Experimental and theoretical analyses of curvature and surface strain in bent polymer films

Understanding the curvature of a bent polymer film is important for the research and development (R&D) of flexible electronic devices. Herein, we report that the curvature of a polymer film is successfully predicted by a stress-strain curve (S-S curve) of the polymer. The curvature of a bent polymer film depends on film thickness and chemical structure, which is experimentally confirmed. This dependence is demonstrated well by our theoretical model (the modified Elastica theory) based on a S-S curve. This method provides effective guideline for the R&D of flexible electronic devices.