A Phase Diagram for the Binary Blends of Nearly Symmetric Diblock Copolymers. 1. Parameter Space of Molecular Weight Ratio and Blend Composition

Yamaguchi, Daisuke; Hashimoto, Takeji

doi:10.1021/ma0021489

Cited by 71 publications

(141 citation statements)

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“…Studies show that blends of two AB diblock copolymers exhibit a much richer phase behavior than each neat constituent diblock copolymer. [6][7][8][9][10][11][12][13][14][15][16] This behavior is attributed to the large number of controlling parameters, including those for each constituent copolymers and the blending composition, as well as to the possibility of macrophase separation which is not encountered in the neat system.…”

Section: Introductionmentioning

confidence: 99%

“…In the first series, the constituent diblock copolymers of the blend both have nearly symmetric compositions but rather different molecular weights. 7,[9][10][11] In the second series, the constituent diblock copolymers have almost the same molecular weights but complementary compositions. 12 In the third series, the constituent diblock copolymers were composed of a long asymmetric copolymer having a spherical (or cylindrical) morphology and a short symmetric copolymer.…”

Section: Introductionmentioning

confidence: 99%

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Phase Behavior of Binary Blends of Diblock Copolymers

Jin

et al. 2010

J. Phys. Chem. B

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The phase behavior of binary blends of a long symmetric AB diblock copolymer and a short asymmetric AB diblock copolymer is studied using the self-consistent mean-field theory. The investigation focuses on blends with different short diblocks by constructing phase diagrams over the whole blending compositions and a large segregation regime. The influences of the chain length ratio (R) of the long and short diblock copolymers on their miscibility and on the stability of various ordered structures are explored. The theoretical results reveal that the blends have a much more complex phase behavior than each constituent copolymer. With the increase of the volume fraction of the short diblocks in the blends, multiple transitions from a long-period lamellar phase to phases with nonzero interfacial curvatures including cylindrical and spherical phases, and finally to a short-period lamellar phase or disordered phase, are predicted. In particular, consistent with experiments, the theory predicts that the cylindrical phase is stabilized over a wide blending compositions region in the strong segregation region, even though the two constituent diblock copolymers are both lamella-forming. When the ratio R is large enough, macrophase separation occurs over a wide range of blending compositions in a relatively strong segregation regime. Various coexisting phases, including those of lamellar and disorder, lamellar and cylindrical, cylindrical and cylindrical, cylindrical and disorder, spherical and disorder, and cylindrical and spherical, are predicted. In addition, the density profiles of the typical ordered structures are presented in order to understand the self-organization of the different copolymer chains.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phase Behavior of Binary Blends of Diblock Copolymers

Jin

et al. 2010

J. Phys. Chem. B

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“…A survey of the possible ordered structures for the binary blends of BCPs is schematically illustrated in Figure 9 (based on Hashimoto et al). [42] Similarly, the possibility that both I and II are in the ordered phase, forming either (4) two macroscopically phase-separated structures as illustrated in Figure 9(b) or (5) a single-phase structure as given in Figure 9(c) is also almost out of the question due to the data given in Figure 7 and 8. The only remaining possibility (3), i.e.…”

Section: Resultsmentioning

confidence: 99%

“…The following five possible states of the I/II blend could be considered: [42] Both BCPs I and II are in the disordered phase, forming either (1) a single phase or (2) two phases, (3) I and II are phase-separated with II in the ordered phase and I in the disordered phase, or both I and II are in the ordered phase, forming either (4) two macroscopically phase-separated structures or (5) a single-phase structure. We expected a gradual transition from (3) to (5) from the properties of individual components I and II.…”

Section: Resultsmentioning

confidence: 99%

Self‐Assembled Structures in Block Copolymer Blends: SAXS, SANS and TEM Study

Holoubek

Baldrián

Lal

2007

Macro Chemistry & Physics

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Phenomena associated with the order‐disorder transition, microdomain morphology and phase behavior of a deuterated block copolymer (BCP) blend I/II (where I is dPS‐block‐dPMMA and II is dPS‐block‐PI) were studied by SAXS, SANS and TEM. The studied, almost symmetric, copolymers differ essentially in microdomain morphology. One of them (I) is in disordered microdomain state, while the other (II) displays lamellar morphology at ordinary temperatures. Self‐assembled structures in blends were investigated as a function of concentration of the added microphase‐separated copolymer and temperature. The ODT positions were located in all the blends, the position of ODT depending only slightly on the concentration of the ordered copolymer. A systematic increase in long period D of the lamellar phase is observed with the growing content of the disordered copolymer. The evaluation of TEM shows the gradual diminishing of macrophase separated regions of disordered copolymer I with growing content of the lamellar copolymer II.magnified image

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“…[46] A series of microphase transition studies on binary blends of polystyrene-block-polyisoprene (SI) diblock copolymers have the phase behavior proven to dissent often from the one-component approximation. [47][48][49] Liu et al [50] used the self-consistent field theory to determine in a phase diagram the relative stability of different Frank-Kasper phases for binary blends of AB diblock copolymers. This study revealed large regions for the Frank-Kasper phases, especially for the σ phase, and confirmed thereby blending as a novel route to complex structures.…”

Section: Introductionmentioning

confidence: 99%

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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A Phase Diagram for the Binary Blends of Nearly Symmetric Diblock Copolymers. 1. Parameter Space of Molecular Weight Ratio and Blend Composition

Cited by 71 publications

References 36 publications

Phase Behavior of Binary Blends of Diblock Copolymers

Phase Behavior of Binary Blends of Diblock Copolymers

Self‐Assembled Structures in Block Copolymer Blends: SAXS, SANS and TEM Study

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

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