Complex effect of ethyl branching on the supramolecular structure of a long chain neoglycolipid

A new ethyl-branched neoglycolipid was synthesised from d-maltose and N-tetradecanoyl-(2R)-2-aminobutanol in three steps. The physical properties of three glycolipids (non-branched spacer, without spacer with same alkyl chain and longer alkyl chain) of similar structure were also investigated for comparison. The liquid crystalline properties were studied using polarising microscopy and the contact preparation method. Investigation of the micelle formation and structure was performed using surface tension measurements and small angle neutron scattering. The interaction between the amidic and the ethyl group leads to a better solubility of the compound with a branched ethyl spacer compared to the non-branched one and favours the formation of long cylindrical micelles. The micelle length is significantly higher than reported for n-alkyl maltosides of similar chain length, i.e., the non-polar ethyl spacer gives a better packing of the polar groups.