Researchers have developed a new class of materials, known as glassy gels, that combine the stiffness of glassy polymers with the stretchability of gels.

These materials retain more than 50% of their liquid content, increasing their flexibility and adhesive properties. The manufacturing process involves mixing polymer precursors with an ionic liquid and curing with UV light; This provides the potential for easy manufacturing and widespread application in industries such as electronics and medical devices.

Scientists have created a new class of materials called “vitreous gels”

Scientists have invented a new class of materials called “vitreous gels” that are extremely hard and difficult to break, even though they are more than 50% liquid. Combined with the fact that glassy gels are easy to produce, this material is promising for a wide range of applications.

Gels and glassy polymers are classes of materials that have historically been viewed as distinct from each other. Glassy polymers are hard, tough and often brittle. They are used to make things like water bottles or airplane windows. Gels, like contact lenses, contain liquid and are soft and elastic.

Innovative material design

“We have created a class of materials we call glassy gels, which are as stiff as glassy polymers, but can stretch up to five times their original length without breaking if you apply enough force,” says Michael. The corresponding author of the paper on this study is Dickey and Camille and Henry Dreyfuss, professor of chemical and biomolecular engineering at North Carolina State University. “In addition, the material can be returned to its original shape by applying heat after stretching. Additionally, the surface of glassy gels has unusually high adhesion for solid materials.”

“The main feature of glassy gels is that they are more than 50% liquid, making them more efficient electrical conductors than conventional plastics with similar physical properties,” says Meixiang Wang, a postdoctoral researcher and one of the lead authors of the paper. North Carolina State Surveyor.

“We are optimistic that these materials will be useful, given the number of unique properties they have,” Wang says.

Production and features

Vitreous gels, as the name suggests, are actually a material that combines some of the most attractive properties of both glassy polymers and gels. To make these, researchers start with liquid glassy polymer precursors and mix them with an ionic liquid. This combined liquid is poured into a mold and exposed to ultraviolet light, which “hardens” the material. The mold is then removed, leaving a glassy gel.

“An ionic liquid is a solvent like water but composed entirely of ions,” Dickey says. “Normally, when you add a solvent to a polymer, the solvent pulls the polymer chains apart, making the polymer soft and flexible. This is why a wet contact lens is flexible and a dry contact lens is not flexible. In glassy gels, the solvent separates the molecular chains in the polymer, allowing the polymer to stretch like a gel. But “The ions in the solvent are strongly attracted to the polymer, inhibiting the movement of the polymer chains. The inability of the chains to move is what makes it glassy. The result is that although the material hardens due to gravity, it can still stretch over an extra distance.”

Versatility and application potential

The researchers found that glassy gels can be made with a variety of polymers and ionic liquids, but not all classes of polymers can be used to create glassy gels.

“Charged or polar polymers are promising for glassy gels because they are attracted to the ionic liquid,” says Dickey.

During testing, researchers found that the glassy gels did not evaporate or dry even if they were 50-60% liquid.

“Perhaps the most interesting feature of glass gels is how sticky they are,” says Dickey. “Because even though we understand what makes them hard and flexible, we can only guess what makes them so sticky.”

Practical applications and future prospects

The researchers also believe that glass gels are promising for practical applications because they are easy to make.

“Making a glass gel is a simple process that can be done by solidifying it into any shape or by 3D printing,” says Dickey. “Most plastics with similar mechanical properties require manufacturers to create the polymer as a feedstock and then transport that polymer to another facility where the polymer is melted and converted into the final product.

“We are excited to see how glassy gels can be used and look forward to working with our colleagues to identify applications for these materials.” The article “Solvent-enhanced glassy gels” was published June 19 in the journal Nature.