Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group

Abstract

A series of new gemini surfactants without a spacer group, disodium 2,3-dialkyl-1,2,3,4-butanetetracarboxylates, were synthesized in a green chemistry context minimizing the use of organic solvents and applying microwaves (MW) when activation energy was required. Once the desired architecture was confirmed by means of the nuclear magnetic resonance technique (1H-NMR, 1H-1H COSY) for all the studied surfactants, the critical micellization concentration was determined by conductance measurements. The diffusion coefficient of micelles formed by the four compounds was characterized using pulsed field gradient (PFG)-NMR. Diffusion coefficients were found to be dependent on the concentration and on the number of carbon atoms in the alkyl chain. The absence of the spacer group, peculiar to this new series of gemini surfactants, may confer relatively low flexibility to the molecules, with potential implications on the interfacial properties, namely on micellization. These gemini surfactants might have interesting applications in the preparation of composite materials, in nanotechnology, in gene transfection and mainly, due to the low CMCs, as new interesting ingredients of cosmetics and toiletries.

Review on chemically bonded geminis with cationic heads: second-generation interfactants

“…However, CMC is like finger print evidence, always trusted as the pivotal character of a particular micelle in every surface research that includes micellization. CMC is defined as the concentration above which surfactant molecules abruptly form aggregation of micelles [18]. There is a list of 14 cationic surfactants in Table 1 where it is evident that the CMC sharply decreases for a gemini when compared with a traditional surfactant.…”

Progress in the Synthesis of Zwitterionic Gemini Surfactants

“…The properties of zwitterionic gemini surfactants are thought to be superior to those of conventional surfactants for their special structure. Compared with conventional surfactants, they have a strong adsorption capacity in the surface/interface, unusual aggregation morphologies, unique liquid rheology and good compatibility [38][39][40][41]. These unique properties will provide a further possibility of designing surfactants for various applications.…”

Amphiphilic Small Molecule Assemblies to Enhance the Solubility and Stability of Hydrophobic Drugs

“…16,17 It is well reported that assemblies formed from dimeric amphiphiles are generated more readily with a lower critical micelle concentration (CMC), and higher stability in aqueous medium than its monomeric counterparts. [18][19][20] Assemblies formed from amphiphiles with an aromatic core have also been reported. These amphiphiles assemble readily through π-π stacking interactions with a relatively low CMC.…”