Programmable Structural Color Lifetimes via Activation Energy Engineering for Spatiotemporally Encoded Dynamic Optical Encryption

ABSTRACT

Spatiotemporally programmable structural color holds great promise for high‐security optical encryption, yet precisely tailoring the lifetime of structural color across a broad temporal range spanning multiple orders of magnitude remains a significant challenge in polymer systems. The lifetime of structural color is intrinsically governed by the segmental relaxation kinetics of the underlying polymer network, which has been largely overlooked in the rational design. Here, we report a dynamic surface grating with programmable structural color lifetime, in which the optical evolution process is precisely encoded by tuning the activation energy through crosslinking density and amplitude control. Driven by segmental relaxation, the grating amplitude gradually decays over time, redistributing diffracted energy back to specular reflection and causing a gradual fading of structural color. By spatially encoding the relaxation activation energy via photomask‐assisted UV exposure, the structural color lifetime governed by local amplitude decay kinetics can be independently programmed across different regions, spanning an unprecedented temporal range from 300 s to over 240 days. This strategy enables diverse applications, ranging from stimulus‐responsive optical encryption and time‐resolved multilevel information encryption to practical cold‐chain integrity monitoring, establishing activation energy as a broadly applicable handle for temporal programmability in dynamic optical systems.