Complexation of ionic substances with surfactants for solubilisation in supercritical carbon dioxide

Solubilisation of ionic substances in supercritical carbon dioxide has been investigated by making complexes of the ionic substances with specific surfactants that have an affinity for carbon dioxide. Three kinds of water-soluble dyes were used as examples of ionic substances; for the complexation of water-soluble dyes, two kinds of fluorinated surfactants and one kind of polyethyleneglycol surfactant were used. Water-soluble dyes that had been complexed with a suitable surfactant were each solubilised in supercritical carbon dioxide although their solubility was quite different. The contents of dyes and surfactants in complexes also had a significant influence on their solubility in supercritical carbon dioxide.