Aggregation properties and toxicity of newly synthesized thiazolium based surfactants – Thermodynamic and computational study

Highlights: • Agregation behavior of two newly synthesized thiazolium salts are studied. • Introduction of –CH₃ on thiazolium ring increase thermal stability and decrease CMC. • Micelle formation reduces the toxicity of salts. • Additional methylation also reduces toxicity. -- Abstract: Two new thiazolium-based surfactants namely N-dodecylthiazolium bromide, [NddTz][Br] and N-dodecyl-4-methylthiazolium bromide, [4mNddTz][Br], were synthesized and investigated as new surface active and antimicrobial agents. Their thermal stability is determined by TG/DSC measurements, and the self-assembly behaviour in aqueous solutions systematically studied applying experimental and molecular dynamics (MD) approach. Obtained results of surface tension and electrical conductivity showed that both newly synthesized salts possess a similar surface activity in aqueous solutions compared to imidazolium-based surface active N-dodecyl-3-methylimidazolium bromide, [NddmIm][Br], ionic liquid. Also, thermodynamic parameters of micellization are calculated and compared with the results obtained by volumetric measurements. Antimicrobial activity of these salts is tested by microdilution method on Gram-positive and Gram-negative bacteria and yeasts. In vitro cytotoxicity study has been performed using human fetal lung fibroblasts (MRC-5) and colon adenocarcinoma (HT-29) cell line.