**4. Conclusions**

The synthetic multifunctional cholesteric liquid crystal polyesteramides designed as PNOBDME (C34H38N2O6)n and PNOBEE (C26H22N2O6)n are reported as chemical modifications of multifunctional cholesteric LC polyesters, involving new properties but holding the precursor helical macromolecular structure.

Molecular mechanics models of the new polymers show helical polymeric rigid chains. Homopolymerization was simulated with head-to-tail orientation and torsion angle between monomers fixed to 180°. Isotacticity was finally imposed on the polymer chains, explained in terms of the higher reactivity of the primary hydroxyl regarding the secondary one in the glycol through the polycondensation reaction.

Two independent sets of signals experimentally observed by <sup>1</sup> H-NMR for each enantiomer of PNOBDME and PNOBEE (while the R/S ratio of asymmetric carbon atoms remained 50:50) are related with two possible staggered diastereomeric conformers, *gg* and *gt* of torsion *φ*, containing the asymmetric carbon atom in the spacer, along the polymer backbone. One of these two systems is designated with an apostrophe ('), and the other is designed without an apostrophe (). The combination of a helix with two screw senses and the two absolute configurations by the presence of the asymmetric carbon atom provides four diastereomeric structures.

Molecular models of the four diastereomers *Rgg*, *Sgg*, *Rgt* and *Sgt* are provided as well as their polymer chains with 10 and 60 monomeric units.

The thermal behaviour of the new synthesized cholesteric liquid crystal polyesteramides has been studied by TG and DSC. An endothermic peak assigned to the first-order transition from crystal to liquid crystal mesophase is observed in both polymers.

ORD values are provided for polyesteramide PNOBDME. The first fraction of the polymer did not show a net optical activity but values fluctuating from positive to negative, but the second fraction presented low positive values +1.02°, at 598 nm; +1.65°, at 579 nm; and +2.9°, at 435 nm but very high optical activity +600° to +950°, at 579 nm, when increasing temperature from 25–35°C.

Morphology of powdered PNOBDME by ESEM shows spherical clusters of about 5 μm in diameter, homogeneously dispersed.

Simultaneous SAXS/WAXS patterns of PNOBDME are registered during heating from 30 to 200°C, with a synchrotron radiation source.
