New results have been made in ongoing hydrogel research at Hokkaido University, where they have found a new polymer-based material that, unlike other polymers, can harden 1,800 times after heating. At room temperature, the substance is a soft transparent gel. But heated to 60 degrees C (140 degrees F), it hardens, becomes opaque and strong enough to withstand a weight of 10 kg (22 lb).
Hokkaido researchers Takayuki Nonoyama and Jian Ping Gong are apparently inspired by the natural proteins that remain stable in the body of heat-addicted bacteria, which are organisms that live in extreme lymes such as hot springs or deep-sea hot vents. At this ambient temperature, proteins usually denature, but the proteins inside the pyrophilia have adapted to the high temperatures to remain stable.
By immersing polyacrylic acid in a calcium acetate solution, the team was able to develop a cheap, safe polyacrylic gel. Like any polymer-based material, polyacrylic acid heating softens, but when calcium acetate is applied, polyacrylic acid interacts with the polyacrylic residue on the surface, creating a transformative effect. At about 60 degrees C, the material is effectively dehydrated, enhancing its ion bonds and becoming a sturdy hard plastic. Not only can it harden 1,800 times, but it is 80 times stronger and 20 times stronger than room temperature gels.
The researchers then combined the gel with fiberglass fabric. The mixture is soft at room temperature, but when pulled along the asphalt at a speed of 80 km/h (50 mph) for 5 seconds, the material hardens due to the heat generated by strong friction. The choice of asphalt is significant, and one day this fast hardening material will provide extra protection for motorcyclists and racers in the event of an accident. The researchers also recommend applying the material to windows to absorb heat and keep the building’s interior cool.