Effects of Side-Chain Topology on Aggregation of Conjugated Polymers

Abstract

Controlling interchain interactions in conjugated polymers is critical to the development of high performance materials. These interchain interactions are dictated by the aggregation and self-assembly of conjugated polymers in solution and from processing steps, such as thermal annealing, in the solid state. Herein, a macrocyclic benzodithiophene building block for conjugated polymers is developed, and the properties of the resulting polymers are compared to analogous acyclic derivatives. The properties of small molecule macrocyclic BDT compounds show the influence of the side-chain substitution on the thermodynamic forces of self-assembly. Comparison of the optical properties of conjugated polymers with macrocyclic and acyclic side-chains in solution and the solid state reveals the ability of the macrocyclic side-chain to modify the structure of aggregates. Grazing incidence wide-angle X-ray scattering shows that the macrocyclic polymers can remain ordered in the solid state while having higher photoluminescence yields than the acyclic derivatives.