Fiber-Reinforced Hydrogel Proves Stronger Than Steel

A new study describes novel fiber reinforced soft composites (FRSCs) that could be used to manufacture biocompatible ligaments and tendons.

Under development at Hokkaido University (Japan), the FRSCs are fabricated by combining polyampholyte (PA) hydrogels and glass fiber fabric within a single fiber measuring around 10μm in diameter. The melding of the hydrogels, which contain high levels of water, and the tough glass fiber fabric, create bendable materials that exhibit excellent tensile properties. When used alone, FRSCs are 25 times tougher than glass fiber fabric alone, and 100 times tougher than hydrogels alone, in terms of the energy required to destruct them.

The synergistic effect is thought to be a result of dynamic ionic bonds created between the fiber and hydrogels and within the hydrogels themselves, as the fiber’s toughness increases in relation to that of the hydrogels. Consequently, the newly developed hydrogels are five times tougher than carbon steel. The researchers have begun collaborating with different companies in order to develop FRSCs into new products in the field of artificial cartilage. The study was published in the March 2017 issue of Advanced Functional Materials.

“The fiber-reinforced hydrogels, with a forty percent water level, are environmentally friendly. The material has multiple potential applications because of its reliability, durability, and flexibility,” said senior author Professor Jian Ping Gong, PhD. “It could be used as artificial ligaments and tendons, which are subject to strong load-bearing tensions. The principles to create the toughness of the present study can also be applied to other soft components, such as rubber.”

Hydrogels are polymeric materials capable of holding large amounts of water (up to 80% for amorphous gels, 90% for sheet gels) in their three-dimensional (3D) networks. Hydrogels are able to absorb water as due to the hydrophilic functional groups attached to the polymeric backbone, while their resistance to dissolution arises from cross-links between network chains. Many materials, both natural and synthetic, fit the definition of hydrogels.

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