Mechanochromic Fluorescent Ionogels for Puncture-Resistant Soft Materials with Real-Time Stress Mapping

Ionogels, polymer networks swollen with ionic liquids, have emerged as promising candidates for soft robotics and biomedical devices. However, their resistance to stress corrosion, a critical yet underexplored failure mechanisms, remains poorly understood. Here, we developed mechanochromic fluorescent ionogels that simultaneously achieve excellent puncture resistance and real-time, molecular-level stress mapping. Incorporating rhodamine mechanophores as force-sensitive crosslinkers using the in situ micellar copolymerization method endows the ionogels with tunable mechanical properties, including toughness up to 51.1 MJ·m^-3 and puncture resistance exceeding 50 N. In addition, pixel-level stress mapping during puncture enables real-time visualization of crack initiation and propagation, uncovering how indenter geometries, interfacial friction, and puncture rate govern puncture mechanics. This work establishes a platform for probing localized large stress and failure mechanisms in soft matter, paving the way for next-generation protective membranes for biomedical and engineering applications.