Thermally‐Triggered Structural Color Printing with Excellent Environmental Tolerance

Abstract Thermal printing occupies an advantageous position in the market competition due to its advantages of rapid response, superior print quality, and ease of operation. Despite the growing interest in thermochromic paper, there is a need for further development to enhance the color printing capabilities and information storage stability. Herein, a novel thermally‐triggered structural color printing with excellent environmental tolerance has been developed by integrating an inverse photonic glass (IPG) structure from the crystalline polythiourethane (PTU) polymer. The IPG structure, primarily exhibiting a white structural color opaque state, undergoes a permanent and irreversible transition to a highly transparent state upon thermal triggering. The mechanism behind it is rooted in the thermally‐triggered melting transformation of PTU during phase change process, resulting in rapid and irreversible collapse of porous structures. The stark contrast between structural color and transmittance opens up the possibility for thermal printing. Most importantly, the multilayer IPG/PSF/IPG structure, which incorporates polysulfide (PSF) microsphere arrays as color rendering layers, offers the potential for color printing. By adjusting the sizes of PSF microspheres (195, 233, and 248 nm), green, orange, and red color printing can be easily achieved. Notably, this strategy ensures the environmental tolerance and environmental friendliness of thermal printing.