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Spontaneous spreading of emulsions on solid surfaces: Morphology and dynamics
Author(s) -
Forester Jonathan E.,
Sunkel Jorge M.,
Berg John C.
Publication year - 2001
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1615
Subject(s) - silicone oil , drop (telecommunication) , materials science , phase (matter) , emulsion , differential interference contrast microscopy , morphology (biology) , silicone , radius , chemical engineering , polymer chemistry , composite material , chemistry , microscopy , optics , organic chemistry , telecommunications , physics , computer security , biology , computer science , engineering , genetics
The spontaneous spreading of emulsions of water dispersed in silicone oil onto glass surfaces is examined using differential interference contrast (DIC) microscopy. Spreading occurs via a precursor film from which the emulsion droplets are excluded. The radius of the interline of the bulk drop is found to vary as (time) 1/10 , as is commonly observed for the spontaneous spreading of pure liquids. The spreading rate constant decreases linearly with the volume percent of the dispersed phase, but drops suddenly to zero at approximately 73% dispersed phase. The width and spreading rate of the precursor film also is found to decrease with dispersed phase concentration. A fingering type of instability is evident at the leading edge of the precursor film, yet has little effect on the spreading rate of either the precursor film or the droplet interline. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1817–1825, 2001