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7956769 
Journal Article 
WATER CYCLOHEXANE SPAN 80 TWEEN 80 SYSTEMS - SOLUTION PROPERTIES AND WATER OIL EMULSION FORMATION 
Davies, R; Graham, DE; Vincent, B 
1987 
Yes 
Journal of Colloid and Interface Science
ISSN: 0021-9797
EISSN: 1095-7103 
116 
1 
88-99 
English 
WOS:A1987G525500012 
The solution properties of sorbitan monooleate (Span 80) and ethoxylated sorbitan monooleate (Tween 80) in cyclohexane are discussed. It is shown that aggregates of nominal "radius" ∼65 nm are formed in the former case at concentrations up to ∼0.5 mole dm-3. The aggregation behavior is very sensitive to the presence of water. On the other hand, the Tween 80 + cyclohexane system shows phase separation behavior. At ambient temperature a two-phase (initially turbid) region appears at very low Tween 80 concentrations returning to single phase at higher concentrations. Lamellar-type structures form in the two-phase region while spherical aggregates (radius < 100 nm) seem to form in the single-phase region. With (approximately) equimolar mixtures of Span 80 and Tween 80 in cyclohexane, small spherical micelles (∼7-nm radius) are formed. The addition of water to Span 80 (HLB 4.3) did not lead to useful W O emulsions, but addition of water (or NaCl solution) to equimolar solutions of Span 80 and Tween 80 did, at least over the water volume fraction range ∼1-5%. These droplets were reasonably monodisperse (in the range 30-100 nm), but an unexpected feature was that their mean radius decreased with increasing aqueous phase volume fraction. 1987.