Viscoelastic Fluorescent π-Conjugated Polymer Liquids toward Direct Visualization of Microphase Separation

Abstract

In this study, three π-conjugated copolymers (PPTBT, PPT, and PPP) functionalized with the same length of the Guerbet-type side chains but different insertions of πconjugated units were designed and synthesized. These copolymers exhibited intense blue, green, and red emissions in a solvent-free state with good fluidity at room temperature. The effects of different π-units on the photophysical and rheological behaviors, miscibility, and microphase separation of these polymer liquids were thoroughly explored. Compared with conventional conjugated polymers, photophysical, thermal, and morphological results and rheological analysis showed that three copolymer liquids exhibited intensive emissions and high viscoelasticity in the condensed state, enabling the direct visualization of microphase separation behaviors by polymer blending techniques. These findings suggested that the use of highly viscoelastic conjugated polymer liquids with excellent fluorescence can play a critical role in the future design of efficient luminescent polymer liquids for the next-generation optoelectronically and external stimuli-responsive smart soft materials.

Conjugated polymers with near-infrared (NIR) optical absorption: structural design considerations and applications in organic electronics

“…82 Relative to their linear counterparts, branched alkyl sidechains provide improved polymer solubility in organic processing solvents, regulate polymer aggregation, and increase polymer chain entanglement. 83–85…”