ИСТИНА

In this paper, the molecular dynamics method was used to simulate single siloxane dendrimers (from the 2nd to the 8th generation) with the trifunctional Si (CH3) nucleus, the terminal CH3 groups, and two types of trifunctional repeating groups: OSi (CH3) and OSi (CH3) 2 -OSi (CH3). Similar systems have been synthesized recently [1], and their study at the moment is quite relevant. Equilibrium conformations of all molecules were obtained at temperatures from 300 to 600 K. For each system, macroscopic characteristics were calculated for an ensemble of 10 structures obtained independently. The averaging was carried out along equilibrium trajectories at time intervals of up to 2 ns. The effects of temperature on the gyration radius and the shape factor of dendrimers are analyzed. It is shown that the temperature dependence is weak, and that dendrimers are predominantly spherical. The density distributions of all monomer units and individual distributions for silicon atoms of different structural layers of the molecule are obtained. The phenomenon of backfolding of terminal groups was detected and quantitatively evaluated, and the character of the mobility of silicon atoms of different structural layers was studied in details.