Self‐Assembly and Adsorption Behavior of Aqueous 1‐Decyl‐3‐Methylimidazolium Chloride in Presence of Sodium Polyacrylate

Studies on the interactions of a surface‐active ionic liquid (SAIL), 1‐decyl‐3‐methylimidazolium chloride (DMImCl), with a polyelectrolyte sodium polyacrylate (NaPAA) have been performed in water by tensiometry, conductometry and DFT approach. Three species comprising the surfactant ( S ) and the polyion ( P ): a surface‐active complex ( PS s ), a bi‐layer complex () which adsorbs only on PS s , and a non‐surface active polyion‐micellar aggregate ( PS M ) along with the surfactant micelles have been shown to be formed. We demonstrate that a stratified surface with multilayer alkyl chains and ionic headgroups adjacent to the vapor‐phase has been formed in DMImCl‐NaPAA solutions prior to the critical micelle concentration ( cmc ). Three different critical concentrations besides cmc have been identified. The geometry of DMImCl‐NaPAA coordinated structure gets more stabilized than that of either of the components. Compared to the polyelectrolyte‐free case, DMImCl micellization becomes thermodynamically less spontaneous with added NaPAA. The micellization has been found to be exothermic driven by entropy. Adsorption deteriorates as temperature rises. DMImCl has been predicted to form spherical micelles in DMImCl‐NaPAA solutions. Influence of polyion charge density on the interfacial and aggregation phenomenon of DMImCl has been discussed to shed light on the nature of interactions in the investigated SAIL‐polyelectrolyte systems.