A method for preparing negative acoustic levitation droplets based on ultraviolet light irradiation

Abstract

The application provides a method for preparing negative electric acoustic levitation droplets based on ultraviolet irradiation, which comprises the following steps: (1) using an ultrasonic transducer with a fixed frequency to form an acoustic field to ensure that the droplets can be stably suspended; (2) using a micro-injection pump to precisely control the generation of droplets with a volume of 20 muL, and making the droplets flow out of the needle and be stably suspended in the acoustic field range; (3) placing a square metal sheet with a side length of 5 mm in the experimental area, and preparing an ultraviolet lamp with a wavelength of 254 nm; (4) turning on the ultraviolet lamp to irradiate the metal sheet, and the metal sheet emits an electron jet in the direction of the droplets, and the acoustic levitation droplets are negatively charged after capturing the electrons. The method does not need a high-voltage electric field or liquid-solid contact, avoids the problem of droplet contamination, and realizes the precise regulation and control of the non-contact charging of the droplets, and has a wide application prospect in the fields of life science and material science.

Description

Technical fields:

[0001] This invention belongs to the field of droplet charging and designs a method for preparing negatively charged acoustically suspended droplets based on ultraviolet light irradiation. Background technology:

[0002] In recent years, droplet charging technology, as an emerging technology, has been widely applied in fields such as life sciences and materials science. Currently, traditional droplet charging methods mainly include high-voltage electric field charging and liquid-solid contact charging. However, high-voltage electric field charging is difficult to stably prepare charged droplets and is costly; liquid-solid contact charging is difficult to effectively generate negatively charged droplets, and the charge is difficult to control precisely. In addition, these methods inevitably introduce impurities during the charging process, leading to droplet contamination, which further limits their application.

[0003] Therefore, we designed a method for preparing negatively charged acoustically suspended droplets based on ultraviolet light irradiation. This method not only enables the preparation of negatively charged droplets under non-contact conditions but also allows for precise control of the droplet's charge. Summary of the Invention:

[0004] To achieve non-contact preparation of negatively charged droplets and precise control of their charge, this invention provides a method for preparing negatively charged acoustically suspended droplets based on ultraviolet light irradiation. This method involves irradiating a metal with ultraviolet light, causing it to generate an electron jet. The droplets, in an acoustically suspended state, capture electrons from the jet, thereby acquiring a stable negative charge. Compared to traditional methods, this invention eliminates the need for a high-voltage electric field or liquid-solid contact, avoiding droplet contamination problems, and achieves precise, non-contact control of the droplet's charge, showing broad application prospects in life sciences and materials science.

[0005] The technical solution of this invention is as follows:

[0006] A method for preparing negatively charged acoustically suspended droplets based on ultraviolet light irradiation includes the following steps:

[0007] (1) A sound field is formed by using an ultrasonic transducer with a fixed frequency to ensure that the droplets can be stably suspended;

[0008] (2) Using a micro-injection pump for precise control, a droplet with a volume of 20 μL is generated and flows out from the needle, suspending stably within the sound field range;

[0009] (3) Place a square metal sheet with a side length of 5mm in the experimental area and prepare an ultraviolet lamp with a wavelength of 254nm;

[0010] (4) Turn on the ultraviolet lamp to irradiate the metal sheet. The metal sheet emits an electron jet towards the droplet. The acoustically suspended droplet captures the electrons and becomes negatively charged.

[0011] Furthermore, by adjusting the duration of ultraviolet light irradiation on the metal sheet, the charge of the negatively charged acoustically suspended droplets can be precisely controlled.

[0012] Furthermore, the device used to measure the charge of the droplet is a Faraday cylinder.

[0013] The beneficial effects of this invention are as follows:

[0014] This invention effectively controls the charge of droplets by adjusting the irradiation time of an ultraviolet lamp. It provides a low-cost, non-contact method for preparing negatively charged droplets that eliminates the need for a high-voltage power supply, while simultaneously achieving precise control over the charge of the droplets. Attached image description:

[0015] Figure 1 A schematic diagram of the sound field formed by the ultrasonic transducer of the present invention;

[0016] Figure 2 A schematic diagram illustrating the stable suspension of droplets within the acoustic field range of this invention;

[0017] Figure 3 A schematic diagram showing the relative positions of the ultraviolet lamp, zinc sheet, and droplet in this invention;

[0018] Figure 4 A schematic diagram illustrating the preparation of negatively charged acoustic suspension droplets according to this invention;

[0019] Figure 5 The relationship between ultraviolet irradiation duration and droplet charge in this invention; Detailed implementation method:

[0020] The specific embodiments of the present invention are described below, and the invention will be further illustrated in conjunction with the examples and accompanying drawings to ensure that those skilled in the art can gain a thorough understanding.

[0021] Example 1

[0022] (1) A fixed-frequency ultrasonic transducer is used to form an acoustic field to ensure that the droplets can be stably suspended (see Figure 1 );

[0023] (2) Using a micro-injection pump for precise control, a 20 μL droplet is generated and flows out from the needle, suspending stably within the sound field (see...). Figure 2 );

[0024] (3) Prepare a 254nm ultraviolet lamp, ensuring that the ultraviolet lamp is 10cm away from the droplet. Place a square zinc plate with a side length of 5mm in the experimental area, 4cm away from the ultraviolet lamp (see...). Figure 3 );

[0025] (4) Turn on the ultraviolet lamp to irradiate the metal sheet. The metal sheet emits an electron jet towards the droplet. The acoustically suspended droplet captures the electrons and becomes negatively charged (see...). Figure 4 );

[0026] (5) Charged droplets generated under different ultraviolet light irradiation durations were placed in Faraday cells, and the charge of the droplets was measured. The charge of the droplets was positively correlated with the irradiation duration (see [reference]). Figure 5 );

[0027] Matters not covered in this invention are common knowledge.

Claims

1. A method for preparing negatively charged acoustically suspended droplets based on ultraviolet light irradiation, characterized in that, Includes the following steps: (1) A sound field is formed by using an ultrasonic transducer with a fixed frequency to ensure that the droplets can be stably suspended; (2) Using a micro-injection pump for precise control, a droplet with a volume of 20 μL is generated and flows out from the needle, suspending stably within the sound field range; (3) Place a square metal sheet with a side length of 5mm in the experimental area and prepare an ultraviolet lamp with a wavelength of 254nm; (4) Turn on the ultraviolet lamp to irradiate the metal sheet. The metal sheet emits an electron jet towards the droplet. The acoustically suspended droplet captures the electrons and becomes negatively charged.

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