Abstract
I will discuss here the regulation of molecular arrangement within the supramolecular film formed from an oligoleucine-containing amphiphile (Chart I). The oligoleucine-containing amphiphile possessing three and more consecutive leucinate residues initially formed a β-sheet structure, which stacked by a fastener-like action between the side chains of leucines (Leucine-fastener) within the different β-sheets (Fig. 3). The molecular arrangement was improved by hydraulic press of the xero-gel of MEE-Leu6 Glu(OC12)2 (Fig. 8) or by warming the air-dried cast film of N+C11-Leu4 Glu(OC12)2 (Figs. 3, 9 and 10). The tensile stress of the hydraulic pressed film increased to ca. 2.5MPa, when a larger pressure was applied to form the pressed film (Fig. 8). Depending on the increase of the tensile stress, the absorbance of FT-IR bands increased (Fig. 11). On the other hand, the same increase of the FT-IR spectral intensity was observed, when the air-dried cast film was warmed (70°C) and then cooled (r. t. ). These results suggest that the mechanical processing or the thermal treatment should promote the mechanical strength of the supramolecular film of the oligoleucine-containing amphiphile. This is because a large pressure or a higher temperature brought about tight coupling between the nearest neighboring β-sheets of the oligoleucine derivatives.
