Influence of the oleic phase and co-surfactant addition in non-ionic microemulsified systems

Abstract

Microemulsion is a thermodynamically stable dispersion consisting of an aqueous and an organic phases, both stabilized by surfactant molecules and when in need, co-active surfactant. The nature and structure of these components are essential in the formulation of microemulsified systems. For this, the construction of phase diagrams can be a fundamental tool to characterize the ideal experimental conditions for the existence and operation of microemulsions. Thus, the present work had as objective to obtain a comparison between microemulsions with different compositions through the construction of ternary diagrams, aiming to achieve the most stable system. To produce microemulsified systems, a non-ionic surfactant (Ultranex NP 60), a co-surfactant (Isopropyl Alcohol), two organic phases (pine oil and castor oil) and an aqueous phase (glycerin solution) were used. Also complementing the study, rheological tests of the oleic phases were accomplished, as well as their thermogravimetric analysis. The focus of the reached ternary diagrams was to find the system with the largest Winsor type IV region (microemulsion). It was verified this region had a significant increase by the addition of the co-surfactant in the medium and using a vegetable oil, such as pine oil, since it promotes strong surfactant-oil interactions on the interface.

Obtaining and characterizing microemulsion systems containing Alkali-Surfactant-Polymer (ASP) for advanced oil recovery application

“…Microemulsions are self-aggregated, spontaneous and dynamic systems, with an oil phase and an aqueous phase, stabilized by a surfactant and, if necessary, a co-surfactant. The co-surfactant consists of a short-chain alcohol, such as butan-1-ol, used to act directly on the packaging factor and its function is to reduce the repulsion of the polar "heads" of the surfactants, stabilizing the micelle (Castro Dantas et al, 2017;Garnica et al, 2020;Curbelo et al, 2021). Microemulsions differ from conventional emulsions because they allow the stabilization of immiscible, thermodynamically stable, translucent, isotropic mixtures and have much smaller structural units (Gurgel, 2004;Gradzielski, 2008;Soares, 2011;Viana et al, 2015;Castro Dantas et al, 2019).…”

“…Microemulsions differ from conventional emulsions because they allow the stabilization of immiscible, thermodynamically stable, translucent, isotropic mixtures and have much smaller structural units (Gurgel, 2004;Gradzielski, 2008;Soares, 2011;Viana et al, 2015;Castro Dantas et al, 2019). According to Rossi et al, (2006), Castro Dantas et al (2017 and Curbelo et al (2021), in the microemulsion, with ionic aggregates, the phases are organized similarly to the emulsion. The oil phase is dispersed in the aqueous phase, that is, the hydrophobic part of the molecule is grouped inside the micelle to have a minimum of surface in contact with water, while the polar ends are directed towards the aqueous medium, forming direct microdroplets.…”