Monolayers of mono- and dioxyethylene dodecyl ethers at air–water and alkane–water interfaces

1985 ◽  
Vol 63 (10) ◽  
pp. 2742-2746 ◽  
Author(s):  
Robert Aveyard ◽  
Neil Carr ◽  
Helen Slezok
Keyword(s):  
Free Energy ◽  
Surface Pressure ◽  
Water Surface ◽  
Standard Free Energy ◽  
Water Interface ◽  
Straight Chain ◽  
Free Energy Of Adsorption ◽  
Negative Contribution ◽  
Pressure Area ◽  
Hydrophobic Nature

Surface pressure–area isotherms have been obtained for mono- and dioxyethylene dodecyl ethers both spread at the air–water surface and adsorbed at the heptane–water interface and results are compared with those for straight chain alkanols. At the heptane–water interface it appears that the ethyleneoxy groups are disposed parallel to the interface in fairly dilute films. The dual hydrophilic/hydrophobic nature of isolated CH2CH2O groups is demonstrated by showing that they give a negative contribution to the standard free energy of adsorption from both water and heptane to the heptane–water interface.

scholarly journals Adsorption Properties of Hydrocarbon and Fluorocarbon Surfactants Ternary Mixture at the Water-Air Interface

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4313
Author(s):  
Bronisław Jańczuk ◽  
Katarzyna Szymczyk ◽  
Anna Zdziennicka
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Standard Free Energy ◽  
Ternary Mixtures ◽  
Free Energy Of Adsorption ◽  
Interface Tension ◽  
Air Interface ◽  
Surface Excess Concentration ◽  
Tail Water ◽  
Triton X

Measurements were made of the surface tension of the aqueous solutions of p-(1,1,3,3-tetramethylbutyl) phenoxypoly(ethylene glycols) having 10 oxyethylene groups in the molecule (Triton X-100, TX100) and cetyltrimethylammonium bromide (CTAB) with Zonyl FSN-100 (FC6EO14, FC1) as well as with Zonyl FSO-100 (FC5EO10, FC2) ternary mixtures. The obtained results were compared to those provided by the Fainerman and Miller equation and to the values of the solution surface tension calculated, based on the contribution of a particular surfactant in the mixture to the reduction of water surface tension. The changes of the aqueous solution ternary surfactants mixture surface tension at the constant concentration of TX100 and CTAB mixture at which the water surface tension was reduced to 60 and 50 mN/m as a function of fluorocarbon surfactant concentration, were considered with regard to the composition of the mixed monolayer at the water-air interface. Next, this composition was applied for the calculation of the concentration of the particular surfactants in the monolayer using the Frumkin equation. On the other hand, the Gibbs surface excess concentration was determined only for the fluorocarbon surfactants. The tendency of the particular surfactants to adsorb at the water-air interface was discussed, based on the Gibbs standard free energy of adsorption which was determined using different methods. This energy was also deduced, based on the surfactant tail surface tension and tail-water interface tension.

Standard Free Energy of Adsorption at Liquid Interfaces

1991 ◽  
pp. 277-292 ◽  
Author(s):  
D. K. Chattoraj ◽  
L. N. Ghosh ◽  
P. K. Mahapatra
Keyword(s):  
Free Energy ◽  
Standard Free Energy ◽  
Liquid Interfaces ◽  
Free Energy Of Adsorption

scholarly journals Comparison between surface and volumetric properties of short-chain alcohols and some classical surfactants

2016 ◽  
Vol 71 (1) ◽  
pp. 1 ◽  
Author(s):  
Magdalena Bielawska ◽  
Anna Zdziennicka ◽  
Bronisław Jańczuk
Keyword(s):  
Free Energy ◽  
Aqueous Solutions ◽  
Chemical Potential ◽  
Standard Free Energy ◽  
Dynamic Surface Tension ◽  
Short Chain ◽  
Critical Aggregation Concentration ◽  
Free Energy Of Adsorption ◽  
Dynamic Surface ◽  
Air Interface

<p>Measurements of the dynamic surface tension of the aqueous solutions of methanol, ethanol, propanol, CTAB and SDDS at their given concentrations were made. From the obtained results and the literature data it was concluded that the adsorption of short-chain alcohols at the water-air interface is somewhat similar to that of classical surfactants. For that reason the relationship between the Gibbs standard free energy of adsorption of short-chain alcohols and classical surfactants at that interface was established. The correlation between the chemical potential of mixing of alcohols and surfactants was also analysed. This analysis concerned the critical aggregation concentration (CAC) of alcohols and the critical micelle concentration (CMC) of surfactants. The chemical potential of surfactant mixing was calculated from the literature CMC data for the homologous series of alkyl sulfates, alkyl sulfonates, alkyl ammonium chlorides, alkyl trimethylammonium bromides, and alkyl pyridinium bromides. The influence of the hydrophobic chain length of alcohol and surfactant molecules on the Gibbs standard free energy of their adsorption at the water-air interface and their chemical potential of mixing were considered. It appeared that there is a linear dependence between these thermodynamic functions and the number of carbon atoms increased by 1 in the hydrocarbon chains of these compounds. This confirms clearly our conclusion that the behaviour of short-chain alcohols and classical surfactants at the water-air interface and in the bulk phase of aqueous solutions is similar. </p>

scholarly journals Synthesis and monolayer film of a series of new twin-tailed gemini cationic surfactants at the air/water interface

2008 ◽  
Vol 6 (3) ◽  
pp. 477-481 ◽  
Author(s):  
Zhi Chen ◽  
Yujun Feng ◽  
Dongliang Zhou ◽  
Puxin Zhu ◽  
Dacheng Wu
Keyword(s):  
Surface Pressure ◽  
Gemini Surfactants ◽  
Limited Area ◽  
Initial Surface ◽  
Water Interface ◽  
Spacer Length ◽  
Collapse Pressure ◽  
Initial Area ◽  
Air Water Interface ◽  
Pressure Area

AbstractA series of new dimeric surfactants, twin-tailed gemini surfactants, 2(12)-s-2(12), were successfully prepared and characterized, and their monolayer films investigated by the measurement of surface pressure-area (π-A) and surface pressure-time (π-t) isotherms at the air/water interface by a Langmuir film balance. Compared to their monomeric counterparts, their collapse pressure (γcollapse) is smaller, whilst all the molecular area parameters are larger. The limited area (Alimited) and the initial area (Ainitial) of these twin-tailed gemini surfactants change with increasing spacer length s, and the surface pressure decreases with increasing time. It was also found that the higher the initial surface pressure, the larger the attenuation.

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