BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
X-WR-CALNAME:Anomalously Stable Mixtures of Water and Oil 
X-WR-TIMEZONE:Eastern Time (US & Canada)
BEGIN:VEVENT
DTSTAMP:20260912T223655Z
UID:tag:localist.com\,2008:EventInstance_42534706781841
DTSTART:20230317T160000Z
DTEND:20230317T170000Z
DESCRIPTION:Oil and water do not mix. Upon agitation they do mix\, with one
  phase being dispersed into the other as droplets\, forming an emulsion. H
 owever\, as soon as the agitation is removed coalescence rapidly recombine
 s the dispersed phase and reestablishes the original phase-separated coexi
 stence. Addition of surfactant can delay this recombination and can produc
 e a metastable emulsion. However\, in the absence of some type of surfacta
 nt an emulsion can not exist. Here we report the surprising observation th
 at metastable water-in-oil emulsions can exist\, even at surprisingly larg
 e volume fractions of the dispersed phase. We show that this behavior is t
 he result of an unexpected weak adhesion between droplets due to adsorptio
 n of oil molecules at the interface.  This results in a critical value of 
 the internal pressure that droplets can sustain before coalescing\, manife
 sted by a maximum volume fraction at which a stable emulsion can be produc
 ed. Above\, the emulsion breaks under shear forming double emulsion drople
 ts composed of the primary water-in-oil dispersion with a characteristic i
 nternal volume fraction. These results provide a new understanding of the 
 interactions of oil molecules at the water interface which will allow surf
 actant-free stable emulsions to be produced for a broad range of fluid mix
 tures\; moreover\, this will lead to a new method for formulating material
 s through double emulsions made with a single step.
GEO:42.3783;-71.117081
LOCATION:Pierce Hall\, 209
SUMMARY:Anomalously Stable Mixtures of Water and Oil 
URL;VALUE=URI:https://events.seas.harvard.edu/event/anomalously_stable_mixt
 ures_of_water_and_oil
CATEGORIES:Colloquia / Seminar / Lecture
END:VEVENT
END:VCALENDAR