Counteranion effect on micellization of cationic gemini surfactants 14-2-14: Hofmeister and other counterions.

The effect of counterions was investigated and analyzed to probe the principal ionic effects influencing the micellization behavior of dimeric cationic surfactant ethanediylbis(dimethyltetradecylammonium), referred to as gemini 14-2-14. The 30 counterions were classified to four different families depending on their nature: (1) small and inorganic counterions which are typically taken from the Hofmeister series were studied to focus on the effect of ion type; (2) n-alkyl carboxylate counterions were studied to focus on the effect of the hydrophobicity of counterions; (3) aromatic carboxylate counterions were included to focus on the effect of the position of substitutions; and (4) other counterions were included in order to shed light on other parameters. By investigating the critical micelle concentration (CMC), ionization degree of micelle (alpha), free energy of micellization (DeltaG(M)), and aggregation numbers N of the gemini surfactant with these different types of anions, we demonstrated the effect of different ion properties independently.

Control of nano-micrometric twist and helical ribbon formation with gemini-oligoalanine via interpeptidic beta-sheet structure formation.

Confinement of anionic oligo-alanine peptides at the surfaces of cationic membrane by ionic interaction can induce their secondary structure formation; such organized peptides reciprocally transfer their chirality to membranes with non-chiral amphiphiles and their supramolecular chiral structures can be tuned both by peptides and amphiphiles structures.