To understand the phenomena that occur at colloid and fluid-fluid interfaces, it is essential to study the behavior of atoms and molecules on very small length scales and very short time scales. In our laboratory we use various simulation tools to understand interfacial phenomena that are difficult to observe experimentally. We are currently performing density functional theory (DFT) and molecular dynamics (MD) simulations to determine the orientation and reactivity of molecules at interfaces, in order to theoretically understand various experimental phenomena such as adsorption, reaction and mass transfer at fluid interfaces. In addition, we work not only on small length scale systems, but also on theoretical designs for the application of microscopic reactions to large scale process systems. To this end, we carry out fundamental and applied research into the design and optimization of complete process systems based on fluid mechanics and rheology.