CO2‐Sourced Polymer Dyes for Dual Information Encryption

Large amounts of small molecule dyes leak into the ecosystems annually in harmful and unsustainable ways. Polymer dyes have attracted much attention because of their high migration resistance, excellent stability, and minimized leakage. However, the complex synthesis process, high cost, and poor degradability hinder their widespread application. Herein, green and sustainable polymer dyes are prepared using natural dye quercetin (Qc) and CO2 through a one‐step process. The CO2‐sourced polymer dyes show strong migration resistance, high stability, and can be degraded on demand. Additionally, the CO2‐sourced polymer dyes showed unique responses to Zn2+, leading to significantly enhanced fluorescence, highlighting their potential for information encryption/decryption. The CO2‐sourced polymer dyes can solve the environmental hazards caused by small molecule dye leakage and promote the carbon cycle process. Meanwhile, the one‐step synthesis process is expected to achieve sustainable and widespread utilization of CO2‐sourced polymer dyes. This study developed eco‐friendly polymer dyes through a one‐step process using quercetin, a natural dye, and CO2. The polymer dyes exhibit exceptional resistance to migration, long‐term stability, and degradability as needed. Their distinctive reaction to Zn2+ resulting in significant fluorescence enhancement further highlights their potential for advanced applications in information encryption/decryption.