LAUSR

Significance Circular economy requires materials with a low carbon and environmental footprint. In this context, algae-derived polysaccharides, being a product of carbon dioxide consumption, represent an abundant and sustainable source for engineering materials. Replacing plastics has been challenging as they possess superior properties. Here, a conceptual framework for processing marine polysaccharides into films that possess mechanical properties that are superior to polylactic acid, the most common biodegradable plastic, is presented. At the crux of this system is a network of two polysaccharides possessing vastly different physicochemical characteristics in which simply tuning the calcium concentration leads to films possessing varying degrees of elastic and plastic behavior. The system presented herein represents a significant step toward the exploitation of marine macromolecules in structural composites and consumer products.