Phys.org June 19, 2024
By swelling with solvent, glassy polymers can become gels that are soft and weak yet have enhanced extensibility. The marked changes in properties arise from the solvent increasing free volume between chains while weakening polymer–polymer interactions. A team of researchers in the US (North Carolina State University, University of Nebraska) developed a unique class of materials called glassy gels with desirable properties of both glasses and gels by solvating polar polymers with ionic liquids at appropriate concentrations. The ionic liquid increases free volume and extensibility despite the absence of conventional solvent. It forms strong and abundant non-covalent crosslinks between polymer chains to render a stiff, tough, glassy, and homogeneous network at room temperature. Despite being more than 54 wt% liquid, the glassy gels exhibited enormous fracture strength, toughness, yield strength, and Young’s modulus, and they could be deformed up to 670% strain with full and rapid recovery on heating. They have adhesive, self-healing and shape-memory properties… read more. TECHNICAL ARTICLE
Toughening mechanism of PAA-PP gels. Credit: Nature, 19 June 2024