Wetting refers to the behaviour of a liquid when deposited on a surface. Many practical applications depend on our understanding of wetting. These include dropwise condensation, synthesis of advanced materials, biological assays, etc. A number of studies have been devoted to adhesion forces, for example, between liquid droplets and solid surfaces with specialised wettability.
Evidence suggests that droplet wetting behaviours are related to its interfacial forces and dynamics but this is not fully understood. For example, the interfacial properties and stabilities due to droplet adhesion/friction (mobility) depend on droplet size, motion (rolling or sliding), state (attached or detached), etc. An ability to control adhesion at the droplet level will regulate coalescence, assist contents mixing, and enable fast sorting in combination with analysis tools.
The next generation of wetting applications will require precise control and manipulation of individual droplets and will bring together soft matter physics, materials science and mechanical engineering. To achieve this, we need a better understanding of how droplet adhesion develops, not only at the onset of motion but also in a complex dynamic process.
The PhD student is expected to develop a protocol for experimental measurement of droplet adhesion forces following Dr Gao’s recent work on droplet motion (Gao et al., Nat Phy 2018). In addition, the PhD student will design and fabricate materials with liquid-repellent surface properties. By means of controlling droplet adhesion and motion, the student is expected to manipulate their spreading and separation behaviours, for example, at a multi-phased interface where one phase (e.g. oil) spreads and even penetrates through the interface easily while the other phase (e.g. water) is simultaneously repelled.
Students from a relevant discipline (Mechanical Engineering, Physics, and Chemistry) with strong research interest are encouraged to apply for the studentship. For informal enquiries, please contact Dr Nan Gao.