Ethylene Polymerization‐Induced Self‐Assembly (PISA) of Poly(ethylene oxide)‐block‐polyethylene Copolymers via RAFT

Abstract

Poly(ethylene oxide) (PEO) with dithiocarbamate chain ends (PEO–SC(=S)−N(CH3)Ph and PEO–SC(=S)−NPh2, named PEO‐1 and PEO‐2, respectively) were used as macromolecular chain‐transfer agents (macro‐CTAs) to mediate the reversible addition–fragmentation chain transfer (RAFT) polymerization of ethylene in dimethyl carbonate (DMC) under relatively mild conditions (80 °C, 80 bar). While only a slow consumption of PEO‐1 was observed, the rapid consumption of PEO‐2 led to a clean chain extension and the formation of a polyethylene (PE) segment. Upon polymerization, the resulting block copolymers PEO‐b‐PE self‐assembled into nanometric objects according to a polymerization‐induced self‐assembly (PISA).

Rapid formation and real-time observation of micron-sized conjugated nanofibers with tunable lengths and widths in 20 minutes by living crystallization-driven self-assembly

“…cores which then, were not detectable in 1 H NMR analysis. [38][39][40]45 To better characterize the BCPs by NMR, we attempted various deuterated solvents such as benzene, 1,4-dioxane, chlorobenzene, and o-dichlorobenzene to dissolve both blocks, but still chloroform was the best solvent for the BCPs (Fig. S3 46,47 To further promote self-assembly, we aged BCP solutions (1 g L À1 chloroform) at 25 C for 1 d, and found an overall increase in D h , up to 700 nm under identical conditions, except for P1 50b-P2 10 ( Fig.…”

Polymerizations by RAFT: Developments of the Technique and Its Application in the Synthesis of Tailored (Co)polymers

“…Since then it has been demonstrated by different groups that switchable RAFT agents such as N ‐(4‐pyridinyl)‐ N ‐methyldithiocarbamates, could be used to prepare block copolymers under different polymerization regimes (bulk, solution, emulsion, PISA, etc.). [ 42–46 ] Later in 2016, Moad and co‐workers developed a class of dithiocarbamate CTAs with a balanced activity toward both monomer classes without the need of switching making the synthesis of poly(MAM)‐ block ‐poly(LAM)s possible. [ 47 ]…”

“…The crystalline nature of the PE segment induced a variety of morphologies including worms. [ 44 ] Another example of a previously unreported block copolymer is the synthesis of an all‐poly(ionic liquid) block copolymer nanoparticles with various morphologies by aqueous RAFT‐PISA relying on the use of isomeric ionic liquid monomers (where one isomer is hydrophilic and the other hydrophobic) giving rise to macromolecular building blocks with antagonistic solution behavior in water. [ 112 ] Among the latest work reported are the (co) polymerizations of styrene via PISA.…”

Light-intensity switch enabled nonsynchronous growth of fluorinated raspberry-like nanoparticles

“…1 Among them, raspberry-like (RB) particles have gained considerable attention due to their surface roughness, large surface areas and high level of scattering ratios, 2,3 leading to applications such as drug delivery, 4 catalyst supports, 5 photonic materials 6 and superhydrophobic coatings. 7 While reversible-deactivation radical polymerization (RDRP) has enabled the generation of polymeric particles with various morphologies [8][9][10] ranging from spheres, worms, and vesicles to ordered inverse mesophases through the operationally simple polymerization induced self-assembly (PISA) pathway, [11][12][13][14][15] it still remains challenging to generate RB particles based on PISA. Conventionally, RB particles have been obtained via the combination of small corona and large core particles via physical or chemical interactions, 16,17 as well as emulsion polymerization.…”