Thermodynamics of flow and vaporization processes in long-chain liquids

The flow and vaporization behaviors of long-chain esters of varying molecular weights (300-900) and branching (linear, Y -shaped, and + -shaped molecules) have been studied. The flow behavior is found to depend on the structure as well as the molecular weight. Below a molecular weight of 600, the molecules flow wholly but above this, segmental motion occurs, and the flow becomes independent of the molecular weight which is explained from the blob model. The blob concept demonstrates that the hole of a size of about 11 Å is needed for the flow to occur and it is much less than the size of the molecule