CHARLOTTESVILLE, Va.—Students at the University of Virginia School of Engineering and Applied Science have developed a new polymer design that may bridge the gap between rubber elasticity and stiffness.
The new design, known as the "foldable bottlebrush polymer network," is the second major rubber research breakthrough this month. The polymer design is the brain child of Ph.D. student Baiqiang Huang and Liheng Cai, assistant professor of materials science and engineering, and chemical engineering.
"This limitation has held back the development of materials that need to be both stretchable and stiff, forcing engineers to choose one property at the expense of the other," Huang said.
The project was funded by Cai's National Science Foundation Career Award. The design is shaped like a bottlebrush, giving it one central "spine" and multiple flexible chains on the side, rather than a normal linear polymer.
The new material design is fully 3D printable, according to university reports, and can also be mixed with inorganic particles that would allow the material to take on electric, magnetic or optical properties.
"Our team realized that by designing foldable bottlebrush polymers that could store extra length within their own structure, we could 'decouple' stiffness and extensibility—in other words, build in stretchability without sacrificing stiffness," Cai said. "Our approach is different because it focuses on the molecular design of the network strands rather than crosslinks."
The research team already has lined up quite a few possible applications for the new material. Huang and his team cited the new polymer as a way to design "muscles" for robotic systems, as well as prosthetics, medical implants and wearable electronics.
"We are addressing a fundamental challenge that has been thought to be impossible to solve since the invention of vulcanized rubber in 1839," Cai said.
"These components give us endless options for designing materials that balance strength and stretchability while harnessing the properties of inorganic nanoparticles based on specific requirements."
