Molecular dynamics simulation for damping properties of PDMS composite enhanced by the last generation siloxane dendrimer alcohol with hydroxyl terminal groups

Abstract

In this study, the damping properties of PDMS composite enhanced by last generation siloxane dendrimer alcohol with hydroxyl terminal groups G3-OH were evaluated by all atomic molecular dynamics simulation (AAMDS) method in terms of damping loss factors (DLFs) tanδ, compositional miscibility (|δi−δ0|), cohesive energy density (CED), binding energy (EB) and maximum free volume fraction (FFVmax). Based on the total atomic charge distribution, further, the potential damping mechanism in composite PDMS/G3-OH(100/47) was explored. The simulation results showed that the |δi−δ0| of composite PDMS/G3-OH(100/47) was 0.0939 (J/cm3)0.5, whose good compatibility between the two components laid a solid foundation for the excellent damping performance. As the argument, the tanδ, CED, EB and FFVmax of composite PDMS/G3-OH(100/47) were 0.8073, 1.668 (J/m3)×108, −19877.607 kcal/mol as well as 39.85 % respectively, which were better than 1.2439, 1.390 (J/m3)×108, −14539.327 kcal/mol and 40.71 % of pure PDMS matrix material PDMS/G3-OH(100/0). Furthermore, the multiple hydrogen bond mechanism can perfectly explain the structure-activity relationship between the internal structure and the excellent damping properties of composite PDMS/G3-OH(100/47). Specifically, a total of 19 α-type hydrogen bonds were formed in the composite PDMS/G3-OH(100/47). All in all, according to the evaluation of AAMDS method, the PDMS composite enhanced by 47-equivalent last generation siloxane dendrimer alcohol with hydroxyl terminal groups G3-OH had outstanding damping properties.