Scaling laws to predict humidity-induced swelling and stiffness in hydrogels

Yiwei Gao, Nicholas K.K. Chai, Negin Garakani, Sujit S. Datta, H. Jeremy Cho

Research output: Contribution to journalArticlepeer-review


From pasta to biological tissues to contact lenses, gel and gel-like materials inherently soften as they swell with water. In dry, low-relative-humidity environments, these materials stiffen as they de-swell with water. Here, we use semi-dilute polymer theory to develop a simple power-law relationship between hydrogel elastic modulus and swelling. From this relationship, we predict hydrogel stiffness or swelling at arbitrary relative humidities. Our close predictions of properties of hydrogels across three different polymer mesh families at varying crosslinking densities and relative humidities demonstrate the validity and generality of our understanding. This predictive capability enables more rapid material discovery and selection for hydrogel applications in varying humidity environments.

Original languageAmerican English
Pages (from-to)9893-9900
Number of pages8
JournalSoft matter
Issue number43
StatePublished - Nov 21 2021
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • General Chemistry

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