1
|
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.
Collapse
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
| |
Collapse
|
2
|
Ding M, Hou L, Duan X, Shi T, Li W, Shi AC. Translocation of Micelles through a Nanochannel. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mingming Ding
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Lei Hou
- State Key Laboratory of Molecular Engineering of Polymers, Key Laboratory of Computational Physical Sciences, Department of Macromolecular Science, Fudan University, Shanghai 200433, P. R. China
| | - Xiaozheng Duan
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Tongfei Shi
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Weihua Li
- State Key Laboratory of Molecular Engineering of Polymers, Key Laboratory of Computational Physical Sciences, Department of Macromolecular Science, Fudan University, Shanghai 200433, P. R. China
| | - An-Chang Shi
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| |
Collapse
|
3
|
Pantelidou M, García Daza FA, Avalos JB, Mackie AD. Universal Scaling for the Exit Dynamics of Block Copolymers from Micelles at Short and Long Time Scales. Macromolecules 2022; 55:914-927. [PMID: 35177871 PMCID: PMC8842487 DOI: 10.1021/acs.macromol.1c02387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/01/2022] [Indexed: 11/29/2022]
Abstract
The correlation function for the exit of poloxamer copolymers from equilibrated micelles is found to show up to four regimes depending on the chain flexibility: an initial fast reorganization, a logarithmic intermediate regime, followed by an exponential intermediate regime, and a final exponential decay. The logarithmic intermediate regime has been observed experimentally and attributed to the polydispersity of the polymer samples. However, we present dynamic single-chain mean-field theory simulations with chains of variable flexibility which show the same logarithmic relaxation but with strictly monodisperse systems. In agreement with our previous studies, we propose that this logarithmic response arises from a degeneracy of energy states of the hydrophobic block in the micelle core. For this to occur, a sufficiently large number of degenerate conformational states are required, which depend on the polymer flexibility and therefore should not be present for rigid polymers. Experimental results for monodisperse polymeric samples claiming the absence of such a logarithmic response may also lack a sufficient number of hydrophobic blocks for the required number of configurational states for this type of response to be seen. The insight gained from analyzing the simulation results allows us to propose a modified Eyring equation capable of reproducing the observed dynamic behavior. On scaling experimental results from different sources and systems according to this equation, we find a unique master curve showing a universal nature of the intermediate regimes: the logarithmic regime together with the secondary exponential decay. The terminal exponential regime at long times proposed by the standard Halperin and Alexander model is beyond the range of the data analyzed in this article. The universality observed suggests an entropic origin of the short-time dynamic response of this class of systems rather than the polydispersity.
Collapse
Affiliation(s)
- Maria
S. Pantelidou
- Departament
d’Enginyeria Química, ETSEQ, Universitat Rovira i Virgili, Tarragona 43007, Spain
| | - Fabián A. García Daza
- Department
of Chemical Engineering, The University
of Manchester, Manchester M13 9PL, United Kingdom
| | - Josep Bonet Avalos
- Departament
d’Enginyeria Química, ETSEQ, Universitat Rovira i Virgili, Tarragona 43007, Spain
| | - Allan D. Mackie
- Departament
d’Enginyeria Química, ETSEQ, Universitat Rovira i Virgili, Tarragona 43007, Spain
| |
Collapse
|
4
|
Ziolek RM, Smith P, Pink DL, Dreiss CA, Lorenz CD. Unsupervised Learning Unravels the Structure of Four-Arm and Linear Block Copolymer Micelles. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert M. Ziolek
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Paul Smith
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Demi L. Pink
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Cécile A. Dreiss
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, U.K
| | - Christian D. Lorenz
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| |
Collapse
|
5
|
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
| |
Collapse
|
6
|
Bos I, Timmerman M, Sprakel J. FRET-Based Determination of the Exchange Dynamics of Complex Coacervate Core Micelles. Macromolecules 2021; 54:398-411. [PMID: 33456072 PMCID: PMC7808214 DOI: 10.1021/acs.macromol.0c02387] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/08/2020] [Indexed: 02/07/2023]
Abstract
Complex coacervate core micelles (C3Ms) are nanoscopic structures formed by charge interactions between oppositely charged macroions and used to encapsulate a wide variety of charged (bio)molecules. In most cases, C3Ms are in a dynamic equilibrium with their surroundings. Understanding the dynamics of molecular exchange reactions is essential as this determines the rate at which their cargo is exposed to the environment. Here, we study the molecular exchange in C3Ms by making use of Förster resonance energy transfer (FRET) and derive an analytical model to relate the experimentally observed increase in FRET efficiency to the underlying macromolecular exchange rates. We show that equilibrated C3Ms have a broad distribution of exchange rates. The overall exchange rate can be strongly increased by increasing the salt concentration. In contrast, changing the unlabeled homopolymer length does not affect the exchange of the labeled homopolymers and an increase in the micelle concentration only affects the FRET increase rate at low micelle concentrations. Together, these results suggest that the exchange of these equilibrated C3Ms occurs mainly by expulsion and insertion, where the rate-limiting step is the breaking of ionic bonds to expel the chains from the core. These are important insights to further improve the encapsulation efficiency of C3Ms.
Collapse
Affiliation(s)
- Inge Bos
- Physical Chemistry and Soft
Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Marga Timmerman
- Physical Chemistry and Soft
Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Joris Sprakel
- Physical Chemistry and Soft
Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| |
Collapse
|
7
|
Campos-Villalobos G, Siperstein FR, Charles A, Patti A. Solvent-induced morphological transitions in methacrylate-based block-copolymer aggregates. J Colloid Interface Sci 2020; 572:133-140. [PMID: 32240786 DOI: 10.1016/j.jcis.2020.03.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/25/2020] [Accepted: 03/18/2020] [Indexed: 01/28/2023]
Abstract
Poly(ethylene oxide)-b-poly(butylmethacrylate) (PEO-b-PBMA) copolymers have recently been identified as excellent building blocks for the synthesis of hierarchical nanoporous materials. Nevertheless, while experiments have unveiled their potential to form bicontinuous phases and vesicles, a general picture of their phase and aggregation behavior is still missing. By performing Molecular Dynamics simulations, we here apply our recent coarse-grained model of PEO-b-PBMA to investigate its self-assembly in water and tetrahydrofuran (THF) and unveil the occurrence of a wide spectrum of mesophases. In particular, we find that the morphological phase diagram of this ternary system incorporates bicontinuous and lamellar phases at high copolymer concentrations, and finite-size aggregates, such as dispersed sheets or disk-like aggregates, spherical vesicles and rod-like vesicles, at low copolymer concentrations. The morphology of these mesophases can be controlled by tuning the THF/water relative content, which has a striking effect on the kinetics of self-assembly as well as on the resulting equilibrium structures. Our results disclose the fascinating potential of PEO-b-PBMA copolymers for the templated synthesis of nanostructured materials and offer a guideline to fine-tune their properties by accurately selecting the THF/water ratio.
Collapse
Affiliation(s)
- Gerardo Campos-Villalobos
- Department of Chemical Engineering and Analytical Science, University of Manchester, Sackville Street, Manchester M13 9PL, UK
| | - Flor R Siperstein
- Department of Chemical Engineering and Analytical Science, University of Manchester, Sackville Street, Manchester M13 9PL, UK
| | - Arvin Charles
- Department of Chemical Engineering and Analytical Science, University of Manchester, Sackville Street, Manchester M13 9PL, UK
| | - Alessandro Patti
- Department of Chemical Engineering and Analytical Science, University of Manchester, Sackville Street, Manchester M13 9PL, UK.
| |
Collapse
|
8
|
García Daza FA, Cuetos A, Patti A. Dynamic Monte Carlo simulations of inhomogeneous colloidal suspensions. Phys Rev E 2020; 102:013302. [PMID: 32795071 DOI: 10.1103/physreve.102.013302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
The dynamic Monte Carlo (DMC) method is an established molecular simulation technique for the analysis of the dynamics in colloidal suspensions. An excellent alternative to Brownian dynamics or molecular dynamics simulation, DMC is applicable to systems of spherical and/or anisotropic particles and to equilibrium or out-of-equilibrium processes. In this work, we present a theoretical and methodological framework to extend DMC to the study of heterogeneous systems, where the presence of an interface between coexisting phases introduces an additional element of complexity in determining the dynamic properties. In particular, we simulate a Lennard-Jones fluid at the liquid-vapor equilibrium and determine the diffusion coefficients in the bulk of each phase and across the interface. To test the validity of our DMC results, we also perform Brownian Dynamics simulations and unveil an excellent quantitative agreement between the two simulation techniques.
Collapse
Affiliation(s)
- Fabián A García Daza
- Department of Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Alejandro Cuetos
- Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, 41013 Sevilla, Spain
| | - Alessandro Patti
- Department of Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL, United Kingdom
| |
Collapse
|
9
|
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
| |
Collapse
|