On the role of interface polymers for the mechanics of natural polymeric composites

Research on the deformation mechanisms of tendons and wood has shown that these tissues deform mostly by shearing of a soft matrix between stiff fibres. For this type of composite to be both strong and tough, tight binding between matrix and fibres is required. Recent results suggest that Nature may have evolved special interface polymers, capable both of binding to the fibres and of forming a matrix. Proteoglycans could play this role in tendons by binding to collagen fibrils with their protein-like ends and by forming an aqueous matrix with their sugar-like ends. Hemicelluloses could play a similar role in the plant cell wall, as they are binding to cellulose fibrils and forming aqueous networks between them. This observation suggests that new biomimetic composites might be developed on the basis of amphiphilic polymers capable of binding to stiff fibres and of forming a gel-like matrix around them.