Scratch‐Healing of Conjugated Polymers: Flexibly Linked PTB7‐Th Copolymers and Their Blends

ABSTRACT PTB7‐Th‐based conjugated polymers featuring flexible linkers have been prepared by Stille cross‐coupling. Alkyl linkers with different lengths (C6, C12, C20) as well as an oligo(ethylene glycol) linker have been introduced into statistical copolymers with different linker contents (ranging from 10% to 90%). The molar masses of the polymers have been studied by size‐exclusion chromatography, and the polymer composition by 1 H NMR spectroscopy. Furthermore, the thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The optical properties of the polymers have been analyzed in solution as well as in film. Scratch healing tests revealed a better healing ability for higher linker contents. In order to mitigate the deterioration of the optical properties caused by the higher linker content, blends of donor polymers with a high linker content and a low linker content have been prepared. This new strategy resulted in good optical properties as well as sufficient mobility for the self‐healing process.