Reversible dynamic microenvironment switching enables sustainable black chromic printing

Journal article, 2026

(Figure presented.) In conventional chromic systems, the color-changing components are typically confined within a single, static microenvironment, making it extremely challenging to simultaneously achieve efficient coloration, long-term stability, and reversible erasure of the classic black state—a key bottleneck that has significantly hindered the adoption of chromic materials in sustainable printing and display applications. Herein, we present a novel “dynamic microenvironment switching” strategy that leverages commercially available dyes to realize the long-sought-after triad for high-contrast black display: on-demand display triggered by water, long-term stable-state retention, and on-demand reversible erasure. This design yields a predominantly bio-based, quasi-bistable chromic material that is compatible with existing printing technologies. It enables rapid transition from white to an ink-like, high-purity black with exceptional optical contrast (ΔR > 70%). The printed information remains stable for over six months without any energy input (ΔR6 months ≈ 60%), and can be erased on demand and rewritten for dozens of high-fidelity cycles. This work offers a promising pathway toward ecofriendly applications such as sustainable printed media, rewritable advertising displays, and reusable visitor cards. More importantly, the “dynamic microenvironment switching” strategy establishes a new paradigm for designing intelligent responsive materials that seamlessly integrate bistability with environmental sustainability.