Insight into the Structure of Polybutylcarbosilane Dendrimer Melts via Extensive Molecular Dynamics Simulations

Extensive molecular dynamics simulations of polybutylcarbosilane dendrimer melts were performed in a wide temperature range from 300 to 600 K. The melt macroscopic and structural characteristics were analyzed for the third up to the eighth generation dendrimers for the systems consisting of 8 and 27 dendrimer molecules in the simulation box. For every system, averaging was performed over 8 independent simulation runs and along equilibrium time trajectories of up to 5 ns. Calculated values of the thermal expansion coefficients, heat capacity, and self-diffusion coefficients are in a good agreement with experimental observations. Analysis of the molecular mass dependence of the gyration radius and shape factor, detailed radial density distributions of dendrimer structural units, mobility of the branching points, and intermolecular interaction energy allowed to shed light on the basics of distinction in behavior of low and high generation dendrimer melts and formulate the directions of further research.