Abstract
Electrostatic charges are ubiquitous in our daily life and production. On the one hand, these invisible electrostatic charges are devastating due to the possibility of electric discharging that may destroy electronic equipment or ignite flammable substances. On the other hand, with sizes several orders of magnitude smaller than that of surface topography, these invisible charges have also emerged as a new dimension in mediating the functions of surfaces, such as energy conversion, liquid transportation, and chemical reactivity. Therefore, the prevention and utilization of electrostatic charges are dependent on the actual situations.In general, there are three typical processes for the electrification of materials, including contact electrification, induction electrification and conduction electrification. This thesis focuses on the prevention of contact electrification and the utilization of induction electrification.
The generation and accumulation of electrostatic charges caused by contact electrification could cause many undesirable consequences. Despite notable progress, the state-of-the-art approaches in the antistatic field suffer from notable limitations such as the need for bulk modification or the delicate control of patterning on surfaces that rely on the neutralization of generated charges. Herein, we reported a general toolbox for the rational design of antistatic coatings by leveraging the elegant choice of chemically heterogeneous components with distinctive electron-donating and electron-accepting functional groups to molecularly engineer the surface potential to achieve an electrostatically homogeneous antistatic surface, which completely prevents charge generation. Such an approach allows for engineering robust antistatic coatings at the molecular level, which imparts rewritable fabrication capability, transparency, and a wide spectrum of choices in substrate materials and morphologies. We believe that our approach provides new insight into the design and fabrication of new antistatic surfaces for a wide range of industrial applications.
In the aspect of the utilization of electrostatic charges, we developed a droplet electrostatic tweezer to manipulate liquid droplets and demonstrated its applications. Tweezers based on optical, acoustic or other external fields have revolutionized the research and application in medicine, life sciences, environmental sciences due to their brilliant abilities in manipulating metal particles and bioparticles. In addition to these solid materials, the manipulation for liquid droplets also plays a vital role in many fields that need size minimization, working efficiency, and reduced labor cost. Despite notable progress, the existing droplet manipulation methods mainly rely on the transformation of substrates or responsiveness of droplets under external force, which suffers from either complex precondition of manipulation systems or unpleased control for droplets in terms of motion behaviors such as distance, velocity, flexibility and so on. Herein, we report a simple but effective droplet electrostatic tweezer (DEST) for remotely and programmatically manipulating droplets under several typical manipulating environments, such as open sloped surface, closed channels, and even under oil. Based on the inherent responsiveness of droplets to the electrostatic field, the DEST manipulates the droplet via a contact-less Coulomb attraction force exerted on droplets, which could flexibly manipulate diverse types of droplets with a wide volume and number range on various substrates, offering a potential platform for a series of applications, such as high-throughput SERS detection with single measuring time less than 20 seconds.
In summary, we investigated the prevention of electrostatic charges caused by contact electrification and the utilization of electrostatic charges from induction electrification. The prevention of contact electrification is achieved by fabricating a chemically heterogeneous but electrostatically homogeneous antistatic surfaces. In terms of the utilization of electrostatic charges, we developed a droplet electrostatic tweezer, based on the electrostatic induction, to remotely and programmatically manipulate the droplets and demonstrated a series of applications.
| Date of Award | 4 Jun 2021 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Zuankai WANG (Supervisor) |
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