Adhesion of Patterned Reactive Interfaces

We demonstrate the role of chemical surface patterns on the adhesion of soft, elastomeric interfaces. The microscale patterns consist of periodic variation of two types of silane surface chemistries: a reactive silane that bonds covalently with the soft elastomer and a passive silane that is weakly adhered with the elastomer. Using an adhesion test based on 90° peel geometry, we demonstrate that the tuning of adhesion depends on the spatial distribution of the reactive silane groups. Given our material system and pattern symmetries, an enhancement in adhesion energy is observed in a majority of the patterns. The mechanism of enhancement is associated with the shape of the contact line. Specifically, the reactive silane interfaces play a significant role in defining the width of the contact line. In instances where enhancement is observed, the width of the contact line increases because of the “pinning” of the contact line by the reactive interfaces. These results emphasize the importance of contact line interaction with the pattern shapes and demonstrate opportunities for using well-defined two-dimensional patterns to actively tune polymer adhesion.