Effect of aromatic ring in the alkyl chain on surface properties of arylalkyl surfactant solutions

Abstract

Surface properties of two series of anionic arylalkyl surfactants, containing different aromatic rings in the straight aliphatic chain, sodium N-aryloleyl-N-methyl-2-aminoethanesulfonates and sodium N-aryloleyl p-methoxyanilinesulfonates, were investigated. An increase of the aromatic ring size in the alkyl chain increases the critical micelle concentration (CMC) and surface tension at CMC. However, this also decreases the efficiency and effectiveness in reducing water surface tension. The dominant factor of the decrease of efficiency and effectiveness is attributed to the function of the hydrophilic segment and hydrophobic segment for arylalkyl surfactants, respectively. The same results are found in the standard free energy of adsorption (∆G°a ds ) and the standard free energy of micellization (∆G°m ic ) values. Moreover, with the increase of the aromatic ring size, the adsorption and micellization of arylalkyl surfactants begin to weaken. The data indicate that some parts of surface properties for arylalkyl surfactants are affected by the bulkiness of the arylalkyl chain. The results provide opportunities for further detailed examination of surface properties of arylalkyl surfactants with other branched alkyl chains.Paper no. S1529 in JSD 9, 245-248 (Qtr. 3, 2006).The traditional methods of altering hydrophobicity of a surfactant are to vary the length of the straight alkyl chain or the different hydrophilic groups. It is well known that an increase of the straight alkyl chain length of conventional alkyl surfactants can decrease the critical micelle concentration (CMC) and increase the efficiency and effectiveness in reducing water surface tension (1,2). However, the branched aliphatic chain of the surfactants exhibits complicated effects on their CMC and surface tensions (3-6). The relationship between the structure of the hydrophobic chain and surface properties has already been studied by Matsuoka and Moroi (7) and Aksenenko and colleagues (8). The effects of alkylbenzenesulfonate molecules with different branched aliphatic chains on adsorption and surface tension were also reported (3). For these surfactants, the aromatic rings are usually attached by hydrophilic groups. Arylalkyl surfactants, differing from the existing surfactants, having the sulfonate group attached to the alkyl chain rather on the aromatic ring, exhibited better solubility in water and better thermal stability than the conventional alkyl or alkyl-aryl sulfonate surfactants (9,10). In this study, the effects of increasing the arylalkyl chain size from phenyl to naphthyl on their surface properties are reported. The values of CMC and surface tensions (γ cmc ) for these arylalkyl surfactants increase with an increase of arylalkyl chain size. Thus, the effect of structural features on their surface behavior is analyzed through changes in surface properties, including the surface excess concentration at surface saturation (Γ m ), the effectiveness of adsorption, the area per surfactant molecule at the air/water interface at surface saturat...

Fatty Acids in Heterocyclic Synthesis. Part XIV: Synthesis of Surface Active Agents from Some Novel Class of Oxadiazole, Thiadiazole and Triazole Derivatives Having Microbiological Activities

“…Within each series of surfactants, noting that the hydrophobic part is unchanged, the smallest CMC value is reached where n = 3, i.e., when the adhesive force is at its least (Graphs of surface tension vs log of concentration of added surfactant, used in the determination of the CMC are presented in the supplementary material section). Previous reports agree with our results [55].…”

“…The values of the maximum surface excess C maxexpressed in mol/cm 2 were calculated from surface or interfacial data by the use of Gibbs equation [34], Eq. (3):…”

Novel Synthesis of a New Surfactant 4‐((4‐Bromophenyl)(dodecyl)amino)‐4‐Oxobutanoic Acid Containing a Benzene Ring Using a Copper Catalyst Cross‐Coupling Reaction and its Properties

“…CMC critical micelle concentration, c CMC surface tension at CMC, C CMC maximum surface excess concentration at CMC, A CMC occupied area per molecule at CMC, pC 20 the efficiency of surface adsorption, CMC/C 20 the relative effects of some structural or microenvironmental factor on adsorption a Ref. [7], test at 25°C;…”

“…Surfactants containing an aromatic group have various uses in industrial applications and fundamental chemical research [1], their unique structure has found applications in micellar catalysis [2][3][4], synthetic lipids and amphiphiles [5], and Enhanced Oil Recovery [6][7][8]. Thus, application of new synthetic methods to synthesize these kinds of aromatic surfactants is important for research into their properties.…”

Fatty Acids in Heterocyclic Synthesis. Part XVII: Synthesis of Non Ionic Surfactants Containing Piperidine, Piperazine, Imidazole Based on Thiadiazole and Microbiological Activities Evaluation

“…where δγ surface pressure in mN/m, C surfactant concentration and (δγ/δlogC) T is the slope of surface tension versus concentration curves below CMC at constant temperature [36].…”