Over the past decade there has been much interest in near-critical flu
ids (NCFs) as a 'new' apolar solvent medium. A more recent development
of these studies concerns formation of water-in-NCF microemulsions. T
his has been stimulated both by fundamental interest in surfactant-oil
interactions and by potential applications. A major advance in the pe
riod under review is the formation of stable microemulsions in NCF CO2
without the use of cosurfactant.