Structural Heterogeneity in Semiconducting Polymers

July 1, 2021
Structural Heterogeneity in Semiconducting Polymers
Schematic illustration of a CG-MD simulated conjugate polymer in solution state, with the backbone shown in blue. Double sided arrows show the persistence length determined from measurements of the whole chain compared to that determined by directly measuring the backbone using CV-SANS.

Scientific Achievement

Direct measurements of the backbone in semiconducting poly(3-decylthiophene) show that the persistence length of its conformation is 1.05±0.1 nm, which is half of that estimated from previous measurements of the full polymer.

Significance and Impact

The potentially technologically significant optoelectronic properties of these functional polymers are critically dependent on the backbone rigidity determined in this work.

Research Details

  • Contrast variation small-angle neutron scattering (CV-SANS) experiments on poly(3-alkylthiophenes) with deuterated and protiated side chains in a mixture of deuterated and protiated chlorobenzene (dCB:CB) solvent enabled decoupling of the backbone and side-chain scattering signal.
  • The scattering studies were accompanied by and agree with coarse-grained molecular dynamics (CG-MD) simulations.

“Decoupling Poly(3-alkylthiophenes)’ Backbone and Side-Chain Conformation by Selective Deuteration and Neutron Scattering”,
Zhiqiang Cao, Zhaofan Li, Song Zhang, Luke Galuska, Tianyu Li, Changwoo Do, Wwnjie Xia, Kunlun Hong, and Xiaodan Gu,
Macromolecules 53, 11142-11152 (2020).