纳米固化低聚物熔体的分子流变学

IF 3 2区工程技术 Q2 MECHANICS

Journal of Rheology Pub Date : 2024-03-21 DOI:10.1122/8.0000751

A. B. Yıldırım, A. Erbaş, L. Biancofiore

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引用次数: 1

摘要

我们利用线性和星形低聚物链 (C25H52) 非缠结熔体的非平衡原子分子动力学模拟来研究纳米级赤铁矿 (α-Fe2O3) 沟道内限制下的稳态粘弹性响应。我们报告了 (i) 负（正）第一（第二）法向应力差和 (ii) 低 Wi 下粘弹性张力的存在。为了揭示粘弹性的分子机理，我们将这些效应与键的排列联系起来，这样表面附近的吸收链就能承载施加在壁上的弹性力，而当链在流动方向上变得更加排列整齐时，弹性力就会减弱。据观察，这种排列与薄膜厚度无关，但会随着剪切速率的增加或表面吸引力的减弱而增强。

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Molecular rheology of nanoconfined oligomer melts

We use nonequilibrium atomistic molecular dynamics simulations of unentangled melts of linear and star oligomer chains (C25H52) to study the steady-state viscoelastic response under confinement within nanoscale hematite (α−Fe2O3) channels. We report (i) the negative (positive) first (second) normal stress difference and (ii) the presence of viscoelastic tension at low Wi. With the aim of uncovering the molecular mechanism of viscoelasticity, we link these effects to bond alignment such that absorbed chains near the surface can carry the elastic force exerted on the walls, which decays as the chains become more aligned in the flow direction. This alignment is observed to be independent of the film thickness but enhanced as the shear rate increases or the surface attraction weakens.

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来源期刊

Journal of Rheology 物理-力学

CiteScore

6.60

自引率

12.10%

发文量

100

审稿时长

1 months

期刊介绍： The Journal of Rheology, formerly the Transactions of The Society of Rheology, is published six times per year by The Society of Rheology, a member society of the American Institute of Physics, through AIP Publishing. It provides in-depth interdisciplinary coverage of theoretical and experimental issues drawn from industry and academia. The Journal of Rheology is published for professionals and students in chemistry, physics, engineering, material science, and mathematics.