Langmuir behaviors of the complex of anionic and cationic surfactant at the air/water interface

The complexes of anionic and cationic surfactant were prepared by mixing a cationic surfactant (cetylpyridinium chloride (CPCl, C16) with anionic surfactant ((sodium octyl sulfonate (OSS, C8), sodium dodecyl sulfate (SDS, C12), sodium tetradecyl sulfonate (TDSS, C14), sodium dodecyl benzene sulfonate (SDBS, C12)) having different alkyl chain lengths in 0.15 M NaCl aqueous solution. The behaviors of precipitates at the air/water interface were studied by surface-pressure–area isotherm, surface potential and Brewster angle microscopy (BAM), respectively.