Investigation of the polymer additive on the lyotropic lamellar phase formed by surfactants with different head groups

Abstract

In this study, the effect of polyvinylpyrrolidone (PVP) polymer on lyotropic lamellar phases obtained using different types of surfactants, anionic and cationic, was compared. Three different methods were used to make these comparisons. The polarized microscope (POM) method was used to observe and compare morphological changes. It was observed that the texture structures of the lyotropic lamellar phases obtained by using anionic and cationic surfactants were different from each other. Structural changes were investigated by the small-angle X-ray scattering (SAXS) method. As the polymer concentration added to the lyotropic lamellar phase(s) increased, it was determined that the structural changes of the anionic and cationic samples were different from each other. While the polymer added to the anionic surfactant compresses the structure, the polymer added to the cationic surfactant does not significantly alter the structural parameters. The interactions of surfactant-polymer molecules with each other and their packaging were accordingly investigated by Fourier transform infrared spectroscopy (FTIR). How the polymer was added to the lyotropic lamellar phase and how the surfactant interacted with the chain and head groups was determined by examining the frequency shifts of the methylene chains and head groups. These frequency shifts provide information about trans-gauche transformations. The results indicate that the polymer added to both groups leads to a transition towards a gauche conformation. Both polymers and lyotropic lamellar phases have wide biological and technological uses. For this reason, their use together, that is, the interactions of polymer doped-lamellar phases, is interesting and should be understood.

Graphical Abstract