Comparative studies on the stability of emulsions of perfluoroorganic compounds stabilized by pluorosurfactant and block copolymer

Abstract

The stability of emulsions of perfluoroorganic compounds (more than twenty) of various classes has been investigated: polycyclic compounds and their alkyl derivatives, alkyl- and cycloalkylamines, alkyl ethers. Emulsions of perfluoroorganic compounds were prepared on the basis of block copolymer of ethylene oxide and propylene oxide with molecular mass of about 8000 and 80% of oxyethylene moiety in the molecule, and a fluorosurfactant C 6F 13CH 2−SO 2NH(OC 2H 4) 16OH. The stability of emulsion of perfluoroorganic compounds (of the same class) stabilized by the block copolymer has been found to vary linearly with the number of carbon atoms as a plot of 1g K−n c, where K is the constant of enlargement of species obtained as the tangent of the angle formed by a slope of medium-diameter species cube vs. time; n c, the number of carbon atoms in a perfluoroorganic molecule. Emulsions of perfluorinated alkyl ethers and alkylamines have the highest stability, while lowest stability has been observed for polycyclic compounds. For fluorosurfactant-stabilized emulsions, the tendencies of stability variation are similar to those obtained for the block copolymer emulsions. The stability of fluorosurfactant emulsions was higher than that of block copolymer emulsions.