Restraint İmproves Dielectric Performance,Lifespan

Just as a corset improves the appearance of its wearer by keeping everything tightly together, rigidly constraining insulating materials in electrical components can increase their energy density and decrease their rates of failure. Many electrical components, like wiring, are typically surrounded by a material that keeps the electricity from passing to its surroundings. These insulating materials are known as dielectrics, and can take many forms, with the most common being "soft" materials known as polymers. However, since these dielectrics are constantly being submitted to electrical voltage, they tend to break down.

Duke University engineers have demonstrated that rigidly constraining dielectric materials can greatly improve their performance and potentially lengthen their lifespans. This insight follows their discovery earlier this year of the exact mechanism that causes soft dielectric materials to break down in the presence of electricity.

"We found that increasing voltage can cause polymers to physically crease and even crater at the microscopic level, eventually causing them to break down," said Xuanhe Zhao, assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering. "So we thought if we wrapped the polymer tightly, that would prevent this creasing from occurring. Experiments proved this hypothesis to be true."

The results of the Duke study were published online in the journal Applied Physical Letters.

In their experiments, the Duke researchers constrained three different soft polymer dielectrics with epoxy. Epoxy is a type of polymer created by the reaction of a resin with a hardening agent. When mixed, a hard and inflexible coating is formed.