Computer simulation of intramolecular mobility of dendrimers

Structure and intramolecular mobility of a carbosilane dendrimer of the 5th generation has been analysed in a wide temperature range by molecular dynamics. It is shown that in a "poor" solvent, the frequency of conformational transitions, f(rot), is independent an the conformer position in the macromolecule with the exception of chain end fragments. For the latter, the frequency was 2-3 times higher at all temperatures. In a "good" solvent, f(rot) uniformly increases with a conformer distance from the centre of the molecule. Intramolecular diffusion of chain ends was highly temperature dependent. This allowed to suggest the existence of "liquid-like" and "glassy" states of individual dendrimer molecules. (C) 1999 Elsevier Science B.V. All rights reserved.