From Stretch to Fracture: Unraveling and Quantifying the Mechanical Limits of Conjugated Polymer Films for Stretchable Electronics

ABSTRACT The rapid advancement of stretchable electronics has established conjugated polymers (CPs) as a cornerstone material class. However, the widespread adoption of CP‐based devices is critically limited by mechanical failure through cracking and fracture, which compromises long‐term operational reliability and functional integrity. This feature‐article bridges the critical gap between high performance and mechanical robustness by providing a systematic, multi‐scale examination of CP fracture behavior. We first consolidate advanced experimental methodologies for quantifying key mechanical metrics including fracture strain, fracture energy, and crack propagation dynamics in ultra‐thin films. The discussion then elucidates the governing factors of fracture resistance across length scales, from molecular architecture, such as backbone rigidity, molecular weight, and side‐chain, to macroscopic parameters like thickness, substrate, and environmental exposure. Subsequently, clear structure‐property relationships are established that dictate mechanical durability, with specific consideration given to neat CPs and complex polymer blend systems used in organic photovoltaics/photodetectors and light‐emitting diodes. Finally, the review outlines forward‐looking strategies to accelerate the development of fracture‐resistant CPs, emphasizing the need for standardized testing protocols, multi‐scale computational modeling, and morphology‐aware material design. This work aims to serve as a foundational guide for transitioning stretchable CPs from promising laboratory materials into reliable, high‐performance components for next‐generation wearable electronics.