{
  "abstract": "The mechanism of water transport through the polyamide active layer of reverse-osmosis membranes is again contested: a 2023 claim that transport is governed by pore flow rather than solution-diffusion reopened a debate many considered settled, and a two-phase treatment has since shown the two descriptions are not mutually exclusive once their coefficients are matched. That reconciliation, however, answers a phenomenological question, not a structural one: whether a genuine, pressure-bearing continuous water phase exists is a separate, testable claim about the material. This Perspective argues that settling it requires two conditions prior work has largely treated as one — an instantaneous through-connected topology, and its survival over the transport timescale — and that the second condition has so far been estimated the wrong way: from the total lifetime of a connectivity interval rather than the residual lifetime seen by a water molecule arriving at a random instant, the same statistical root as the inspection paradox. A dynamic accessibility measure, Adyn = θ·SR(τtr), is proposed to close this gap, built on an intensive areal connectivity measure θ and a residual-lifetime survival function SR rather than an assumed exponential decay. A minimal structural surrogate places the connectivity transition at a model water-accessible volume fraction of 0.14–0.17, close to atomistic estimates for real polyamide, and a comparison of accessible simulation timescales with the residence time implied by realistic operating conditions shows why molecular dynamics alone cannot currently resolve the question. A concrete, falsifiable test agenda is proposed.",
  "abstract_shown": true,
  "affiliations": [
    "V. I. Vernadskii Institute of General and Inorganic Chemistry, National Academy of Sciences of Ukraine"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Ye. O. Kolomiiets"
    },
    {
      "name": "Yevhen Kolomiiets",
      "orcid": "0000-0002-8941-663X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/emjnh1a5pheky.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008523/v1",
  "fulltext_url": null,
  "id": "emjnh1a5pheky",
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  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008523/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2312|Membrane Separation Technologies"
    ]
  ],
  "openalex": "W7212023596",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008523/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-08",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/emjnh1a5pheky.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:19Z",
      "native_id": "10.26434/chemrxiv.15008523",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008523/v2"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:2312|Membrane Separation Technologies",
      "subfield": "hydrology-soils"
    }
  ],
  "title": "Connected, but for how long? A residual-lifetime criterion for the hydraulic–diffusive boundary in polyamide reverse-osmosis membranes",
  "title_text": "Connected, but for how long? A residual-lifetime criterion for the hydraulic–diffusive boundary in polyamide reverse-osmosis membranes",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:19Z",
  "url": "https://research.draconitic.com/paper/emjnh1a5pheky",
  "venue": "ChemRxiv",
  "versions": []
}