Coarse-Grained Brownian Dynamics Simulations for Symmetric Diblock Copolymer Melts Based on the Soft Dumbbell Model

Uneyama, Takashi

doi:10.1678/rheology.37.81

Cited by 7 publications

(1 citation statement)

References 33 publications

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“…Similar deceleration effect is also reported for diblock copolymer melts which form lamellar microphase-separated structures. (Uneyama 2009) It should be noted here that the deceleration comes from the property of the correlation function ) (…”

Section: Dynamicsmentioning

confidence: 99%

Linear viscoelasticity of unentangled corona blocks and star arms

Chen

Uneyama

2014

Rheol Acta

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ABA type triblock copolymers form micellar structures consisting of B-rich cores and A-rich coronas in A-selective solvents. The relaxation of A corona is known to be qualitatively similar to, but quantitatively different from that of a star-shaped A chain due to the geometric (spatial) constraint by the core and the thermodynamic (osmotic) constraint. The effect of the geometric constraint on the block dynamics can be modeled by a chain with one end grafted onto an impenetrable wall. We show that the impenetrable wall slightly accelerates the end-to-end vector relaxation in a direction normal to the wall, while it slightly decelerates the viscoelastic terminal relaxation. To test this prediction, we performed linear viscoelastic measurements for model systems: For polystyrene-polyisoprene-polystyrene (SIS) triblock copolymers in S-selective solvent (diethyl phthalate) forming micelles, the viscoelastic relaxation of unentangled S blocks (corona blocks) was found to be slower compared with star-branched S chains having the same molecular weight. This deceleration is partly attributable to the effect of the geometrical constraint.The analysis shows that the deceleration can also be caused by the deformation and rearrangement of micelles, and cooperative and heterogeneous dynamics of S blocks.

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Section: Dynamicsmentioning

confidence: 99%

Linear viscoelasticity of unentangled corona blocks and star arms

Chen

Uneyama

2014

Rheol Acta

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Rheological Properties of Lamellae‐Forming Diblock Copolymers

Tomiyoshi

Kawakatsu

Aoyagi

et al. 2021

Advcd Theory and Sims

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The present study investigates rheological properties of microphase-separated lamellar structures formed by unentangled and weakly entangled diblock copolymer melts under a finite amplitude oscillatory shear flow and a steady shear flow. To simulate such a system, dissipative particle dynamics (DPD) simulation is employed to reproduce the lamellar structures, where a multi-chain slip-spring model is combined with DPD simulation to mimic entanglement effects. By imposing an oscillatory shear flow, this model enables us to measure storage and loss moduli for three different (parallel, perpendicular, and transverse) lamellar orientations with respect to the flow direction. These orientations display distinctive rheological behaviors, and especially the transverse orientation exhibits a peculiar behavior owing to a finite expansion of the lamellar interfaces, which differs from a previous study. In a steady shear flow, steady shear viscosities of parallel and perpendicular orientations are evaluated. In this case, the orientations of lamellar domains and the local orientation and stretching of bonds near the lamellar interfaces affect the steady shear viscosities. A spatial distribution of entanglements also affects the steady shear viscosities differently from another previous study.

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Coarse grain modeling of polyimide copolymers

Chakrabarty

Çağın

2010

Polymer

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Coarse-Grained Brownian Dynamics Simulations for Symmetric Diblock Copolymer Melts Based on the Soft Dumbbell Model

Cited by 7 publications

References 33 publications

Linear viscoelasticity of unentangled corona blocks and star arms

Linear viscoelasticity of unentangled corona blocks and star arms

Rheological Properties of Lamellae‐Forming Diblock Copolymers

Coarse grain modeling of polyimide copolymers

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