The solid particles are irreversibly adsorbed to the interface of two immiscible fluids, and consequently lower the interfacial tension of the fluid. Further, various functional groups can be introduced into the surface of the solid particles to finely control the degree of the surface activity, and these particles can be applied to various industrial fields that can substitute environmentally and inexpensively the molecular surfactants.
Microfluidic fabrication of functional particles & emulsions
The microfluidic device is a system in which a small amount of fluids is injected into each capillary channel and droplets are periodically formed in a region where each fluid converges. It can be used for the material delivery system by including various kinds of ingredients in each fluid in advance. It is also possible to tune the anisotropy of the particles and emulsion by controlling the interfacial tension between the fluids.
Crystal growth reaction in microemulsion reactors
The crystal growth reactions can be induced in the emulsions produced by the microfluidic device. Since the size of the emulsion is several tens to several hundreds of micrometers, it is possible to monitor the real-time crystallization reaction using a conventional optical microscope, and thus it can be useful for reaction mechanism analysis.
Micromixing for microemulsion reactors
As the chemical reaction proceeds in the microemulsion reactor, stirring effect in the fluid can still be an important factor. However, such studies have not been actively performed so far. Quantitative studies are conducted in which the degree of agitation affects the kinetics of the chemical reaction by using agitable anisotropic microparticles in a microemulsion reactor or by using optical laser tweezers to agitate a small volume of fluid.
Colloid interface phenomena
The colloidal particles are irreversibly adsorbed at the fluid interface to lower the interfacial tension, and thus the stable Pickering emulsions can be produced and applied to various industrial fields. The electrostatic force and the capillary force acting between the particles when the particles are present at the fluid interface are abnormally strong. Such interaction forces can be measured quantitatively using optical laser tweezers. By controlling the relative strength of the repulsive and attractive forces, it is possible to control their assembly, microstructure, and rheological properties of the particle-laden interface.