Study of Phase Behavior and Interfacial Wetting Behavior for Binary Mixtures by Using Density Functional Theory
Date Issued
2010
Date
2010
Author(s)
Chen, Chia-Ming
Abstract
A density functional theory is incorporated with the statistical associating fluid theory and interaction-site model to investigate the effect of hydrophobic chain length
of amphiphile and interaction energy including hydrogen bonding strength on phase and interfacial wetting behaviors of binary water + amphiphile mixtures. The hydrogen bonding interaction between water and amphiphile is imitated by
temperature-dependent energy parameter according to specific orientation. The phase behavior of this binary mixture would fall into type I, II, III, V, and VI of the
classification scheme of van Konynenburg and Scott by varying the hydrogen bonding strength and the energy parameters. Consider a system of three fluid phases,
α, β, and γ in equilibrium, the wetting behavior of the middle β phase can be easily realized by the contact angle θ spanned by the α-β and the β-γ interfaces for the
droplet of the middle β phase, such as nonwetting, partial wetting, and complete wetting. The transition from a partial wetting to a complete wetting (or nonwetting),
or vice versa, is called a wetting transition. The interfacial wetting behavior and wetting transition in the three-phase-coexisting regions of these binary mixtures are
carefully examined. The global phase diagram and wetting behavior are carefully delineated and systematically discussed by scanning the energy parameter space for
the binary water + amphiphile mixtures with four different hydrophobic chain lengths of amphiphile. Lamellar phase can be observed at low temperatures close to its lower
critical end point in these binary systems with certain chain length of amphiphile. There exists no lamellar phase in the water + amphiphile system when the hydrophobic chain length of amphiphile is too short.
Subjects
density functional
phase behavior
wetting behavior
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-D92524016-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):9bae1b3be5e447a51d58f1a36c82fd17