Solution and rheological properties of cationic cellulose/gemini surfactant: Effect of the alkyl chain and spacer length

In this paper, three sulfonate-containing gemini surfactants, sodium 1,1 ' -(4,4 ' -methylenebis(4,1-phenylene))bis(1-oxooctane-2-sulfonate) (C 8 -M 1 -C 8 ), sodium 1,1 ' -(4,4 ' -(ethane-1,2-diyl)bis(4,1-phenylene))bis(1-oxooctane-2-sulfonate) (C 8 -M 2 -C 8 ), sodium 1,1 ' -(4,4 ' -methylenebis(4,1-phenylene))-bis(1-oxododecane-2-sulfonate) (C 12 -M 2 -C 12 ), were synthesized and characterized with FT-IR, 1 H NMR and MS. Furthermore, interaction between a cationic cellulose-based polyelectrolyte, PQ-10, and gemini surfactants were investigated by surface tension, turbidity, flow and low-amplitude oscillation rheology analysis. For comparing, the interaction of their corresponding monomeric counterpart sodium dodecyl sulfate (SDS), sodium 1-octanesulfate (SOS) was also studied. Results showed that the concentration value at T 1 , defined as critical surface complex concentration, for the PQ-10/surfactant was in order of PQ-10/C 8 -M 2 -C 8 > PQ-10/C 8 -M 1 -C 8 > PQ-10/C 12 -M 2 -C 12 . Precipitation appeared at low concentration for Gemini surfactants than their monomeric counterparts, and for the gemini surfactants with shorter spacer or longer hydrocarbon chain. The increase/decrease of the crossover frequency (ω c ) (the relaxation time, τ c ) for PQ-10/C 12 -M 2 -C 12 indicated the formation/collapse of network structures, while PQ-10/SDS showed no obvious change.