Phase Behavior and Thermodynamic Phenomena of Hyperbranched Polymer Solutions

Abstract

The understanding of the phase behavior of dendritic polymers, i.e., hyperbranched polymers and dendrimers, is still in its infancy. No systematic thermodynamic investigations on the phase behavior of dendritic polymer solutions have been reported so far. Therefore, this experimental study focuses on the low- and high-pressure phase behavior of hyperbranched polymer−solvent and hyperbranched polymer−solvent−supercritical gas systems. The influence of the solvent polarity, the nature and number of polymer functionalities, and the degree of polymer branching, as well as the polymer and supercritical gas concentration on the phase behavior of selected hyperbranched polymer solutions, is discussed. Thermodynamic phenomena such as the merging of the upper critical solution temperature (UCST) and the lower critical solution temperature (LCST) curves, the pH dependence of the polymer solubility and a remarkably distinct solutropic phase behavior are presented.