Gelation under stress: impact of shear flow on the formation and mechanical properties of methylcellulose hydrogels

Arif Z. Nelson; Yilin Wang; Yushi Wang; Anthony S. Margotta; Robert L. Sammler; Aslin Izmitli; Joshua S. Katz; Jaime Curtis-Fisk; Yongfu Li; Randy H. Ewoldt

doi:10.1039/D1SM01711J

Gelation under stress: impact of shear flow on the formation and mechanical properties of methylcellulose hydrogels†

Arif Z. Nelson,

^a Yilin Wang,

^a Yushi Wang,^a Anthony S. Margotta,^a Robert L. Sammler,^b Aslin Izmitli,^c Joshua S. Katz,

^d Jaime Curtis-Fisk,^b Yongfu Li^e and Randy H. Ewoldt

*^a

Author affiliations

* Corresponding authors

^a Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
E-mail: ewoldt@illinois.edu

^b Formulation, Automation, and Material Science and Engineering, Corporate R&D, Dow Inc., Midland, MI 48674, USA

^c Home and Personal Care TS&D, Dow Inc., Collegeville, PA 19426, USA

^d Pharma Solutions R&D, International Flavors & Fragrances, Wilmington, DE 19803, USA

^e Analytical Science, Corporate R&D, Dow Inc., Midland, MI 48674, USA

Abstract

We demonstrate that small unidirectional applied-stresses during temperature-induced gelation dramatically change the gel temperature and the resulting mechanical properties and structure of aqueous methylcellulose (MC), a material that forms a brittle gel with a fibrillar microstructure at elevated temperatures. Applied stress makes gelation more difficult, evidenced by an increased gelation temperature, and weakens mechanical properties of the hot gel, evidenced by a decreased elastic modulus and decreased apparent failure stress. In extreme cases, formation of a fully percolated polymer network is inhibited and a soft granular yield-stress fluid is formed. We quantify the effects of the applied stress using a filament-based mechanical model to relate the measured properties to the structural features of the fibril network. The dramatic changes in the gel temperature and hot gel properties give more design freedom to processing-dependent rheology, but could be detrimental to coating applications where gravitational stress during gelation is unavoidable.

Soft Matter

Gelation under stress: impact of shear flow on the formation and mechanical properties of methylcellulose hydrogels†

Abstract

Supplementary files

Article information

Download Citation

Permissions

Gelation under stress: impact of shear flow on the formation and mechanical properties of methylcellulose hydrogels

Social activity

Search articles by author

Spotlight

Advertisements