**1.1 Synthetic cholesteric liquid crystal polymers**

Two multifunctional cholesteric liquid crystal polyesters (ChLCP), named PTOBDME [C34H36O8]n and PTOBEE [C26H20O8]n, with chemical formulations in **Figure 4**, were synthesized in our laboratory—through a condensation reaction between 4-4′-(terephthaloyl-dioxybenzoylchloride) (TOBC) and racemic glycol, DL-1,2-dodecanediol or DL-1,2-butanediol, respectively.

Although only racemic materials were used in their synthesis, a cholesteric, chiral morphology, theoretically unexpected, was found for PTOBDME, m = 9 in **Figure 4**. Evidence of this was obtained when a white solid, recrystallized as the second fraction from toluene mother liquor after the filtration of the polymer, was identified as –PTOBDME, with [α] 25 589 = −1.43 (1.538 g/100 ml, toluene). A similar result had been previously attained for liquid crystal PTOBEE, m = 1 in **Figure 4**. Its second fraction was isolated as –PTOBEE, with a value of [α] 25 589 = −2.33 (0.0056 mol/l, toluene). The synthetic method [11, 12], based on the previously reported by Bilibin [13, 14], leads to the obtaining of two or more fractions with progressively enriched diastereomeric excess. Its structure and diastereomeric excess could be characterized by NMR [15].

The structure of these optically active cholesteric LC polymers was characterized by NMR, Raman spectroscopy, steady-state fluorescence and SAXS/WAXS [16, 17], as rigid or semirigid helical LC polymers chains with flexible branches (chiral groups are located in the backbone), **Figure 5**, one of the major types of macromolecules forming the cholesteric mesophase [18].

Both polymers behave as thermotropic and lyotropic. They self-assemble in nanocavities in solution, with different conformations depending on the solvent

**Figure 2.**

*Types of liquid crystal mesophases: (a) nematic, (b) smectic a and (c) cholesteric, helical pitch.*

**Figure 3.** *Cholesteric mesophase of liquid crystal DNA exhibiting columnar hexagonal phase.*

#### **Figure 4.**

*The monomeric unit of cholesteric liquid crystal polyesters PTOBEE (m = 1) and PTOBDME (m = 9). The three different zones of the monomer are indicated:* mesogen*,* spacer *and* flexible side chain*. The chiral Centre is indicated by an asterisk. Torsion ϕ is shown. The aromatic-end acid and aliphatic-end alcoholic groups are also shown.*

#### **Figure 5.**

*Schematic representation of the cholesteric LC polymer type, with a rigid or semirigid helical chain with flexible branches (chiral groups are located in the backbone).*

and on the concentration [16]. They also get adsorbed on metal surfaces with reordering of the polymer in the interface [19], with a potential application on the biomedical and engineering field.

Besides they have proved to be biocompatible against macrophages and fibroblasts cellular lines. They are also able to interact with biomacromolecules: lipids (neutral and cationic), polynucleotides and nucleic acids.
