Substituent Optimization of (1 → 2)-Glucopyranan for Tough, Strong, and Highly Stretchable Film with Dynamic Interchain Interactions.

Polysaccharide is a naturally abundant material, which is regarded as an indispensable scaffold for a structural material. The properties of polysaccharides are dependent not only on the structure of repeating sugar unit but also the glycosidic position between the repeating units. Herein, we report the development of polysaccharide-based self-standing film consisting of naturally occurring (1 → 2)-glucopyranan skeleton. The self-standing film of (1 → 2)-glucopyranan derivative with hexyl carbamate groups is found to be highly stretchable and tough, which exhibits maximum stress of σ = 1.4 MPa, fracture strain of ε ∼ 800%, and the work of extension at fracture ∼ 4 MJ m. It is indicated that the interchain hydrogen bonds in film would serve as energy dissipative bonds for strengthening the film, where the application of mechanical stress to film induces not only the rapture of physical interchain interactions, but also the formation of intrachain hydrogen bonds along the stretching direction. The effects of substituent and glycosidic position of polysaccharide on the properties are discussed in detail.