Effect of Structural Parameters on the Supramolecular Organization of Rigid‐Flexible Polymers

Abstract

Summary: Rigid‐flexible polyethers consisting of terphenyl and aliphatic segments of various lengths along their main chains and disubstituted by dendritic wedges of various generations (G0, G1, and G2) are examined in their bulk states. Characterization of phase transitions has been performed by means of differential scanning calorimetry (DSC) and was supported by structural information obtained from small‐angle light scattering (SALS) and polarized optical microscopy (POM) experiments. In order to characterize order on the molecular size scale, two‐dimensional (2D) wide‐angle X‐ray diffraction (WAXS) experiments have been performed for macroscopically oriented samples. All results pointed out a highly ordered nature of these materials. Both monomers and polymers were characterized. In the case of polymers, structures consisting of layered backbone sheets separated by the side dendritic moieties filling the space between them were deduced. In all cases, strong effects of molecular parameters, such as main chain flexible spacer's length and sizes of substituents, on transition temperatures (odd‐even effect), degree of orientation, and distances characteristic for the supramolecular structures, were observed.Example of 2D X‐ray diffraction patterns recorded for oriented films of the polymers PETH‐(2OC12H25) (the zero generation).magnified imageExample of 2D X‐ray diffraction patterns recorded for oriented films of the polymers PETH‐(2OC12H25) (the zero generation).

Role of main chain rigidity and side-chain substitution on the supramolecular organization of rigid–flexible polymers

“…Besides the main melting transition at about 446 K, a weak endothermic peak is observed at w323 K during the second heating run. Comparing this behaviour with that of the respective diol with the three phenylene rings [34], an increase in the main transition temperature is observed that is expected by the increase in the conjugation length. Nevertheless, the first transition at 323 K, is in the same range supporting the notion that is mostly related to the dodecyloxy side-chains.…”

Correlation between Chain Packing and Photoluminescence for PPV/PPE in Macroscopically Oriented State: Side Chain Effects

“…Structural Analysis. (PPV/PPE)s 1 and 2 were processed at different temperatures using a microextrusion process to prepare macroscopically oriented filaments, and temperature-dependent structural parameters were extracted from their wide-angle X-ray patterns recorded using a 2D detector. 24i,, In all cases, diffractions were seen in the low-angle equatorial region. These periodicities are presumed to result from nanoscale segregation between π-conjugated polymer backbones and aliphatic side chains that are immiscible with each other.…”

Dendron-Mediated Self-Assembly, Disassembly, and Self-Organization of Complex Systems

“…586 Here aliphatic-aromatic segregation induced a greater-degree of order as evidenced by DSC, Small-Angle Light Scattering (SALS), TOPM, and XRD. 587 Oriented fiber XRD exhibited 2D layering of dendronjacketed terphenyl units and supported a N structure (Figure 148a) that is converted to an S phase (Figure 148b) upon annealing.…”