RAFT polymerization of hydroxy-functional methacrylic monomers under heterogeneous conditions: effect of varying the core-forming block

Ratcliffe, Liam P. D.; Blanazs, Adam; Williams, Clive N.; Brown, Steven L.; Armes, Steven P.

doi:10.1039/c4py00203b

Cited by 58 publications

(82 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7b) and 30/170 (Fig. Reaction acceleration was observed by Armes, 54 in copolymerisation of a water-soluble monomer and a water-insoluble monomer using a water-soluble macro-CTA. Entirely different from that at 10/190, irradiation initiated simultaneous copolymerisation and AEAM reaction acceleration also occurred after 49%, 55% conversions.…”

Section: Dehydration Of Daam Units Was Probed By 1 H Nmr In D 2 Omentioning

confidence: 63%

The direct synthesis of interface-decorated reactive block copolymer nanoparticles via polymerisation-induced self-assembly

et al. 2015

View full text Add to dashboard Cite

Self-assembly of amphiphilic block copolymer in water suffers from the undesired encapsulation of hydrophobic reactive motifs in core-forming block, which deteriorates the performance as aqueous catalysts. This problem can be circumvented by polymerisation-induced self-assembly (PISA). Herein, we report a new strategy for one-pot synthesis of reactive block copolymer nanoparticles whose hydrophobic reactive motifs decorate surrounding core-shell interfaces. We demonstrate fast RAFT aqueous dispersion polymerisation of a commercial available specialty monomer, diacetone acrylamide (DAAM), under visible light irradiation at 25 o C. PISA is induced by polymerisation via sequentially dehydration, phase separation and reaction acceleration, and thus complete conversion in 30 min. Replacement of minimal DAAM by NH3 + -monomer induces slight hydration of the core-forming block, and thus a low polydispersity of resultant statistic-block copolymer. Moreover, simultaneous in situ self-assembly and chain growth favours adjustment of newly-added NH3 + -units outward to core-shell interfaces while the major DAAM units collapse to hydrophobic PISA-cores. Both lead to timely and selective self-assembly into the new reactive nanoparticles whose NH3 + -motifs decorate surrounding core-shell interfaces. These nanoparticles well suit fabrication of advanced nanoreactors whose hydrophobic dative metal centres decorate surrounding interfaces via simultaneous imine conversion and Zn(II)-coordination. Such PISA-nanostructures endow hydrophobic metal centres with huge and accessible specific surface area and are stabilized by water-soluble shells. Therefore, this strategy holds fascinating potentials for the fabrication of metalloenzyme-inspired aqueous catalysts.Enzyme inspired interface-decorated media-accessible reactive nanoparticles are now available via PISA by aqueous dispersion RAFT of commodity-DAAM with minimal NH 3 + -monomer.

show abstract

Section: Dehydration Of Daam Units Was Probed By 1 H Nmr In D 2 Omentioning

confidence: 63%

The direct synthesis of interface-decorated reactive block copolymer nanoparticles via polymerisation-induced self-assembly

et al. 2015

View full text Add to dashboard Cite

show abstract

“…In a very recent study on poly[GMA 60 ‐ b ‐(2‐hydroxyethyl methacrylate 50 ‐ co ‐4‐hydroxybutyl methacrylate 50 )], p[GMA 60 ‐ b ‐(HEMA 50 ‐ co ‐HBMA 50 )] with an inner block isomeric to pHPMA, gelation upon cooling from 20 °C to 5 °C in water (the opposite effect to pHPMA core particles) was observed . While the cause of this behavior (such as a “reverse” S‐to‐W transition upon cooling or change in worm length) is yet to be elucidated, this qualitative difference demonstrates the large potential of such nano‐objects and their temperature‐responsive dispersions in the smart materials arena.…”

Section: Temperature‐responsive Dispersion Pisa Nano‐objectsmentioning

confidence: 99%

Stimulus‐Responsive Nanoparticles and Associated (Reversible) Polymorphism via Polymerization Induced Self‐assembly (PISA)

Pei

Lowe

Roth

2016

Macromol. Rapid Commun.

118

131

View full text Add to dashboard Cite

"smart" materials rely on very distinct material responses on a macroscopic and/or microscopic level. This can be achieved by crafting stimulus-responsive polymers into nanostructured materials, including smart nanoparticles, which are receiving increasing attention specifically in the biomedical field. [2,3] Amphiphilic block copolymers are well-known to undergo self-directed assembly in selective solvents providing access to a range of soft matter nanoparticles [4][5][6][7] with applications in coatings, [8] electronics, [9] drug delivery, [10] and cancer therapy, [11,12] among others. Traditionally, the preparation of such nanoparticles has been accomplished by initial synthesis and molecular dissolution of well-defined parent copolymers which are subsequently "processed", often via time-consuming step-wise dialysis, to give the targeted nano-object. Another drawback of this well-established approach is the generally low concentration of the final copolymer nanoparticles (≤1.0 wt% is common) which limits industrial application and study of such nanoparticles in areas where high Polymerization-induced self-assembly (PISA) is an extremely versatile method for the in situ preparation of soft-matter nanoparticles of defined size and morphologies at high concentrations, suitable for large-scale production. Recently, certain PISA-prepared nanoparticles have been shown to exhibit reversible polymorphism ("shape-shifting"), typically between micellar, worm-like, and vesicular phases (order-order transitions), in response to external stimuli including temperature, pH, electrolytes, and chemical modification. This review summarises the literature to date and describes molecular requirements for the design of stimulus-responsive nano-objects. Reversible pH-responsive behavior is rationalised in terms of increased solvation of reversibly ionized groups. Temperature-triggered order-order transitions, conversely, do not rely on inherently thermo-responsive polymers, but are explained based on interfacial LCST or UCST behavior that affects the volume fractions of the core and stabilizer blocks. Irreversible morphology transitions, on the other hand, can result from chemical post-modification of reactive PISA-made particles. Emerging applications and future research directions of this "smart" nanoparticle behavior are reviewed.

show abstract

“…The presence of such species becomes increasingly more obvious and prevalent with increasing X n values of the NOEMA block with the final copolymer in the series having a measured M of 1.69. Though it is common to observe such high molecular weight impurities in block copolymerizations taken to near-quantitative conversion in RAFTDP, [27,34,48,49] as well as more common homogeneous systems, the relatively large amount of the impurity, especially at higher NOEMA block lengths, is in contrast to the behaviour of other aryl methacrylate monomers in ethanolic RAFTDP formulations. This result suggests that NOEMA may not be a particularly useful substrate in such systems if the target is to prepare well-defined block copolymers as well as specific soft matter nano objects.…”

Section: Resultsmentioning

confidence: 89%

Ethanolic RAFT Dispersion Polymerization of 2-(Naphthalen-2-yloxy)ethyl Methacrylate and 2-Phenoxyethyl Methacrylate with Poly[2-(dimethylamino)ethyl Methacrylate] Macro-Chain Transfer Agents

2015

View full text Add to dashboard Cite

The ethanolic reversible addition-fragmentation chain transfer dispersion polymerization (RAFTDP), at 21 wt-%, of 2-(naphthalen-2-yloxy)ethyl methacrylate (NOEMA) and 2-phenoxyethyl methacrylate (POEMA) with a poly[2-(dimethylamino)ethyl methacrylate] macro-chain transfer agent (CTA) with an average degree of polymerization of 20 (PDMAEMA 20 ) is described. DMAEMA 20 -b-NOEMA y (y ¼ 20-125) block copolymers were readily prepared under dispersion conditions in ethanol at 708C. However, the polymerization of NOEMA was not well controlled, with size exclusion chromatograms being distinctly bi or multimodal with measured dispersities ( M ¼ M w = M n ) # 1.69. Though NOEMA copolymerization was not ideal, the resulting series of block copolymers did exhibit the anticipated full spectrum of nanoparticle morphologies (spheres, worms, and vesicles). Interestingly, these morphology transitions occurred over a relatively narrow range of block copolymer compositions. In the case of POEMA, copolymerization was also poorly controlled with 1.50 # M # 1.83 for the series of DMAEMA 20 -b-POEMA y copolymers. In contrast to the NOEMAbased copolymers, the POEMA series only yielded nanoparticles with a spherical morphology whose size increased with increasing average degrees of polymerization of the POEMA block. Collectively, though both NOEMA and POEMA can be utilized in ethanolic RAFT dispersion polymerization formulations, these preliminary studies suggest that neither appears to be an ideal aryl methacrylate choice as comonomer, especially if the goal is to combine the synthesis of welldefined copolymers with efficient nanoparticle formation.

show abstract

RAFT polymerization of hydroxy-functional methacrylic monomers under heterogeneous conditions: effect of varying the core-forming block

Abstract: Do isomeric core-forming blocks afford the same thermo-responsive behavior for diblock copolymer worm gels?

Cited by 58 publications

References 83 publications

The direct synthesis of interface-decorated reactive block copolymer nanoparticles via polymerisation-induced self-assembly

The direct synthesis of interface-decorated reactive block copolymer nanoparticles via polymerisation-induced self-assembly

Stimulus‐Responsive Nanoparticles and Associated (Reversible) Polymorphism via Polymerization Induced Self‐assembly (PISA)

Ethanolic RAFT Dispersion Polymerization of 2-(Naphthalen-2-yloxy)ethyl Methacrylate and 2-Phenoxyethyl Methacrylate with Poly[2-(dimethylamino)ethyl Methacrylate] Macro-Chain Transfer Agents

Contact Info

Product

Resources

About