New self-healing polymer has shape memory and is recyclable

Researchers at Texas A&M University and the US Army Combat Capabilities Development Command Army Research Laboratory have developed a new family of synthetic materials ranging in texture from very soft to extremely rigid. The new material was created by tweaking the chemistry of a single polymer.The result is a new material that is 3D printable, self-healing, recyclable, and naturally adheres to each other in air or underwater. The scientists say that the group of materials have properties that can be fine-tuned to either the softness of rubber or the strength of load-bearing plastics. Materials are able to self-heal within seconds and are 3D printable, making them ideally suited for more realistic prosthetics and soft robotics.

Researchers say that the material also has a broad range of military applications, including agile platforms for air vehicles and futuristic self-healing aircraft wings. Synthetic polymers are made up of long strings of repeating molecular motifs like the beads on a chain. An elastomer has long chains that are lightly cross-linked, giving the materials a rubbery quality.

The researchers say that the cross-links can also be used to make the elastomers more rigid by increasing the number of cross-links. The team focused on a parent polymer called prepolymer. They chemically studded the material with two types of small cross-linking molecules – furan and maleimide.

When the number of those molecules increased in the prepolymer, they found they could create stiffer materials. The hardest material made in this method was 1000 times stronger than the softest. The furan and maleimide are able to anticipate the type of reversible chemical bonding that allows them to click and unclick together depending on temperature. At high temperatures, molecules come apart in the material softens while at room temperature, the material hardens to form cross-links. Future studies will attempt to increase the functionality of the material by amplifying its properties.