Thermodynamic Properties of a Fourth-Generation Carbosilane Dendrimer with Terminal Trimethylsilylsiloxane Groups.

The heat capacity–temperature dependence for a fourth-generation carbosilane dendrimer with terminal trimethylsilylsiloxane groups is determined via adiabatic vacuum calorimetry in the 5–344 K range of temperatures and differential scanning calorimetry in the 310–560 K range of temperatures. An anomalous change in the heat capacity of the dendrimers in the range of T = 46–68 K is detected along with a transition in the range of T = 179–196 K, due to its devitrification. The thermodynamic characteristics of the detected transformations are determined and analyzed. The standard thermodynamic functions of the studied dendrimers in the range T → 0 to 560 K and the standard entropy of its formation at T = 298.15 K are calculated using the obtained experimental data. A comparative analysis is performed of the thermodynamic properties of fourth-generation dendrimers that differ in the nature of their molecular skeletons and terminal groups. [ABSTRACT FROM AUTHOR]