# Crossover from entangled to packed state in polymers observed

- Published: 2026-11-06 23:04 UTC
- Section: Machines & Making › Materials science
- Tags: entangled polymers, packed state, strain-induced crossover, mechanical behavior, molecular dynamics simulations
- URL: https://realtech.media/news/rt-3e0190998d0853940169e843_crossover_from_entangled/

**Molecular dynamics simulations reveal strain-induced transition in polymer configurations, impacting mechanical behavior.**

A recent study published in *Nature Communications* explores the mechanical behaviors of entangled polymers through molecular dynamics simulations. The research identifies a strain-induced crossover from an entangled state to a packed state in the inter-chain configuration. This transition occurs after the saturation of primitive chain stretch, leading to convective disentanglement and chain alignment, which reorganizes the system into a packed configuration of aligned segments.

The findings highlight the necessity of considering inter-chain contributions to accurately describe tensile stress beyond the intra-chain conformational stress. This addresses the limitations of traditional tube-based models in strong extensional flows and quantitatively captures the mechanical response at large extensional strains. The study emphasizes how inter-chain reorganization governs the nonlinear extensional behaviors of polymers, providing insights that could enhance applications in polymer processing and life sciences.

This research was conducted by a team from the Department of Engineering Physics at Tsinghua University, Beijing, China, and was supported by the National Natural Science Foundation of China. The authors, Yin Wang, Lin-Feng Wu, Yi-Bo Shao, and Zhe Wang, contributed equally to this work.

## Sources

1. [Nature Communications](https://doi.org/10.1038/s41467-026-78784-3)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-3e0190998d0853940169e843_crossover_from_entangled/