Sensitive mechanical compression-patterned phosphorescence in the rubbery state of cross-linked polymer network

The molecular motion of polymer chains inevitably quenches phosphorescence at temperatures higher than the glass transition temperature (T_g). Therefore, modulating phosphorescence at relatively high temperatures presents a significant challenge. Herein, we report a dye-doped, cross-linked epoxy resin with sensitive mechanical compression-patterned phosphorescence. The temperature range over which phosphorescence occurs can be modulated by the T_g values of the epoxy resins. The resulting doped material exhibits visible, long-lived phosphorescence at temperatures as high as 150 °C. Furthermore, we demonstrate sensitive, spontaneously reversible mechanical compression phosphorescence characteristics in the rubbery state of the cross-linked network. At compressive stresses as low as 11 kPa, the phosphorescence is significantly triggered and can spontaneously recover to its initial state within 13.7 sec, maintaining consistent thermal-mechanical coupling response properties over 12 cycles. Our study systematically explores the embedding of phosphorescent dyes in polymer matrices and comprehensively analyzes the effects of free volume, mechanical force, and temperature on phosphorescence properties, thus establishing a foundation for future practical applications in sensing and information storage across a wide temperature range, particularly in high-temperature environments.