# Three-Dimensional Analysis of Macrovoids Formed by Nonsolvent-Induced Phase Separation (NIPS) Using X-ray Microcomputed Tomography (Micro-CT)

https://mdr.nims.go.jp/datasets/fbaf62a8-b42e-49dd-a42c-082fdf6c0834

## File

- [Manuscript_ACSAppliedPolymerMaterials_final.pdf](https://mdr.nims.go.jp/filesets/b29d83fa-8206-47d2-b9a7-d576e0fa002a/download) ([Detail](https://mdr.nims.go.jp/filesets/b29d83fa-8206-47d2-b9a7-d576e0fa002a.md))

## Id

fbaf62a8-b42e-49dd-a42c-082fdf6c0834

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2026-07-29T07:10:52.558665Z

## Updated at

2026-07-29T23:24:15.761005Z

## Published at

2026-07-30T01:31:02.674683Z

## Doi

https://doi.org/10.48505/nims.6430

## First published url

https://doi.org/10.1021/acsapm.6c00505

## Date published

2026-05-22

## Recorded date published

2026-5-22

## Resource type

journal_article

## Manuscript type

accepted_manuscript

## Collection



## Title

- title: Three-Dimensional Analysis of Macrovoids Formed by Nonsolvent-Induced Phase
    Separation (NIPS) Using X-ray Microcomputed Tomography (Micro-CT)
  title_type: original
  lang: en

## Description

- description: "Macrovoids formed in asymmetric membranes by non-solvent-induced phase
    separation (NIPS) critically influence membrane performance; however, it has remained
    experimentally unclear whether their formation is governed by a single dominant
    mechanism or by multiple competing mechanisms. Here, we employ high- resolution
    X-ray microcomputed tomography (micro-CT) to directly visualize and quantitatively
    analyze macrovoids in three dimensions over a sufficiently large field of view.\r\nThree-dimensional
    micro-CT observations reveal the coexistence of two distinct types of macrovoids
    with fundamentally different initiation locations and geometries: surface macrovoids
    that initiate at or near the membrane surface with sharp initiation tips, and
    internal (sub-skin) macrovoids that nucleate beneath the skin layer with rounded
    initiation geometries. Quantitative analysis of depth-dependent structural parameters
    demonstrates that the number density, size distribution, and spatial arrangement
    of these macrovoid types strongly depend on fabrication conditions, such as polymer
    concentration and dope-solution composition, and that competitive growth between
    surface and internal macrovoids governs their final morphologies.\r\nThese three-dimensional
    structural characteristics cannot be resolved by conventional two-dimensional
    characterization techniques. The present results provide direct experimental evidence
    that multiple, process-condition-dependent physical mechanisms govern macrovoid
    formation during NIPS, and establish X-ray micro-CT as a powerful experimental
    approach for elucidating phase-separation phenomena and guiding the rational design
    of asymmetric membranes."
  description_type: abstract
  lang: und

## Creator

- name: Sadaki Samitsu
  role: author
  orcid: https://orcid.org/0000-0002-4139-1656
- name: Misa Hazutani
  role: author
  orcid: https://orcid.org/0009-0005-2901-0506
- name: Miwa Ohniwa
  role: author
  orcid: https://orcid.org/0009-0001-0242-4814

## Contact agent



## Publisher

organization: American Chemical Society (ACS)

## Managing organization



## Keyword

- subject: nonsolvent-induced phase separation (NIPS)
  schema: not_defined
- subject: macrovoid
  schema: not_defined
- subject: X-ray microcomputed tomography (micro-CT)
  schema: not_defined
- subject: three-dimensional structural characterization
  schema: not_defined
- subject: membrane formation mechanism
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by/4.0/

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## Embargo



## Journal

- title: ACS Applied Polymer Materials
  issn: '26376105'
  volume: '8'
  issue: '10'
  start_page: 7307
  end_page: 7315

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## Funding

- identifier: JPMXP1122714694
  funder_name: Ministry of Education, Culture, Sports, Science and Technology
- identifier: JPMJCR23L2
  funder_name: Core Research for Evolutional Science and Technology

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## Fileset

- id: b29d83fa-8206-47d2-b9a7-d576e0fa002a
  filename: Manuscript_ACSAppliedPolymerMaterials_final.pdf
  content_type: application/pdf
  size: 1430393
  md5: 243dddbf71c8a2e828d554d05d682e2d

## Thumbnail

fileset_id: b29d83fa-8206-47d2-b9a7-d576e0fa002a
filename: Manuscript_ACSAppliedPolymerMaterials_final.pdf