Crumpled Matter for Roughness Tolerant Adhesion

Effectively adhering to rough surfaces can be a challenge. Strong adhesion typically relies on maximizing three factors: chemical interactions, contact area, and stiffness. On a rough surface balancing the compliance and contact area is especially challenging as low compliance adhesives are unable to achieve high contact area as the adhesive is unable to deform around obstacles. High compliance adhesives are able to deform around surface obstacles creating a high contact area but fail at lower peak forces due to the decreased stiffness. In the experiments described here, a crumpled, inextensible, and sticky sheet is used to create a rigid, but high contact adhesive bond. Specifically, sheets of various controlled polymer materials were crumpled and force-displacement curves were measured with two parallel glass plates. Next, the crumple was tested against a controlled obstacle added and compared to the data from the flat glass walls. We show that there is no significant difference between the adhesion of the crumple on smooth or “rough” surfaces.