Technological watch

Researcher from the University of Virginia School of Engineering has found a way to design a new synthetic soft rubber. Assistant professor Liheng Cai’s lab is focusing on designing the rubber to be recyclable and to have superior mechanical properties in the context of stiffness.
Dry and Stable Material Workable with Biological Tissues
Materials that interface with biological tissue in a living organism must not only be of similar stiffness to the tissue, they must also be stable. That is why Cai is focusing on a “dry” material. Typically, dry materials are very stiff – think of metal, glass, ceramics and plastic. While good for many uses, they’re not suitable for many medical applications.
The stiffness of the rubber to be made is more than 1,000 times softer than conventional rubber, such that it can be used to interface with biological objects.
Responsive Rubber for Multiple Applications
Although most rubbers are regarded as soft materials, they are still much stiffer than living tissue. Water can be added to rubber to make a hydrogel to interface with biological objects. However, diverse bio-applications require materials that do not leach molecules and change properties. To this end, researchers have designed polymers with controlled molecular architecture to make soft, yet ‘dry’ gels.
Another characteristic of the new rubber is to make it responsive to stimuli such as heat, mechanical force, light or acidity that can change it from solid to liquid or back again. This ability results in a new class of soft materials for 3-D printing that can be used in applications such as stretchable materials with embedded electronics; soft robots built from pliable, more life-like materials; optical devices; and tissue engineering.
“This program is driven by true need, especially from the biomedical application side,” Cai said. “My second motivation is curiosity for pushing the boundaries of material science and chemical engineering.”