Solution behavior of anionic polymer sodium carboxymethylcellulose (NaCMC) in presence of cationic gemini/conventional surfactants

The interaction of sodium carboxymethylcellulose (NaCMC) and cationic gemini surfactants (16-s-16, s = 5, 6)/conventional surfactant (CTAB) in aqueous solutions is investigated by conductivity, fluorescence and viscosity techniques. Electrostatic and hydrophobic interactions play a dominant role in such systems. The conductivity results showed that the geminis interact strongly with NaCMC as compared to CTAB. Fluorescence measurements were used to calculate aggregation number for the three combinations which were found about the same as those for the corresponding free micelles. Addition of surfactants leads to an increase in relative viscosity after certain concentration of the surfactants. Further increase in relative viscosity is significant in case of geminis and this increase is ascribed to the physical cross-linking of surfactant micelles with NaCMC chains.

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► The cmc values for geminis are 10–14 times smaller than of CTAB.
► The order of interaction of the surfactants 16-5-16 > 16-6-16 > CTAB.
► The Nagg in presence of NaCMC is the same as those for the corresponding free micelles (conventional as well as geminis).
► Increase in relative viscosity is more for gemini surfactant with shorter spacer.