1
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Heo TY, Choi SH. Ionic Strength-Dependent Structure of Complex Coacervate Core Micelles. J Phys Chem B 2024; 128:1256-1265. [PMID: 38288748 DOI: 10.1021/acs.jpcb.3c06004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Salt concentration-dependent structure of complex coacervate core micelles (C3Ms), formed by polyether-based block copolyelectrolytes containing cationic ammonium (A) or anionic sulfonate (S) groups in aqueous media, is investigated by light scattering and small-angle X-ray/neutron scattering (SAX/NS). As the salt concentration increases, both a core radius (Rcore) and an aggregation number (Nagg) significantly decrease, but a corona thickness (Lcorona) is nearly unchanged. Larger salt concentrations can lower the interfacial tension between the coacervate cores and aqueous media, resulting in an increased interfacial area per chain and a more relaxed conformation of the core blocks. Based on the structure characterization, the scaling relationship between structure parameters (i.e., Rcore, Nagg, and Lcorona) and salt concentration is obtained and compared to the theoretical description estimated by the free energy balance between the entropic penalty of core stretching and the interfacial energy. We propose that the free energy contribution of the core block stretching is not negligible in C3Ms because of the highly swollen cores caused by water.
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Affiliation(s)
- Tae-Young Heo
- 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
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2
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Heo TY, Audus DJ, Choi SH. Scaling Relationship of Complex Coacervate Core Micelles: Role of Core Block Stretching. ACS Macro Lett 2023; 12:1396-1402. [PMID: 37782013 DOI: 10.1021/acsmacrolett.3c00347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
The scaling relationship of complex coacervate core micelles (C3Ms) has been investigated experimentally and theoretically. The C3Ms are formed by mixing two oppositely charged block copolyelectrolyte solutions (i.e., AB + AC system) and are characterized by small-angle neutron (SANS) and X-ray scattering (SAXS). Scaling relationships for micellar structure parameters, including core radius, total radius, corona thickness, and aggregation number, all with respect to the core block length, are determined. A scaling theory is also proposed by minimizing the free energy per chain, leading to four regimes depending on the core and corona chain conformations. Although the corona block is significantly longer than the core block, the structure of our C3Ms is consistent with that of the crew-cut I regime. A highly swollen core by water enables the core blocks to be stretched significantly and corona chains to be minimally overlapped.
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Affiliation(s)
- Tae-Young Heo
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Debra J Audus
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Soo-Hyung Choi
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea
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3
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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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4
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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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5
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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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6
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Heo TY, Kim I, Chen L, Lee E, Lee S, Choi SH. Effect of Ionic Group on the Complex Coacervate Core Micelle Structure. Polymers (Basel) 2019; 11:E455. [PMID: 30960439 PMCID: PMC6473896 DOI: 10.3390/polym11030455] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/22/2019] [Accepted: 02/27/2019] [Indexed: 12/16/2022] Open
Abstract
Pairs of ionic group dependence of the structure of a complex coacervate core micelle (C3M) in an aqueous solution was investigated using DLS, cryo-TEM, and SANS with a contrast matching technique and a detailed model analysis. Block copolyelectrolytes were prepared by introducing an ionic group (i.e., ammonium, guanidinium, carboxylate, and sulfonate) to poly(ethylene oxide-b-allyl glycidyl ether) (NPEO = 227 and NPAGE = 52), and C3Ms were formed by simple mixing of two oppositely-charged block copolyelectrolyte solutions with the exactly same degree of polymerization. All four C3Ms are spherical with narrow distribution of micelle dimension, and the cores are significantly swollen by water, resulting in relatively low brush density of PEO chains on the core surface. With the pair of strong polyelectrolytes, core radius and aggregation number increases, which reflects that the formation of complex coacervates are significantly sensitive to the pairs of ionic groups rather than simple charge pairing.
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Affiliation(s)
- Tae-Young Heo
- Department of Chemical Engineering, Hongik University, Seoul 04066, Korea.
| | - Inhye Kim
- Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 34134, Korea.
| | - Liwen Chen
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
| | - Eunji Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
| | - Sangwoo Lee
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
| | - Soo-Hyung Choi
- Department of Chemical Engineering, Hongik University, Seoul 04066, Korea.
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7
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Cooksey TJ, Singh A, Le KM, Wang S, Kelley EG, He L, Vajjala Kesava S, Gomez ED, Kidd BE, Madsen LA, Robertson ML. Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition: Core/Corona Structure and Solvent Uptake. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02580] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Tyler J. Cooksey
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Avantika Singh
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Kim Mai Le
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Shu Wang
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
| | - Elizabeth G. Kelley
- Department
of Chemical Engineering, University of Delaware, Newark, Delaware 19716, United States
- National
Institute
of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland 20899-6100, United States
| | - Lilin He
- Biology
and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Sameer Vajjala Kesava
- Department
of Chemical Engineering and the Materials Research Institute, The Pennsylvania State University, State College, Pennsylvania 16801, United States
| | - Enrique D. Gomez
- Department
of Chemical Engineering and the Materials Research Institute, The Pennsylvania State University, State College, Pennsylvania 16801, United States
| | - Bryce E. Kidd
- Department
of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Louis A. Madsen
- Department
of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Megan L. Robertson
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, United States
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8
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Oparaji O, Zuo X, Hallinan DT. Crystallite dissolution in PEO-based polymers induced by water sorption. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.08.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Ma Y, Lodge TP. Poly(methyl methacrylate)-block-poly(n-butyl methacrylate) Diblock Copolymer Micelles in an Ionic Liquid: Scaling of Core and Corona Size with Core Block Length. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00315] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Yuanchi Ma
- Department of Chemistry and ‡Department of Chemical Engineering
and Materials
Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Timothy P. Lodge
- Department of Chemistry and ‡Department of Chemical Engineering
and Materials
Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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10
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Zhou C, Toombes GES, Wasbrough MJ, Hillmyer MA, Lodge TP. Structure of Two-Compartment Hydrogels from Thermoresponsive ABC Triblock Terpolymers. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00584] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - Gilman E. S. Toombes
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Matthew J. Wasbrough
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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11
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Michaux F, Blin JL, Teixeira J, Stébé MJ. Structural Investigation of Nonionic Fluorinated Micelles by SANS in Relation to Mesoporous Silica Materials. J Phys Chem B 2011; 116:261-8. [DOI: 10.1021/jp209853r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Florentin Michaux
- Equipe Physico-chimie des Colloïdes, UMR SRSMC N° 7565, Université Nancy-1/CNRS Faculté des Sciences, BP 70239, F-54506 Vandoeuvre-les-Nancy cedex, France
| | - Jean-Luc Blin
- Equipe Physico-chimie des Colloïdes, UMR SRSMC N° 7565, Université Nancy-1/CNRS Faculté des Sciences, BP 70239, F-54506 Vandoeuvre-les-Nancy cedex, France
| | - José Teixeira
- Laboratoire Léon Brillouin (CEA/CNRS), CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Marie José Stébé
- Equipe Physico-chimie des Colloïdes, UMR SRSMC N° 7565, Université Nancy-1/CNRS Faculté des Sciences, BP 70239, F-54506 Vandoeuvre-les-Nancy cedex, France
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12
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He L, Wang H, Garamus VM, Hanley T, Lensch M, Gabius HJ, Fee CJ, Middelberg A. Analysis of MonoPEGylated Human Galectin-2 by Small-Angle X-ray and Neutron Scattering: Concentration Dependence of PEG Conformation in the Conjugate. Biomacromolecules 2010; 11:3504-10. [DOI: 10.1021/bm100999a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lizhong He
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
| | - Hui Wang
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
| | - Vasil M. Garamus
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
| | - Tracey Hanley
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
| | - Martin Lensch
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
| | - Hans-Joachim Gabius
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
| | - Conan J. Fee
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
| | - Anton Middelberg
- Australian Institute for Bioengineering and Nanotechnology, Centre for Biomolecular Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia, GKSS Research Centre, D-21502 Geesthacht, Germany, Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights NSW 2234, Australia, Faculty of Veterinary Medicine, Institute for Physiological Chemistry, Ludwig-Maximilians
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13
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Stepánek M, Kosovan P, Procházka K, Janata M, Netopilík M, Plestil J, Slouf M. Self-assembly of poly(4-methylstyrene)-g-poly(methacrylic acid) graft copolymer in selective solvents for grafts: scattering and molecular dynamics simulation study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:9289-9296. [PMID: 20232838 DOI: 10.1021/la1001682] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Poly(4-methylstyrene)-g-poly(methacrylic acid) (P4MS-g-PMAA) graft copolymer was synthesized by the grafting-onto method from poly(4-methylstyrene), selectively brominated on methyl groups, and "living" poly(tert-butyl methacrylate). The average degree of polymerization of the backbone and the grafts and the average number of grafts per backbone were 251, 21, and 25, respectively. The self-assembly of P4MS-g-PMAA was studied in methanol and aqueous buffers (selective solvents for grafts). Micelles of P4MS-g-PMAA in methanol were studied by a combination of static and dynamic light scattering, TEM and SAXS. It was found that their spherical core/shell morphology resembles that of diblock copolymer micelles but they have a very low aggregation number (approximately 3) and a high cmc (approximately 0.8 mg/mL). The spherical core-shell structure revealed by SAXS was confirmed by the molecular dynamics study emulating an associate of comblike copolymers with structural parameters close to those of the experimentally studied system. Because P4MS-g-PMAA was not directly soluble in water, its aqueous solutions had to be prepared by dialysis of the methanolic solutions. In aqueous solutions, unlike in methanol, small P4MS-g-PMAA micelles (approximately 20 nm in diameter) form large secondary aggregates (approximately 100-400 nm).
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Affiliation(s)
- Miroslav Stepánek
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 12840 Prague 2, Czech Republic.
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14
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Taribagil RR, Hillmyer MA, Lodge TP. Hydrogels from ABA and ABC Triblock Polymers. Macromolecules 2010. [DOI: 10.1021/ma100464z] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Timothy P. Lodge
- Department of Chemical Engineering & Materials Science
- Department of Chemistry
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15
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Choi SH, Bates FS, Lodge TP. Structure of poly(styrene-b-ethylene-alt-propylene) diblock copolymer micelles in squalane. J Phys Chem B 2010; 113:13840-8. [PMID: 19320497 DOI: 10.1021/jp8111149] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The temperature dependence of the micellar structures formed by poly(styrene-b-ethylene-alt-propylene) (SEP) diblock copolymers in squalane, a highly selective solvent for the PEP blocks, has been studied using dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS). Four SEP diblock copolymers were prepared by sequential anionic polymerization of styrene and isoprene, followed by hydrogenation of the isoprene blocks, to yield SEP(17-73), SEP(26-66), SEP(36-69), and SEP(42-60), where the numbers indicate block molecular weights in kDa. All four polymers formed well-defined spherical micelles. In dilute solution, DLS provided the temperature-dependent mean hydrodynamic radius, R(h), and its distribution, while detailed fitting of the SAXS profiles gave the core radius, R(c), the equivalent hard sphere radius, R(hs), and an estimate of the aggregation number, N(agg). In general, the micelles became smaller as the critical micelle temperature (CMT) was approached, which was well above the glass transition of the core block. As concentration increased the micelles packed onto body centered cubic lattices for all four copolymers, which underwent order-disorder transitions upon heating near the dilute solution CMTs. The results are discussed in terms of current understanding of block copolymer solution self-assembly, and particular attention is paid to the issue of equilibration, given the high glass transition temperature of the core block.
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Affiliation(s)
- Soo-Hyung Choi
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
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16
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Lund R, Willner L, Lindner P, Richter D. Structural Properties of Weakly Segregated PS−PB Block Copolymer Micelles in n-Alkanes: Solvent Entropy Effects. Macromolecules 2009. [DOI: 10.1021/ma8021629] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Reidar Lund
- Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany, and Institut Laue-Langevin, B.P. 156X, Avenue des Martyrs, F-38042 Grenoble Cedex 9, France
| | - Lutz Willner
- Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany, and Institut Laue-Langevin, B.P. 156X, Avenue des Martyrs, F-38042 Grenoble Cedex 9, France
| | - Peter Lindner
- Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany, and Institut Laue-Langevin, B.P. 156X, Avenue des Martyrs, F-38042 Grenoble Cedex 9, France
| | - Dieter Richter
- Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany, and Institut Laue-Langevin, B.P. 156X, Avenue des Martyrs, F-38042 Grenoble Cedex 9, France
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17
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Diblock copolymers of ethylene oxide and 1,2-butylene oxide in aqueous solution. Int J Pharm 2008; 362:193-6. [DOI: 10.1016/j.ijpharm.2008.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 06/02/2008] [Accepted: 06/04/2008] [Indexed: 11/20/2022]
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18
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Castelletto V, Newby GE, Hamley IW, Noirez L, Baroni P. Pressure effects revealed by small angle neutron scattering on block copolymer gels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8319-8324. [PMID: 18564866 DOI: 10.1021/la801025n] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We study the effects of hydrostatic pressure (P) on aqueous solutions and gels of the block copolymer B(20)E(610) (E, oxyethylene; B, oxybutylene; subscripts, number of repeats), by performing simultaneous small angle neutron scattering/pressure experiments. Micellar cubic gels were studied for 9.5 and 4.5 wt % B(20)E(610) at T = 20-80 and 35-55 degrees C, respectively, while micellar isotropic solutions where studied for 4.5 wt % B(20)E(610) at T > 55 degrees C. We observed that the interplanar distance d 110 (cubic unit cell parameter a = [see text for formula]) decreases while the correlation length of the cubic order (delta) increases, upon increasing P at a fixed T for 9.5 wt % B(20)E(610). The construction of master curves for d(110) and delta corresponding to 9.5 wt % B(20)E(610) proved the correlation between changes in T and P. Neither d(110) and delta nor the cubic-isotropic phase transition temperature was affected by the applied pressure for 4.5 wt % B(20)E(610). The dramatic contrast between the pressure-induced behavior observed for 9.5 and 4.5 wt % B(20)E(610) suggests that pressure induced effects might be more effectively transmitted through samples that present wider domains of cubic structure order (9.5 wt % compared to 4.5 wt % B(20)E(610)).
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Affiliation(s)
- V Castelletto
- School of Chemistry, Food Biosciences and Pharmacy, The University of Reading, P.O. Box 226, Whiteknights, Reading, UK.
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Castro E, Barbosa S, Juárez J, Taboada P, Katime IA, Mosquera V. Influence of External Factors on the Micellization Process and Aggregate Structure of Poly(oxy)styrene−Poly(oxy)ethylene Block Copolymers. J Phys Chem B 2008; 112:5296-304. [DOI: 10.1021/jp7112895] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emilio Castro
- Grupo de Física de Coloides y Polímeros, Grupo de Sistemas Complejos, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, and Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Departamento de Química-Física, Facultad de Ciencia y Tecnología, Campus de Leioa, Universidad del País Vasco, Apartado 644, Bilbao, Spain
| | - Silvia Barbosa
- Grupo de Física de Coloides y Polímeros, Grupo de Sistemas Complejos, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, and Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Departamento de Química-Física, Facultad de Ciencia y Tecnología, Campus de Leioa, Universidad del País Vasco, Apartado 644, Bilbao, Spain
| | - Josué Juárez
- Grupo de Física de Coloides y Polímeros, Grupo de Sistemas Complejos, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, and Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Departamento de Química-Física, Facultad de Ciencia y Tecnología, Campus de Leioa, Universidad del País Vasco, Apartado 644, Bilbao, Spain
| | - Pablo Taboada
- Grupo de Física de Coloides y Polímeros, Grupo de Sistemas Complejos, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, and Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Departamento de Química-Física, Facultad de Ciencia y Tecnología, Campus de Leioa, Universidad del País Vasco, Apartado 644, Bilbao, Spain
| | - Issa A. Katime
- Grupo de Física de Coloides y Polímeros, Grupo de Sistemas Complejos, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, and Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Departamento de Química-Física, Facultad de Ciencia y Tecnología, Campus de Leioa, Universidad del País Vasco, Apartado 644, Bilbao, Spain
| | - Víctor Mosquera
- Grupo de Física de Coloides y Polímeros, Grupo de Sistemas Complejos, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, and Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Departamento de Química-Física, Facultad de Ciencia y Tecnología, Campus de Leioa, Universidad del País Vasco, Apartado 644, Bilbao, Spain
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Durkee DA, Gomez ED, Ellsworth MW, Bell AT, Balsara NP. Microstructure and Solvent Distribution in Cross-Linked Diblock Copolymer Gels. Macromolecules 2007. [DOI: 10.1021/ma0629485] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D. A. Durkee
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Materials Sciences Division, Environmental Energy Technologies Division, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720; and Tyco Electronics Corporation, Menlo Park, California 94025
| | - E. D. Gomez
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Materials Sciences Division, Environmental Energy Technologies Division, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720; and Tyco Electronics Corporation, Menlo Park, California 94025
| | - M. W. Ellsworth
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Materials Sciences Division, Environmental Energy Technologies Division, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720; and Tyco Electronics Corporation, Menlo Park, California 94025
| | - A. T. Bell
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Materials Sciences Division, Environmental Energy Technologies Division, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720; and Tyco Electronics Corporation, Menlo Park, California 94025
| | - N. P. Balsara
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Materials Sciences Division, Environmental Energy Technologies Division, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720; and Tyco Electronics Corporation, Menlo Park, California 94025
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21
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Castro E, Taboada P, Mosquera V. Cosolvent Effects on the Micellization of Oxyphenyl(copoly)ethylene Oxide Copolymers in Aqueous Solution. J Phys Chem B 2006; 110:13113-23. [PMID: 16805622 DOI: 10.1021/jp061322d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the present paper, we have analyzed how the presence of ethanol affects the micellization process of two structurally related polyoxyethylene block copolymers with diblock and triblock architectures (diblock, S15E63; triblock, E67S15E67) and the same hydrophobic block length, formed by oxyphenylethylene units, through surface tension, static and dynamic light scattering, density, ultrasound velocity, transmission electron microscopy, and steady-state fluorescence techniques. E and S denote the oxyethylene (-OCH2CH2) and oxyphenylethylene (-OCH2CH(C6H5)) units, respectively, and the subscripts the block length. The effect of increasing amounts of ethanol in solution gives rise to a progressive disruption of the micelle structures formed by these copolymers, with an increase in the critical micelle concentration (cmc) values and a decrease in the micellar aggregation number. This originated from the deswelling of the poly(ethylene oxide) (PEO) chains due to a decrease of the water content, accompanied by a reduction of the solvophobicity and an increase of the solubility of the S blocks, causing the lowering of the interfacial tension between the polyoxyphenylethylene core and the solvent, and favoring the swelling of hydrophobic blocks. Therefore, to achieve thermodynamic equilibrium, the micelle size should be smaller. A model derived from small angle neutron scattering (SANS) data is also applied to get extra information on micelle structure. With the aim of obtaining information about the hydration of micellar solutions of these block copolymers, compressibility and fluorescence data were collected. The increase of compressibility with ethanol addition confirms the swelling of the hydrophobic polyoxyphenylethylene chains. Fluorescence data show that the addition of ethanol to the solution decreases the polarity, favoring the solubilization of the oxyphenylethylene chains in the mixed solvent as single monomers. Aggregation data derived from this technique are in fair agreement with those obtained from light scattering.
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Affiliation(s)
- Emilio Castro
- Laboratorio de Física de Coloides y Polímeros, Grupo de Sistemas Complejos, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, Spain
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22
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Bang J, Jain S, Li Z, Lodge TP, Pedersen JS, Kesselman E, Talmon Y. Sphere, Cylinder, and Vesicle Nanoaggregates in Poly(styrene-b-isoprene) Diblock Copolymer Solutions. Macromolecules 2006. [DOI: 10.1021/ma052023+] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Castelletto V, Hamley IW, Yuan XF, Kelarakis A, Booth C. Structure and rheology of aqueous micellar solutions and gels formed from an associative poly(oxybutylene)-poly(oxyethylene)-poly(oxybutylene) triblock copolymer. SOFT MATTER 2005; 1:138-145. [PMID: 32521837 DOI: 10.1039/b419103j] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The structure and shear flow behaviour of aqueous micellar solutions and gels formed by an amphiphilic poly(oxybutylene)-poly(oxyethylene)-poly(oxybutylene) triblock copolymer with a lengthy hydrophilic poly(oxyethylene) block has been investigated by rheology, small angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS). SANS revealed that bridging of chains between micelles introduces, in the micellar solution, an attractive long-range component which can be described through a potential of interaction corresponding to sticky soft spheres. The strength of the attractive interaction increases with increasing concentration. Rheology showed that the dependence of the storage modulus with temperature can be explained as a function of the micellar bridging, micellisation and phase morphology. SAXS studies showed that the orientation adopted by the system in the gel phase under shear is similar to that previously observed by us for the gel phase of a poly(oxyethylene)-poly(oxybutylene) diblock copolymer with a long poly(oxyethylene) chain, suggesting that the micellar corona/core length ratio and not the architecture of the block copolymer influences the alignment of the gel phase under shear.
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Affiliation(s)
- V Castelletto
- Dept of Chemistry and Centre for Self-Organising Molecular Systems, University of Leeds, Leeds LS2 9JT, UK.
| | - I W Hamley
- Dept of Chemistry and Centre for Self-Organising Molecular Systems, University of Leeds, Leeds LS2 9JT, UK.
| | - X-F Yuan
- School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD, UK
| | - A Kelarakis
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - C Booth
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
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Sommer C, Pedersen JS, Garamus VM. Structure and interactions of block copolymer micelles of Brij 700 studied by combining small-angle X-ray and neutron scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:2137-49. [PMID: 15752000 DOI: 10.1021/la047489k] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Spherical micelles of the diblock copolymer/surfactant Brij 700 (C(18)EO(100)) in water (D(2)O) solution have been investigated by small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS). SAXS and SANS experiments are combined to obtain complementary information from the two different contrast conditions of the two techniques. Solutions in a concentration range from 0.25 to 10 wt % and at temperatures from 10 to 80 degrees C have been investigated. The data have been analyzed on absolute scale using a model based on Monte Carlo simulations, where the micelles have a spherical homogeneous core with a graded interface surrounded by a corona of self-avoiding, semiflexible interacting chains. SANS and SAXS data were fitted simultaneously, which allows one to obtain extensive quantitative information on the structure and profile of the core and corona, the chain interactions, and the concentration effects. The model describes the scattering data very well, when part of the EO chains are taken as a "background"contribution belonging to the solvent. The effect of this becomes non-negligible at polymer concentrations as low as 2 wt %, where overlap of the micellar coronas sets in. The results from the analysis on the micellar structure, interchain interactions, and structure factor effects are all consistent with a decrease in solvent quality of water for the PEO block as the theta temperature of PEO is approached.
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Affiliation(s)
- Cornelia Sommer
- Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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Bendejacq DD, Ponsinet V, Joanicot M. Chemically tuned amphiphilic diblock copolymers dispersed in water: from colloids to soluble macromolecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:1712-1718. [PMID: 15723464 DOI: 10.1021/la048983r] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We investigate by small-angle scattering the structural behavior in water of a family of asymmetric poly(styrene-stat-(acrylic acid))-block-poly(acrylic acid), i.e., P(S-stat-AA)-b-PAA, diblock copolymers. These diblocks are of constant block ratio and increasing molar fraction, phi(AA), ranging from 0 to 1, of acrylic acid in the first P(S-stat-AA) statistical block. We identify three types of structural behavior in water: (i) for phi(AA) </= 0.25, the structures found in water are out-of-equilibrium micelle-like objects, reminiscent of the macrophase separation in the solid state, with no reorganization upon dispersion; (ii) for phi(AA) >/= 0.50, the diblocks dispersions in water are at equilibrium. For high phi(AA), the diblocks are soluble in water, demonstrating that a transition from colloid-like objects to soluble macromolecules is achieved. Close to the transition, (phi(AA) approximately 0.50), the diblocks form objects interpreted as comprising a water-swollen core formed by the P(S-stat-AA) block, surrounded by a swollen brush composed of the majority PAA block, above a apparent critical micelle concentration. However, these diblocks do not behave as macrosurfactants, and their self-association behavior is rather interpreted as a microphase separation which can arise from the incompatibility between two polymer blocks P(S-stat-AA) and PAA placed in a common solvent water.
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Affiliation(s)
- Denis D Bendejacq
- Complex Fluids Laboratory, UMR 166 CNRS/Rhodia, Cranbury, New Jersey 08512, USA
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26
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Fick J, Steitz R, Leiner V, Tokumitsu S, Himmelhaus M, Grunze M. Swelling behavior of self-assembled monolayers of alkanethiol-terminated poly(ethylene glycol): a neutron reflectometry study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:3848-53. [PMID: 15969370 DOI: 10.1021/la049526d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The swelling behavior of alkanethiol-terminated poly(ethylene glycol) with an average molecular weight of 2180 Da (i.e., approximately 45 ethylene glycol, EG, units) in contact with water was investigated by neutron reflectometry as a function of the morphology of the PEG-SH layer. Amorphous films at a low grafting density show significant swelling with an increase of the film thickness from approximately 25 A in the dry state to approximately 70 A in contact with D2O, which corresponds to a total water uptake of approximately 38 mass %. In contrast, quasi-crystalline monolayers exhibit only a small amount of water penetrating into the film (approximately 8 mass %) with a corresponding change of the layer thickness from approximately 110 to approximately 125 A. The water uptake per EG unit corresponds to the literature value of 1.5 for the amorphous layer and to only 0.25 in the case of the quasi-crystalline film.
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Sommer C, Pedersen JS, Stein PC. Apparent Specific Volume Measurements of Poly(ethylene oxide), Poly(butylene oxide), Poly(propylene oxide), and Octadecyl Chains in the Micellar State as a Function of Temperature. J Phys Chem B 2004; 108:6242-9. [DOI: 10.1021/jp036963c] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cornelia Sommer
- Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Jan Skov Pedersen
- Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Paul C. Stein
- Department of Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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Lodge TP, Bang J, Park MJ, Char K. Origin of the thermoreversible fcc-bcc transition in block copolymer solutions. PHYSICAL REVIEW LETTERS 2004; 92:145501. [PMID: 15089548 DOI: 10.1103/physrevlett.92.145501] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2003] [Indexed: 05/12/2023]
Abstract
The thermoreversible fcc-bcc transition in concentrated block copolymer micellar solutions is shown to be driven by decreases in the aggregation number as the solvent penetrates the core, leading to a softer intermicelle potential. Small-angle neutron scattering measurements in a dilute solution are used to quantify the temperature-dependent micellar characteristics. The observed phase boundary is in excellent agreement with recent simulations of highly branched star polymers.
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Affiliation(s)
- Timothy P Lodge
- Department of Chemical Engineering & Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Castelletto V, Hamley IW, Pedersen JS. Small-angle neutron scattering study of the structure of superswollen micelles formed by a highly asymmetric poly(oxybutylene)-poly(oxyethylene) diblock copolymer in aqueous solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:2992-2994. [PMID: 15835187 DOI: 10.1021/la036231b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Affiliation(s)
- V Castelletto
- Department of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
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30
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Sommer C, Pedersen JS. Temperature Dependence of the Structure and Interaction of Starlike PEG-Based Block Copolymer Micelles. Macromolecules 2004. [DOI: 10.1021/ma0357669] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cornelia Sommer
- Department of Chemistry and iNANO Interdisciplinary Nanoscience Center, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Jan Skov Pedersen
- Department of Chemistry and iNANO Interdisciplinary Nanoscience Center, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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Bang J, Viswanathan K, Lodge TP, Park MJ, Char K. Temperature-dependent micellar structures in poly(styrene-b-isoprene) diblock copolymer solutions near the critical micelle temperature. J Chem Phys 2004; 121:11489-500. [PMID: 15634109 DOI: 10.1063/1.1812753] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The temperature dependence of the micelle structures formed by poly(styrene-b-isoprene) (SI) diblock copolymers in the selective solvents diethyl phthalate (DEP) and tetradecane (C14), which are selective for the PS and PI blocks, respectively, have been investigated by small angle neutron scattering (SANS). Two nearly symmetric SI diblock copolymers, one with a perdeuterated PS block and the other with a perdeuterated PI block, were examined in both DEP and C14. The SANS scattering length density of the solvent was matched closely to either the core or the corona block. The resulting core and corona contrast data were fitted with a detailed model developed by Pedersen and co-workers. The fits provide quantitative information on micellar characteristics such as aggregation number, core size, overall size, solvent fraction in the core, and corona thickness. As temperature increases, the solvent selectivity decreases, leading to substantial solvent swelling of the core and a decrease in the aggregation number and core size. Both core and corona chains are able to relax their conformations near the critical micelle temperature due to a decrease in the interfacial tension, even though the corona chains are always under good solvent conditions.
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Affiliation(s)
- Joona Bang
- Department of Chemical Engineering & Materials Science, University of Minnesota, Minneapolis, MN 55455-0431, USA
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