The softness of a material is measured in terms of how easily it stretches and bends. Most elastomers generally have a high modulus, meaning they stretch and smash down very little. A low modulus would mean the material is very stretchy and soft. Conventional elastomers are stiffer and less stretchy than most biological tissue. However, ‘bottlebrush’ polymers have a structure that allows for extreme softness. Their structure contains polymers attached to a backbone like a bottlebrush; regular polymers are similar to cooked, mixed-up spaghetti. You can visualize the difference.

Researchers have developed a bottlebrush polymer that can be 3D printed. The result is an object that has remarkably soft, elastic properties. Properties that are very similar to human tissue. Being able to 3D print elastomers with such unique mechanical properties creates opportunity for new applications from implants to highly-sensitivity electronic devices.

The bottlebrush elastomer material begins as a soft solid, like butter, that will hold its shape until pressure is applied. At that point, it liquefies to a state that is capable of flowing. Scientists are able to control the pressure and therefore the amount of flow for individual processing applications. Once the object is printed, infrared light is applied to activate the crosslinks. The crosslinkers link neighboring polymers. The result is a super-soft, super-elastic solid with extraordinary properties.

The new material exhibits a modulus that is 1000 times smaller than a conventional elastomer, and can stretch three to four times its length. Since the new elastomer has similar mechanical properties as human tissue, implants made in this way can reduce inflammation and rejection by the body.

The Polymers Center helps companies research materials through a wide variety of tests in our testing laboratory. We can help develop prototypes and processes for creating new products. Contact us to learn more about how we can work hand in hand with your company’s research and development team.