Aqueous behaviour of cationic surfactants containing a cleavable group

The aggregation behaviour of two novel cationic RAFIF agents (transfer surfactants); N,N-dimethyl-N-(4-(((phenylcarbonothioyl)thio)methyl)-benzyl)ethanammonium bromide (PCDBAB) and N-(4-((((dodecylthio)-carbonothioyl)thio)methyl)benzyl)-N,N-dimethylethanammonium bromide (DCTBAB) in diluted solutions have been investigated by surface tension, conductimetry and microcalorimetry measurements. The thermodynamic parameters i.e. the critical micelle concentration (cmc), the degree of micelle ionization (alpha), the head group surface area (a(0)), Delta H-mic, Delta G(mic) and T Delta S-mic are reported at 303 K. The thermodynamic parameters have been compared to those of the conventional surfactant cetyltrimethylammonium bromide (CTAB) in order to specify structural relationships. The obtained results have been discussed considering the hydrophobic behaviour of the S-C=S- linkage and the specific interactions that arise from the introduction of the benzene ring into the hydrophobic part., (C) 2008 Elsevier Inc. All rights reserved.