Interfacial Studies of the Formation of Microemulsions of Water in Carbon Dioxide with Fluorinated Surfactants

Carbon dioxide/water, water/carbon dioxide emulsions and double emulsions stabilized with a nonionic biocompatible surfactant

“…CO 2 phase. At lower CO 2 densities, the solvation strength of CO 2 is weak and the surfactant does not migrate to the CO 2 phase [18,26,27,[30][31][32][33]. It either remains in water or at higher salinities forms a surfactant-rich middle phase.…”

Effect of branching on the interfacial properties of nonionic hydrocarbon surfactants at the air–water and carbon dioxide–water interfaces

“…The interfacial behavior of surfactants at the C-W interface, particularly for conditions most relevant to W/C microemulsions, has already been studied [15,17,25,26,29,30,[34][35][36][37]. The most effective surfactants for microemulsions initially required fluorocarbons or siloxane surfactant tails to achieve ultra low interfacial tension (c) values which were of paramount importance in these systems [38][39][40][41].…”

“…The molecular interactions between the surfactant tail and CO 2 phase, as a function of pressure, can have a large effect on the surfactant partitioning between the CO 2 and water phases [25], the interfacial tension [26], adsorption of the surfactant at the interface [26,27], and thus the structure of the surfactant monolayer [28][29][30]. Phillips and Couchman found that rheological data generated for nitrogen foams was not sufficient to describe the same system with CO 2 foams [31].…”

Synthesis of perfluorinated functionalized, branched ethers

“…The key to designing surfactants that can stabilize water-in-CO 2 microemulsions is to find a suitable ''CO 2 -phillic'' molecular group that provides a steric barrier to aggregation. Preliminary results have shown that the difunctional linear perfluoropolyethers exhibit superior abilities to form water-CO 2 microemulsions [19,20]. The investigations into the branched materials are ongoing.…”