Self-Assembly of Octaaminoamido Derivatives of Resorcin[4]arene in Water − A “Cell-Like” Submicron-Scale Hydrogel Structure

We have prepared four new octaaminoamide resorcin[4]arenes having hydrocarbon chains of different lengths (1, 2: R = CH3; 3, 4: R = C11H23) and different terminal groups (1, 3: NH2; 2, 4: NMe2). The surface tension and self-assembly of aqueous solutions of 2−4 were studied and their critical micelle concentrations (CMC) were determined. At the water/air interface, compound 2 forms a multilayer structure, whereas compound 3 forms a bilayer and compound 4 a monolayer structure. In addition, we found that compound 3 has a second CMC (CMC2). A dynamic light scattering study indicated that, at a concentration of 0.1 wt% (i.e., > CMC2), 3 forms nanodimensional aggregates; increasing the concentration up to 1.2 wt% results in the formation of strong transparent gels. For hydrogels having 5 wt% of 3, SEM images demonstrated the formation of submicron-scale “cell-like” aggregates. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)