Water-Driven Sol–Gel Transition in Native Cellulose/1-Ethyl-3-methylimidazolium Acetate Solutions

Roshan Akdar Mohamed Yunus (1) , Marcus Koch (2) , Philippe Dieudonné-George (3) , Domenico Truzzolillo (3) , Ralph H Colby (4) , Daniele Parisi (1)

1 University of Groningen [Groningen]
2 INM - Leibniz Institute for New Materials
3 L2C - Laboratoire Charles Coulomb
4 Penn State - Pennsylvania State University

The addition of water to native cellulose/1-ethyl-3methylimidazolium acetate solutions catalyzes the formation of gels, where polymer chain-chain intermolecular associations act as cross-links. However, the relationship between water content (Wc), polymer concentration (Cp), and gel strength is still missing. This study provides the fundamentals to design water-induced gels. First, the sol-gel transition occurs exclusively in entangled solutions, while in unentangled ones, intramolecular associations hamper interchain cross-linking, preventing the gel formation. In entangled systems, the addition of water has a dual impact: at low water concentrations, the gel modulus is water-independent and controlled by entanglements. As water increases, more cross-links per chain than entanglements emerge, causing the modulus of the gel to scale as Gp ∼ C p^2 Wc^3.0±0.2. Immersing the solutions in water yields hydrogels with noncrystalline, aggregate-rich structures. Such water-ionic liquid exchange is examined via Raman, FTIR, and WAXS. Our findings provide avenues for designing biogels with desired rheological properties.

Domaines: Matière Molle [cond-mat.soft]; Polymères

Roshan Akdar Mohamed Yunus, Marcus Koch, Philippe Dieudonné-George, Domenico Truzzolillo, Ralph H Colby, et al.. Water-Driven Sol–Gel Transition in Native Cellulose/1-Ethyl-3-methylimidazolium Acetate Solutions. ACS Macro Letters, 2024, 13, pp.219-226. ⟨10.1021/acsmacrolett.3c00710⟩. ⟨hal-04426657⟩