Wood cellulose material is stronger than spider silk
Spider silk has long been considered to be the strongest biobased material, and there have been many (successful) attempts in mimicking this material. However, a group of researchers from various institutions have now developed an even stronger biobased material, which consists of nano-sized cellulose fibres.
The quest for more eco-friendly and energy-efficient technologies calls for the development of lightweight structural materials from renewable resources. Nature has long since developed abilities to control the structural features of its building blocks with well-ordered arrangements at nano- and molecular level. The cell wall layer in wood, for instance, is very strong and stiff, consisting of cellulose nanofibrils (CNFs). However, poor adhesion and un-aligned components have prevented researchers from recreating strong materials in macroscale.
In the new research, scientists used so-called ‘flow assisted assembly’ to organise CNFs into a near perfect alignment within macroscale fibres. Even the weakest fibre they created in this way was stronger than other CNF fibres that have been made before. The macroscale fibres are stronger than metal, alloys and glass fibres, while also being stronger and stiffer than dragline spider silk.
The material could be useful in many load-bearing applications, such as lightweight biobased composites for cars and bikes, as well as high-performance medical implants.