Investigation of the effect of poly (sodium styrene sulfonate) on sodium glycodeoxycholate and sodium tetradecyl sulfate mixed micelle

The interactions of polyelectrolyte poly (sodium styrene sulfonate or NaPSS) and anionic surfactants, sodium glycodeoxycholate (SGDC) and sodium tetradecyl sulfate (STS), as well as their combination (SGDC + STS) at different mole fraction ratios, were investigated using surface tension analysis. In the SGDC + STS binary mixture, when the amount of NaPSS (0.005–0.03%) increased from \({\alpha }_{{\text{SGDC}}}\) 0.0 to 1.0, increasing the critical micellization concentration (cmc) of the mixtures. The minimum cmc values were found from 0.833 to 1.480 mmol L⁻¹ in the presence of 0.03% of NaPSS. Clint, Rubingh, Motomura, and Rodenas approaches were used to evaluate the ideal cmc, activity coefficients (f_i), interaction parameter (–β), micellar compositions (x), and ideal micellar composition of (x^id) of SGDC + STS mixtures. Synergism has been demonstrated by the experimental values of c_0m being lower than the ideal values in water. Moreover, by adding NaPSS from 0.005 to 0.03%, the synergism interaction was eliminated and antagonism behavior was developed. The standard Gibb’s free energy of micellization (\({\Delta G}_{m}^{0})\) and surface excess (Γ) and surface area per absorbed molecules (A_min) was decreased or increased depending on NaPSS amount in the SGDC + STS mixture with varying \({a}_{{\text{SGDC}}}\).