Tale of Two Tails: Molecular Exchange Kinetics of Telechelic Polymer Micelles

König, Nico; Willner, Lutz; Pipich, Vitaliy; Mahmoudi, Najet; Lund, Reidar

doi:10.1103/physrevlett.124.197801

Cited by 10 publications

(14 citation statements)

References 202 publications

(401 reference statements)

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“…In addition, the broad range of exchange rates might not only be caused by polydispersity of the chains. Computer simulations on amphiphilic block copolymer micelles have suggested that logarithmic relaxation can even occur for monodisperse chains, although in experiments with monodisperse core blocks, this logarithmic relaxation has not been observed. ,, The logarithmic relaxation in the computer simulations was explained by degeneracy of the energy states of the core blocks, which is broken when the chain leaves the core. If these degeneracy effects indeed could play a role in the exchange of amphiphilic diblock copolymer micelles, they might also play a role here.…”

Section: Resultsmentioning

confidence: 91%

FRET-Based Determination of the Exchange Dynamics of Complex Coacervate Core Micelles

2020

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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 Forster 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.

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Section: Resultsmentioning

confidence: 91%

FRET-Based Determination of the Exchange Dynamics of Complex Coacervate Core Micelles

2020

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“…(bottom) TR-SANS data of C 28 -PEO5/C 28 -PEO10-C 28 micelles obtained after mixing equal amounts of deuterated and protonated micelle solutions. Reproduced with permission from ref . Copyright 2020 American Physical Society.…”

Section: Deuteration and Neutron Scatteringmentioning

confidence: 99%

Deuteration and Polymers: Rich History with Great Potential

Jakowski

et al. 2021

Macromolecules

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Deuterium, a stable hydrogen isotope, has been playing important roles in many scientific areas, including polymer science. The developments of deuteration science and polymer science have been interwoven for the past 60 years. The unique characteristics of the scattering lengths for hydrogen isotopes (protium and deuterium) result in the dramatic differences of scattering length densities for protiated and deuterated compounds omnipresent in polymers, rendering neutron scattering a powerful tool for the investigation of polymeric structures and dynamics that are inaccessible to other tools. While the role of deuteration in neutron scattering of polymeric materials can hardly be overstated, it has also enabled the addressing of many questions using other approaches, such as NMR and vibrational spectra. In this Perspective, we provide a brief account of deuterium in the synthesis, properties, and application of various polymers. We also offer an outlook of the potentials in this ever-evolving and exciting area.

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“…A structural study of telechelic poly(ethylene oxide) (PEO) chains in a dilute regime 6 has confirmed the formation of flower-like micelles for sufficiently high fraction of alkyl length of hydrophobic end blocks, leading to strong attraction of the hydrophobic groups and formation of clustered micelles with the presence of free dangling ends, when this attraction is reduced by reducing the alkyl length. In turn, a study 8 of the molecular exchange kinetics between micelles suggests a multi-step process of liberating the ends. However, topological transition between individual flower-like and star-like micelles in an extremely dilute regime is expected, 6 but has not been yet studied systematically.…”

Section: Introductionmentioning

confidence: 99%

“…pc(p, m) , (7) where c(m, p) is the number concentration of micelles composed of p tri-block copolymers and containing m free ends, V is the volume of the system. The last term fixes the total concentration of copolymers in the system c 0 , and the corresponding Lagrange multiplier µ 0 .…”

mentioning

confidence: 99%

Topological changes in telechelic micelles: flowers versus stars

Baulin

2021

Preprint

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Micellization and morphology of spherical telechelic micelles formed by tri-block copolymers with short solvophobic end blocks at low concentrations is discussed within scaling arguments and Single Chain Mean Field Theory (SCMFT). In ultra-dilute regime, individual telechelic polymer chains can exist in solution in two distinct states: open linear chain conformation with two free ends and closed loop conformation, when two ends are connected by the effective attraction between two solvophobic ends. At concentrations below gelation point, closed loops tend to form micelles comprised mostly of loops in flower-like micelles, while linear polymers in open conformations tend to form star-shaped aggregates with one hydrophobic dangling end. Resulting two kinds of micelles have remarkably different topology and dimensions, while the transition between them can be driven by the entropy, namely conformation changes between domination of the looped and linear conformations. As a result, the transition between two types of micelles lies in a narrow interaction parameters range. Thus, these topological micelles are very sensitive to the changes in external environment and they can serve as a very sensitive stimuli-responsive smart materials.

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Tale of Two Tails: Molecular Exchange Kinetics of Telechelic Polymer Micelles

Abstract: This thesis is submitted in partial fulfillment of the requirements for the degree of Philosophiae Doctor at the University of Oslo. It comprises five scientific articles, three of which have already been published in peer-reviewed journals.

Cited by 10 publications

References 202 publications

FRET-Based Determination of the Exchange Dynamics of Complex Coacervate Core Micelles

FRET-Based Determination of the Exchange Dynamics of Complex Coacervate Core Micelles

Deuteration and Polymers: Rich History with Great Potential

Topological changes in telechelic micelles: flowers versus stars

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