Mixed surfactant system SANS spectrum modelisation

Abstract

In this work, small angle neutrons scattering (SANS) was exploited to investigate the inner structure of a mixed system containing a
nonionic fluorosurfactant (undecafluoro-n-pentyl-decaoxyethylene ether (C5F11(EO)10; FSO100) and 66% of a cationic surfactant
dodecyltrimethyl ammonium bromide (DTAB) on a wide range of spatial resolution, at 25 °C . The data analysis of the corrected and
normalized scattered intensities was based on the coexistence of two micellar populations, namely, homogeneous polydisperse spheres
and stacked core–shell
disc-like micelles. This fitting model was used assuming either a mixed micellization or a F/H segregation
phenomena. The obtained results support to some degree the micellar mixing but do not exclude completely the occurrence of an intra-
or extra-micellar segregation. A predictive stacking parameter calculated for the mixed system indicates a morphologic transformation
with regards to the pure surfactants.