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

•Interaction between PQ-10 and different gemini surfactant was first reported.•The effect of the structure of gemini surfactants on interaction were first investigated.•The experimental data and theoretical model is correlated. In this paper, three sulfonate-containing gemini surfactants, sodium 1,1'-(4,4'-methylenebis(4,1-phenylene))bis(1-oxooctane-2-sulfonate) (C8-M1-C8), sodium 1,1'-(4,4'-(ethane-1,2-diyl)bis(4,1-phenylene))bis(1-oxooctane-2-sulfonate) (C8-M2-C8), sodium 1,1'-(4,4'-methylenebis(4,1-phenylene))-bis(1-oxododecane-2-sulfonate) (C12-M2-C12), were synthesized and characterized with FT-IR, 1H 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 T1, defined as critical surface complex concentration, for the PQ-10/surfactant was in order of PQ-10/C8-M2-C8> PQ-10/C8-M1-C8 > PQ-10/C12-M2-C12. 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 (ωc) (the relaxation time, τc) for PQ-10/C12-M2-C12 indicated the formation/collapse of network structures, while PQ-10/SDS showed no obvious change.