Temperature dependent micellization behavior of as synthesized anionic SAILs in aqueous nonionic polymer solutions: conductivity, UV-visible probe and antimicrobial studies

Abstract

As synthesized surface active ionic liquids (SAILs), Tetrapropylammonium Dodecylsulfate (TPADS), and Tetrabutylammonium Dodecylsulfate (TBADS) have been characterized by FTIR, 1H-NMR and 13C-NMR spectroscopic techniques. Conductometric and UV-Visible probe investigations have been attempted to study the aggregation behavior of these synthesized SAILs in aqueous solution of polymers Polyvinylpyrrolidone (PVP) and Polyethylene glycol (PEG) at different temperatures and concentrations. Two breaking points were identified from κ vs [SAILs] plots. First, the critical aggregation concentration (CAC) is recognized with the polymer-SAILs binding and the second being regarded as critical micellar concentration (CMC), suggested to represent saturation point for Polymer-SAIL aggregation. Thermodynamic parameters of micellization ( Δ G m o , Δ H m o and Δ S m o ) are rationalized in terms of interactions prevailing between hydrophobic and hydrophilic regions of SAIL-Polymer system. Micellization process for the blend of SAIL-PVP is found to be more favored than SAIL-PEG at all temperatures. Further, the effect of PVP on the antimicrobial activities of TPADS/TBADS has been tested by measuring zone of inhibition which accounts for higher effectiveness of PVP-SAILs system against gram positive bacteria (Bacillus cereus and Staphylococcus aureus) as compared to gram negative bacteria (Pseudomonas aeruginosa).