Interfacial Diffusion Dynamics Of Epoxy Vitrimers

Vitrimer,a kind of crosslinked network with dynamic covalent bonds,which has broad application prospect in self-healing,adhesion,repeatable processing and adaptability.The study of interfacial diffusion dynamics is of great theoretical significance and practical value for understanding the adhesion and self-healing behavior.In this work,the interfacial broadening between epoxy Vitrimers was studied by atomic force microscope nanomechanical measurement(AFM-NM).The results are as follows:(1)The diffusion between Viitrimer and polymethyl methacrylate(PMMA)would form a new transition region,whose composition and micromechanical properties present a certain gradient between two polymers.The interfacial broadening process showed evident temperature dependence in accordance with Arrhenius-like law,but the energy barrier was higher than the transesterification reaction.The diffusion behavior deviated from the first-order reaction kinetics.(2)AFM was used to track the embedding rates of gold nanoparticles on the surface of Vitrimer sample and analyze the relationship between the rates and annealing time and temperature.The embedding process is accelerated with the increase of temperature.It was noted that the embedding rates have a significant temperature dependence when exceeding the topological transition temperature,Tv.However,the activation energy of the particle embedding process was lower than the first-order transesternization reaction kinetics.