Dilute solutions and phase behavior of polydisperse A-b-(A-co-B) diblock copolymers

Gromadzki, Daniel; Lokaj, J.; Šlouf, Miroslav; Štěpánek, Petr

doi:10.1016/j.polymer.2009.03.022

Cited by 21 publications

(11 citation statements)

References 54 publications

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“…73 Experimental observation of FCC spheres has been reported in a higher dispersity diblock copolymer following melt processing. 74 The triblock copolymer employed in our study was synthesized through RAFT polymerization and had a trimodal molecular weight distribution ( Figure S1). As discussed previously, 75 the lower molecular weight mode to the right of the primary peak is attributed to the presence of poly(lauryl-costearyl acrylate) precursor that was not chain extended, and the higher molecular weight mode to the left of the primary peak is attributed to the presence of chain branching.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Close-Packed Spherical Morphology in an ABA Triblock Copolymer Aligned with Large-Amplitude Oscillatory Shear

et al. 2016

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A microphase-separated poly(styrene-b-(lauryl-co-stearyl acrylate)-bstyrene) (SAS) triblock copolymer exhibiting a disordered spherical microstructure with randomly oriented grains was aligned through the application of large-amplitude oscillatory shear (LAOS) at a temperature below the order−disorder transition temperature of the triblock copolymer, yet above the glass transition temperature of the polystyrene spherical domains. The thermoplastic elastomeric behavior of the SAS triblock copolymer provided a convenient means to observe the aligned morphology. Following application of LAOS, the specimen was quenched to room temperature (below the glass transition temperature of polystyrene), and small-angle X-ray scattering data were obtained in the three principal shear directions: shear gradient, velocity, and vorticity directions. The analysis revealed that the SAS triblock copolymer formed coexisting face-centered cubic and hexagonally close-packed spherical microstructures. The presence of a close-packed microstructure is in stark contrast to an extensive body of literature on sphere-forming bulk block copolymers that favor body-centered cubic systems under quiescent conditions and under shear. The aligned microstructure observed in this bulk block copolymer was reminiscent of that observed in various spherical soft material systems such as colloidal spheres, sphere-forming block copolymer solutions, and star polymer solutions. The highly unanticipated observation of close-packed spherical microstructures in a neat block copolymer under shear is hypothesized to originate from the dispersity of the block copolymer. ■ INTRODUCTIONBlock copolymers composed of two incompatible polymers spontaneously self-assemble into various equilibrium nanoscale phases, including lamellae, hexagonally close-packed cylinders, body-centered cubic spheres, and a bicontinuous gyroid morphology. 1,2 These materials have many potential applications, such as thermoplastic elastomers, membranes for batteries, fuel cells and water purification, and solution-based assemblies for encapsulation of hydrophobic guest molecules and drug delivery. 1,2 Block copolymer morphologies formed spontaneously in the melt are randomly oriented, lacking longrange order, and the materials are macroscopically isotropic. The application of external forces, such as shear, 3 electric fields, 4,5 magnetic fields, 6 or preferential surfaces, 7 can lead to alignment of the block copolymer into anisotropic structures and induce long-range ordering. Control of structural orientation is key to manipulating the properties of these materials for desired applications.The application of shear, whether steady shear or largeamplitude oscillatory shear (LAOS), is a common approach for the alignment of bulk block copolymers. Extensive studies have focused on alignment of lamellae-forming systems through steady shear or LAOS. 3,8−16 Three possible alignment orientations have been identified as parallel, perpendicular, and transverse with respect to the shear flow direction....

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Section: ■ Results and Discussionmentioning

confidence: 99%

Close-Packed Spherical Morphology in an ABA Triblock Copolymer Aligned with Large-Amplitude Oscillatory Shear

et al. 2016

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“…While not all of the studies were done for the purpose of barrier materials, these studies suggest opportunities to use the barrier properties of AN in the form of a copolymer, provided sufficient AN is incorporated. Besides statistical copolymerization, block copolymers containing AN have been made, which provides another route to incorporating PAN's barrier properties . The ability to polymerize AN by radical polymerization techniques, particularly by reversible activation/de‐activation polymerization (RADP) techniques such as reversible addition fragmentation transfer (RAFT), atom transfer radical polymerization (ATRP), and nitroxide mediated polymerization (NMP), makes the subsequent polymer interesting for barrier materials as the microstructure can be tuned in many possible ways due to the possibility of forming block copolymers.…”

Section: Introductionmentioning

confidence: 99%

“…Besides statistical copolymerization, block copolymers containing AN have been made, which provides another route to incorporating PAN's barrier properties. [13][14][15][16][17][18][19][20][21][22][23][24][25] The ability to polymerize AN by radical polymerization techniques, particularly by reversible activation/ de-activation polymerization (RADP) techniques such as reversible addition fragmentation transfer (RAFT), atom transfer radical polymerization (ATRP), and nitroxide mediated polymerization (NMP), makes the subsequent polymer interesting for barrier materials as the microstructure can be tuned in many possible ways due to the possibility of forming block copolymers. Additionally, properties can be further combined into the AN containing (co)polymers by blending with other polymers.…”

Section: Introductionmentioning

confidence: 99%

Reactive compatibilization of poly(styrene‐ran‐acrylonitrile)/poly(ethylene) blends through the acid–epoxy reaction

Gill

Hong

Gromadzki

et al. 2016

J of Applied Polymer Sci

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Two families of acid functional styrene/acrylonitrile copolymers (SAN) for application as dispersed phase barrier materials in poly(ethylene) (PE) were studied. One type is SAN made by nitroxide mediated polymerization (NMP), which was subsequently chain extended with a styrene/tert‐butyl acrylate (S/tBA) mixture to provide a block copolymer (number average molecular weight Mn = 36.6 kg mol−1 and dispersity Đ = 1.34, after which the tert‐butyl protecting groups were converted to acid groups (SAN‐b‐S/AA). The other acid functional SAN is made by conventional radical terpolymerization (SAN‐AA). SAN‐AA and SAN‐b‐S/AA were each melt blended with PE grafted with epoxy functional glycidyl methacrylate (PE‐GMA) at 160 °C in a twin screw extruder (70:30 wt % PE‐GMA:SAN co/terpolymer). The non‐reactive PE‐g‐GMA/SAN blend had a volume to surface area diameter 〈D〉vs = 3.0 μm while the reactive blends (via epoxy/acid coupling) (PE‐GMA/SAN‐b‐SAA and PE‐GMA/SAN‐AA) had 〈D〉vs = 1.7 μm and 1.1 μm, respectively. After thermal annealing, the non‐reactive blend coarsened dramatically while the reactive blends showed little signs of coarsening, suggesting that the acid/epoxy coupling was effective for morphological stability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44178.

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“…Block copolymers have unique microphase separation, which make them have broad application including dispersants, compatibilizers, surfactants, emulsifiers, foam stabilizers and templates for functional materials [1][2][3][4][5]. Besides the common properties of block copolymers, cross-linkable block copolymers presented more advantages.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and properties of cross-linkable block copolymer end-capped with 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate

Sun

Liu

2011

J Polym Res

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A series of novel cross-linkable copolymers 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate-poly (isobutyl methacrylate)-b-poly [3-(trimethoxysilyl)propyl methacrylate] (HFMA-PIBMA-b-PTMSPMA) were synthesized via atom transfer radical polymerization (ATRP). The synthesis and structure of the polymers were characterized by gel permeation chromatography (GPC), Fourier transform infrartd (FTIR) and 1 H nuclear magnetic resonance (NMR). The properties of HFMA-PIBMA-b-PTMSPMA and the corresponding copolymers end-capped with nonfluorinated acrylate were comparatively studied by contact angle, transmission electron micrograph (TEM), and dynamic light scattering (DLS) measurement. The results indicated that the surface properties and self-assembly behaviors of HFMA-PIBMA-b-PTMSPMA were changed greatly by the introducing of only one fluorinated acrylate. Finally, the transparent solid materials with a slightly blue color were obtained based on the cross-linked behaviors of HFMA-PIBMA-b-PTMSPMA and fracture surfaces of the materials were exhibited by scanning electron microscopy (SEM).

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Dilute solutions and phase behavior of polydisperse A-b-(A-co-B) diblock copolymers

Cited by 21 publications

References 54 publications

Close-Packed Spherical Morphology in an ABA Triblock Copolymer Aligned with Large-Amplitude Oscillatory Shear

Close-Packed Spherical Morphology in an ABA Triblock Copolymer Aligned with Large-Amplitude Oscillatory Shear

Reactive compatibilization of poly(styrene‐ran‐acrylonitrile)/poly(ethylene) blends through the acid–epoxy reaction

Synthesis and properties of cross-linkable block copolymer end-capped with 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate

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