Removable paint and self-healing plastics closer to reality

Researchers have developed new dynamic materials that could help make removable paint and self-healing plastics.

University of Illinois materials science and engineering professor Jianjun Cheng said that the key advantage of using this material is that it's catalyst-free and low-temperature, and can be healed multiple times, asserting that these are very nice materials for internal cracks, adding that they can heal the crack before it causes major problems by propagating.

Other self-healing material systems have focused on solid, strong materials. However, the new study uses softer elastic materials made of polyurea, one of the most widely used classes of polymers in consumer goods such as paints, coatings, elastics and plastics.

After the polymer is cut or torn, the researchers press the two pieces back together and let the sample sit for about a day to heal - no extra chemicals or catalysts required.

The materials can heal at room temperature, but the process can be sped up by curing at slightly higher temperatures (37 degrees Celsius, or about body temperature).

The polymer bonds back together on the molecular level nearly as strongly as before it was cut. In fact, tests found that some healed samples, stretched to their limits, tore in a new place rather than the healed spot, evidence that the samples had healed completely.

The researchers use commercially available ingredients to create their polymer.

The study has been published in the journal Nature Communications.