De-gassed water and surfactant-free emulsions: history, controversy, and possible applications.
Recent reports claiming stabilisation of surfactant-free oil-in-water emulsions (o/w SFEM's) have intrigued the colloid science community, and been reported in both the scientific literature and popular press. Key to the formation of SFEM's is a sequence of solidification by freeze quenching, degassing by action of vacuum, then thawing, known as freeze-pump-thaw (F-P-T). It is believed that the "emulsification" is caused by a reduction of hydrophobic interactions owing removal of dissolved gas after these F-P-T cycles. This review summarises literature on SFEM's, covering experiments, proposed mechanisms, and some potentially exciting applications.
Eastoe
Julian
J
School of Chemistry, University of Bristol, Bristol BS8 1TS, UK. julian.eastoe@bris.ac.uk
Ellis
Christopher
C