Intrinsic fluorescent phase change materials-based polymer networks: Tuning fluorescence emission intensity and phase change properties for thermal energy storage

Abstract

Polymeric intrinsic fluorescent phase change material (FPCMs) networks will have a great advantage over conventional PCMs for the multi-functionality. In this research, intrinsic FPCMs networks combining fluorescence emission and phase change properties are synthesized in a facile and robust approach by integrating fluorescein and polyethylene glycol at the molecular level. In FPCMs, fluorescein-derived structures serve as the fluorescent emission components and PEG-derived segments work as the latent heat-based thermal energy storage units and the fluorescence intensity regulators. The fluorescence emission intensity of FPCMs obviously decreases by an order of magnitude during a phase change process from 40 °C to 60 °C, which is denoted as phase change-induced fluorescence emission effect in this report. FPCMs possess the high latent heat up to 116.1 J/g, the shape stability even at 150 °C, the high thermal reliability and stability. FPCMs can be prepared by both catalyst-free and catalyst-accelerated process to meet different production requirements. The combination of phase change and fluorescence emission properties in the crosslinking network structure will endow FPCMs with potential application abilities in smart energy-storage fluorescent devices etc.