One-Pot Preparation of 3D Nano- and Microaggregates via In Situ Nanoparticlization of Polyacetylene Diblock Copolymers Produced by ROMP

Self-Assembly of Copolymers Containing Crystallizable Blocks: Strategies and Applications

The self-assembly of copolymers containing crystallizable block in solution has received increasing attentions in the past few years. Various strategies including crystallization-driven self-assembly (CDSA) and polymerization-induced CDSA (PI-CDSA) have been widely developed. Abundant self-assembly morphologies were captured and advanced applications have been attempted. In this review, the synthetic strategies including the mechanisms and characteristics are highlighted, the survey on the advanced applications of crystalline nano-assemblies are collected. This review is hoped to depict a comprehensive outline for self-assembly of copolymers containing crystallizable block in recent years and to prompt the development of the self-assembly technology in interdisciplinary field. This article is protected by copyright. All rights reserved.

Synchronous Preparation of Length-Controllable 1D Nanoparticles via Crystallization-Driven In Situ Nanoparticlization of Conjugated Polymers

Precise size control of semiconducting nanomaterials from polymers is crucial for optoelectronic applications, but the low solubility of conjugated polymers makes this challenging. Herein, we prepared length-controlled semiconducting one-dimensional (1D) nanoparticles by synchronous self-assembly during polymerization. First, we succeeded in unprecedented living polymerization of highly soluble conjugated poly(3,4-dihexylthiophene). Then, block copolymerization of poly(3,4-dihexylthiophene)-block-polythiophene spontaneously produced narrow-dispersed 1D nanoparticles with lengths from 15 to 282 nm according to the size of a crystalline polythiophene core. The key factors for high efficiency and length control are a highly solubilizing shell and slow polymerization of the core, thereby favoring nucleation elongation over isodesmic growth. Combining kinetics and high-resolution imaging analyses, we propose a unique mechanism called crystallization-driven in situ nanoparticlization of conjugated polymers (CD-INCP) where spontaneous nucleation creates seeds, followed by seeded growth in units of micelles. Also, we achieved "living" CD-INCP through a chain-extension experiment. We further simplified CD-INCP by adding both monomers together in one-shot copolymerization but still producing length-controlled nanoparticles.

Crosslinked Polydicyclopentadiene Nanoparticles via Ring-Opening Metathesis Polymerization-Induced Self-Assembly Approach

In this communication, the preparation of crosslinked polydicyclopentadiene (PDCPD) nanoparticles via ring-opening metathesis polymerization (ROMP)-induced self-assembly approach is reported. For the ROMPs, the macromolecular chain transfer agents (Macro-CTAs) are synthesized via the ring-opening polymerization (ROP) of ε-caprolactone (CL) with cis-2-butene-1,4-diol as the initiator. The ROMPs are performed with chloroform, tetrahydrofuran, toluene, 1,4-dioxane, and N,N-dimethylacetamide as the solvents, respectively, which are catalyzed with Grubbs second generation catalyst. It is found that the crosslinked PDCPD nanoparticles are obtained with spherical, cylindrical to planar morphologies, depending on the molecular weights of Macro-CTAs, the concentrations of DCPD and the natures of solvents. The polymerization induced self-assembly (ROMPISA) by the use of a non-norbornene-based macromolecular chain transfer agent provides a new and efficient approach to prepare crosslinked polymer nanoparticles.

Ionic polyacetylene with a unique nanostructure and high stability by metathesis cyclopolymerization-induced self-assembly

Conjugated ionic polyacetylene was synthesized by metathesis cyclopolymerization, and self-assembled into various nanostructures, which exhibited high thermal and oxidative stability.

Direct formation of nano-objects via in situ self-assembly of conjugated polymers

The development of the polymer self-assembly method “in situ nanoparticlization of conjugated polymers” is discussed in this Perspective.

Room temperature synthesis of block copolymer nano-objects with different morphologies via ultrasound initiated RAFT polymerization-induced self-assembly (sono-RAFT-PISA)

The first room temperature synthesis of diblock copolymer nano-objects with different morphologies using ultrasound (990 kHz) initiated reversible addition-fragmentation chain transfer PISA (sono-RAFT-PISA) in aqueous system.

Polymerization techniques in polymerization-induced self-assembly (PISA)

The development of controlled/“living” polymerization greatly stimulated the prosperity of the fabrication and application of block copolymer nano-objects.

Conformation of Tunable Nanocylinders: Up to Sixth-Generation Dendronized Polymers via Graft-Through Approach by ROMP

Well-defined dendronized polymers (denpols) bearing high-generation dendron are attractive nano-objects as high persistency provides distinct properties, contrast to the random coiled linear polymers However, their syntheses via graft-through approach have been very challenging due to their structural complexity and steric hindrance retarding polymerization. Here, we report the first example of the synthesis of poly(norbornene) (PNB) containing ester dendrons up to the sixth generation (G6) by ring-opening metathesis polymerization. This is the highest generation ever polymerized among dendronized polymers prepared by graft-through approach, producing denpols with molecular weight up to 1960 kg/mol. Combination of size-exclusion chromatography, light scattering, and neutron scattering allowed a thorough structural study of these large denpols in dilute solution. A semiflexible cylinder model was successfully applied to represent both the static and dynamic experimental quantities yielding persistent length (l p), cross-sectional radius (R cs), and contour length (L). The denpol persistency seemed to increase with generation, with l p reaching 27 nm (Kuhn length 54 nm) for PNB-G6, demonstrating a rod-like conformation. Poly(endo-tricycle[4.2.2.0]deca-3,9-diene) (PTD) denpols exhibited larger persistency than the PNB analogues of the same generation presumably due to the higher grafting density of the PTD denpols. As the dendritic side chains introduce shape anisotropy into the denpol backbone, future work will entail a study of these systems in the concentrated solutions and melts.

Ring-opening metathesis polymerization-induced self-assembly (ROMPISA)

Ring-opening metathesis polymerization-induced self-assembly (ROMPISA) has expanded the preparation of PISA nano-objects beyond radical polymerization approaches. In this highlight article, we summarize current advances and existing challenges in ROMPISA methodologies.

Importance of choosing the right polymerization method for in situ preparation of semiconducting nanoparticles from the P3HT block copolymer

Precise control on synthesis of P3HT-b-PT at the molecular level promotes more controlled in situ nanoparticlization to give more well-defined nanostructures.

Preparing DNA-mimicking multi-line nanocaterpillars via in situ nanoparticlisation of fully conjugated polymers

A unique hierarchical evolution from single-line nanocaterpillars to multi-line nanocaterpillars was demonstrated by in situ nanoparticlisation of fully conjugated poly(2,5-dihexyloxy-1,4-phenylene)-block-poly(3-methylthiophene).