Aggregation Properties of Amide Bearing Cleavable Gemini Surfactants by Small Angle Neutron Scattering and Conductivity Studies

Abstract

The micellar aggregation of different amide bearing cleavable gemini surfactants with varying methylene spacer chain length (m = 2, 4, 6, 8, and 12) along with the corresponding monomeric surfactant in aqueous media has been investigated by conductometric and small angle neutron scattering (SANS) studies. The critical micellar concentration (CMC) values of gemini surfactants were found to be very low (CMC = 0.08-0.19 mM) and were 23-55 times lesser than the corresponding monomeric analogue (CMC = 4.4 mM). With increase in the spacer chain length, CMC was found to decrease whereas the degree of ionization was found to increase. SANS data have been analyzed by considering the screened coulombic interactions between the micelles to compute the interparticle structure factor S(Q). The extent of micellar growth and the variation of shapes of the micelles formed by these new surfactants in aqueous solution have been found to depend strongly on the spacer chain length. It was observed that the extent of micellar growth and variation of micellar shapes are more pronounced for surfactants with short spacer chain length (m ≤ 4), whereas the surfactants with a long spacer chain length (m ≥ 6) showed slight variation of these properties in aqueous solution. The effects of the variation of the concentration and temperature on the SANS spectra (and hence on the microstructure) of the gemini surfactant (m = 4) were also examined. With an increase in concentration the aggregation number (N) and size of the micelles (the ratio of semimajor axis (a) to semiminor axis (b = c)) increased whereas opposite phenomena was observed with an increase in temperature.

Effect of cationic head group on micellization behavior of new amide-functionalized surface active ionic liquids

“…38,39 Following that, 2-chloro-N-dodecylacetamide was subsequently quaternized by different heterocyclic amines (N-methyl piperidine, N-methyl pyrrolidine, N-methyl imidazole and N-methyl morpholine) in the second step to get amide-functionalized SAILs. The detailed methodology of synthesis and characterization data (NMR and mass) are provided in Annexure 1 (ESI †).…”

Synthesis of Gemini Surfactants and Evaluation of Their Interfacial and Cytotoxic Properties: Exploring the Multifunctionality of Serine as Headgroup

“…[39][40][41][42] The higher toxicities displayed by the amide and ester surfactants could then be the result of the breaking of the gemini molecule (at the spacer linkage) into two molecules of monomeric serine-derived surfactant, which would double the effective surfactant concentration of cationic surfactant in contact with the cells. It has been reported that surfactants with cleavable bonds (i.e., amide and ester) can easily undergo enzymatic degradation.…”

New ester based gemini surfactants: the effect of different cationic headgroups on micellization properties and viscosity of aqueous micellar solution

“…10 wt%, 20 wt%, 30 wt% and 40 wt%) at 25 1C and the results of the experiments are shown in Fig. [49][50][51][52] The presence of this polar ether linkage in the morpholinium headgroup in addition to the ester group may result in the formation of hydrogen bonding between the nonbonding electrons on oxygen atoms and water molecules, which ultimately influences not only the thermodynamic behavior but also the rheological behavior of the surfactants. 48 The morpholinium gemini surfactant: [C12MOR(2Es)-C12MOR]2Br demonstrated lower viscosity compared to the other gemini surfactant solutions.…”