Emergence of instability-driven domains in soft stratified materials

Nature frequently employs the buckling phenomenon to facilitate the formation of complicated patterns across length-scales. Current knowledge, however, is limited to a small set of buckling-induced microstructure transformations in soft composites; and the pattern formation phenomenon remains largely unknown for a vast pool of material morphologies. Here, we investigate the unexplored rich domain of soft heterogeneous composites. We experimentally observe the formation of instability-driven domains in stratified composites with a non-dilute stiff phase. We illustrate that the discovered domain patterns are energetically favorable over wrinkling. Moreover, we introduce a closed-form analytical expression allowing us to predict the evolution of the patterns in the post-buckling regime. Finally, we show that various patterns can be pre-designed via altering material compositions. These findings can help advance our understanding of the mechanisms governing pattern formations in soft biological tissues, and potentially enable the platform for mechanical metamaterials.

Automated summary

The study discovered that in the unexplored field of soft heterogeneous composites, a non-dilute stiff phase can lead to the formation of instability-driven domains that are energetically favorable over wrinkling. By introducing a closed-form analytical expression to predict the evolution of the patterns and altering material compositions, various patterns can be pre-designed.