Synthesis and Characterization of Rigid Rod Poly(p-phenylenes)

Abstract

The polymer PP, which consists of a poly(p-phenylene) backbone with sulfonate ester and dodecyl side groups, is synthesized by a Pd-catalyzed coupling of the 1,3-propanediol diester of 2-dodecyl-5-methyl-1,4-benzenediboronic acid with 2,2′-bis(3,5-di-tert-butylbenzenesulfonato)-4,4′-dibromobiphenyl. Polymers with various molar masses are obtained, which are soluble without aggregation in conventional organic solvents. The good solubility of this rodlike polymer allows the accurate determination of the molar mass by light scattering, osmometry, and SEC with universal calibration. The dependence of the intrinsic viscosity [η] on the molar mass is determined from both the Mark-Houwink-Sakurada equation and the wormlike chain model. The low value of the persistence length (13 nm) indicates that these polymers are relatively flexible. It is shown that an approximate value of the persistence length, together with the parameters of the Mark-Houwink-Sakurada equation and the wormlike chain model, can be determined using only a single polydisperse sample.

Exploring the origin of high optical absorption in conjugated polymers

“…The positive correlation between persistence length and extinction coefficient has been used previously to infer conformation from extinction 33 , but not in the context of designing strongly absorbing conjugated polymers. We note here that calculated values of p are generally larger than values determined experimentally 33,34 suggesting that other factors than the theoretical potential energy surface may influence chain extension in practice.…”

Diffraction analysis of highly ordered smectic supramolecules of conjugated rodlike polymers

“…Based on the whole data set the estimated L of PPY is 50-80 Å. As the persistence length of substituted poly(p-phenylene), an analogous polymer to PPY, is 75-200 Å (Vanhee et al, 1996), this distance is regarded as the length of rodlike sections in PPY as well. L of PPY differs from the L ∼ 300 Å calculated from the reported M w ∼ 6000 g/mol (M w /M n ∼ 1.2-1.6) (Tammer et al, 2002).…”

Structure and Phase Equilibria of Polyelectrolytic Hairy-Rod Supramolecules in the Melt State

“…Moreover, the theory deals with completely rodlike polymers, whereas the persistence length of this class of polymers is obviously finite, for example, 75-200 Å for alkyl substituted poly(p-phenylenes). 33 Experimentally, we find microphase-separated uniform phases when y < 2.0, and therefore the amount of side chains was chosen around this value (y ) 0.2, 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, and 3.0). The rod concentration, f = (1 + 0.9y)/(1 + 1.6y), in this work was relatively high.…”