Vesicular aggregation and morphologic evolvement of a flexible-rigid block hydrogen-bonding complex

In this paper, we selected a flexible poly(ethylene oxide) (PEO) connected to a stilbazole head group and a semi-rigid dendron of gallic acid with three alkyl chains to prepare an amphiphilic complex through hydrogen bonding. The structure of flexible-rigid complex has been characterized by H-1 NMR, IR and DLS. From the calculation of the binding interaction, the bonded complex occupies ca. 59.5% of total amount of molecules at the molar ratio of 1:1 of its two components, accompanied by the stability constant K-sc about 369 L/mol. The complex displays vesicular aggregation in toluene mixed with a certain amount of DMSO and the structural characterization indicates a symmetrical bilayer with PEO component locating outside towards the solution based on the analysis of contact angle. More interesting, tubular architecture of the complex is observed and found with the similar bilayer structure as that of the vesicular aggregation. The tubules are confirmed to derive from the vesicular aggregation through aging the vesicular structure. It is believed that the present investigation is helpful for the understanding of the dynamics of the vesicle evolvement based on the flexible-rigid complex. (C) 2008 Elsevier Ltd. All rights reserved.