Paving the Way to Simulate and Understand the Radiochemical Damage of Porous Polymer Foam

The widespread and advanced application of polymers outshines the current ability to theoretically predict their radiation deterioration without much prior knowledge. This work presents a versatile methodology to simulate and forecast the radiochemical damage of polydimethylsiloxane (PDMS) foam. The radiolytic kinetics of PDMS foam in radiation-thermal environments is first studied by multiscale simulations with experimental verification. Then the radiolytic kinetic model of PDMS is developed via material informatics gained from experiments, reactive force field simulations, and density functional theory calculations, involving the paramount elementary reactions and other events in the physical, physicochemical, and chemical stages. The model configuration is designed to interactively couple with the service conditions and structural relationships, which enables the model to allow for the intricate radiation-thermal coupling effect, dose rate effect, and postradiation effect. To improve the adaptivity and accuracy of the model and further rationalize the radiolytic kinetics frame, the diffusion coefficients and reaction rate constants with temperature, topology, and morphology dependence are calculated. The developed radiolytic kinetic model can precisely predict the deteriorated PDMS system from various aspects simultaneously, including gas yields, radiation chemical yields, and damaged molecular structure and cross-linking network. The overall accuracy in view of the standard deviation calculated from the normalized data is less than 0.35. The proposed methodology has a promising future in nonempirical simulations, multiscale understanding, and goal-oriented harnessing of the structure–property relationships of polymers.