RIST Outline

Division of Colloid and Interface Science

Director  Takeshi Kawai:Professor, Department of Industrial Chemistry, Faculty of Engineering 
Research Content General research on surfaces and interfaces
Objetcitves To play a leading role in colloid and interface science both in Japan and internationally.

-The Research Highlight, 2016-

All physical objects have surfaces. A boundary surface (interface) also exists between two mutually contiguous objects. Interface science is a discipline that researches surfaces and interfaces.

Let us take, for example, a coarse spherical particle with a radius of 1cm. By crushing this particle, we can create a cluster of microparticles with a radius of 1μm. Since the total volume of the entire cluster of microparticles is the same as that of the coarse particle (4.2cm3), it is easy to calculate that we can create 1012 microparticles in this way (see the diagram below). The surface area of the coarse particle, however, is 12cm2 or 3cm by 4cm, about the same size as the palm of your hand. But when the coarse particle is crushed, the total surface area increases 10,000 times to 12m3 or 3m by 4m. In other words, the cluster of microparticles has an unbelievably large surface area. With such a large total surface area, the properties and behavior of the cluster of microparticles (colloid particles and nanoparticles) are determined by the properties of their surface area.

Colloid and Interface

Interface science has a broad range of application, and is related to a variety of fields including surface active agents (surfactants), microparticle (colloid particle and nanoparticle) dispersed systems, microcapsules, gel, solid surfaces, powders, bio-interfaces and environmental colloids.

The Division of Colloid and Interface Science was established in January 1981. The first Director, Professor Kenjiro Meguro (Department of Applied Chemistry, Faculty of Science) was succeeded by Professor Tamotsu Kondo (Department of Medicinal and Life Science, Faculty of Pharmaceutical Sciences), Professor Minoru Ueno (Department of Applied Chemistry, Faculty of Science), Professor Kijiro Konno (Department of Industrial Chemistry, Faculty of Engineering), Hiroyuki Ohshima (Department of Medicinal and Life Science, Faculty of Pharmaceutical Sciences), and Professor Takeshi Kawai (Department of Industrial Chemistry, Faculty of Engineering) leading up to the present incumbent. The members come from all faculties of TUS, and have played a leading role in interface and colloid science both in Japan and internationally.

The Division of Colloid and Interface Science had been shifted to the Center for Colloid and Interface Science during 2008~2013, because a project application was accepted as the MEXT Program for the Development of Strategic Research Bases. The project theme was “Creation and Application of Nano/Biointerface Technologies,” and the research unit consisted of 5 groups: biointerfaces, biomaterials, nanomaterials, nanospace, and interface theory/analysis. In this project, we approached the interface as the locus of temporospatial expression of function, and our goal was to create temporospatially controllable nano/biointerface technologies.

Now, we restarted the division of colloid and interface science with new members from April 2013. The main research project is the deeper understanding of dynamic surface phenomena of “soft interface” and “hard interface”. Here, “soft interface” is referred to a dynamic ineteface where molecules and atoms are continually going in and out thorugh the interface, whereas “hard interface” means a static interface where no exhange of molecules and atoms take place at the interface. The representative materials of the former are spherical and worm-like micelles, emulsions, vesicles and Gibbes monolayers, while the latter are metal nanoparticles and nanowires, nanoporous materilas made of organic complexes, self-assembled monolayers on solid substrates. “Soft interface” and “hard interface” can also be called “dynamic interface” and “static interface”, respectively, and the both interfaces are classified into three basic groups according to dimesions, namely, zero and three dimesion, one dimension and two dimension. We aggressively pursue the fully understanding of the fundamental phenonema and the fuctions at the both interfaces, and hope to achieve the development of novel functional materilas.

In this project, we are going to investigate intensively the role of water molecules present at interfaces such as solid-iquid, liquid-gas and solid-gas interfaces. It is general known that water molecules at interfaces play a crucail role in performances of various functional materials including biomaterials, however, the detailed functions and structure of water, and interactions beween substrate molecules and water remain unsolved.

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Future Development Goals

We afford a deep understanding of surface phenomena from fundamental aspects and the practical aspects by the assist of exchanges of information and closer collaboration between interdisciplinary researches. In particular, we give intensively attentions to “static and dynamic surface behaviors” and “dimension of target-objects”.

Messages

Every objects have surfaces, and there are interfaces between objects. Surface science is a science which studies surface phenomena emerged from restricted spaces at interfaces or boundaries, and covers a wide interdisciplinary research fields. Further, surface science has an interest side and some surface science researches pursuit conceptual understanding of the phenomena, although it is one of materials science. We sincerely hope that outcomes of our project will contribute to the progress of many other fields.

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