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McBride RJ, Geneste E, Xie A, Ryan AJ, Miller JF, Blanazs A, Rösch C, Armes SP. Low-Viscosity Route to High-Molecular-Weight Water-Soluble Polymers: Exploiting the Salt Sensitivity of Poly( N-acryloylmorpholine). Macromolecules 2024; 57:2432-2445. [PMID: 38495382 PMCID: PMC10938879 DOI: 10.1021/acs.macromol.3c02616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/26/2024] [Accepted: 02/07/2024] [Indexed: 03/19/2024]
Abstract
We report a new one-pot low-viscosity synthetic route to high molecular weight non-ionic water-soluble polymers based on polymerization-induced self-assembly (PISA). The RAFT aqueous dispersion polymerization of N-acryloylmorpholine (NAM) is conducted at 30 °C using a suitable redox initiator and a poly(2-hydroxyethyl acrylamide) (PHEAC) precursor in the presence of 0.60 M ammonium sulfate. This relatively low level of added electrolyte is sufficient to salt out the PNAM block, while steric stabilization is conferred by the relatively short salt-tolerant PHEAC block. A mean degree of polymerization (DP) of up to 6000 was targeted for the PNAM block, and high NAM conversions (>96%) were obtained in all cases. On dilution with deionized water, the as-synthesized sterically stabilized particles undergo dissociation to afford molecularly dissolved chains, as judged by dynamic light scattering and 1H NMR spectroscopy studies. DMF GPC analysis confirmed a high chain extension efficiency for the PHEAC precursor, but relatively broad molecular weight distributions were observed for the PHEAC-PNAM diblock copolymer chains (Mw/Mn > 1.9). This has been observed for many other PISA formulations when targeting high core-forming block DPs and is tentatively attributed to chain transfer to polymer, which is well known for polyacrylamide-based polymers. In fact, relatively high dispersities are actually desirable if such copolymers are to be used as viscosity modifiers because solution viscosity correlates closely with Mw. Static light scattering studies were also conducted, with a Zimm plot indicating an absolute Mw of approximately 2.5 × 106 g mol-1 when targeting a PNAM DP of 6000. Finally, it is emphasized that targeting such high DPs leads to a sulfur content for this latter formulation of just 23 ppm, which minimizes the cost, color, and malodor associated with the organosulfur RAFT agent.
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Affiliation(s)
- Rory J. McBride
- Chemistry
Department, University of Sheffield, Brook Hill, Sheffield S3 7HF, South
Yorkshire, U.K.
| | - Elisa Geneste
- Chemistry
Department, University of Sheffield, Brook Hill, Sheffield S3 7HF, South
Yorkshire, U.K.
| | - Andi Xie
- Chemistry
Department, University of Sheffield, Brook Hill, Sheffield S3 7HF, South
Yorkshire, U.K.
| | - Anthony J. Ryan
- Chemistry
Department, University of Sheffield, Brook Hill, Sheffield S3 7HF, South
Yorkshire, U.K.
| | - John F. Miller
- Enlighten
Scientific LLC, Hillsborough, North Carolina 27278, United States
| | - Adam Blanazs
- BASF
SE, Carl-Bosch-Strasse
38, 67056 Ludwigshafen
am Rhein, Germany
| | - Christine Rösch
- BASF
SE, Carl-Bosch-Strasse
38, 67056 Ludwigshafen
am Rhein, Germany
| | - Steven P. Armes
- Chemistry
Department, University of Sheffield, Brook Hill, Sheffield S3 7HF, South
Yorkshire, U.K.
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Lukáš Petrova S, Sincari V, Konefał R, Pavlova E, Hrubý M, Pokorný V, Jäger E. Microwave Irradiation-Assisted Reversible Addition-Fragmentation Chain Transfer Polymerization-Induced Self-Assembly of pH-Responsive Diblock Copolymer Nanoparticles. ACS OMEGA 2022; 7:42711-42722. [PMID: 36467927 PMCID: PMC9713868 DOI: 10.1021/acsomega.2c04036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
Herein, we present a versatile platform for the synthesis of pH-responsive poly([N-(2-hydroxypropyl)]methacrylamide)-b-poly[2-(diisopropylamino)ethyl methacrylate] diblock copolymer (PHPMA-b-PDPA) nanoparticles (NPs) obtained via microwave-assisted reversible addition-fragmentation chain transfer polymerization-induced self-assembly (MWI-PISA). The N-(2-hydroxypropyl) methacrylamide (HPMA) monomer was first polymerized to obtain a macrochain transfer agent with polymerization degrees (DPs) of 23 and 51. Subsequently, using mCTA and 2-(diisopropylamino)ethyl methacrylate (DPA) as monomers, we successfully conducted MWI-PISA emulsion polymerization in aqueous solution with a solid content of 10 wt %. The NPs were obtained with high monomer conversion and polymerization rates. The resulting diblock copolymer NPs were analyzed by dynamic light scattering (DLS) and cryogenic-transmission electron microscopy (cryo-TEM). cryo-TEM studies reveal the presence of only NPs with spherical morphology such as micelles and polymer vesicles known as polymersomes. Under the selected conditions, we were able to fine-tune the morphology from micelles to polymersomes, which may attract considerable attention in the drug-delivery field. The capability for drug encapsulation using the obtained in situ pH-responsive NPs, the polymersomes based on PHPMA23-b-PDPA100, and the micelles based on PHPMA51-b-PDPA100 was demonstrated using the hydrophobic agent and fluorescent dye as Nile red (NR). In addition, the NP disassembly in slightly acidic environments enables fast NR release.
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Wan J, Fan B, Thang SH. RAFT-mediated polymerization-induced self-assembly (RAFT-PISA): current status and future directions. Chem Sci 2022; 13:4192-4224. [PMID: 35509470 PMCID: PMC9006902 DOI: 10.1039/d2sc00762b] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/17/2022] [Indexed: 12/13/2022] Open
Abstract
Polymerization-induced self-assembly (PISA) combines polymerization and self-assembly in a single step with distinct efficiency that has set it apart from the conventional solution self-assembly processes. PISA holds great promise for large-scale production, not only because of its efficient process for producing nano/micro-particles with high solid content, but also thanks to the facile control over the particle size and morphology. Since its invention, many research groups around the world have developed new and creative approaches to broaden the scope of PISA initiations, morphologies and applications, etc. The growing interest in PISA is certainly reflected in the increasing number of publications over the past few years, and in this review, we aim to summarize these recent advances in the emerging aspects of RAFT-mediated PISA. These include (1) non-thermal initiation processes, such as photo-, enzyme-, redox- and ultrasound-initiation; the achievements of (2) high-order structures, (3) hybrid materials and (4) stimuli-responsive nano-objects by design and adopting new monomers and new processes; (5) the efforts in the realization of upscale production by utilization of high throughput technologies, and finally the (6) applications of current PISA nano-objects in different fields and (7) its future directions.
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Affiliation(s)
- Jing Wan
- School of Chemistry, Monash University Clayton VIC 3800 Australia
| | - Bo Fan
- School of Chemistry, Monash University Clayton VIC 3800 Australia
| | - San H Thang
- School of Chemistry, Monash University Clayton VIC 3800 Australia
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