“…This behavior clearly differs from that of the Frumkin isotherm (Figure ). The shape of the curves in Figures and for ω 1 > 2ω 2 resembles experimental results shown in some papers of Lunkenheimer. ,, In contrast, for ω 1 ≈ ω 2 an increase of α decreases Π (Figure ), which would simulate the effect of a negative value of the interaction parameter a F in (29) and (30). 3 Π( c )-dependencies calculated from (27) from ω 1 = 200 Å 2 /molecule, ω 2 = 50 Å 2 /molecule, and different α; α = 0 (○), α = 1 (□), α = 2 (▵); bold line, Langmuir isotherm. 4 Π( c )-dependencies calculated from (27) for ω 1 = 70 Å 2 /molecule, ω 2 = 50 Å 2 /molecule, and different α: α = 0 (○), α = 1 (□), α = 2 (▵); bold line, Langmuir isotherm…”
Section: Discussionsupporting
confidence: 71%
“…The shape of the curves in Figures 2 and 3 for ω 1 > 2ω 2 resembles experimental results shown in some papers of Lunkenheimer. 24,32,33 In contrast, for ω 1 ≈ ω 2 an increase of R decreases Π (Figure 4), which would simulate the effect of a negative value of the interaction parameter a F in (29) and (30).…”
An adsorption model is proposed which assumes a different partial
molar surface ω for adsorbed molecules
depending on the degree of saturation of the adsorption layer.
Equations for an adsorption isotherm and a
surface tension isotherm are derived for the adsorption of one single
surfactant or of a mixture of surfactants.
The model assumes that the molecules may adsorb in two different
states, i.e. a large ω at smaller surface
pressures Π and a smaller ω at large surface pressures Π.
Adsorption data of
(N-n-hexadecyl-N,N-dimethylammonio)acetic acid bromide at the air/solution interface
are used to demonstrate the application of
the theory. The experimental results are in very good agreement
with the model.
“…This behavior clearly differs from that of the Frumkin isotherm (Figure ). The shape of the curves in Figures and for ω 1 > 2ω 2 resembles experimental results shown in some papers of Lunkenheimer. ,, In contrast, for ω 1 ≈ ω 2 an increase of α decreases Π (Figure ), which would simulate the effect of a negative value of the interaction parameter a F in (29) and (30). 3 Π( c )-dependencies calculated from (27) from ω 1 = 200 Å 2 /molecule, ω 2 = 50 Å 2 /molecule, and different α; α = 0 (○), α = 1 (□), α = 2 (▵); bold line, Langmuir isotherm. 4 Π( c )-dependencies calculated from (27) for ω 1 = 70 Å 2 /molecule, ω 2 = 50 Å 2 /molecule, and different α: α = 0 (○), α = 1 (□), α = 2 (▵); bold line, Langmuir isotherm…”
Section: Discussionsupporting
confidence: 71%
“…The shape of the curves in Figures 2 and 3 for ω 1 > 2ω 2 resembles experimental results shown in some papers of Lunkenheimer. 24,32,33 In contrast, for ω 1 ≈ ω 2 an increase of R decreases Π (Figure 4), which would simulate the effect of a negative value of the interaction parameter a F in (29) and (30).…”
An adsorption model is proposed which assumes a different partial
molar surface ω for adsorbed molecules
depending on the degree of saturation of the adsorption layer.
Equations for an adsorption isotherm and a
surface tension isotherm are derived for the adsorption of one single
surfactant or of a mixture of surfactants.
The model assumes that the molecules may adsorb in two different
states, i.e. a large ω at smaller surface
pressures Π and a smaller ω at large surface pressures Π.
Adsorption data of
(N-n-hexadecyl-N,N-dimethylammonio)acetic acid bromide at the air/solution interface
are used to demonstrate the application of
the theory. The experimental results are in very good agreement
with the model.
“…We have detected alternation effects in the adsorption properties of amphiphiles of different chemical structures like standard free energy of adsorption, saturation adsorption (limiting surface area demand per molecule adsorbed), and surface interaction parameter only recently. − ,, …”
Section: Resultsmentioning
confidence: 99%
“…[23][24][25] We have detected alternation effects in the adsorption properties of amphiphiles of different chemical structures like standard free energy of adsorption, saturation adsorption (limiting surface area demand per molecule adsorbed), and surface interaction parameter only recently. [9][10][11]26,27 So far a real theoretical explanation of the effects of alternation in the adsorption parameters is still missing. There are two hypotheses worth considering.…”
“…In fact, we observed this phenomenon for non-ionic (18,31) and ionic (8,19,33) amphiphiles at the air/water as well as at the oil/water (33) interfaces with respect to alternation of the number of the hydrocarbon chain length of the surfactant and of the solvent n-alkanes. We also found even/odd effects for surfactants when the number of their propylene oxide (34) and/or ethylene oxide units (35) was successively increased. Even n-alkane/water interfacial tension values revealed an effect of alternation when surface-chemical purity was guaranteed for the different n-alkane/water interfaces (33,36).…”
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