Premium
Mechanism of antifoam behavior of solutions of nonionic surfactants above the cloud point
Author(s) -
Chaisalee Ratchadaporn,
Soontravanich Sukkhwan,
Yanumet Nantaya,
Scamehorn John F.
Publication year - 2003
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-003-0280-3
Subject(s) - coacervate , cloud point , defoamer , chemistry , pulmonary surfactant , surface tension , phase (matter) , ethylene oxide , chemical engineering , chromatography , aqueous solution , aqueous two phase system , organic chemistry , thermodynamics , polymer , dispersion (optics) , biochemistry , physics , optics , copolymer , engineering , dispersant
Aqueous solutions of nonionic surfactants exhibit low foaming above their cloud point, a temperature above which the homogeneous solutions separates into two phases: a dilute phase containing a low surfactant concentration and coacervate phase containing a very high surfactant concentration (e.g., 20 wt% surfactant). In this work, foam formation was measured for the dilute phase, the coacervate, and the mixed solution using the Ross‐Miles method for nonylphenol polyethoxylates with 8, 9, or 10 ethylene oxide moieties per molecule. The dilute phase showed no antifoam effect above the cloud point if the coacervate phase was not present, and the coacervate phase foamed little in the absence of the dilute phase. The coacervate phase acts as an oil droplet antifoam to the dilute phase. From surface and interfacial tension data, entering, spreading, and bridging coefficients for this system make it appear probable that the coacervate phase is forming bridges across the film lamellae of the dilute‐phase foam and acting to suppress foam formation through the bridging mechanism.