Robust <i>β</i>‐Sheet Peptide Reinforced Polymer Fibers

In natural silks, <i>β</i>-sheet crystals are embedded within an amorphous matrix resulting in polypeptide-based nanocomposites. These <i>β</i>-sheet crystals contribute to the subsequent high strength and toughness of spider silk. Consequently, imitation and mimicry of such concepts utilizing polypeptides provide a pathway toward putatively achieving similar properties. Herein, the introduction of poly(l-valine) (PVal) <i>β</i>-sheet nanocrystals into different fibers is investigated. Analysis of micro- and nanoscale features shows that polyvaline <i>β</i>-sheets could be implemented into fibers made from different polymer classes, ranging from standard polymers (polycaprolactone (PCL), Nylon 6) to biopolymers like cellulose and recombinant spider silk. The in situ implementation of PVal during wet-spinning leads to a significant change in the resulting mechanical properties, depending on the polymer used.