Understanding and Prediction of the Clouding Phenomenon by Spontaneous and Effective Packing Concepts

Abstract

AbstractIn this work, we show by which mechanism branching of the hydrocarbon chains influences the cloud point of nonionic, ethoxylated surfactants. The temperature‐induced separation into a dilute and a concentrated liquid phase is of liquid–gas type and can be explained by the relative probability of endcaps and branching points of the cylindrical micelles in both phases. The influence of branches on the hydrocarbon chains can be easily understood by means of spontaneous and effective packing concepts, while quantification via hydrophilic/lipophilic balance (HLB), hydrophilic‐lipophilic difference (HLD), and HLD‐Net Average Curvature requires parametrization. The phase equilibrium above the cloud point phenomenon is equivalent to the Winsor I type phase equilibrium, one of the five known phase equilibria in ternary systems.