TY  - JOUR
A1  - Hasinovic, H.
A1  - Friberg, S. E.
A1  - Kovach, Ildyko
A1  - Koetz, Joachim
T1  - Destabilization of a dual emulsion to form a Janus emulsion
JF  - Colloid and polymer science : official journal of the Kolloid-Gesellschaft
N2  - A vegetable oil (VO) was added to an emulsion of silicone oil in water (SO/W) with mixing limited to once turning the test tube upside down. Initially, the VO was dispersed into virtually centimeter-sized drops and the emulsion contained effectively no Janus drops, while after 1 h of agitation at a low level to prevent creaming, drops of 50-100-mu m size of the two oils were observed: in addition to an insignificant number of Janus drops. The topology of the latter showed them to emanate from flocculated individual drops of the two oils, but with no discernible effect by the interfacial tension equilibrium on the drop topology. Continued gentle mixing gave increasing fraction of Janus drops of increased size with a topology gradually approaching the one expected from the interfacial equilibrium at the contact line. The spontaneous formation of Janus drops indicated a reduction of the interfacial free energy in the process and the interfacial energy difference between separate and Janus drops was calculated for an appropriate range of interfacial tensions and for all oil fractions. The calculations enabled a distinction of the decrease due to interfacial area changes from the reduction of interfacial tensions per se, with the latter only a minor fraction.
KW  - Emulsion destabilization
KW  - Janus emulsions
KW  - Interfacial equilibrium
KW  - Microfluidics
Y1  - 2014
U6  - https://doi.org/10.1007/s00396-014-3263-3
SN  - 0303-402X
SN  - 1435-1536
VL  - 292
IS  - 9
SP  - 2319
EP  - 2324
PB  - Springer
CY  - New York
ER  -