Larry Cheng cracks and wrinkles

Larry Cheng cracks and wrinkles

Four grey boxes are on a black background. The left shows tiny cracks, while the right has little wrinkles.

Researchers found that treating the same material at different stages of preparation could produce controllable valves for microfluidic devices. On the left, the material was stretched after treatment, resulting in cracks. On the right, the material was stretched before treatment and released, producing wrinkles. The bottom images are close ups of a crack and a wrinkle, respectively.

IMAGE: Huanyu "Larry" Cheng/Penn State