Simple Preparation of Various Nanostructures via in Situ Nanoparticlization of Polyacetylene Blocklike Copolymers by One-Shot Polymerization

Abstract

Previously, we reported the one-pot synthesis of polyacetylene (PA) diblock copolymers which formed various nanostructures via the in situ nanoparticlization of conjugated polymers (INCP), using a two-step protocol based on sequential monomer addition. Herein, we report a much simpler one-shot method for nanostructure formation by the synthesis of PA blocklike copolymers. The blocklike copolymers could be prepared by the one-shot ROMP of comonomers with large differences in their reactivities because the monomers that formed the first block, namely norbornene (NB) derivatives or endo-tricyclo[4.2.2.0]deca-3,9-diene (TD) derivatives, polymerized much faster than the monomers that formed the second PA block, cyclooctatetraene (COT). Owing to their blocklike microstructures, the copolymers formed various nanostructures such as nanospheres, nanocaterpillars, and nanoaggregates depending on the chemical structures of the soluble shell polymers and feed ratio of COT, which formed the insoluble PA core. Using dynamic light scattering (DLS) and atomic force microscopy (AFM), it was observed that the nanostructures produced from the blocklike copolymers were essentially the same as those produced from the block copolymers synthesized by conventional sequential monomer addition. The blocklike microstructures of the copolymers formed by one-shot ROMP were further supported by an in situ 1H NMR kinetic experiment and UV/vis spectroscopy. From these results, we were able to confirm that the ROMP of TD and COT produced near-perfect block copolymers. Furthermore, the 1H NMR spectra of the one-shot copolymerization provided insights into the INCP process.

Spontaneous evolution of nanostructures by light‐driven growth of micelles obtained from in situ nanoparticlization of conjugated polymers

“…Nevertheless, BCP‐II did not show further evolution to higher dimensional nanostructures after aging. Consequently, we modified our strategy to changing the structure of the monomer of the first block to alter the core–shell interaction …”

“…Recent reports suggested that the backbone of poly( endo ‐tricyclo[4.2.2.0]deca‐3,6‐diene) (PTD) was more rigid than that of PNB . This affected the INCP behavior because BCPs containing the PTD shell and PA core allowed for enhanced π‐π interaction, resulting in the formation of three‐dimensional aggregates . By combining the effects of the rigid shell and the time‐dependent expansion of the PCPV core, we designed and prepared another conjugated polymer that would also undergo spontaneous mesoscopic evolution under light by living ROMP and cyclopolymerization.…”

“…Again, in order for these conjugated polymers to undergo self‐assembly, extra postsynthetic treatments were necessary. To address this drawback, our group developed a new strategy to achieve spontaneous formation of nanostructures during polymerization, which we termed as in situ nanoparticlization of conjugated polymers (INCP) . Typically, conjugated polymers without side chains are insoluble in all solvents due to strong π‐π interactions; ironically, this became the crucial driving force for the INCP process.…”

The utilization of post-synthetic modification in opto-electronic polymers: an effective complementary approach but not a competitive one to the traditional direct polymerization process

“…[56][57][58][59][60] Generally, disubstituted PAs possess very good thermal stability (no molecular weight change detectable after annealing in air at 120 °C for 20 h), and efficiently strong fluorescence without photo-bleaching. [56][57][58][59][60] Generally, disubstituted PAs possess very good thermal stability (no molecular weight change detectable after annealing in air at 120 °C for 20 h), and efficiently strong fluorescence without photo-bleaching.…”

Reactive and Functional Nanoobjects by Polymerization‐Induced Self‐Assembly

“…When they are insoluble (i.e., when PISA starts from two immiscible phases), the mechanism is based on surfactant‐free emulsion polymerization. The underpinning polymerization mechanism is typically based on an RDRP technique—mostly reversible addition–fragmentation chain‐transfer (RAFT) polymerization but also nitroxide‐mediated polymerization (NMP) and to a lower extent copper‐mediated RDRP—but a few examples based on further living polymerization mechanisms such as ring‐opening metathesis polymerization (ROMP) and anionic polymerization, or even on non‐living radical polymerization, have appeared.…”