Accordingly, they designed elastomer films with inhomogeneous patterning of Young's modulus through selective UV illumination. The scientists accomplished this using horizontal and vertical photomasking slits, creating patterns of soft and rigid sections. On testing the horizontal patterned films under stress, the rigid sections hardly showed any deformation, whereas the soft sections showed 5 times elongation. Surprisingly, however, the vertically patterned films showed excellent toughness and delayed the propagation of cracks. While a crack on a fully rigid film propagates instantly, a crack on the inhomogeneous film stopped on reaching the soft section. The more the number of patterns, the slower was the growth of the crack.
"Our findings can provide useful insights for developing new methodologies for controlling the fracture behavior of elastomers," comments Dr. Hayashi, speaking of the practical ramifications of their study. "In addition, our technique could help save excess chemical consumption, and solve problems associated with depletion of petroleum resources," he adds.
These versatile films are sure to find applications in a diverse range of fields and pave the way to sustainable societies!