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Desorption behavior of surfactant mixtures at the alumina-water interface

Journal Article · · Journal of Colloid and Interface Science
; ;  [1]
  1. Columbia Univ., New York, NY (United States). Langmuir Center for Colloids and Interfaces
The desorption behavior of cationic-nonionic surfactant mixtures, tetradecyltrimethylammonium chloride (TTAC) and pentadecylethoxylated nonyl phenol (NP-15), at the alumina-water interface was studied. It has been found that while nonionic NP-15 itself does not adsorbed at alumina-water interface, it will do so with cationic TTAC preadsorbed at the interface. During the desorption process, however, the presence of NP-15 in the system was discovered to cause desorption of TTAC. This is attributed to changes in equilibrium among surfactant monomers, mixed micelles, hemimicelles, and solloids upon the addition of NP-15: the cationic TTAC species at the interface is solubilized in NP-15 rich micelles in the bulk and perturb the equilibrium. This in turn is proposed to cause the desorption of NP-15 significant. The desorption behavior in the mixed surfactant system depends on the mixing ratio of surfactants in the mixtures. In nonionic NP-15 rich mixtures, negative hysteresis is observed for the desorption of both TTAC and NP-15. In cationic TTAC rich mixtures, the effect of NP-15 on the desorption of TTAC is limited and the desorption of TTAC is similar to that in single TTAC system; in this case some positive hysteresis is observed for both TTAC and NP-15.
Sponsoring Organization:
National Science Foundation, Washington, DC (United States); USDOE, Washington, DC (United States)
DOE Contract Number:
AC22-92BC14884
OSTI ID:
533090
Journal Information:
Journal of Colloid and Interface Science, Journal Name: Journal of Colloid and Interface Science Journal Issue: 1 Vol. 192; ISSN 0021-9797; ISSN JCISA5
Country of Publication:
United States
Language:
English