Embedding topography enables fracture guidance in soft solids

Abstract

The natural topographical microchannels in human skin have recently been shown to be capable of guiding propagating cracks. In this article we examine the ability to guide fracture by incorporating similar topographical features into both single, and dual layer elastomer membranes that exhibit uniform thickness. In single layer membranes, crack guidance is achieved by minimizing the nadir thickness of incorporated v-shaped channels, maximizing the release of localized strain energy. In dual layer membranes, crack guidance along embedded channels is achieved via interfacial delamination, which requires less energy to create a new surface than molecular debonding. In both membrane types, guided crack growth is only temporary. However, utilizing multiple embedded channels, non-contiguous crack control can be maintained at angles up to 45° from the mode I fracture condition. The ability to control and deflect fracture holds great potential for improving the robustness and lifespan of flexible electronics and stretchable sensors.

Biomechanical fracture mechanics of composite layered skin-like materials

“…The necessary volumes were obtained by extrapolating the volume used for early preliminary samples and the corresponding final thickness obtained. The 5 : 1 and 55 : 1 layers respectively exhibit an elastic modulus of E = 16 kPa and E = 1.48 MPa, 29,30 chosen to be as widely varying as possible for this elastomer.…”