Wei, M., Han, J., Yu, C., Li, P., Zhang, X., Ding, J., Chen, M., Li, X., Yin, G., Zhang, T., Wang, J., Théato, P., Chen, T., Lu, W. (2026). Mass Diffusion‐Dominated Phase Separation Enabling On‐Demand and Repeatable Lifetime Programming of Room‐Temperature Phosphorescence Polymer Hydrogels. Advanced Materials. https://doi.org/10.1002/adma.202517109