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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2008-6-11
pubmed:abstractText
A simple low-energy two-step dilution process has been applied in oil/surfactant/water systems with pentaoxyethylene lauryl ether (C12E5), dodecyldimethylammonium bromide, sodium bis(2-ethylhexyl)sulfosuccinate, sodium n-dodecyl sulfate-pentanol, and hexadecyltrimethylammonium bromide-pentanol. Appropriate formulations were chosen for the concentrate to be diluted with water to generate oil-in-water (O/W) emulsions or nanoemulsions. For the system of decane/C12E5/water, bluish, transparent nanoemulsions having droplet radii of the order of 15 nm were formed, only when the initial concentrate was a bicontinuous microemulsion, whereas opaque emulsions were generated if the concentrate began in an emulsion-phase region. Nanoemulsions generated in the system decane/C12E5/water have been investigated both by dynamic light scattering (DLS) and contrast-variation small-angle neutron scattering (SANS). The SANS profiles show that nanodroplets exist as spherical core-shell (decane-C12E5) particles, which suffer essentially no structural change on dilution with water, at least for volume fractions phi down to 0.060. These results suggest that the nanoemulsion droplet structure is mainly controlled by the phase behavior of the initial concentrate and is largely independent of dilution. A discrepancy between apparent nanoemulsion droplet sizes was observed by comparing DLS and SANS data, which is consistent with long-range droplet interactions occurring outside of the SANS sensitivity range. These combined phase behavior, SANS, and DLS results suggest a different reason for the stability/instability of nanoemulsions compared with earlier studies, and here it is proposed that a general mechanism for nanoemulsion formation is homogeneous nucleation of oil droplets during the emulsification.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jun
pubmed:issn
0743-7463
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6092-9
pubmed:year
2008
pubmed:articleTitle
Nanoemulsions prepared by a two-step low-energy process.
pubmed:affiliation
College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China.
pubmed:publicationType
Journal Article