A comparison of several samples of modified hydroxyethyl cellulose and their interactions with surfactants

Abstract

We compared the solution behavior and the macroscopic properties of samples of hydroxyethyl cellulose (HEC) which were modified by perfluoroalkyl chains (F-HMHEC), by cationic groups (cat-HEC), and by hydrophobically modified cationic side chains (cat-HMHEC). It is shown that the viscosity increases by hydrophobic and or ionic modification of the HEC, and the entanglement concentration, C*, decreases by hydrophobic substitution of the HEC.

On addition of ionic surfactants the viscosity of the modified HEC solutions increases even more. Solutions with viscoelastic properties and sometimes yield stress values are found for the F-HMHEC samples with anionic and cationic surfactants and the cat-HEC and cat-HMHEC samples with oppositely charged (anionic) surfactants. Interactions between the cat-HMHEC samples and surfactants of the same charge are shown in surface tension measurements. The results of the observed polymer-surfactant-interactions are interpreted in terms of association between the oppositely charged and/or the hydrophobic parts of both components.