Hydrogel could be useful in a wide range of fields from making swathes up to soft robot manufacturing if it were stronger, not being reliable enough as it is. Attempts were made to reinforce it which finally succeeded thanks to a team of Hokkaido University researchers. They came up with a fresh idea to reinforce hydrogels with a fabric of woven fiber – and the resulting set of composites proved to be tougher than carbon steel by five times!
People have been using composites since God knows when mixing a reinforcing element into a substance that is too soft for the purpose. Thus, mud was mixed with straw to be made strong enough for making bricks, ceramic was made stronger through adding seashells, and plastic was tempered by glass fiber.
This was the idea that was used in treating hydrogel to enhance its qualities. Hydrogels are, scientifically speaking, chains of hydrophilic polymer which absorb quite a lot of water, about 90%, and therefore can’t be very durable or tough. But with tiny glass fibers added it suddenly becomes much stronger, giving itself to bending and stretching.
The researchers aver that their hydrogel-based composites are extremely strong presumably owing to dynamic ionic bonds that eventuate between the fiber and the hydrogels. It has been proved by tests where the material was destroyed and the energy used for the destruction calculated. The tests were conducted on polyampholyte gels and a single 10μm-diameter glass fiber and showed the resulting composite to be 25 times as strong as glass fiber fabric and five times the strength of carbon steel. Hydrogels become stronger than before by 100 times.
The members of the team state that, besides being durable and reliable, the fiber-tempered hydrogels that contain 40% water are environmentally safe. Now, due to its flexibility and the ability to withstand loads, the new composites can be employed in the production of various needfuls, including fashion items and medicine – they can assist in making artificial ligaments and tendons.