Conformational mobility of carbosilane dendrimer: Molecular dynamics simulation

Abstract

Molecular dynamic simulations were carried out for carbosilane dendrimers of the 5th generation immersed in CCl₄ solvent at different temperatures. The calculations were accomplished by using the AMBER force field in the united atom approximation. Lennard-Jones particles were considered as the solvent molecules with potential parameters corresponding to CCl₄. There was one molecule of a dendrimer in each calculation cell, and the cell's size was large enough to exclude any interaction between dendrimers. The internal structure of the dendrimer (density distributions for both dendrimer and solvent atoms) as well as dynamics of trans–gauche transitions of single bonds and fluctuations of branching points were analysed. It was shown that the one barrier mechanism of conformational transitions observed earlier in linear polymers occurs to be valid also for the conformational rearrangements in dendrimers with the hindered rotation around chain bonds. The contribution of rotational restrictions is essential only for branching points, which are close to the core.