Dual guar/ionic liquid gels and biohybrid material thereof: rheological investigation

Polysaccharide-based ion gels were prepared by mixing biosourced guar gums with imidazolium ionic liquid (IL) molecules that act as crosslinking agents. The in-depth investigation of the rheological properties of the guar/IL solutions emphasized that the shear viscoelastic properties can be finely tuned by IL chemical structure, concentration and molecular weight of guar chains as well as by temperature changes. Under suited conditions, highly elastic physical ion gels were formed as a result of multiple guar/IL, guar/guar and IL/IL interactions. Such synergistic associations were usefully exploited to elaborate films dually composed of guar chains and entrapped IL molecules. Their thermomechanical properties, which revealed a solid-state behavior, were closely controlled by the structural parameters of the constituents. This straightforward approach, which requires no chemical derivatization step, provides a facile way to design physical gels with a large applicative potential.