Research Background
Our main concern is kinetics, especially in chemical reactions, drying and flow of complex fluids (suspensions, emulsions and foams).
For example, evaporation of water spontaneously occurs. When involatile components are contained in water, they are concentrated and finally packed or precipitated.
How those condensation and packing(or precipitation) occurs during drying? This is one of the fundamental questions in our lab. Starting from this simple question, we have revealed several interesting topics, such as packing kinetics of colloidal particles, drying-induced flow of colloidal suspensions, reversibility in packing of colloidal particles, measurement of drying-induced compressional force for particles and packing of binary colloidal particles.
The above examples are results in which we used suspended hard particles, but our interests cover deformable particles as well. Liquid droplets (emulsions) and assemblies of bubbles (foams) are examples of "deformable droplets" and deformation of liquid-liquid or liquid-air interfaces are key issues in evaporation kinetics and flows.
We have also studied reaction of SiCl4 to form solid silicon. Gas phase reduction of SiCl4 by zinc vapor contains a lot of complicated processes. Formation of liquid zinc droplets during reaction is one of the examples and they act as catalyst for crystal growth of silicon.
Effects of reaction temperatures, flow of gases on morphologies and sizes of silicon solids are studied.
These phenomena are away from an equilibrium and kinetics is essencially important.