WO2022032977A1 - Method for visualizing complex magnetic field - Google Patents

Method for visualizing complex magnetic field Download PDF

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WO2022032977A1
WO2022032977A1 PCT/CN2020/142003 CN2020142003W WO2022032977A1 WO 2022032977 A1 WO2022032977 A1 WO 2022032977A1 CN 2020142003 W CN2020142003 W CN 2020142003W WO 2022032977 A1 WO2022032977 A1 WO 2022032977A1
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magnetic field
magnetic
color
nanoparticles
detection device
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PCT/CN2020/142003
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French (fr)
Chinese (zh)
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何乐
李超然
陈志杰
李海
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苏州大学
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/032—Measuring direction or magnitude of magnetic fields or magnetic flux using magneto-optic devices, e.g. Faraday or Cotton-Mouton effect
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/10—Plotting field distribution ; Measuring field distribution

Definitions

  • the invention relates to the technical field of materials, in particular to a method for visualizing a complex magnetic field.
  • the geomagnetic field is one of the important conditions for the evolution of life. In nature, animals such as birds and fish have the ability to detect the Earth's magnetic field and use it for orientation and navigation. Although the magnetic field is invisible and untouchable, human beings have not stopped exploring, learning and using the magnetic field. The existence of magnetism was not realized until the 6th century BC. Over the next few centuries, people gradually learned how to use magnetic fields, the advent of the compass ushered in the age of navigation, and the technology of electromagnetic power generation drove the second industrial revolution. Today, the applications of magnetism have expanded to various fields such as information, transportation, medicine, security, energy, materials, biology, geology, oceanography, and space. But visualizing complex magnetic fields has always been a difficult problem to solve, and research on detecting magnetic fields has never stopped. Now compare the existing detection technology:
  • a compass can be used to indicate the direction of the magnetic field, and a magnetometer can be used to detect the magnitude of the magnetic field.
  • the current detection methods still have some defects.
  • the most common way to visualize the distribution of magnetic field lines is to use iron filings, but the accumulation of iron filings under the influence of a magnetic field results in a loss of resolution.
  • Magnetically responsive photonic crystals can respond to external magnetic field stimuli and can be used in the field of magnetic field detection.
  • Zhou reported the use of polyacrylic acid-terminated Fe 3 O 4 colloidal nanocrystal clusters (CNC) for magnetic detection (Scientific Reports, 2015, 5, 17063);
  • Zhang reported the use of ellipsoidal Fe 3 O 4 @SiO 2 Colloidal nanosolutions can detect weak magnetic fields down to 4.5 Gauss (J.Mater.Chem.C, 2018, 6, 5528).
  • CNC colloidal nanocrystal clusters
  • the technical problem to be solved by the present invention is to provide a method for visualizing a complex magnetic field.
  • the method of the present invention can detect the direction and angle of the complex magnetic field and has high spatial and temporal resolution.
  • the present invention provides a method for visualizing a complex magnetic field, comprising:
  • the detection device is placed on the magnetic field to be measured, and the direction and distribution of the magnetic field can be judged according to the displayed color and pattern;
  • the magnetic monodisperse particles are magnetic nanoparticles whose surfaces are coated with a SiO 2 layer;
  • the magnetic nanoparticle The shape of the particles is rod, ellipsoid, spherical cylinder or sheet;
  • the magnetic material is one or more of Fe 3 O 4 and Ni.
  • the magnetic monodisperse particles are rod-shaped Fe 3 O 4 @SiO 2 or flake-shaped Ni@SiO 2 .
  • the long-axis size of the magnetic monodisperse particles is 150-180 nm, and the short-axis size is 30-40 nm.
  • the thickness of the SiO 2 layer is 15-80 nm.
  • the solvent is selected from one or more of water, acetonitrile, ethanol or ethylene glycol; the mass concentration of the magnetic nanoparticles is 10% to 24%.
  • the PDMS device is specifically:
  • the judgment is to judge the direction and angle of the magnetic field, specifically:
  • the angle of the nanoparticle under the specific wavelength or color is calculated;
  • the direction of the magnetic field is determined by the closed curve connected by the above-mentioned multiple angles.
  • the judgment is to judge whether the magnetic field is defective, specifically:
  • the device color pattern differs from that exhibited by being placed over a known defect-free magnetic field, the magnetic field is defective, otherwise, there is no defect.
  • the judgment is to detect a rotating magnetic field, specifically:
  • the above detection device is placed on a magnetic stirrer, and the pattern changes of each frame in a cycle are observed, thereby detecting the rotating magnetic field.
  • the rotational speed of the magnetic stirrer is 1-20 r/s.
  • the present invention provides a method for visualizing a complex magnetic field, comprising: dispersing magnetic monodisperse particles in a solvent, encapsulating them in a PDMS device to obtain a detection device; placing the detection device in a waiting On the magnetic field measurement, the direction and distribution of the magnetic field can be judged according to the color and pattern presented; the magnetic monodisperse particles are magnetic nanoparticles whose surface is coated with a SiO layer ; the shape of the magnetic nanoparticles is rod-like, ellipsoid , spherical cylinder or sheet; the magnetic material is one or more of Fe 3 O 4 and Ni.
  • the present invention applies the prepared device containing the magnetic nanorod solution in the vicinity of a complex magnetic field.
  • the direction and distribution of the complex magnetic field can be directly judged by the naked eye through the color and pattern.
  • the method is simple, non-toxic, low in cost, high in sensitivity, high in resolution and reusable.
  • Fig. 1 is the schematic diagram of visual detection equipment of the present invention
  • Fig. 2 is the magnetic field measurement result graph in the embodiment 1 of the present invention.
  • Figure 3 shows the reflection spectra of nanorods under different magnetic fields
  • Embodiment 4 is a result diagram of detecting magnetic field defects in Embodiment 4 of the present invention.
  • Example 5 is a microscope image obtained by enlarging the pattern area in Example 4 of the present invention.
  • FIG. 6 is the pattern of the number of adjacent frames in the video of the pattern change of the visualization device on the rotating magnetic field of 1 r/s in the fifth embodiment of the present invention.
  • the present invention provides a method for visualizing a complex magnetic field, and those skilled in the art can learn from the content of this article and appropriately improve the process parameters for realization. It should be particularly pointed out that all similar replacements and modifications are obvious to those skilled in the art, and they all belong to the protection scope of the present invention.
  • the method and application of the present invention have been described through the preferred embodiments, and it is obvious that relevant persons can make changes or appropriate changes and combinations of the methods and applications herein without departing from the content, spirit and scope of the present invention to realize and apply the present invention. Invention technology.
  • the present invention provides a method for visualizing a complex magnetic field, comprising:
  • the detection device is placed on the magnetic field to be measured, and the direction and distribution of the magnetic field can be judged according to the displayed color and pattern;
  • the magnetic monodisperse particles are magnetic nanoparticles whose surfaces are coated with a SiO 2 layer;
  • the magnetic nanoparticle The shape of the particles is rod, ellipsoid, spherical cylinder or sheet;
  • the magnetic material is one or more of Fe 3 O 4 and Ni.
  • the method of visualizing a complex magnetic field provided by the present invention first dissolves magnetic monodisperse particles in a solvent.
  • the magnetic monodisperse particles of the present invention are magnetic nanoparticles whose surfaces are coated with a SiO 2 layer; the shape of the magnetic nanoparticles is a rod, an ellipsoid, a spherical cylinder or a sheet; has a certain orientation.
  • the magnetic material is one or more of Fe 3 O 4 and Ni.
  • the magnetic monodisperse particles are preferably rod-shaped Fe 3 O 4 @SiO 2 or flake-shaped Ni@SiO 2 .
  • the size of the long axis of the magnetic monodisperse particles is 150-180 nm, and the size of the short axis is 30-40 nm.
  • the thickness of the SiO 2 layer is 15-80 nm. It is preferably 30 to 65 nm.
  • the solvent is selected from one or more of water, acetonitrile, ethanol or ethylene glycol, preferably water; the magnetic substance has good dispersibility in water, and after the magnetic substance is dispersed in water, a high dispersibility is formed. magnetic substance dispersion.
  • the mass concentration of the magnetic nanoparticles is 10%-24%; preferably, it is 15%-20%.
  • the present invention also provides a preparation method of the above-mentioned magnetic monodisperse particles, comprising the following steps:
  • step B) calcining the reaction product obtained in step B) under a reducing atmosphere to obtain a magnetic substance
  • the nanoparticles are selected from ⁇ -Fe 2 O 3 nanoparticles, FeOOH nanoparticles, and Ni(OH) 2 nanoparticles.
  • the ⁇ -Fe 2 O 3 nanoparticles are prepared as follows:
  • the water-soluble iron source compound and sodium dihydrogen phosphate are dissolved in water, and the heating reaction is carried out to obtain ⁇ -Fe 2 O 3 nanoparticles.
  • the water-soluble iron source compound is selected from ferric chloride hexahydrate.
  • the temperature of the heating reaction was 100° C., and the time of the heating reaction was 48 h.
  • the morphology of ⁇ -Fe 2 O 3 nanoparticles can be controlled by adjusting the type and addition amount of the morphology control agent in the reaction solution.
  • the FeOOH nanoparticles are prepared as follows:
  • the water-soluble iron source compound is dissolved in water, the pH value is adjusted, and the heating reaction is performed to obtain FeOOH nanoparticles.
  • the water-soluble iron source compound is selected from ferric chloride hexahydrate.
  • the temperature of the heating reaction is 90-100°C, and the time of the heating reaction is 4-10 hours.
  • the pH value is between 1.2 and 1.94, and magnetic particles of different sizes and shapes can be obtained.
  • the lower the reaction pH the longer the length, the smaller the diameter, and the larger the aspect ratio.
  • the iron-containing nanoparticles are preferably prepared according to the methods of hydrolysis of iron salts in documents Nat.Mater.2008, 7, 242-247 and J.Am.Chem.Soc.
  • Ni(OH) 2 nanoparticles are prepared as follows:
  • the modifier used for modification is selected from PAA or PVP.
  • the iron-containing nanoparticles can be mixed with orthosilicic acid. Tetraethyl ester binding.
  • the preparation method of the modified iron-containing nanoparticles is:
  • the iron-containing nanoparticle dispersion liquid and the solution containing the modifier are mixed and stirred to obtain modified iron-containing nanoparticles.
  • the nanoparticles are dispersed in water and then added to ethanol to obtain a dispersion liquid of modified iron-containing nanoparticles.
  • the catalyst is added to the dispersion and mixed, and the mixing mode is preferably ultrasonic mixing;
  • the temperature of the reaction is a normal temperature condition, and in the present invention, the normal temperature is defined as 25 ⁇ 5°C.
  • the mass-volume ratio of the magnetic nanoparticles to tetraethyl orthosilicate is 30 mg: 200 ⁇ L.
  • the reaction product of the above reaction is calcined in a reducing atmosphere to obtain a magnetic substance.
  • the reducing atmosphere is selected from hydrogen.
  • the iron-containing nanoparticles are FeOOH
  • the calcination temperature is 350° C.
  • the nanoparticles are ⁇ -Fe 2 O 3
  • the calcination temperature is 400 °C.
  • the nanoparticles are Ni(OH) 2
  • the calcination temperature is 300°C. Under this temperature condition, the properties of the obtained magnetic substance are significantly better than the magnetic monodisperse particles obtained under other temperature conditions.
  • the PDMS device of the present invention is specifically: PDMS provided with grooves; and a glass sheet compounded on the PDMS.
  • the present invention does not limit the shape and specification of the groove, preferably a circular groove, and the specific specification is preferably a circular groove with a diameter of 4 cm.
  • the detection device is placed on the magnetic field to be measured, and the direction and distribution of the magnetic field can be determined according to the colors and patterns presented on the device.
  • the complex magnetic field described in the present invention can be of various types, including rotating magnetic fields, and in addition, the magnetic field strength can be as low as 50 Gauss.
  • the determination is to determine the direction and angle of the magnetic field, specifically:
  • the angle of the nanoparticle under the specific wavelength or color is calculated;
  • the direction of the magnetic field is determined by the closed curve connected by the above-mentioned multiple angles.
  • the photonic structure has different reflection spectra under the magnetic field in different directions; the color of the magnetic nanorod structure can be adjusted by changing the angle between the magnetic field and the nanorod colloidal crystal solution.
  • the reflectance spectrum was measured using a Ocean Optics DH2000BAL-UV-NIR spectrometer.
  • the specific performance is that the detection device is placed on the microscope stage, and the orientation of the nanoparticles is changed by adjusting the direction of the magnetic field, thereby obtaining the color of the colloidal solution of the nanoparticles, and obtaining the corresponding reflection spectrum.
  • the angle of the nanoparticle under the specific wavelength or color is calculated;
  • the prepared detection device is placed above the magnetic field, and the displayed pattern is the magnetic field angle pattern at 1 mm above the magnetic field. According to the one-to-one correspondence between structural color and magnetic field angle, the angle of a specific point can be obtained from the color. Since the magnetic induction line is closed, we can judge the distribution of the magnetic field direction through multiple angles.
  • the judgment is to judge whether the magnetic field is defective, specifically:
  • the device color pattern differs from that exhibited by being placed over a known defect-free magnetic field, the magnetic field is defective; otherwise, there is no defect.
  • the gray area in the middle is a magnet.
  • the surface of this magnet appears smooth and flawless.
  • the color pattern is staggered colored lines. If a point is magnetized, it will show a little space or bulge. If a line in the area is magnetized, the staggered colored lines break and a new line is created. If an area is magnetized, the colored lines in that area disappear and a large pattern is created. Therefore the method can be used to detect defects in magnetic fields.
  • the inventors can find that the spatial resolution can reach 10 ⁇ m, which proves that the method has high spatial resolution.
  • the determination is to detect a rotating magnetic field, specifically:
  • the above detection device is placed on a magnetic stirrer, and the pattern changes of each frame in a cycle are observed, thereby detecting the rotating magnetic field.
  • the invention detects the rotating magnetic field and has high time resolution.
  • the detection device was placed above the 1r/s magnetic stirrer, it showed periodic pattern changes.
  • the inventors intercepted the pattern of each frame in a cycle, and the pattern is very clear, and the pattern difference between adjacent frames is obvious, indicating that the temporal resolution is also high.
  • Magnetic fields can be detected in a wide range.
  • the particles are all inorganic materials, and the constituent elements (iron, silicon, oxygen) are non-toxic.
  • the method has high spatiotemporal resolution.
  • the present invention provides a method for visualizing a complex magnetic field, comprising: dissolving magnetic monodisperse particles in a solvent and encapsulating them in a PDMS device to obtain a detection device; placing the detection device on the magnetic field to be measured,
  • the magnetic monodisperse particles can judge the direction and distribution of the magnetic field according to the color and pattern presented by the light; the magnetic monodisperse particles are magnetic nanoparticles whose surface is covered with a SiO 2 layer; the shape of the magnetic nanoparticles is rod-like, Ellipsoid, spherical cylinder or sheet; the magnetic material is one or more of Fe 3 O 4 and Ni.
  • the prepared device containing the magnetic nanorod solution is applied near the complex magnetic field, and the direction and distribution of the complex magnetic field can be directly judged by the naked eye through the color and pattern.
  • the method is simple, non-toxic, low in cost, high in sensitivity and high in resolution. ,reusable.
  • the square glass and the round coverslip were bonded together with a UV curing agent, and then placed in a petri dish, and 8 g of the silicone elastic prepolymer and 1.5 g of the curing agent were mixed uniformly into the petri dish.
  • the petri dishes were then placed in an oven at 60°C for 2 hours to cure to obtain polydimethoxysilane (PDMS) with a special shape.
  • PDMS polydimethoxysilane
  • the cured PDMS was cut along the edge of the square glass and taken out, and two holes were punched at the edge of the PDMS sheet groove with a needle.
  • the PDMS sheet and the glass sheet were then bonded together using a plasma cleaner to obtain the desired equipment.
  • the Fe 3 O 4 @SiO 2 nanorod solution prepared in step 1 is injected into the device prepared in step 2, which is a device for detecting magnetic field (as shown in FIG. 1 , which is a schematic diagram of the visual detection equipment of the present invention).
  • FIG. 1 which is a schematic diagram of the visual detection equipment of the present invention.
  • FIG. 2 is a diagram of the measurement result of the magnetic field in Example 1 of the present invention; the diagram shows that the visualization device is placed on the complex magnetic field, and a pattern indicating the direction of the complex magnetic field can be displayed.
  • the ellipsoidal Fe 3 O 4 @SiO 2 solution was injected into the device to display a specific pattern, thereby judging the direction and distribution of the complex magnetic field.
  • the reflectance spectrum was measured using a Ocean Optics DH2000BAL-UV-NIR spectrometer.
  • the specific performance is that the visual detection device is placed on the microscope stage, and the orientation of the nanoparticles is changed by adjusting the direction of the magnetic field, thereby changing the color of the colloidal solution of the nanoparticles, and obtaining the corresponding reflection spectrum. (See Figure 1 for the detection device)
  • Figure 3 shows the reflection spectra of nanorods under different magnetic fields.
  • (a) is a schematic diagram of adjusting the color of the magnetic nanorod structure by changing the angle between the magnetic field and the nanorod colloidal crystal solution.
  • (b) is the reflection spectrum of the photonic structure under different magnetic fields.
  • (c) is the reflection spectrum of the photonic structure under different magnetic fields. (The volume fraction of nanorods in this example is 20%, and different concentrations produce different ranges of reflected light.)
  • the orientation of the nanorods in the solution changes with the change of the magnetic field direction, and does not respond to the change of the magnetic field strength. Therefore, the angle of the magnetic field can be judged by judging the structural color of the nanorod colloidal solution.
  • the magnetic field angle at a specific wavelength can be obtained by calculation.
  • the prepared detection device was placed above the magnetic field, and the displayed pattern was the magnetic field angle pattern at 1 mm above the magnetic field. According to the one-to-one correspondence between structural color and magnetic field angle, the angle of a specific point can be obtained from the color. Since the magnetic induction line is closed, we can judge the distribution of the magnetic field direction through multiple angles.
  • the pattern can be used to judge whether the magnetic field has defects.
  • Fig. 4 is a result diagram of detecting magnetic field defects in Example 4 of the present invention.
  • the gray area in the middle is a magnet.
  • the surface of this magnet appears smooth and flawless.
  • the color pattern is staggered colored lines ( Figure a). If a point is magnetized, it will show a little space or a convex point, as shown in Figures b and c. If a line in this area is magnetized, the interlaced colored lines break and a new line is created (Fig. d). If an area is magnetized, the colored lines in that area disappear and a large pattern is created (Fig. e, f). Therefore the method can be used to detect defects in magnetic fields.
  • FIG. 5 is observed with a microscope
  • FIG. 5 is a microscope image obtained by enlarging the pattern area in Example 4 of the present invention. It can be seen from Figure 5 that the spatial resolution can reach 10 ⁇ m, which proves that the method has a high spatial resolution.
  • Figure 6 shows the pattern of each frame in one cycle. It can be found that every point in the pattern is very clear, and the patterns between adjacent frames have obvious differences, indicating that the temporal resolution of the present invention is also high.

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Abstract

A method for visualizing a complex magnetic field, comprising: dispersing monodisperse magnetic particles in a solvent, encapsulating in a PDMS device to obtain a detection device; and placing the detection device on a magnetic field to be tested, and determining the direction and distribution of said magnetic field according to the color and pattern displayed by the device. The monodisperse magnetic particles are magnetic nanoparticles coated with a SiO2 layer on the surface. The magnetic nanoparticles are rod-like, ellipsoidal, spherical cylinder-shaped, or sheet-like. A magnetic material is one or some of Fe3O4 and Ni. According to the method for visualizing a complex magnetic field, by applying the prepared device comprising a magnetic nanorod solution in the vicinity of the complex magnetic field, the direction and distribution of the complex magnetic field can be directly determined by the naked eye according to the color and pattern. The method is simple and convenient, and non-toxic, is low in cost, has high sensitivity and high resolution, and is reusable.

Description

一种可视化复杂磁场的方法A way to visualize complex magnetic fields 技术领域technical field
本发明涉及材料技术领域，尤其是涉及一种可视化复杂磁场的方法。The invention relates to the technical field of materials, in particular to a method for visualizing a complex magnetic field.
背景技术Background technique
地磁场是生命进化的重要条件之一。在自然界中，鸟类、鱼类等动物具有探测地球磁场并将其用作定向、导航的能力。尽管磁场是看不见且不可触摸的，但人类一直没有停下探索、学习和使用磁场的脚步。直到公元前6世纪，人们才意识到磁性的存在。在接下来的几个世纪中，人们逐渐学习如何使用磁场，指南针的出现开启了航海时代，电磁发电技术推动了第二次工业革命。如今，磁性的应用已扩展到各个领域，例如信息、运输、医学、安全、能源、材料、生物学、地质学、海洋学和太空。但是可视化复杂磁场一直是一个难以解决的问题，关于检测磁场的研究一直没有停下。现对比现有检测技术：The geomagnetic field is one of the important conditions for the evolution of life. In nature, animals such as birds and fish have the ability to detect the Earth's magnetic field and use it for orientation and navigation. Although the magnetic field is invisible and untouchable, human beings have not stopped exploring, learning and using the magnetic field. The existence of magnetism was not realized until the 6th century BC. Over the next few centuries, people gradually learned how to use magnetic fields, the advent of the compass ushered in the age of navigation, and the technology of electromagnetic power generation drove the second industrial revolution. Today, the applications of magnetism have expanded to various fields such as information, transportation, medicine, security, energy, materials, biology, geology, oceanography, and space. But visualizing complex magnetic fields has always been a difficult problem to solve, and research on detecting magnetic fields has never stopped. Now compare the existing detection technology:
1)传统检测方法：1) Traditional detection methods:
可以利用指南针指示磁场的方向，利用磁力计来检测磁场的大小。但是对于复杂磁场，目前的检测方法依旧存在一些缺陷。显示磁力线分布的最常见方法是使用铁屑，但是在磁场的作用下，铁屑的聚集导致分辨率的降低。A compass can be used to indicate the direction of the magnetic field, and a magnetometer can be used to detect the magnitude of the magnetic field. However, for complex magnetic fields, the current detection methods still have some defects. The most common way to visualize the distribution of magnetic field lines is to use iron filings, but the accumulation of iron filings under the influence of a magnetic field results in a loss of resolution.
2)利用磁响应型光子晶体检测：2) Using magnetic response photonic crystal detection:
磁响应型光子晶体可以响应外部磁场的刺激，可以将其应用于磁场检测这一领域。1)Zhou报道了利用聚丙烯酸封端的Fe 3O 4胶体纳米晶体簇(CNC)进行磁检测(Scientific Reports,2015,5，17063)；2)Zhang报道了利用椭球型Fe 3O 4@SiO 2胶体纳米溶液可以检测低至4.5高斯的弱磁场(J.Mater.Chem.C,2018,6,5528)。 Magnetically responsive photonic crystals can respond to external magnetic field stimuli and can be used in the field of magnetic field detection. 1) Zhou reported the use of polyacrylic acid-terminated Fe 3 O 4 colloidal nanocrystal clusters (CNC) for magnetic detection (Scientific Reports, 2015, 5, 17063); 2) Zhang reported the use of ellipsoidal Fe 3 O 4 @SiO 2 Colloidal nanosolutions can detect weak magnetic fields down to 4.5 Gauss (J.Mater.Chem.C, 2018, 6, 5528).
上述现有磁响应型光子晶体检测磁场技术的缺点：胶体纳米晶体团簇(CNC)尺寸不均一、易团聚，且该方法只能对磁场强度进行检测(Scientific Reports,2015,5，17063)；商业产品磁显卡只可以观察到黑白两色，无法观察到更细节的地方；且该磁显卡只能观察静止磁场并且无法重复使用。The disadvantages of the above-mentioned existing magnetic-responsive photonic crystal detection technology for magnetic fields: colloidal nanocrystal clusters (CNC) are non-uniform in size and easy to agglomerate, and this method can only detect the magnetic field strength (Scientific Reports, 2015, 5, 17063); The commercial product magnetic graphics card can only observe black and white, and cannot observe more details; and the magnetic graphics card can only observe the static magnetic field and cannot be reused.
发明内容SUMMARY OF THE INVENTION
有鉴于此，本发明要解决的技术问题在于提供一种可视化复杂磁场的方法，本发明的方法可以检测复杂磁场的方向和角度，具有高的时空分辨率。In view of this, the technical problem to be solved by the present invention is to provide a method for visualizing a complex magnetic field. The method of the present invention can detect the direction and angle of the complex magnetic field and has high spatial and temporal resolution.
本发明提供了一种可视化复杂磁场的方法，包括：The present invention provides a method for visualizing a complex magnetic field, comprising:
将磁性单分散的颗粒分散于溶剂中，封装于PDMS器件内，得到检测器件；Disperse the magnetic monodisperse particles in a solvent and encapsulate them in a PDMS device to obtain a detection device;
将所述检测器件置于待测磁场上，可根据呈现的颜色和图案判断磁场的方向和分布；所述磁性单分散的颗粒为表面包覆有SiO 2层的磁性纳米颗粒；所述磁性纳米颗粒的形状为棒状、椭球、球柱体或片；所述磁性材料为Fe 3O 4和Ni中的一种或几种。 The detection device is placed on the magnetic field to be measured, and the direction and distribution of the magnetic field can be judged according to the displayed color and pattern; the magnetic monodisperse particles are magnetic nanoparticles whose surfaces are coated with a SiO 2 layer; the magnetic nanoparticle The shape of the particles is rod, ellipsoid, spherical cylinder or sheet; the magnetic material is one or more of Fe 3 O 4 and Ni.
优选的，所述磁性单分散的颗粒为棒状Fe 3O 4@SiO 2或片状Ni@SiO 2。 Preferably, the magnetic monodisperse particles are rod-shaped Fe 3 O 4 @SiO 2 or flake-shaped Ni@SiO 2 .
优选的，所述磁性单分散的颗粒长轴尺寸为150～180nm，短轴尺寸为30～40nm。Preferably, the long-axis size of the magnetic monodisperse particles is 150-180 nm, and the short-axis size is 30-40 nm.
优选的，所述SiO 2层的厚度为15～80nm。 Preferably, the thickness of the SiO 2 layer is 15-80 nm.
优选的，所述溶剂选自水、乙腈、乙醇或乙二醇中的一种或多种；所述磁性纳米颗粒的质量浓度为10％～24％。Preferably, the solvent is selected from one or more of water, acetonitrile, ethanol or ethylene glycol; the mass concentration of the magnetic nanoparticles is 10% to 24%.
优选的，所述PDMS器件具体为：Preferably, the PDMS device is specifically:
设置有凹槽的PDMS；PDMS provided with grooves;
复合于所述PDMS上的玻璃片。Glass sheet composited on the PDMS.
优选的，所述判断为判断磁场的方向和角度，具体为：Preferably, the judgment is to judge the direction and angle of the magnetic field, specifically:
首先测定光在不同角度磁场下的反射光谱，得到反射光谱的波长或颜色与磁场角度的对应曲线；First, measure the reflection spectrum of light under different angles of magnetic field, and obtain the corresponding curve of the wavelength or color of the reflection spectrum and the angle of the magnetic field;
根据光照在待测磁场下的反射光谱波长或颜色的不同，结合所述曲线，计算出特定波长或颜色下纳米颗粒的角度；According to the difference in the wavelength or color of the reflected spectrum of the light under the magnetic field to be measured, and in combination with the curve, the angle of the nanoparticle under the specific wavelength or color is calculated;
通过上述多个角度连接的闭合曲线，判断出磁场的方向。The direction of the magnetic field is determined by the closed curve connected by the above-mentioned multiple angles.
优选的，所述判断为判断磁场是否有缺陷，具体为：Preferably, the judgment is to judge whether the magnetic field is defective, specifically:
将检测装置置于待测磁场上方，Place the detection device above the magnetic field to be measured,
若装置颜色图案与放置于已知的无缺陷磁场上方所显示出的图案不同，则磁场有缺陷，反之，没有缺陷。If the device color pattern differs from that exhibited by being placed over a known defect-free magnetic field, the magnetic field is defective, otherwise, there is no defect.
优选的，所述判断为检测转动磁场，具体为：Preferably, the judgment is to detect a rotating magnetic field, specifically:
将上述检测器件置于磁力搅拌器上，观察一周期中每一帧图案的变化，从而检测转动磁场。The above detection device is placed on a magnetic stirrer, and the pattern changes of each frame in a cycle are observed, thereby detecting the rotating magnetic field.
优选的，所述磁力搅拌器的转速为1～20r/s。Preferably, the rotational speed of the magnetic stirrer is 1-20 r/s.
与现有技术相比，本发明提供了一种可视化复杂磁场的方法，包括：将磁性单分散的颗粒分散于溶剂中，封装于PDMS器件内，得到检测器件；将所述检测器件置于待测磁场上，可根据呈现的颜色和图案判断磁场的方向和分布；所述磁性单分散的颗粒为表面包覆有SiO 2层的磁性纳米颗粒；所述磁性纳米颗粒的形状为棒状、椭球、球柱体或片；所述磁性材料为Fe 3O 4和Ni中的一种或几种。本发明通过在复杂磁场附近施加所制备的含有磁性纳米棒溶液的器件。通过颜色和图案从而肉眼直接判断出复杂磁场的方向和分布，该方法简便无毒、成本低、灵敏度高、分辨率高、可重复使用。 Compared with the prior art, the present invention provides a method for visualizing a complex magnetic field, comprising: dispersing magnetic monodisperse particles in a solvent, encapsulating them in a PDMS device to obtain a detection device; placing the detection device in a waiting On the magnetic field measurement, the direction and distribution of the magnetic field can be judged according to the color and pattern presented; the magnetic monodisperse particles are magnetic nanoparticles whose surface is coated with a SiO layer ; the shape of the magnetic nanoparticles is rod-like, ellipsoid , spherical cylinder or sheet; the magnetic material is one or more of Fe 3 O 4 and Ni. The present invention applies the prepared device containing the magnetic nanorod solution in the vicinity of a complex magnetic field. The direction and distribution of the complex magnetic field can be directly judged by the naked eye through the color and pattern. The method is simple, non-toxic, low in cost, high in sensitivity, high in resolution and reusable.
附图说明Description of drawings
图1为本发明可视化检测装备示意图；Fig. 1 is the schematic diagram of visual detection equipment of the present invention;
图2为本发明实施例1中的磁场测定结果图；Fig. 2 is the magnetic field measurement result graph in the embodiment 1 of the present invention;
图3为不同磁场下纳米棒的反射光谱；Figure 3 shows the reflection spectra of nanorods under different magnetic fields;
图4为本发明实施例4中检测磁场缺陷的结果图；4 is a result diagram of detecting magnetic field defects in Embodiment 4 of the present invention;
图5为本发明实施例4中放大图案区域得到的显微镜图像；5 is a microscope image obtained by enlarging the pattern area in Example 4 of the present invention;
图6为本发明实施例5中在1r/s的转动磁场上，可视化装置图案变化视频中相邻帧数的图案。FIG. 6 is the pattern of the number of adjacent frames in the video of the pattern change of the visualization device on the rotating magnetic field of 1 r/s in the fifth embodiment of the present invention.
具体实施方式detailed description
本发明提供了一种可视化复杂磁场的方法，本领域技术人员可以借鉴本文内容，适当改进工艺参数实现。特别需要指出的是，所有类似的替换和改动对本领域技术人员来 说是显而易见的，它们都属于本发明保护的范围。本发明的方法及应用已经通过较佳实施例进行了描述，相关人员明显能在不脱离本发明内容、精神和范围内对本文的方法和应用进行改动或适当变更与组合，来实现和应用本发明技术。The present invention provides a method for visualizing a complex magnetic field, and those skilled in the art can learn from the content of this article and appropriately improve the process parameters for realization. It should be particularly pointed out that all similar replacements and modifications are obvious to those skilled in the art, and they all belong to the protection scope of the present invention. The method and application of the present invention have been described through the preferred embodiments, and it is obvious that relevant persons can make changes or appropriate changes and combinations of the methods and applications herein without departing from the content, spirit and scope of the present invention to realize and apply the present invention. Invention technology.
本发明提供了一种可视化复杂磁场的方法，包括：The present invention provides a method for visualizing a complex magnetic field, comprising:
将磁性单分散的颗粒分散于溶剂中，封装于PDMS器件内，得到检测器件；Disperse the magnetic monodisperse particles in a solvent and encapsulate them in a PDMS device to obtain a detection device;
将所述检测器件置于待测磁场上，可根据呈现的颜色和图案判断磁场的方向和分布；所述磁性单分散的颗粒为表面包覆有SiO 2层的磁性纳米颗粒；所述磁性纳米颗粒的形状为棒状、椭球、球柱体或片；所述磁性材料为Fe 3O 4和Ni中的一种或几种。 The detection device is placed on the magnetic field to be measured, and the direction and distribution of the magnetic field can be judged according to the displayed color and pattern; the magnetic monodisperse particles are magnetic nanoparticles whose surfaces are coated with a SiO 2 layer; the magnetic nanoparticle The shape of the particles is rod, ellipsoid, spherical cylinder or sheet; the magnetic material is one or more of Fe 3 O 4 and Ni.
本发明提供的可视化复杂磁场的方法首先将磁性单分散的颗粒溶解于溶剂中。The method of visualizing a complex magnetic field provided by the present invention first dissolves magnetic monodisperse particles in a solvent.
本发明所述磁性单分散的颗粒为表面包覆有SiO 2层的磁性纳米颗粒；所述磁性纳米颗粒的形状为棒状、椭球、球柱体或片；从而使所述磁性物质在磁场作用下具有一定的取向。所述磁性材料为Fe 3O 4和Ni中的一种或几种。 The magnetic monodisperse particles of the present invention are magnetic nanoparticles whose surfaces are coated with a SiO 2 layer; the shape of the magnetic nanoparticles is a rod, an ellipsoid, a spherical cylinder or a sheet; has a certain orientation. The magnetic material is one or more of Fe 3 O 4 and Ni.
按照本发明，所述磁性单分散的颗粒优选为棒状Fe 3O 4@SiO 2或片状Ni@SiO 2。其中，所述磁性单分散的颗粒长轴尺寸为150～180nm，短轴尺寸为30～40nm。 According to the present invention, the magnetic monodisperse particles are preferably rod-shaped Fe 3 O 4 @SiO 2 or flake-shaped Ni@SiO 2 . Wherein, the size of the long axis of the magnetic monodisperse particles is 150-180 nm, and the size of the short axis is 30-40 nm.
所述SiO 2层的厚度为15～80nm。优选为30～65nm。 The thickness of the SiO 2 layer is 15-80 nm. It is preferably 30 to 65 nm.
所述溶剂选自水、乙腈、乙醇或乙二醇中的一种或多种,优选为水；所述磁性物质在水中的分散性较好，将磁性物质分散于水中后，形成高分散性的磁性物质分散液。其中，在所述磁性单分散的颗粒中，所述磁性纳米颗粒的质量浓度为10％～24％；优选为15％～20％。The solvent is selected from one or more of water, acetonitrile, ethanol or ethylene glycol, preferably water; the magnetic substance has good dispersibility in water, and after the magnetic substance is dispersed in water, a high dispersibility is formed. magnetic substance dispersion. Wherein, in the magnetic monodisperse particles, the mass concentration of the magnetic nanoparticles is 10%-24%; preferably, it is 15%-20%.
本发明还提供了一种上述磁性单分散的颗粒的制备方法，包括以下步骤：The present invention also provides a preparation method of the above-mentioned magnetic monodisperse particles, comprising the following steps:
A)在催化剂存在的条件下，向经过修饰的纳米颗粒的分散液中滴加原硅酸四乙酯，进行反应，所述含铁的纳米颗粒为非球形；A) in the presence of a catalyst, dropwise addition of tetraethyl orthosilicate to the dispersion of the modified nanoparticles to carry out the reaction, the iron-containing nanoparticles are non-spherical;
B)将步骤B)得到的反应产物在还原气氛下进行煅烧，得到磁性物质；B) calcining the reaction product obtained in step B) under a reducing atmosphere to obtain a magnetic substance;
C)将所述磁性物质分散于溶剂中，得到胶体晶体溶液。C) Disperse the magnetic substance in a solvent to obtain a colloidal crystal solution.
其中，所述纳米颗粒选自α-Fe 2O 3纳米颗粒或FeOOH纳米颗粒、Ni(OH) 2纳米颗粒。 Wherein, the nanoparticles are selected from α-Fe 2 O 3 nanoparticles, FeOOH nanoparticles, and Ni(OH) 2 nanoparticles.
所述α-Fe 2O 3纳米颗粒按照如下方法进行制备： The α-Fe 2 O 3 nanoparticles are prepared as follows:
将水溶性铁源化合物与磷酸二氢钠溶解在水中，进行加热反应，得到α-Fe 2O 3纳米颗粒。所述水溶性铁源化合物选自六水合氯化铁。 The water-soluble iron source compound and sodium dihydrogen phosphate are dissolved in water, and the heating reaction is carried out to obtain α-Fe 2 O 3 nanoparticles. The water-soluble iron source compound is selected from ferric chloride hexahydrate.
所述加热反应的温度为100℃，所述加热反应的时间为48h。The temperature of the heating reaction was 100° C., and the time of the heating reaction was 48 h.
其中，通过调节反应液的形貌控制剂的种类以及添加量可以控制α-Fe 2O 3纳米颗粒的形貌。 Among them, the morphology of α-Fe 2 O 3 nanoparticles can be controlled by adjusting the type and addition amount of the morphology control agent in the reaction solution.
所述FeOOH纳米颗粒按照如下方法进行制备：The FeOOH nanoparticles are prepared as follows:
将水溶性铁源化合物溶解在水中，调节pH值，进行加热反应，得到FeOOH纳米颗粒。所述水溶性铁源化合物选自六水合氯化铁。The water-soluble iron source compound is dissolved in water, the pH value is adjusted, and the heating reaction is performed to obtain FeOOH nanoparticles. The water-soluble iron source compound is selected from ferric chloride hexahydrate.
所述加热反应的温度为90～100℃，所述加热反应的时间为4～10个小时。The temperature of the heating reaction is 90-100°C, and the time of the heating reaction is 4-10 hours.
其中，通过调节反应液的pH，pH值在1.2～1.94之间，即可得到不同尺寸、不同形状的磁性颗粒，通常反应pH越低，长度越长，直径越小，长径比越大。Among them, by adjusting the pH of the reaction solution, the pH value is between 1.2 and 1.94, and magnetic particles of different sizes and shapes can be obtained. Generally, the lower the reaction pH, the longer the length, the smaller the diameter, and the larger the aspect ratio.
在本发明中，所述含铁的纳米颗粒优选按照文献Nat.Mater.2008,7,242–247和J.Am.Chem.Soc.2013,135,15302–15305水解铁盐的方法制备得到。In the present invention, the iron-containing nanoparticles are preferably prepared according to the methods of hydrolysis of iron salts in documents Nat.Mater.2008, 7, 242-247 and J.Am.Chem.Soc.
所述Ni(OH) 2纳米颗粒按照如下方法进行制备： The Ni(OH) 2 nanoparticles are prepared as follows:
将0.2326g Ni(NO 3) 2·6H 2O溶解于40mL水中并向其中加入10mL PVP(MW360000，0.2g/5mL)搅拌10min后加入242μL NH 3·H 2O搅拌30min。待分散开后置于烘箱中150℃，反应48小时。待反应结束后，取出离心，并重新分散于水中。 Dissolve 0.2326g Ni(NO 3 ) 2 ·6H 2 O in 40 mL of water and add 10 mL of PVP (MW360000, 0.2 g/5 mL) to it, stir for 10 min, and then add 242 μL of NH 3 ·H 2 O and stir for 30 min. After dispersing, it was placed in an oven at 150° C. and reacted for 48 hours. After the reaction is over, take out the centrifuge and re-disperse in water.
所述经过修饰的含铁的纳米颗粒中，用于修饰的修饰剂选自PAA或PVP，所述PAA或PVP修饰含铁的纳米颗粒后，可以使所述含铁的纳米颗粒与原硅酸四乙酯结合。In the modified iron-containing nanoparticles, the modifier used for modification is selected from PAA or PVP. After the iron-containing nanoparticles are modified by the PAA or PVP, the iron-containing nanoparticles can be mixed with orthosilicic acid. Tetraethyl ester binding.
所述经过修饰的含铁的纳米颗粒的制备方法为：The preparation method of the modified iron-containing nanoparticles is:
将含铁的纳米颗粒分散液与含有修饰剂的溶液混合搅拌，得到经过修饰的含铁的纳米颗粒。The iron-containing nanoparticle dispersion liquid and the solution containing the modifier are mixed and stirred to obtain modified iron-containing nanoparticles.
之后，将所述纳米颗粒分散于水后再加入至乙醇中，得到经过修饰的含铁的纳米颗粒的分散液。After that, the nanoparticles are dispersed in water and then added to ethanol to obtain a dispersion liquid of modified iron-containing nanoparticles.
然后，向所述分散液中加入催化剂并混合，混合方式优选为超声混合；Then, the catalyst is added to the dispersion and mixed, and the mixing mode is preferably ultrasonic mixing;
接着，将原硅酸四乙酯分批次的加入至所述分散液中进行反应，其中，所述反应的温度为常温条件，在本发明中，将所述常温定义为25±5℃。Next, tetraethyl orthosilicate is added to the dispersion liquid in batches for reaction, wherein, the temperature of the reaction is a normal temperature condition, and in the present invention, the normal temperature is defined as 25±5°C.
其中，所述磁性纳米颗粒与原硅酸四乙酯的质量体积比为30mg：200μL。Wherein, the mass-volume ratio of the magnetic nanoparticles to tetraethyl orthosilicate is 30 mg: 200 μL.
然后将上述反应的反应产物还原气氛下进行煅烧，得到磁性物质，所述还原气氛选自氢气，当所述含铁的纳米颗粒为FeOOH时，所述煅烧温度为350℃，当所述含铁的纳米颗粒为α-Fe 2O 3时，所述煅烧温度为400℃。当所述纳米颗粒为Ni(OH) 2时，所述煅烧温度为300℃。在该温度条件下，得到的磁性物质的性质显著优于其他温度条件下得到磁性单分散的颗粒。 Then, the reaction product of the above reaction is calcined in a reducing atmosphere to obtain a magnetic substance. The reducing atmosphere is selected from hydrogen. When the iron-containing nanoparticles are FeOOH, the calcination temperature is 350° C. When the nanoparticles are α-Fe 2 O 3 , the calcination temperature is 400 °C. When the nanoparticles are Ni(OH) 2 , the calcination temperature is 300°C. Under this temperature condition, the properties of the obtained magnetic substance are significantly better than the magnetic monodisperse particles obtained under other temperature conditions.
将磁性单分散的颗粒溶解于溶剂中，封装于PDMS器件内，得到检测器件；Dissolving the magnetic monodisperse particles in a solvent and encapsulating them in a PDMS device to obtain a detection device;
本发明所述PDMS器件具体为：设置有凹槽的PDMS；复合于所述PDMS上的玻璃片。The PDMS device of the present invention is specifically: PDMS provided with grooves; and a glass sheet compounded on the PDMS.
本发明对于所述凹槽的形状和规格不进行限定，优选为圆形凹槽，具体规格优选为直径为4cm的圆形凹槽。The present invention does not limit the shape and specification of the groove, preferably a circular groove, and the specific specification is preferably a circular groove with a diameter of 4 cm.
将所述检测器件置于待测磁场上，可根据器件上所呈现的颜色和图案判断磁场的方向和分布。The detection device is placed on the magnetic field to be measured, and the direction and distribution of the magnetic field can be determined according to the colors and patterns presented on the device.
本发明所述复杂磁场可以是各种类型的磁场，包括转动磁场，此外，磁场强度可以低至50高斯。The complex magnetic field described in the present invention can be of various types, including rotating magnetic fields, and in addition, the magnetic field strength can be as low as 50 Gauss.
在本发明其中一部分优选实施方式中，所述判断为判断磁场的方向和角度，具体为：In some preferred embodiments of the present invention, the determination is to determine the direction and angle of the magnetic field, specifically:
首先测定光在不同角度磁场下的反射光谱，得到反射光谱的波长或颜色与磁场角度的对应曲线；First, measure the reflection spectrum of light under different angles of magnetic field, and obtain the corresponding curve of the wavelength or color of the reflection spectrum and the angle of the magnetic field;
根据光照在待测磁场下的反射光谱波长或颜色的不同，结合所述曲线，计算出特定波长或颜色下纳米颗粒的角度；According to the difference in the wavelength or color of the reflected spectrum of the light under the magnetic field to be measured, and in combination with the curve, the angle of the nanoparticle under the specific wavelength or color is calculated;
通过上述多个角度连接的闭合曲线，判断出磁场的方向。The direction of the magnetic field is determined by the closed curve connected by the above-mentioned multiple angles.
本发明所述测定光在不同角度磁场下的反射光谱方法具体为：The specific method for measuring the reflection spectrum of light under different angle magnetic fields according to the present invention is:
光子结构在不同方向磁场下的具有不同的反射谱；通过改变磁场与纳米棒胶体晶体溶液之间的角度来调整磁纳米棒结构颜色。The photonic structure has different reflection spectra under the magnetic field in different directions; the color of the magnetic nanorod structure can be adjusted by changing the angle between the magnetic field and the nanorod colloidal crystal solution.
反射光谱是利用海洋光学DH2000BAL-UV-NIR光谱仪测量得到的。具体表现为将检 测装置置于显微镜载物台上，通过调整磁场方向改变纳米颗粒的取向，从而得到纳米颗粒胶体溶液的颜色，得到相应的反射光谱。The reflectance spectrum was measured using a Ocean Optics DH2000BAL-UV-NIR spectrometer. The specific performance is that the detection device is placed on the microscope stage, and the orientation of the nanoparticles is changed by adjusting the direction of the magnetic field, thereby obtaining the color of the colloidal solution of the nanoparticles, and obtaining the corresponding reflection spectrum.
本发明人发现，溶液中的纳米棒的取向随着磁场方向的改变发生改变，且对磁场强度变化没有响应。因此，可以通过判断纳米棒胶体溶液的结构色判断出磁场的角度。The inventors found that the orientation of the nanorods in the solution changed with the change of the magnetic field direction, and did not respond to the change of the magnetic field intensity. Therefore, the angle of the magnetic field can be judged by judging the structural color of the nanorod colloidal solution.
根据光照在待测磁场下的反射光谱波长或颜色的不同，结合所述曲线，计算出特定波长或颜色下纳米颗粒的角度；According to the difference in the wavelength or color of the reflected spectrum of the light under the magnetic field to be measured, and in combination with the curve, the angle of the nanoparticle under the specific wavelength or color is calculated;
所制备的检测器件置于磁场上方，显示出的图案为磁场上方1mm处的磁场角度图案。根据结构色和磁场角度一一对应的关系，可以由颜色得到特定点的角度。由于磁感应线是闭合的，通过多个角度我们就可以判断出磁场方向的分布。The prepared detection device is placed above the magnetic field, and the displayed pattern is the magnetic field angle pattern at 1 mm above the magnetic field. According to the one-to-one correspondence between structural color and magnetic field angle, the angle of a specific point can be obtained from the color. Since the magnetic induction line is closed, we can judge the distribution of the magnetic field direction through multiple angles.
在本发明其中一部分优选实施方式中，所述判断为判断磁场是否有缺陷，具体为：In some preferred embodiments of the present invention, the judgment is to judge whether the magnetic field is defective, specifically:
将检测装置置于待测磁场上方，Place the detection device above the magnetic field to be measured,
若装置颜色图案与放置于已知的无缺陷磁场上方所显示出的图案不同，则磁场有缺陷；反之，没有缺陷。If the device color pattern differs from that exhibited by being placed over a known defect-free magnetic field, the magnetic field is defective; otherwise, there is no defect.
如中间的灰色区域为一块磁铁。这块磁铁表面看起来是光滑无瑕疵的。对于没有被磁化的区域，其颜色图案是交错的彩色直线。若某一点被磁化，就会显示出一点间隔或者是凸出的点。若是该区域有一条线被磁化，则交错的彩色直线出现断裂并产生一条新的直线。若是某个区域被磁化，该区域的彩色直线都会消失，并产生一大块的图案。因此该方法可以用于检测磁场的缺陷。For example, the gray area in the middle is a magnet. The surface of this magnet appears smooth and flawless. For regions that are not magnetized, the color pattern is staggered colored lines. If a point is magnetized, it will show a little space or bulge. If a line in the area is magnetized, the staggered colored lines break and a new line is created. If an area is magnetized, the colored lines in that area disappear and a large pattern is created. Therefore the method can be used to detect defects in magnetic fields.
利用显微镜观察，本发明人可以发现空间分辨率可以达到10μm，这证明了该方法具有很高的空间分辨率。Using microscope observation, the inventors can find that the spatial resolution can reach 10 μm, which proves that the method has high spatial resolution.
在本发明其中一部分优选实施方式中，所述判断为检测转动磁场，具体为：In some preferred embodiments of the present invention, the determination is to detect a rotating magnetic field, specifically:
将上述检测器件置于磁力搅拌器上，观察一周期中每一帧图案的变化，从而检测转动磁场。The above detection device is placed on a magnetic stirrer, and the pattern changes of each frame in a cycle are observed, thereby detecting the rotating magnetic field.
本发明检测转动磁场，具有高时间分辨率。检测装置置于1r/s的磁力搅拌器上方时，表现出周期性的图案变化。本发明人截取了一周期中每一帧的图案，图案都十分清晰，且相邻帧之间的图案差别很明显，表明其时间分辨率也很高。The invention detects the rotating magnetic field and has high time resolution. When the detection device was placed above the 1r/s magnetic stirrer, it showed periodic pattern changes. The inventors intercepted the pattern of each frame in a cycle, and the pattern is very clear, and the pattern difference between adjacent frames is obvious, indicating that the temporal resolution is also high.
本申请的优点：Advantages of this application:
可以大范围地检测磁场。Magnetic fields can be detected in a wide range.
具有良好的检测极限和高灵敏度。Has good detection limits and high sensitivity.
显示更多的磁场信息。Displays more magnetic field information.
可回收重复利用。Recyclable and reusable.
颗粒为全无机材料，组成元素(铁、硅、氧)均无毒性。The particles are all inorganic materials, and the constituent elements (iron, silicon, oxygen) are non-toxic.
使用方便，易于携带。Easy to use and easy to carry.
该方法具有高时空分辨率。The method has high spatiotemporal resolution.
本发明提供了一种可视化复杂磁场的方法，包括：将磁性单分散的颗粒溶解于溶剂中，封装于PDMS器件内，得到检测器件；将所述检测器件置于待测磁场上，器件内的磁性单分散的颗粒可根据光照呈现的颜色和图案判断磁场的方向和分布；所述磁性单分散的颗粒为表面包覆有SiO 2层的磁性纳米颗粒；所述磁性纳米颗粒的形状为棒状、椭球、球柱体或片；所述磁性材料为Fe 3O 4和Ni中的一种或几种。本发明通过在复杂磁场附近施加所制备的 含有磁性纳米棒溶液的器件，通过颜色和图案从而肉眼直接判断出复杂磁场的方向和分布，该方法简便无毒、成本低、灵敏度高、分辨率高、可重复使用。 The present invention provides a method for visualizing a complex magnetic field, comprising: dissolving magnetic monodisperse particles in a solvent and encapsulating them in a PDMS device to obtain a detection device; placing the detection device on the magnetic field to be measured, The magnetic monodisperse particles can judge the direction and distribution of the magnetic field according to the color and pattern presented by the light; the magnetic monodisperse particles are magnetic nanoparticles whose surface is covered with a SiO 2 layer; the shape of the magnetic nanoparticles is rod-like, Ellipsoid, spherical cylinder or sheet; the magnetic material is one or more of Fe 3 O 4 and Ni. In the present invention, the prepared device containing the magnetic nanorod solution is applied near the complex magnetic field, and the direction and distribution of the complex magnetic field can be directly judged by the naked eye through the color and pattern. The method is simple, non-toxic, low in cost, high in sensitivity and high in resolution. ,reusable.
为了进一步说明本发明，以下结合实施例对本发明提供的一种可视化复杂磁场的方法进行详细描述。In order to further illustrate the present invention, a method for visualizing a complex magnetic field provided by the present invention will be described in detail below with reference to the embodiments.
实施例1Example 1
1.Fe 3O 4@SiO 2纳米棒的合成 1. Synthesis of Fe3O4 @ SiO2 nanorods
将1.623g FeCl 3·6H 2O的溶解于120mL的去离子水中，在磁力搅拌的情况下将该溶液加热到90℃并保持4小时。之后，将该溶液离心洗涤三次，并将离心所得的沉淀，即FeOOH纳米棒重新分散于水中。将含有270mg FeOOH纳米棒的溶液添加到聚丙烯酸钠盐溶液(由64.8mg聚丙烯酸、36mg氢氧化钠、9mL去离子水混合制得)中，搅拌十二小时。离心洗涤后，将修饰过的FeOOH纳米棒重新分散于30mL水中。然后在超声下向该溶液中加入180mL去离子水和9mL 28％的氨水。之后在磁力搅拌下每30分钟加入900μL原硅酸四乙酯(TEOS)，直至TEOS总量达到9mL。继续反应30分钟后，通过离心收集FeOOH@SiO 2纳米棒，并分别用水和乙醇洗涤。之后，将产物放在烘箱中干燥。最后将干燥的FeOOH@SiO 2纳米棒在氢气的氛围中350℃反应4小时得到Fe 3O 4@SiO 2纳米棒。待降至室温后，将其重新溶解于水中并超声分散。未分散的沉淀通过低速离心(200rpm)去除。 1.623 g of FeCl3.6H2O was dissolved in 120 mL of deionized water and the solution was heated to 90°C with magnetic stirring for 4 hours. Afterwards, the solution was centrifuged and washed three times, and the resulting pellet, FeOOH nanorods, was redispersed in water. The solution containing 270 mg of FeOOH nanorods was added to the sodium polyacrylate solution (prepared by mixing 64.8 mg of polyacrylic acid, 36 mg of sodium hydroxide, and 9 mL of deionized water) and stirred for twelve hours. After centrifugation and washing, the modified FeOOH nanorods were redispersed in 30 mL of water. To this solution was then added 180 mL of deionized water and 9 mL of 28% ammonia under sonication. Then 900 μL of tetraethyl orthosilicate (TEOS) was added every 30 minutes under magnetic stirring until the total amount of TEOS reached 9 mL. After continuing the reaction for 30 min, the FeOOH@ SiO2 nanorods were collected by centrifugation and washed with water and ethanol, respectively. After that, the product was dried in an oven. Finally, the dried FeOOH@ SiO2 nanorods were reacted in a hydrogen atmosphere at 350 °C for 4 h to obtain Fe3O4 @ SiO2 nanorods. After cooling to room temperature, it was redissolved in water and dispersed by sonication. Undispersed pellets were removed by low speed centrifugation (200 rpm).
2.可视化检测磁场PDMS器件的制备2. Preparation of PDMS Devices for Visual Detection of Magnetic Fields
将方形玻璃与圆形盖玻片利用紫外固化剂粘合在一起，然后将其放置于培养皿中，并向培养皿中加入混合均匀的8g硅氧烷弹性预聚物和1.5g固化剂。然后培养皿放入60℃的烘箱中2小时使其固化从而得到形状特殊的聚二甲氧基硅烷(PDMS)。将固化的PDMS沿方形玻璃边缘切割后取出，并用针在PDMS薄片凹槽的边缘打两个孔。之后利用等离子体清洗机将PDMS片和玻璃片粘合在一起从而得到所需装备。The square glass and the round coverslip were bonded together with a UV curing agent, and then placed in a petri dish, and 8 g of the silicone elastic prepolymer and 1.5 g of the curing agent were mixed uniformly into the petri dish. The petri dishes were then placed in an oven at 60°C for 2 hours to cure to obtain polydimethoxysilane (PDMS) with a special shape. The cured PDMS was cut along the edge of the square glass and taken out, and two holes were punched at the edge of the PDMS sheet groove with a needle. The PDMS sheet and the glass sheet were then bonded together using a plasma cleaner to obtain the desired equipment.
3.可视化复杂磁场的方法3. Methods to visualize complex magnetic fields
将步骤1所制备的Fe 3O 4@SiO 2纳米棒溶液注入到步骤2所制备的器件中，即为检测磁场的器件(图1所示,图1为本发明可视化检测装备示意图)。将该器件置于复杂磁场上，就可以显示出特殊的颜色图案，从而可以判断出复杂磁场的分布方向。测定结果图2所示。图2为本发明实施例1中的磁场测定结果图；该图为将可视化装置放置于复杂磁场上，可以显示出指示复杂磁场方向的图案。 The Fe 3 O 4 @SiO 2 nanorod solution prepared in step 1 is injected into the device prepared in step 2, which is a device for detecting magnetic field (as shown in FIG. 1 , which is a schematic diagram of the visual detection equipment of the present invention). When the device is placed on a complex magnetic field, a special color pattern can be displayed, so that the distribution direction of the complex magnetic field can be judged. The measurement results are shown in FIG. 2 . FIG. 2 is a diagram of the measurement result of the magnetic field in Example 1 of the present invention; the diagram shows that the visualization device is placed on the complex magnetic field, and a pattern indicating the direction of the complex magnetic field can be displayed.
实施例2Example 2
1.椭球型Fe 3O 4@SiO 2的合成 1. Synthesis of ellipsoid Fe 3 O 4 @SiO 2
将0.85g FeCl 3·6H 2O和3.1mg NaH 2PO 4室温下超声溶解于120mL的去离子水中，然后将其放于100℃烘箱中48小时。在该过程中，溶液逐渐变浑浊，颜色由浅黄色变为深红色。之后，将该溶液离心洗涤三次，并将离心所得的沉淀，即椭球型α-Fe 2O 3重新分散于水中。在超声下向含有50mgα-Fe 2O 3的水溶液(20mL)中加入0.2g PVP。超声1小时后，将其搅拌超2小时，并以转速11000rpm离心30min以去除溶液中多余的PVP。将离心后的沉淀重新分散于6mL的去离子水中，并在超声下向其中加入40mL乙醇和2mL氨水。之后，在磁力搅拌下每隔半小时加入200μLTEOS，直至TEOS总量达到2mL。继续搅拌30分钟后，离心收集椭球型α-Fe 2O 3@SiO 2颗粒。之后，将产物放在烘箱中干燥。最后将干燥的椭球型α-Fe 2O 3@SiO 2颗粒在氢气的氛围中400℃反应2小时得到椭球型Fe 3O 4@SiO 2颗粒。待降至室温后，将其重新溶解于水中并 超声分散。最后将其在100℃水中煮10小时以增强表面电荷。 0.85 g FeCl 3 ·6H 2 O and 3.1 mg NaH 2 PO 4 were sonicated in 120 mL of deionized water at room temperature, and then placed in a 100° C. oven for 48 hours. During this process, the solution gradually became cloudy and the color changed from light yellow to dark red. After that, the solution was washed three times by centrifugation, and the pellet obtained by centrifugation, ie, ellipsoidal α-Fe 2 O 3 , was redispersed in water. To an aqueous solution (20 mL) containing 50 mg of α-Fe 2 O 3 was added 0.2 g of PVP under sonication. After 1 hour of sonication, it was stirred for over 2 hours and centrifuged at 11000 rpm for 30 min to remove excess PVP in solution. The centrifuged pellet was redispersed in 6 mL of deionized water, to which 40 mL of ethanol and 2 mL of ammonia were added under sonication. After that, 200 μL of TEOS was added every half hour under magnetic stirring until the total amount of TEOS reached 2 mL. After continuing to stir for 30 minutes, the ellipsoidal α-Fe 2 O 3 @SiO 2 particles were collected by centrifugation. After that, the product was dried in an oven. Finally, the dried ellipsoidal α-Fe 2 O 3 @SiO 2 particles were reacted in a hydrogen atmosphere at 400 °C for 2 hours to obtain ellipsoidal Fe 3 O 4 @SiO 2 particles. After cooling to room temperature, it was redissolved in water and dispersed by sonication. Finally, it was boiled in 100°C water for 10 hours to enhance the surface charge.
2.可视化复杂磁场。2. Visualize complex magnetic fields.
将椭球型Fe 3O 4@SiO 2溶液注入到器件中，即可显示出特定图案，从而判断出复杂磁场方向和分布。 The ellipsoidal Fe 3 O 4 @SiO 2 solution was injected into the device to display a specific pattern, thereby judging the direction and distribution of the complex magnetic field.
实施例3Example 3
反射光谱是利用海洋光学DH2000BAL-UV-NIR光谱仪测量得到的。具体表现为将可视化检测装置置于显微镜载物台上，通过调整磁场方向改变纳米颗粒的取向，从而改变纳米颗粒胶体溶液的颜色，得到相应的反射光谱。(检测装置见附图1)The reflectance spectrum was measured using a Ocean Optics DH2000BAL-UV-NIR spectrometer. The specific performance is that the visual detection device is placed on the microscope stage, and the orientation of the nanoparticles is changed by adjusting the direction of the magnetic field, thereby changing the color of the colloidal solution of the nanoparticles, and obtaining the corresponding reflection spectrum. (See Figure 1 for the detection device)
图3为不同磁场下纳米棒的反射光谱。(a)为通过改变磁场与纳米棒胶体晶体溶液之间的角度来调整磁纳米棒结构颜色的示意图。(b)为光子结构在不同方向磁场下的反射谱。(c)为光子结构在不同强度磁场下的反射光谱。(在该例子中纳米棒的体积分数为20％，不同的浓度会产生不同范围的反射光。)Figure 3 shows the reflection spectra of nanorods under different magnetic fields. (a) is a schematic diagram of adjusting the color of the magnetic nanorod structure by changing the angle between the magnetic field and the nanorod colloidal crystal solution. (b) is the reflection spectrum of the photonic structure under different magnetic fields. (c) is the reflection spectrum of the photonic structure under different magnetic fields. (The volume fraction of nanorods in this example is 20%, and different concentrations produce different ranges of reflected light.)
通过该图可以发现，溶液中的纳米棒的取向随着磁场方向的改变发生改变，且对磁场强度变化没有响应。因此，可以通过判断纳米棒胶体溶液的结构色判断出磁场的角度。From this figure, it can be found that the orientation of the nanorods in the solution changes with the change of the magnetic field direction, and does not respond to the change of the magnetic field strength. Therefore, the angle of the magnetic field can be judged by judging the structural color of the nanorod colloidal solution.
当磁场角度为0°时，对应的反射光波长为430nm；当磁场角度为90°时，对应的反射光波长为610nm。将这些波长等分，通过计算可以得到某一特定波长下的磁场角度。将所制备的检测器件置于磁场上方，显示出的图案为磁场上方1mm处的磁场角度图案。根据结构色和磁场角度一一对应的关系，可以由颜色得到特定点的角度。由于磁感应线是闭合的，通过多个角度我们就可以判断出磁场方向的分布。When the magnetic field angle is 0°, the corresponding reflected light wavelength is 430 nm; when the magnetic field angle is 90°, the corresponding reflected light wavelength is 610 nm. By dividing these wavelengths equally, the magnetic field angle at a specific wavelength can be obtained by calculation. The prepared detection device was placed above the magnetic field, and the displayed pattern was the magnetic field angle pattern at 1 mm above the magnetic field. According to the one-to-one correspondence between structural color and magnetic field angle, the angle of a specific point can be obtained from the color. Since the magnetic induction line is closed, we can judge the distribution of the magnetic field direction through multiple angles.
实施例4Example 4
通过图案可以判断磁场是否存在缺陷。The pattern can be used to judge whether the magnetic field has defects.
对于附图4为本发明实施例4中检测磁场缺陷的结果图。Fig. 4 is a result diagram of detecting magnetic field defects in Example 4 of the present invention.
由图可以看出中间的灰色区域为一块磁铁。这块磁铁表面看起来是光滑无瑕疵的。对于没有被磁化的区域，其颜色图案是交错的彩色直线(图a)。若某一点被磁化，就会显示出一点间隔或者是凸出的点，如图b,c所示。若是该区域有一条线被磁化，则交错的彩色直线出现断裂并产生一条新的直线(图d)。若是某个区域被磁化，该区域的彩色直线都会消失，并产生一大块的图案(图e,f)。因此该方法可以用于检测磁场的缺陷。It can be seen from the figure that the gray area in the middle is a magnet. The surface of this magnet appears smooth and flawless. For regions that are not magnetized, the color pattern is staggered colored lines (Figure a). If a point is magnetized, it will show a little space or a convex point, as shown in Figures b and c. If a line in this area is magnetized, the interlaced colored lines break and a new line is created (Fig. d). If an area is magnetized, the colored lines in that area disappear and a large pattern is created (Fig. e, f). Therefore the method can be used to detect defects in magnetic fields.
此外，利用显微镜观察图5，图5为本发明实施例4中放大图案区域得到的显微镜图像。由图5可以看出，空间分辨率可以达到10μm，这证明了该方法具有很高的空间分辨率。In addition, FIG. 5 is observed with a microscope, and FIG. 5 is a microscope image obtained by enlarging the pattern area in Example 4 of the present invention. It can be seen from Figure 5 that the spatial resolution can reach 10 μm, which proves that the method has a high spatial resolution.
实施例5Example 5
检测转动磁场，具有高时间分辨率。Detects rotating magnetic fields with high temporal resolution.
当可视化装置放置于1r/s的磁力搅拌器上方时，显示出的图案呈现周期性变化。图6是截取一周期中每一帧的图案，可以发现图案中的每一点都十分清晰，且相邻帧之间图案具有明显的差别，表明本发明的时间分辨率也很高。When the visualization device was placed over a 1 r/s magnetic stirrer, the displayed pattern exhibited periodic changes. Figure 6 shows the pattern of each frame in one cycle. It can be found that every point in the pattern is very clear, and the patterns between adjacent frames have obvious differences, indicating that the temporal resolution of the present invention is also high.
以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本发明的保护范围。The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (10)

  1. 一种可视化复杂磁场的方法，其特征在于，包括：A method of visualizing a complex magnetic field, comprising:
    将磁性单分散的颗粒分散于溶剂中，封装于PDMS器件内，得到检测器件；Disperse the magnetic monodisperse particles in a solvent and encapsulate them in a PDMS device to obtain a detection device;
    将所述检测器件置于待测磁场上，器件内的磁性单分散的颗粒可根据呈现的颜色和图案判断磁场的方向和分布；所述磁性单分散的颗粒为表面包覆有SiO 2层的磁性纳米颗粒；所述磁性纳米颗粒的形状为棒状、椭球、球柱体或片；所述磁性材料为Fe 3O 4和Ni中的一种或几种。 The detection device is placed on the magnetic field to be measured, and the magnetic monodisperse particles in the device can judge the direction and distribution of the magnetic field according to the color and pattern presented ; Magnetic nanoparticles; the shapes of the magnetic nanoparticles are rods, ellipsoids, spherical cylinders or sheets; the magnetic material is one or more of Fe 3 O 4 and Ni.
  2. 根据权利要求1所述的方法，其特征在于，所述磁性单分散的颗粒为棒状Fe 3O 4@SiO 2或片状Ni@SiO 2。 The method according to claim 1, wherein the magnetic monodisperse particles are rod-shaped Fe 3 O 4 @SiO 2 or flake Ni@SiO 2 .
  3. 根据权利要求1所述的方法，其特征在于，所述磁性单分散的颗粒长轴尺寸为150～180nm，短轴尺寸为30～40nm。The method according to claim 1, wherein the magnetic monodisperse particles have a long axis size of 150-180 nm and a short axis size of 30-40 nm.
  4. 根据权利要求1所述的方法，其特征在于，所述SiO 2层的厚度为15～80nm。 The method according to claim 1, wherein the thickness of the SiO 2 layer is 15-80 nm.
  5. 根据权利要求1所述的方法，其特征在于，所述溶剂选自水、乙腈、乙醇或乙二醇中的一种或多种；所述磁性纳米颗粒的质量浓度为10％～24％。The method according to claim 1, wherein the solvent is selected from one or more of water, acetonitrile, ethanol or ethylene glycol; and the mass concentration of the magnetic nanoparticles is 10% to 24%.
  6. 根据权利要求1所述的方法，其特征在于，所述PDMS器件具体为：The method according to claim 1, wherein the PDMS device is specifically:
    设置有凹槽的PDMS；PDMS provided with grooves;
    复合于所述PDMS上的玻璃片。Glass sheet composited on the PDMS.
  7. 根据权利要求1所述的方法，其特征在于，所述判断为判断磁场的方向和角度，具体为：The method according to claim 1, wherein the judgment is to judge the direction and angle of the magnetic field, specifically:
    首先测定在不同角度磁场下的反射光谱，得到反射光谱的波长或颜色与磁场角度的对应曲线；First, measure the reflection spectrum under different angles of magnetic field, and obtain the corresponding curve of the wavelength or color of the reflection spectrum and the angle of the magnetic field;
    根据在待测磁场下的反射光谱波长或颜色的不同，结合所述曲线，计算出特定波长或颜色下纳米颗粒的角度；According to the difference in the wavelength or color of the reflection spectrum under the magnetic field to be measured, combined with the curve, the angle of the nanoparticle under the specific wavelength or color is calculated;
    通过上述多个角度连接的闭合曲线，判断出磁场的方向。The direction of the magnetic field is determined by the closed curve connected by the above-mentioned multiple angles.
  8. 根据权利要求1所述的方法，其特征在于，所述判断为判断磁场是否有缺陷，具体为：The method according to claim 1, wherein the judgment is to judge whether the magnetic field is defective, specifically:
    将检测装置置于待测磁场上方，Place the detection device above the magnetic field to be measured,
    若装置颜色图案与放置于已知的无缺陷磁场上方所显示出的图案不同，则磁场有缺陷，反之，没有缺陷。If the device color pattern differs from that exhibited by being placed over a known defect-free magnetic field, the magnetic field is defective, otherwise, there is no defect.
  9. 根据权利要求1所述的方法，其特征在于，所述判断为检测转动磁场，具体为：The method according to claim 1, wherein the determination is to detect a rotating magnetic field, specifically:
    将上述检测器件置于磁力搅拌器上，观察一周期中每一帧图案的变化，从而检测转动磁场。The above detection device is placed on a magnetic stirrer, and the pattern changes of each frame in a cycle are observed, thereby detecting the rotating magnetic field.
  10. 根据权利要求9所述的方法，其特征在于，所述磁力搅拌器的转速为1～20r/s。The method according to claim 9, wherein the rotational speed of the magnetic stirrer is 1-20 r/s.
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