Effect of Composition Distribution on Microphase-Separated Structure from Diblock Copolymers

Matsushita, Yushu; Noro, Atsushi; Iinuma, M.; Suzuki, Jirô; Ohtani, Hajime; Takano, Atsushi

doi:10.1021/ma0301496

Cited by 102 publications

(151 citation statements)

References 19 publications

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“…A flurry of theoretical [25][26][27][28][29][30][31][32][33][34] and a͒ Authors to whom correspondence should be addressed: Electronic addresses: hillmyer@umn.edu and bates@cems.umn.edu. experimental 11,27,[35][36][37][38][39][40][41][42][43] studies of polydispersity effects in AB block copolymers followed Bendejacq et al's report. This topic recently has been reviewed, 44 and only a brief summary is provided below.…”

Section: Introductionmentioning

confidence: 91%

“…The reduction in elastic free energy is also accompanied by an increase in the height of end-grafted polymer brushes 17 and an increase in the domain period in the melt. [27][28][29]31,33,[35][36][37]43 Furthermore, the distribution of chain lengths present in polydisperse materials may stabilize additional ordered mesostructures. Listak et al 42 recently reported that polydispersity stabilized a hexagonally perforated lamellar mesostructure in poly͑styrene-b-methyl acrylate͒ diblock copolymers; this structure is considered metastable in nearly monodisperse materials.…”

Section: Introductionmentioning

confidence: 99%

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Polydispersity effects in poly(isoprene-b-styrene-b-ethylene oxide) triblock terpolymers

Meuler

Ellison

Qin

et al. 2009

The Journal of Chemical Physics

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Four hydroxyl-terminated poly͑isoprene-b-styrene͒ diblock copolymers with comparable molecular weights and compositions ͑equivalent volume fractions of polyisoprene and polystyrene͒ but different polystyrene block polydispersity indices ͑M w / M n = 1.06, 1.16, 1.31, 1.44͒ were synthesized by anionic polymerization using either sec-butyllithium or the functional organolithium 3-triisopropylsilyloxy-1-propyllithium. Poly͑ethylene oxide͒ ͑PEO͒ blocks were grown from the end of each of these parent diblocks to yield four series of poly͑isoprene-b-styrene-b-ethylene oxide͒ ͑ISO͒ triblock terpolymers that were used to interrogate the effects of varying the polydispersity of the middle bridged polystyrene block. In addition to the neat triblock samples, 13 multicomponent blends were prepared at four different compositions from the ISO materials containing a polystyrene segment with M w / M n = 1.06; these blends were used to probe the effects of increasing the polydispersity of the terminal PEO block. The melt-phase behavior of all samples was characterized using small-angle X-ray scattering and dynamic mechanical spectroscopy. Numerous polydispersity-driven morphological transitions are reported, including transitions from lamellae to core-shell gyroid, from core-shell gyroid to hexagonally packed cylinders, and from network morphologies ͓either O 70 ͑the orthorhombic Fddd network͒ or core-shell gyroid͔ to lamellae. Domain periodicities and order-disorder transition temperatures also vary with block polydispersities. Self-consistent field theory calculations were performed to supplement the experimental investigations and help elucidate the molecular factors underlying the polydispersity effects. The consequences of varying the polydispersity of the terminal PEO block are comparable to the polydispersity effects previously reported in AB diblock copolymers. Namely, domain periodicities increase with increasing polydispersity and domain interfaces tend to curve toward polydisperse blocks. The changes in phase behavior that are associated with variations in the polydispersity of the middle bridged polystyrene block, however, are not analogous to those reported in AB diblock copolymers, as increases in this middle block polydispersity are not always accompanied by ͑i͒ increased domain periodicities and ͑ii͒ a tendency for domain interfaces to curve toward the polydisperse domain. These results highlight the utility of polydispersity as a tool to tune the phase behavior of ABC block terpolymers.

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Polydispersity effects in poly(isoprene-b-styrene-b-ethylene oxide) triblock terpolymers

Meuler

Ellison

Qin

et al. 2009

The Journal of Chemical Physics

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“…Although long time the idea was set that ordered microphases in block copolymers can be achieved only by a narrow dispersity, [68] some studies have demonstrated their self-assembly into well-ordered structures even presenting a broader molecular weight distribution (MWD). [69][70][71][72][73] Our starting materials for the blends exhibit, with values of 1.16 and 1.19 for neat SIM and ISM, by themselves relatively broad MWDs and as both terpolymers have unequal molecular weights the combination in a blend provides both a polydispersity in molecular weight and composition. The repulsive segmental interactions between the copolymer blocks is the driving force for microphase separation and leads them to stretch in order to adopt a minimum of interfacial contact area.…”

Section: Resultsmentioning

confidence: 95%

Four‐Phase Morphologies in Blends of ABC and BAC Triblock Terpolymers

Haenelt

Abetz

2017

Macro Chemistry & Physics

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considerably more complex compared to diblock copolymers due to an increased number of variables. Thus, the morphology of linear ABC triblock terpolymers is controlled mainly by three interaction parameters (χ AB , χ AC , χ BC ,) and two independent volume fractions (f A , f B , f C = 1 -f A -f B ), as well as the block sequence. Among the morphologies are lamellae, lamellae with spheres or cylinders, knitting pattern, spheres on sphere, alternating and core-shell double gyroids, cylinder in cylinder, undulated/perforated cylinder in cylinder, cylinder at cylinder, spheres on cylinder, helices on cylinder. [12][13][14][15][16][17][18] The helices on cylinder represents a special case in between these morphologies. On the one hand, it is rare because it can be achieved only in a rather narrow composition window, but what is even more peculiar, it is the self-assembly of a nonchiral block copolymer into a chiral structure. [19] In order to develop functional materials with special electrical, optical, or magnetic properties, multiblock copolymers are promising, because of their capability to self-assemble into complex ordered morphologies, with symmetries like crystalline structures known from low molecular weight inorganic salts. [20] Lee et al. [21,22] were the first to identify a Frank-Kasper σ phase, which is a large tetragonal unit cell with P4 2 /mnm symmetry and 30 spheres, [23,24] in linear block copolymers. From then on numerous studies about novel sphere-forming morphologies in AB diblock [25][26][27] copolymers and ABAC tetrablock terpolymers [28] have been published. Especially linear ABAC tetrablock terpolymers are promising for the investigation of new structures. [29] Chanpuriya et al. [30] have presented nine different spherical phases for tetrablock terpolymers.Controlling the morphology for a given block copolymer by changing the volume fractions of the corresponding blocks implies the synthesis of one block copolymer for each morphology. There are other, more readily available methods to achieve different morphologies starting from one block copolymer. One method implicates chemical postmodification, like complexation or hydrogenation. Bronstein et al. [31] have modified the polybutadiene block (PB) of a polystyreneblock-polybutadiene-block-poly(methyl methacrylate) (SBM) triblock terpolymer by complexation with transition metal complexes, like Fe-complex and Pd-complex. They were able to observe a change from a lamellar morphology before modification to a cylindrical or gyroid morphology after the Blends It is investigated how binary blends of two asymmetric triblock terpolymers with the same type of monomers but different block sequences (ABC, BAC) and different block lengths lead to three new ABAC tetrablock terpolymer like morphologies. This study ascribes the formation of four microphases to a parallel chain orientation during the blend process. Because of the resultant spatial superposition, the B-blocks of both block copolymers can mix into each other as well as both C-blocks, whereas bot...

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“…The previous morphological observation for polydisperse block copolymers in composition and molecular weight clarified that lamellar domain spacing increases linearly with increasing the polydispersity in molecular weight or composition. [25][26][27] However, these results suggested only speculation on spatial distribution of the component block chains in microdomains. Thus, the segmental distribution of the component chains in block copolymer blends was directly examined by neutron reflectometry.…”

Section: Localization Of Component Chains In a Block Copolymer Blend mentioning

confidence: 88%

“…The evaluated segmental distribution in the block copolymer blend supported the previous morphological observations well. [25][26][27] Interdiffusion Behavior of a Cyclic Polystyrene Compared with a Linear Homologue A cyclic polymer has attracted much attention from the aspects of polymer physics due to its unique feature in molecular architecture with no chain ends. The existence of chain ends is essential for polymer dynamics such as diffusion and relaxation of a linear polymer chain in melt in the context of reptation theories.…”

Section: Localization Of Component Chains In a Block Copolymer Blend mentioning

confidence: 99%

Neutron Reflectometry on Interfacial Structures of the Thin Films of Polymer and Lipid

Torikai

Yamada

Noro

et al. 2007

Polym J

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ABSTRACT:Neutron reflectometry is a very powerful and essential technique for the studies on material interfaces due to its high spatial resolution, $a few tenths of nm, along the depth direction. The use of neutron as a probe is a big advantage for structural analysis on soft-materials, since the scattering contrast can be highly enhanced in hydrogenous materials such as polymers, surfactants, lipids, proteins, etc., without big changes in their physical and chemical properties by substituting all or part of the hydrogen atoms in the molecules with deuterium (a deuterium labeling method). Furthermore, the neutron reflectometry can explore deeply-buried interfaces such as solid/liquid interfaces in a non-destructive way, and make in situ measurements combined with various sample environments due to its high transmission to the materials. In this article, the neutron reflectometry is reviewed from the standpoint of researches on interfacial structures of the thin films of polymer and lipid, and its future prospects at a high-intensity pulsed-neutron source are presented. [doi:10.1295/polymj.PJ2007113] KEY WORDS Neutron Reflectometry / High Depth Resolution / Soft-material / Deuterium Labeling / Non-destructive Exploration / Deeply-buried Interface / In situ Measurement / At interfaces, materials often exhibit different structures or physical properties from in bulk because they interact directly with different materials or phases in a very narrow space. So far many interesting phenomena relevant to interfaces have been reported, e.g., lower surface glass transition temperature, de-wetting, surface segregation, etc., in the research field of softmaterials.1,2 Also, material interfaces contribute largely to many practical phenomena known as coating, painting, adhesion, lubrication, etc. In addition, the recent development of nano-technology makes the size of practical devices smaller, so that interfaces occupy the larger proportion of space in the devices, and then play an important role in the device performance. Therefore, strong demands to clarify the structures and physical properties of materials at interfaces have been rapidly grown.However, in reality it is generally difficult to observe detailed interfacial structure, since the interfacial region is very narrow and has considerably small volume in materials. The material interfaces are not always exposed to air surface, but are deeply buried in materials. Neutron reflectometry is a very powerful and indispensable technique to the studies on material interfaces because of its high spatial resolution, $a few tenths of nm, along the depth direction. Here, the neutron reflectometry is reviewed from the standpoint of soft-material researches by highlighting experimental examples on the thin films of polymer and lipid systems, and its future prospects at a highintensity pulsed-neutron source are presented. NEUTRON REFLECTOMETRYNeutron has unique properties as a probe for structural analysis of materials, compared with electromagnetic waves such as light or X-ray....

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Effect of Composition Distribution on Microphase-Separated Structure from Diblock Copolymers

Cited by 102 publications

References 19 publications

Polydispersity effects in poly(isoprene-b-styrene-b-ethylene oxide) triblock terpolymers

Polydispersity effects in poly(isoprene-b-styrene-b-ethylene oxide) triblock terpolymers

Four‐Phase Morphologies in Blends of ABC and BAC Triblock Terpolymers

Neutron Reflectometry on Interfacial Structures of the Thin Films of Polymer and Lipid

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