Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition: Core/Corona Structure and Solvent Uptake

Tyler J. Cooksey, Avantika Singh, Kim Mai Le, Shu Wang, Elizabeth G. Kelley, Lilin He, Sameer Vajjala Kesava, Enrique D. Gomez, Bryce E. Kidd, Louis A. Madsen, Megan L. Robertson

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Block copolymer micelles enable the formation of widely tunable self-assembled structures in liquid phases, with applications ranging from drug delivery to personal care products to nanoreactors. In order to understand fundamental aspects of micelle assembly and dynamics, the structural properties and solvent uptake of biocompatible poly(ethylene oxide-b-ϵ-caprolactone) (PEO-PCL) diblock copolymers in deuterated water (D2O)/tetrahydrofuran (THF-d8) mixtures were investigated with a combination of small-angle neutron scattering, nuclear magnetic resonance, and transmission electron microscopy. PEO-PCL block copolymers, of varying molecular weight yet constant block ratio, formed spherical micelles through a wide range of solvent compositions. Varying the solvent composition from 10 to 60 vol % THF-d8 in D2O/THF-d8 mixtures was a convenient means of varying the core-corona interfacial tension in the micelle system. An increase in THF-d8 content in the bulk solvent increased the solvent uptake within the micelle core, which was comparable for the two series, irrespective of the polymer molecular weight. Whereas the smaller molecular weight micelle series exhibited a decrease in aggregation number with increasing THF-d8 content in the bulk solvent, as anticipated due to changes in the core-corona interfacial tension, the aggregation number of the larger molecular weight series was surprisingly invariant with bulk solvent composition. Differences in the dependencies of the micelle size parameters (core radius and overall micelle radius) on the solvent composition originated from the differing trends in aggregation number for the two micelle series. Incorporation of the known unimer content determined from NMR (described in the companion paper), and directly accounting for impacts of solvent swelling of the micelle core on the neutron scattering length density of the core, allowed refinement of and increased confidence in extracted micelle parameters. In summary, the two micelle series showed similar solvent uptake that was independent of the polymer molecular weight yet significantly different dependencies of their aggregation number and size parameters on the solvent composition.

Original languageEnglish (US)
Pages (from-to)4322-4334
Number of pages13
JournalMacromolecules
Volume50
Issue number11
DOIs
StatePublished - Jun 13 2017

Fingerprint

Micelles
Block copolymers
Tuning
Chemical analysis
Molecular weight
Agglomeration
Polyethylene oxides
Neutron scattering
Surface tension
Polymers
Nuclear magnetic resonance
Nanoreactors
Drug delivery
Swelling
Structural properties
Transmission electron microscopy

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Cooksey, T. J., Singh, A., Le, K. M., Wang, S., Kelley, E. G., He, L., ... Robertson, M. L. (2017). Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition: Core/Corona Structure and Solvent Uptake. Macromolecules, 50(11), 4322-4334. https://doi.org/10.1021/acs.macromol.6b02580
Cooksey, Tyler J. ; Singh, Avantika ; Le, Kim Mai ; Wang, Shu ; Kelley, Elizabeth G. ; He, Lilin ; Vajjala Kesava, Sameer ; Gomez, Enrique D. ; Kidd, Bryce E. ; Madsen, Louis A. ; Robertson, Megan L. / Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition : Core/Corona Structure and Solvent Uptake. In: Macromolecules. 2017 ; Vol. 50, No. 11. pp. 4322-4334.
@article{48296e128746455a8976e972c8915918,
title = "Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition: Core/Corona Structure and Solvent Uptake",
abstract = "Block copolymer micelles enable the formation of widely tunable self-assembled structures in liquid phases, with applications ranging from drug delivery to personal care products to nanoreactors. In order to understand fundamental aspects of micelle assembly and dynamics, the structural properties and solvent uptake of biocompatible poly(ethylene oxide-b-ϵ-caprolactone) (PEO-PCL) diblock copolymers in deuterated water (D2O)/tetrahydrofuran (THF-d8) mixtures were investigated with a combination of small-angle neutron scattering, nuclear magnetic resonance, and transmission electron microscopy. PEO-PCL block copolymers, of varying molecular weight yet constant block ratio, formed spherical micelles through a wide range of solvent compositions. Varying the solvent composition from 10 to 60 vol {\%} THF-d8 in D2O/THF-d8 mixtures was a convenient means of varying the core-corona interfacial tension in the micelle system. An increase in THF-d8 content in the bulk solvent increased the solvent uptake within the micelle core, which was comparable for the two series, irrespective of the polymer molecular weight. Whereas the smaller molecular weight micelle series exhibited a decrease in aggregation number with increasing THF-d8 content in the bulk solvent, as anticipated due to changes in the core-corona interfacial tension, the aggregation number of the larger molecular weight series was surprisingly invariant with bulk solvent composition. Differences in the dependencies of the micelle size parameters (core radius and overall micelle radius) on the solvent composition originated from the differing trends in aggregation number for the two micelle series. Incorporation of the known unimer content determined from NMR (described in the companion paper), and directly accounting for impacts of solvent swelling of the micelle core on the neutron scattering length density of the core, allowed refinement of and increased confidence in extracted micelle parameters. In summary, the two micelle series showed similar solvent uptake that was independent of the polymer molecular weight yet significantly different dependencies of their aggregation number and size parameters on the solvent composition.",
author = "Cooksey, {Tyler J.} and Avantika Singh and Le, {Kim Mai} and Shu Wang and Kelley, {Elizabeth G.} and Lilin He and {Vajjala Kesava}, Sameer and Gomez, {Enrique D.} and Kidd, {Bryce E.} and Madsen, {Louis A.} and Robertson, {Megan L.}",
year = "2017",
month = "6",
day = "13",
doi = "10.1021/acs.macromol.6b02580",
language = "English (US)",
volume = "50",
pages = "4322--4334",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "11",

}

Cooksey, TJ, Singh, A, Le, KM, Wang, S, Kelley, EG, He, L, Vajjala Kesava, S, Gomez, ED, Kidd, BE, Madsen, LA & Robertson, ML 2017, 'Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition: Core/Corona Structure and Solvent Uptake', Macromolecules, vol. 50, no. 11, pp. 4322-4334. https://doi.org/10.1021/acs.macromol.6b02580

Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition : Core/Corona Structure and Solvent Uptake. / Cooksey, Tyler J.; Singh, Avantika; Le, Kim Mai; Wang, Shu; Kelley, Elizabeth G.; He, Lilin; Vajjala Kesava, Sameer; Gomez, Enrique D.; Kidd, Bryce E.; Madsen, Louis A.; Robertson, Megan L.

In: Macromolecules, Vol. 50, No. 11, 13.06.2017, p. 4322-4334.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition

T2 - Core/Corona Structure and Solvent Uptake

AU - Cooksey, Tyler J.

AU - Singh, Avantika

AU - Le, Kim Mai

AU - Wang, Shu

AU - Kelley, Elizabeth G.

AU - He, Lilin

AU - Vajjala Kesava, Sameer

AU - Gomez, Enrique D.

AU - Kidd, Bryce E.

AU - Madsen, Louis A.

AU - Robertson, Megan L.

PY - 2017/6/13

Y1 - 2017/6/13

N2 - Block copolymer micelles enable the formation of widely tunable self-assembled structures in liquid phases, with applications ranging from drug delivery to personal care products to nanoreactors. In order to understand fundamental aspects of micelle assembly and dynamics, the structural properties and solvent uptake of biocompatible poly(ethylene oxide-b-ϵ-caprolactone) (PEO-PCL) diblock copolymers in deuterated water (D2O)/tetrahydrofuran (THF-d8) mixtures were investigated with a combination of small-angle neutron scattering, nuclear magnetic resonance, and transmission electron microscopy. PEO-PCL block copolymers, of varying molecular weight yet constant block ratio, formed spherical micelles through a wide range of solvent compositions. Varying the solvent composition from 10 to 60 vol % THF-d8 in D2O/THF-d8 mixtures was a convenient means of varying the core-corona interfacial tension in the micelle system. An increase in THF-d8 content in the bulk solvent increased the solvent uptake within the micelle core, which was comparable for the two series, irrespective of the polymer molecular weight. Whereas the smaller molecular weight micelle series exhibited a decrease in aggregation number with increasing THF-d8 content in the bulk solvent, as anticipated due to changes in the core-corona interfacial tension, the aggregation number of the larger molecular weight series was surprisingly invariant with bulk solvent composition. Differences in the dependencies of the micelle size parameters (core radius and overall micelle radius) on the solvent composition originated from the differing trends in aggregation number for the two micelle series. Incorporation of the known unimer content determined from NMR (described in the companion paper), and directly accounting for impacts of solvent swelling of the micelle core on the neutron scattering length density of the core, allowed refinement of and increased confidence in extracted micelle parameters. In summary, the two micelle series showed similar solvent uptake that was independent of the polymer molecular weight yet significantly different dependencies of their aggregation number and size parameters on the solvent composition.

AB - Block copolymer micelles enable the formation of widely tunable self-assembled structures in liquid phases, with applications ranging from drug delivery to personal care products to nanoreactors. In order to understand fundamental aspects of micelle assembly and dynamics, the structural properties and solvent uptake of biocompatible poly(ethylene oxide-b-ϵ-caprolactone) (PEO-PCL) diblock copolymers in deuterated water (D2O)/tetrahydrofuran (THF-d8) mixtures were investigated with a combination of small-angle neutron scattering, nuclear magnetic resonance, and transmission electron microscopy. PEO-PCL block copolymers, of varying molecular weight yet constant block ratio, formed spherical micelles through a wide range of solvent compositions. Varying the solvent composition from 10 to 60 vol % THF-d8 in D2O/THF-d8 mixtures was a convenient means of varying the core-corona interfacial tension in the micelle system. An increase in THF-d8 content in the bulk solvent increased the solvent uptake within the micelle core, which was comparable for the two series, irrespective of the polymer molecular weight. Whereas the smaller molecular weight micelle series exhibited a decrease in aggregation number with increasing THF-d8 content in the bulk solvent, as anticipated due to changes in the core-corona interfacial tension, the aggregation number of the larger molecular weight series was surprisingly invariant with bulk solvent composition. Differences in the dependencies of the micelle size parameters (core radius and overall micelle radius) on the solvent composition originated from the differing trends in aggregation number for the two micelle series. Incorporation of the known unimer content determined from NMR (described in the companion paper), and directly accounting for impacts of solvent swelling of the micelle core on the neutron scattering length density of the core, allowed refinement of and increased confidence in extracted micelle parameters. In summary, the two micelle series showed similar solvent uptake that was independent of the polymer molecular weight yet significantly different dependencies of their aggregation number and size parameters on the solvent composition.

UR - http://www.scopus.com/inward/record.url?scp=85020713763&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85020713763&partnerID=8YFLogxK

U2 - 10.1021/acs.macromol.6b02580

DO - 10.1021/acs.macromol.6b02580

M3 - Article

AN - SCOPUS:85020713763

VL - 50

SP - 4322

EP - 4334

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 11

ER -