Chiral Assembly in Amorphous ABC Triblock Copolymers. Formation of a Helical Morphology in Polystyrene-block-polybutadiene-block-poly(methyl methacrylate) Block Copolymers

Krappe, Udo; Stadler, Reimund; Voigt‐Martin, I. G.

doi:10.1021/ma00117a027

Cited by 203 publications

(189 citation statements)

References 2 publications

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“…Block copolymers give rise to a variety of morphologies as they experience self-assembly based on microphase separation (Bates and Fredrickson (1990); Krappe et al (1995) ;Breiner et al (1998); Kaneko et al (2006); Bates and Fredrickson (1999); Abetz and Boschetti-deFierro (2012)). For diblock copolymers specific microstructures can be achieved by controlling the volume fraction f and the product of χN, where χ is the Flory-Huggins interaction parameter and N the degree of polymerization (Leibler (1980); Matsen and Bates (1997); Khandpur et al (1995)).…”

Section: Introductionmentioning

confidence: 99%

Morphology and elasticity of polystyrene-block-polyisoprene diblock copolymers in the melt

Haenelt

Georgopanos

Abetz

et al. 2014

Korea-Aust. Rheol. J.

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The influence of morphology on the viscoelastic properties of melts of microphase-separated polystyrene-block-polyisoprene (PS-b-PI) diblock copolymers was investigated in oscillatory and creep recovery experiments. By means of anionic polymerization, three PS-b-PI diblock copolymers with a narrow molecular weight distribution and different types of morphology (spherical, cylindrical and lamellar microstructure) were prepared. Linear viscoelastic shear oscillations and creep recovery experiments in shear were performed in order to determine the elastic and viscous properties of the diblock copolymers in the melt at small and large time scales. Our analysis reveals that melts of diblock copolymers are characterized by a pronounced elastic behavior leading to a relatively large recoverable deformation in creep recovery experiments. The elasticity of the diblock copolymers is also revealed by the appearance of the creep-ringing effect. Morphological investigations were carried out to establish relations between microstructure and melt elasticity. Since ordering phenomena take place in melts of diblock copolymers until an equilibrium morphology is achieved, the storage modulus G' of diblock copolymer melts increases with time up to a steady-state value.

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Section: Introductionmentioning

confidence: 99%

Morphology and elasticity of polystyrene-block-polyisoprene diblock copolymers in the melt

Haenelt

Georgopanos

Abetz

et al. 2014

Korea-Aust. Rheol. J.

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“…It has proved possible to engineer molecules to contain aliphatic, aromatic, hydrogen bonding and fluorinated segments, all of which can be combined together (in different ways) to produce differing molecular architectures. In one sense the simplest polyphilic mesogens are linear or star-shaped ABC triblock copolymers, which undergo microphase separation to produce interesting mesophase structures [1][2][3][4].However, the range of molecular architectures possible are limited only by the ingenuity of chemists. Recent interesting examples include the use of calamitic bolaamphiphiles with a rigid rod-like aromatic unit, two hydrophilic terminal groups, and a liphophilic or semifluorinated lateral alkyl chain [5][6][7]; and the use of 'Janus molecules' with two groups of differing mesogens tethered to a molecular core via semi-flexible spacers [8].…”

Section: Introductionmentioning

confidence: 99%

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

Ilnytskyi¹,

Lintuvuori²,

Wilson³

2010

Condens. Matter Phys.

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A coarse-grained simulation model for a third generation liquid crystalline dendrimer (LCDr) is presented. It allows, for the first time, for a successful molecular simulation study of a relation between the shape of a polyphilic macromolecular mesogen and the symmetry of a macroscopic phase. The model dendrimer consists of a soft central sphere and 32 grafted chains each terminated by a mesogen group. The mesogenic pair interactions are modelled by the recently proposed soft core spherocylinder model of Lintuvuori and Wilson [J. Chem. Phys, 128, 044906, (2008)]. Coarse-grained (CG) molecular dynamics (MD) simulations are performed on a melt of 100 molecules in the anisotropic-isobaric ensemble. The model LCDr shows conformational bistability, with both rod-like and disc-like conformations stable at lower temperatures. Each conformation can be induced by an external aligning field of appropriate symmetry that acts on the mesogens (uniaxial for rod-like and planar for disc-like), leading to formation of a monodomain smectic A (Sm A ) or a columnar (Col) phase, respectively. Both phases are stable for approximately the same temperature range and both exhibit a sharp transition to an isotropic cubic-like phase upon heating. We observe a very strong coupling between the conformation of the LCDr and the symmetry of a bulk phase, as suggested previously by theory. The study reveals rich potential in terms of the application of this form of CG modelling to the study of molecular self-assembly of liquid crystalline macromolecules.

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“…The block copolymer consists of two or more covalently bonded polymer chains and self-assembles by microphase separation into a regular microstructure [10][11][12]. The 3-component block terpolymer is widely used for controlling morphology with a complicated microphase separated structure [13][14][15][16][17][18][19][20][21][22][23][24]. Figure 1 shows the triblock polymer samples with (a) hexagonal packed cylinders and (b) tetragonal packed cylinders, respectively.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Block Copolymer Structure using Soft X-Ray Scattering

Nakatani

Harada

Takano

et al. 2017

J. Photopol. Sci. Technol.

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In DSA pattern observation of hp 5 nm and below, the pattern observation method for physical and chemical structures is necessary. Scattering measurement of hard X-rays is one method which can quantitatively evaluate the physical structure of materials. However, when many components such as polymer materials are mixed, it can observe the averaged physical structure, and it is difficult to evaluate the structure of the individual chemical components. Thus, we developed a scattering measurement method using soft X-rays near the carbon absorption edge. Since the absorption spectrum varies in the near carbon absorption edge for each polymer molecule, the individual physical structures can be observed from the scattering profile with different photon energy. In this study, both the physical and chemical structures of the triblock terpolymers such as poly [isopreneblock-styrene-block-(2-vinylpyridine)] which consists of polyisoprene, polystyrene, and poly(2-vinylpyridine) were observed. The physical structure of the triblock polymer observed two types of the packed cylinder structures such as the tetragonal and hexagonal packed structures. The film thickness of this triblock polymer was 400 nm. By varying the photon energy of the scattering measurement, the scattering light intensity changed greatly, and the signal from each polymer could be evaluated. The soft X-ray scattering measurement at the near absorption edge can be measured the molecular structure of a composite material such as a blended polymer individually and can be utilized in material development.

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Chiral Assembly in Amorphous ABC Triblock Copolymers. Formation of a Helical Morphology in Polystyrene-block-polybutadiene-block-poly(methyl methacrylate) Block Copolymers

Cited by 203 publications

References 2 publications

Morphology and elasticity of polystyrene-block-polyisoprene diblock copolymers in the melt

Morphology and elasticity of polystyrene-block-polyisoprene diblock copolymers in the melt

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

Evaluation of Block Copolymer Structure using Soft X-Ray Scattering

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