Asp-Gly based peptides confined at the surface of cationic gemini surfactant aggregates.

Cationic gemini surfactants complexed with anionic oligoglycine-aspartate (called gemini peptides hereafter) were synthesized, and their aggregation behaviors were studied. The effects of the hydrophobic chain length (C10-C22) and the length of the oligoglycine (0-4) were investigated, and it was clearly shown by critical micellar concentration, Krafft temperature, and isothermal surface pressure measurements that the hydrophobic effect and interpeptidic interaction influence the aggregation behavior in a cooperative manner. Below their Krafft temperatures, some of them formed both hydro- and organogels with three-dimensional networks and the Fourier transform infrared measurements show the presence of interpeptidic hydrogen bonds.