Interaction between poly (ethyleneglycol) and dioctadecyldimethyilammonium and diododecyldimethylammonium bromide in aqueous solution / Interação de poli(etileno glicol) com brometo de dioctadecildimetilamônio e didodecildimetilamônio em dispersões aquosas

ABSTRACT

Poly (ethyleneglycol) (PEG) is a water soluble neutral polymer, and dioctadecyldimethylammonium (DODAB) and diododecyldimethylammonium (DDAB) bromide are double chain cationic surfactants derived from the quaternary ammonium that have been widely investigated due to their high application potential in different areas of the science and technology. The physical properties of PEG, DODAB and DDAB in aqueous solution are well-known. However, the properties of mixtures of the polymer with those surfactants are not. We investigated the interaction of PEG with DODAB and DDAB in aqueous solution, within a range of total concentration of the components of 0-1 wt%, and the phase diagrams built up, with special interest for the vesicular phases. We used PEG with molecular mass between 200Da and 2 MDa and the phase diagrams were built up at 25C, that is, above the melting temperature (Tm) of DDAB (Tm = 16C) and below Tm of DODAB (Tm = 45C). DODAB and DDAB have the common characteristic of forming unilamellar vesicles at low surfactant concentrations and umultilamellar vesicles at higher concentrations; at intermediate concentrations, uni- and multilamellar vesicles coexist in solution. The borders of these different vesicle phases are not well defined. We observed in this Thesis that the effect of PEG on the structures of DODAB and DDAB aggregates in water depends on the molecular mass

RESUMO

Apresenta resumo em inglês.