Water Swelling-induced Stiffness Enhancement of Polymer Hydrogels

Yi Yu; Wei Zhou; Tao Chen; Wei Lu

doi:10.1007/s10118-026-3597-6

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Water Swelling-induced Stiffness Enhancement of Polymer Hydrogels

Special Topic: Functional Gels | Updated：2026-05-30

- Water Swelling-induced Stiffness Enhancement of Polymer Hydrogels
- Chinese Journal of Polymer Science Vol. 44, Issue 6, Pages: 1749-1759(2026)
- Affiliations：
  
  a.State Key Laboratory of Advanced Marine Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
  b.School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Author bio：
  
  tao.chen@nimte.ac.cn (T.C.)
  luwei@nimte.ac.cn (W.L.)
- Funds：
- DOI：10.1007/s10118-026-3597-6
  CLC：
- Received：30 December 2025，
  
  Accepted：27 January 2026，
  
  Online First：17 April 2026，
  
  Published：05 June 2026
- Accepted：
Scan QR Code
Yu, Y.; Zhou, W.; Chen, T.; Lu, W. Water swelling-induced stiffness enhancement of polymer hydrogels. Chinese J. Polym. Sci. 2026, 44, 1749–1759

Yi Yu, Wei Zhou, Tao Chen, et al. Water Swelling-induced Stiffness Enhancement of Polymer Hydrogels[J]. Chinese Journal of Polymer Science, 2026, 44(6): 1749-1759.
Yu, Y.; Zhou, W.; Chen, T.; Lu, W. Water swelling-induced stiffness enhancement of polymer hydrogels. Chinese J. Polym. Sci. 2026, 44, 1749–1759 DOI： 10.1007/s10118-026-3597-6.

Yi Yu, Wei Zhou, Tao Chen, et al. Water Swelling-induced Stiffness Enhancement of Polymer Hydrogels[J]. Chinese Journal of Polymer Science, 2026, 44(6): 1749-1759. DOI： 10.1007/s10118-026-3597-6.

摘要

A hydrogel film based on the synergistic interaction of hydrophilic and hydrophobic side chains was successfully developed and achieved reversible stiffness changes spanning four orders of magnitude

via

the formation and dissociation of water-induced phase separation.

Abstract

Polymer hydrogels with variable stiffness demonstrate immense practical application value

particularly when utilizing water as a trigger medium

which significantly expands their prospects in soft robotics

bioelectronics

and artificial muscles. However

existing water-induced stiffening hydrogel rely on ionic liquids and inorganic salts

posing leakage risks during prolonged use. Here

we proposed a strategy for mechanically strengthening hydrogel through water-induced phase separation. By designing a polymer matrix featuring hydrophilic oligomeric ethylene glycol methacrylate (OEGMA) and hydrophobic methyl methacrylate (MMA) moieties

this poly[methyl methacrylate-

-poly(ethylene glycol) methacrylate

]

[P(MMA

-OEGMA

)

]

hydrogel

exhibited reversible stiffness switching across four orders of magnitude (from 1.88×10

–2

MPa to 201.63 MPa) upon water stimulation. This abrupt stiffness enhancement stemmed from strong hydrogen bonding between water molecules and hydrophilic OEGMA segments

facilitating spontaneous aggregation and phase separation of hydrophobic MMA segments. The resulting hydrophobic MMA domains formed dynamic physical crosslinking points

thereby enhancing the hydrogel's stiffness. Furthermore

the hydrogel exhibited a time-dependent

multi-stage stiffness enhancement during water swelling. As proof of concept

it was employed as a shape-memory component to explore its application in the controllable programming of multi-stage complex shapes

offering novel design insights for developing environmentally friendly

high-mechanical-performance smart hydrogel materials.

关键词

Keywords

references

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