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Fiber‐like π‐conjugated nanostructures are important components of flexible organic electronic and optoelectronic devices. To broaden the range of potential applications, one needs to control not only the length of these nanostructures, but the introduction of diverse functionality with spatially selective control. Here we report the synthesis of a crystalline‐coil block copolymer of oligo(p‐phenylenevinylene)‐b‐poly(2‐vinylpyridine) (OPV5‐b‐P2VP44), in which the basicity and coordinating/chelating ability of the P2VP segment provide a landscape for the incorporation of a variety of functional inorganic NPs. Through a self‐seeding strategy, we were able to prepare monodisperse fiber‐like micelles of OPV5‐b‐P2VP44 with lengths ranging from 50 to 800 nm. Significantly, the exposed two ends of OPV core of these fiber‐like micelles remained active toward further epitaxial deposition of OPV5‐b‐PNIPAM49 and OPV5‐b‐P2VP44 to generate uniform A‐B‐A and B‐A‐B‐A‐B segmented block comicelles with tunable lengths for each block. The P2VP domains in these (co‐)micelles can be selectively decorated with inorganic and polymeric nanoparticles as well as metal oxide coatings, to afford hybrid fiber‐like nanostructures. This work provides a versatile strategy toward the fabrication of narrow length dispersity continuous and segmented π‐conjugated OPV‐containing fiber‐like micelles with the capacity to be decorated in a spatially selective way with varying functionalities. [ABSTRACT FROM AUTHOR]

Crystallization-driven self-assembly (CDSA) of block copolymers (BCPs) with a crystallizable core-forming oligo(p -phenylenevinylene) (OPV) segment can be a powerful strategy for the preparation of uniform fiber-like nanostructures containing a π-conjugated core with controlled dimension and composition. However, the self-assembly landscape can be complex, and our understanding of the nucleation and growth processes in the CDSA of BCPs with a crystalline π-conjugated segment is limited. We used fluorescence spectroscopy and 1H NMR to follow the self-assembly of oligo(p -phenylenevinylene)- b -poly(N -isopropyl acrylamide) (OPV 5 - b -PNIPAM 49), a typical π-conjugated-coil BCP, as solution of the BCP in ethanol is cooled from 80 °C to 23 °C and allowed to age, µDSC to monitor the crystallization exotherm, and DLS and TEM to follow micelle growth. We see a striking difference in the experiments that monitor unimer in solution comparing to those that monitor micelle growth. We see nearly complete disappearance of unimer within 30 min upon cooling. In contrast, the micelles continue to grow, increasing in length by a factor of ten over the next several hours. We are able to exclude growth by end-to-end coupling. We propose a self-assembly mechanism in which short semi-crystalline rod-like micelles form upon cooling, accompanied by small amorphous aggregates. Unimers that dissociate from these aggregates subsequently deposit on the growing ends of the core-crystalline micelles. We also find that the length of the PNIPAM block affects the elongation kinetics of OPV 5 - b -PNIPAM. [ABSTRACT FROM AUTHOR]

We report the preparation of a series of fiber-like micelles of narrow length distribution with an oligo(p-phenylenevinylene) (OPV)-core and a poly(N-isopropylacrylamide) (PNIPAM) corona via two different crystallization-driven self-assembly (CDSA) strategies. The average length L n of these micelles can be varied up to 870 nm by varying the temperature in self-seeding experiments. In addition, seeded growth was employed not only to prepare uniform micelles of controlled length, but also to form fiber-like A-B-A triblock comicelles with an OPV-core. [ABSTRACT FROM AUTHOR]