Weakened adhesion on elastic film via patterned adhesion

Abstract

High strength of adhesion is vital for various creatures and engineering applications. However, strong adhesion between printed parts and the release film turns out to be an insurmountable obstacle in digital light processing (DLP) 3D printing technology, and adhesion weakening is highly desired to speed up the fabrication efficiency. In this work, a strategy of sector pattern is proposed to reduce the adhesion force of a rigid punch detaching from a pre-stretched film. A theoretical model is proposed and solved by Fourier–Bessel series method to analyze the decohesion mechanism. Complemented by finite element simulations, we see that the reduction ratio of pull-off force can be attributed to the shortened ratio of periphery length. The sector pattern of the adhesive area ratio $1/2$ has the reduction ratio of $1/\sqrt{2}$ for JKR limit (film of low stiffness, strong interfacial adhesion) and $1/2$ for DMT limit (film of large stiffness, low interfacial adhesion). The theoretical and numerical results are validated experimentally by decohesion between printed cylinder parts and a fluorinated ethylene propylene (FEP) film. Our study may deepen the understanding of the decohesion mechanism of patterned adhesion and provide a design criterion for reduced pull-off force in DLP 3D printing and similar engineering applications.