A new class of materials combines the hard, stiff characteristics of glassy polymers with the soft and stretchy nature of gels. The glassy gels engineered by researchers from the University of North Carolina, North Carolina State University and University of Nebraska are difficult to break despite containing more than 50% liquid.

“We’ve created a class of materials that we’ve termed glassy gels, which are as hard as glassy polymers, but — if you apply enough force — can stretch up to five times their original length, rather than breaking,” explained the researchers. “What’s more, once the material has been stretched, you can get it to return to its original shape by applying heat. In addition, the surface of the glassy gels is highly adhesive, which is unusual for hard materials.”

Source: Meixiang Wang, North Carolina State University

A mixture of liquid precursors and an ionic liquid is poured into a mold and exposed to ultraviolet light to cure the material. The mold is then removed, leaving behind the glassy gel. Testing demonstrated that the materials do not evaporate or dry out, even though they consist of up to 60% liquid.

The glassy gels are also extremely adhesive, possess enormous fracture strength and can be deformed up to 670% strain with full and rapid recovery on heating. Applications in 3D printing, soft robotics and solid electrolytes are envisioned for the material described in Nature.