The need for renewable bio-based materials that could replace well-established synthetic composite materials is rapidly growing. For example, bio-based materials are increasingly used in applications where a lightweight design should be combined with sustainability and recyclability. However, it is often very challenging to directly transfer the excellent properties of biological materials to a product in a scalable and cost-efficient manner. In this study, we combined delignified wood layers (veneers) and a starch-based glue into bio-based high-performance composites. First, we investigated the ideal amount of starch-based glue between the layers to prevent delamination in the final composite. Then, we produced laminates in unidirectional, cross-ply, and quasi-isotropic configurations using wet processing. Laminates with tensile properties up to 40 GPa and 200 MPa in tensile stiffness and strength, respectively, were fabricated with a very high fiber volume content of up to 80%. The high fiber volume contents led to mechanical interlocks between neighboring fibers and made the need for an additional matrix unnecessary. The water-based laminate process is cost-efficient and scalable and additionally allows one to make full use of delignified wood’s formability by producing shaped parts for various applications.

Natural materials provide an increasingly important role model for the development and processing of next-generation polymers. The velvet worm Euperipatoides rowelli hunts using a projectile, mechanoresponsive adhesive slime that rapidly and reversibly transitions into stiff glassy polymer fibers following shearing and drying. However, the molecular mechanism underlying this mechanoresponsive behavior is still unclear. Previous work showed the slime to be an emulsion of nanoscale charge-stabilized condensed droplets comprised primarily of large phosphorylated proteins, which under mechanical shear coalesce and self-organize into nano- and microfibrils that can be drawn into macroscopic fibers. Here, we utilize wide-angle X-ray diffraction and vibrational spectroscopy coupled with in situ shear deformation to explore the contribution of protein conformation and mechanical forces to the fiber formation process. Although previously believed to be unstructured, our findings indicate that the main phosphorylated protein component possesses a significant β-crystalline structure in the storage phase and that shear-induced partial unfolding of the protein is a key first step in the rapid self-organization of nanodroplets into fibers. The insights gained here have relevance for sustainable production of advanced polymeric materials.