*3.3. Rheology*

Dynamic rheological data of molten PPM and the related copolymers were obtained from frequency sweeps over the range of 0.3–22 rad s<sup>−</sup><sup>1</sup> at 5% strain at the temperature of 120 ◦C (the temperature of coating application). The applied 5% strain was confirmed to be within the linear viscoelastic region by strain sweep measurements. The complex viscosity (η\*) of PPM and the copolymers are shown in Figure 4. The copolymer containing 6.1% mol/mol of *n*-octyloxy repeat units revealed a slight decrease of viscosity compared to PPM itself, while increasing the fraction of units with *n*-octyloxy side-chains to 13.4% mol/mol led a pronounced drop of viscosity (decrease by order of magnitude). It has to be noted that the measurements were performed at the film processing temperature (see below) which is well above the glass transition temperature of the polymers (Table 1). It appears, therefore, in agreemen<sup>t</sup> with glass transition temperatures, that *n*-octyloxy side-chains act as spacers between the polymer backbones decreasing the cumulative intermolecular forces along the polymer chains, thus inducing a decrease in viscosity.

**Figure 4.** Effect of *n*-octyloxy side chains on the complex viscosity. From top to bottom: PPM (pink line), 6.1% mol/mol octyloxy units (blue line) and 13.4% mol/mol octyloxy units (black line).
