ISSN:
1435-1536
Keywords:
Saccharide-based amphiphiles
;
4-alkyl-semicarbazones
;
gelation of saccharide-amphiphiles
;
self-organization
;
supramolecular organization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The synthesis of 4-alkyl-semicarbazones derived from reducing sugars and semicarbazides is presented as a convenient route for the preparation of amphiphilic saccharides. This semicarbazone route allows to employ a large variety of reducing sugars as hydrophilic building block for saccharide tensides. The preparation of two series of amphiphiles based on D-maltose with non-methylated and mono-N-methylated semicarbazone units is described. Then-alkyl chains were varied fromn-octyl ton-hexadecyl. Various maltotriose derivatives have also been prepared. Critical micelle concentration (CMC) as well as critical gel concentration of the derivatives were studied in dependence of then-alkyl chain length. Both values decreased with increasing length of then-alkyl chain. Self-organization of the gels was studied by transmission electron microscopy of freeze-fractured samples. Due to the supramolecular organization of the amphiphiles, the gels consisted of twisted rope-like molecular assemblies with the same helical twist sense. The helical pitch depended on the hydrophilic/lipophilic balance. In contrast to gels onn-alkylgluconamides, the gels were formed in dilute aqueous solution and exhibited striking longevity without additional stabilization by surfactants. In the solid, the amphiphiles exhibited thermotropic transitions to partially disordered mesophases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00652259
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