and when the mass ratio is outside 1:1 to 1:5, the structural colors disappear, which is suitable for anti-counterfeiting and other fields.

[0030] (3) The structural color droplets prepared by the present invention have the characteristic of being physically non-replicable, and are very suitable for anti-counterfeiting. Taking the formation of an oil-in-water system by oscillation as an example, if the conditions during oscillation change slightly, the overall state of the droplets obtained will change, and they have the characteristic of being physically non-replicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 These are reflection mode optical microscope images of structural color droplets of different sizes prepared by the vortex mixing method in Example 1, and reflection mode optical microscope images of different situations obtained by cyclically adding surfactant 1 and surfactant 2.

[0032] Figure 2 These are reflection mode optical microscope images of droplets of different sizes prepared by the vortex mixing method in Example 2, and reflection mode optical microscope images of different situations obtained by cyclically adding surfactant 1 and surfactant 2.

[0033] Figure 3 These are reflection mode optical microscope images of structural color droplets of different sizes prepared by the vortex mixing method in Example 3, and reflection mode optical microscope images of different situations obtained by cyclically adding surfactant 1 and surfactant 2. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Based on the present invention, the preparation method of structural color droplets with surfactant response can be carried out according to the following steps:

[0036] (1) Prepare a surfactant solution of a certain concentration:

[0037] Prepare a surfactant solution of a certain concentration: dissolve a certain mass of different surfactants (i.e., surfactant 1 and surfactant 2; the difference between the two is that surfactant 1 can preferentially reduce the interfacial tension between fluorocarbons and water, and surfactant 2 can preferentially reduce the interfacial tension between hydrocarbons and water) in a certain volume of deionized water to obtain a continuous phase aqueous solution of responsive structural color droplets, and name them surfactant 1 solution and surfactant 2 solution; surfactant 1 can be one of FC-4430, FC301, Capstone FS-30, Capstone62MA, ZY-FC327, ZY-823, ZONLY FS300, TF282, and TF328, and the concentration of surfactant 1 can be 1-50 mg / mL; surfactant 2 can be one of SDS, PVA, CTAB, F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, and TWEEN 80, and the concentration of surfactant 2 can be 1-50 mg / mL.

[0038] (2) adding a hydrocarbon and a fluorocarbon into a centrifuge tube in a certain volume ratio. The hydrocarbon may be one of octadecyl methacrylate, ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate, tert-butyl bromoacetate, n-butyl acrylate, and dodecyl acrylate;

[0039] The fluorocarbon compound may be 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, and trifluoroethyl methacrylate. The volume ratio of the hydrocarbon compound to the fluorocarbon compound may be 1:1 to 1:8.

[0040] (3) placing a centrifuge tube containing a hydrocarbon and a fluorocarbon in a certain volume ratio in a vortex oscillator, and setting an oscillation speed so that the hydrocarbon and the fluorocarbon can be fully mixed and uniformly obtained to obtain an oil phase substance of a dispersed phase of a responsive structural color droplet. The oscillation speed can be 300-2000 rpm, and the oscillation time can be 0.5-5 min.

[0041] (4) After the hydrocarbon and fluorocarbon are fully mixed, surfactant 1 and surfactant 2 with a certain mass ratio are added to the above solution, and the solution is oscillated again by a vortex oscillator to prepare structural color droplets. The prepared structural color droplet solution system is dropped on a surface dish, and the relationship between color and size is observed under a reflection mode optical microscope. The volume ratio of the oil phase substance to the surfactant solution can be 1:1 to 1:20. The mass ratio of the solute surfactant 1 to the surfactant 2 can be 1:1 to 1:5, and the droplets obtained at this time will show structural color (of course, if the mass ratio of the solute surfactant 1 to the surfactant 2 deviates from 1:1 to 1:5, the droplets obtained do not have structural color, and the structural color can be restored later by adjusting the mass ratio of the solute surfactant 1 to the surfactant 2). The diameter of the structural color droplet is 20 to 200 μm.

[0042] The above preparation process is based on the mixing of the oil phase materials in step (3) and step (4) to form an oil-in-water system. In addition to the mixing in steps, the two surfactant aqueous solutions and the two oil phase materials can also be added to the same centrifuge tube at one time, so that a uniformly mixed oil-in-water system can be obtained by a single shaking treatment. In addition, in addition to using a vortex shaker to achieve mixing, other mixing methods such as hand shaking, ultrasonic mixing, cell crusher treatment, etc. can also be used.

[0043] Furthermore, in order to detect the responsiveness of the droplet, the following steps can be performed:

[0044] S1: Add a certain amount of surfactant 2 to the droplet solution system that has produced structural color, and observe the droplet morphology and color changes through a reflection mode optical microscope. The mass of the surfactant 2 added again needs to make the mass ratio of the solute surfactant 1 to the surfactant 2 of the whole system outside the range of 1:1 to 1:5.

[0045] S2: Add a certain amount of surfactant 1 to the droplet solution system obtained in step S1 again, and observe the change of droplet morphology and color by reflection mode optical microscope. The mass of the surfactant 1 added again needs to make the mass ratio of the solute surfactant 1 to the surfactant 2 in the whole system meet the range of 1:1 to 1:5.

[0046] S3: Repeat steps S1 and S2 in sequence, and observe the droplet morphology and color changes through a reflection mode optical microscope. The number of repeated cycles can reach more than 8 times.

[0047] Of course, in addition to first adding surfactant 2 to the system and then adding surfactant 1 in the above steps S1 and S2, surfactant 1 can also be added first to make the mass ratio of solute surfactant 1 to surfactant 2 deviate from 1:1 to 1:5, and then surfactant 2 is added to restore the mass ratio of solute surfactant 1 to surfactant 2 to meet 1:1 to 1:5.

[0048] The following are specific embodiments:

[0049] Example 1

[0050] The structural color droplets in this embodiment are prepared according to the following method:

[0051] (1) Prepare a surfactant solution of a certain concentration:

[0052] A certain mass of Capstone FS-30 is dissolved in a certain volume of deionized water, and the concentration of the obtained Capstone FS-30 aqueous solution (i.e., surfactant 1 solution) is 15 mg / mL; a certain mass of SDS is dissolved in a certain volume of deionized water, and the concentration of the obtained SDS aqueous solution (i.e., surfactant 2 solution) is 10 mg / mL; surfactant 1 solution and surfactant 2 solution can be used as aqueous solutions of the continuous phase of structural color droplets.

[0053] (2) Adding ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H-heptadecafluorodecyl acrylate into a centrifuge tube in a certain volume ratio, wherein the volume ratio of ethoxylated trimethylolpropane triacrylate to 1H,1H,2H,2H-heptadecafluorodecyl acrylate is 1:1.

[0054] (3) A centrifuge tube containing ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H-heptadecafluorodecyl acrylate in a volume ratio of 1:1 was placed in a vortex oscillator, and the oscillation speed was set to 500 rpm and the oscillation time was set to 1 min, so that the ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H-heptadecafluorodecyl acrylate can be fully mixed to obtain the oil phase material of the dispersed phase of the structural color droplets.

[0055] (4) After the ethoxylated trimethylolpropane triacrylate and 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate are fully mixed, a Capstone FS-30 aqueous solution and an SDS aqueous solution having a certain mass ratio are added to the above solution, and the solution is oscillated again by a vortex oscillator to prepare structural color droplets. The prepared structural color droplet solution system is dropped onto a surface dish, and the relationship between color and size is observed under a reflection mode optical microscope. The volume ratio of the oil phase substance to the surfactant solution is 1:5 (wherein the volume of the surfactant solution is the algebraic sum of the volumes of the surfactant 1 solution and the surfactant 2 solution used in this step), the mass ratio of the solute Capstone FS-30 to SDS is 1:2, and the diameter of the structural color droplet is 40 to 150 μm.

[0056] (5) A certain amount of Capstone FS-30 aqueous solution is added again to the droplet solution system that has produced structural color, and the droplet morphology and color changes are observed by reflection mode optical microscopy. The mass of the Capstone FS-30 added again is required to make the mass ratio of the solute Capstone FS-30 to SDS in the whole system be 2:1.

[0057] (6) A certain amount of SDS aqueous solution is added again to the droplet solution system obtained in step (5), and the droplet morphology and color changes are observed by reflection mode optical microscopy. The mass of the SDS added again is required to make the mass ratio of the solute Capstone FS-30 to SDS in the whole system be 1:2.

[0058] (7) Repeat steps (5) and (6) in sequence, and observe the change of the droplet morphology and color through a reflection mode optical microscope. The number of repetitions is more than 8 times.

[0059] like Figure 1 As shown, Figure 1 (a) is an optical microscope image of the structural color obtained in step (4), where the mass ratio of solute Capstone FS-30 to SDS is 1:2; Figure 1 (b) is an optical microscope image after a certain amount of Capstone FS-30 aqueous solution is added in step (5) (the mass of Capstone FS-30 added again at this time makes the mass ratio of solute Capstone FS-30 to SDS in the whole system be 2:1). It can be seen that the structural color has disappeared. Figure 1(c) is an optical microscope image after a certain amount of SDS aqueous solution is added in step (6) (at this time, the mass of SDS added again makes the mass ratio of solute Capstone FS-30 to SDS in the whole system 1:2). It can be seen that the structural color reappears, and the cycle is repeated. The number of cycles can reach more than 8 times.

[0060] Example 2

[0061] The structural color droplets in this embodiment are prepared according to the following method:

[0062] (1) Prepare a surfactant solution of a certain concentration:

[0063] A certain mass of Capstone FS-30 is dissolved in a certain volume of deionized water, and the concentration of the obtained Capstone FS-30 aqueous solution (i.e., surfactant 1 solution) is 10 mg / mL; a certain mass of SDS is dissolved in a certain volume of deionized water, and the concentration of the obtained SDS aqueous solution (i.e., surfactant 2 solution) is 20 mg / mL; surfactant 1 solution and surfactant 2 solution can be used as aqueous solutions of the continuous phase of structural color droplets.

[0064] (2) Adding ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H-heptadecafluorodecyl acrylate into a centrifuge tube in a certain volume ratio, wherein the volume ratio of ethoxylated trimethylolpropane triacrylate to 1H,1H,2H,2H-heptadecafluorodecyl acrylate is 1:2.

[0065] (3) A centrifuge tube containing ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H-heptadecafluorodecyl acrylate in a volume ratio of 1:2 is placed in a vortex oscillator, and the oscillation speed is set to 600 rpm and the oscillation time is set to 1 min, so that the ethoxylated trimethylolpropane triacrylate and 1H,1H,2H,2H-heptadecafluorodecyl acrylate can be fully mixed to obtain the oil phase substance of the dispersed phase of the structural color droplets.

[0066] (4) After the ethoxylated trimethylolpropane triacrylate and 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate are fully mixed, a Capstone FS-30 aqueous solution and an SDS aqueous solution having a certain mass ratio are added to the above solution, and the droplets are prepared by vortexing again. The prepared droplet solution system is dropped on a surface dish and observed under a reflection mode optical microscope. The volume ratio of the oil phase substance to the surfactant solution is 1:4 (wherein the volume of the surfactant solution is the algebraic sum of the volumes of the surfactant 1 solution and the surfactant 2 solution used in this step), the mass ratio of the solute Capstone FS-30 to SDS is 3:1, and the diameter of the droplet is 50 to 100 μm.

[0067] (5) A certain amount of SDS aqueous solution is added to the above droplet solution system again, and the droplet morphology and color changes are observed by reflection mode optical microscopy. The mass of the SDS added again is required to make the mass ratio of the solute Capstone FS-30 to SDS in the whole system be 1:3.

[0068] (6) Add a certain amount of Capstone FS-30 aqueous solution to the droplet solution system obtained in step (5), and observe the droplet morphology and color changes by reflection mode optical microscopy. The mass of the Capstone FS-30 added again needs to make the mass ratio of the solute Capstone FS-30 to SDS in the whole system be 3:1.

[0069] (7) Repeat steps (5) and (6) in sequence, and observe the morphology and color changes of the droplets through a reflection mode optical microscope. The number of repeated cycles is more than 10 times.

[0070] like Figure 2 As shown, Figure 2 (a) is an optical microscope image of a droplet obtained in step (4) without producing structural color, where the mass ratio of solute Capstone FS-30 to SDS is 3:1; Figure 2 (b) is an optical microscope image after a certain amount of SDS aqueous solution is added in step (5) (at this time, the mass of SDS added again needs to make the mass ratio of solute Capstone FS-30 and SDS in the whole system be 1:3). It can be seen that the droplets produce structural colors. Figure 2(c) is an optical microscope image after a certain amount of Capstone FS-30 aqueous solution is added in step (6) (at this time, the mass of Capstone FS-30 added again needs to make the mass ratio of solute Capstone FS-30 to SDS in the whole system 3:1). It can be seen that the structural color disappears again, and the cycle is repeated. The number of cycles can reach more than 10 times.

[0071] Example 3

[0072] The structural color droplets in this embodiment are prepared according to the following method:

[0073] (1) Prepare a surfactant solution of a certain concentration:

[0074] A certain mass of Capstone FS-30 is dissolved in a certain volume of deionized water, and the concentration of the obtained Capstone FS-30 aqueous solution (i.e., surfactant 1 solution) is 20 mg / mL; a certain mass of PVA is dissolved in a certain volume of deionized water, and the concentration of the obtained PVA aqueous solution (i.e., surfactant 2 solution) is 15 mg / mL; surfactant 1 solution and surfactant 2 solution can be used as aqueous solutions of the continuous phase of structural color droplets.

[0075] (2) Adding ethoxylated trimethylolpropane triacrylate and 2,2,2-trifluoroethyl methacrylate into a centrifuge tube according to a certain volume ratio, wherein the volume ratio of ethoxylated trimethylolpropane triacrylate to 2,2,2-trifluoroethyl methacrylate is 1:1.

[0076] (3) placing a centrifuge tube containing ethoxylated trimethylolpropane triacrylate and 2,2,2-trifluoroethyl methacrylate in a volume ratio of 1:1 in a vortex oscillator, setting the oscillation speed to 500 rpm and the oscillation time to 1 min, so that the ethoxylated trimethylolpropane triacrylate and 2,2,2-trifluoroethyl methacrylate can be fully mixed and uniformly obtained to obtain the oil phase material of the dispersed phase of the structural color droplets.

[0077] (4) After the ethoxylated trimethylolpropane triacrylate and 2,2,2-trifluoroethyl methacrylate are fully mixed, a Capstone FS-30 aqueous solution and a PVA aqueous solution having a certain mass ratio are added to the above solution, and the structural color droplets are prepared by vortexing again. Drop the prepared structural color droplet solution system on a watch glass, and observe the relationship between color and size under a reflection mode optical microscope. The volume ratio of the oil phase substance to the surfactant solution is 1:5 (wherein the volume of the surfactant solution is the algebraic sum of the volumes of the surfactant 1 solution and the surfactant 2 solution used in this step), the mass ratio of the solute Capstone FS-30 to PVA is 2:3, and the diameter of the structural color droplet is 40 to 120 μm.

[0078] (5) A certain amount of Capstone FS-30 aqueous solution is added again to the droplet solution system that has produced structural color, and the droplet morphology and color changes are observed by reflection mode optical microscopy. The mass of the Capstone FS-30 added again is required to make the mass ratio of the solute Capstone FS-30 to PVA in the whole system be 2:1.

[0079] (6) A certain amount of PVA aqueous solution is added to the droplet solution system obtained in step (5), and the droplet morphology and color changes are observed by reflection mode optical microscopy. The mass of the PVA added again is required to make the mass ratio of the solute Capstone FS-30 to PVA in the whole system be 2:3.

[0080] (7) Repeat steps (5) and (6) in sequence, and observe the morphology and color changes of the droplets through a reflection mode optical microscope. The number of repeated cycles is more than 10 times.

[0081] like Figure 3 As shown, Figure 3 (a) is an optical microscope image of the structural color obtained in step (4), where the mass ratio of solute Capstone FS-30 to PVA is 2:3; Figure 3 (b) is an optical microscope image after a certain amount of Capstone FS-30 aqueous solution is added in step (5) (at this time, the mass of Capstone FS-30 added again needs to make the mass ratio of solute Capstone FS-30 to PVA in the whole system be 2:1). It can be seen that the structural color has disappeared. Figure 3(c) is an optical microscope image after a certain amount of PVA aqueous solution is added in step (6) (at this time, the mass of PVA added again needs to make the mass ratio of solute Capstone FS-30 to PVA in the whole system 2:3). It can be seen that the structural color reappears, and the cycle is repeated. The number of cycles can reach more than 10 times.

[0082] The above embodiments are only examples. In addition to the above examples, surfactant 1 can also be any one of FC-4430, FC301, Capstone 62MA, ZY-FC327, ZY-823, ZONLY FS300, TF282, and TF328. These surfactants are similar to Capstone FS-30 and can preferentially reduce the interfacial tension between fluorocarbons and water. Surfactant 2 can also be any one of CTAB, F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, and TWEEN 80. These surfactants are similar to SDS and PVA and can 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 liquid at room temperature and are incompatible with each other, the density of hydrocarbons is less than that of fluorocarbons, and the refractive index is greater than that of fluorocarbons. In addition, the preparation process and subsequent detection process of each of the above embodiments are carried out at room temperature.

[0083] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a responsive structural color droplet, characterized in that: The following steps are involved: (1) dissolving a first surfactant in deionized water to obtain a first surfactant solution; dissolving a second surfactant in deionized water to obtain a second surfactant solution; the first surfactant solution and the second surfactant solution correspond to aqueous solutions of a continuous phase of responsive structural color droplets; wherein the first surfactant is one of FC-4430, FC301, Capstone FS-30, Capstone 62MA, ZY-FC327, ZY-823, ZONLY FS300, TF282, and TF328; and the second surfactant is one of SDS, PVA, CTAB, F-108, F-127, TWEEN 20, TWEEN 40, TWEEN 60, and TWEEN 80; (2) preparing a liquid hydrocarbon and a liquid fluorocarbon as oil phase substances; wherein the hydrocarbon has a lower density than the fluorocarbon and a higher refractive index than the fluorocarbon, and the hydrocarbon and the fluorocarbon are immiscible at room temperature; the hydrocarbon and the fluorocarbon are oil phase substances of the dispersed phase of the corresponding responsive structural color droplets; (3) uniformly mixing the first surfactant solution, the second surfactant solution, the hydrocarbon compound and the fluorocarbon compound to form an oil-in-water system, wherein the formed droplets are responsive structural color droplets; depending on the mass ratio of the first surfactant to the second surfactant in the system, the droplets can have structural colors or not have structural colors; When the mass ratio of the first surfactant to the second surfactant in the oil-in-water system satisfies 1:1 to 1:5, the droplet morphology is a Janus droplet with structural color; When the mass ratio of the first surfactant to the second surfactant in the water-in-oil system does not satisfy 1:1 to 1:5, the droplets do not have structural color; Wherein, in the step (2), the hydrocarbon compound is one of octadecyl methacrylate, ethoxylated trimethylolpropane triacrylate, ethylene glycol dimethacrylate, tert-butyl bromoacetate, n-butyl acrylate, and dodecyl acrylate; The fluorocarbon compound is 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, and trifluoroethyl methacrylate; In the step (3), the volume ratio of the hydrocarbon to the fluorocarbon is 1:1 to 1:

8.

2. The method for preparing a responsive structural color droplet according to claim 1, characterized in that: The method further comprises step (4): When the mass ratio of the first surfactant to the second surfactant in the oil-in-water system satisfies 1:1 to 1:5, by adding the first surfactant solution and / or the second surfactant solution to the oil-in-water system again, so that the mass ratio of the first surfactant to the second surfactant in the system deviates from 1:1 to 1:5, droplets with disappearing structural colors can be obtained by utilizing diffusion. When the mass ratio of the first surfactant to the second surfactant in the water-in-oil system does not satisfy 1:1 to 1:5, the first surfactant solution and / or the second surfactant solution are added to the water-in-oil system again so that the mass ratio of the first surfactant to the second surfactant in the system satisfies 1:1 to 1:5 again, and droplets with structural color reproduction can be obtained by utilizing diffusion.

3. The method for preparing a responsive structural color droplet according to claim 1, characterized in that: In the step (1), the concentration of the first surfactant solution is 1-50 mg / mL, and the concentration of the second surfactant solution is 1-50 mg / mL.

4. The method for preparing a responsive structural color droplet according to claim 1, characterized in that: In the step (3), the mixing is carried out in a vortex oscillator at a shaking speed of 300-2000 rpm and a shaking time of 0.5-5 min; The diameter of the responsive structural color droplet is 20 to 200 μm.

5. A responsive structural color droplet obtained by the preparation method according to any one of claims 1 to 4.

6. Application of the responsive structural color droplet as claimed in claim 5 in anti-counterfeiting.

7. The use according to claim 6, characterized in that Specifically, the first surfactant solution and / or the second surfactant solution is added again to the water-in-oil system so that the mass ratio of the first surfactant to the second surfactant in the system deviates from or meets 1:1 to 1:5, and the disappearance and reappearance of the structural color are controlled by utilizing the diffusion effect.

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