Unveiling the hydrogen bonding network in liquid crystalline natural-based glycosides containing polymeric complexes: experimental and theoretical assessment

In this work we present a facile and versatile strategy to prepare new amphiphilic compounds obtained from natural sources, avoiding costly covalent synthetic stages, and we introduce a powerful methodology to describe hydrogen-bonding networks in carbohydrates liquid crystal. A series of new glycosides has been prepared by mixing a natural-based mannoside, αManPKO, with three different polymeric substrates: poly(ethylene oxide), PEG, poly(4-vinyl pyridine), P4VP, and a block-copolymer containing PEG and P4VP segments, PEG45-b-P4VP18. The materials have been characterised by differential scanning calorimetry, polarised optical microscopy and small-angle X-ray diffraction. The resulting complexes are assembled by hydrogen-bonding and form smectic A phases, with the polymeric chains spread along the surface of the glycosides bilayers. By using Fourier-transform infrared spectroscopy, FT-IR, and molecular simulations, we have assessed the selectivity of the hydrogen bonds formed between αManPKO and the polymeric segments. Our results suggest that the assembly of the polymeric complexes must be explained by a combination of interfacial mixing between the polymer/glycoside units at the bilayer boundaries (favoured by PEG) and the formation of strong hydrogen bonds (favoured by P4VP).