Evolution of Microstructure during Shear Alignment in a Polystyrene-Polyisoprene Lamellar Diblock Copolymer

Gupta, Vinay K.; Krishnamoorti, Ramanan; Kornfield, Julia A.; Smith, Steven D.

doi:10.1021/ma00117a015

Cited by 129 publications

(272 citation statements)

References 7 publications

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“…[20][21][22][23][24][25] Takahashi et al studied viscosity 26) , flow-induced structure and related viscoelastic properties 27,28) of poly(styrene-b-2-vinylpyridine)s (SPs) in common good solvents. Since polystyrene (PS) and poly(2-vinylpyridine) (P2VP) have the same Kuhn segment length [29][30][31] , the same glass transition temperature and almost the same viscoelastic properties at melt states and in common good solvents, 32,33) comparison between the data for diblocks and component homopolymers , respectively.…”

Section: Introductionmentioning

confidence: 99%

A Separation Method of Responses from Large Scale Motions and Chain Relaxations for Viscoelastic Properties of Symmetric Poly(styrene-<i>b</i>-2-vinylpyridine)s in the Ordered State

Fang

Takahashi

Takano

et al. 2013

J. Soc. Rheol., Jpn

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Separation method of responses from large scale motions and polymer chain motions are investigated for viscoelastic properties of symmetric poly(styrene-b-2-vinylpyridine)s (SP) in the ordered state taking into account of the effects of flow history on the sample. Due to the almost same thermo-rheological properties of components, master curves of dynamic moduli for SP, G* SP are obtained and shown that the data well coincide with those of polystyrene homopolymers (hPS) at high frequency ω, while responses from large scale motions of lamellar structure, ∆G* grain are observed at low ω, which asymptote to ∆G* grain ~ ω 0.5 . After the pre-shear, magnitude of ∆G* grain became lower at the lower ω region. When the magnitude of G* SP are appropriately higher than ∆G* grain extended to higher ω, ∆G* grain and the responses of polymer chains, ∆G* chain , having Rouse like modes, are successfully obtained by subtraction, ∆G* chain = G* SP -∆G* grain , irrespective of pre-shear. By combining thus obtained ∆G* grain, ∆G* chain , and the data for hPS, G* hPS at higher ω region, G* SP data can be well approximated in a whole frequency range of the measurement.

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Section: Introductionmentioning

confidence: 99%

A Separation Method of Responses from Large Scale Motions and Chain Relaxations for Viscoelastic Properties of Symmetric Poly(styrene-<i>b</i>-2-vinylpyridine)s in the Ordered State

Fang

Takahashi

Takano

et al. 2013

J. Soc. Rheol., Jpn

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“…The outside bounding curves are the neutral stability boundaries so that only within this range a nonlinear solution for ψ exists, with an amplitude A(t) given by Eq. (9). The bending of the curves toward smaller values of q as γ increases can be qualitatively understood by noting that the oscillatory shear leads to a decrease in the lamellar wavelength.…”

Section: Resultsmentioning

confidence: 91%

Lamellar Phase Stability in Diblock Copolymers under Oscillatory Shear Flows

Chen

Viñals

2002

Macromolecules

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A mesoscopic model of a diblock copolymer is used to study the stability of a uniform lamellar phase under a reciprocating shear flow. Approximate viscosity contrast between the microphases is allowed through a linear dependence of the (Newtonian) shear viscosity on monomer composition. We first show that viscosity contrast does not affect the composition of the base lamellar phase in an unbounded geometry, and that it only couples weakly to long wavelength perturbations. A perturbative analysis is then presented to address the stability of uniform lamellar structures under long wavelength perturbations by self-consistently solving for the composition and velocity fields of the perturbations. Stability boundaries are obtained as functions of the physical parameters of the polymer, the parameters of the flow and the initial orientation of the lamellae. We find that all orientations are linearly stable within specific ranges of parameters, but that the perpendicular orientation is generally stable within a larger range than the parallel orientation. Secondary instabilities are both of the Eckhaus type (longitudinal) and zig-zag type (transverse). The former is not expected to lead to re-orientation of the lamella, whereas in the second case the critical wavenumber is typically found to be along the perpendicular orientation.

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“…25 The degree of alignment can be controlled by manipulating variables such as the molecular weight, volume ratio of polymer segments, viscoelastic properties of each polymer component, shear rate (or shear frequency for dynamic shearing), force amplitude, and force direction. 21,22,[26][27][28][29] In one example, Albalak, et al, 25 reported a roll-casting technique to align poly(styrene-block-butadiene-blockstyrene) in the through-plane direction using constant shear. Shear and compression alignment techniques were also successfully applied to the BCE poly(styrenesulfonate-block-methylbutelyne) by Park, et al 12 Although the origin of assembly in mechanical alignment is ascribed to the differences in mechanical properties of each domain, the explicit theory behind the mechanism is still debated.…”

Section: Mechanical Alignmentsmentioning

confidence: 99%

Ion Conduction in Microphase-Separated Block Copolymer Electrolytes

Kambe

Arges

Patel

et al. 2017

Electrochem. Soc. Interface

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Microphase separation of block copolymers provides a promising route towards engineering a mechanically robust ion conducting film for electrochemical devices. The separation into two different nano-domains enables the film to simultaneously exhibit both high ion conductivity and mechanical robustness, material properties inversely related in most homopolymer and random copolymer electrolytes. To exhibit the maximum conductivity and mechanical robustness, both domains would span across macroscopic length scales enabling uninterrupted ion conduction. One way to achieve this architecture is through external alignment fields that are applied during the microphase separation process. In this review, we present the progress and challenges for aligning the ionic domains in block copolymer electrolytes. A survey of alignment and characterization is followed by a discussion of how the nanoscale architecture affects the bulk conductivity and how alignment may be improved to maximize the number of participating conduction domains.

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Evolution of Microstructure during Shear Alignment in a Polystyrene-Polyisoprene Lamellar Diblock Copolymer

Cited by 129 publications

References 7 publications

A Separation Method of Responses from Large Scale Motions and Chain Relaxations for Viscoelastic Properties of Symmetric Poly(styrene-<i>b</i>-2-vinylpyridine)s in the Ordered State

A Separation Method of Responses from Large Scale Motions and Chain Relaxations for Viscoelastic Properties of Symmetric Poly(styrene-<i>b</i>-2-vinylpyridine)s in the Ordered State

Lamellar Phase Stability in Diblock Copolymers under Oscillatory Shear Flows

Ion Conduction in Microphase-Separated Block Copolymer Electrolytes

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