Flaw-Tolerant Fracture Enabled by Liquid-like Elasticity in Liquid Crystal Elastomers

Abstract

Polydomain liquid crystal elastomers (P-LCEs) with randomly oriented directors exhibit extraordinary in-plane liquid-like mechanical properties, attributed to the minimal energy cost of local nematic director rotation, distinguishing them from conventional elastomers. This study reveals that during tensile tearing, notched P-LCEs demonstrate exceptional strain homogenization across the specimen, effectively mitigating the crack-tip strain concentration and suppressing crack-tip opening over a broad range of applied stretching until the polydomain-to-monodomain transition threshold. This unique capability significantly delays macroscopic fracture. Compared with conventional elastomers, the reduction in fracture strain caused by notching is substantially smaller in P-LCEs, underscoring the critical role of strain homogenization in enhancing fracture resistance. Our findings contribute to a foundation for designing polymer-based soft materials with superior mechanical properties and fracture resistance