Self-healing Materials

Prof. Wataru Nakao, Faculty of Engineering Science

Laboratory Overview

Our laboratory conducts research on advanced composite materials that utilize chemical reactions as one function. The advanced composite materials mimic the dynamic functions of living organisms as new materials concept. And the composites have the potential to become fundamental materials that support society 50 years from now. One example is self-healing ceramics, which are attracting attention as next-generation aircraft materials.

About Self-healing materials

Self-healing materials are new materials that can detect and repair damage themselves. Most self-healing is manifested by generating chemical reactions. Expressing the function by generating a chemical reaction is similar to the self-healing function of the living body, and is a new material of the next generation that mimics the dynamic function of the living body.

In the field of self-healing materials research, advanced research and development are conducted in a wide range of fields, including polymer materials, coating materials, composite materials, metal materials, ceramic materials, and concrete. Its applications include a wide range of applications, from kitchenware to space structures.

Examples of Self-Healing Materials

Self-healing material containing all reactants in the material in advance

ex) S.R White et al., Nature, 409, 794-797, (2001)

Self-healing material utilizing substances in the surrounding environment

ex) K. Ando et al., Fatigue Fract. Eng. Mater. Struct. 27, 533–541, (2004)

Self-healing material that collects necessary substances from the surrounding environment

ex) H. Jonkers, Ecological Engineering. 36, 230–235, (2010)

New value created by self-healing properties of materials

Life prolongation, Maintenance free

During the self-healing property is effective, the characteristics can be only slowly attenuated or substantially kept constant, thereby longer life and maintenance-free of the element are realized.

Environmental adaptability (Only self-healing materials that can restore full function)

Each time self-healing occurs, the defective part disappears, so that the function is improved. = Enables use of initial defective products.

Benefits of working with new materials at university

For new materials with unprecedented functions, such as self-healing materials, to be put to practical use, a long R & D period of more than 20 years is required. For this reason, cooperation with various researchers and engineers, such as social situation analysis and international cooperation, is required. Through these experiences, it is possible to acquire “communication skills”, which is one of the characteristics of Yokohama National University students, at a high level.