A device and method for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers

Abstract

The present invention provides a device and method for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers, belonging to the field of micro-nano particle monitoring. The device includes: an environmental chamber for providing a supersaturated environment; a micro-nano particle generating component for generating a micro-nano particle gas flow and sending the micro-nano particles into the environmental chamber; a first laser generating component and a second laser generating component arranged on opposite sides of the environmental chamber for emitting two laser beams into the environmental chamber; the two laser beams converge in the environmental chamber to generate an optical trap; the micro-nano particles in the environmental chamber are trapped by the optical trap, causing the micro-nano particles to suspend in the environmental chamber; an observation component for observing the particle size change of the micro-nano particles in the environmental chamber; and a rate determination component for determining the heterogeneous condensation rate of single particles according to the particle size change of the micro-nano particles in the environmental chamber. It avoids the influence of the bottom of the environmental chamber or the collection plate on the particle condensation rate and improves the measurement accuracy of the heterogeneous condensation rate of micro-nano single particles.

Description

Technical Field

[0001] The present invention relates to the field of micro-nano particle monitoring, and in particular to a device and method for measuring the heterogeneous condensation rate of micro-nano single particles based on an optical tweezer. Background Art

[0002] Heterogeneous condensation of particles widely exists in nature and industrial life. For example: (1) In the natural rainfall process, water vapor in the cloud condenses on the particle surface to form droplets, and when the droplets condense to a certain scale, they fall to form rainfall; (2) In a particle condensation counter, since the particle size of nano-particles is too small to be detected by optical means, heterogeneous condensation technology is used to first condense saturated vapor on the particle surface to make its particle size larger and then be detected; (3) In industrial dust removal, due to the too small particle size of micro-nano particles, the dust removal efficiency is low, and heterogeneous condensation technology is used to condense vapor on the micro-nano particle surface to make its particle size larger and then improve the removal efficiency. Due to the wide application of particle heterogeneous condensation in reality, it is very meaningful to study the heterogeneous condensation rate of particles.

[0003] Whether in the natural environment or in the real industry, the heterogeneous condensation of particles occurs in a suspended state without any contact with the wall surface. In addition, the theoretical model of particle heterogeneous condensation is also based on suspended particles. The water vapor around the particles diffuses towards the particle surface under the action of the vapor pressure, and the water vapor close to the particle surface condenses on the particle surface.

[0004] The current method for measuring the heterogeneous condensation rate of particles is to place the particles at the bottom of the environmental chamber or on the collection plate (as Figure 1 shown), make the particles condense and grow in the supersaturated environment in the environmental chamber, and use a microscope to observe the condensation rate of the particles attached to the collection plate. At this time, the particles are in direct contact with the bottom of the environmental chamber or the collection plate. However, the particles attached to the bottom of the environmental chamber or the collection plate are in a different state from the suspended particles, and the bottom of the environmental chamber or the collection plate in contact with the particles has a serious impact on the heterogeneous condensation rate of the particles. Therefore, the accuracy of the heterogeneous condensation rate of particles measured by the traditional method is low and cannot be used for the study of the heterogeneous condensation rate of particles in the real environment and the theoretical model. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for measuring the heterogeneous condensation rate of micro-nano single particles based on an optical tweezer, which can improve the accuracy of measuring the heterogeneous condensation rate of micro-nano single particles.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] A device for measuring the heterogeneous condensation rate of micro-nano single particles based on an optical tweezer, comprising:

[0008] An environmental chamber for providing a supersaturated environment;

[0009] A micro-nano particle generating component, which is communicated with the environmental chamber, is used for generating a micro-nano particle airflow and sending the micro-nano particles in the micro-nano particle airflow into the environmental chamber;

[0010] A first laser generating component, which is arranged on one side of the environmental chamber, is used for emitting a first laser beam into the environmental chamber;

[0011] A second laser generating component, which is arranged on the side of the environmental chamber opposite to the first laser generating component, is used for emitting a second laser beam into the environmental chamber; the first laser beam and the second laser beam converge in the environmental chamber to generate an optical trap; the micro-nano particles in the environmental chamber are captured by the optical trap, so that the micro-nano particles are suspended in the environmental chamber;

[0012] An observation component, which is used for observing the particle size change of the micro-nano particles in the environmental chamber;

[0013] A rate determination component, which is connected to the observation component, is used for determining the heterogeneous condensation rate of single particles according to the particle size change of the micro-nano particles in the environmental chamber.

[0014] Optionally, the device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers further includes:

[0015] A temperature-controlled water bath, which is communicated with the environmental chamber, is used for controlling the temperature in the environmental chamber.

[0016] Optionally, the device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers further includes:

[0017] A humidity controller, which is connected to the environmental chamber, is used for controlling the humidity in the environmental chamber.

[0018] Optionally, the micro-nano particle generating component includes:

[0019] An aerosol generator, which is used for generating a micro-nano particle airflow;

[0020] A pipeline, which is respectively communicated with the aerosol generator and the environmental chamber, is used for sending the micro-nano particle airflow into the environmental chamber.

[0021] Optionally, the first laser generating component includes:

[0022] A first laser, which is arranged on one side of the environmental chamber, is used for generating a first laser beam;

[0023] A first convex lens, which is arranged between the first laser and the environmental chamber and is located on the optical path of the first laser beam, is used for converging the first laser beam to the central position in the environmental chamber.

[0024] Optionally, the optical tweezer-based micro-nano single-particle heterogeneous condensation rate measurement device further includes:

[0025] A first laser controller, which is respectively connected to the first laser and the condensation rate determination component, and is used to adjust the power of the first laser according to the change in the particle size of the micro-nano particles.

[0026] Optionally, the second laser generation component includes:

[0027] A second laser, which is arranged on the side of the environmental chamber opposite to the first laser generation component, and is used to generate a second laser beam;

[0028] A second convex lens, which is arranged between the second laser and the environmental chamber and is located on the optical path of the second laser beam, and is used to converge the second laser beam to the central position inside the environmental chamber.

[0029] Optionally, the optical tweezer-based micro-nano single-particle heterogeneous condensation rate measurement device further includes:

[0030] A second laser controller, which is respectively connected to the second laser and the condensation rate determination component, and is used to adjust the power of the second laser according to the change in the particle size of the micro-nano particles.

[0031] Optionally, the observation component is an optical microscope.

[0032] To achieve the above object, the present invention also provides the following solution:

[0033] An optical tweezer-based micro-nano single-particle heterogeneous condensation rate measurement method, including:

[0034] Form a supersaturated environment inside the environmental chamber;

[0035] Generate a micro-nano particle gas flow through a micro-nano particle generation component, and send the micro-nano particle gas flow into the environmental chamber;

[0036] Generate two laser beams on opposite sides of the environmental chamber through the first laser generation component and the second laser generation component, and the two laser beams converge inside the environmental chamber to form an optical trap; the micro-nano particles are trapped by the optical trap, so that the micro-nano particles are suspended inside the environmental chamber;

[0037] Real-time observe the change in the particle size of the micro-nano particles inside the environmental chamber through an observation component;

[0038] Determine the heterogeneous condensation rate of a single particle according to the change in the particle size through a rate determination component.

[0039] According to the specific embodiments provided by the present invention, the following technical effects are disclosed: Two laser beams are generated on opposite sides of the environmental chamber by the first laser generating component and the second laser generating component. The two laser beams converge inside the environmental chamber. Using the optical tweezer technology, the two laser beams are focused to form an optical trap. When the micro-nano particles pass near the optical trap, they are trapped at the optical trap under the action of the optical pressure, thereby realizing the suspension of the particles in the environmental chamber with a certain temperature and humidity. Then, the change in the particle size of the micro-nano particles in the environmental chamber is observed, and further the condensation rate of the suspended particles in the supersaturated water vapor environment is obtained, avoiding the influence of the substrate of the traditional method on the particle condensation rate and improving the accuracy of measuring the heterogeneous condensation rate of micro-nano single particles. Brief Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 Schematic diagram of an existing single-particle heterogeneous condensation rate measuring device;

[0042] Figure 2 Schematic diagram of the structure of the micro-nano single-particle heterogeneous condensation rate measuring device based on optical tweezers of the present invention;

[0043] Figure 3 Flowchart of the micro-nano single-particle heterogeneous condensation rate measuring method based on optical tweezers of the present invention.

[0044] Symbol Explanation:

[0045] Environmental chamber - 1, Micro-nano particle generating component - 2, Aerosol generator - 201, Pipeline - 202, First laser generating component - 3, First laser - 301, First convex lens - 302, Second laser generating component - 4, Second laser - 401, Second convex lens - 402, First laser controller - 5, Second laser controller - 6, Optical microscope - 7, Temperature-controlled water bath - 8, Humidity controller - 9, Rate determination component - 10, Micro-nano particle - 11. Detailed Embodiments

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

[0047] The object of the present invention is to provide a device and method for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers. By adopting the optical tweezer technology, two laser beams are focused to form an optical trap, and the micro-nano particles are trapped at the optical trap, so as to realize the suspension of the particles in the environmental chamber, avoid the influence of the substrate on the particle condensation rate, and improve the accuracy of measuring the heterogeneous condensation rate of micro-nano single particles.

[0048] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] As Figure 2 shown, the device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers of the present invention includes: an environmental chamber 1, a micro-nano particle generating component 2, a first laser generating component 3, a second laser generating component 4, an observation component and a rate determination component 10.

[0050] Among them, the environmental chamber 1 is used to provide a supersaturated environment.

[0051] The micro-nano particle generating component 2 is communicated with the environmental chamber 1. The micro-nano particle generating component 2 is used to generate a micro-nano particle airflow and send the micro-nano particles in the micro-nano particle airflow into the environmental chamber 1.

[0052] In this embodiment, the micro-nano particle generating component 2 includes: an aerosol generator 201 and a pipeline 202. The aerosol generator 201 is used to generate a micro-nano particle airflow. The pipeline 202 is respectively communicated with the aerosol generator 201 and the environmental chamber 1, and the pipeline 202 is used to send the micro-nano particle airflow into the environmental chamber 1.

[0053] Specifically, the aerosol generator 201 generates an airflow carrying aerosols with specific components and specific particle sizes. The pipeline is a pipeline that prevents particle adhesion.

[0054] The first laser generating component 3 is arranged on one side of the environmental chamber 1, and the first laser generating component 3 is used to emit a first laser beam into the environmental chamber 1.

[0055] Specifically, the first laser generating component 3 includes: a first laser 301 and a first convex lens 302. The first laser 301 is arranged on one side of the environmental chamber 1, and the first laser 301 is used to generate a first laser beam. The first convex lens 302 is arranged between the first laser 301 and the environmental chamber 1 and is located on the optical path of the first laser beam. The first convex lens 302 is used to converge the first laser beam to the central position in the environmental chamber 1.

[0056] The second laser generating component 4 is arranged on the side of the environmental chamber 1 opposite to the first laser generating component 3. The second laser generating component 4 is used to emit a second laser beam into the environmental chamber 1. The first laser beam and the second laser beam converge in the environmental chamber 1 to generate an optical trap. The micro-nano particles 11 in the environmental chamber 1 are captured by the optical trap, causing the micro-nano particles 11 to be suspended in the environmental chamber 1.

[0057] Specifically, the second laser generating component 4 includes: a second laser 401 and a second convex lens 402. The second laser 401 is arranged on the side of the environmental chamber 1 opposite to the first laser 301. The second laser 401 is used to generate a second laser beam. The second convex lens 402 is arranged between the second laser 401 and the environmental chamber 1 and is located on the optical path of the second laser beam. The second convex lens 402 is used to converge the second laser beam to the central position in the environmental chamber 1.

[0058] In this embodiment, the two sides of the environmental chamber 1 are transparent walls, enabling the lasers on both sides to enter the environmental chamber 1.

[0059] The observation component is used to observe the particle size change of the micro-nano particles 11 in the environmental chamber 1. In this embodiment, the observation component is an optical microscope 7.

[0060] The rate determination component 10 is connected to the observation component. The rate determination component 10 is used to determine the heterogeneous condensation rate of single particles according to the particle size change of the micro-nano particles 11 in the environmental chamber 1.

[0061] In addition, the optical tweezer-based micro-nano single particle heterogeneous condensation rate measurement device further includes a first laser controller 5 and a second laser controller 6. The first laser controller 5 is respectively connected to the first laser 301 and the rate determination component 10. The first laser controller 5 is used to adjust the power of the first laser 301 according to the particle size change of the micro-nano particles. The second laser controller 6 is respectively connected to the second laser 401 and the rate determination component 10. The second laser controller 6 is used to adjust the power of the second laser 401 according to the particle size change of the micro-nano particles.

[0062] Furthermore, the optical tweezer-based micro-nano single particle heterogeneous condensation rate measurement device of the present invention further includes a temperature-controlled water bath 8 and a humidity controller 9. The temperature-controlled water bath 8 and the humidity controller 9 are both connected to the environmental chamber 1. The temperature-controlled water bath 8 is used to control the temperature in the environmental chamber 1. The humidity controller 9 is used to control the humidity in the environmental chamber 1.

[0063] The present invention adopts optical tweezers technology to make two laser beams converge in the environmental chamber 1 to generate an optical trap with a certain intensity. When a micro-nano scale single particle passes near the optical trap, it is trapped at the optical trap under the action of optical pressure, thereby realizing the suspension of the particle in the environmental chamber 1 with a certain temperature and humidity. Then, a microscope is used to observe the change in the particle size of the suspended particle, and further obtain the condensation rate of the suspended particle in a supersaturated water vapor environment, avoiding the influence of the substrate on the particle condensation rate in the traditional method. The measured particle state is consistent with the actual industry and theoretical model, meeting the requirements for the study of heterogeneous condensation of particles.

[0064] To better understand the solution of the present invention, the following further describes it in combination with the measurement method of the heterogeneous condensation rate of micro-nano single particles.

[0065] As Figure 3 shown, the measurement method of the heterogeneous condensation rate of micro-nano single particles based on optical tweezers of the present invention includes:

[0066] S1: Form a supersaturated environment in the environmental chamber 1. Specifically, under the action of the high-precision constant temperature water bath 8 and the humidity controller 9, a supersaturated environment with a certain temperature and a certain humidity is generated in the environmental chamber 1.

[0067] S2: Generate a micro-nano particle airflow through the micro-nano particle generating component 2 and send the micro-nano particle airflow into the environmental chamber 1. In this embodiment, an airflow carrying micro-nano particles with specific components and specific particle sizes is generated by the aerosol generator 201, and the micro-nano particles are sent into the environmental chamber 1.

[0068] S3: Generate two laser beams on the opposite sides of the environmental chamber 1 through the first laser generating component 3 and the second laser generating component 4, and the two laser beams converge in the environmental chamber 1 to form an optical trap. The micro-nano particle 11 is trapped by the optical trap, so that the micro-nano particle 11 is suspended in the environmental chamber 1.

[0069] Specifically, two laser beams with specific wavelengths and specific powers are generated by the lasers arranged on the left and right sides of the environmental chamber 1 under the action of the laser controller. The laser passes through the convex lens and converges at the center of the environmental chamber 1, and an optical trap with a certain intensity is generated at the center position of the environmental chamber 1. When the micro-nano particles generated by the aerosol generator 201 pass through the optical trap in the environmental chamber 1, they are captured by the optical trap under the action of optical pressure.

[0070] Among them, the laser wavelength is selected according to the particle components and the condensation working fluid components, and the absorption bands of the particles and the condensation working fluid should be avoided to prevent the laser from being absorbed by the particles and generating heat.

[0071] S4: Observe the change in the particle size of the micro-nano particle 11 in the environmental chamber 1 in real time through the observation component. In this embodiment, a microscope is used to observe the particle size of the particles in real time.

[0072] S5: The rate determination component 10 determines the heterogeneous condensation rate of a single particle according to the particle size variation. Specifically, the heterogeneous condensation rate of a single particle can be determined according to the particle size of the particles at each moment and the observed time interval.

[0073] Since the mass of the micro-nano particles continuously increases during the condensation growth process, the method for measuring the heterogeneous condensation rate of a single micro-nano particle based on an optical tweezer in this invention further includes:

[0074] S6: Adjust the powers of the two lasers through the laser controller to continuously and stably suspend the single particle at the central position of the environmental chamber 1.

[0075] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts among the various embodiments, reference can be made to each other.

[0076] Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers, characterized in that, The device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers includes: An environmental chamber for providing a supersaturated environment; A micro-nano particle generating component, which is connected to the environmental chamber and is used for generating a micro-nano particle gas flow and sending the micro-nano particles in the micro-nano particle gas flow into the environmental chamber; A first laser generating component, which is arranged on one side of the environmental chamber and is used for emitting a first laser beam into the environmental chamber; the first laser generating component includes: a first laser, which is arranged on one side of the environmental chamber and is used for generating a first laser beam; a first convex lens, which is arranged between the first laser and the environmental chamber and is located on the optical path of the first laser beam and is used for converging the first laser beam to the central position in the environmental chamber; A second laser generating component, which is arranged on the side of the environmental chamber opposite to the first laser generating component and is used for emitting a second laser beam into the environmental chamber; the second laser generating component includes: a second laser, which is arranged on the side of the environmental chamber opposite to the first laser generating component and is used for generating a second laser beam; a second convex lens, which is arranged between the second laser and the environmental chamber and is located on the optical path of the second laser beam and is used for converging the second laser beam to the central position in the environmental chamber; the first laser beam and the second laser beam converge in the environmental chamber to generate an optical trap; the micro-nano particles in the environmental chamber are captured by the optical trap, so that the micro-nano particles are suspended in the environmental chamber; An observation component for observing the particle size change of the micro-nano particles in the environmental chamber; A rate determination component, which is connected to the observation component and is used for determining the heterogeneous condensation rate of single particles according to the particle size change of the micro-nano particles in the environmental chamber; A first laser controller, which is respectively connected to the first laser and the rate determination component and is used for adjusting the power of the first laser according to the particle size change of the micro-nano particles; A second laser controller, which is respectively connected to the second laser and the rate determination component and is used for adjusting the power of the second laser according to the particle size change of the micro-nano particles; Adjust the powers of the two lasers through the laser controller to continuously and stably suspend a single particle at the central position of the environmental chamber.

2. The micro-nano single-particle heterogeneous condensation rate measurement device based on an optical tweezer according to claim 1, wherein The device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers further includes: A temperature-controlled water bath, which is connected to the environmental chamber and is used for controlling the temperature in the environmental chamber.

3. The micro-nano single-particle heterogeneous condensation rate measurement device based on an optical tweezer according to claim 1, wherein The device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers further includes: A humidity controller, which is connected to the environmental chamber and is used for controlling the humidity in the environmental chamber.

4. The micro-nano single-particle heterogeneous condensation rate measuring device based on an optical tweezer according to claim 1, characterized in that, The micro-nano particle generating component includes: An aerosol generator for generating a micro-nano particle gas flow; A pipeline, which is respectively connected to the aerosol generator and the environmental chamber and is used for sending the micro-nano particle gas flow into the environmental chamber.

5. The micro-nano single-particle heterogeneous condensation rate measuring device based on an optical tweezer according to claim 1, wherein, The observation component is an optical microscope.

6. A method for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers, which uses the device for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers according to any one of claims 1-5, characterized in that, The method for measuring the heterogeneous condensation rate of micro-nano single particles based on optical tweezers includes: Form a supersaturated environment in the environmental chamber; Generate a micro-nano particle gas flow through the micro-nano particle generating component and send the micro-nano particle gas flow into the environmental chamber; Two laser beams are generated on opposite sides of the environmental chamber by a first laser generation component and a second laser generation component, and the two laser beams converge within the environmental chamber to form an optical trap; the micro-nano particles are trapped by the optical trap, causing the micro-nano particles to be suspended within the environmental chamber; The particle size change of the micro-nano particles within the environmental chamber is observed in real time by an observation component; A single-particle heterogeneous condensation rate is determined by a rate determination component according to the particle size change; The powers of the two lasers are adjusted by a laser controller to continuously and stably suspend a single particle at the central position of the environmental chamber.

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