Interplay of Vesicle and Lamellae Formation in an Amphiphilic Polyfluorene-b-polythiophene All-Conjugated Diblock Copolymer at the Air−Water Interface

Abstract

Interfacial behavior and surface morphology of an amphiphilic, all-conjugated rod-rod diblock copolymer, poly [9,9-bis(2-ethylhexyl)fluorene]-b-poly [3-(6-diethylphosphonatohexyl)thiophene] or PF2/6-b-P3PHT, were investigated by a combination of Langmuir-Blodgett (LB) techniques, optical spectroscopy, and atomic force microscopy (AFM). For the PF2/6-b-P3PHT diblock copolymer aggregates, well-defined gas, liquid-expanded, liquid-condensed, and solid states were observed at the air-water interface. The backbones of the polar P3PHT blocks exhibited an edge-on arrangement which is driven by the pendant alkyl chains with the polar phosphate groups; i.e., the polymer main chain orients parallel to the air/water interface with the planes of the thiophene rings in vertical orientation (edge-on). For comparison of the optical properties, three different LB films (transferred at surface pressures of 5, 15, and 50 mN/m), spin-or drop-cast films, and solutions were investigated. Spectral shifts and intensity changes of UV-vis absorption and photoluminescence emission of the films were correlated to changes of the surface morphology. The emission properties after excitation into the higher-bandgap PF2/6 absorption band were governed by both Fo ¨rster resonance energy transfer (FRET) and conformational changes within the P3PHT block. The AFM images illustrate the formation of vesicular species and their transition into a monolayer lamellar phase upon increased surface pressure and a correlation of the optical properties and aggregation state at the air/water interface.

In Situ Fabricating One-Dimensional Donor–Acceptor Core–Shell Hybrid Nanobeams Network Driven by Self-Assembly of Diblock Copolythiophenes

“…31 Earlier work on amphiphilic rod−rod diblock copolymers and their aggregation in mixtures of selective and nonselective solvents behavior was also processed in previous reports of Scherf. 33,34 A crucial requirement for high performance device was providing an efficient way to control the ordering of H4T1 amphiphilic block polymers with broadening optical absorbance in solid state. Thus, the optical property of H4T1 diblock copolymer in solid state was also studied in 100 nm thickness films, spin-coated on quartz and casted from pure DCB and DCB/CH 3 OH blended solutions with 16:1, 8:1, 4:1 volume ratios.…”

Polycondensation

“…Scherf and co-workers initially produced the all-conjugated rod-rod block copolymers, including polyfluorene segments (15)(16)(17)(18)(19), reviewed elsewhere (20). In the preceding section, a new concept of controlled condensation polymerization was introduced for precisely controlling the molecular weights and molecular weight distributions of polycondensates.…”

“…The TFT hole mobility of 13 was as high as 2.0 × 10 − 2 cm 2 V − 1 s − 1 , which is comparable to the pristine P3HT. Many other examples (15)(16)(17)(18)(19)(20)(21) have subsequently emerged in the literature (28)(29)(30)(31)(32)(33)(34). For instance, new all-conjugated block copolymers with different main chains of P3HT-b-poly(2,5-dihexyloxy-p-phenylene) (22) (35) and poly(2,5dihexyloxy-p-phenylene)-b-poly(N-hexylpyrrole) (23) (36) could also be synthesized by the sequential GRIM polymerization.…”

Nanowire Shish‐Kebab Structures and Molecular Orientation Control of All‐Conjugated Diblock Copolymers

“…In other words, nanocrystals with a preferential face-on orientation with (010) planes parallel to the substrate are beneficial for charge transport along the vertical direction. [20][21][22][23][24][25][26][27][28] However, with respect to all-conjugated diblock copolymers, Abstract: Herein we propose a facile strategy to prepare nanowires and nanowire "shish-kebab" (NWSK) structures by controlling the crystallization behavior of all-conjugated rod-rod diblock copolymers poly[(p-phenylene)-block-(3-hexylthiophene)]s (PPPb-P3HT (BmTn)) with varying main chain lengths. BCPs are known to spontaneously self-organize into well-defined microphase-separated patterns at the nanoscale driven by factors such as immiscibility and the crystallization difference between the blocks.…”

“…Thus, several works have been published on the design and synthesis of all-conjugated thiophenebased rod-rod block copolymers because of their unique and attractive combination of highly ordered nanostructure formation and outstanding charge-transporting mobility. [20][21][22][23][24][25][26][27][28] However, with respect to all-conjugated diblock copolymers, Abstract: Herein we propose a facile strategy to prepare nanowires and nanowire "shish-kebab" (NWSK) structures by controlling the crystallization behavior of all-conjugated rod-rod diblock copolymers poly[(p-phenylene)-block-(3-hexylthiophene)]s (PPPb-P3HT (BmTn)) with varying main chain lengths. Depending on the block length and ratio (i.e., PPP/P3HT, abbreviated as B/T), nanowires with low B/T ratios (copolymers with long P3HT blocks; B8T32 and B14T34) and…”