Rheological Study of Interactions between Anionic Guar and Oppositely Charged Surfactant

Abstract

We have studied the interactions between anionic carboxymethyl guar (CMG) and oppositely charged surfactant: dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), cetyltrimethylammonium bromide (CTAB), and gemini surfactants (16-4-16), using rheological measurements. In the present study, two competing forces, electrostatic interaction and hydrophobic interaction, have been identified as important factors. Various types of structure formed on the anionic CMG chains are qualitatively discussed in comparison. For example, C12TAB and gemini surfactant tend to form polymer-bound aggregates, whereas the C16TAB tend to form the polymer-associated architecture. Furthermore, possible mechanisms based on the experimental results to elucidate these interesting phenomena have been proposed and discussed.