Adjustment and detection of the topology freezing transition temperature of vitrimers based on vitrimers doped with nanoparticles and photonic crystals

Abstract

The topology freezing transition temperature (T_v) of vitrimers is an important indicator for their applications. The T_v of vitrimers could be changed by using chemical methods. Herein, a physical method is proposed to adjust and detect the T_v of vitrimers based on upper vitrimers doped with SiO₂ nanoparticles and lower photonic crystals (PCs) from SiO₂ nanoparticles. When the photonic coatings are heated, the upper vitrimers changed from a viscoelastic-solid state to a viscoelastic-liquid state, and the reflection peak intensities of the PCs increased because light easily penetrated the coatings. The T_v of vitrimers could be determined according to changes in the peak intensities. When the photonic coatings are synthesized at 140 °C for 6 h under 2.6 MPa, the lower PCs exhibited no change, and as the doping amounts of SiO₂ nanoparticles in the upper vitrimers are increased, the T_v of the photonic coatings decreased from 90 °C to 72.5 °C. The photonic coatings have potential applications in adjustment and detection of T_v of other vitrimers, anti-counterfeiting and displays.