Appraisal of surface-active properties and micellization behaviour of imidazolium gemini surfactants

Abstract

ABSTRACT A series of imidazolium gemini surfactants with three different hydrophobic chains have been synthesised and analysed by 1HNMR, 13CNMR, FTIR, ESI-MS and TGA. The conductivity of these surfactants has been taken at 293, 298, 303 and 308 K in water, and results have indicated that these gemini surfactants act as weak electrolytes. Thermodynamic properties calculated from conductance have confirmed that micellization was spontaneous and more favourable in comparison to dissociation process. Density as well as viscosity measurements were indicating that there exist significant interactions between these gemini surfactants and solvent (water) molecules. Surface active properties have confirmed that imidazolium gemini surfactants are excellent candidates to lower the surface tension at air/water interface and having affinity to form aggregates in the bulk solution after CMC. Thermogravimetric analysis (TGA) has indicated that all the three surfactants have thermal stability up to 535–600 °C. The thermal stability was increasing with increasing hydrophobic chain, and the activation energy for thermal decomposition was found in the range of 20.43–36.55 kJ/mol. Moreover, antimicrobial activities were examined and inferred that these compounds exhibit excellent antimicrobial activity against B. cereus and C. albicans.