Sugar-Based Polyamides: Self-Organization in StrongPolar Organic Solvents.

Periodic patterns resembling spiralswere observed to form spontaneouslyupon unassisted cooling of d-glucaric acid- and d-galactaric acid–based polyamide solutions in N-methyl-N-morpholine oxide (NMMO) monohydrate. Similarobservations were made in d-galactaric acid-based polyamide/ionicliquid (IL) solutions. The morphologies were investigated by optical,polarized light and confocal microscopy assays to reveal pattern details.Differential scanning calorimetry was used to monitor solution thermalbehavior. Small- and wide-angle X-ray scattering data reflected thecomplex and heterogeneous nature of the self-organized patterns. Factorssuch as concentration and temperature were found to influence spiraldimensions and geometry. The distance between rings followed a first-orderexponential decay as a function of polymer concentration. Fourier-TransformInfrared Microspectroscopy analysis of spirals pointed to H-bondingbetween the solvent and the pendant hydroxyl groups of the glucoseunits from the polymer backbone. Tests on self-organization into spiralsof ketal-protected d-galactaric acid polyamides in NMMO monohydrateconfirmed the importance of the monosaccharide’s pendant freehydroxyl groups on the formation of these patterns. Rheology performedon d-galactaric-based polyamides at high concentration inNMMO monohydrate solution revealed the optimum conditions necessaryto process these materials as fibers by spinning. The self-organizationof these sugar-based polyamides mimics certain biological materials. [ABSTRACT FROM AUTHOR]