Modern Trends in Polymerization-Induced Self-Assembly

Zhang S., Li R., An Z.

AbstractPolymerization‐induced self‐assembly (PISA) combines polymerization and in situ self‐assembly of block copolymers in one system and has become a widely used method to prepare block copolymer nanoparticles at high concentrations. The persistence of polymers in the environment poses a huge threat to the ecosystem and represents a significant waste of resources. There is an urgent need to develop novel chemical approaches to synthesize degradable polymers. To meet with this demand, it is crucial to install degradability into PISA nanoparticles. Most recently, degradable PISA nanoparticles have been synthesized by introducing degradation mechanisms into either shell‐forming or core‐forming blocks. This Minireview summarizes the development in degradable block copolymer nanoparticles synthesized by PISA, including shell‐degradable, core‐degradable, and all‐degradable nanoparticles. Future development will benefit from expansion of polymerization techniques with new degradation mechanisms and adaptation of high‐throughput approaches for both PISA syntheses and degradation studies.

Cai J., Wang X., Liu Y., Luo C., Lu X., Cai Y.

Bowman J.I., Eades C.B., Vratsanos M.A., Gianneschi N.C., Sumerlin B.S.

AbstractPolymerization‐induced self‐assembly (PISA) is a powerful technique for preparing block copolymer nanostructures. Recently, efforts have been focused on applying photochemistry to promote PISA due to the mild reaction conditions, low cost, and spatiotemporal control that light confers. Despite these advantages, chain‐end degradation and long reaction times can mar the efficacy of this process. Herein, we demonstrate the use of ultrafast photoiniferter PISA to produce polymeric nanostructures. By exploiting the rapid photolysis of xanthates, near‐quantitative monomer conversion can be achieved within five minutes to prepare micelles, worms, and vesicles at various core‐chain lengths, concentrations, or molar compositions.

Kim K.H., Huh Y., Song I., Ryu D.Y., Son J.G., Bang J.

AbstractA perspective is presented on recent developments in block copolymers (BCPs), capable of forming sub‐10 nm nanostructures and bottlebrush block copolymers (BBCPs), capable of forming supra‐100 nm nanostructures. Over the last few decades, BCP research has emphasized pattern miniaturization for application in next‐generation lithography tools in the semiconductor industry. The first part focuses on the recent efforts that investigated high‐χ linear BCPs evolved from conventional poly(styrene‐b‐methyl methacrylate) (PS‐b‐PMMA) pairs. Recently, novel BCP structures capable of forming nanostructures with significant periodicities for controlling visible light have gained considerable attention. The second part reviews the literature on BBCPs that exhibit the potential to create supra‐100 nm nanostructures. Finally, the future aspect on BCP lithography is discussed.

Chen Y., Tan J., Shen L.

AbstractOver the past decade, polymerization‐induced self‐assembly (PISA) has fully proved its versatility for scale‐up production of block copolymer nanoparticles with tunable sizes and morphologies; yet, there are still some limitations. Recently, seeded PISA approaches combing PISA with heterogeneous seeded polymerizations have been greatly explored and are expected to overcome the limitations of traditional PISA. In this review, recent advances in seeded PISA that have expanded new horizons for PISA are highlighted including i) general considerations for seeded PISA (e.g., kinetics, the preparation of seeds, the selection of monomers), ii) morphological evolution induced by seeded PISA (e.g., from corona‐shell‐core nanoparticles to vesicles, vesicles‐to‐toroid, disassembly of vesicles into nanospheres), and iii) various well‐defined nanoparticles with hierarchical and sophisticated morphologies (e.g., multicompartment micelles, porous vesicles, framboidal vesicles, AXn‐type colloidal molecules). Finally, new insights into seeded PISA and future perspectives are proposed.This article is protected by copyright. All rights reserved

Deng Z., Sun Y., Guan S., Chen A.

AbstractPolymerization‐induced self‐assembly incorporating liquid crystallization, as a polymerization‐induced hierarchical self‐assembly (PIHSA) method to produce polymeric particles with anisotropic morphologies facilely and efficiently, has drawn wide attention recently. However, the means of regulating the morphologies of liquid crystalline (LC) polymer assemblies still need to be explored. Herein, we present a route to fabricate the twisted ribbons via PIHSA containing azobenzene based on poor reversible addition‐fragmentation chain transfer (RAFT) control, called as poorly controlled PIHSA. Cyano‐4‐(dodecylsulfanylthiocarbonyl)sulfanyl pentanoic acid‐2‐(2‐pyridyldithio) ethyl ester was used as the RAFT agent with poor controllability, and the morphological evolution from ribbons to twisted ribbons could be observed in the corresponding PIHSA system. The formation mechanism of the twisted ribbons was studied systematically and the broad molecular weight distribution was considered to be the decisive factor. Moreover, the supramolecular chirality induced by symmetry breaking was also related to the twist of the ribbons. This study enriches the methods of controlling the morphologies of LC polymer particles and is helpful for further clarifying the mechanism of PIHSA.This article is protected by copyright. All rights reserved

György C., Armes S.P.

AbstractIt is well‐known that polymerization‐induced self‐assembly (PISA) is a powerful and highly versatile technique for the rational synthesis of colloidal dispersions of diblock copolymer nanoparticles, including spheres, worms or vesicles. PISA can be conducted in water, polar solvents or non‐polar media. In principle, the latter formulations offer a wide range of potential commercial applications. However, there has been just one review focused on PISA syntheses in non‐polar media and this prior article was published in 2016. The purpose of the current review article is to summarize the various advances that have been reported since then. In particular, PISA syntheses conducted using reversible addition‐fragmentation chain‐transfer (RAFT) polymerization in various n‐alkanes, poly(α‐olefins), mineral oil, low‐viscosity silicone oils or supercritical CO2 are discussed in detail. Selected formulations exhibit thermally induced worm‐to‐sphere or vesicle‐to‐worm morphological transitions and the rheological properties of various examples of worm gels in non‐polar media are summarized. Finally, visible absorption spectroscopy and small‐angle X‐ray scattering (SAXS) enable in situ monitoring of nanoparticle formation, while small‐angle neutron scattering (SANS) can be used to examine micelle fusion/fission and chain exchange mechanisms.

Zhang J., Zhou P., Shi B., Li P., Wang G.

Luo C., Wang X., Liu Y., Cai J., Lu X., Cai Y.

Gu Q., Li H., Cornel E.J., Du J.

Polymerization-induced self-assembly (PISA) is a powerful tool to prepare dispersed block copolymer nanoparticles with various morphologies in a range of solvents. This method is based on the chain extension of a soluble homopolymer with a monomer that forms an insoluble second block. Once a critical chain length of this second block is achieved, polymer aggregation into nanoparticles occurs in situ. Various nanoparticle morphologies can be accurately targeted by adjusting the degree of polymerization (DP) of either the stabilizer block or core-forming block and the total solids content (or final polymer concentration). In this Perspective, we give a brief but comprehensive introduction to this nanoparticle preparation method. Afterward, we discuss emerging PISA methods that push the boundaries of this technology. Some of these new methods utilize polymer insolubility (polymer-solvent interactions) as a self-assembly driving force, and these are discussed first; afterward, recently discovered PISA formulations where in situ self-assembly relies on polymer-polymer interactions are discussed. Examples of such polymer-polymer interactions include hydrogen bonds, electrostatic effects, chirality, and crystallization. The current state and limitations of PISA are discussed in the final section of this Perspective. Additionally, we provide insights on how the current limitations of PISA can be overcome with the aim of making PISA nanoparticle synthesis more applicable for a broad range of audiences with higher nanoparticle demands.

Rigo E., Ladmiral V., Caillol S., Lacroix-Desmazes P.

Vegetable oils and lipids, terpenes, lignin derivatives, carbohydrates, and proteins are used as biomass feedstock to prepare new bio-based monomers for radical polymerization in aqueous dispersed media, producing bio-based latexes.

Xu Q., Yu C., Jiang L., Wang Y., Liu F., Jiang W., Zhou Y.

Ikkene D., Six J., Ferji K.

Polymerization-induced self-assembly (PISA) is an emerging platform technology offering many advantages to produce polymeric nano-objects compared to the solvent switch methods. Aqueous dispersion reversible addition fragmentation chain transfer PISA (aqueous dispersion RAFT PISA) has progressively won over many research groups due to its green chemical process and amazing efficiency to produce a wide range of morphologies. This review summarizes the recent works reported in the literature on the aqueous dispersion RAFT PISA. After a general introduction on the PISA process, exhaustive lists of the different RAFT activation techniques, the hydrophilic steric stabilizers, and the monomers used are shown and discussed. Our objective is to provide an overview for experts and a toolbox for nonexperts that aim to explore this robust and efficient route to produce block copolymer-based nano-objects for a specific application.

Scheutz G.M., Bowman J.I., Mondal S., Rho J.Y., Garrison J.B., Korpanty J., Gianneschi N.C., Sumerlin B.S.

Clothier G.K., Guimarães T.R., Strover L.T., Zetterlund P.B., Moad G.

Ivanova E.A., Vlasov E.I., Bekanova M.Z., Simenido G.A., Plutalova A.V., Kozhunova E.Y., Kuznetsova E.K., Golubeva E.N., Chernikova E.V.

Well-defined stimuli-responsive linear polymers of <em>N</em>-isopropylacrylamide, its block and random copolymers have been synthesized <em>via</em> aqueous reversible addition-fragmentation chain transfer polymerization performed above low critical solution temperature of poly(<em>N</em>-isopropylacrylamide).

Kravchenko V.S., Gumerov R.A., Potemkin I.I.

Block copolymers have been known for more than a half-century. In contrast to their statistical counterparts, such macromolecules can form aggregates of various, well-defined shapes in solutions and at the interfaces. Meanwhile, due to a significant progress in polymer synthesis, gradient copolymers are gaining more and more interest as a potentially cheaper alternative to the simplest case of block structures – the diblock copolymers. Because of relative novelty of such macromolecules, the new properties of respective polymer systems are being continuously discovered. This review highlights the recent advances in the study of gradient and diblock copolymer assemblies in solution and at various interfaces and provides by a direct comparison of properties of the latter and the former.