Synthesis and characterization of asymmetrical gemini surfactants

Abstract

The effect of variation in the length of surfactant hydrocarbon tail groups was tested in a series of dissymmetric gemini surfactants (N-alkyl N,N,N,N-tetramethyl-N-(6-pyren-6yl)-hexyl)propane-1,3-diammonium dibromide designated as CCCBr, with m = hexyl pyrene, and n = 8, 12, 14, 16, and 18. The aggregation properties of these surfactants have been investigated by means of H NMR, fluorescence spectroscopy, surface tension and electrical conductivity measurements. The critical micelle concentration (CMC) was determined using surface tension and confirmed using the specific conductance method. Krafft temperatures and the degree of micelle ionization (α) were obtained from specific conductance measurements. With an increase of the dissymmetry (m/n) ratio, the CMC decreased linearly and an increase in the Krafft temperatures was observed for all of the gemini surfactants. α values for the dissymmetric GS were higher than those of the m-3-m counterparts, which may be attributed to enhanced micelle-micelle interactions that arise from increased hydrophobicity of the hydrocarbon chains. The introduction of the bulky pyrenyl tail group resulted in much lower CMC values compared to their symmetrical counterparts affecting the packing of these surfactants at the air/water interface, which resulted in high-ordered structures (lamellar and inverted micelles). This in turn affected the thermodynamic parameters of the micellization.

Multifunctional Gemini Surfactants: Structure, Synthesis, Properties and Applications

“…Surface activity of heterogeminis strongly depends on degree of the asymmetry. For pyrenebased dissymmetric gemini surfactants synthesized in five-step reactions ( Figure 16) [76], the Krafft temperatures increase with the increase of the alkyl chain length. Similarly, CMC values are much lower than those of their symmetrical counterparts.…”

“…The antimicrobial activity depends not only on the length of the substituent but also is dependent on the length of spacer [76,137,143,147,148]. In general, the longer the spacer, the better the antimicrobial activity ( Figure 26) [77].…”

Synthesis and Characterization of Surface‐Active Ionic Liquids Used in the Disruption of Escherichia Coli Cells

“…Besides the imidazolium family, other types of SAILs have also been investigated, namely ammonium‐, phosphonium‐, morpholinium‐, and guanidinium‐based SAILs . Brown et al .…”

“…The results showed that the absence of the spacer group may confer relatively low flexibility to the molecules, with potential implications on the interfacial properties, namely, on micellization . In 2017, Muslim and co‐workers reported the synthesis and characterization of two groups of asymmetrical dicationic ILs based on ammonium cation. The first group consisted of SAILs with one hexyl pyrene tail and one alkyl chain, whereas the second group had two asymmetrical alkyl chains.…”

Facile construction of gemini-like surfactants at the interface and their effects on the interfacial tension of a water/model oil system

“…For example, the surface/interface activity of gemini surfactants is orders of magnitude higher than that of single-chain surfactants. [6][7][8][9][10][11][12][13][14] The oil/water interfacial tension (IFT) reduction is the main mechanism of surfactant ooding. Thus, gemini surfactants have great potential for EOR application.…”