SCIENCE AND TECHNOLOGY

Aqua Material: Good for the Environment, Good for the Body

A team of researchers at the University of Tokyo led by Professor Takuzo Aida has developed a new type of hydrogel with potential applications in fields ranging from firefighting to cartilage replacement. The Japan Journal’s Osamu Sawaji reports.

It is transparent and very strange to the touch. The surface feels smooth and pleasantly cool. Like clay, pressing on it causes it to change shape, but it recovers its original form immediately. Like rubber, it stretches when you pull it but when you let go, it is restored to its original size.

Laughing, Professor Takuzo Aida of the University of Tokyo says, “Hard to believe it is 98% water, isn’t it? We named it Aqua Material because of the high water content.”

In January this year, Professor Aida and his research team announced the successful development of the Aqua Material, which is a type of hydrogel. Water is the main component in hydrogels, which have been used as materials for healthcare products such as contact lenses. However, Aqua Material is equipped with advanced functions and unique properties not found in the hydrogels of the past.

To start with, there is its strength. The strength of one person is not enough to tear it easily. Even if the material is damaged, it will be restored to its original state as long as its cut surfaces are put together again within one minute.

Another special feature is that it is extremely easy to make. You need naturally derived clay, sodium polyacrylate (ASAP), which is an absorbent used in disposable diapers, and a substance called a binder (dendritic macromolecules at both ends), which serves to bind the molecules. These ingredients are mixed with water at a constant rate and stirred for several seconds before hardening into the desired shape in a mold. That is all it takes. There is absolutely no need for heating.

Professor Aida explains, “The clay is derived from natural sources, and the organic matter contains in all no more than 0.2% of ASAP and binder. Since the water accounts for most of the ingredients, the material is not harmful to the body or the environment. No toxic substances are formed at disposal.”


Hydrogels have been researched in many countries with expectations for use in various fields. However, hydrogels made only by mixing ingredients had problems such as a lack of strength or high level of organic matter content which places stress on the human body and the environment.

At first, the hydrogel created by Professor Aida and his research team was also low in strength. A Chinese researcher who had played a central role in the experiments was the one to provide the idea for the improvements. He suggested that ASAP might be effective. In fact, when using ASAP, the strength of the gel increased all at once and it was also possible to obtain the added value of transparency, which is advantageous for product development. Professor Aida comments, “Many other research peers contributed their expertise and lent us a hand. Research is not something you can do alone. The Aqua Material is the product of the insights of many people coming together in an extremely good form.”


There are expectations for applying the Aqua Material to an array of fields in the future. Making use of its noncombustibility, a fire-extinguishing agent is one example. If a pot of oil accidentally catches fire while cooking, covering the pot with a sheet of Aqua Material should extinguish the fire safely. In addition, in the healthcare field, it may replace bones or cartilage, or be used as a material for covering wounds to the internal organs.

Although it needs to be handled with care because it quickly becomes unmalleable, the material has a major advantage in that anyone can manufacture it anywhere without any special tools or technologies as long as the ingredients are at hand.

At present, Professor Aida is getting a rush of inquiries about practical applications from numerous research institutes in Japan and abroad, and from companies including chemicals firms, toy makers and cosmetics manufacturers.

“The Aqua Material is a new material for the modern era that focuses on the environment. I am sure that in the future, it will be used in a variety of settings in our daily lives.”