Grinding-stimulated fluorescence enhancement in carbon nanoparticles/poly(vinyl chloride) composite

The physical damage of engineering materials is challenging to perceive, particularly when they occur with only a slight extent. To present the location of damage to engineering is still difficult to achieve. Mechanical responsive engineering materials are therefore highly desired. Herein, a type of composites comprised of carbon nanoparticles (CNP) and poly(vinyl chloride) (PVC) was prepared via a heating incubation process. Notably, we found that these composites were in a metastable state and exhibited a grinding-stimulated fluorescence enhancement performance. After grinding stimulation, a bright orange-yellow color emission appeared and the fluorescence intensity of the composites exhibited a 75-fold enhancement. It was noted that grinding had no effect on the fluorescence of CNP alone. The fluorescence enhancement may be due to the change in the surface environment of CNP, as grinding facilitates the entry of CNP into PVC. In addition, fluorescence enhancement was also observed in tightening screw experiments using commercialized PVC films, demonstrating the abrasive-stimulated fluorescence enhancement properties of this CNP/PVC. Such remarkable mechanical response property and interesting combination between CNP and PVC will provide avenue to promote the development of smart engineering materials and have considerable potentials in external force response and structure damage surveying.