Microcapsule‐Based Self‐Reporting Materials: Moving Beyond Detection Toward Quantification of Microscale Damage

Inspired by biological systems that can visualize damage through optical signal such as bruising or bleeding, microcapsule‐based self‐reporting materials offer a promising strategy for autonomous detection of mechanical stress. These systems embed dye‐filled microcapsules in polymer matrices, which rupture under stress to release optical signals. However, most of these systems only indicate whether damage has occurred, without providing information about how much damage or force was involved. This concept paper introduces self‐reporting microcapsule systems and explores how they can be further developed to quantify microscale mechanical damage. Recent innovations enable force quantification through intensity‐based outputs, ratiometric spectral shifts, multilayer capsule architectures, and rupture threshold engineering. By overcoming the current limitation of damage detection, force‐resolved self‐reporting materials open new possibilities for smarter, safer, and more durable systems in aerospace and infrastructure.