[EN]Fluorescence probing and -potential measurements have been used to characterize the interactions
in bulk between the zwitterionic surfactant 3-[(3-cholamidopropyl)-dimethyl-ammonium]-
1-propanesulphonate, CHAPS and the polymer polyethylene imine, PEI. Results show that the
strongest attractive interactions are produced between the surfactant and the neutral form of the
polymer PEI. Because the zwitterionic surfactant CHAPS has been proposed as component of
biosensors, we are interested to study the effect of the polymer on CHAPS films, therefore we
transfer the surfactant and PEI/CHAPS mixtures from the solution onto mica by using the Langmuir-
Schaefer and dipping methodologies. The morphology of films is analyzed by means of Atomic force
microscopy, AFM, Optical microscopy and Micro-Raman spectroscopy. The hydrodynamic flow of
water after its evaporation induces the formation of ring-based structures not available to fabricate
devices. This process predominates when materials are transferred from the solution onto mica by
dipping. In contrast, the Langmuir-Schaefer films consist of spherical aggregates and the densest
and the most ordered films were obtained by transferring the PEI/CHAPS mixture of surfactant
concentration above the CMC.
