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Seong HG, Jin Z, Chen Z, Hu M, Emrick T, Russell TP. Bottlebrush Block Copolymers at the Interface of Immiscible Liquids: Adsorption and Lateral Packing. J Am Chem Soc 2024; 146:13000-13009. [PMID: 38710503 DOI: 10.1021/jacs.3c13817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Amphiphilic bottlebrush block copolymers (BBCPs), having a hydrophilic bottlebrush polymer (BP) linked covalently to a hydrophobic BP, were found to segregate to liquid-liquid interfaces to minimize the free energy of the system. The key parameter influencing the outcome of the experiments is the ratio between the degree of polymerization of the backbone (NBB) and that of the side-chain brushes (NSC). Specifically, a spherical, star-like configuration results when NBB < NSC, while a cylindrical, bottlebrush-like shape is preferred when NBB > NSC. Dynamic interfacial tension (γ) and fluorescence recovery after photobleaching (FRAP) measurements show that the BBCP configuration influences the areal density and in-plane diffusion at the fluid interface. The characteristic relaxation times associated with BBCP adsorption (τA) and reorganization (τR) were determined by fitting time-dependent interfacial tension measurements to a sum of two exponential relaxation functions. Both τA and τR initially increased with NBB up to 92 repeat units, due to the larger hydrodynamic radius in solution and slower in-plane diffusivity, attributed to a shorter cross-sectional diameter of the side-chains near the block junction. This trend reversed at NBB = 190, with shorter τA and τR attributed to increased segregation strength and exposure of the bare water/toluene interface due to tilting and/or wiggling of the backbone chains, respectively. The adsorption energy barrier decreased with higher NBB, due to a reduced BBCP packing density at the fluid interface. This study provides fundamental insights into macromolecular assembly at fluid interfaces, as it pertains to unique bottlebrush block architectures.
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Affiliation(s)
- Hong-Gyu Seong
- Polymer Science & Engineering Department, Conte Center for Polymer Research, University of Massachusetts, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Zichen Jin
- Polymer Science & Engineering Department, Conte Center for Polymer Research, University of Massachusetts, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Zhan Chen
- Polymer Science & Engineering Department, Conte Center for Polymer Research, University of Massachusetts, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Mingqiu Hu
- Polymer Science & Engineering Department, Conte Center for Polymer Research, University of Massachusetts, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Todd Emrick
- Polymer Science & Engineering Department, Conte Center for Polymer Research, University of Massachusetts, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Thomas P Russell
- Polymer Science & Engineering Department, Conte Center for Polymer Research, University of Massachusetts, 120 Governors Drive, Amherst, Massachusetts 01003, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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2
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Vilgis TA. Soft matter food physics--the physics of food and cooking. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:124602. [PMID: 26534781 DOI: 10.1088/0034-4885/78/12/124602] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This review discusses the (soft matter) physics of food. Although food is generally not considered as a typical model system for fundamental (soft matter) physics, a number of basic principles can be found in the interplay between the basic components of foods, water, oil/fat, proteins and carbohydrates. The review starts with the introduction and behavior of food-relevant molecules and discusses food-relevant properties and applications from their fundamental (multiscale) behavior. Typical food aspects from 'hard matter systems', such as chocolates or crystalline fats, to 'soft matter' in emulsions, dough, pasta and meat are covered and can be explained on a molecular basis. An important conclusion is the point that the macroscopic properties and the perception are defined by the molecular interplay on all length and time scales.
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Affiliation(s)
- Thomas A Vilgis
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55129 Mainz, Germany
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3
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Regulation of crystalline morphologies and mechanical properties of olefin multiblock copolymers by blending polymer with similar architecture of constituent blocks. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.07.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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4
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Hugouvieux V, Kolb M. Multiblock copolymer solutions in contact with a surface: self-assembly, adsorption, and percolation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12400-12410. [PMID: 25285477 DOI: 10.1021/la502945k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Amphiphilic copolymers are often used as compatibilizing or stabilizing agents, either in solution or at surfaces. In the special case of multiblock copolymers the connectivity of the blocks combines with the antagonistic behavior of the different types of blocks. Here we report on the behavior of solutions of amphiphilic multiblock copolymers with a large number of blocks and a low fraction of solvophobic monomers in contact with an attractive surface. Using lattice Monte Carlo simulations, the influence on the structures of the solvent quality and the type of surface from noninteracting to strongly attractive to the solvophobic monomers can be assessed. In the presence of a surface bulk micelles are formed that are not different in size and shape from the micelles observed in the absence of a surface. When increasing the surface attraction, solvophobic monomers tend to adsorb either as isolated blocks or forming surface micelles. Evidence is given of a surface concentration threshold above which surface micelles can form due to microphase separation. These surface micelles are in equilibrium with bulk micelles, some of which are connected to the surface through a path of either hydrophobic and/or hydrophilic blocks or hydrophobic cross-links, or both. The size distributions of bulk and connected micelles are similar. With increasing surface concentration surface micelles get organized due to the steric repulsion between core-shell surface micelles. Moreover, these organized surface micelles percolate. The connected micelles form a concentrated layer parallel to the attractive surface. In addition, these systems are governed by two very different time scales: The fast one leads to micellar self-assembly in the bulk and at the surface while the slow one prevents the system from reaching equilibrium in the course of the simulations and corresponds to the transfer of copolymers from the bulk to the attractive surface.
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Angelova N, Yordanov G. Nanoparticles of poly(styrene-co-maleic acid) as colloidal carriers for the anticancer drug epirubicin. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2014.03.106] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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6
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Hao W, Porter D, Wang X, Shao Z. Silk fibroin-mediated biomineralization of calcium carbonate at the air/water interface. CrystEngComm 2014. [DOI: 10.1039/c4ce01092b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The morphology and polymorphs of CaCO3 that crystallized at the air/water interface depend on the assembly of silk fibroin therein.
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Affiliation(s)
- Wei Hao
- State Key Laboratory of Molecular Engineering of Polymers
- Advanced Materials Laboratory
- Department of Macromolecular Science
- Fudan University
- Shanghai, People's Republic of China
| | - David Porter
- Department of Zoology
- University of Oxford
- Oxford OX1 3PS, UK
| | - Xianting Wang
- State Key Laboratory of Molecular Engineering of Polymers
- Advanced Materials Laboratory
- Department of Macromolecular Science
- Fudan University
- Shanghai, People's Republic of China
| | - Zhengzhong Shao
- State Key Laboratory of Molecular Engineering of Polymers
- Advanced Materials Laboratory
- Department of Macromolecular Science
- Fudan University
- Shanghai, People's Republic of China
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7
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Pafiti KS, Patrickios CS, Abetz C, Abetz V. High-molecular-weight symmetrical multiblock copolymers: Synthesis by RAFT polymerization and characterization. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pola.26936] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Kyriaki S. Pafiti
- Department of Chemistry; University of Cyprus; P.O. Box 20537, 1678 Nicosia Cyprus
| | - Costas S. Patrickios
- Department of Chemistry; University of Cyprus; P.O. Box 20537, 1678 Nicosia Cyprus
| | - Clarissa Abetz
- Institute of Polymer Research, Helmholtz-Zentrum Geesthacht; Max-Planck-Str. 1 21502 Geesthacht Germany
| | - Volker Abetz
- Institute of Polymer Research, Helmholtz-Zentrum Geesthacht; Max-Planck-Str. 1 21502 Geesthacht Germany
- Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
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8
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Zhao W, Wang Y, Liu X, Chen X, Cui D, Chen EYX. Protic compound mediated living cross-chain-transfer polymerization of rac-lactide: synthesis of isotactic (crystalline)-heterotactic (amorphous) stereomultiblock polylactide. Chem Commun (Camb) 2012; 48:6375. [PMID: 22618274 DOI: 10.1039/c2cc32680a] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
A highly efficient strategy for one-pot synthesis of programmable, crystalline-amorphous stereomultiblock PLA from rac-lactide.
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Affiliation(s)
- Wei Zhao
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin street, Changchun 130022, China.
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Ramírez P, Stocco A, Muñoz J, Miller R. Interfacial rheology and conformations of triblock copolymers adsorbed onto the water-oil interface. J Colloid Interface Sci 2012; 378:135-43. [PMID: 22575779 DOI: 10.1016/j.jcis.2012.04.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 04/11/2012] [Accepted: 04/12/2012] [Indexed: 01/03/2023]
Abstract
The conformation and the dilatational properties of three non-ionic triblock PEO-PPO-PEO (where PEO is polyethyleneoxide and PPO is polypropyleneoxide) copolymers of different hydrophobicity and molecular weight were investigated at the water-hexane interface. The interfacial behavior of the copolymers was studied by combining dilatational rheology using the oscillating drop method and ellipsometry. From the dilatational rheology measurements the limiting elasticity values, E(0), of the Pluronics as function of surface pressure, Π, and adsorption time were obtained, i.e. E(0)(t) and E(0)(Π). Here, it is shown that E(0)(t) depends on the number of PEO units and on the bulk concentration, showing maximum and minimum surface elasticity values which indicate conformational changes in the interfacial layer. Furthermore, in the framework of the polymer scaling law theory, conformational transitions were discussed in E(0) vs. Π plots. In a dilute regime (Π<14 mN m(-1)) at the water-hexane interface, E(0)=2Π fits well all the data, which indicates a two-dimensional "stretched chain" conformation. Increasing Π, two other interfacial transitions could take place. The different behavior of Pluronic copolymers could be also described by the local minima of E(0), which depends on the hydrophobicity of the copolymers. Conformational transitions observed by interfacial rheology were compared to ellipsometric data. Experimental results were discussed and explained on the basis of two- and three-dimensional copolymer structure taking into account that PPO chains could be partially immersed in hexane and water.
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Affiliation(s)
- Pablo Ramírez
- Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, Sevilla, Spain.
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10
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Barik S, Bletzacker T, Skene WG. π-Conjugated Fluorescent Azomethine Copolymers: Opto-Electronic, Halochromic, and Doping Properties. Macromolecules 2012. [DOI: 10.1021/ma2024304] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Satyananda Barik
- Laboratoire
de caractérisation photophysique
des matériaux conjugués, Département de Chimie,
Pavillon JA Bombardier, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C
3J7, Canada
| | - Thomas Bletzacker
- Laboratoire
de caractérisation photophysique
des matériaux conjugués, Département de Chimie,
Pavillon JA Bombardier, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C
3J7, Canada
| | - W. G. Skene
- Laboratoire
de caractérisation photophysique
des matériaux conjugués, Département de Chimie,
Pavillon JA Bombardier, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C
3J7, Canada
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11
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Dynamic interfacial tension of triblock copolymers solutions at the water–hexane interface. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.04.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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12
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Multiblock Copolymers of Styrene and Butyl Acrylate via Polytrithiocarbonate-Mediated RAFT Polymerization. Polymers (Basel) 2011. [DOI: 10.3390/polym3020719] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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13
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Ebeling B, Eggers M, Vana P. Ideal Molecular Weight Distributions of Multiblock Copolymers Prepared via RAFT Polymerization. Macromolecules 2010. [DOI: 10.1021/ma1020424] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bastian Ebeling
- Institut für Physikalische Chemie, Georg-August-Universität Göttingen, Tammannstr. 6, D-37077 Göttingen, Germany
| | - Martin Eggers
- Fakultät für Informatik, Technische Universität München, Barer Str. 21, D-80333 München, Germany
| | - Philipp Vana
- Institut für Physikalische Chemie, Georg-August-Universität Göttingen, Tammannstr. 6, D-37077 Göttingen, Germany
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14
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Adsorption properties of oligo(fluorooxetane)-b-poly(ethylene oxide)-b-oligo(fluorooxetane) triblock copolymers at the air–water interface: Comparison of hydroxyl and acetate end groups. J Colloid Interface Sci 2009; 336:40-5. [DOI: 10.1016/j.jcis.2009.03.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 03/25/2009] [Accepted: 03/25/2009] [Indexed: 11/19/2022]
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15
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Kłos JS, Sommer JU. Adsorption of random copolymers by a selective layer: Monte Carlo studies. J Chem Phys 2008; 128:164908. [DOI: 10.1063/1.2894870] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Ertekin A, Kausch CM, Kim Y, Thomas RR. Synthesis, characterization, adsorption, and interfacial rheological properties of four-arm anionic fluorosurfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:2412-2420. [PMID: 18266395 DOI: 10.1021/la7031175] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Four-arm oligo(fluorooxetane) tetraols containing -CF3 and -C2F5 groups were prepared in reasonable yields by cationic, ring-opening polymerization of fluorinated oxetane monomers using a tetrafunctional, alkoxylated polyol as initiator and BF3.THF as catalyst. The tetraols were then converted to ammonium sulfate salts using oleum followed by neutralization with ammonium hydroxide in excellent yields. The four-arm oligo(fluorooxetane) sulfates (1=-CF3, 2=-C2F5) have an architecture characterized by a hydrophobic core of oligo(fluorooxetane) arms with a hydrophilic sulfate shell and initiator. The four-arm anionic oligo(fluorooxetane)s are surface active with critical micelle concentration values approximately 4.2x10(-6) and 2.4x10(-6) mol/L for 1 and 2, respectively. Surface tension isotherms in pH 8 buffered solution were measured and data fitted parametrically to the Davies surface tension isotherm equation. Molecular areas at saturation were estimated to be approximately 89 and approximately 85 A2 with DeltaGads=-12.7 and -13.2 kcal/mol for 1 and 2, respectively. The results are compared to two-arm, bolaamphiphilic analogues of 1 and 2 and a small molecule, long perfluoroalkyl-chain (-C8F17), anionic fluorosurfactant (Kausch, C. M.; Kim, Y.; Russell, V. M.; Medsker, R. E.; Thomas, R. R. Langmuir 2003, 19, 7182). Dynamic surface tension data for 1 and 2 were analyzed using the Ward-Tordai mass transport equation to yield concentration-dependent diffusion coefficients. In the concentration range approximately 10(-6) mol/L, diffusion coefficients were estimated to be approximately 1-3x10(-5) cm2/s. Dilational interfacial rheological parameters for 1 and 2 were measured. Values of |E| and E' were found to be larger than those of the two-arm analogues of the same perfluoroalkyl chain length while E' 'and phi were found to be smaller. The magnitude of these values reflects the difference in adsorption strength and mass transport and/or relaxation between the two different architectures.
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Affiliation(s)
- Ayça Ertekin
- Department of Polymer Engineering, Polymer Engineering Academic Center, The University of Akron, Akron, Ohio 44325-0301, USA
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17
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Kłos J, Sommer JU. Random copolymers at a selective interface: Saturation effects. J Chem Phys 2007; 127:174901. [DOI: 10.1063/1.2794330] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Noskov BA. Dynamic elasticity of triblock copolymer of poly(ethylene oxide) and poly(propylene oxide) on a water surface. COLLOID JOURNAL 2006. [DOI: 10.1134/s1061933x06050103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Noskov BA, Lin SY, Loglio G, Rubio RG, Miller R. Dilational viscoelasticity of PEO-PPO-PEO triblock copolymer films at the air-water interface in the range of high surface pressures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:2647-52. [PMID: 16519465 DOI: 10.1021/la052662d] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The dynamic dilational elasticity of adsorbed and spread films of PEO-PPO-PEO triblock copolymers at the air-water interface was measured as a function of surface pressure, surface age, and frequency. At low surface pressures (<10 mN/m), the surface viscoelasticity is identical to that of PEO homopolymer films. The results at higher surface pressures can be explained by the desorption of PPO segments from the interface and then mixing with PEO segments in water. Unlike some recent results, the spread and adsorbed films are not identical. Spread films exhibit a maximum real part of the dynamic surface elasticity of about 20 mN/m and probably begin to dissolve in water at surface pressures above 19 mN/m. However, the surface elasticity of the adsorbed films decreases beyond the maximum, indicating the formation of a loose surface structure.
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Affiliation(s)
- B A Noskov
- St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia
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20
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Corsi A, Milchev A, Rostiashvili VG, Vilgis TA. Kinetics of Copolymer Localization at a Selective Liquid−Liquid Interface. Macromolecules 2006. [DOI: 10.1021/ma051853k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Corsi
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Institute for Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - A. Milchev
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Institute for Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - V. G. Rostiashvili
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Institute for Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - T. A. Vilgis
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Institute for Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Corsi A, Milchev A, Rostiashvili VG, Vilgis TA. Localization of a multiblock copolymer at a selective interface: Scaling predictions and Monte Carlo verification. J Chem Phys 2005; 122:094907. [PMID: 15836181 DOI: 10.1063/1.1854133] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the localization of a hydrophobic-polar regular copolymer at a selective solvent-solvent interface with emphasis on the impact of block length M on the copolymer behavior. The considerations are based on simple scaling arguments and use the mapping of the problem onto a homopolymer adsorption problem. The resulting scaling relations treat the gyration radius of the copolymer chain perpendicular and parallel to the interface in terms of chain length N and block size M, as well as the selectivity parameter chi. The scaling relations differ for the case of weak and strong localization. In the strong localization limit a scaling relation for the lateral diffusion coefficient D( parallel) is also derived. We implement a dynamic off-lattice Monte Carlo model to verify these scaling predictions. For chain lengths in a wide range (32</=N</=512) we find good agreement with the scaling predictions.
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Affiliation(s)
- Andrea Corsi
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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23
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Hambardzumyan A, Aguié-Béghin V, Daoud M, Douillard R. beta-casein and symmetrical triblock copolymer (PEO-PPO-PEO and PPO-PEO-PPO) surface properties at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:756-763. [PMID: 15773102 DOI: 10.1021/la030294c] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A comparison of beta-casein and symmetrical triblock copolymer (PEO-PPO-PEO and PPO-PEO-PPO) adsorption layer properties at the air-water interface has been carried out by bubble tensiometry and ellipsometry. It has been verified that the equation of state parameters (pi approximately gamma(y)) obtained from surface pressure (pi) and ellipticity in Brewster conditions (rhoB), which is proportional to the surface concentration (gamma) data, are the same as those obtained from dilational modulus epsilon and pi data. These two consistent approaches give further support to the theoretical model of block copolymers which has been previously developed for protein adsorption at fluid interfaces. It is shown that the interfacial behavior of the copolymer adsorption layer changes strongly as a function of the length of the hydrophilic and hydrophobic block sequences. The theoretical model may be used for the interpretation of the adsorption properties of the synthetic copolymers only when the size of the blocks is large enough. In the case of block copolymers, the coil is in a self-avoiding walk conformation (y = 3) whatever the temperature, while in the case of beta-casein, the polypeptide chain is partly collapsed at room temperature due to thermolabile noncovalent bonds. At the end of the first semidilute regime, there is clear evidence for a crossover toward a second semidilute regime for synthetic copolymers as well as for beta-casein but it is presently only partially characterized.
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Affiliation(s)
- Arayik Hambardzumyan
- INRA /URCA, UMR FARE, Centre de Recherche en Environnement et Agronomie, 2 Espl. Roland Garros, BP 224, 51686 Reims, Cedex 2, France
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24
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Douillard R, Daoud M, Aguié-Béghin V. Polymer thermodynamics of adsorbed protein layers. Curr Opin Colloid Interface Sci 2003. [DOI: 10.1016/s1359-0294(03)00097-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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25
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Aguié-Béghin V, Leclerc E, Daoud M, Douillard R. Asymmetric Multiblock Copolymers at the Gas-Liquid Interface: Phase Diagram and Surface Pressure. J Colloid Interface Sci 1999; 214:143-155. [PMID: 10339355 DOI: 10.1006/jcis.1999.6144] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A theoretical model of copolymers made of N blocks is studied at the air-water interface. Each block is made of a sequence A of ZA hydrophobic and of a sequence B of ZB hydrophilic monomers. The A and B sequences cannot cross the interface. The conformation of an adsorbed polymer is determined as a random walk of N elements whose size is the Flory radius of a single sequence. The structure of the interfacial layer is determined as a function of alpha = ZA/ZB and of the surface concentration using scaling law arguments. Only three different regions are found in the phase diagram to describe the change of surface regime as a function of the total surface concentration. The energy of flower-like micelles of polymers is calculated and compared with the energy of adsorbed macromolecules in order to determine the surface concentration at saturation. The surface pressure is also calculated as a function of the surface concentration in the three different regions of the phase diagram. It is found that these surface pressure isotherms are not affected by the solvent quality except when the properties of the interfacial layer are dominated by a purely two-dimensional behavior (semidiluted regime of the whole polymer or of the A sequences on the air side of the interface). Finally the properties of this model are compared with experimental data obtained with protein adsorbed layers and encouraging agreement is found although proteins are much more complicated polymers than this crude model. Copyright 1999 Academic Press.
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Affiliation(s)
- V Aguié-Béghin
- Institut National de la Recherche Agronomique, Centre de Recherche Agronomique, 2 Esplanade Roland Garros, Reims Cedex 2, 51686, France
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Puff N, Cagna A, Aguié-Béghin V, Douillard R. Effect of Ethanol on the Structure and Properties of beta-Casein Adsorption Layers at the Air/Buffer Interface. J Colloid Interface Sci 1998; 208:405-414. [PMID: 9845684 DOI: 10.1006/jcis.1998.5846] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The adsorption of beta-casein at the air-solution interface has been monitored in equilibrium conditions by neutron reflectivity. It was observed that for a bulk concentration of 100 mg/L, the amount of protein adsorbed per unit surface increases from 2.8 to 4.4 mg/m2 when the ethanol concentration in the bulk changes from 0 to 20% (v/v). Surface pressure measurements on aqueous solutions indicate that the surface pressure is higher when both protein and alcohol are added than when a single substance is in the solution. The addition of protein has an effect when the alcohol concentration is less than 20%. These results are consistent with the occurrence at the interface of a protein network leaving a surface fraction available for ethanol. A thermodynamic model has been developed using scaling law arguments to model the surface pressure and dilational modulus measurements. It introduces an exponent which is characteristic of the solvent "quality" and of the structure of the interfacial layer. The results are interpreted as showing that ethanol modifies the solvent properties, the interactions between the protein and the solvent, and the structure of the adsorption layer. The main transition seems to occurr at 6% ethanol. Copyright 1998 Academic Press.
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Affiliation(s)
- N Puff
- Équipe de Biochimie des Macromolécules Végétales, INRA, Centre de Recherche Agronomique, 2 Esplanade Roland Garros, Reims Cedex 2, 51686, France
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