Latexes formed by rapid expansion of polymer/CO2 suspensions into water. 1. Hydrophilic surfactant in supercritical CO2

Rapid expansion of poly(2-ethylhexyl acrylate) suspensions in supercritical CO2 containing a hydrophilic as well as a CO2-philic surfactant produced s table aqueous latexes. The hydrophilic surfactants were soluble in both CO2 and water. The aqueous latexes could also be formed after depressurization and resuspension of the polymer dispersion in CO2. Latexes in basic buffer solutions were stable for a few weeks for concentrations up to 15.6% and f or several months after sonication. The synthesis of water-dispersible poly mer particles in CO2, which may be transferred to water without the need fo r organic solvents, offers the possibility of new environmentally benign co atings and adhesives.