Poly[2,7‐(9,9‐dihexylfluorene)]‐block‐Poly(2‐vinylpyridine) Rod–Coil Star‐block Copolymers: Synthesis, Micellar Structures, and Photophysical Properties

Abstract

The first successful synthesis of conjugated rod–coil star block copolymer, (PF‐b‐P2VP)n, containing conjugated poly[2,7‐(9,9‐dihexylfluorene)] (PF), and coil‐like poly(2‐vinylpyridine) (P2VP) by combining a Suzuki coupling reaction and living anionic polymerization is reported. With increasing methanol content in THF/methanol mixtures (PF‐b‐P2VP)n symmetric star‐block copolymers maintain spherical micelles, but PF‐b‐P2VP asymmetric diblock copolymers vary from spherical micelles to vesicles. Both the absorption and emission spectra of PF‐b‐P2VP blue shift with increasing methanol content, suggesting an “H‐type” aggregation. However, (PF‐b‐P2VP)n star‐block exhibits no shift in absorption but a red shift in the emission spectra, indicating a different type of aggregation. These results suggest the significance of polymer architectures on microphase‐separated morphologies and photophysical properties. magnified image

Preparation and Characterization of Thermo-Responsive Rod-Coil Diblock Copolymers

“…The self-assembly of conjugated rod-coil block copolymers has been studied extensively towards novel structural, functional, and physical properties of supramolecular species [1,2,3]. The aggregation and microphase separation of such block copolymers driven by various novel functionalities of p–p interaction through solvent selection or rigid segmentation may result in various nanosized morphologies [4,5,6]. Different conjugated rod-coil block copolymers have been reported in the literature, including those of thiophene [7,8], phenylene [9,10,11], and quinolone [12,13].…”