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The aggregation behavior of eight diastereomeric N-octylaldonamides, three enantiomers (galacton, mannon, glucon), and corresponding racemates was investigated mainly by electron microscopy. Head groups with a sterically undisturbed all-anti conformation (galacton, mannon) lead to "whisker"-type aggregates, which appear as rolled up, bilayer sheets in both aqueous and 1,2-xylene gels. One pair of 1,3-syn-positioned OH groups in the all-anti conformation neighboring on the amide group, lead to extremely thin helical whiskers of high curvature in water (glucon) or l,2-xylene (talon). If the outer OH groups are in syn positions in the all-anti chain conformations, the N-octylamides become highly water-soluble (allon, altron, idon) and form rolled up, bilayer sheets in 1,2-xylene (gulon). The length-to-diameter ratios in the aggregates are often higher than lo4. The fibers are stabilized by amide hydrogen bonds and/or the hydrophobic effect. They can be conceived as models for prebiotic assemblies, which may lead to condensation biopolymers in aqueous media.

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The fully reversible synthesis of noncovalent assemblies which are held together by directed bonds is called synkinesis. Micdlar fibres with a distinct stereochemistry and gels are formed by amphlphfles forming strong hydrogen bonds between chiral head groups. The 3D-crystallization of such molecular assemblies, without dominating repulsive hydration forces, is prevented by the curvature of the fibres. Curvature might perhaps be directly connected with chirality. Addition of enantiomers often leads to an irreversible destruction of gels. Recent developments relating to 'hydropbobic water' in /~ngstriim-wide membrane gaps are also shortly discussed.