Research Projects

This project aims to explore the multi-scaled, coupled transport phenomena of evaporation of droplets on a surface and squeezed between two parallel plates in the ambient and saturated alcohol environment. The study will test droplets of pure liquid, aqueous colloidal suspensions, and binary liquid colloidal suspensions. The project will investigate transient fluid dynamics, heat transfer, mass transfer of liquid vapor, and advection of particles in the droplet. The colloidal deposit's pattern, dimensions, and morphology depend on the underlying coupled transport phenomena or physical principles. A state-of-the-art setup will be developed, involving 2D micro particle image velocimetry and piezoelectric based droplet dispenser. Methods will be employed to record time-varying droplet shapes, liquid-gas interface temperature, particle motion, optical profilometry, and SEM. The project will address several fundamental open questions in this area due to the wide parameter space and complexity of the systems. These include how particle presence influences contact line motion and alters the colloidal deposit, how different flows inside an evaporating binary droplet affect the deposit, and how a capillary bridge with plates of different wettabilities affects evaporation dynamics and colloidal deposit. The coupled physics will be investigated for the variation of problem parameters such as particle size, concentration, substrate orientation, roughness, wettability, substrate temperature, and volume fraction of binary droplet. Regime maps based on competing transport phenomena will be proposed to classify different deposit types.