Short-chain Length Dependence of Equilibrium Dynamics and Nonlinear Rheology in Unentangled Long-chain/Short-chain Polymer Blends

Xiao-Yang Wang; Bo Liu; Li-Jia An; Zhen-Hua Wang; Yu-Yuan Lu

doi:10.1007/s10118-025-3514-4

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Short-chain Length Dependence of Equilibrium Dynamics and Nonlinear Rheology in Unentangled Long-chain/Short-chain Polymer Blends

RESEARCH ARTICLE | Updated：2026-01-30

- Short-chain Length Dependence of Equilibrium Dynamics and Nonlinear Rheology in Unentangled Long-chain/Short-chain Polymer Blends
- Chinese Journal of Polymer Science Vol. 44, Issue 2, Pages: 525-535(2026)
- Affiliations：
  
  a.State Key Laboratory of Polymer Science and Technology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
  b.School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
  c.Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621000, China
  d.Institute of Polymer Science and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
- Author bio：
  
  zhwang@ciac.ac.cn (Z.H.W.)
  yylu@mail.tsinghua.edu.cn (Y.Y.L.)
- Funds：
- DOI：10.1007/s10118-025-3514-4
  CLC：
- Received：07 October 2025，
  
  Accepted：25 November 2025，
  
  Online First：22 January 2026，
  
  Published：05 February 2026
- Accepted：
Scan QR Code
Wang, X. Y.; Liu, B.; An, L. J.; Wang, Z. H.; Lu, Y. Y. Short-chain length dependence of equilibrium dynamics and nonlinear rheology in unentangled long-chain/short-chain polymer blends. Chinese J. Polym. Sci. 2026, 44, 525–535

Xiao-Yang Wang, Bo Liu, Li-Jia An, et al. Short-chain Length Dependence of Equilibrium Dynamics and Nonlinear Rheology in Unentangled Long-chain/Short-chain Polymer Blends[J]. Chinese Journal of Polymer Science, 2026, 44(2): 525-535.
Wang, X. Y.; Liu, B.; An, L. J.; Wang, Z. H.; Lu, Y. Y. Short-chain length dependence of equilibrium dynamics and nonlinear rheology in unentangled long-chain/short-chain polymer blends. Chinese J. Polym. Sci. 2026, 44, 525–535 DOI： 10.1007/s10118-025-3514-4.

Xiao-Yang Wang, Bo Liu, Li-Jia An, et al. Short-chain Length Dependence of Equilibrium Dynamics and Nonlinear Rheology in Unentangled Long-chain/Short-chain Polymer Blends[J]. Chinese Journal of Polymer Science, 2026, 44(2): 525-535. DOI： 10.1007/s10118-025-3514-4.

摘要

Molecular dynamics simulations reveal that the diffusion coefficient

and the relaxation time

exhibit a strong

non-monotonic

-dependence

transitioning from monomeric friction dominance at small

to collective segmental rearrangement at large

Abstract

The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood

especially regarding the influence of short-chain matrix length

on the structure and rhe

ological behavior of dispersed long chains. Using molecular dynamics simulations based on the Kremer-Grest model

we systematically explore the

-dependence of static conformations

equilibrium dynamics

and nonlinear shear responses in unentangled long-chain/short-chain polymer blends. Our results demonstrate a decoupling between the static and dynamic sensitivity to

: while the static chain size

follows Flory theory with slight swelling at small

due to incomplete excluded volume screening

the diffusion coefficient

and the relaxation time

exhibit a strong

non-monotonic

-dependence

transitioning from monomeric friction dominance at small

to collective segmental rearrangement at large

. Additionally

we observe partial decoupling between the viscous and normal stress responses: while the zero-shear viscosity

is strongly

-dependent

the first and second normal stress coefficients

and

collapse onto universal curves when scaled by the dimensionless shear rate

$$ \dot{\gamma } $$

https://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=99533269&type=

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suggesting a common mechanism of orientation and stretching. Under shear

long chains compress in the vorticity direction

−

0.2

which reduces co

llision frequency and contributes to shear thinning

while the scaling of weaker orientation resistance

0.35

reflects hydrodynamic screening by the short-chain matrix. These findings highlight the limitations of single-chain models and emphasize the necessity of considering

-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.

关键词

Keywords

references

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