1
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Hanson MG, Grimme CJ, Kreofsky NW, Panda S, Reineke TM. Blended Block Polycation Micelles Enhance Antisense Oligonucleotide Delivery. Bioconjug Chem 2023; 34:1418-1428. [PMID: 37437196 DOI: 10.1021/acs.bioconjchem.3c00186] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Nucleic acid-based medicines and vaccines are becoming an important part of our therapeutic toolbox. One key genetic medicine is antisense oligonucleotides (ASOs), which are short single-stranded nucleic acids that downregulate protein production by binding to mRNA. However, ASOs cannot enter the cell without a delivery vehicle. Diblock polymers containing cationic and hydrophobic blocks self-assemble into micelles that have shown improved delivery compared to linear nonmicelle variants. Yet synthetic and characterization bottlenecks have hindered rapid screening and optimization. In this study, we aim to develop a method to increase throughput and discovery of new micelle systems by mixing diblock polymers together to rapidly form new micelle formulations. We synthesized diblocks containing an n-butyl acrylate block chain extended with cationic moieties amino ethyl acrylamide (A), dimethyl amino ethyl acrylamide (D), or morpholino ethyl acrylamide (M). These diblocks were then self-assembled into homomicelles (A100, D100, and M100)), mixed micelles comprising 2 homomicelles (MixR%+R'%), and blended diblock micelles comprising 2 diblocks blended into one micelle (BldR%R'%) and tested for ASO delivery. Interestingly, we observed that mixing or blending M with A (BldA50M50 and MixA50+M50) did not improve transfection efficiency compared to A100; however, when M was mixed with D, there was a significant increase in transfection efficacy for the mixed micelle MixD50+M50 compared to D100. We further examined mixed and blended D systems at different ratios. We observed a large increase in transfection and minimal change in toxicity when M was mixed with D at a low percentage of D incorporation in mixed diblock micelles (i.e., BldD20M80) compared to D100 and MixD20+M80. To understand the cellular mechanisms that may result in these differences, we added proton pump inhibitor Bafilomycin-A1 (Baf-A1) to the transfection experiments. Formulations that contain D decreased in performance in the presence of Baf-A1, indicating that micelles with D rely on the proton sponge effect for endosomal escape more than micelles with A. This result supports our conclusion that M is able to modulate transfection of D, but not with A. This research shows that polymer blending in a manner similar to that of lipids can significantly boost transfection efficiency and is a facile way to increase throughput of testing, optimization, and successful formulation identification for polymeric nucleic acid delivery systems.
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Affiliation(s)
- Mckenna G Hanson
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Christian J Grimme
- Department of Chemical Engineering & Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Nicholas W Kreofsky
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Sidharth Panda
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Theresa M Reineke
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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2
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Guo C, Yuan H, Yu Y, Gao Z, Zhang Y, Yin T, He H, Gou J, Tang X. FRET-based analysis on the structural stability of polymeric micelles: Another key attribute beyond PEG coverage and particle size affecting the blood clearance. J Control Release 2023; 360:734-746. [PMID: 37454913 DOI: 10.1016/j.jconrel.2023.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Various attributes of micelles, such as PEG density and particle size, are considered to be related to blood clearance. The structural stability of micelles is another key attribute that will affect the in vivo fate. This study employed fluorescence resonance energy transfer (FRET) analysis to guide the preparation of polymeric micelles with different structural stability. Micelles prepared using copolymers with longer hydrophobic blocks showed higher structural stability; emulsification was a better method than nanoprecipitation to prepare stable micelles. The fast chain exchange kinetics and the high-water content of micellar cores explained the low structural stability of those micelles. Moreover, this study highlighted the importance of structural stability that affected blood clearance in concert with PEG length and particle size. One-third of the small and stable micelles were detected in the blood 24 h after injection. While unstable micelles would be cleared from the circulation within 4 h. Notably, there would be a threshold of structural stability. Micelles with structural stability below this threshold were quickly cleared even if they possessed a longer PEG length and a smaller size. In contrast, higher structural stability allowed polymeric micelles to maintain higher integrity in vivo and enhance tumor accumulation and anti-tumor efficacy. In conclusion, this study systematically analyzed the importance of the structural stability of micelles on the in vivo fate.
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Affiliation(s)
- Chen Guo
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China
| | - Haoyang Yuan
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China
| | - Ying Yu
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China
| | - Zhencheng Gao
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China
| | - Yu Zhang
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China
| | - Tian Yin
- School of Functional Food and Wine, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China
| | - Haibing He
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China
| | - Jingxin Gou
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China.
| | - Xing Tang
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, Liaoning, PR China.
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3
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Gupta S, Lodge TP. Effect of Changing Interfacial Tension on Fragmentation Kinetics of Block Copolymer Micelles. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- Supriya Gupta
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Timothy P. Lodge
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
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4
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Lodge TP, Seitzinger CL, Seeger SC, Yang S, Gupta S, Dorfman KD. Dynamics and Equilibration Mechanisms in Block Copolymer Particles. ACS POLYMERS AU 2022; 2:397-416. [PMID: 36536887 PMCID: PMC9756915 DOI: 10.1021/acspolymersau.2c00033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 08/10/2022] [Accepted: 08/10/2022] [Indexed: 06/17/2023]
Abstract
Self-assembly of block copolymers into interesting and useful nanostructures, in both solution and bulk, is a vibrant research arena. While much attention has been paid to characterization and prediction of equilibrium phases, the associated dynamic processes are far from fully understood. Here, we explore what is known and not known about the equilibration of particle phases in the bulk, and spherical micelles in solution. The presumed primary equilibration mechanisms are chain exchange, fusion, and fragmentation. These processes have been extensively studied in surfactants and lipids, where they occur on subsecond time scales. In contrast, increased chain lengths in block copolymers create much larger barriers, and time scales can become prohibitively slow. In practice, equilibration of block copolymers is achievable only in proximity to the critical micelle temperature (in solution) or the order-disorder transition (in the bulk). Detailed theories for these processes in block copolymers are few. In the bulk, the rate of chain exchange can be quantified by tracer diffusion measurements. Often the rate of equilibration, in terms of number density and aggregation number of particles, is much slower than chain exchange, and consequently observed particle phases are often metastable. This is particularly true in regions of the phase diagram where Frank-Kasper phases occur. Chain exchange in solution has been explored quantitatively by time-resolved SANS, but the results are not well captured by theory. Computer simulations, particularly via dissipative particle dynamics, are beginning to shed light on the chain escape mechanism at the molecular level. The rate of fragmentation has been quantified in a few experimental systems, and TEM images support a mechanism akin to the anaphase stage of mitosis in cells, via a thin neck that pinches off to produce two smaller micelles. Direct measurements of micelle fusion are quite rare. Suggestions for future theoretical, computational, and experimental efforts are offered.
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Affiliation(s)
- Timothy P. Lodge
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
- Department
of Chemical Engineering & Materials Science, University of Minnesota 451 Washington Ave SE, Minneapolis, Minnesota 55455, United States
| | - Claire L. Seitzinger
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Sarah C. Seeger
- Department
of Chemical Engineering & Materials Science, University of Minnesota 451 Washington Ave SE, Minneapolis, Minnesota 55455, United States
| | - Sanghee Yang
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Supriya Gupta
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Kevin D. Dorfman
- Department
of Chemical Engineering & Materials Science, University of Minnesota 451 Washington Ave SE, Minneapolis, Minnesota 55455, United States
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5
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Seeger SC, Lodge TP, Dorfman KD. Mechanism of Escape of a Single Chain from a Diblock Copolymer Micelle. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sarah C. Seeger
- Department of Chemical Engineering and Materials Science, University of Minnesota─Twin Cities, Minneapolis, Minnesota55455, United States
| | - Timothy P. Lodge
- Department of Chemical Engineering and Materials Science, University of Minnesota─Twin Cities, Minneapolis, Minnesota55455, United States
- Department of Chemistry, University of Minnesota─Twin Cities, Minneapolis, Minnesota55455, United States
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota─Twin Cities, Minneapolis, Minnesota55455, United States
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6
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Williams ER, van den Bergh W, Stefik M. High- χ, low- N micelles from partially perfluorinated block polymers. SOFT MATTER 2022; 18:7917-7930. [PMID: 36017726 DOI: 10.1039/d2sm00513a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Kinetically trapped ("persistent") micelles enable emerging applications requiring a constant core diameter. Preserving a χN barrier to chain exchange with low-N requires a commensurately higher χcore-solvent for micelle persistence. Low-N, high-χ micelles containing fluorophobic interactions were studied using poly(ethylene oxide-b-perfluorooctyl acrylate)s (O45FX, x = 8, 11) in methanolic solutions. DLS analysis of micelles revealed chain exchange only for O45F8 while SAXS analysis suggested elongated core block conformations commensurate with the contour lengths. Micelle chain exchange from solution perturbations were examined by characterizing their behavior as templates for inorganic materials via SAXS and SEM. In contrast to the F8 analog, the larger χN barrier for the O45F11 enabled persistent micelle behavior in both thin films and bulk samples despite the low Tg micelle core. Careful measures of micelle core diameters and pore sizes revealed that the nanoparticle distribution extended through the corona and 0.52 ± 0.15 nm into the core-corona interface, highlighting thermodynamics favoring both locations simultaneously.
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Affiliation(s)
- Eric R Williams
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
| | - Wessel van den Bergh
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
| | - Morgan Stefik
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
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7
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Han XG, Sun ZH, Liang N, Zhang H. Aggregate behavior in amphiphilic coil/rod block copolymer solutions. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2022.111663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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8
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Seitzinger CL, Hall CC, Lodge TP. Photoreversible Order–Disorder Transitions in Block Copolymer/Ionic Liquid Solutions. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Claire L. Seitzinger
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Cecilia C. Hall
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Timothy P. Lodge
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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9
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Ge S, Samanta S, Li B, Carden GP, Cao PF, Sokolov AP. Unravelling the Mechanism of Viscoelasticity in Polymers with Phase-Separated Dynamic Bonds. ACS NANO 2022; 16:4746-4755. [PMID: 35234439 DOI: 10.1021/acsnano.2c00046] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Incorporation of dynamic (reversible) bonds within polymer structure enables properties such as self-healing, shape transformation, and recyclability. These dynamic bonds, sometimes refer as stickers, can form clusters by phase-segregation from the polymer matrix. These systems can exhibit interesting viscoelastic properties with an unusually high and extremely long rubbery plateau. Understanding how viscoelastic properties of these materials are controlled by the hierarchical structure is crucial for engineering of recyclable materials for various future applications. Here we studied such systems made from short telechelic polydimethylsiloxane chains by employing a broad range of experimental techniques. We demonstrate that formation of a percolated network of interfacial layers surrounding clusters enhances mechanical modulus in these phase-separated systems, whereas single chain hopping between the clusters results in macroscopic flow. On the basis of the results, we formulated a general scenario describing viscoelastic properties of phase-separated dynamic polymers, which will foster development of recyclable materials with tunable rheological properties.
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Affiliation(s)
- Sirui Ge
- Department of Material Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Subarna Samanta
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bingrui Li
- The Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - G Peyton Carden
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Peng-Fei Cao
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Alexei P Sokolov
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
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10
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Seeger SC, Dorfman KD, Lodge TP. Free Energy Trajectory for Escape of a Single Chain from a Diblock Copolymer Micelle. ACS Macro Lett 2021; 10:1570-1575. [PMID: 35549128 DOI: 10.1021/acsmacrolett.1c00508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We use umbrella sampling to compute the free energy trajectory of a single chain undergoing expulsion from an isolated diblock copolymer micelle. This approach elucidates the experimentally unobservable transition state, identifies the spatial position of the maximum free energy, and reveals the chain conformation of a single chain as it undergoes expulsion. Combining umbrella sampling with dissipative particle dynamics simulations of A4B8 micelles reveals that the core block (A) of the expelled chain remains partially stretched at the transition state, in contrast with the collapsed state assumed in some previous models. The free energy barrier increases linearly with the Flory-Huggins interaction parameter χ up to large interaction energies, where the structure of the otherwise spherical core apparently deforms near the transition state.
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Affiliation(s)
- Sarah C. Seeger
- Department of Chemical Engineering and Materials Science, University of Minnesota − Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota − Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Timothy P. Lodge
- Department of Chemical Engineering and Materials Science, University of Minnesota − Twin Cities, Minneapolis, Minnesota 55455, United States
- Department of Chemistry, University of Minnesota − Twin Cities, Minneapolis, Minnesota 55455, United States
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11
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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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12
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Heo TY, Kim S, Chen L, Sokolova A, Lee S, Choi SH. Molecular Exchange Kinetics in Complex Coacervate Core Micelles: Role of Associative Interaction. ACS Macro Lett 2021; 10:1138-1144. [PMID: 35549078 DOI: 10.1021/acsmacrolett.1c00482] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular exchange dynamics between spherical complex coacervate core micelles (C3Ms) are documented using time-resolved small-angle neutron scattering measurements (TR-SANS), and the effects of salt concentration, type of charges, and core block polydispersity to the chain exchange are quantified. Isotopically labeled block copolyelectrolytes were prepared by postpolymerization modification of two nearly identical poly(ethylene oxide-b-allyl glycidyl ether), one with normal and the other with deuterated PEO blocks (i.e., hPEO-PAGE and dPEO-PAGE). The observed rates at multiple salt concentrations are consolidated using time-salt superposition shift factors representing chain exchange rates and analyzed. Our comprehensive analytical relaxation function based on the sticky-Rouse model and the thermodynamic barrier for core block extraction successfully describes the molecular exchange kinetics between the isotopically labeled C3Ms. We believe this work provides fundamental design criteria for C3Ms with engineered chain exchange dynamics.
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Affiliation(s)
- Tae-Young Heo
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Sojeong Kim
- School of Chemical and Biological Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Liwen Chen
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Anna Sokolova
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
| | - Sangwoo Lee
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Soo-Hyung Choi
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea
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13
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Karayianni M, Pispas S. Block copolymer solution self‐assembly: Recent advances, emerging trends, and applications. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210430] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Maria Karayianni
- Theoretical and Physical Chemistry Institute National Hellenic Research Foundation Athens Greece
| | - Stergios Pispas
- Theoretical and Physical Chemistry Institute National Hellenic Research Foundation Athens Greece
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14
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Early JT, Block A, Yager KG, Lodge TP. Molecular Weight Dependence of Block Copolymer Micelle Fragmentation Kinetics. J Am Chem Soc 2021; 143:7748-7758. [PMID: 33988984 DOI: 10.1021/jacs.1c02147] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effect of molecular weight (M) on the fragmentation kinetics of micelles formed by 1,2-polybutadiene-block-poly(ethylene oxide) (PB-PEO) copolymers was studied in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. A series of six samples, with total M ranging from 104 to 105 g mol-1 and nearly constant composition (fPEO ≈ 0.4), were examined; all six formed spherical micelles with PEO coronas. Nonequilibrium PB-PEO micelles were prepared by direct dissolution, a process that systematically produces nanoparticles with mean aggregation numbers more than twice the equilibrium values. When subjected to high temperature annealing (170 °C), the average micelle radius was found to decrease substantially, as determined by temperature-jump dynamic light scattering (T-jump DLS) and time-resolved small-angle X-ray scattering (TR-SAXS). The characteristic fragmentation times (τ) were found to increase strongly with increasing degree of polymerization N, as τ ∼ N1.8. This result compares favorably with the prediction of a previously untested model.
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Affiliation(s)
| | | | - Kevin G Yager
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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15
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Kim S, Lee S, Choi SH, Char K. Chain Exchange Kinetics of Bottlebrush Block Copolymer Micelles. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00155] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Seyoung Kim
- Department of Chemical and Biological Engineering, Seoul National University, Seoul 08826, Republic of Korea
- Department of Chemical Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Sangho Lee
- Department of Chemical Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Soo-Hyung Choi
- Department of Chemical Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Kookheon Char
- Department of Chemical and Biological Engineering, Seoul National University, Seoul 08826, Republic of Korea
- The National Creative Research Initiative Center for Intelligent Hybrids, Seoul National University, Seoul 08826, Republic of Korea
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16
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17
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Landazuri G, Fernandez V, Soltero J, Rharbi Y. Length of the Core Forming Block Effect on Fusion and Fission Dynamics at Equilibrium in PEO–PPO–PEO Triblock Copolymer Micelles in the Spherical Regime. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c01520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- G. Landazuri
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
- Departamento de Ingeniería Química, CUCEI, Universidad de Guadalajara, Blvd. M. García Barragán # 1421, Guadalajara, Jalisco 44430, Mexico
| | - V.V.A. Fernandez
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
- Departamento de Ciencias Tecnológicas, Universidad de Guadalajara, Av. Universidad No. 1115, Ocotlán, Jalisco 47820, Mexico
| | - J.F.A. Soltero
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
- Departamento de Ingeniería Química, CUCEI, Universidad de Guadalajara, Blvd. M. García Barragán # 1421, Guadalajara, Jalisco 44430, Mexico
| | - Y. Rharbi
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
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18
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Huang GR, Tung CH, Chang D, Lam CN, Do C, Shinohara Y, Chang SY, Wang Y, Hong K, Chen WR. Determining population densities in bimodal micellar solutions using contrast-variation small angle neutron scattering. J Chem Phys 2020; 153:184902. [PMID: 33187411 DOI: 10.1063/5.0024410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Self-assembly of amphiphilic polymers in water is of fundamental and practical importance. Significant amounts of free unimers and associated micellar aggregates often coexist over a wide range of phase regions. The thermodynamic and kinetic properties of the microphase separation are closely related to the relative population density of unimers and micelles. Although the scattering technique has been employed to identify the structure of micellar aggregates as well as their time-evolution, the determination of the population ratio of micelles to unimers remains a challenging problem due to their difference in scattering power. Here, using small-angle neutron scattering (SANS), we present a comprehensive structural study of amphiphilic n-dodecyl-PNIPAm polymers, which shows a bimodal size distribution in water. By adjusting the deuterium/hydrogen ratio of water, the intra-micellar polymer and water distributions are obtained from the SANS spectra. The micellar size and number density are further determined, and the population densities of micelles and unimers are calculated to quantitatively address the degree of micellization at different temperatures. Our method can be used to provide an in-depth insight into the solution properties of microphase separation, which are present in many amphiphilic systems.
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Affiliation(s)
- Guan-Rong Huang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Chi-Huan Tung
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Dongsook Chang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Christopher N Lam
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Changwoo Do
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Yuya Shinohara
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Shou-Yi Chang
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yangyang Wang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Kunlun Hong
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Wei-Ren Chen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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19
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Kim S, Cho Y, Kim JH, Song S, Lim J, Choi SH, Char K. Structural Analysis of Bottlebrush Block Copolymer Micelles Using Small-Angle X-ray Scattering. ACS Macro Lett 2020; 9:1261-1266. [PMID: 35638628 DOI: 10.1021/acsmacrolett.0c00442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We present structural analysis of spherical diblock copolymer micelles where core blocks have bottlebrush architecture. The dependence of the core radius (Rcore) and the corona thickness (Lcorona) on the core block length (Ncore) is investigated using small-angle X-ray scattering (SAXS) and discussed in terms of the stiffness of a core-forming polymer posed by its long fluoroalkyl side chains. The conformation of the core block is strongly stretched, and the measured exponents α and β from power-law correlations, Rcore ∼ Ncoreα and Lcorona ∼ Ncoreβ, respectively, are greater than those from any scaling predictions for block copolymer micelles with a flexible, linear core-block. Such deviations are attributed to the appreciable chain stiffness of the bottlebrush core block, and a simple model is suggested to understand how the core block stiffness influences both the dimensions of core and corona.
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Affiliation(s)
- Seyoung Kim
- Department of Chemical and Biological Engineering, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Yunshik Cho
- Department of Chemical and Biological Engineering, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jee Hyun Kim
- Department of Chemical and Biological Engineering, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Sanghoon Song
- Department of Chemistry, Kyung Hee University, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Jeewoo Lim
- Department of Chemistry, Kyung Hee University, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Soo-Hyung Choi
- Department of Chemical Engineering, Hongik University, Mapo-gu, Seoul 04066, Republic of Korea
| | - Kookheon Char
- Department of Chemical and Biological Engineering, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea
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20
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21
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Self-assembled nanostructures from amphiphilic block copolymers prepared via ring-opening metathesis polymerization (ROMP). Prog Polym Sci 2020. [DOI: 10.1016/j.progpolymsci.2020.101278] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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22
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Early JT, Yager KG, Lodge TP. Direct Observation of Micelle Fragmentation via In Situ Liquid-Phase Transmission Electron Microscopy. ACS Macro Lett 2020; 9:756-761. [PMID: 35648564 DOI: 10.1021/acsmacrolett.0c00273] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recently, attention has been directed toward understanding the dynamics and relaxation kinetics of block copolymer micelles, including mechanisms such as micelle fragmentation and fusion. The few prior studies on block copolymer micelle fragmentation relied on ensemble averaging techniques such as small-angle X-ray scattering and dynamic light scattering; some individual particles were imaged by ex situ transmission electron microscopy. Here we report the direct observation of fragmentation for three molecular weights of 1,2-polybutadiene-block-poly(ethylene oxide) (PB-PEO) micelles in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide using high-temperature liquid-phase transmission electron microscopy (LP-TEM). The use of in situ LP-TEM provides unique insights into the evolution of block copolymer micelles during fragmentation. Specifically, upon heating to 170 °C, a sequence of morphological transitions from a spherical micelle to a prolate ellipsoid, then a "peanut" shape, followed by a two-spherical-compartment micelle was observed, where the last is presumed to be the transition state.
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Affiliation(s)
| | - Kevin G. Yager
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
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23
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Cornel EJ, Smith GN, Rogers SE, Hallett JE, Growney DJ, Smith T, O'Hora PS, van Meurs S, Mykhaylyk OO, Armes SP. Time-resolved small-angle neutron scattering studies of the thermally-induced exchange of copolymer chains between spherical diblock copolymer nanoparticles prepared via polymerization-induced self-assembly. SOFT MATTER 2020; 16:3657-3668. [PMID: 32227048 DOI: 10.1039/c9sm02425e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sterically-stabilized diblock copolymer nanoparticles (a.k.a. micelles) are prepared directly in non-polar media via polymerization-induced self-assembly (PISA). More specifically, a poly(lauryl methacrylate) chain transfer agent is chain-extended via reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of methyl methacrylate (MMA) to form sterically-stabilized spheres at 20% w/w solids in n-dodecane at 90 °C. Both fully hydrogenous (PLMA39-PMMA55 and PLMA39-PMMA94) and core-deuterated (PLMA39-d8PMMA57 and PLMA39-d8PMMA96) spherical nanoparticles with mean core diameters of approximately 20 nm were prepared using this protocol. After diluting each dispersion in turn to 1.0% w/w with n-dodecane, small-angle X-ray scattering studies confirmed essentially no change in spherical nanoparticle diameter after thermal annealing at 150 °C. Time-resolved small angle neutron scattering was used to examine whether copolymer chain exchange occurs between such nanoparticles at elevated temperatures. Copolymer chain exchange for a binary mixture of PLMA39-PMMA55 and PLMA39-d8PMMA57 nanoparticles produced hybrid (mixed) cores containing both PMMA55 and d8PMMA57 blocks within 3 min at 150 °C. In contrast, a binary mixture of PLMA39-PMMA94 and PLMA39-d8PMMA96 nanoparticles required 8 min at this temperature before no further reduction in neutron scattering intensity could be observed. These observations suggest that the rate of copolymer chain exchange depends on the degree of polymerization of the core-forming block. Relatively slow copolymer chain exchange was also observed at 80 °C, which is below the Tg of the core-forming PMMA block as determined by DSC studies. These observations confirm rapid exchange of individual copolymer chains between sterically-stabilized nanoparticles at elevated temperature. The implications of these findings are briefly discussed in the context of PISA, which is a powerful technique for the synthesis of sterically-stabilized nanoparticles.
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Affiliation(s)
- Erik J Cornel
- Department of Chemistry, University of Sheffield, Brook Hill, Dainton Building, Sheffield, South Yorkshire S3 7HF, UK.
| | - Gregory N Smith
- Department of Chemistry, University of Sheffield, Brook Hill, Dainton Building, Sheffield, South Yorkshire S3 7HF, UK. and Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Sarah E Rogers
- Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK
| | - James E Hallett
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
| | - David J Growney
- Lubrizol Ltd, Nether Lane, Hazelwood, Derbyshire DE56 4AN, UK
| | - Timothy Smith
- Lubrizol Ltd, Nether Lane, Hazelwood, Derbyshire DE56 4AN, UK
| | - Paul S O'Hora
- Lubrizol Ltd, Nether Lane, Hazelwood, Derbyshire DE56 4AN, UK
| | - Sandra van Meurs
- Department of Chemistry, University of Sheffield, Brook Hill, Dainton Building, Sheffield, South Yorkshire S3 7HF, UK.
| | - Oleksandr O Mykhaylyk
- Department of Chemistry, University of Sheffield, Brook Hill, Dainton Building, Sheffield, South Yorkshire S3 7HF, UK.
| | - Steven P Armes
- Department of Chemistry, University of Sheffield, Brook Hill, Dainton Building, Sheffield, South Yorkshire S3 7HF, UK.
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24
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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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25
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Prhashanna A, Dormidontova EE. Micelle Self-Assembly and Chain Exchange Kinetics of Tadpole Block Copolymers with a Cyclic Corona Block. Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ammu Prhashanna
- Polymer Program, Institute of Materials Science and Physics Department, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Elena E. Dormidontova
- Polymer Program, Institute of Materials Science and Physics Department, University of Connecticut, Storrs, Connecticut 06269, United States
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26
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Early JT, Lodge TP. Fragmentation of 1,2-Polybutadiene-block-Poly(ethylene oxide) Micelles in Imidazolium-Based Ionic Liquids. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Zhao D, Ma Y, Wang E, Lodge TP. Micellization of Binary Diblock Co-polymer Mixtures in an Ionic Liquid. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00613] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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28
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König N, Willner L, Pipich V, Zinn T, Lund R. Cooperativity during Melting and Molecular Exchange in Micelles with Crystalline Cores. PHYSICAL REVIEW LETTERS 2019; 122:078001. [PMID: 30848643 DOI: 10.1103/physrevlett.122.078001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/19/2018] [Indexed: 06/09/2023]
Abstract
Molecular exchange processes are important equilibration and transport mechanisms in both synthetic and biological self-assembled systems such as micelles, vesicles, and membranes. Still, these processes are not entirely understood, in particular the effect of crystallinity and the interplay between cooperative melting processes and chain exchange. Here we focus on a set of simple polymer micelles formed by binary mixtures of poly(ethylene oxide)-mono-n-alkyl-ethers (C_{n}-PEO5) which allows the melting point to be tuned over a wide range. We show that the melting transition is cooperative in the confined 4-5 nm micellar core, whereas the exchange process is widely decoupled and unimeric in nature. As confirmed by differential scanning calorimetry, the total activation energy for ejecting a molecule out of the micellar core below the melting point is the sum of the enthalpy of fusion and the corresponding activation energy in the melt state. This suggests that a "local, single-chain melting process" preludes the molecular diffusion out of the micelle during chain exchange.
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Affiliation(s)
- Nico König
- Jülich Centre for Neutron Science (JCNS) and Institute for Complex Systems (ICS), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Lutz Willner
- Jülich Centre for Neutron Science (JCNS) and Institute for Complex Systems (ICS), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Vitaliy Pipich
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, 85747 Garching, Germany
| | - Thomas Zinn
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Reidar Lund
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
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29
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Jones BH, Bachand GD, Shin SHR, Firestone MA, Paxton WF. Dynamic Control over Aqueous Poly(butadiene-b-ethylene oxide) Self-Assembly through Olefin Metathesis. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Millicent A. Firestone
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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