A method for preparing a supraparticle colloidal probe

Abstract

The present application relates to the technical field of colloidal probe preparation, in particular to a preparation method of super-particle colloidal probe, comprising the following steps: step 1, preparing super-particle colloidal particles; step 2, characterizing the super-particle colloidal particles; step 3, preparing the super-particle colloidal probe. The preparation of the super-particle colloidal probe does not require complex chemical synthesis steps, but only utilizes the self-assembly behavior of colloidal droplets on the super-hydrophobic surface during the evaporation process, so that colloidal particles of different sizes can be conveniently prepared, and the requirements of different scenes can be efficiently met. Therefore, compared with the traditional colloidal probe, the super-particle colloidal probe has a wider application range and a greater cost performance.

Description

Technical Field

[0001] The present invention relates to the technical field of colloid probe preparation, and in particular to a method for preparing a superparticle colloid probe. Background Art

[0002] Microscopes are commonly used to observe the morphology and properties of tiny objects that are difficult to discern with the naked eye. The most commonly used microscope is the optical microscope, but it can only observe microscopic morphologies, and due to the optical diffraction limit, the resolution limit of an optical microscope is 200nm. Therefore, objects smaller than 200nm are difficult to discern with an optical microscope. To improve resolution and characterize more properties of microscopic objects, Gerd Binning, Gerber, and others invented the atomic force microscope (AFM), also known as the scanning force microscope, in 1986. This is a high-resolution scanning probe microscope with a nanoscale resolution of 0.5nm-2nm. The AFM can be used not only to observe the surface micromorphology of a sample, but also to test its mechanical properties.

[0003] The microcantilever of an atomic force microscope is one of its most important components. A microcantilever dimensions typically range from 100µm to 500µm long and 500nm to 5µm thick, with a probe mounted on its tip. The AFM principle is to use the microcantilever to sense and amplify the interaction forces between the probe and the sample, including atomic bonding forces and van der Waals forces. AFM probes can be categorized as sharp-tip probes or colloidal probes. The radius of sharp-tip probes is approximately 10nm, while the radius of colloidal probes is on the micrometer scale. The fabrication of sharp-tip probes requires a highly complex and precise etching process and is primarily used to obtain high-resolution topography and micromechanical properties of the sample. Colloidal probes have been developed to measure particle-to-particle and particle-to-surface interactions. Understanding particle-to-particle and particle-to-surface interactions can help us better understand processes such as particle aggregation, suspension, rheology, deposition, and adhesion. Current colloidal probes primarily consist of a solid colloidal particle. The primary method is to use cantilever movement to bond colloidal particles dispersed on a solid surface. However, this common colloidal probe cannot effectively explore the mechanical interaction processes in aggregated particle systems. Secondly, the size change of existing atomic force probes usually requires a series of etching or chemical synthesis processes, which is time-consuming and complicated.

[0004] Droplet evaporation is a common phenomenon in nature and industry. At room temperature and pressure, when droplets of different volumes containing colloidal particles evaporate on a super-hydrophobic surface, the evaporation mode of the droplets is a constant contact angle mode. The colloidal particles inside the droplets will gather and shrink under the interaction of electrostatic force and van der Waals force, and self-assemble regularly to form spherical super-colloidal particles of different sizes (such as Figure 1 ).

[0005] Based on this principle, this project proposes a method for preparing superparticle colloidal probes. The superparticle colloidal particles in this colloidal probe are formed by the self-assembly of numerous microparticles. Simply by controlling the solid content of the colloidal particle solution and the volume of the droplets, and allowing them to evaporate on a superhydrophobic surface, superparticles can be obtained. This method, which does not rely on complex etching or chemical synthesis, can produce superparticles and easily adjust their size. Compared to traditional colloidal probe preparation methods, this method is more convenient and faster, potentially increasing the popularity of colloidal probes. Summary of the Invention

[0006] (1) Technical issues to be resolved

[0007] In response to the lack of atomic force microscope probes capable of simulating the mechanical interactions of aggregated particle systems and the complex production process of these probes, the present invention aims to: 1) fabricate an atomic force microscope probe capable of measuring the mechanical interactions of aggregated particle systems; and 2) produce colloidal probes of varying sizes simply by evaporating droplets containing colloidal particles of varying volumes, without relying on complex processes such as etching and chemical synthesis.

[0008] (2) Technical solution

[0009] In view of the problems and defects of the prior art, the present invention provides a method for preparing a superparticle colloidal probe, comprising the following steps:

[0010] Step 1, preparing superparticle colloidal particles;

[0011] Step 2, characterizing the superparticle colloidal particles;

[0012] Step 3: Prepare superparticle colloidal probe.

[0013] As a preferred technical solution, step 1 includes:

[0014] a. Prepare a colloidal particle suspension; prepare a colloidal particle suspension with a mass fraction of 0.01%-0.1%, and place it in an ultrasonic cleaning machine for oscillation to make it evenly dispersed;

[0015] b. Preparing a super-hydrophobic surface; preparing a super-hydrophobic surface with a nanostructure, so that its contact angle is greater than 160° and the rolling angle is less than 5°;

[0016] c. Adjust the ambient temperature and humidity; maintain the ambient humidity at 60%-70% and control the ambient temperature at 20℃-25℃;

[0017] d. Extract an appropriate amount of colloidal particle suspension using a micro-droplet extraction device;

[0018] e. Gently place the colloidal particle suspension on the super-hydrophobic surface with nanostructure;

[0019] f particle suspension evaporation; allowing the colloidal particle suspension droplets placed on the super-hydrophobic surface to evaporate in the environment of step c, and obtaining super-particle colloidal particles after the evaporation is completed;

[0020] g. Heat-treating the super-particle colloidal particles. The obtained super-particle colloidal particles are placed in a hot air drying oven and heat-treated at a suitable temperature to eliminate internal stress and improve the stability of the mechanical properties of the super-particle colloidal particles.

[0021] As a preferred technical solution, step 2 includes:

[0022] h morphology observation; using an electron scanning microscope, it can be observed that the superparticle colloid particles obtained by the above method on the super-hydrophobic surface are approximately spherical, and the microparticles are arranged in an orderly manner;

[0023] i Size characterization; observe the size of superparticle colloid particles using a microscope;

[0024] j Mechanical property characterization; using a nanoindenter and selecting a flat diamond indenter to perform mechanical testing on the superparticles.

[0025] As a preferred technical solution, step 3 includes:

[0026] k. Prepare adhesive: Prepare two-component epoxy resin optical adhesive in a 1:1 ratio, use a toothpick to dip an appropriate amount of adhesive onto a clean glass surface, and move this surface to the sample stage of the atomic force microscope;

[0027] Install the cantilever without a probe and adjust the laser spot of the atomic force microscope so that it illuminates the front end of the cantilever;

[0028] Slowly lower the Z axis to a certain position. When the sample surface is roughly visible, stop lowering the Z axis, adjust the sample stage left and right, and use the optical microscope of the atomic force microscope to find the glue on the sample surface and adjust the position of the glue to the bottom of the microcantilever; continue to advance the needle, and when the microcantilever contacts the glue, immediately withdraw the needle; usually, there is a lot of glue on the microcantilever at this time. You can adjust the position of the surface left and right to find a clean area on the sample surface so that the microcantilever can dispense glue twice to reduce the amount of glue;

[0029] n Remove the glass surface stained with glue from the sample stage and place it on the super-hydrophobic surface with super-particle colloidal particles deposited;

[0030] Re-adjust the AFM laser spot so that it illuminates the tip of the cantilever;

[0031] Slowly lower the Z axis to a certain position. When the sample surface is roughly visible, stop lowering the Z axis, adjust the sample stage left and right, and use the optical microscope of the atomic force microscope to find the super-particle colloid particles on the sample surface. Adjust the position of the colloid particles to below the micro-cantilever; continue to advance the needle. When the micro-cantilever contacts the colloid particles, continue to lower the Z axis for a distance to make the glue on the micro-cantilever fully contact the super-particle colloid particles; after quickly withdrawing the needle, the super-particle colloid will adhere to the micro-cantilever;

[0032] qAfter standing at room temperature overnight, a stable superparticle colloidal probe is obtained.

[0033] As a preferred technical solution, before using the super-hydrophobic surface in step b, the surface is gently blown with nitrogen to minimize dust on the super-hydrophobic surface; super-hydrophobic surfaces with micron structures or super-hydrophobic surfaces with dust on the surface will affect subsequent use.

[0034] As a preferred technical solution, it should be noted in step d that the inner diameter of the needle of the micro-droplet extraction device needs to be greater than ten times the radius of the colloidal particles, otherwise clogging is likely to occur.

[0035] As a preferred technical solution, in step e, the colloidal particle suspension needs to be gently placed on the super-hydrophobic surface; if the colloidal particle suspension droplets fall from a height onto the surface, it will affect the wetting state of the droplets, thereby affecting the final result.

[0036] As a preferred technical solution, if the humidity is too low or the ambient temperature is too high in step f, the evaporation process will be accelerated and the colloidal particles inside will not be able to self-assemble in an orderly manner; the evaporation time is positively correlated with the size of the droplets. The larger the volume of the droplets, the longer the evaporation time.

[0037] As a preferred technical solution, the temperature selected for heat treatment in step g will vary depending on the material of the colloidal particles; the lower the melting point / heat deformation temperature of the colloidal particle material, the lower the heat treatment temperature.

[0038] (3) Beneficial effects

[0039] The beneficial effects of the present invention are:

[0040] Atomic force microscope probes can be divided into sharp tip probes and colloidal probes. Existing probe preparation technologies are complex and cannot be used to accurately detect the mechanical interaction process in aggregated particle systems. The present method provides a superparticle colloidal probe and a convenient and economical production and preparation method thereof. Compared with ordinary colloidal probes, this superparticle colloidal probe has a more complex three-dimensional geometric morphology, so it can be used to simulate and study more complex interaction systems, such as the release and absorption process of particles in drug capsules in the human body. Compared with ordinary colloidal probes, superparticle colloidal probes also have a larger specific surface area, so there are more binding sites to graft the required biochemical groups, which can increase the possibility of molecular bond formation, thereby improving the measurement accuracy of interactions between biochemical groups.

[0041] The preparation of this superparticle colloidal probe does not require complex chemical synthesis steps. Instead, it utilizes the self-assembly behavior of colloidal droplets during evaporation on a superhydrophobic surface to conveniently prepare colloidal particles of varying sizes, effectively meeting the needs of diverse scenarios. Therefore, compared to traditional colloidal probes, this superparticle colloidal probe has a wider range of applications and offers a higher cost-effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 This is the process of producing super particle colloidal particles of the present invention;

[0044] Figure 2 It is a super particle under the electron scanning microscope of the present invention;

[0045] Figure 3 It is a super particle colloidal particle located below the micro cantilever under the microscope of the present invention;

[0046] Figure 4 It is a super particle colloidal probe prepared under an electron scanning microscope of the present invention; DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] As attached Figure 1-4 As shown, the purpose of the present invention is achieved through the following technical solutions: a method for preparing a superparticle colloid probe.

[0049] 1) Preparation of superparticle colloidal particles

[0050] (a) Prepare a colloidal particle suspension. Prepare a colloidal particle suspension of a certain mass fraction and place it in an ultrasonic cleaner for oscillation to ensure uniform dispersion. For example, prepare a 0.08% mass fraction suspension of silica colloidal particles or a 0.04% mass fraction suspension of polystyrene colloidal particles, where the particle radius can be between 100 nm and 2 μm. Oscillate the suspension in an ultrasonic cleaner for 10 minutes.

[0051] (b) Prepare a super-hydrophobic surface. Prepare a super-hydrophobic surface with a nanostructure, such that its contact angle is greater than 160° and its sliding angle is less than 5°. Before using the super-hydrophobic surface, gently blow nitrogen gas over the surface to minimize dust. Super-hydrophobic surfaces with microstructures or dust on the surface will affect subsequent use.

[0052] (c) Adjust the ambient temperature and humidity. Maintain the ambient humidity at 60%-70% and the ambient temperature at 20℃-25℃.

[0053] (d) Extracting an appropriate amount of colloidal particle suspension. Use a microdroplet extraction device, such as a syringe, pipette, or inkjet printer, to extract a small volume of colloidal particle suspension. Note that the inner diameter of the needle of the microdroplet extraction device must be greater than ten times the radius of the colloidal particle; otherwise, clogging is likely to occur.

[0054] (e) Placing the colloidal particle suspension on a nanostructured super-hydrophobic surface. Gently place the colloidal particle suspension on the super-hydrophobic surface. If droplets of the colloidal particle suspension fall onto the surface from a height, this will affect the wetting properties of the droplets, thereby affecting the final result.

[0055] (f) Evaporation of the particle suspension. Allow the colloidal particle suspension droplets placed on the super-hydrophobic surface to evaporate in the environment of step (c). Due to the super-hydrophobic nature of the super-hydrophobic surface, the adhesion between the water droplets and the solid surface is very small. Therefore, during the evaporation process, there will be no pinning behavior of the contact line, the contact line of the droplet will gradually decrease, and the droplet can maintain the evaporation of the constant contact angle mode (the solid-liquid contact radius gradually decreases, while the contact angle remains stable). The particles inside the droplet will gather and gather following the retraction of the contact line. At the end of the evaporation, the colloidal particles will self-assemble under the action of electrostatic force and van der Waals force to form strong and orderly arranged super-particle colloidal particles. It should be noted here that if the humidity is too low or the ambient temperature is too high, the evaporation process will accelerate, and the internal colloidal particles will not be able to self-assemble in an orderly manner. The evaporation time is positively correlated with the size of the droplet. The larger the volume of the droplet, the longer it takes to evaporate. Since the solid content of the initial colloidal droplets is less than 0.1%, the evaporation of the colloidal droplets on the super-hydrophobic surface is approximated as the evaporation of pure water droplets on the super-hydrophobic surface, and the evaporation rate is According to formula (1),

[0056]

[0057] Where D is the diffusion coefficient, R c is the contact radius, ρ is the density of the droplet, C s and C ∞ are the concentrations of water vapor at the gas-liquid interface and in the environment, respectively, and f(θ) is a function of the contact angle θ. Therefore,

[0058]

[0059] Where k is a constant. In addition, the droplet volume V is related to the contact radius R c The relationship between them is shown in formula (3),

[0060]

[0061] Since the droplet maintains a constant contact angle for more than 90% of the evaporation process, it can be roughly assumed that the entire evaporation process of the droplet conforms to the constant contact angle model. Combining formula (1-3) and the initial conditions, the time required for evaporation t can be obtained. tot Approximately,

[0062]

[0063] in V0 is the initial volume of the droplet.

[0064] Under the conditions of relative humidity of 60% and ambient temperature of 20℃, the evaporation of colloidal droplet on the surface of θ≈160° has k≈0.063mm2 Therefore, if the initial volume of the droplet is 5 nL, the time required for evaporation is about 3 min.

[0065] (g) Heat-treating the super-particle colloidal particles. The obtained super-particle colloidal particles are placed in a hot air drying oven for heat treatment to eliminate internal stress and improve the stability of the mechanical properties of the super-particle colloidal particles. The temperature selected for heat treatment will vary depending on the material of the colloidal particles. The lower the melting point / heat deformation temperature of the colloidal particle material, the lower the heat treatment temperature. Among them, the heat treatment temperature of polystyrene is 65°C-70°C, and the heat treatment time is 3 hours. The heat treatment temperature of silicon dioxide is 120°C-150°C, and the heat treatment time is 3 hours.

[0066] 2) Characterization of superparticle colloidal particles

[0067] (h) Morphology observation. Using an electron scanning microscope, it can be observed that the super-particle colloidal particles obtained by the above method on the super-hydrophobic surface are approximately spherical, and the microparticles are arranged in an orderly manner, as shown in FIG. Figure 2 shown.

[0068] (i) Size characterization. The size of the superparticle colloid particles was observed using a microscope. The results showed that the radius of the superparticle colloid particles was approximately linearly related to the radius of the evaporating droplet. For example, a silica colloidal particle suspension with a mass fraction of 0.08% and a particle size of 1 μm was used (each mL of the silica colloidal particle suspension contained approximately 7.2×10 8 Silica particles), extract 4 nL of suspension (droplet radius is about 100 μm, containing about 2.9×10 3 After the suspension droplets evaporate on the super-hydrophobic surface, the radius of the resulting super-particle colloid is about r = 10 μm. The apparent volume of the super-particle can be calculated as V = 4.2×10 -15 m 3 (V=4πr 3 / 3), the absolute dense volume of the superparticle is V'=1.5×10 -15 m 3 Therefore, the porosity of the superparticle colloidal particles is P = 64% (P = (V-V') / V × 100%); if 34nL of suspension (droplet radius is 200μm) is extracted, after the suspension droplets evaporate on the superhydrophobic surface, the resulting superparticle radius is about 20μm.

[0069] (j) Characterization of mechanical properties. Use a nanoindenter and select a flat diamond indenter to perform mechanical testing on the superparticles. Fix the superhydrophobic surface with the superparticles attached, position the superparticles, and slowly lower the indenter. When the indenter contacts the sample, press the superparticles downward at a stable loading rate of 10-100uN / s, and pay attention to observe the force-distance curve. When the load reaches 500uN, stop loading and maintain this load for a period of time to keep the system stable, and then unload with the same force. Because this loading process is a plane-sphere system, using the Hertz model, it can be obtained that the Young's modulus of the superparticles is on the order of 40MPa.

[0070] 3) Preparation of superparticle colloidal probes

[0071] (k) Prepare adhesive: Prepare two-component epoxy optical adhesive in a 1:1 ratio. Use a toothpick to apply an appropriate amount of adhesive to a clean glass surface. Move the surface to the sample stage of the atomic force microscope.

[0072] (l) Install a microcantilever without a probe and adjust the laser spot of the atomic force microscope so that it illuminates the front end of the microcantilever.

[0073] (m) Slowly lower the Z axis to a certain position. When the sample surface is roughly visible, stop lowering the Z axis. Adjust the sample stage left and right. Using the AFM optical microscope, locate the adhesive on the sample surface and adjust the adhesive position below the cantilever. Continue advancing the needle. When the cantilever contacts the adhesive, immediately withdraw the needle. Usually, there is a lot of adhesive on the cantilever at this point. Adjust the surface position left and right to find a clean area on the sample surface and dispense the adhesive twice with the cantilever to reduce the amount of adhesive.

[0074] (n) Remove the glass surface stained with glue from the sample stage and place it on the superhydrophobic surface with the superparticle colloidal particles deposited.

[0075] (o) Re-adjust the laser spot of the atomic force microscope so that it illuminates the tip of the microcantilever.

[0076] (p) Slowly lower the Z axis to a certain position. When the sample surface is roughly visible, stop lowering the Z axis, adjust the sample stage left and right, and use the optical microscope of the atomic force microscope to find the super particle colloidal particles on the sample surface. Adjust the position of the colloidal particles to below the micro cantilever ( Figure 3 Continue to advance the needle. Once the cantilever contacts the colloidal particles, continue to lower the Z axis for a certain distance to allow the adhesive on the cantilever to fully contact the superparticle colloidal particles. Quickly withdraw the needle, and the superparticle colloid will adhere to the cantilever.

[0077] (q) After standing at room temperature for one night, a stable superparticle colloidal probe was obtained ( Figure 4 ).

[0078] It should be noted that atomic force microscope probes can be divided into sharp-tip probes and colloidal probes. Existing probe preparation techniques are complex and cannot be used to accurately detect the mechanical interaction processes in aggregated particle systems. However, this method provides a superparticle colloidal probe and a convenient and economical production method. Compared with ordinary colloidal probes, this superparticle colloidal probe has a more complex three-dimensional geometric morphology and can therefore be used to simulate and study more complex interaction systems, such as the release and absorption process of particles in drug capsules in the human body. Compared with ordinary colloidal probes, superparticle colloidal probes also have a larger specific surface area, resulting in more binding sites for grafting desired biochemical groups, which can increase the probability of molecular bond formation and thus improve the measurement accuracy of interactions between biochemical groups. The preparation of this superparticle colloidal probe does not require complex chemical synthesis steps. It only utilizes the self-assembly behavior of colloidal droplets during evaporation on superhydrophobic surfaces to conveniently prepare colloidal particles of different sizes, which can efficiently meet the needs of different scenarios. Therefore, this superparticle colloidal probe has a wider range of applications and a higher cost-effectiveness than traditional colloidal probes.

[0079] The above embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary persons in the art should fall within the scope of protection of the present invention. The technical contents for which protection is sought in the present invention are all recorded in the claims.

Claims

1. A method for preparing a superparticle colloidal probe, characterized in that: The following steps are involved: Step 1, preparing superparticle colloidal particles; (a) preparing a colloidal particle suspension; preparing a colloidal particle suspension having a mass fraction of 0.01% to 0.1%, and placing the suspension in an ultrasonic cleaning machine for oscillation to uniformly disperse the suspension; (b) preparing a super-hydrophobic surface; preparing a super-hydrophobic surface having a nanostructure, wherein the contact angle is greater than 160° and the rolling angle is less than 5°; (c) Adjust the ambient temperature and humidity; maintain the ambient humidity at 60%-70% and control the ambient temperature at 20℃-25℃; (d) extracting an appropriate amount of colloidal particle suspension using a micro-droplet extraction device; (e) The colloidal particle suspension is gently placed on the super-hydrophobic surface with nanostructures; (f) evaporation of the particle suspension; allowing the colloidal particle suspension droplets placed on the super-hydrophobic surface to evaporate in the environment of step (c), and obtaining super-particle colloidal particles after the evaporation is completed; (g) heat-treating the superparticle colloidal particles, placing the obtained superparticle colloidal particles in a hot air drying oven and heat-treating them at a suitable temperature to eliminate internal stress and improve the stability of the mechanical properties of the superparticle colloidal particles; Step 2, characterizing the superparticle colloidal particles; (h) Morphology observation: Scanning electron microscopy revealed that the superparticle colloid particles obtained on the superhydrophobic surface by the above method were approximately spherical in shape, and the microparticles were arranged in an orderly manner. (i) Size characterization: Observe the size of superparticle colloid particles using a microscope; (j) Mechanical property characterization: mechanical testing of the superparticles was performed using a nanoindenter with a flat diamond indenter. Step 3, preparing superparticle colloid probe; (k) Preparing adhesive: Prepare two-component epoxy resin optical adhesive in a 1:1 ratio, use a toothpick to apply an appropriate amount of adhesive to a clean glass surface, and move the surface to the sample stage of the atomic force microscope; (l) Install the cantilever without a probe and adjust the laser spot of the atomic force microscope so that it illuminates the front end of the cantilever; (m) Slowly lower the Z axis to a certain position. When the sample surface is roughly visible, stop lowering the Z axis, adjust the sample stage left and right, and use the optical microscope of the atomic force microscope to find the glue on the sample surface and adjust the position of the glue to the bottom of the microcantilever. Continue to advance the needle. When the microcantilever contacts the glue, immediately withdraw the needle. Usually, there is a lot of glue on the microcantilever at this time. You can adjust the surface position left and right to find a clean area on the sample surface and dispense glue with the microcantilever twice to reduce the amount of glue. (n) Remove the glass surface stained with adhesive from the sample stage and place it on the superhydrophobic surface with superparticle colloidal particles deposited on it; (o) Re-adjust the laser spot of the atomic force microscope so that it illuminates the tip of the microcantilever; (p) Slowly lower the Z axis to a certain position. When the sample surface is roughly visible, stop lowering the Z axis, adjust the sample stage left and right, and use the optical microscope of the atomic force microscope to find the superparticle colloidal particles on the sample surface. Adjust the position of the colloidal particles to below the microcantilever; continue to advance the needle. When the microcantilever contacts the colloidal particles, continue to lower the Z axis for a distance to allow the adhesive on the microcantilever to fully contact the superparticle colloidal particles; after quickly withdrawing the needle, the superparticle colloid will adhere to the microcantilever; (q) After standing at room temperature overnight, a stable superparticle colloidal probe is obtained.

2. The method for preparing a superparticle colloid probe according to claim 1, characterized in that: Before using the super-hydrophobic surface in step (b), the surface is gently blown with nitrogen to reduce dust on the super-hydrophobic surface as much as possible; a super-hydrophobic surface with a micron structure or a super-hydrophobic surface with dust will affect subsequent use.

3. The method for preparing a superparticle colloid probe according to claim 2, characterized in that: In step (d), it should be noted that the inner diameter of the needle of the micro-droplet extraction device needs to be greater than ten times the radius of the colloidal particles, otherwise clogging is likely to occur.

4. The method for preparing a superparticle colloidal probe according to claim 3, characterized in that: In step (e), the colloidal particle suspension needs to be gently placed on the super-hydrophobic surface; if the colloidal particle suspension droplets fall from a height onto the surface, the wetting state of the droplets will be affected, thereby affecting the final result.

5. The method for preparing a superparticle colloid probe according to claim 4, characterized in that: In step (f), if the humidity is too low or the ambient temperature is too high, the evaporation process will be accelerated and the colloidal particles inside will not be able to self-assemble in an orderly manner. The evaporation time is positively correlated with the size of the droplets. The larger the volume of the droplets, the longer the evaporation time.

6. The method for preparing a superparticle colloidal probe according to claim 5, characterized in that: The temperature selected for the heat treatment in step (g) will vary depending on the material of the colloidal particles; the lower the melting point / heat deformation temperature of the colloidal particle material, the lower the heat treatment temperature.

Images