Morphology and Phase Diagram of Complex Block Copolymers:  ABC Star Triblock Copolymers

Tang, Ping; Qiu, Feng; Zhang, Hongdong; Yang, Yuliang

doi:10.1021/jp037911q

Cited by 120 publications

(168 citation statements)

References 27 publications

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“…We found that these linear and star-shaped ABC terpolymers self-assemble into lamellar phases when using these parameters (Figure 3). The calculations agree with those of Yang et al [18,19] In our simulation, we select the relative deformation from À0.15 to + 0.15, and the corresponding free energies (the free energy of extension or shear) are calculated. Table 1 lists the dimensionless tensile moduli, obtained from Equation (17) for the triblock copolymer system, of lamellar structures having different molecular architectures (linear and star).…”

Section: Resultssupporting

confidence: 81%

“…Based on theoretical studies, linear and starlike block copolymers can assemble into similar ordered microstructures when their components and interaction energies between blocks are nearly identical. [18,19] Our focus in this investigation is to study the influence of the block copolymer architecture on the tensile properties of polymeric nanomaterials having lamellar phases.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Architecture on the Tensile Properties of Triblock Copolymers in a Lamellar Phase

2006

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We have used self-consistent field theory to calculate the tensile moduli of triblock copolymers in lamellar microstructures prepared from linear and star architectures. The extensional moduli K(33) are the main contributors to the tensile moduli, and the contribution of K(U)33 (the internal energy contribution to K(33)) is the main component of the value of K(33). We find that the tensile moduli of ABC three-miktoarm star terpolymers are smaller than those of ABC linear triblock copolymers having identical components, presumably for two main reasons. First, for the ABC three-miktoarm star terpolymers, the contributions of K(U)33 are larger than those of the linear triblock copolymers; we attribute this phenomenon to the star terpolymers having smaller lamellar domain sizes at equilibrium relative to those of the linear triblock copolymers. Second, conformational entropies play an important role in affecting the tensile moduli, mainly because of the different degrees of freedom of the various chains. In contrast, the shear moduli contribute negligibly to the tensile moduli.

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Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Effect of Architecture on the Tensile Properties of Triblock Copolymers in a Lamellar Phase

2006

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“…The crucial differences distinguishing LSO and ostensibly similar ISO/SIO triblocks could potentially be attributed to either the polymer architecture (brush vs. linear) or block-block interactions. We note that architecture-induced segmental mixing has been demonstrated in ABC heteroarm star terpolymers, wherein forming low-energy morphologies may force one arm to transit across an incompatible domain (χ > 0) (45,46). However, these architecture effects do not pertain to brush LSO because the blocks are connected end-to-end in the same way as linear ABC triblock terpolymers.…”

Section: Resultsmentioning

confidence: 85%

Manipulating the ABCs of self-assembly via low-χ block polymer design

Chang

Bates

Lee

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Block polymer self-assembly typically translates molecular chain connectivity into mesoscale structure by exploiting incompatible blocks with large interaction parameters (χ ij ). In this article, we demonstrate that the converse approach, encoding low-χ interactions in ABC bottlebrush triblock terpolymers (χ AC ≲ 0), promotes organization into a unique mixed-domain lamellar morphology, which we designate LAM P . Transmission electron microscopy indicates that LAM P exhibits ACBC domain connectivity, in contrast to conventional three-domain lamellae (LAM 3 ) with ABCB periods. Complementary small-angle X-ray scattering experiments reveal a strongly decreasing domain spacing with increasing total molar mass. Self-consistent field theory reinforces these observations and predicts that LAM P is thermodynamically stable below a critical χ AC , above which LAM 3 emerges. Both experiments and theory expose close analogies to ABA′ triblock copolymer phase behavior, collectively suggesting that low-χ interactions between chemically similar or distinct blocks intimately influence self-assembly. These conclusions provide fresh opportunities for block polymer design with potential consequences spanning all self-assembling soft materials.block polymer | self-assembly | polymer nanostructure | domain spacing | LAM P B lock polymers are a diverse class of soft materials capable of self-assembling into complex periodic nanostructures. Synthetic command over composition, dispersity, sequence, and molecular architecture enables control over the mesoscopic order and macroscopic thermal, mechanical, rheological, and transport properties (1-4). The phase behavior of "simple" linear AB diblock copolymers is universally parameterized by the segregation strength χ AB N and relative volume fraction f, where χ AB represents the effective Flory-Huggins binary interaction parameter and N is the total volume-averaged degree of polymerization. Mixing behavior, captured through the mean-field concept of χ AB , is central to block polymer self-assembly: the competing demands of minimizing interfacial energy and maximizing configurational entropy only favor microphase separation when A-B interactions are repulsive (χ AB > 0) (5, 6). Extension to higher-order multiblock polymers introduces additional interaction parameters (χ ij ) that impact self-assembly and properties (7). For example, introducing a mutually incompatible C block (χ AC > 0, χ BC > 0) generates a host of new morphologies dictated by the chain connectivity (ABC, ACB, or BAC) and intrinsic χ ij -values (8, 9). In this rich phase space, designing multiblock polymers with a combination of miscible and immiscible blocks can also access new structures and impart useful functions (10, 11). Perhaps the best-known examples of such systems are linear ABA′ triblock copolymers (χ AB > 0, χ AA′ ≈ 0): their high-value industrial applications as thermoplastic elastomers are entirely enabled by A/A′ mixing and chain connectivity, which together create physically cross-linked materials with ex...

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“…This theoretical work has been further completed by Tang et al [105,106], Tyler et al [107,108], and more recently by Chen and Xia [109] by using selfconsistent field theory simulations. Playing with the flexibility/rigidity of the polymer segments, various new morphologies could be discovered and some of them have been confirmed experimentally [110][111][112].…”

Section: Bulk Morphologiesmentioning

confidence: 98%

Dynamic Assembly of Block-Copolymers

Quémener¹,

Deratani²,

Lecommandoux³

2011

Constitutional Dynamic Chemistry

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Block copolymers (BCs) are well-known building blocks for the creation of a large variety of nanostructured materials or objects through a dynamic assembly stage which can be either autonomous or guided by an external force. Today's nanotechnologies require sharp control of the overall architecture from the nanoscale to the macroscale. BCs enable this dynamic assembly through all the scales, from few aggregated polymer chains to large bulk polymer materials. Since the discovery of controlled methods to polymerize monomers with different functionalities, a broad diversity of BCs exists, giving rise to many different nanoobjects and nanostructured materials. This chapter will explore the potentialities of block copolymer chains to be assembled through dynamic interactions either in solution or in bulk.

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Morphology and Phase Diagram of Complex Block Copolymers: ABC Star Triblock Copolymers

Cited by 120 publications

References 27 publications

Effect of Architecture on the Tensile Properties of Triblock Copolymers in a Lamellar Phase

Effect of Architecture on the Tensile Properties of Triblock Copolymers in a Lamellar Phase

Manipulating the ABCs of self-assembly via low-χ block polymer design

Dynamic Assembly of Block-Copolymers

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