Measuring Surface Relaxation of Vitrimers
Chang Liu, Dong Wang
Abstract
We used atomic force microscopy (AFM) to investigate the change of the surface roughness of an artificially rough epoxy-based vitrimer surface as a function of annealing temperatures. The results show that the asperities of the rough vitrimer surface partially relax at temperatures well below the bulk topology freezing transition temperature, Tv, an important technological temperature for vitrimers, where the bond exchange reactions slow down markedly. The estimated surface activation energy for bond exchange reactions, Ea, is much lower than that of the bulk. The results suggest that a layer with enhanced bond exchange reactions or a decreased Tv may exist at the surface of vitrimers, which should have important implications for self-healing, welding, and other applications involving surface properties of the vitrimers.