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György C, Armes SP. Recent Advances in Polymerization-Induced Self-Assembly (PISA) Syntheses in Non-Polar Media. Angew Chem Int Ed Engl 2023; 62:e202308372. [PMID: 37409380 PMCID: PMC10952376 DOI: 10.1002/anie.202308372] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/05/2023] [Accepted: 07/05/2023] [Indexed: 07/07/2023]
Abstract
It 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.
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Affiliation(s)
- Csilla György
- Department of ChemistryUniversity of SheffieldDainton BuildingSheffieldSouth YorkshireS3 7HFUK
| | - Steven P. Armes
- Department of ChemistryUniversity of SheffieldDainton BuildingSheffieldSouth YorkshireS3 7HFUK
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Stiti A, Cenacchi Pereira AM, Lecommandoux S, Taton D. Group-Transfer Polymerization-Induced Self-Assembly (GTPISA) in Non-polar Media: An Organocatalyzed Route to Block Copolymer Nanoparticles at Room Temperature. Angew Chem Int Ed Engl 2023; 62:e202305945. [PMID: 37403785 DOI: 10.1002/anie.202305945] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/21/2023] [Accepted: 07/03/2023] [Indexed: 07/06/2023]
Abstract
Polymerization-induced self-assembly (PISA) enables the synthesis at large scale of a wide variety of functional nanoparticles. However, a large number of works are related to controlled radical polymerization (CRP) methods and are generally undertaken at elevated temperatures (>50 °C). Here is the first report on methacrylate-based nanoparticles fabricated by group transfer polymerization-induced self-assembly (GTPISA) in non-polar media (n-heptane). This GTPISA process is achieved at room temperature (RT) using 1-methoxy-1-(trimethylsiloxy)-2-methylprop-1-ene (MTS) and tetrabutylammonium bis-benzoate (TBABB) as initiator and organic catalyst, respectively. Under these conditions, well-defined metal-free and colorless diblock copolymers are produced with efficient crossover from the non-polar stabilizing poly(lauryl methacrylate) (PLMA) block to the non-soluble poly(benzyl methacrylate) (PBzMA) segment. The resulting PLMA-b-PBzMA block copolymers simultaneously self-assemble into nanostructures of various sizes and morphologies. GTPISA in non-polar solvent proceeds rapidly at RT and avoids the use of sulfur or halogenated compounds or metallic catalysts associated with the implementation of CRP methods, thus expanding the potential of PISA formulations for applications in non-polar environments.
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Affiliation(s)
- Assia Stiti
- Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux, INP-ENSCBP, 16 av. Pey Berland, 33607, Pessac cedex, France
- Centre de Recherche de Solaize, T, otalEnergies OneTech, Chemin du Canal-BP 22, 69360, Solaize, France
| | | | - Sébastien Lecommandoux
- Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux, INP-ENSCBP, 16 av. Pey Berland, 33607, Pessac cedex, France
| | - Daniel Taton
- Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux, INP-ENSCBP, 16 av. Pey Berland, 33607, Pessac cedex, France
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Debrie C, Coudert N, Guigner JM, Nicolai T, Stoffelbach F, Colombani O, Rieger J. Unimer Exchange Is not Necessary for Morphological Transitions in Polymerization-Induced Self-Assembly. Angew Chem Int Ed Engl 2023; 62:e202215134. [PMID: 36541924 PMCID: PMC10107197 DOI: 10.1002/anie.202215134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Polymerization-induced self-assembly (PISA) has established itself as a powerful and straightforward method to produce polymeric nano-objects of various morphologies in (aqueous) solution. Generally, spheres are formed in the early stages of polymerization that may evolve to higher order morphologies (worms or vesicles), as the solvophobic block grows during polymerization. Hitherto, the mechanisms involved in these morphological transitions during PISA are still not well understood. Combining a systematic study of a representative PISA system with rheological measurements, we demonstrate that-unexpectedly-unimer exchange is not necessary to form higher order morphologies during radical RAFT-mediated PISA. Instead, in the investigated aqueous PISA, the monomer present in the polymerization medium is responsible for the morphological transitions, even though it slows down unimer exchange.
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Affiliation(s)
- Clément Debrie
- Sorbonne Université & CNRS (UMR 8232), Institut Parisien de Chimie Moléculaire (IPCM), Polymer Chemistry Team, 4 Place Jussieu, 75252, Paris Cedex 05, France
| | - Noémie Coudert
- Le Mans Université & CNRS (UMR 6283), Institut des Molécules et Matériaux du Mans (IMMM), Avenue Olivier Messiaen, 72085, Le Mans Cedex 9, France
| | - Jean-Michel Guigner
- Sorbonne Université &CNRS, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), UMR 7590-IRD-MNHN, 75252, Paris Cedex 05, France
| | - Taco Nicolai
- Le Mans Université & CNRS (UMR 6283), Institut des Molécules et Matériaux du Mans (IMMM), Avenue Olivier Messiaen, 72085, Le Mans Cedex 9, France
| | - François Stoffelbach
- Sorbonne Université & CNRS (UMR 8232), Institut Parisien de Chimie Moléculaire (IPCM), Polymer Chemistry Team, 4 Place Jussieu, 75252, Paris Cedex 05, France
| | - Olivier Colombani
- Le Mans Université & CNRS (UMR 6283), Institut des Molécules et Matériaux du Mans (IMMM), Avenue Olivier Messiaen, 72085, Le Mans Cedex 9, France
| | - Jutta Rieger
- Sorbonne Université & CNRS (UMR 8232), Institut Parisien de Chimie Moléculaire (IPCM), Polymer Chemistry Team, 4 Place Jussieu, 75252, Paris Cedex 05, France
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György C, Neal TJ, Smith T, Growney DJ, Armes SP. Tuning the Glass Transition Temperature of a Core-Forming Block during Polymerization-Induced Self-Assembly: Statistical Copolymerization of Lauryl Methacrylate with Methyl Methacrylate Provides Access to Spheres, Worms, and Vesicles. Macromolecules 2022; 55:4091-4101. [PMID: 35634036 PMCID: PMC9134497 DOI: 10.1021/acs.macromol.2c00475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/22/2022] [Indexed: 12/31/2022]
Affiliation(s)
- Csilla György
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Thomas J. Neal
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Timothy Smith
- Lubrizol Ltd., Nether Lane, Hazelwood, Derbyshire DE56 4AN, U.K
| | | | - Steven P. Armes
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
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György C, Smith T, Growney DJ, Armes SP. Synthesis and derivatization of epoxy-functional sterically-stabilized diblock copolymer spheres in non-polar media: does the spatial location of the epoxy groups matter? Polym Chem 2022. [DOI: 10.1039/d2py00559j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Epoxy-functional sterically-stabilized diblock copolymer nanoparticles are prepared via PISA in mineral oil and then derivatized using various reagents and reaction conditions.
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Affiliation(s)
- Csilla György
- Dainton Building, Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK
| | - Timothy Smith
- Lubrizol Ltd, Nether Lane, Hazelwood, Derbyshire, DE56 4AN, UK
| | | | - Steven P. Armes
- Dainton Building, Department of Chemistry, The University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK
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György C, Verity C, Neal TJ, Rymaruk MJ, Cornel EJ, Smith T, Growney DJ, Armes SP. RAFT Dispersion Polymerization of Methyl Methacrylate in Mineral Oil: High Glass Transition Temperature of the Core-Forming Block Constrains the Evolution of Copolymer Morphology. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01528] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Csilla György
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Chloe Verity
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Thomas J. Neal
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Matthew J. Rymaruk
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Erik J. Cornel
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
| | - Timothy Smith
- Lubrizol Ltd., Nether Lane, Hazelwood, Derbyshire DE56 4AN, U.K
| | | | - Steven P. Armes
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K
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Affiliation(s)
- Ping Wei
- Department of Orthopedics, Shanghai Tenth People’s Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
- Department of Polymeric Materials, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China
| | - Erik Jan Cornel
- Department of Orthopedics, Shanghai Tenth People’s Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Jianzhong Du
- Department of Orthopedics, Shanghai Tenth People’s Hospital, Tongji University, 301 Middle Yanchang Road, Shanghai 200072, China
- Department of Polymeric Materials, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China
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Rymaruk MJ, O'Brien CT, György C, Darmau B, Jennings J, Mykhaylyk OO, Armes SP. Small-Angle X-Ray Scattering Studies of Block Copolymer Nano-Objects: Formation of Ordered Phases in Concentrated Solution During Polymerization-Induced Self-Assembly. Angew Chem Int Ed Engl 2021; 60:12955-12963. [PMID: 33725372 PMCID: PMC8252599 DOI: 10.1002/anie.202101851] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/12/2021] [Indexed: 01/13/2023]
Abstract
We report that polymerization-induced self-assembly (PISA) can be used to prepare lyotropic phases comprising diblock copolymer nano-objects in non-polar media. RAFT dispersion polymerization of benzyl methacrylate (BzMA) at 90 °C using a trithiocarbonate-capped hydrogenated polybutadiene (PhBD) steric stabilizer block in n-dodecane produces either spheres or worms that exhibit long-range order at 40 % w/w solids. NMR studies enable calculation of instantaneous copolymer compositions for each phase during the BzMA polymerization. As the PBzMA chains grow longer when targeting PhBD80 -PBzMA40 , time-resolved small-angle X-ray scattering reveals intermediate body-centered cubic (BCC) and hexagonally close-packed (HCP) sphere phases prior to formation of a final hexagonal cylinder phase (HEX). The HEX phase is lost on serial dilution and the aligned cylinders eventually form disordered flexible worms. The HEX phase undergoes an order-disorder transition on heating to 150 °C and a pure HCP phase forms on cooling to 20 °C.
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Affiliation(s)
- Matthew J. Rymaruk
- Dainton BuildingDepartment of ChemistryThe University of SheffieldSheffieldS3 7HFUK
- Present address: SyngentaJealott's HillBracknellBerkshireRG42 6EYUK
| | - Cate T. O'Brien
- Dainton BuildingDepartment of ChemistryThe University of SheffieldSheffieldS3 7HFUK
| | - Csilla György
- Dainton BuildingDepartment of ChemistryThe University of SheffieldSheffieldS3 7HFUK
| | - Bastien Darmau
- Dainton BuildingDepartment of ChemistryThe University of SheffieldSheffieldS3 7HFUK
| | - James Jennings
- Dainton BuildingDepartment of ChemistryThe University of SheffieldSheffieldS3 7HFUK
| | | | - Steven P. Armes
- Dainton BuildingDepartment of ChemistryThe University of SheffieldSheffieldS3 7HFUK
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Rymaruk MJ, O'Brien CT, György C, Darmau B, Jennings J, Mykhaylyk OO, Armes SP. Small‐Angle X‐Ray Scattering Studies of Block Copolymer Nano‐Objects: Formation of Ordered Phases in Concentrated Solution During Polymerization‐Induced Self‐Assembly. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Matthew J. Rymaruk
- Dainton Building Department of Chemistry The University of Sheffield Sheffield S3 7HF UK
- Present address: Syngenta Jealott's Hill Bracknell Berkshire RG42 6EY UK
| | - Cate T. O'Brien
- Dainton Building Department of Chemistry The University of Sheffield Sheffield S3 7HF UK
| | - Csilla György
- Dainton Building Department of Chemistry The University of Sheffield Sheffield S3 7HF UK
| | - Bastien Darmau
- Dainton Building Department of Chemistry The University of Sheffield Sheffield S3 7HF UK
| | - James Jennings
- Dainton Building Department of Chemistry The University of Sheffield Sheffield S3 7HF UK
| | - Oleksandr O. Mykhaylyk
- Dainton Building Department of Chemistry The University of Sheffield Sheffield S3 7HF UK
| | - Steven P. Armes
- Dainton Building Department of Chemistry The University of Sheffield Sheffield S3 7HF UK
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Dorsman IR, Derry MJ, Cunningham VJ, Brown SL, Williams CN, Armes SP. Tuning the vesicle-to-worm transition for thermoresponsive block copolymer vesicles prepared via polymerisation-induced self-assembly. Polym Chem 2021. [DOI: 10.1039/d0py01713b] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Does statistical copolymerization of n-butyl methacrylate with benzyl methacrylate lower the critical temperature required for vesicle-to-worm and worm-to-sphere transitions for diblock copolymer nano-objects in mineral oil?
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Affiliation(s)
| | - Matthew J. Derry
- Department of Chemistry
- The University of Sheffield
- South Yorkshire
- UK
| | | | | | | | - Steven P. Armes
- Department of Chemistry
- The University of Sheffield
- South Yorkshire
- UK
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Smith GN, Grillo I, Hallett JE. Molecular exchange in spherical diblock copolymer colloids synthesised by polymerisation-induced self-assembly. J Colloid Interface Sci 2020; 579:243-249. [PMID: 32592989 DOI: 10.1016/j.jcis.2020.06.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 10/24/2022]
Abstract
HYPOTHESIS To study molecular exchange between colloids requires the preparation of suitably labelled species. Deuterium isotopic labelling has been used to prepare two chemically identical yet isotopically distinguishable poly(lauryl methacrylate)-poly(methyl methacrylate) (PLMA-PMMA) diblock copolymer colloids by polymerisation-induced self-assembly (PISA) directly in an alkane solvent. Molecular exchange should be detectable by performing small-angle neutron scattering (SANS) measurements on the dispersions. EXPERIMENTS SANS measurements were performed on fully hydrogenous PLMA39-PMMA57 and deuterated core PLMA39-P(MMA-d8)57 colloids. They were mixed in equal amounts and heated to determine if molecular exchange occurred. PISA syntheses are often thermally initiated, and diblock copolymers self-assemble at elevated temperature, making this an important parameter to study. Experimental data for the mixture were compared to predicted curves for exchanged and non-exchanged colloids. FINDINGS The scattering of a mixture of fully hydrogenous and deuterated core copolymers does not disappear upon molecular exchange, due to the remaining contrast between the stabiliser and the core and solvent even after the cores fully exchange. By simultaneously fitting the SANS data from dispersions before mixing and using these parameters to constrain fitting the SANS data of mixtures, the molecular exchange between diblock copolymer micelles upon heating is clearly observed.
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Affiliation(s)
- Gregory N Smith
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom; Niels Bohr Institute, University of Copenhagen, H. C. Ørsted Institute, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
| | - Isabelle Grillo
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - James E Hallett
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
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Sobotta FH, Kuchenbrod M, Hoeppener S, Brendel JC. One polymer composition, various morphologies: the decisive influence of conditions on the polymerization-induced self-assembly (PISA) of N-acryloyl thiomorpholine. NANOSCALE 2020; 12:20171-20176. [PMID: 33020784 DOI: 10.1039/d0nr05150k] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Polymerization-induced self-assembly (PISA) represents a powerful technique for the preparation of nanostructures comprising various morphologies. Herein, we demonstrate that the recently introduced monomer N-acryloylthiomorpholine (NAT) features a unique self-assembly behaviour during an aqueous PISA. The one-pot, aqueous RAFT dispersion polymerization starting from short poly(N-acryloylmorpholine) (PNAM) enables access to all common solution morphologies including spheres, worms, vesicles and lamellae, at very low molar masses (< 8 kDa). Moreover, all these structures can be obtained for the same polymer composition and size by the variation of the polymerization temperature and concentration of the monomer. This exceptional self-assembly behavior is associated with the combination of a high glass transition temperature, excellent water solubility of the monomer, and the early onset of aggregation during the polymerization, which stabilizes the morphology at different stages. This PISA system opens up new opportunities to reproducibly create versatile, functional nanostructures and enables an independent evaluation of morphology-property relationships, as it is exemplarily shown for the oxidative degradation of spherical and wormlike micelles, as well as vesicles.
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Affiliation(s)
- Fabian H Sobotta
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany. and Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - Maren Kuchenbrod
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany. and Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - Stephanie Hoeppener
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany. and Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
| | - Johannes C Brendel
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany. and Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
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Czajka A, Armes SP. In situ SAXS studies of a prototypical RAFT aqueous dispersion polymerization formulation: monitoring the evolution in copolymer morphology during polymerization-induced self-assembly. Chem Sci 2020; 11:11443-11454. [PMID: 34094387 PMCID: PMC8162469 DOI: 10.1039/d0sc03411h] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 09/11/2020] [Indexed: 12/28/2022] Open
Abstract
Small-angle X-ray scattering (SAXS) is used to characterize the in situ formation of diblock copolymer spheres, worms and vesicles during reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate at 70 °C using a poly(glycerol monomethacrylate) steric stabilizer. 1H NMR spectroscopy indicates more than 99% HPMA conversion within 80 min, while transmission electron microscopy and dynamic light scattering studies are consistent with the final morphology being pure vesicles. Analysis of time-resolved SAXS patterns for this prototypical polymerization-induced self-assembly (PISA) formulation enables the evolution in copolymer morphology, particle diameter, mean aggregation number, solvent volume fraction, surface density of copolymer chains and their mean inter-chain separation distance at the nanoparticle surface to be monitored. Furthermore, the change in vesicle diameter and membrane thickness during the final stages of polymerization supports an 'inward growth' mechanism.
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Affiliation(s)
- Adam Czajka
- Dainton Building Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - Steven P Armes
- Dainton Building Brook Hill Sheffield South Yorkshire S3 7HF UK
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Cornel EJ, O'Hora PS, Smith T, Growney DJ, Mykhaylyk OO, Armes SP. SAXS studies of the thermally-induced fusion of diblock copolymer spheres: formation of hybrid nanoparticles of intermediate size and shape. Chem Sci 2020; 11:4312-4321. [PMID: 34122889 PMCID: PMC8152590 DOI: 10.1039/d0sc00569j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/20/2020] [Indexed: 12/19/2022] Open
Abstract
Dilute dispersions of poly(lauryl methacrylate)-poly(benzyl methacrylate) (PLMA-PBzMA) diblock copolymer spheres (a.k.a. micelles) of differing mean particle diameter were mixed and thermally annealed at 150 °C to produce spherical nanoparticles of intermediate size. The two initial dispersions were prepared via reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate in n-dodecane at 90 °C. Systematic variation of the mean degree of polymerization of the core-forming PBzMA block enabled control over the mean particle diameter: small-angle X-ray scattering (SAXS) analysis indicated that PLMA39-PBzMA97 and PLMA39-PBzMA294 formed well-defined, non-interacting spheres at 25 °C with core diameters of 21 ± 2 nm and 48 ± 5 nm, respectively. When heated separately, both types of nanoparticles regained their original dimensions during a 25-150-25 °C thermal cycle. However, the cores of the smaller nanoparticles became appreciably solvated when annealed at 150 °C, whereas the larger nanoparticles remained virtually non-solvated at this temperature. Moreover, heating caused a significant reduction in mean aggregation number for the PLMA39-PBzMA97 nanoparticles, suggesting their partial dissociation at 150 °C. Binary mixtures of PLMA39-PBzMA97 and PLMA39-PBzMA294 nanoparticles were then studied over a wide range of compositions. For example, annealing a 1.0% w/w equivolume binary mixture led to the formation of a single population of spheres of intermediate mean diameter (36 ± 4 nm). Thus we hypothesize that the individual PLMA39-PBzMA97 chains interact with the larger PLMA39-PBzMA294 nanoparticles to form the hybrid nanoparticles. Time-resolved SAXS studies confirm that the evolution in copolymer morphology occurs on relatively short time scales (within 20 min at 150 °C) and involves weakly anisotropic intermediate species. Moreover, weakly anisotropic nanoparticles can be obtained as a final copolymer morphology over a restricted range of compositions (e.g. for PLMA39-PBzMA97 volume fractions of 0.20-0.35) when heating dilute dispersions of such binary nanoparticle mixtures up to 150 °C. A mechanism involving both chain expulsion/insertion and micelle fusion/fission is proposed to account for these unexpected observations.
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Affiliation(s)
- E J Cornel
- Department of Chemistry, University of Sheffield Dainton Building, Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - P S O'Hora
- Lubrizol Ltd Nether Lane, Hazelwood Derbyshire DE56 4AN UK
| | - T Smith
- Lubrizol Ltd Nether Lane, Hazelwood Derbyshire DE56 4AN UK
| | - D J Growney
- Lubrizol Ltd Nether Lane, Hazelwood Derbyshire DE56 4AN UK
| | - O O Mykhaylyk
- Department of Chemistry, University of Sheffield Dainton Building, Brook Hill Sheffield South Yorkshire S3 7HF UK
| | - S P Armes
- Department of Chemistry, University of Sheffield Dainton Building, Brook Hill Sheffield South Yorkshire S3 7HF UK
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