{
  "abstract": "We develop a molecularly motivated description of the nonlinear index (NLI) in oscillatory shear deformation of entangled polymers. The central assumption is that the shear component of the tube-orientation tensor cannot grow without bound. Convective constraint release (CCR), chain stretch, and tube dilation progressively reduce the number and lifetime of orientational constraints, but the maximum shear alignment of a tube segment is geometrically limited by $S_{xy}\\leq 1/2$. This motivates a constraint-limited orientation closure in which the NLI first grows approximately with strain amplitude and then approaches the limiting value $\\mathrm{NLI}_{\\max}=3$ asymptotically rather than through an artificial cutoff. The same framework yields a molecular expression for the characteristic half-saturation strain $γ_s$, defined by $\\mathrm{NLI}(γ_s)=3/2$, in terms of the entanglement number, oscillation frequency, and a critical number of remaining orientational constraints. We further derive architecture-dependent expressions for the nonlinear onset strain $γ_c$ for linear, sparsely long-chain-branched, and more regularly branched polymers. The resulting framework provides a compact bridge between Fourier harmonic analysis, CCR-based tube dynamics, and the progressive loss of orientational memory in highly deformed entangled polymer liquids.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Rheologica Acta (2026)",
  "arxiv": "2606.20049",
  "author_total": 2,
  "authors": [
    {
      "name": "Dario Nichetti"
    },
    {
      "name": "Alessio Zaccone"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6kb4zhc7tgfvv.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.20049",
  "fulltext_url": null,
  "id": "6kb4zhc7tgfvv",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.20049",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "arxiv",
      "cond-mat.soft"
    ],
    [
      "arxiv",
      "physics.chem-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.20049",
  "pmcid": null,
  "pmid": null,
  "published": "2026-06-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6kb4zhc7tgfvv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:41Z",
      "native_id": "2606.20049",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.20049"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    },
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Constraint-Limited Tube Orientation of Entangled Polymers in Oscillatory Shear Deformation",
  "title_text": "Constraint-Limited Tube Orientation of Entangled Polymers in Oscillatory Shear Deformation",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:41Z",
  "url": "https://research.draconitic.com/paper/6kb4zhc7tgfvv",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1007/s00397-026-01593-4",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}