Cationic surfactants modulate aqueous micellization and wetting on PTFE by Triton X-100: Effect of alkyl chainlength, headgroup and counterion

Abstract

Micellization of several cationic surfactants in aqueous solution and their adsorption characteristics on polytetrafluoroethylene (PTFE) surface were studied using scattering and wettability methods. The obtained results indicate that the micelle size/shape and wettability depended on the hydrophobicity of alkyl chain and counterion of surfactants. Effect of these cationic surfactants varying in alkyl chain length, polar head groups and counterions on nonionic surfactant Triton X-100 (TX-100) solution behaviour was investigated by cloud point (CP), dynamic light scattering (DLS) and small angle neutron scattering (SANS). TX-100 solutions showed marked increase in CP and progressive decrease in micellar size depending on hydrophobicity of alkyl chain length and counterion, but interestingly different polar head groups demonstrated identical effect on TX-100. However, the solution behaviour of TX-100/cationic surfactant mixed system was different in the presence of salt. The results are discussed considering charged mixed micelle in TX-100-cationic surfactant system, which are highly useful to alter performance based properties of TX-100.