Researchers at MIT have developed a thin, light-weight film that can securely adhere to flexible and deformable parts of the body, such as the knee and elbow. The key to the sticking-power of the material lies in a series of slits the researchers have cut into it, inspired by the Asian art of kirigami, which involves cutting and folding paper.
The research team was approached by a Chinese company that manufactures a popular pain-relieving bandage to develop a version that can adhere to joints such as the elbow and knee. “Adhesives like these bandages are very commonly used in our daily life, but when you try to attach them to places that encounter large, inhomogenous bending motion, like elbows and knees, they usually detach,” said Ruike Zhao, a researcher involved in the study. “It’s a huge problem for the company, which they asked us to solve.”
The researchers turned to the ancient Asian art of kirigami to develop their solution. Kirigami involves cutting intricate patterns into paper, and then folding it into complex shapes, and is similar to origami. The research team created flexible sheets by pouring rubber or elastomer into 3D-printed molds, and the cured sheets were studded with rows of off-set slits.
By applying a layer of adhesive to one side of the sheets, the researchers were able to adhere them to a volunteer’s skin, just like a regular bandage. Even after 100 knee bends, the kirigami-inspired sheet did not detach from the volunteer’s knee, in contrast to an intact sheet with no slits, which detached very quickly.
The research team discovered that the slits in the kirigami-inspired sheet separated at the areas of most pronounced bending, and remained closed and adhered to the skin in other areas, allowing the sheet to deform without detaching.
While the kirigami-inspired sheets are likely to be very useful for bandages, other applications include wearable electronics, medical sensors and drug delivery patches. “The current films are purely elastomers,” said Zhao. “We want to change the film material to gels, which can directly diffuse medicine into the skin. That’s our next step.”
Study in journal Soft Matter: Kirigami enhances film adhesion…