Recently, polymerization-induced self-assembly (PISA) has become widely recognized as a robust and efficient route to produce block copolymer nanoparticles of controlled size, morphology, and surface chemistry. Several reviews of this field have been published since 2012, but a substantial number of new papers have been published in the last three years. In this Perspective, we provide a critical appraisal of the various advantages offered by this approach, while also pointing out some of its current drawbacks. Promising future research directions as well as remaining technical challenges and unresolved problems are briefly highlighted.

http://pubs.acs.org/doi/pdf/10.1021/acs.macromol.5b02602

A Critical Appraisal of RAFT-Mediated Polymerization-Induced Self-Assembly.

This Perspective describes the recent developments of polymerization-induced self-assembly of amphiphilic block copolymers based on controlled/living free-radical polymerization (CRP) in water. This method relies on the use of a hydrophilic living polymer precursor prepared via CRP that is extended with a hydrophobic second block in an aqueous environment. The process thus leads to amphiphilic block copolymers that self-assemble in situ into self-stabilized nano-objects in the frame of an emulsion or dispersion polymerization process. Depending on the nature and the structure of the so-formed copolymer, not only spherical particles can be achieved but also all morphologies that can be found in the phase diagram of an amphiphilic block copolymer in a selective solvent. This paper focuses mainly on aqueous emulsion or dispersion polymerization and gives an overview of the CRP techniques used, the general conditions, and the morphologies obtained.

Polymerization-Induced Self-Assembly: From Soluble Macromolecules to Block Copolymer Nano-Objects in One Step

This review is an extensive update to the comprehensive review
on controlled/living radical polymerization (CLRP) in
dispersed systems published in 2008.

Controlled/Living Radical Polymerization in Dispersed Systems: An Update

After a brief history that positions polymerization-induced self-assembly (PISA) in the field of polymer chemistry, this Review will cover the fundamentals of the PISA mechanism. Furthermore, this Review will also give an overview of some of the features and limitations of RAFT-mediated PISA in terms of the choice of the components involved, the nature of the nanoobjects that can be obtained and how the syntheses can be controlled, as well as some potential applications.

https://hal.archives-ouvertes.fr/hal-03085063/document

RAFT‐mediated polymerization‐induced self‐assembly

We report the synthesis of anionic sterically stabilized diblock copolymer nanoparticles via polymerization-induced self-assembly using a RAFT aqueous dispersion polymerization formulation. The anionic steric stabilizer is a macromolecular chain-transfer agent (macro-CTA) based on poly(potassium 3-sulfopropyl methacrylate) (PKSPMA), and the hydrophobic core-forming block is based on poly(2-hydroxypropyl methacrylate) (PHPMA). The effect of varying synthesis parameters such as the salt concentration, solids content, relative block composition, and anionic charge density has been studied. In the absence of salt, self-assembly is problematic when using a PKSPMA stabilizer because of lateral repulsion between highly charged anionic chains. However, in the presence of added salt this problem can be overcome by reducing the charge density within the coronal stabilizer layer by either (i) statistically copolymerizing the KSPMA monomer with a nonionic comonomer (2-hydroxyethyl methacrylate, HEMA) or (ii) using a ...

Anionic polyelectrolyte-stabilized nanoparticles via RAFT aqueous dispersion polymerization.

The SG1-mediated copolymerization of methacrylic acid and a small percentage of sodium 4-styrenesulfonate was performed in water solution at 76 °C, using BlocBuilder as an alkoxyamine initiator under acidic conditions. Unexpectedly, these conditions, which could be considered as rather unfavorable due to the instability of SG1 in acidic water, led to very good results in term of polymerization kinetics and control over polymer chain growth. It appeared that low temperature and short reaction time were the key parameters to maintain a good living character to the chains as evaluated by in situ 31P NMR. The aqueous system was then used directly as the polymerization medium for the emulsion copolymerization of methyl methacrylate and styrene performed at 90 °C. This one-pot procedure led to the synthesis of amphiphilic block copolymers that self-assembled into stable core–shell nanoparticles.

Nitroxide-Mediated Copolymerization of Methacrylic Acid and Sodium 4-Styrenesulfonate in Water Solution and One-Pot Synthesis of Amphiphilic Block Copolymer Nanoparticles

1H DOSY NMR provides a simple and convenient method to determine both the molecular weight and the solution properties of poly(N-acryloylmorpholine) (PNAM) in various organic and aqueous solvents. This technique is used to measure the average diffusion coefficient DPNAM of a library of PNAM samples of increasing molecular weights synthesized by reversible addition fragmentation chain transfer controlled radical polymerization. In all solvents, the highly linear relationship between Log DPNAM and Log Mw yields calibration curves that can be used for the reliable determination of the molecular weight of various types of PNAM samples. In addition, the slope of the calibration curves can be considered as the Flory exponent δ characterizing the solvent–polymer interaction. The measurements show that CDCl3 and D2O are theta solvents for PNAM and that δ slightly decreases in phosphate buffer solution (PBS), pH 7.4, and upon addition of MeOD in D2O.

1H DOSY NMR Determination of the Molecular Weight and the Solution Properties of Poly(N-acryloylmorpholine) in Various Solvents

Fluorescent gold nanoparticles with chain-end grafted RAFT copolymers: influence of the polymer molecular weight and type of chromophore

Correction for 'Light-induced in situ chemical activation of a fluorescent probe for monitoring intracellular G-quadruplex structures' by Marco Deiana et al., Nanoscale, 2021, 13, 13795-13808, https://doi.org/10.1039/D1NR02855C.

/pdf/correction-light-induced-in-situ-chemical-activation-of-a-2hmybc83.pdf

Cécile Chamignon

Papers

Nitroxide-Mediated Copolymerization of Methacrylic Acid and Sodium 4-Styrenesulfonate in Water Solution and One-Pot Synthesis of Amphiphilic Block Copolymer Nanoparticles

1H DOSY NMR Determination of the Molecular Weight and the Solution Properties of Poly(N-acryloylmorpholine) in Various Solvents

Fluorescent gold nanoparticles with chain-end grafted RAFT copolymers: influence of the polymer molecular weight and type of chromophore

Correction: Light-induced in situ chemical activation of a fluorescent probe for monitoring intracellular G-quadruplex structures.