Influence of Spacer Nature on the Aggregation Properties of Anionic Gemini Surfactants in Aqueous Solutions

Abstract

A series of anionic gemini surfactants with the same structure except the spacer nature have been studied. Their solution properties were characterized by the equilibrium surface tension and intrinsic fluorescence quenching method. The critical micelle concentrations (CMC), surface tension at cmc, C 20 , and the micelle aggregation number (N) were obtained. The surface tension measurements indicate that these gemini surfactants have much lower cmc values and great efficiency in lowering the surface tension of water compared with those of conventional monomeric surfactants. Furthermore, the standard free energy of micellization for anionic gemini surfactants was also determined. The results showed that the nature of the spacer has an important effect on the aggregation properties of gemini surfactants in aqueous solutions. The surfactant with a hydrophilic, flexible spacer was more readily able to form micelle compared with the surfactant with a hydrophobic, rigid spacer, which leads to a lower CMC value, larger N, more negative free energy of micellization, and a more closely packed micelle structure.

Use of surfactants for the remediation of contaminated soils: A review

“…Zhu [113] studied a homologous series of anionic geminis with different spacer nature, and found that a hydrophilic, flexible spacer was more conducive to the formation of micelle than a hydrophobic, rigid spacer, thus giving more stable micelles and a better surfactivity. In Scheme 2, several gemini (dimeric) surfactants with different structures and a gemini-type surfactant with three hydrophobic and hydrophilic groups are given [114][115][116][117][118][119][120].…”

Aggregation behavior of anionic sulfonate gemini surfactants with dodecylphenyl tails

“…Zhu et al [31] studied the effect of spacer type on the aggregation of sulfonate gemini surfactants; the authors examined an ethylene unit as a flexible hydrophobic spacer; an oxyethylene unit as a flexible hydrophilic spacer; and a vinylene unit with a carbon-carbon double bond as a rigid hydrophobic spacer. The authors showed that the gemini surfactants containing a hydrophilic flexible spacer with an affinity for forming hydrogen bonds and high conformational freedom exhibited a greater capacity for micellization compared with the gemini surfactants with a hydrophobic rigid spacer.…”

“…Anionic sulfonate gemini surfactants with dodecylphenyl tails and oligomethylene spacers were synthesized by modifying the method presented by Zhu [31] …”

Anticancer cytotoxicity assessment of cationic surfactants metal complexes

“…According to Table 2, another important parameter of surfactants, Pc 20 , could also be interpreted. Pc 20 represented the concentration required to reduce the surface tension of water by 20 mN/m, and reflected the capability of surfactants adsorbing on the air/solution interface [22], and the less the Pc 20 value was, the greater the adsorbing efficiency was. It is clear that the metal complexes of VSBO cationic surfactants have higher Pc 20 than their parent cationic.…”