A facile strategy to achieve room-temperature organic long afterglow from melt processible, new two-dimensional polyamide doped γ-polyamide 6

Organic long afterglow materials can be incorporated into commercial polar polymer in very small amount to significantly reduce cost for application, while gaining excellent mechanical deformability attractively. Their luminescence can be usually enhanced, as the polar polymer can block oxygen diffusion and inhibit inclusion aggregation. However, due to thermal instability of most afterglow materials at high temperature, it is still a great challenge when they are applied for widely used polymer melt in material industry. Herein we report a new afterglow material of doped polymer system by blending a new luminescent, two-dimensional polyamide sheet (TIB-3CPBA-TAPA) with a high-temperature polyamide 6 (γPA6) melt. The excellent thermal stability of TIB-3CPBA-TAPA results from the amide bond-linked, imidazolium salted and conjugated structure. Interestingly, TIB-3CPBA-TAPA/γPA6 is found to emit greenish afterglow luminescence that can last for 4 s at room temperature, only under a loading of 0.1 wt% that harvests the UV exposure efficiently. Different from converting non-afterglow γ crystal (γPA) into afterglow α crystal (αPA), our facile strategy achieves longer afterglow with a higher melting point (220°C) and a tripled quantum yield (1.8%). In addition, the viscoelasticity of the polymer melt is improved by TIB-3CPBA-TAPA with a mechanical toughening effect.